Thomas Gleixner | ec8f24b | 2019-05-19 13:07:45 +0100 | [diff] [blame] | 1 | # SPDX-License-Identifier: GPL-2.0-only |
Roman Zippel | face437 | 2006-06-08 22:12:45 -0700 | [diff] [blame] | 2 | config DEFCONFIG_LIST |
| 3 | string |
Paolo 'Blaisorblade' Giarrusso | b2670eac | 2006-10-19 23:28:23 -0700 | [diff] [blame] | 4 | depends on !UML |
Roman Zippel | face437 | 2006-06-08 22:12:45 -0700 | [diff] [blame] | 5 | option defconfig_list |
Rob Landley | 47f38ae | 2018-08-08 13:06:43 +0900 | [diff] [blame] | 6 | default "/lib/modules/$(shell,uname -r)/.config" |
Roman Zippel | face437 | 2006-06-08 22:12:45 -0700 | [diff] [blame] | 7 | default "/etc/kernel-config" |
Rob Landley | 47f38ae | 2018-08-08 13:06:43 +0900 | [diff] [blame] | 8 | default "/boot/config-$(shell,uname -r)" |
Masahiro Yamada | 104daea | 2018-05-28 18:21:40 +0900 | [diff] [blame] | 9 | default ARCH_DEFCONFIG |
| 10 | default "arch/$(ARCH)/defconfig" |
Roman Zippel | face437 | 2006-06-08 22:12:45 -0700 | [diff] [blame] | 11 | |
Masahiro Yamada | a435389 | 2018-05-28 18:22:01 +0900 | [diff] [blame] | 12 | config CC_IS_GCC |
| 13 | def_bool $(success,$(CC) --version | head -n 1 | grep -q gcc) |
| 14 | |
| 15 | config GCC_VERSION |
| 16 | int |
Masahiro Yamada | fa7295a | 2019-03-01 16:10:22 +0900 | [diff] [blame] | 17 | default $(shell,$(srctree)/scripts/gcc-version.sh $(CC)) if CC_IS_GCC |
Masahiro Yamada | a435389 | 2018-05-28 18:22:01 +0900 | [diff] [blame] | 18 | default 0 |
| 19 | |
Masahiro Yamada | 469cb73 | 2018-05-28 18:22:02 +0900 | [diff] [blame] | 20 | config CC_IS_CLANG |
| 21 | def_bool $(success,$(CC) --version | head -n 1 | grep -q clang) |
| 22 | |
| 23 | config CLANG_VERSION |
| 24 | int |
| 25 | default $(shell,$(srctree)/scripts/clang-version.sh $(CC)) |
| 26 | |
Masahiro Yamada | 1a927fd | 2019-07-01 09:58:39 +0900 | [diff] [blame] | 27 | config CC_CAN_LINK |
| 28 | def_bool $(success,$(srctree)/scripts/cc-can-link.sh $(CC)) |
| 29 | |
Masahiro Yamada | e9666d1 | 2018-12-31 00:14:15 +0900 | [diff] [blame] | 30 | config CC_HAS_ASM_GOTO |
| 31 | def_bool $(success,$(srctree)/scripts/gcc-goto.sh $(CC)) |
| 32 | |
Peter Collingbourne | 5cf896fb6 | 2019-07-31 18:18:42 -0700 | [diff] [blame] | 33 | config TOOLS_SUPPORT_RELR |
Will Deacon | 2d12294 | 2019-08-20 10:11:54 +0100 | [diff] [blame] | 34 | def_bool $(success,env "CC=$(CC)" "LD=$(LD)" "NM=$(NM)" "OBJCOPY=$(OBJCOPY)" $(srctree)/scripts/tools-support-relr.sh) |
Peter Collingbourne | 5cf896fb6 | 2019-07-31 18:18:42 -0700 | [diff] [blame] | 35 | |
Rasmus Villemoes | eb11186 | 2019-09-13 00:19:25 +0200 | [diff] [blame] | 36 | config CC_HAS_ASM_INLINE |
| 37 | def_bool $(success,echo 'void foo(void) { asm inline (""); }' | $(CC) -x c - -c -o /dev/null) |
| 38 | |
Masahiro Yamada | b303c6d | 2019-02-21 13:13:38 +0900 | [diff] [blame] | 39 | config CC_HAS_WARN_MAYBE_UNINITIALIZED |
| 40 | def_bool $(cc-option,-Wmaybe-uninitialized) |
| 41 | help |
| 42 | GCC >= 4.7 supports this option. |
| 43 | |
| 44 | config CC_DISABLE_WARN_MAYBE_UNINITIALIZED |
| 45 | bool |
| 46 | depends on CC_HAS_WARN_MAYBE_UNINITIALIZED |
| 47 | default CC_IS_GCC && GCC_VERSION < 40900 # unreliable for GCC < 4.9 |
| 48 | help |
| 49 | GCC's -Wmaybe-uninitialized is not reliable by definition. |
| 50 | Lots of false positive warnings are produced in some cases. |
| 51 | |
| 52 | If this option is enabled, -Wno-maybe-uninitialzed is passed |
| 53 | to the compiler to suppress maybe-uninitialized warnings. |
| 54 | |
Peter Oberparleiter | b99b87f7 | 2009-06-17 16:28:03 -0700 | [diff] [blame] | 55 | config CONSTRUCTORS |
| 56 | bool |
Peter Oberparleiter | b99b87f7 | 2009-06-17 16:28:03 -0700 | [diff] [blame] | 57 | |
Peter Zijlstra | e360adb | 2010-10-14 14:01:34 +0800 | [diff] [blame] | 58 | config IRQ_WORK |
| 59 | bool |
Peter Zijlstra | e360adb | 2010-10-14 14:01:34 +0800 | [diff] [blame] | 60 | |
David Daney | 1dbdc6f | 2012-04-19 14:59:57 -0700 | [diff] [blame] | 61 | config BUILDTIME_EXTABLE_SORT |
| 62 | bool |
| 63 | |
Andy Lutomirski | c65eacb | 2016-09-13 14:29:24 -0700 | [diff] [blame] | 64 | config THREAD_INFO_IN_TASK |
| 65 | bool |
| 66 | help |
| 67 | Select this to move thread_info off the stack into task_struct. To |
| 68 | make this work, an arch will need to remove all thread_info fields |
| 69 | except flags and fix any runtime bugs. |
| 70 | |
Andy Lutomirski | c6c314a | 2016-09-15 22:45:43 -0700 | [diff] [blame] | 71 | One subtle change that will be needed is to use try_get_task_stack() |
| 72 | and put_task_stack() in save_thread_stack_tsk() and get_wchan(). |
| 73 | |
Al Boldi | ff0cfc6 | 2007-07-31 00:39:23 -0700 | [diff] [blame] | 74 | menu "General setup" |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 75 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 76 | config BROKEN |
| 77 | bool |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 78 | |
| 79 | config BROKEN_ON_SMP |
| 80 | bool |
| 81 | depends on BROKEN || !SMP |
| 82 | default y |
| 83 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 84 | config INIT_ENV_ARG_LIMIT |
| 85 | int |
Adrian Bunk | dd673bc | 2006-06-30 01:55:51 -0700 | [diff] [blame] | 86 | default 32 if !UML |
| 87 | default 128 if UML |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 88 | help |
Randy Dunlap | 34ad92c2 | 2005-10-30 15:01:46 -0800 | [diff] [blame] | 89 | Maximum of each of the number of arguments and environment |
| 90 | variables passed to init from the kernel command line. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 91 | |
Jiri Slaby | 4bb1667 | 2013-05-22 10:56:24 +0200 | [diff] [blame] | 92 | config COMPILE_TEST |
| 93 | bool "Compile also drivers which will not load" |
Richard Weinberger | bc083a6 | 2016-08-02 14:03:27 -0700 | [diff] [blame] | 94 | depends on !UML |
Jiri Slaby | 4bb1667 | 2013-05-22 10:56:24 +0200 | [diff] [blame] | 95 | default n |
| 96 | help |
| 97 | Some drivers can be compiled on a different platform than they are |
| 98 | intended to be run on. Despite they cannot be loaded there (or even |
| 99 | when they load they cannot be used due to missing HW support), |
| 100 | developers still, opposing to distributors, might want to build such |
| 101 | drivers to compile-test them. |
| 102 | |
| 103 | If you are a developer and want to build everything available, say Y |
| 104 | here. If you are a user/distributor, say N here to exclude useless |
| 105 | drivers to be distributed. |
| 106 | |
Masahiro Yamada | d6fc9fc | 2019-07-01 09:58:40 +0900 | [diff] [blame] | 107 | config UAPI_HEADER_TEST |
| 108 | bool "Compile test UAPI headers" |
Masahiro Yamada | fcbb846 | 2019-11-07 16:14:40 +0900 | [diff] [blame] | 109 | depends on HEADERS_INSTALL && CC_CAN_LINK |
Masahiro Yamada | d6fc9fc | 2019-07-01 09:58:40 +0900 | [diff] [blame] | 110 | help |
| 111 | Compile test headers exported to user-space to ensure they are |
| 112 | self-contained, i.e. compilable as standalone units. |
| 113 | |
| 114 | If you are a developer or tester and want to ensure the exported |
| 115 | headers are self-contained, say Y here. Otherwise, choose N. |
| 116 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 117 | config LOCALVERSION |
| 118 | string "Local version - append to kernel release" |
| 119 | help |
| 120 | Append an extra string to the end of your kernel version. |
| 121 | This will show up when you type uname, for example. |
| 122 | The string you set here will be appended after the contents of |
| 123 | any files with a filename matching localversion* in your |
| 124 | object and source tree, in that order. Your total string can |
| 125 | be a maximum of 64 characters. |
| 126 | |
Ryan Anderson | aaebf43 | 2005-07-31 04:57:49 -0400 | [diff] [blame] | 127 | config LOCALVERSION_AUTO |
| 128 | bool "Automatically append version information to the version string" |
| 129 | default y |
Alexey Dobriyan | ac3339b | 2016-08-02 14:07:21 -0700 | [diff] [blame] | 130 | depends on !COMPILE_TEST |
Ryan Anderson | aaebf43 | 2005-07-31 04:57:49 -0400 | [diff] [blame] | 131 | help |
| 132 | This will try to automatically determine if the current tree is a |
Robert P. J. Day | 6e5a542 | 2007-05-01 23:08:11 +0200 | [diff] [blame] | 133 | release tree by looking for git tags that belong to the current |
| 134 | top of tree revision. |
Ryan Anderson | aaebf43 | 2005-07-31 04:57:49 -0400 | [diff] [blame] | 135 | |
| 136 | A string of the format -gxxxxxxxx will be added to the localversion |
Robert P. J. Day | 6e5a542 | 2007-05-01 23:08:11 +0200 | [diff] [blame] | 137 | if a git-based tree is found. The string generated by this will be |
Ryan Anderson | aaebf43 | 2005-07-31 04:57:49 -0400 | [diff] [blame] | 138 | appended after any matching localversion* files, and after the value |
Robert P. J. Day | 6e5a542 | 2007-05-01 23:08:11 +0200 | [diff] [blame] | 139 | set in CONFIG_LOCALVERSION. |
Ryan Anderson | aaebf43 | 2005-07-31 04:57:49 -0400 | [diff] [blame] | 140 | |
Robert P. J. Day | 6e5a542 | 2007-05-01 23:08:11 +0200 | [diff] [blame] | 141 | (The actual string used here is the first eight characters produced |
| 142 | by running the command: |
| 143 | |
| 144 | $ git rev-parse --verify HEAD |
| 145 | |
| 146 | which is done within the script "scripts/setlocalversion".) |
Ryan Anderson | aaebf43 | 2005-07-31 04:57:49 -0400 | [diff] [blame] | 147 | |
Laura Abbott | 9afb719 | 2018-07-05 17:49:37 -0700 | [diff] [blame] | 148 | config BUILD_SALT |
Krzysztof Kozlowski | e8cf4e9 | 2019-12-04 16:52:28 -0800 | [diff] [blame] | 149 | string "Build ID Salt" |
| 150 | default "" |
| 151 | help |
| 152 | The build ID is used to link binaries and their debug info. Setting |
| 153 | this option will use the value in the calculation of the build id. |
| 154 | This is mostly useful for distributions which want to ensure the |
| 155 | build is unique between builds. It's safe to leave the default. |
Laura Abbott | 9afb719 | 2018-07-05 17:49:37 -0700 | [diff] [blame] | 156 | |
H. Peter Anvin | 2e9f3bd | 2009-01-04 15:41:25 -0800 | [diff] [blame] | 157 | config HAVE_KERNEL_GZIP |
| 158 | bool |
| 159 | |
| 160 | config HAVE_KERNEL_BZIP2 |
| 161 | bool |
| 162 | |
| 163 | config HAVE_KERNEL_LZMA |
| 164 | bool |
| 165 | |
Lasse Collin | 3ebe124 | 2011-01-12 17:01:23 -0800 | [diff] [blame] | 166 | config HAVE_KERNEL_XZ |
| 167 | bool |
| 168 | |
Albin Tonnerre | 7dd65fe | 2010-01-08 14:42:42 -0800 | [diff] [blame] | 169 | config HAVE_KERNEL_LZO |
| 170 | bool |
| 171 | |
Kyungsik Lee | e76e1fd | 2013-07-08 16:01:46 -0700 | [diff] [blame] | 172 | config HAVE_KERNEL_LZ4 |
| 173 | bool |
| 174 | |
Vasily Gorbik | f16466a | 2018-06-12 21:26:35 +0200 | [diff] [blame] | 175 | config HAVE_KERNEL_UNCOMPRESSED |
| 176 | bool |
| 177 | |
Alain Knaff | 30d65db | 2009-01-04 22:46:17 +0100 | [diff] [blame] | 178 | choice |
H. Peter Anvin | 2e9f3bd | 2009-01-04 15:41:25 -0800 | [diff] [blame] | 179 | prompt "Kernel compression mode" |
| 180 | default KERNEL_GZIP |
Vasily Gorbik | f16466a | 2018-06-12 21:26:35 +0200 | [diff] [blame] | 181 | depends on HAVE_KERNEL_GZIP || HAVE_KERNEL_BZIP2 || HAVE_KERNEL_LZMA || HAVE_KERNEL_XZ || HAVE_KERNEL_LZO || HAVE_KERNEL_LZ4 || HAVE_KERNEL_UNCOMPRESSED |
H. Peter Anvin | 2e9f3bd | 2009-01-04 15:41:25 -0800 | [diff] [blame] | 182 | help |
Alain Knaff | 30d65db | 2009-01-04 22:46:17 +0100 | [diff] [blame] | 183 | The linux kernel is a kind of self-extracting executable. |
| 184 | Several compression algorithms are available, which differ |
| 185 | in efficiency, compression and decompression speed. |
| 186 | Compression speed is only relevant when building a kernel. |
| 187 | Decompression speed is relevant at each boot. |
| 188 | |
| 189 | If you have any problems with bzip2 or lzma compressed |
| 190 | kernels, mail me (Alain Knaff) <alain@knaff.lu>. (An older |
| 191 | version of this functionality (bzip2 only), for 2.4, was |
| 192 | supplied by Christian Ludwig) |
| 193 | |
| 194 | High compression options are mostly useful for users, who |
| 195 | are low on disk space (embedded systems), but for whom ram |
| 196 | size matters less. |
| 197 | |
| 198 | If in doubt, select 'gzip' |
| 199 | |
| 200 | config KERNEL_GZIP |
H. Peter Anvin | 2e9f3bd | 2009-01-04 15:41:25 -0800 | [diff] [blame] | 201 | bool "Gzip" |
| 202 | depends on HAVE_KERNEL_GZIP |
| 203 | help |
Albin Tonnerre | 7dd65fe | 2010-01-08 14:42:42 -0800 | [diff] [blame] | 204 | The old and tried gzip compression. It provides a good balance |
| 205 | between compression ratio and decompression speed. |
Alain Knaff | 30d65db | 2009-01-04 22:46:17 +0100 | [diff] [blame] | 206 | |
| 207 | config KERNEL_BZIP2 |
| 208 | bool "Bzip2" |
H. Peter Anvin | 2e9f3bd | 2009-01-04 15:41:25 -0800 | [diff] [blame] | 209 | depends on HAVE_KERNEL_BZIP2 |
Alain Knaff | 30d65db | 2009-01-04 22:46:17 +0100 | [diff] [blame] | 210 | help |
| 211 | Its compression ratio and speed is intermediate. |
Randy Dunlap | 0a4dd35 | 2012-05-31 16:26:46 -0700 | [diff] [blame] | 212 | Decompression speed is slowest among the choices. The kernel |
H. Peter Anvin | 2e9f3bd | 2009-01-04 15:41:25 -0800 | [diff] [blame] | 213 | size is about 10% smaller with bzip2, in comparison to gzip. |
| 214 | Bzip2 uses a large amount of memory. For modern kernels you |
| 215 | will need at least 8MB RAM or more for booting. |
Alain Knaff | 30d65db | 2009-01-04 22:46:17 +0100 | [diff] [blame] | 216 | |
| 217 | config KERNEL_LZMA |
H. Peter Anvin | 2e9f3bd | 2009-01-04 15:41:25 -0800 | [diff] [blame] | 218 | bool "LZMA" |
| 219 | depends on HAVE_KERNEL_LZMA |
| 220 | help |
Randy Dunlap | 0a4dd35 | 2012-05-31 16:26:46 -0700 | [diff] [blame] | 221 | This compression algorithm's ratio is best. Decompression speed |
| 222 | is between gzip and bzip2. Compression is slowest. |
| 223 | The kernel size is about 33% smaller with LZMA in comparison to gzip. |
Alain Knaff | 30d65db | 2009-01-04 22:46:17 +0100 | [diff] [blame] | 224 | |
Lasse Collin | 3ebe124 | 2011-01-12 17:01:23 -0800 | [diff] [blame] | 225 | config KERNEL_XZ |
| 226 | bool "XZ" |
| 227 | depends on HAVE_KERNEL_XZ |
| 228 | help |
| 229 | XZ uses the LZMA2 algorithm and instruction set specific |
| 230 | BCJ filters which can improve compression ratio of executable |
| 231 | code. The size of the kernel is about 30% smaller with XZ in |
| 232 | comparison to gzip. On architectures for which there is a BCJ |
| 233 | filter (i386, x86_64, ARM, IA-64, PowerPC, and SPARC), XZ |
| 234 | will create a few percent smaller kernel than plain LZMA. |
| 235 | |
| 236 | The speed is about the same as with LZMA: The decompression |
| 237 | speed of XZ is better than that of bzip2 but worse than gzip |
| 238 | and LZO. Compression is slow. |
| 239 | |
Albin Tonnerre | 7dd65fe | 2010-01-08 14:42:42 -0800 | [diff] [blame] | 240 | config KERNEL_LZO |
| 241 | bool "LZO" |
| 242 | depends on HAVE_KERNEL_LZO |
| 243 | help |
Randy Dunlap | 0a4dd35 | 2012-05-31 16:26:46 -0700 | [diff] [blame] | 244 | Its compression ratio is the poorest among the choices. The kernel |
Stephan Sperber | 681b304 | 2010-07-14 11:23:08 +0200 | [diff] [blame] | 245 | size is about 10% bigger than gzip; however its speed |
Albin Tonnerre | 7dd65fe | 2010-01-08 14:42:42 -0800 | [diff] [blame] | 246 | (both compression and decompression) is the fastest. |
| 247 | |
Kyungsik Lee | e76e1fd | 2013-07-08 16:01:46 -0700 | [diff] [blame] | 248 | config KERNEL_LZ4 |
| 249 | bool "LZ4" |
| 250 | depends on HAVE_KERNEL_LZ4 |
| 251 | help |
| 252 | LZ4 is an LZ77-type compressor with a fixed, byte-oriented encoding. |
| 253 | A preliminary version of LZ4 de/compression tool is available at |
| 254 | <https://code.google.com/p/lz4/>. |
| 255 | |
| 256 | Its compression ratio is worse than LZO. The size of the kernel |
| 257 | is about 8% bigger than LZO. But the decompression speed is |
| 258 | faster than LZO. |
| 259 | |
Vasily Gorbik | f16466a | 2018-06-12 21:26:35 +0200 | [diff] [blame] | 260 | config KERNEL_UNCOMPRESSED |
| 261 | bool "None" |
| 262 | depends on HAVE_KERNEL_UNCOMPRESSED |
| 263 | help |
| 264 | Produce uncompressed kernel image. This option is usually not what |
| 265 | you want. It is useful for debugging the kernel in slow simulation |
| 266 | environments, where decompressing and moving the kernel is awfully |
| 267 | slow. This option allows early boot code to skip the decompressor |
| 268 | and jump right at uncompressed kernel image. |
| 269 | |
Alain Knaff | 30d65db | 2009-01-04 22:46:17 +0100 | [diff] [blame] | 270 | endchoice |
| 271 | |
Josh Triplett | bd5dc17 | 2011-06-15 15:08:28 -0700 | [diff] [blame] | 272 | config DEFAULT_HOSTNAME |
| 273 | string "Default hostname" |
| 274 | default "(none)" |
| 275 | help |
| 276 | This option determines the default system hostname before userspace |
| 277 | calls sethostname(2). The kernel traditionally uses "(none)" here, |
| 278 | but you may wish to use a different default here to make a minimal |
| 279 | system more usable with less configuration. |
| 280 | |
Christoph Hellwig | 17c46a6 | 2018-07-31 13:39:29 +0200 | [diff] [blame] | 281 | # |
| 282 | # For some reason microblaze and nios2 hard code SWAP=n. Hopefully we can |
| 283 | # add proper SWAP support to them, in which case this can be remove. |
| 284 | # |
| 285 | config ARCH_NO_SWAP |
| 286 | bool |
| 287 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 288 | config SWAP |
| 289 | bool "Support for paging of anonymous memory (swap)" |
Christoph Hellwig | 17c46a6 | 2018-07-31 13:39:29 +0200 | [diff] [blame] | 290 | depends on MMU && BLOCK && !ARCH_NO_SWAP |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 291 | default y |
| 292 | help |
| 293 | This option allows you to choose whether you want to have support |
Jesper Juhl | 92c3504 | 2006-01-15 02:40:08 +0100 | [diff] [blame] | 294 | for so called swap devices or swap files in your kernel that are |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 295 | used to provide more virtual memory than the actual RAM present |
| 296 | in your computer. If unsure say Y. |
| 297 | |
| 298 | config SYSVIPC |
| 299 | bool "System V IPC" |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 300 | ---help--- |
| 301 | Inter Process Communication is a suite of library functions and |
| 302 | system calls which let processes (running programs) synchronize and |
| 303 | exchange information. It is generally considered to be a good thing, |
| 304 | and some programs won't run unless you say Y here. In particular, if |
| 305 | you want to run the DOS emulator dosemu under Linux (read the |
| 306 | DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>), |
| 307 | you'll need to say Y here. |
| 308 | |
| 309 | You can find documentation about IPC with "info ipc" and also in |
| 310 | section 6.4 of the Linux Programmer's Guide, available from |
| 311 | <http://www.tldp.org/guides.html>. |
| 312 | |
Eric W. Biederman | a5494dc | 2007-02-14 00:34:06 -0800 | [diff] [blame] | 313 | config SYSVIPC_SYSCTL |
| 314 | bool |
| 315 | depends on SYSVIPC |
| 316 | depends on SYSCTL |
| 317 | default y |
| 318 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 319 | config POSIX_MQUEUE |
| 320 | bool "POSIX Message Queues" |
Kees Cook | 19c9239 | 2012-10-02 11:19:29 -0700 | [diff] [blame] | 321 | depends on NET |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 322 | ---help--- |
| 323 | POSIX variant of message queues is a part of IPC. In POSIX message |
| 324 | queues every message has a priority which decides about succession |
| 325 | of receiving it by a process. If you want to compile and run |
| 326 | programs written e.g. for Solaris with use of its POSIX message |
Robert P. J. Day | b0e37650 | 2007-05-09 07:25:13 +0200 | [diff] [blame] | 327 | queues (functions mq_*) say Y here. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 328 | |
| 329 | POSIX message queues are visible as a filesystem called 'mqueue' |
| 330 | and can be mounted somewhere if you want to do filesystem |
| 331 | operations on message queues. |
| 332 | |
| 333 | If unsure, say Y. |
| 334 | |
Serge E. Hallyn | bdc8e5f | 2009-04-06 19:01:11 -0700 | [diff] [blame] | 335 | config POSIX_MQUEUE_SYSCTL |
| 336 | bool |
| 337 | depends on POSIX_MQUEUE |
| 338 | depends on SYSCTL |
| 339 | default y |
| 340 | |
Konstantin Khlebnikov | 226b4cc | 2014-06-04 16:10:50 -0700 | [diff] [blame] | 341 | config CROSS_MEMORY_ATTACH |
| 342 | bool "Enable process_vm_readv/writev syscalls" |
| 343 | depends on MMU |
| 344 | default y |
| 345 | help |
| 346 | Enabling this option adds the system calls process_vm_readv and |
| 347 | process_vm_writev which allow a process with the correct privileges |
Geert Uytterhoeven | a2a368d | 2014-08-12 13:46:11 -0700 | [diff] [blame] | 348 | to directly read from or write to another process' address space. |
Konstantin Khlebnikov | 226b4cc | 2014-06-04 16:10:50 -0700 | [diff] [blame] | 349 | See the man page for more details. |
| 350 | |
Josh Triplett | 69369a7 | 2014-04-03 14:48:27 -0700 | [diff] [blame] | 351 | config USELIB |
| 352 | bool "uselib syscall" |
Riku Voipio | b2113a4 | 2016-01-15 16:58:13 -0800 | [diff] [blame] | 353 | def_bool ALPHA || M68K || SPARC || X86_32 || IA32_EMULATION |
Josh Triplett | 69369a7 | 2014-04-03 14:48:27 -0700 | [diff] [blame] | 354 | help |
| 355 | This option enables the uselib syscall, a system call used in the |
| 356 | dynamic linker from libc5 and earlier. glibc does not use this |
| 357 | system call. If you intend to run programs built on libc5 or |
| 358 | earlier, you may need to enable this syscall. Current systems |
| 359 | running glibc can safely disable this. |
| 360 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 361 | config AUDIT |
| 362 | bool "Auditing support" |
Chris Wright | 804a6a49 | 2005-05-11 10:52:45 +0100 | [diff] [blame] | 363 | depends on NET |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 364 | help |
| 365 | Enable auditing infrastructure that can be used with another |
| 366 | kernel subsystem, such as SELinux (which requires this for |
Paul Moore | cb74ed2 | 2016-01-13 09:18:55 -0500 | [diff] [blame] | 367 | logging of avc messages output). System call auditing is included |
| 368 | on architectures which support it. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 369 | |
AKASHI Takahiro | 7a01772 | 2014-02-25 18:16:24 +0900 | [diff] [blame] | 370 | config HAVE_ARCH_AUDITSYSCALL |
| 371 | bool |
| 372 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 373 | config AUDITSYSCALL |
Paul Moore | cb74ed2 | 2016-01-13 09:18:55 -0500 | [diff] [blame] | 374 | def_bool y |
AKASHI Takahiro | 7a01772 | 2014-02-25 18:16:24 +0900 | [diff] [blame] | 375 | depends on AUDIT && HAVE_ARCH_AUDITSYSCALL |
Eric Paris | 28a3a7e | 2009-12-17 20:12:05 -0500 | [diff] [blame] | 376 | select FSNOTIFY |
Al Viro | 74c3cbe | 2007-07-22 08:04:18 -0400 | [diff] [blame] | 377 | |
Thomas Gleixner | d9817eb | 2010-09-27 12:45:59 +0000 | [diff] [blame] | 378 | source "kernel/irq/Kconfig" |
Thomas Gleixner | 764e0da | 2012-05-21 23:16:18 +0200 | [diff] [blame] | 379 | source "kernel/time/Kconfig" |
Christoph Hellwig | 87a4c37 | 2018-07-31 13:39:32 +0200 | [diff] [blame] | 380 | source "kernel/Kconfig.preempt" |
Thomas Gleixner | d9817eb | 2010-09-27 12:45:59 +0000 | [diff] [blame] | 381 | |
Frederic Weisbecker | 391dc69 | 2012-09-09 14:22:07 +0200 | [diff] [blame] | 382 | menu "CPU/Task time and stats accounting" |
| 383 | |
Frederic Weisbecker | abf917c | 2012-07-25 07:56:04 +0200 | [diff] [blame] | 384 | config VIRT_CPU_ACCOUNTING |
| 385 | bool |
| 386 | |
Frederic Weisbecker | fdf9c35 | 2012-09-09 14:56:31 +0200 | [diff] [blame] | 387 | choice |
| 388 | prompt "Cputime accounting" |
| 389 | default TICK_CPU_ACCOUNTING if !PPC64 |
Stephen Rothwell | 02fc8d3 | 2013-02-08 14:19:38 +1100 | [diff] [blame] | 390 | default VIRT_CPU_ACCOUNTING_NATIVE if PPC64 |
Frederic Weisbecker | fdf9c35 | 2012-09-09 14:56:31 +0200 | [diff] [blame] | 391 | |
| 392 | # Kind of a stub config for the pure tick based cputime accounting |
| 393 | config TICK_CPU_ACCOUNTING |
| 394 | bool "Simple tick based cputime accounting" |
Frederic Weisbecker | c58b0df | 2013-04-26 15:16:31 +0200 | [diff] [blame] | 395 | depends on !S390 && !NO_HZ_FULL |
Frederic Weisbecker | fdf9c35 | 2012-09-09 14:56:31 +0200 | [diff] [blame] | 396 | help |
| 397 | This is the basic tick based cputime accounting that maintains |
| 398 | statistics about user, system and idle time spent on per jiffies |
| 399 | granularity. |
| 400 | |
| 401 | If unsure, say Y. |
| 402 | |
Frederic Weisbecker | abf917c | 2012-07-25 07:56:04 +0200 | [diff] [blame] | 403 | config VIRT_CPU_ACCOUNTING_NATIVE |
Frederic Weisbecker | 391dc69 | 2012-09-09 14:22:07 +0200 | [diff] [blame] | 404 | bool "Deterministic task and CPU time accounting" |
Frederic Weisbecker | c58b0df | 2013-04-26 15:16:31 +0200 | [diff] [blame] | 405 | depends on HAVE_VIRT_CPU_ACCOUNTING && !NO_HZ_FULL |
Frederic Weisbecker | abf917c | 2012-07-25 07:56:04 +0200 | [diff] [blame] | 406 | select VIRT_CPU_ACCOUNTING |
Frederic Weisbecker | 391dc69 | 2012-09-09 14:22:07 +0200 | [diff] [blame] | 407 | help |
| 408 | Select this option to enable more accurate task and CPU time |
| 409 | accounting. This is done by reading a CPU counter on each |
| 410 | kernel entry and exit and on transitions within the kernel |
| 411 | between system, softirq and hardirq state, so there is a |
| 412 | small performance impact. In the case of s390 or IBM POWER > 5, |
| 413 | this also enables accounting of stolen time on logically-partitioned |
| 414 | systems. |
| 415 | |
Frederic Weisbecker | abf917c | 2012-07-25 07:56:04 +0200 | [diff] [blame] | 416 | config VIRT_CPU_ACCOUNTING_GEN |
| 417 | bool "Full dynticks CPU time accounting" |
Kevin Hilman | ff3fb25 | 2013-09-16 15:28:19 -0700 | [diff] [blame] | 418 | depends on HAVE_CONTEXT_TRACKING |
Kevin Hilman | 554b000 | 2013-09-16 15:28:21 -0700 | [diff] [blame] | 419 | depends on HAVE_VIRT_CPU_ACCOUNTING_GEN |
Arnd Bergmann | 041a157 | 2019-03-04 21:01:31 +0100 | [diff] [blame] | 420 | depends on GENERIC_CLOCKEVENTS |
Frederic Weisbecker | abf917c | 2012-07-25 07:56:04 +0200 | [diff] [blame] | 421 | select VIRT_CPU_ACCOUNTING |
| 422 | select CONTEXT_TRACKING |
| 423 | help |
| 424 | Select this option to enable task and CPU time accounting on full |
| 425 | dynticks systems. This accounting is implemented by watching every |
| 426 | kernel-user boundaries using the context tracking subsystem. |
| 427 | The accounting is thus performed at the expense of some significant |
| 428 | overhead. |
| 429 | |
| 430 | For now this is only useful if you are working on the full |
| 431 | dynticks subsystem development. |
| 432 | |
| 433 | If unsure, say N. |
| 434 | |
Rik van Riel | b58c358 | 2016-07-13 16:50:02 +0200 | [diff] [blame] | 435 | endchoice |
| 436 | |
Frederic Weisbecker | fdf9c35 | 2012-09-09 14:56:31 +0200 | [diff] [blame] | 437 | config IRQ_TIME_ACCOUNTING |
| 438 | bool "Fine granularity task level IRQ time accounting" |
Rik van Riel | b58c358 | 2016-07-13 16:50:02 +0200 | [diff] [blame] | 439 | depends on HAVE_IRQ_TIME_ACCOUNTING && !VIRT_CPU_ACCOUNTING_NATIVE |
Frederic Weisbecker | fdf9c35 | 2012-09-09 14:56:31 +0200 | [diff] [blame] | 440 | help |
| 441 | Select this option to enable fine granularity task irq time |
| 442 | accounting. This is done by reading a timestamp on each |
| 443 | transitions between softirq and hardirq state, so there can be a |
| 444 | small performance impact. |
| 445 | |
| 446 | If in doubt, say N here. |
| 447 | |
Vincent Guittot | 11d4afd | 2018-09-25 11:17:42 +0200 | [diff] [blame] | 448 | config HAVE_SCHED_AVG_IRQ |
| 449 | def_bool y |
| 450 | depends on IRQ_TIME_ACCOUNTING || PARAVIRT_TIME_ACCOUNTING |
| 451 | depends on SMP |
| 452 | |
Frederic Weisbecker | 391dc69 | 2012-09-09 14:22:07 +0200 | [diff] [blame] | 453 | config BSD_PROCESS_ACCT |
| 454 | bool "BSD Process Accounting" |
Iulia Manda | 2813893 | 2015-04-15 16:16:41 -0700 | [diff] [blame] | 455 | depends on MULTIUSER |
Frederic Weisbecker | 391dc69 | 2012-09-09 14:22:07 +0200 | [diff] [blame] | 456 | help |
| 457 | If you say Y here, a user level program will be able to instruct the |
| 458 | kernel (via a special system call) to write process accounting |
| 459 | information to a file: whenever a process exits, information about |
| 460 | that process will be appended to the file by the kernel. The |
| 461 | information includes things such as creation time, owning user, |
| 462 | command name, memory usage, controlling terminal etc. (the complete |
| 463 | list is in the struct acct in <file:include/linux/acct.h>). It is |
| 464 | up to the user level program to do useful things with this |
| 465 | information. This is generally a good idea, so say Y. |
| 466 | |
| 467 | config BSD_PROCESS_ACCT_V3 |
| 468 | bool "BSD Process Accounting version 3 file format" |
| 469 | depends on BSD_PROCESS_ACCT |
| 470 | default n |
| 471 | help |
| 472 | If you say Y here, the process accounting information is written |
| 473 | in a new file format that also logs the process IDs of each |
Randy Dunlap | 3903bf9 | 2018-08-21 21:58:34 -0700 | [diff] [blame] | 474 | process and its parent. Note that this file format is incompatible |
Frederic Weisbecker | 391dc69 | 2012-09-09 14:22:07 +0200 | [diff] [blame] | 475 | with previous v0/v1/v2 file formats, so you will need updated tools |
| 476 | for processing it. A preliminary version of these tools is available |
| 477 | at <http://www.gnu.org/software/acct/>. |
| 478 | |
| 479 | config TASKSTATS |
Kees Cook | 19c9239 | 2012-10-02 11:19:29 -0700 | [diff] [blame] | 480 | bool "Export task/process statistics through netlink" |
Frederic Weisbecker | 391dc69 | 2012-09-09 14:22:07 +0200 | [diff] [blame] | 481 | depends on NET |
Iulia Manda | 2813893 | 2015-04-15 16:16:41 -0700 | [diff] [blame] | 482 | depends on MULTIUSER |
Frederic Weisbecker | 391dc69 | 2012-09-09 14:22:07 +0200 | [diff] [blame] | 483 | default n |
| 484 | help |
| 485 | Export selected statistics for tasks/processes through the |
| 486 | generic netlink interface. Unlike BSD process accounting, the |
| 487 | statistics are available during the lifetime of tasks/processes as |
| 488 | responses to commands. Like BSD accounting, they are sent to user |
| 489 | space on task exit. |
| 490 | |
| 491 | Say N if unsure. |
| 492 | |
| 493 | config TASK_DELAY_ACCT |
Kees Cook | 19c9239 | 2012-10-02 11:19:29 -0700 | [diff] [blame] | 494 | bool "Enable per-task delay accounting" |
Frederic Weisbecker | 391dc69 | 2012-09-09 14:22:07 +0200 | [diff] [blame] | 495 | depends on TASKSTATS |
Naveen N. Rao | f6db834 | 2015-06-25 23:53:37 +0530 | [diff] [blame] | 496 | select SCHED_INFO |
Frederic Weisbecker | 391dc69 | 2012-09-09 14:22:07 +0200 | [diff] [blame] | 497 | help |
| 498 | Collect information on time spent by a task waiting for system |
| 499 | resources like cpu, synchronous block I/O completion and swapping |
| 500 | in pages. Such statistics can help in setting a task's priorities |
| 501 | relative to other tasks for cpu, io, rss limits etc. |
| 502 | |
| 503 | Say N if unsure. |
| 504 | |
| 505 | config TASK_XACCT |
Kees Cook | 19c9239 | 2012-10-02 11:19:29 -0700 | [diff] [blame] | 506 | bool "Enable extended accounting over taskstats" |
Frederic Weisbecker | 391dc69 | 2012-09-09 14:22:07 +0200 | [diff] [blame] | 507 | depends on TASKSTATS |
| 508 | help |
| 509 | Collect extended task accounting data and send the data |
| 510 | to userland for processing over the taskstats interface. |
| 511 | |
| 512 | Say N if unsure. |
| 513 | |
| 514 | config TASK_IO_ACCOUNTING |
Kees Cook | 19c9239 | 2012-10-02 11:19:29 -0700 | [diff] [blame] | 515 | bool "Enable per-task storage I/O accounting" |
Frederic Weisbecker | 391dc69 | 2012-09-09 14:22:07 +0200 | [diff] [blame] | 516 | depends on TASK_XACCT |
| 517 | help |
| 518 | Collect information on the number of bytes of storage I/O which this |
| 519 | task has caused. |
| 520 | |
| 521 | Say N if unsure. |
| 522 | |
Johannes Weiner | eb41468 | 2018-10-26 15:06:27 -0700 | [diff] [blame] | 523 | config PSI |
| 524 | bool "Pressure stall information tracking" |
| 525 | help |
| 526 | Collect metrics that indicate how overcommitted the CPU, memory, |
| 527 | and IO capacity are in the system. |
| 528 | |
| 529 | If you say Y here, the kernel will create /proc/pressure/ with the |
| 530 | pressure statistics files cpu, memory, and io. These will indicate |
| 531 | the share of walltime in which some or all tasks in the system are |
| 532 | delayed due to contention of the respective resource. |
| 533 | |
Johannes Weiner | 2ce7135 | 2018-10-26 15:06:31 -0700 | [diff] [blame] | 534 | In kernels with cgroup support, cgroups (cgroup2 only) will |
| 535 | have cpu.pressure, memory.pressure, and io.pressure files, |
| 536 | which aggregate pressure stalls for the grouped tasks only. |
| 537 | |
Mauro Carvalho Chehab | c312355 | 2019-04-17 05:46:08 -0300 | [diff] [blame] | 538 | For more details see Documentation/accounting/psi.rst. |
Johannes Weiner | eb41468 | 2018-10-26 15:06:27 -0700 | [diff] [blame] | 539 | |
| 540 | Say N if unsure. |
| 541 | |
Johannes Weiner | e0c2744 | 2018-11-30 14:09:58 -0800 | [diff] [blame] | 542 | config PSI_DEFAULT_DISABLED |
| 543 | bool "Require boot parameter to enable pressure stall information tracking" |
| 544 | default n |
| 545 | depends on PSI |
| 546 | help |
| 547 | If set, pressure stall information tracking will be disabled |
Baruch Siach | 428a1cb | 2018-12-14 14:17:03 -0800 | [diff] [blame] | 548 | per default but can be enabled through passing psi=1 on the |
| 549 | kernel commandline during boot. |
Johannes Weiner | e0c2744 | 2018-11-30 14:09:58 -0800 | [diff] [blame] | 550 | |
Johannes Weiner | 7b2489d | 2019-02-01 14:21:15 -0800 | [diff] [blame] | 551 | This feature adds some code to the task wakeup and sleep |
| 552 | paths of the scheduler. The overhead is too low to affect |
| 553 | common scheduling-intense workloads in practice (such as |
| 554 | webservers, memcache), but it does show up in artificial |
| 555 | scheduler stress tests, such as hackbench. |
| 556 | |
| 557 | If you are paranoid and not sure what the kernel will be |
| 558 | used for, say Y. |
| 559 | |
| 560 | Say N if unsure. |
| 561 | |
Frederic Weisbecker | 391dc69 | 2012-09-09 14:22:07 +0200 | [diff] [blame] | 562 | endmenu # "CPU/Task time and stats accounting" |
| 563 | |
Frederic Weisbecker | 5c4991e | 2017-10-27 04:42:34 +0200 | [diff] [blame] | 564 | config CPU_ISOLATION |
| 565 | bool "CPU isolation" |
Geert Uytterhoeven | 414a2dc | 2018-01-02 12:13:10 +0100 | [diff] [blame] | 566 | depends on SMP || COMPILE_TEST |
Frederic Weisbecker | 2c43838 | 2017-12-14 19:18:26 +0100 | [diff] [blame] | 567 | default y |
Frederic Weisbecker | 5c4991e | 2017-10-27 04:42:34 +0200 | [diff] [blame] | 568 | help |
| 569 | Make sure that CPUs running critical tasks are not disturbed by |
| 570 | any source of "noise" such as unbound workqueues, timers, kthreads... |
Frederic Weisbecker | 2c43838 | 2017-12-14 19:18:26 +0100 | [diff] [blame] | 571 | Unbound jobs get offloaded to housekeeping CPUs. This is driven by |
| 572 | the "isolcpus=" boot parameter. |
| 573 | |
| 574 | Say Y if unsure. |
Frederic Weisbecker | 5c4991e | 2017-10-27 04:42:34 +0200 | [diff] [blame] | 575 | |
Paul E. McKenney | 0af92d4 | 2017-05-17 08:43:40 -0700 | [diff] [blame] | 576 | source "kernel/rcu/Kconfig" |
Mike Travis | c903ff8 | 2009-01-15 12:28:29 -0800 | [diff] [blame] | 577 | |
Vivek Goyal | de5b56b | 2014-08-08 14:25:41 -0700 | [diff] [blame] | 578 | config BUILD_BIN2C |
| 579 | bool |
| 580 | default n |
| 581 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 582 | config IKCONFIG |
Ross Biro | f2443ab | 2006-09-30 23:27:25 -0700 | [diff] [blame] | 583 | tristate "Kernel .config support" |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 584 | ---help--- |
| 585 | This option enables the complete Linux kernel ".config" file |
| 586 | contents to be saved in the kernel. It provides documentation |
| 587 | of which kernel options are used in a running kernel or in an |
| 588 | on-disk kernel. This information can be extracted from the kernel |
| 589 | image file with the script scripts/extract-ikconfig and used as |
| 590 | input to rebuild the current kernel or to build another kernel. |
| 591 | It can also be extracted from a running kernel by reading |
| 592 | /proc/config.gz if enabled (below). |
| 593 | |
| 594 | config IKCONFIG_PROC |
| 595 | bool "Enable access to .config through /proc/config.gz" |
| 596 | depends on IKCONFIG && PROC_FS |
| 597 | ---help--- |
| 598 | This option enables access to the kernel configuration file |
| 599 | through /proc/config.gz. |
| 600 | |
Joel Fernandes (Google) | f7b101d | 2019-05-15 17:35:51 -0400 | [diff] [blame] | 601 | config IKHEADERS |
| 602 | tristate "Enable kernel headers through /sys/kernel/kheaders.tar.xz" |
| 603 | depends on SYSFS |
Joel Fernandes (Google) | 43d8ce9 | 2019-04-26 15:04:29 -0400 | [diff] [blame] | 604 | help |
Joel Fernandes (Google) | f7b101d | 2019-05-15 17:35:51 -0400 | [diff] [blame] | 605 | This option enables access to the in-kernel headers that are generated during |
| 606 | the build process. These can be used to build eBPF tracing programs, |
| 607 | or similar programs. If you build the headers as a module, a module called |
| 608 | kheaders.ko is built which can be loaded on-demand to get access to headers. |
Joel Fernandes (Google) | 43d8ce9 | 2019-04-26 15:04:29 -0400 | [diff] [blame] | 609 | |
Alistair John Strachan | 794543a | 2007-05-08 00:31:15 -0700 | [diff] [blame] | 610 | config LOG_BUF_SHIFT |
| 611 | int "Kernel log buffer size (16 => 64KB, 17 => 128KB)" |
Ingo Molnar | fb39f98 | 2015-07-01 10:19:11 +0200 | [diff] [blame] | 612 | range 12 25 |
Adrian Bunk | f17a32e | 2008-04-29 00:58:58 -0700 | [diff] [blame] | 613 | default 17 |
Josh Triplett | 361e9df | 2014-10-03 16:00:54 -0700 | [diff] [blame] | 614 | depends on PRINTK |
Alistair John Strachan | 794543a | 2007-05-08 00:31:15 -0700 | [diff] [blame] | 615 | help |
Luis R. Rodriguez | 23b2899 | 2014-08-06 16:08:56 -0700 | [diff] [blame] | 616 | Select the minimal kernel log buffer size as a power of 2. |
| 617 | The final size is affected by LOG_CPU_MAX_BUF_SHIFT config |
| 618 | parameter, see below. Any higher size also might be forced |
| 619 | by "log_buf_len" boot parameter. |
| 620 | |
Adrian Bunk | f17a32e | 2008-04-29 00:58:58 -0700 | [diff] [blame] | 621 | Examples: |
Luis R. Rodriguez | 23b2899 | 2014-08-06 16:08:56 -0700 | [diff] [blame] | 622 | 17 => 128 KB |
Adrian Bunk | f17a32e | 2008-04-29 00:58:58 -0700 | [diff] [blame] | 623 | 16 => 64 KB |
Luis R. Rodriguez | 23b2899 | 2014-08-06 16:08:56 -0700 | [diff] [blame] | 624 | 15 => 32 KB |
| 625 | 14 => 16 KB |
Alistair John Strachan | 794543a | 2007-05-08 00:31:15 -0700 | [diff] [blame] | 626 | 13 => 8 KB |
| 627 | 12 => 4 KB |
| 628 | |
Luis R. Rodriguez | 23b2899 | 2014-08-06 16:08:56 -0700 | [diff] [blame] | 629 | config LOG_CPU_MAX_BUF_SHIFT |
| 630 | int "CPU kernel log buffer size contribution (13 => 8 KB, 17 => 128KB)" |
Geert Uytterhoeven | 2240a31 | 2014-10-13 15:51:11 -0700 | [diff] [blame] | 631 | depends on SMP |
Luis R. Rodriguez | 23b2899 | 2014-08-06 16:08:56 -0700 | [diff] [blame] | 632 | range 0 21 |
| 633 | default 12 if !BASE_SMALL |
| 634 | default 0 if BASE_SMALL |
Josh Triplett | 361e9df | 2014-10-03 16:00:54 -0700 | [diff] [blame] | 635 | depends on PRINTK |
Luis R. Rodriguez | 23b2899 | 2014-08-06 16:08:56 -0700 | [diff] [blame] | 636 | help |
| 637 | This option allows to increase the default ring buffer size |
| 638 | according to the number of CPUs. The value defines the contribution |
| 639 | of each CPU as a power of 2. The used space is typically only few |
| 640 | lines however it might be much more when problems are reported, |
| 641 | e.g. backtraces. |
| 642 | |
| 643 | The increased size means that a new buffer has to be allocated and |
| 644 | the original static one is unused. It makes sense only on systems |
| 645 | with more CPUs. Therefore this value is used only when the sum of |
| 646 | contributions is greater than the half of the default kernel ring |
| 647 | buffer as defined by LOG_BUF_SHIFT. The default values are set |
| 648 | so that more than 64 CPUs are needed to trigger the allocation. |
| 649 | |
| 650 | Also this option is ignored when "log_buf_len" kernel parameter is |
| 651 | used as it forces an exact (power of two) size of the ring buffer. |
| 652 | |
| 653 | The number of possible CPUs is used for this computation ignoring |
Geert Uytterhoeven | 5e0d8d5 | 2016-06-05 10:47:02 +0200 | [diff] [blame] | 654 | hotplugging making the computation optimal for the worst case |
| 655 | scenario while allowing a simple algorithm to be used from bootup. |
Luis R. Rodriguez | 23b2899 | 2014-08-06 16:08:56 -0700 | [diff] [blame] | 656 | |
| 657 | Examples shift values and their meaning: |
| 658 | 17 => 128 KB for each CPU |
| 659 | 16 => 64 KB for each CPU |
| 660 | 15 => 32 KB for each CPU |
| 661 | 14 => 16 KB for each CPU |
| 662 | 13 => 8 KB for each CPU |
| 663 | 12 => 4 KB for each CPU |
| 664 | |
Sergey Senozhatsky | f92bac3 | 2016-12-27 23:16:05 +0900 | [diff] [blame] | 665 | config PRINTK_SAFE_LOG_BUF_SHIFT |
| 666 | int "Temporary per-CPU printk log buffer size (12 => 4KB, 13 => 8KB)" |
Petr Mladek | 427934b | 2016-05-20 17:00:39 -0700 | [diff] [blame] | 667 | range 10 21 |
| 668 | default 13 |
Sergey Senozhatsky | f92bac3 | 2016-12-27 23:16:05 +0900 | [diff] [blame] | 669 | depends on PRINTK |
Petr Mladek | 427934b | 2016-05-20 17:00:39 -0700 | [diff] [blame] | 670 | help |
Sergey Senozhatsky | f92bac3 | 2016-12-27 23:16:05 +0900 | [diff] [blame] | 671 | Select the size of an alternate printk per-CPU buffer where messages |
| 672 | printed from usafe contexts are temporary stored. One example would |
| 673 | be NMI messages, another one - printk recursion. The messages are |
| 674 | copied to the main log buffer in a safe context to avoid a deadlock. |
| 675 | The value defines the size as a power of 2. |
Petr Mladek | 427934b | 2016-05-20 17:00:39 -0700 | [diff] [blame] | 676 | |
Sergey Senozhatsky | f92bac3 | 2016-12-27 23:16:05 +0900 | [diff] [blame] | 677 | Those messages are rare and limited. The largest one is when |
Petr Mladek | 427934b | 2016-05-20 17:00:39 -0700 | [diff] [blame] | 678 | a backtrace is printed. It usually fits into 4KB. Select |
| 679 | 8KB if you want to be on the safe side. |
| 680 | |
| 681 | Examples: |
| 682 | 17 => 128 KB for each CPU |
| 683 | 16 => 64 KB for each CPU |
| 684 | 15 => 32 KB for each CPU |
| 685 | 14 => 16 KB for each CPU |
| 686 | 13 => 8 KB for each CPU |
| 687 | 12 => 4 KB for each CPU |
| 688 | |
KAMEZAWA Hiroyuki | 5cdc38f | 2009-01-07 18:07:30 -0800 | [diff] [blame] | 689 | # |
| 690 | # Architectures with an unreliable sched_clock() should select this: |
| 691 | # |
| 692 | config HAVE_UNSTABLE_SCHED_CLOCK |
| 693 | bool |
| 694 | |
Stephen Boyd | 38ff87f | 2013-06-01 23:39:40 -0700 | [diff] [blame] | 695 | config GENERIC_SCHED_CLOCK |
| 696 | bool |
| 697 | |
Patrick Bellasi | 69842cb | 2019-06-21 09:42:02 +0100 | [diff] [blame] | 698 | menu "Scheduler features" |
| 699 | |
| 700 | config UCLAMP_TASK |
| 701 | bool "Enable utilization clamping for RT/FAIR tasks" |
| 702 | depends on CPU_FREQ_GOV_SCHEDUTIL |
| 703 | help |
| 704 | This feature enables the scheduler to track the clamped utilization |
| 705 | of each CPU based on RUNNABLE tasks scheduled on that CPU. |
| 706 | |
| 707 | With this option, the user can specify the min and max CPU |
| 708 | utilization allowed for RUNNABLE tasks. The max utilization defines |
| 709 | the maximum frequency a task should use while the min utilization |
| 710 | defines the minimum frequency it should use. |
| 711 | |
| 712 | Both min and max utilization clamp values are hints to the scheduler, |
| 713 | aiming at improving its frequency selection policy, but they do not |
| 714 | enforce or grant any specific bandwidth for tasks. |
| 715 | |
| 716 | If in doubt, say N. |
| 717 | |
| 718 | config UCLAMP_BUCKETS_COUNT |
| 719 | int "Number of supported utilization clamp buckets" |
| 720 | range 5 20 |
| 721 | default 5 |
| 722 | depends on UCLAMP_TASK |
| 723 | help |
| 724 | Defines the number of clamp buckets to use. The range of each bucket |
| 725 | will be SCHED_CAPACITY_SCALE/UCLAMP_BUCKETS_COUNT. The higher the |
| 726 | number of clamp buckets the finer their granularity and the higher |
| 727 | the precision of clamping aggregation and tracking at run-time. |
| 728 | |
| 729 | For example, with the minimum configuration value we will have 5 |
| 730 | clamp buckets tracking 20% utilization each. A 25% boosted tasks will |
| 731 | be refcounted in the [20..39]% bucket and will set the bucket clamp |
| 732 | effective value to 25%. |
| 733 | If a second 30% boosted task should be co-scheduled on the same CPU, |
| 734 | that task will be refcounted in the same bucket of the first task and |
| 735 | it will boost the bucket clamp effective value to 30%. |
| 736 | The clamp effective value of a bucket is reset to its nominal value |
| 737 | (20% in the example above) when there are no more tasks refcounted in |
| 738 | that bucket. |
| 739 | |
| 740 | An additional boost/capping margin can be added to some tasks. In the |
| 741 | example above the 25% task will be boosted to 30% until it exits the |
| 742 | CPU. If that should be considered not acceptable on certain systems, |
| 743 | it's always possible to reduce the margin by increasing the number of |
| 744 | clamp buckets to trade off used memory for run-time tracking |
| 745 | precision. |
| 746 | |
| 747 | If in doubt, use the default value. |
| 748 | |
| 749 | endmenu |
| 750 | |
Andrea Arcangeli | be3a728 | 2012-10-04 01:50:47 +0200 | [diff] [blame] | 751 | # |
| 752 | # For architectures that want to enable the support for NUMA-affine scheduler |
| 753 | # balancing logic: |
| 754 | # |
| 755 | config ARCH_SUPPORTS_NUMA_BALANCING |
| 756 | bool |
| 757 | |
Peter Zijlstra | be5e610 | 2013-11-18 18:27:06 +0100 | [diff] [blame] | 758 | # |
Mel Gorman | 72b252a | 2015-09-04 15:47:32 -0700 | [diff] [blame] | 759 | # For architectures that prefer to flush all TLBs after a number of pages |
| 760 | # are unmapped instead of sending one IPI per page to flush. The architecture |
| 761 | # must provide guarantees on what happens if a clean TLB cache entry is |
| 762 | # written after the unmap. Details are in mm/rmap.c near the check for |
| 763 | # should_defer_flush. The architecture should also consider if the full flush |
| 764 | # and the refill costs are offset by the savings of sending fewer IPIs. |
| 765 | config ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH |
| 766 | bool |
| 767 | |
Ard Biesheuvel | c12d336 | 2019-11-08 13:22:27 +0100 | [diff] [blame] | 768 | config CC_HAS_INT128 |
| 769 | def_bool y |
| 770 | depends on !$(cc-option,-D__SIZEOF_INT128__=0) |
| 771 | |
Mel Gorman | 72b252a | 2015-09-04 15:47:32 -0700 | [diff] [blame] | 772 | # |
Peter Zijlstra | be5e610 | 2013-11-18 18:27:06 +0100 | [diff] [blame] | 773 | # For architectures that know their GCC __int128 support is sound |
| 774 | # |
| 775 | config ARCH_SUPPORTS_INT128 |
| 776 | bool |
| 777 | |
Andrea Arcangeli | be3a728 | 2012-10-04 01:50:47 +0200 | [diff] [blame] | 778 | # For architectures that (ab)use NUMA to represent different memory regions |
| 779 | # all cpu-local but of different latencies, such as SuperH. |
| 780 | # |
| 781 | config ARCH_WANT_NUMA_VARIABLE_LOCALITY |
| 782 | bool |
| 783 | |
Andrea Arcangeli | be3a728 | 2012-10-04 01:50:47 +0200 | [diff] [blame] | 784 | config NUMA_BALANCING |
| 785 | bool "Memory placement aware NUMA scheduler" |
Andrea Arcangeli | be3a728 | 2012-10-04 01:50:47 +0200 | [diff] [blame] | 786 | depends on ARCH_SUPPORTS_NUMA_BALANCING |
| 787 | depends on !ARCH_WANT_NUMA_VARIABLE_LOCALITY |
| 788 | depends on SMP && NUMA && MIGRATION |
| 789 | help |
| 790 | This option adds support for automatic NUMA aware memory/task placement. |
| 791 | The mechanism is quite primitive and is based on migrating memory when |
Paul Gortmaker | 6d56a41 | 2013-08-13 11:06:50 -0400 | [diff] [blame] | 792 | it has references to the node the task is running on. |
Andrea Arcangeli | be3a728 | 2012-10-04 01:50:47 +0200 | [diff] [blame] | 793 | |
| 794 | This system will be inactive on UMA systems. |
| 795 | |
Aneesh Kumar K.V | 6f7c97e | 2014-12-10 15:43:37 -0800 | [diff] [blame] | 796 | config NUMA_BALANCING_DEFAULT_ENABLED |
| 797 | bool "Automatically enable NUMA aware memory/task placement" |
| 798 | default y |
| 799 | depends on NUMA_BALANCING |
| 800 | help |
| 801 | If set, automatic NUMA balancing will be enabled if running on a NUMA |
| 802 | machine. |
| 803 | |
Li Zefan | 23964d2 | 2009-01-15 13:50:58 -0800 | [diff] [blame] | 804 | menuconfig CGROUPS |
Christoph Jaeger | 6341e62 | 2014-12-20 15:41:11 -0500 | [diff] [blame] | 805 | bool "Control Group support" |
Tejun Heo | 2bd59d4 | 2014-02-11 11:52:49 -0500 | [diff] [blame] | 806 | select KERNFS |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 807 | help |
Li Zefan | 23964d2 | 2009-01-15 13:50:58 -0800 | [diff] [blame] | 808 | This option adds support for grouping sets of processes together, for |
KAMEZAWA Hiroyuki | 5cdc38f | 2009-01-07 18:07:30 -0800 | [diff] [blame] | 809 | use with process control subsystems such as Cpusets, CFS, memory |
| 810 | controls or device isolation. |
| 811 | See |
Mauro Carvalho Chehab | d6a3b24 | 2019-06-12 14:53:03 -0300 | [diff] [blame] | 812 | - Documentation/scheduler/sched-design-CFS.rst (CFS) |
Mauro Carvalho Chehab | da82c92 | 2019-06-27 13:08:35 -0300 | [diff] [blame] | 813 | - Documentation/admin-guide/cgroup-v1/ (features for grouping, isolation |
Li Zefan | 45ce80f | 2009-01-15 13:50:59 -0800 | [diff] [blame] | 814 | and resource control) |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 815 | |
| 816 | Say N if unsure. |
| 817 | |
Li Zefan | 23964d2 | 2009-01-15 13:50:58 -0800 | [diff] [blame] | 818 | if CGROUPS |
| 819 | |
Johannes Weiner | 3e32cb2 | 2014-12-10 15:42:31 -0800 | [diff] [blame] | 820 | config PAGE_COUNTER |
Krzysztof Kozlowski | e8cf4e9 | 2019-12-04 16:52:28 -0800 | [diff] [blame] | 821 | bool |
Johannes Weiner | 3e32cb2 | 2014-12-10 15:42:31 -0800 | [diff] [blame] | 822 | |
Andrew Morton | c255a45 | 2012-07-31 16:43:02 -0700 | [diff] [blame] | 823 | config MEMCG |
Johannes Weiner | a0166ec | 2015-12-17 17:19:56 -0500 | [diff] [blame] | 824 | bool "Memory controller" |
Johannes Weiner | 3e32cb2 | 2014-12-10 15:42:31 -0800 | [diff] [blame] | 825 | select PAGE_COUNTER |
Tejun Heo | 79bd981 | 2013-11-22 18:20:42 -0500 | [diff] [blame] | 826 | select EVENTFD |
Balbir Singh | 00f0b82 | 2008-03-04 14:28:39 -0800 | [diff] [blame] | 827 | help |
Johannes Weiner | a0166ec | 2015-12-17 17:19:56 -0500 | [diff] [blame] | 828 | Provides control over the memory footprint of tasks in a cgroup. |
Balbir Singh | 00f0b82 | 2008-03-04 14:28:39 -0800 | [diff] [blame] | 829 | |
Andrew Morton | c255a45 | 2012-07-31 16:43:02 -0700 | [diff] [blame] | 830 | config MEMCG_SWAP |
Johannes Weiner | a0166ec | 2015-12-17 17:19:56 -0500 | [diff] [blame] | 831 | bool "Swap controller" |
Andrew Morton | c255a45 | 2012-07-31 16:43:02 -0700 | [diff] [blame] | 832 | depends on MEMCG && SWAP |
KAMEZAWA Hiroyuki | c077719 | 2009-01-07 18:07:57 -0800 | [diff] [blame] | 833 | help |
Johannes Weiner | a0166ec | 2015-12-17 17:19:56 -0500 | [diff] [blame] | 834 | Provides control over the swap space consumed by tasks in a cgroup. |
| 835 | |
Andrew Morton | c255a45 | 2012-07-31 16:43:02 -0700 | [diff] [blame] | 836 | config MEMCG_SWAP_ENABLED |
Johannes Weiner | a0166ec | 2015-12-17 17:19:56 -0500 | [diff] [blame] | 837 | bool "Swap controller enabled by default" |
Andrew Morton | c255a45 | 2012-07-31 16:43:02 -0700 | [diff] [blame] | 838 | depends on MEMCG_SWAP |
Michal Hocko | a42c390 | 2010-11-24 12:57:08 -0800 | [diff] [blame] | 839 | default y |
| 840 | help |
| 841 | Memory Resource Controller Swap Extension comes with its price in |
| 842 | a bigger memory consumption. General purpose distribution kernels |
Jim Cromie | 43d547f | 2010-12-17 14:32:36 -0700 | [diff] [blame] | 843 | which want to enable the feature but keep it disabled by default |
Michal Hocko | 07555ac | 2013-08-22 16:35:46 -0700 | [diff] [blame] | 844 | and let the user enable it by swapaccount=1 boot command line |
Michal Hocko | a42c390 | 2010-11-24 12:57:08 -0800 | [diff] [blame] | 845 | parameter should have this option unselected. |
| 846 | For those who want to have the feature enabled by default should |
| 847 | select this option (if, for some reason, they need to disable it |
WANG Cong | 00a66d2 | 2011-07-25 17:12:12 -0700 | [diff] [blame] | 848 | then swapaccount=0 does the trick). |
KAMEZAWA Hiroyuki | c077719 | 2009-01-07 18:07:57 -0800 | [diff] [blame] | 849 | |
Kirill Tkhai | 84c07d1 | 2018-08-17 15:47:25 -0700 | [diff] [blame] | 850 | config MEMCG_KMEM |
| 851 | bool |
| 852 | depends on MEMCG && !SLOB |
| 853 | default y |
| 854 | |
Johannes Weiner | 6bf024e | 2015-12-17 17:19:57 -0500 | [diff] [blame] | 855 | config BLK_CGROUP |
| 856 | bool "IO controller" |
| 857 | depends on BLOCK |
Aneesh Kumar K.V | 2bc64a2 | 2012-07-31 16:42:12 -0700 | [diff] [blame] | 858 | default n |
Johannes Weiner | 6bf024e | 2015-12-17 17:19:57 -0500 | [diff] [blame] | 859 | ---help--- |
| 860 | Generic block IO controller cgroup interface. This is the common |
| 861 | cgroup interface which should be used by various IO controlling |
| 862 | policies. |
Aneesh Kumar K.V | 2bc64a2 | 2012-07-31 16:42:12 -0700 | [diff] [blame] | 863 | |
Johannes Weiner | 6bf024e | 2015-12-17 17:19:57 -0500 | [diff] [blame] | 864 | Currently, CFQ IO scheduler uses it to recognize task groups and |
| 865 | control disk bandwidth allocation (proportional time slice allocation) |
| 866 | to such task groups. It is also used by bio throttling logic in |
| 867 | block layer to implement upper limit in IO rates on a device. |
Stephane Eranian | e5d1367 | 2011-02-14 11:20:01 +0200 | [diff] [blame] | 868 | |
Johannes Weiner | 6bf024e | 2015-12-17 17:19:57 -0500 | [diff] [blame] | 869 | This option only enables generic Block IO controller infrastructure. |
| 870 | One needs to also enable actual IO controlling logic/policy. For |
| 871 | enabling proportional weight division of disk bandwidth in CFQ, set |
| 872 | CONFIG_CFQ_GROUP_IOSCHED=y; for enabling throttling policy, set |
| 873 | CONFIG_BLK_DEV_THROTTLING=y. |
| 874 | |
Mauro Carvalho Chehab | da82c92 | 2019-06-27 13:08:35 -0300 | [diff] [blame] | 875 | See Documentation/admin-guide/cgroup-v1/blkio-controller.rst for more information. |
Johannes Weiner | 6bf024e | 2015-12-17 17:19:57 -0500 | [diff] [blame] | 876 | |
Johannes Weiner | 6bf024e | 2015-12-17 17:19:57 -0500 | [diff] [blame] | 877 | config CGROUP_WRITEBACK |
| 878 | bool |
| 879 | depends on MEMCG && BLK_CGROUP |
| 880 | default y |
Stephane Eranian | e5d1367 | 2011-02-14 11:20:01 +0200 | [diff] [blame] | 881 | |
Dhaval Giani | 7c94143 | 2010-01-20 13:26:18 +0100 | [diff] [blame] | 882 | menuconfig CGROUP_SCHED |
Johannes Weiner | a0166ec | 2015-12-17 17:19:56 -0500 | [diff] [blame] | 883 | bool "CPU controller" |
Dhaval Giani | 7c94143 | 2010-01-20 13:26:18 +0100 | [diff] [blame] | 884 | default n |
| 885 | help |
| 886 | This feature lets CPU scheduler recognize task groups and control CPU |
| 887 | bandwidth allocation to such task groups. It uses cgroups to group |
| 888 | tasks. |
| 889 | |
| 890 | if CGROUP_SCHED |
| 891 | config FAIR_GROUP_SCHED |
| 892 | bool "Group scheduling for SCHED_OTHER" |
| 893 | depends on CGROUP_SCHED |
| 894 | default CGROUP_SCHED |
| 895 | |
Paul Turner | ab84d31 | 2011-07-21 09:43:28 -0700 | [diff] [blame] | 896 | config CFS_BANDWIDTH |
| 897 | bool "CPU bandwidth provisioning for FAIR_GROUP_SCHED" |
Paul Turner | ab84d31 | 2011-07-21 09:43:28 -0700 | [diff] [blame] | 898 | depends on FAIR_GROUP_SCHED |
| 899 | default n |
| 900 | help |
| 901 | This option allows users to define CPU bandwidth rates (limits) for |
| 902 | tasks running within the fair group scheduler. Groups with no limit |
| 903 | set are considered to be unconstrained and will run with no |
| 904 | restriction. |
Mauro Carvalho Chehab | d6a3b24 | 2019-06-12 14:53:03 -0300 | [diff] [blame] | 905 | See Documentation/scheduler/sched-bwc.rst for more information. |
Paul Turner | ab84d31 | 2011-07-21 09:43:28 -0700 | [diff] [blame] | 906 | |
Dhaval Giani | 7c94143 | 2010-01-20 13:26:18 +0100 | [diff] [blame] | 907 | config RT_GROUP_SCHED |
| 908 | bool "Group scheduling for SCHED_RR/FIFO" |
Dhaval Giani | 7c94143 | 2010-01-20 13:26:18 +0100 | [diff] [blame] | 909 | depends on CGROUP_SCHED |
| 910 | default n |
| 911 | help |
| 912 | This feature lets you explicitly allocate real CPU bandwidth |
Li Zefan | 32bd7eb | 2010-03-24 13:17:19 +0800 | [diff] [blame] | 913 | to task groups. If enabled, it will also make it impossible to |
Dhaval Giani | 7c94143 | 2010-01-20 13:26:18 +0100 | [diff] [blame] | 914 | schedule realtime tasks for non-root users until you allocate |
| 915 | realtime bandwidth for them. |
Mauro Carvalho Chehab | d6a3b24 | 2019-06-12 14:53:03 -0300 | [diff] [blame] | 916 | See Documentation/scheduler/sched-rt-group.rst for more information. |
Dhaval Giani | 7c94143 | 2010-01-20 13:26:18 +0100 | [diff] [blame] | 917 | |
| 918 | endif #CGROUP_SCHED |
| 919 | |
Patrick Bellasi | 2480c09 | 2019-08-22 14:28:06 +0100 | [diff] [blame] | 920 | config UCLAMP_TASK_GROUP |
| 921 | bool "Utilization clamping per group of tasks" |
| 922 | depends on CGROUP_SCHED |
| 923 | depends on UCLAMP_TASK |
| 924 | default n |
| 925 | help |
| 926 | This feature enables the scheduler to track the clamped utilization |
| 927 | of each CPU based on RUNNABLE tasks currently scheduled on that CPU. |
| 928 | |
| 929 | When this option is enabled, the user can specify a min and max |
| 930 | CPU bandwidth which is allowed for each single task in a group. |
| 931 | The max bandwidth allows to clamp the maximum frequency a task |
| 932 | can use, while the min bandwidth allows to define a minimum |
| 933 | frequency a task will always use. |
| 934 | |
| 935 | When task group based utilization clamping is enabled, an eventually |
| 936 | specified task-specific clamp value is constrained by the cgroup |
| 937 | specified clamp value. Both minimum and maximum task clamping cannot |
| 938 | be bigger than the corresponding clamping defined at task group level. |
| 939 | |
| 940 | If in doubt, say N. |
| 941 | |
Johannes Weiner | 6bf024e | 2015-12-17 17:19:57 -0500 | [diff] [blame] | 942 | config CGROUP_PIDS |
| 943 | bool "PIDs controller" |
| 944 | help |
| 945 | Provides enforcement of process number limits in the scope of a |
| 946 | cgroup. Any attempt to fork more processes than is allowed in the |
| 947 | cgroup will fail. PIDs are fundamentally a global resource because it |
| 948 | is fairly trivial to reach PID exhaustion before you reach even a |
| 949 | conservative kmemcg limit. As a result, it is possible to grind a |
| 950 | system to halt without being limited by other cgroup policies. The |
Parav Pandit | 6cc578d | 2016-03-05 11:30:56 +0530 | [diff] [blame] | 951 | PIDs controller is designed to stop this from happening. |
Johannes Weiner | 6bf024e | 2015-12-17 17:19:57 -0500 | [diff] [blame] | 952 | |
| 953 | It should be noted that organisational operations (such as attaching |
Jonathan Neuschäfer | 9807683 | 2019-02-01 14:21:01 -0800 | [diff] [blame] | 954 | to a cgroup hierarchy) will *not* be blocked by the PIDs controller, |
Johannes Weiner | 6bf024e | 2015-12-17 17:19:57 -0500 | [diff] [blame] | 955 | since the PIDs limit only affects a process's ability to fork, not to |
| 956 | attach to a cgroup. |
| 957 | |
Parav Pandit | 39d3e75 | 2017-01-10 00:02:13 +0000 | [diff] [blame] | 958 | config CGROUP_RDMA |
| 959 | bool "RDMA controller" |
| 960 | help |
| 961 | Provides enforcement of RDMA resources defined by IB stack. |
| 962 | It is fairly easy for consumers to exhaust RDMA resources, which |
| 963 | can result into resource unavailability to other consumers. |
| 964 | RDMA controller is designed to stop this from happening. |
| 965 | Attaching processes with active RDMA resources to the cgroup |
| 966 | hierarchy is allowed even if can cross the hierarchy's limit. |
| 967 | |
Johannes Weiner | 6bf024e | 2015-12-17 17:19:57 -0500 | [diff] [blame] | 968 | config CGROUP_FREEZER |
| 969 | bool "Freezer controller" |
| 970 | help |
| 971 | Provides a way to freeze and unfreeze all tasks in a |
| 972 | cgroup. |
| 973 | |
Johannes Weiner | 489c2a2 | 2016-01-20 15:02:41 -0800 | [diff] [blame] | 974 | This option affects the ORIGINAL cgroup interface. The cgroup2 memory |
| 975 | controller includes important in-kernel memory consumers per default. |
| 976 | |
| 977 | If you're using cgroup2, say N. |
| 978 | |
Johannes Weiner | 6bf024e | 2015-12-17 17:19:57 -0500 | [diff] [blame] | 979 | config CGROUP_HUGETLB |
| 980 | bool "HugeTLB controller" |
| 981 | depends on HUGETLB_PAGE |
| 982 | select PAGE_COUNTER |
Vivek Goyal | afc24d4 | 2010-04-26 19:27:56 +0200 | [diff] [blame] | 983 | default n |
Johannes Weiner | 6bf024e | 2015-12-17 17:19:57 -0500 | [diff] [blame] | 984 | help |
| 985 | Provides a cgroup controller for HugeTLB pages. |
| 986 | When you enable this, you can put a per cgroup limit on HugeTLB usage. |
| 987 | The limit is enforced during page fault. Since HugeTLB doesn't |
| 988 | support page reclaim, enforcing the limit at page fault time implies |
| 989 | that, the application will get SIGBUS signal if it tries to access |
| 990 | HugeTLB pages beyond its limit. This requires the application to know |
| 991 | beforehand how much HugeTLB pages it would require for its use. The |
| 992 | control group is tracked in the third page lru pointer. This means |
| 993 | that we cannot use the controller with huge page less than 3 pages. |
Vivek Goyal | afc24d4 | 2010-04-26 19:27:56 +0200 | [diff] [blame] | 994 | |
Johannes Weiner | 6bf024e | 2015-12-17 17:19:57 -0500 | [diff] [blame] | 995 | config CPUSETS |
| 996 | bool "Cpuset controller" |
Nicolas Pitre | e1d4eee | 2017-06-14 13:19:23 -0400 | [diff] [blame] | 997 | depends on SMP |
Johannes Weiner | 6bf024e | 2015-12-17 17:19:57 -0500 | [diff] [blame] | 998 | help |
| 999 | This option will let you create and manage CPUSETs which |
| 1000 | allow dynamically partitioning a system into sets of CPUs and |
| 1001 | Memory Nodes and assigning tasks to run only within those sets. |
| 1002 | This is primarily useful on large SMP or NUMA systems. |
Vivek Goyal | afc24d4 | 2010-04-26 19:27:56 +0200 | [diff] [blame] | 1003 | |
Johannes Weiner | 6bf024e | 2015-12-17 17:19:57 -0500 | [diff] [blame] | 1004 | Say N if unsure. |
Vivek Goyal | afc24d4 | 2010-04-26 19:27:56 +0200 | [diff] [blame] | 1005 | |
Johannes Weiner | 6bf024e | 2015-12-17 17:19:57 -0500 | [diff] [blame] | 1006 | config PROC_PID_CPUSET |
| 1007 | bool "Include legacy /proc/<pid>/cpuset file" |
| 1008 | depends on CPUSETS |
Tejun Heo | 89e9b9e | 2015-05-22 17:13:36 -0400 | [diff] [blame] | 1009 | default y |
| 1010 | |
Johannes Weiner | 6bf024e | 2015-12-17 17:19:57 -0500 | [diff] [blame] | 1011 | config CGROUP_DEVICE |
| 1012 | bool "Device controller" |
| 1013 | help |
| 1014 | Provides a cgroup controller implementing whitelists for |
| 1015 | devices which a process in the cgroup can mknod or open. |
| 1016 | |
| 1017 | config CGROUP_CPUACCT |
| 1018 | bool "Simple CPU accounting controller" |
| 1019 | help |
| 1020 | Provides a simple controller for monitoring the |
| 1021 | total CPU consumed by the tasks in a cgroup. |
| 1022 | |
| 1023 | config CGROUP_PERF |
| 1024 | bool "Perf controller" |
| 1025 | depends on PERF_EVENTS |
| 1026 | help |
| 1027 | This option extends the perf per-cpu mode to restrict monitoring |
| 1028 | to threads which belong to the cgroup specified and run on the |
| 1029 | designated cpu. |
| 1030 | |
| 1031 | Say N if unsure. |
| 1032 | |
Daniel Mack | 3007098 | 2016-11-23 16:52:26 +0100 | [diff] [blame] | 1033 | config CGROUP_BPF |
| 1034 | bool "Support for eBPF programs attached to cgroups" |
Andy Lutomirski | 483c493 | 2016-12-16 08:33:45 -0800 | [diff] [blame] | 1035 | depends on BPF_SYSCALL |
| 1036 | select SOCK_CGROUP_DATA |
Daniel Mack | 3007098 | 2016-11-23 16:52:26 +0100 | [diff] [blame] | 1037 | help |
| 1038 | Allow attaching eBPF programs to a cgroup using the bpf(2) |
| 1039 | syscall command BPF_PROG_ATTACH. |
| 1040 | |
| 1041 | In which context these programs are accessed depends on the type |
| 1042 | of attachment. For instance, programs that are attached using |
| 1043 | BPF_CGROUP_INET_INGRESS will be executed on the ingress path of |
| 1044 | inet sockets. |
| 1045 | |
Johannes Weiner | 6bf024e | 2015-12-17 17:19:57 -0500 | [diff] [blame] | 1046 | config CGROUP_DEBUG |
Waiman Long | 23b0be4 | 2017-06-13 17:18:03 -0400 | [diff] [blame] | 1047 | bool "Debug controller" |
Johannes Weiner | 6bf024e | 2015-12-17 17:19:57 -0500 | [diff] [blame] | 1048 | default n |
Waiman Long | 23b0be4 | 2017-06-13 17:18:03 -0400 | [diff] [blame] | 1049 | depends on DEBUG_KERNEL |
Johannes Weiner | 6bf024e | 2015-12-17 17:19:57 -0500 | [diff] [blame] | 1050 | help |
| 1051 | This option enables a simple controller that exports |
Waiman Long | 23b0be4 | 2017-06-13 17:18:03 -0400 | [diff] [blame] | 1052 | debugging information about the cgroups framework. This |
| 1053 | controller is for control cgroup debugging only. Its |
| 1054 | interfaces are not stable. |
Johannes Weiner | 6bf024e | 2015-12-17 17:19:57 -0500 | [diff] [blame] | 1055 | |
| 1056 | Say N. |
| 1057 | |
Arnd Bergmann | 73b3514 | 2017-01-10 13:08:06 +0100 | [diff] [blame] | 1058 | config SOCK_CGROUP_DATA |
| 1059 | bool |
| 1060 | default n |
| 1061 | |
Li Zefan | 23964d2 | 2009-01-15 13:50:58 -0800 | [diff] [blame] | 1062 | endif # CGROUPS |
KAMEZAWA Hiroyuki | c077719 | 2009-01-07 18:07:57 -0800 | [diff] [blame] | 1063 | |
Daniel Lezcano | 8dd2a82 | 2010-10-27 15:34:38 -0700 | [diff] [blame] | 1064 | menuconfig NAMESPACES |
David Rientjes | 6a108a1 | 2011-01-20 14:44:16 -0800 | [diff] [blame] | 1065 | bool "Namespaces support" if EXPERT |
Iulia Manda | 2813893 | 2015-04-15 16:16:41 -0700 | [diff] [blame] | 1066 | depends on MULTIUSER |
David Rientjes | 6a108a1 | 2011-01-20 14:44:16 -0800 | [diff] [blame] | 1067 | default !EXPERT |
Pavel Emelyanov | c5289a6 | 2008-02-08 04:18:19 -0800 | [diff] [blame] | 1068 | help |
| 1069 | Provides the way to make tasks work with different objects using |
| 1070 | the same id. For example same IPC id may refer to different objects |
| 1071 | or same user id or pid may refer to different tasks when used in |
| 1072 | different namespaces. |
| 1073 | |
Daniel Lezcano | 8dd2a82 | 2010-10-27 15:34:38 -0700 | [diff] [blame] | 1074 | if NAMESPACES |
| 1075 | |
Pavel Emelyanov | 58bfdd6d | 2008-02-08 04:18:21 -0800 | [diff] [blame] | 1076 | config UTS_NS |
| 1077 | bool "UTS namespace" |
Daniel Lezcano | 17a6d44 | 2010-10-27 15:34:37 -0700 | [diff] [blame] | 1078 | default y |
Pavel Emelyanov | 58bfdd6d | 2008-02-08 04:18:21 -0800 | [diff] [blame] | 1079 | help |
| 1080 | In this namespace tasks see different info provided with the |
| 1081 | uname() system call |
| 1082 | |
Andrei Vagin | 769071a | 2019-11-12 01:26:52 +0000 | [diff] [blame] | 1083 | config TIME_NS |
| 1084 | bool "TIME namespace" |
Thomas Gleixner | 660fd04 | 2019-11-12 01:27:09 +0000 | [diff] [blame] | 1085 | depends on GENERIC_VDSO_TIME_NS |
Andrei Vagin | 769071a | 2019-11-12 01:26:52 +0000 | [diff] [blame] | 1086 | default y |
| 1087 | help |
| 1088 | In this namespace boottime and monotonic clocks can be set. |
| 1089 | The time will keep going with the same pace. |
| 1090 | |
Pavel Emelyanov | ae5e1b2 | 2008-02-08 04:18:22 -0800 | [diff] [blame] | 1091 | config IPC_NS |
| 1092 | bool "IPC namespace" |
Daniel Lezcano | 8dd2a82 | 2010-10-27 15:34:38 -0700 | [diff] [blame] | 1093 | depends on (SYSVIPC || POSIX_MQUEUE) |
Daniel Lezcano | 17a6d44 | 2010-10-27 15:34:37 -0700 | [diff] [blame] | 1094 | default y |
Pavel Emelyanov | ae5e1b2 | 2008-02-08 04:18:22 -0800 | [diff] [blame] | 1095 | help |
| 1096 | In this namespace tasks work with IPC ids which correspond to |
Serge E. Hallyn | 614b84c | 2009-04-06 19:01:08 -0700 | [diff] [blame] | 1097 | different IPC objects in different namespaces. |
Pavel Emelyanov | ae5e1b2 | 2008-02-08 04:18:22 -0800 | [diff] [blame] | 1098 | |
Pavel Emelyanov | aee16ce | 2008-02-08 04:18:23 -0800 | [diff] [blame] | 1099 | config USER_NS |
Kees Cook | 19c9239 | 2012-10-02 11:19:29 -0700 | [diff] [blame] | 1100 | bool "User namespace" |
Eric W. Biederman | 5673a94 | 2011-11-17 10:23:55 -0800 | [diff] [blame] | 1101 | default n |
Pavel Emelyanov | aee16ce | 2008-02-08 04:18:23 -0800 | [diff] [blame] | 1102 | help |
| 1103 | This allows containers, i.e. vservers, to use user namespaces |
| 1104 | to provide different user info for different servers. |
Eric W. Biederman | e11f0ae | 2013-01-25 16:48:31 -0800 | [diff] [blame] | 1105 | |
| 1106 | When user namespaces are enabled in the kernel it is |
Johannes Weiner | d886f4e | 2016-01-20 15:02:47 -0800 | [diff] [blame] | 1107 | recommended that the MEMCG option also be enabled and that |
| 1108 | user-space use the memory control groups to limit the amount |
| 1109 | of memory a memory unprivileged users can use. |
Eric W. Biederman | e11f0ae | 2013-01-25 16:48:31 -0800 | [diff] [blame] | 1110 | |
Pavel Emelyanov | aee16ce | 2008-02-08 04:18:23 -0800 | [diff] [blame] | 1111 | If unsure, say N. |
| 1112 | |
Pavel Emelyanov | 74bd59b | 2008-02-08 04:18:24 -0800 | [diff] [blame] | 1113 | config PID_NS |
Daniel Lezcano | 9bd38c2 | 2010-10-27 15:34:37 -0700 | [diff] [blame] | 1114 | bool "PID Namespaces" |
Daniel Lezcano | 17a6d44 | 2010-10-27 15:34:37 -0700 | [diff] [blame] | 1115 | default y |
Pavel Emelyanov | 74bd59b | 2008-02-08 04:18:24 -0800 | [diff] [blame] | 1116 | help |
Heikki Orsila | 12d2b8f | 2008-07-06 15:48:02 +0300 | [diff] [blame] | 1117 | Support process id namespaces. This allows having multiple |
Matt LaPlante | 692105b | 2009-01-26 11:12:25 +0100 | [diff] [blame] | 1118 | processes with the same pid as long as they are in different |
Pavel Emelyanov | 74bd59b | 2008-02-08 04:18:24 -0800 | [diff] [blame] | 1119 | pid namespaces. This is a building block of containers. |
| 1120 | |
Matt Helsley | d6eb633 | 2009-01-26 12:25:55 -0800 | [diff] [blame] | 1121 | config NET_NS |
| 1122 | bool "Network namespace" |
Daniel Lezcano | 8dd2a82 | 2010-10-27 15:34:38 -0700 | [diff] [blame] | 1123 | depends on NET |
Daniel Lezcano | 17a6d44 | 2010-10-27 15:34:37 -0700 | [diff] [blame] | 1124 | default y |
Matt Helsley | d6eb633 | 2009-01-26 12:25:55 -0800 | [diff] [blame] | 1125 | help |
| 1126 | Allow user space to create what appear to be multiple instances |
| 1127 | of the network stack. |
| 1128 | |
Daniel Lezcano | 8dd2a82 | 2010-10-27 15:34:38 -0700 | [diff] [blame] | 1129 | endif # NAMESPACES |
| 1130 | |
Adrian Reber | 5cb366b | 2018-08-21 22:01:17 -0700 | [diff] [blame] | 1131 | config CHECKPOINT_RESTORE |
| 1132 | bool "Checkpoint/restore support" |
| 1133 | select PROC_CHILDREN |
| 1134 | default n |
| 1135 | help |
| 1136 | Enables additional kernel features in a sake of checkpoint/restore. |
| 1137 | In particular it adds auxiliary prctl codes to setup process text, |
| 1138 | data and heap segment sizes, and a few additional /proc filesystem |
| 1139 | entries. |
| 1140 | |
| 1141 | If unsure, say N here. |
| 1142 | |
Mike Galbraith | 5091faa | 2010-11-30 14:18:03 +0100 | [diff] [blame] | 1143 | config SCHED_AUTOGROUP |
| 1144 | bool "Automatic process group scheduling" |
Mike Galbraith | 5091faa | 2010-11-30 14:18:03 +0100 | [diff] [blame] | 1145 | select CGROUPS |
| 1146 | select CGROUP_SCHED |
| 1147 | select FAIR_GROUP_SCHED |
| 1148 | help |
| 1149 | This option optimizes the scheduler for common desktop workloads by |
| 1150 | automatically creating and populating task groups. This separation |
| 1151 | of workloads isolates aggressive CPU burners (like build jobs) from |
| 1152 | desktop applications. Task group autogeneration is currently based |
| 1153 | upon task session. |
| 1154 | |
Daniel Lezcano | 7af37be | 2010-10-27 15:34:41 -0700 | [diff] [blame] | 1155 | config SYSFS_DEPRECATED |
Ferenc Wagner | 5d6a4ea | 2011-01-10 19:04:22 +0100 | [diff] [blame] | 1156 | bool "Enable deprecated sysfs features to support old userspace tools" |
Daniel Lezcano | 7af37be | 2010-10-27 15:34:41 -0700 | [diff] [blame] | 1157 | depends on SYSFS |
| 1158 | default n |
| 1159 | help |
| 1160 | This option adds code that switches the layout of the "block" class |
| 1161 | devices, to not show up in /sys/class/block/, but only in |
| 1162 | /sys/block/. |
| 1163 | |
| 1164 | This switch is only active when the sysfs.deprecated=1 boot option is |
| 1165 | passed or the SYSFS_DEPRECATED_V2 option is set. |
| 1166 | |
| 1167 | This option allows new kernels to run on old distributions and tools, |
| 1168 | which might get confused by /sys/class/block/. Since 2007/2008 all |
| 1169 | major distributions and tools handle this just fine. |
| 1170 | |
| 1171 | Recent distributions and userspace tools after 2009/2010 depend on |
| 1172 | the existence of /sys/class/block/, and will not work with this |
| 1173 | option enabled. |
| 1174 | |
| 1175 | Only if you are using a new kernel on an old distribution, you might |
| 1176 | need to say Y here. |
| 1177 | |
| 1178 | config SYSFS_DEPRECATED_V2 |
Ferenc Wagner | 5d6a4ea | 2011-01-10 19:04:22 +0100 | [diff] [blame] | 1179 | bool "Enable deprecated sysfs features by default" |
Daniel Lezcano | 7af37be | 2010-10-27 15:34:41 -0700 | [diff] [blame] | 1180 | default n |
| 1181 | depends on SYSFS |
| 1182 | depends on SYSFS_DEPRECATED |
| 1183 | help |
| 1184 | Enable deprecated sysfs by default. |
| 1185 | |
| 1186 | See the CONFIG_SYSFS_DEPRECATED option for more details about this |
| 1187 | option. |
| 1188 | |
| 1189 | Only if you are using a new kernel on an old distribution, you might |
| 1190 | need to say Y here. Even then, odds are you would not need it |
| 1191 | enabled, you can always pass the boot option if absolutely necessary. |
| 1192 | |
| 1193 | config RELAY |
| 1194 | bool "Kernel->user space relay support (formerly relayfs)" |
Peter Zijlstra | 26b5679 | 2016-10-11 13:54:33 -0700 | [diff] [blame] | 1195 | select IRQ_WORK |
Daniel Lezcano | 7af37be | 2010-10-27 15:34:41 -0700 | [diff] [blame] | 1196 | help |
| 1197 | This option enables support for relay interface support in |
| 1198 | certain file systems (such as debugfs). |
| 1199 | It is designed to provide an efficient mechanism for tools and |
| 1200 | facilities to relay large amounts of data from kernel space to |
| 1201 | user space. |
| 1202 | |
| 1203 | If unsure, say N. |
| 1204 | |
Dimitri Gorokhovik | f991633 | 2007-03-06 01:42:17 -0800 | [diff] [blame] | 1205 | config BLK_DEV_INITRD |
| 1206 | bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support" |
Dimitri Gorokhovik | f991633 | 2007-03-06 01:42:17 -0800 | [diff] [blame] | 1207 | help |
| 1208 | The initial RAM filesystem is a ramfs which is loaded by the |
| 1209 | boot loader (loadlin or lilo) and that is mounted as root |
| 1210 | before the normal boot procedure. It is typically used to |
| 1211 | load modules needed to mount the "real" root file system, |
Mauro Carvalho Chehab | 8c27ceff3 | 2016-10-18 10:12:27 -0200 | [diff] [blame] | 1212 | etc. See <file:Documentation/admin-guide/initrd.rst> for details. |
Dimitri Gorokhovik | f991633 | 2007-03-06 01:42:17 -0800 | [diff] [blame] | 1213 | |
| 1214 | If RAM disk support (BLK_DEV_RAM) is also included, this |
| 1215 | also enables initial RAM disk (initrd) support and adds |
| 1216 | 15 Kbytes (more on some other architectures) to the kernel size. |
| 1217 | |
| 1218 | If unsure say Y. |
| 1219 | |
Jean-Paul Saman | c33df4e | 2007-02-10 01:44:43 -0800 | [diff] [blame] | 1220 | if BLK_DEV_INITRD |
| 1221 | |
Sam Ravnborg | dbec486 | 2005-08-10 20:44:50 +0200 | [diff] [blame] | 1222 | source "usr/Kconfig" |
| 1223 | |
Jean-Paul Saman | c33df4e | 2007-02-10 01:44:43 -0800 | [diff] [blame] | 1224 | endif |
| 1225 | |
Arnd Bergmann | 877417e | 2016-04-25 17:35:27 +0200 | [diff] [blame] | 1226 | choice |
| 1227 | prompt "Compiler optimization level" |
Ulf Magnusson | 2cc3ce2 | 2017-10-04 01:53:26 +0200 | [diff] [blame] | 1228 | default CC_OPTIMIZE_FOR_PERFORMANCE |
Arnd Bergmann | 877417e | 2016-04-25 17:35:27 +0200 | [diff] [blame] | 1229 | |
| 1230 | config CC_OPTIMIZE_FOR_PERFORMANCE |
Masahiro Yamada | 15f5db6 | 2019-08-21 02:09:40 +0900 | [diff] [blame] | 1231 | bool "Optimize for performance (-O2)" |
Arnd Bergmann | 877417e | 2016-04-25 17:35:27 +0200 | [diff] [blame] | 1232 | help |
| 1233 | This is the default optimization level for the kernel, building |
| 1234 | with the "-O2" compiler flag for best performance and most |
| 1235 | helpful compile-time warnings. |
| 1236 | |
Masahiro Yamada | 15f5db6 | 2019-08-21 02:09:40 +0900 | [diff] [blame] | 1237 | config CC_OPTIMIZE_FOR_PERFORMANCE_O3 |
| 1238 | bool "Optimize more for performance (-O3)" |
| 1239 | depends on ARC |
Masahiro Yamada | b303c6d | 2019-02-21 13:13:38 +0900 | [diff] [blame] | 1240 | imply CC_DISABLE_WARN_MAYBE_UNINITIALIZED # avoid false positives |
Linus Torvalds | c45b4f1 | 2005-12-14 18:52:21 -0800 | [diff] [blame] | 1241 | help |
Masahiro Yamada | 15f5db6 | 2019-08-21 02:09:40 +0900 | [diff] [blame] | 1242 | Choosing this option will pass "-O3" to your compiler to optimize |
| 1243 | the kernel yet more for performance. |
Linus Torvalds | c45b4f1 | 2005-12-14 18:52:21 -0800 | [diff] [blame] | 1244 | |
Nicholas Piggin | 5d20ee3 | 2018-05-09 23:00:00 +1000 | [diff] [blame] | 1245 | config CC_OPTIMIZE_FOR_SIZE |
Masahiro Yamada | 15f5db6 | 2019-08-21 02:09:40 +0900 | [diff] [blame] | 1246 | bool "Optimize for size (-Os)" |
Nicholas Piggin | 5d20ee3 | 2018-05-09 23:00:00 +1000 | [diff] [blame] | 1247 | imply CC_DISABLE_WARN_MAYBE_UNINITIALIZED # avoid false positives |
| 1248 | help |
Masahiro Yamada | ce3b487 | 2019-08-21 02:09:39 +0900 | [diff] [blame] | 1249 | Choosing this option will pass "-Os" to your compiler resulting |
| 1250 | in a smaller kernel. |
Linus Torvalds | c45b4f1 | 2005-12-14 18:52:21 -0800 | [diff] [blame] | 1251 | |
Arnd Bergmann | 877417e | 2016-04-25 17:35:27 +0200 | [diff] [blame] | 1252 | endchoice |
| 1253 | |
Nicholas Piggin | 5d20ee3 | 2018-05-09 23:00:00 +1000 | [diff] [blame] | 1254 | config HAVE_LD_DEAD_CODE_DATA_ELIMINATION |
| 1255 | bool |
| 1256 | help |
| 1257 | This requires that the arch annotates or otherwise protects |
| 1258 | its external entry points from being discarded. Linker scripts |
| 1259 | must also merge .text.*, .data.*, and .bss.* correctly into |
| 1260 | output sections. Care must be taken not to pull in unrelated |
| 1261 | sections (e.g., '.text.init'). Typically '.' in section names |
| 1262 | is used to distinguish them from label names / C identifiers. |
| 1263 | |
| 1264 | config LD_DEAD_CODE_DATA_ELIMINATION |
| 1265 | bool "Dead code and data elimination (EXPERIMENTAL)" |
| 1266 | depends on HAVE_LD_DEAD_CODE_DATA_ELIMINATION |
| 1267 | depends on EXPERT |
Paul Burton | 16fd20a | 2019-01-11 19:06:44 +0000 | [diff] [blame] | 1268 | depends on !(FUNCTION_TRACER && CC_IS_GCC && GCC_VERSION < 40800) |
Masahiro Yamada | e85d1d6 | 2018-08-22 22:51:09 +0900 | [diff] [blame] | 1269 | depends on $(cc-option,-ffunction-sections -fdata-sections) |
| 1270 | depends on $(ld-option,--gc-sections) |
Nicholas Piggin | 5d20ee3 | 2018-05-09 23:00:00 +1000 | [diff] [blame] | 1271 | help |
Masahiro Yamada | 8b9d271 | 2018-06-24 01:41:51 +0900 | [diff] [blame] | 1272 | Enable this if you want to do dead code and data elimination with |
| 1273 | the linker by compiling with -ffunction-sections -fdata-sections, |
| 1274 | and linking with --gc-sections. |
Nicholas Piggin | 5d20ee3 | 2018-05-09 23:00:00 +1000 | [diff] [blame] | 1275 | |
| 1276 | This can reduce on disk and in-memory size of the kernel |
| 1277 | code and static data, particularly for small configs and |
| 1278 | on small systems. This has the possibility of introducing |
| 1279 | silently broken kernel if the required annotations are not |
| 1280 | present. This option is not well tested yet, so use at your |
| 1281 | own risk. |
| 1282 | |
Randy Dunlap | 0847062 | 2006-09-30 23:28:13 -0700 | [diff] [blame] | 1283 | config SYSCTL |
| 1284 | bool |
| 1285 | |
Mike Frysinger | 657a520 | 2013-04-30 15:28:45 -0700 | [diff] [blame] | 1286 | config HAVE_UID16 |
| 1287 | bool |
| 1288 | |
| 1289 | config SYSCTL_EXCEPTION_TRACE |
| 1290 | bool |
| 1291 | help |
| 1292 | Enable support for /proc/sys/debug/exception-trace. |
| 1293 | |
| 1294 | config SYSCTL_ARCH_UNALIGN_NO_WARN |
| 1295 | bool |
| 1296 | help |
| 1297 | Enable support for /proc/sys/kernel/ignore-unaligned-usertrap |
| 1298 | Allows arch to define/use @no_unaligned_warning to possibly warn |
| 1299 | about unaligned access emulation going on under the hood. |
| 1300 | |
| 1301 | config SYSCTL_ARCH_UNALIGN_ALLOW |
| 1302 | bool |
| 1303 | help |
| 1304 | Enable support for /proc/sys/kernel/unaligned-trap |
| 1305 | Allows arches to define/use @unaligned_enabled to runtime toggle |
| 1306 | the unaligned access emulation. |
| 1307 | see arch/parisc/kernel/unaligned.c for reference |
| 1308 | |
Mike Frysinger | 657a520 | 2013-04-30 15:28:45 -0700 | [diff] [blame] | 1309 | config HAVE_PCSPKR_PLATFORM |
| 1310 | bool |
| 1311 | |
Alexei Starovoitov | f89b775 | 2014-10-23 18:41:08 -0700 | [diff] [blame] | 1312 | # interpreter that classic socket filters depend on |
| 1313 | config BPF |
| 1314 | bool |
| 1315 | |
David Rientjes | 6a108a1 | 2011-01-20 14:44:16 -0800 | [diff] [blame] | 1316 | menuconfig EXPERT |
| 1317 | bool "Configure standard kernel features (expert users)" |
Josh Triplett | f505c55 | 2011-06-05 18:23:58 -0700 | [diff] [blame] | 1318 | # Unhide debug options, to make the on-by-default options visible |
| 1319 | select DEBUG_KERNEL |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1320 | help |
| 1321 | This option allows certain base kernel options and settings |
Krzysztof Kozlowski | e8cf4e9 | 2019-12-04 16:52:28 -0800 | [diff] [blame] | 1322 | to be disabled or tweaked. This is for specialized |
| 1323 | environments which can tolerate a "non-standard" kernel. |
| 1324 | Only use this if you really know what you are doing. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1325 | |
Chuck Ebbert | ae81f9e | 2006-09-16 12:15:53 -0700 | [diff] [blame] | 1326 | config UID16 |
David Rientjes | 6a108a1 | 2011-01-20 14:44:16 -0800 | [diff] [blame] | 1327 | bool "Enable 16-bit UID system calls" if EXPERT |
Iulia Manda | 2813893 | 2015-04-15 16:16:41 -0700 | [diff] [blame] | 1328 | depends on HAVE_UID16 && MULTIUSER |
Chuck Ebbert | ae81f9e | 2006-09-16 12:15:53 -0700 | [diff] [blame] | 1329 | default y |
| 1330 | help |
| 1331 | This enables the legacy 16-bit UID syscall wrappers. |
| 1332 | |
Iulia Manda | 2813893 | 2015-04-15 16:16:41 -0700 | [diff] [blame] | 1333 | config MULTIUSER |
| 1334 | bool "Multiple users, groups and capabilities support" if EXPERT |
| 1335 | default y |
| 1336 | help |
| 1337 | This option enables support for non-root users, groups and |
| 1338 | capabilities. |
| 1339 | |
| 1340 | If you say N here, all processes will run with UID 0, GID 0, and all |
| 1341 | possible capabilities. Saying N here also compiles out support for |
| 1342 | system calls related to UIDs, GIDs, and capabilities, such as setuid, |
| 1343 | setgid, and capset. |
| 1344 | |
| 1345 | If unsure, say Y here. |
| 1346 | |
Fabian Frederick | f618776 | 2014-06-04 16:11:12 -0700 | [diff] [blame] | 1347 | config SGETMASK_SYSCALL |
| 1348 | bool "sgetmask/ssetmask syscalls support" if EXPERT |
Arnd Bergmann | a687a53 | 2018-03-07 23:30:54 +0100 | [diff] [blame] | 1349 | def_bool PARISC || M68K || PPC || MIPS || X86 || SPARC || MICROBLAZE || SUPERH |
Fabian Frederick | f618776 | 2014-06-04 16:11:12 -0700 | [diff] [blame] | 1350 | ---help--- |
| 1351 | sys_sgetmask and sys_ssetmask are obsolete system calls |
| 1352 | no longer supported in libc but still enabled by default in some |
| 1353 | architectures. |
| 1354 | |
| 1355 | If unsure, leave the default option here. |
| 1356 | |
Fabian Frederick | 6af9f7b | 2014-04-03 14:48:25 -0700 | [diff] [blame] | 1357 | config SYSFS_SYSCALL |
| 1358 | bool "Sysfs syscall support" if EXPERT |
| 1359 | default y |
| 1360 | ---help--- |
| 1361 | sys_sysfs is an obsolete system call no longer supported in libc. |
| 1362 | Note that disabling this option is more secure but might break |
| 1363 | compatibility with some systems. |
| 1364 | |
| 1365 | If unsure say Y here. |
| 1366 | |
Randy Dunlap | d1b069f | 2017-11-17 15:31:47 -0800 | [diff] [blame] | 1367 | config FHANDLE |
| 1368 | bool "open by fhandle syscalls" if EXPERT |
| 1369 | select EXPORTFS |
| 1370 | default y |
| 1371 | help |
| 1372 | If you say Y here, a user level program will be able to map |
| 1373 | file names to handle and then later use the handle for |
| 1374 | different file system operations. This is useful in implementing |
| 1375 | userspace file servers, which now track files using handles instead |
| 1376 | of names. The handle would remain the same even if file names |
| 1377 | get renamed. Enables open_by_handle_at(2) and name_to_handle_at(2) |
| 1378 | syscalls. |
| 1379 | |
Nicolas Pitre | baa73d9 | 2016-11-11 00:10:10 -0500 | [diff] [blame] | 1380 | config POSIX_TIMERS |
| 1381 | bool "Posix Clocks & timers" if EXPERT |
| 1382 | default y |
| 1383 | help |
| 1384 | This includes native support for POSIX timers to the kernel. |
| 1385 | Some embedded systems have no use for them and therefore they |
| 1386 | can be configured out to reduce the size of the kernel image. |
| 1387 | |
| 1388 | When this option is disabled, the following syscalls won't be |
| 1389 | available: timer_create, timer_gettime: timer_getoverrun, |
| 1390 | timer_settime, timer_delete, clock_adjtime, getitimer, |
| 1391 | setitimer, alarm. Furthermore, the clock_settime, clock_gettime, |
| 1392 | clock_getres and clock_nanosleep syscalls will be limited to |
| 1393 | CLOCK_REALTIME, CLOCK_MONOTONIC and CLOCK_BOOTTIME only. |
| 1394 | |
| 1395 | If unsure say y. |
| 1396 | |
Matt Mackall | d59745c | 2005-05-01 08:59:02 -0700 | [diff] [blame] | 1397 | config PRINTK |
| 1398 | default y |
David Rientjes | 6a108a1 | 2011-01-20 14:44:16 -0800 | [diff] [blame] | 1399 | bool "Enable support for printk" if EXPERT |
Frederic Weisbecker | 74876a9 | 2012-10-12 18:00:23 +0200 | [diff] [blame] | 1400 | select IRQ_WORK |
Matt Mackall | d59745c | 2005-05-01 08:59:02 -0700 | [diff] [blame] | 1401 | help |
| 1402 | This option enables normal printk support. Removing it |
| 1403 | eliminates most of the message strings from the kernel image |
| 1404 | and makes the kernel more or less silent. As this makes it |
| 1405 | very difficult to diagnose system problems, saying N here is |
| 1406 | strongly discouraged. |
| 1407 | |
Petr Mladek | 42a0bb3 | 2016-05-20 17:00:33 -0700 | [diff] [blame] | 1408 | config PRINTK_NMI |
| 1409 | def_bool y |
| 1410 | depends on PRINTK |
| 1411 | depends on HAVE_NMI |
| 1412 | |
Matt Mackall | c8538a7 | 2005-05-01 08:59:01 -0700 | [diff] [blame] | 1413 | config BUG |
David Rientjes | 6a108a1 | 2011-01-20 14:44:16 -0800 | [diff] [blame] | 1414 | bool "BUG() support" if EXPERT |
Matt Mackall | c8538a7 | 2005-05-01 08:59:01 -0700 | [diff] [blame] | 1415 | default y |
| 1416 | help |
Krzysztof Kozlowski | e8cf4e9 | 2019-12-04 16:52:28 -0800 | [diff] [blame] | 1417 | Disabling this option eliminates support for BUG and WARN, reducing |
| 1418 | the size of your kernel image and potentially quietly ignoring |
| 1419 | numerous fatal conditions. You should only consider disabling this |
| 1420 | option for embedded systems with no facilities for reporting errors. |
| 1421 | Just say Y. |
Matt Mackall | c8538a7 | 2005-05-01 08:59:01 -0700 | [diff] [blame] | 1422 | |
Matt Mackall | 708e9a7 | 2006-01-08 01:05:25 -0800 | [diff] [blame] | 1423 | config ELF_CORE |
Alex Kelly | 046d662 | 2012-10-04 17:15:23 -0700 | [diff] [blame] | 1424 | depends on COREDUMP |
Matt Mackall | 708e9a7 | 2006-01-08 01:05:25 -0800 | [diff] [blame] | 1425 | default y |
David Rientjes | 6a108a1 | 2011-01-20 14:44:16 -0800 | [diff] [blame] | 1426 | bool "Enable ELF core dumps" if EXPERT |
Matt Mackall | 708e9a7 | 2006-01-08 01:05:25 -0800 | [diff] [blame] | 1427 | help |
| 1428 | Enable support for generating core dumps. Disabling saves about 4k. |
| 1429 | |
Ralf Baechle | 8761f1a | 2011-06-01 19:05:09 +0100 | [diff] [blame] | 1430 | |
Stas Sergeev | e5e1d3c | 2008-05-07 12:39:56 +0200 | [diff] [blame] | 1431 | config PCSPKR_PLATFORM |
David Rientjes | 6a108a1 | 2011-01-20 14:44:16 -0800 | [diff] [blame] | 1432 | bool "Enable PC-Speaker support" if EXPERT |
Ralf Baechle | 8761f1a | 2011-06-01 19:05:09 +0100 | [diff] [blame] | 1433 | depends on HAVE_PCSPKR_PLATFORM |
Ralf Baechle | 15f304b | 2011-06-01 19:04:59 +0100 | [diff] [blame] | 1434 | select I8253_LOCK |
Stas Sergeev | e5e1d3c | 2008-05-07 12:39:56 +0200 | [diff] [blame] | 1435 | default y |
| 1436 | help |
Krzysztof Kozlowski | e8cf4e9 | 2019-12-04 16:52:28 -0800 | [diff] [blame] | 1437 | This option allows to disable the internal PC-Speaker |
| 1438 | support, saving some memory. |
Stas Sergeev | e5e1d3c | 2008-05-07 12:39:56 +0200 | [diff] [blame] | 1439 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1440 | config BASE_FULL |
| 1441 | default y |
David Rientjes | 6a108a1 | 2011-01-20 14:44:16 -0800 | [diff] [blame] | 1442 | bool "Enable full-sized data structures for core" if EXPERT |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1443 | help |
| 1444 | Disabling this option reduces the size of miscellaneous core |
| 1445 | kernel data structures. This saves memory on small machines, |
| 1446 | but may reduce performance. |
| 1447 | |
| 1448 | config FUTEX |
David Rientjes | 6a108a1 | 2011-01-20 14:44:16 -0800 | [diff] [blame] | 1449 | bool "Enable futex support" if EXPERT |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1450 | default y |
Nicolas Pitre | bc2eecd | 2017-08-01 00:31:32 -0400 | [diff] [blame] | 1451 | imply RT_MUTEXES |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1452 | help |
| 1453 | Disabling this option will cause the kernel to be built without |
| 1454 | support for "fast userspace mutexes". The resulting kernel may not |
| 1455 | run glibc-based applications correctly. |
| 1456 | |
Nicolas Pitre | bc2eecd | 2017-08-01 00:31:32 -0400 | [diff] [blame] | 1457 | config FUTEX_PI |
| 1458 | bool |
| 1459 | depends on FUTEX && RT_MUTEXES |
| 1460 | default y |
| 1461 | |
Heiko Carstens | 03b8c7b | 2014-03-02 13:09:47 +0100 | [diff] [blame] | 1462 | config HAVE_FUTEX_CMPXCHG |
| 1463 | bool |
Josh Triplett | 62b4d20 | 2014-10-03 16:19:24 -0700 | [diff] [blame] | 1464 | depends on FUTEX |
Heiko Carstens | 03b8c7b | 2014-03-02 13:09:47 +0100 | [diff] [blame] | 1465 | help |
| 1466 | Architectures should select this if futex_atomic_cmpxchg_inatomic() |
| 1467 | is implemented and always working. This removes a couple of runtime |
| 1468 | checks. |
| 1469 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1470 | config EPOLL |
David Rientjes | 6a108a1 | 2011-01-20 14:44:16 -0800 | [diff] [blame] | 1471 | bool "Enable eventpoll support" if EXPERT |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1472 | default y |
| 1473 | help |
| 1474 | Disabling this option will cause the kernel to be built without |
| 1475 | support for epoll family of system calls. |
| 1476 | |
Davide Libenzi | fba2afa | 2007-05-10 22:23:13 -0700 | [diff] [blame] | 1477 | config SIGNALFD |
David Rientjes | 6a108a1 | 2011-01-20 14:44:16 -0800 | [diff] [blame] | 1478 | bool "Enable signalfd() system call" if EXPERT |
Davide Libenzi | fba2afa | 2007-05-10 22:23:13 -0700 | [diff] [blame] | 1479 | default y |
| 1480 | help |
| 1481 | Enable the signalfd() system call that allows to receive signals |
| 1482 | on a file descriptor. |
| 1483 | |
| 1484 | If unsure, say Y. |
| 1485 | |
Davide Libenzi | b215e28 | 2007-05-10 22:23:16 -0700 | [diff] [blame] | 1486 | config TIMERFD |
David Rientjes | 6a108a1 | 2011-01-20 14:44:16 -0800 | [diff] [blame] | 1487 | bool "Enable timerfd() system call" if EXPERT |
Davide Libenzi | b215e28 | 2007-05-10 22:23:16 -0700 | [diff] [blame] | 1488 | default y |
| 1489 | help |
| 1490 | Enable the timerfd() system call that allows to receive timer |
| 1491 | events on a file descriptor. |
| 1492 | |
| 1493 | If unsure, say Y. |
| 1494 | |
Davide Libenzi | e1ad746 | 2007-05-10 22:23:19 -0700 | [diff] [blame] | 1495 | config EVENTFD |
David Rientjes | 6a108a1 | 2011-01-20 14:44:16 -0800 | [diff] [blame] | 1496 | bool "Enable eventfd() system call" if EXPERT |
Davide Libenzi | e1ad746 | 2007-05-10 22:23:19 -0700 | [diff] [blame] | 1497 | default y |
| 1498 | help |
| 1499 | Enable the eventfd() system call that allows to receive both |
| 1500 | kernel notification (ie. KAIO) or userspace notifications. |
| 1501 | |
| 1502 | If unsure, say Y. |
| 1503 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1504 | config SHMEM |
David Rientjes | 6a108a1 | 2011-01-20 14:44:16 -0800 | [diff] [blame] | 1505 | bool "Use full shmem filesystem" if EXPERT |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1506 | default y |
| 1507 | depends on MMU |
| 1508 | help |
| 1509 | The shmem is an internal filesystem used to manage shared memory. |
| 1510 | It is backed by swap and manages resource limits. It is also exported |
| 1511 | to userspace as tmpfs if TMPFS is enabled. Disabling this |
| 1512 | option replaces shmem and tmpfs with the much simpler ramfs code, |
| 1513 | which may be appropriate on small systems without swap. |
| 1514 | |
Thomas Petazzoni | ebf3f09 | 2008-10-15 22:05:12 -0700 | [diff] [blame] | 1515 | config AIO |
David Rientjes | 6a108a1 | 2011-01-20 14:44:16 -0800 | [diff] [blame] | 1516 | bool "Enable AIO support" if EXPERT |
Thomas Petazzoni | ebf3f09 | 2008-10-15 22:05:12 -0700 | [diff] [blame] | 1517 | default y |
| 1518 | help |
| 1519 | This option enables POSIX asynchronous I/O which may by used |
Mike Frysinger | 657a520 | 2013-04-30 15:28:45 -0700 | [diff] [blame] | 1520 | by some high performance threaded applications. Disabling |
| 1521 | this option saves about 7k. |
| 1522 | |
Jens Axboe | 2b188cc | 2019-01-07 10:46:33 -0700 | [diff] [blame] | 1523 | config IO_URING |
| 1524 | bool "Enable IO uring support" if EXPERT |
| 1525 | select ANON_INODES |
Jens Axboe | 561fb04 | 2019-10-24 07:25:42 -0600 | [diff] [blame] | 1526 | select IO_WQ |
Jens Axboe | 2b188cc | 2019-01-07 10:46:33 -0700 | [diff] [blame] | 1527 | default y |
| 1528 | help |
| 1529 | This option enables support for the io_uring interface, enabling |
| 1530 | applications to submit and complete IO through submission and |
| 1531 | completion rings that are shared between the kernel and application. |
| 1532 | |
Josh Triplett | d3ac21c | 2014-08-17 19:41:09 -0500 | [diff] [blame] | 1533 | config ADVISE_SYSCALLS |
| 1534 | bool "Enable madvise/fadvise syscalls" if EXPERT |
| 1535 | default y |
| 1536 | help |
| 1537 | This option enables the madvise and fadvise syscalls, used by |
| 1538 | applications to advise the kernel about their future memory or file |
| 1539 | usage, improving performance. If building an embedded system where no |
| 1540 | applications use these syscalls, you can disable this option to save |
| 1541 | space. |
| 1542 | |
Mathieu Desnoyers | 5b25b13 | 2015-09-11 13:07:39 -0700 | [diff] [blame] | 1543 | config MEMBARRIER |
| 1544 | bool "Enable membarrier() system call" if EXPERT |
| 1545 | default y |
| 1546 | help |
| 1547 | Enable the membarrier() system call that allows issuing memory |
| 1548 | barriers across all running threads, which can be used to distribute |
| 1549 | the cost of user-space memory barriers asymmetrically by transforming |
| 1550 | pairs of memory barriers into pairs consisting of membarrier() and a |
| 1551 | compiler barrier. |
| 1552 | |
| 1553 | If unsure, say Y. |
| 1554 | |
Randy Dunlap | d1b069f | 2017-11-17 15:31:47 -0800 | [diff] [blame] | 1555 | config KALLSYMS |
Krzysztof Kozlowski | e8cf4e9 | 2019-12-04 16:52:28 -0800 | [diff] [blame] | 1556 | bool "Load all symbols for debugging/ksymoops" if EXPERT |
| 1557 | default y |
| 1558 | help |
| 1559 | Say Y here to let the kernel print out symbolic crash information and |
| 1560 | symbolic stack backtraces. This increases the size of the kernel |
| 1561 | somewhat, as all symbols have to be loaded into the kernel image. |
Randy Dunlap | d1b069f | 2017-11-17 15:31:47 -0800 | [diff] [blame] | 1562 | |
| 1563 | config KALLSYMS_ALL |
| 1564 | bool "Include all symbols in kallsyms" |
| 1565 | depends on DEBUG_KERNEL && KALLSYMS |
| 1566 | help |
Krzysztof Kozlowski | e8cf4e9 | 2019-12-04 16:52:28 -0800 | [diff] [blame] | 1567 | Normally kallsyms only contains the symbols of functions for nicer |
| 1568 | OOPS messages and backtraces (i.e., symbols from the text and inittext |
| 1569 | sections). This is sufficient for most cases. And only in very rare |
| 1570 | cases (e.g., when a debugger is used) all symbols are required (e.g., |
| 1571 | names of variables from the data sections, etc). |
Randy Dunlap | d1b069f | 2017-11-17 15:31:47 -0800 | [diff] [blame] | 1572 | |
Krzysztof Kozlowski | e8cf4e9 | 2019-12-04 16:52:28 -0800 | [diff] [blame] | 1573 | This option makes sure that all symbols are loaded into the kernel |
| 1574 | image (i.e., symbols from all sections) in cost of increased kernel |
| 1575 | size (depending on the kernel configuration, it may be 300KiB or |
| 1576 | something like this). |
Randy Dunlap | d1b069f | 2017-11-17 15:31:47 -0800 | [diff] [blame] | 1577 | |
Krzysztof Kozlowski | e8cf4e9 | 2019-12-04 16:52:28 -0800 | [diff] [blame] | 1578 | Say N unless you really need all symbols. |
Randy Dunlap | d1b069f | 2017-11-17 15:31:47 -0800 | [diff] [blame] | 1579 | |
| 1580 | config KALLSYMS_ABSOLUTE_PERCPU |
| 1581 | bool |
| 1582 | depends on KALLSYMS |
| 1583 | default X86_64 && SMP |
| 1584 | |
| 1585 | config KALLSYMS_BASE_RELATIVE |
| 1586 | bool |
| 1587 | depends on KALLSYMS |
Arnd Bergmann | a687a53 | 2018-03-07 23:30:54 +0100 | [diff] [blame] | 1588 | default !IA64 |
Randy Dunlap | d1b069f | 2017-11-17 15:31:47 -0800 | [diff] [blame] | 1589 | help |
| 1590 | Instead of emitting them as absolute values in the native word size, |
| 1591 | emit the symbol references in the kallsyms table as 32-bit entries, |
| 1592 | each containing a relative value in the range [base, base + U32_MAX] |
| 1593 | or, when KALLSYMS_ABSOLUTE_PERCPU is in effect, each containing either |
| 1594 | an absolute value in the range [0, S32_MAX] or a relative value in the |
| 1595 | range [base, base + S32_MAX], where base is the lowest relative symbol |
| 1596 | address encountered in the image. |
| 1597 | |
| 1598 | On 64-bit builds, this reduces the size of the address table by 50%, |
| 1599 | but more importantly, it results in entries whose values are build |
| 1600 | time constants, and no relocation pass is required at runtime to fix |
| 1601 | up the entries based on the runtime load address of the kernel. |
| 1602 | |
| 1603 | # end of the "standard kernel features (expert users)" menu |
| 1604 | |
| 1605 | # syscall, maps, verifier |
| 1606 | config BPF_SYSCALL |
| 1607 | bool "Enable bpf() system call" |
Randy Dunlap | d1b069f | 2017-11-17 15:31:47 -0800 | [diff] [blame] | 1608 | select BPF |
Song Liu | bae77c5 | 2018-05-07 10:50:48 -0700 | [diff] [blame] | 1609 | select IRQ_WORK |
Randy Dunlap | d1b069f | 2017-11-17 15:31:47 -0800 | [diff] [blame] | 1610 | default n |
| 1611 | help |
| 1612 | Enable the bpf() system call that allows to manipulate eBPF |
| 1613 | programs and maps via file descriptors. |
| 1614 | |
Alexei Starovoitov | 290af86 | 2018-01-09 10:04:29 -0800 | [diff] [blame] | 1615 | config BPF_JIT_ALWAYS_ON |
| 1616 | bool "Permanently enable BPF JIT and remove BPF interpreter" |
| 1617 | depends on BPF_SYSCALL && HAVE_EBPF_JIT && BPF_JIT |
| 1618 | help |
| 1619 | Enables BPF JIT and removes BPF interpreter to avoid |
| 1620 | speculative execution of BPF instructions by the interpreter |
| 1621 | |
Randy Dunlap | d1b069f | 2017-11-17 15:31:47 -0800 | [diff] [blame] | 1622 | config USERFAULTFD |
| 1623 | bool "Enable userfaultfd() system call" |
Randy Dunlap | d1b069f | 2017-11-17 15:31:47 -0800 | [diff] [blame] | 1624 | depends on MMU |
| 1625 | help |
| 1626 | Enable the userfaultfd() system call that allows to intercept and |
| 1627 | handle page faults in userland. |
| 1628 | |
Mathieu Desnoyers | 3ccfebe | 2018-01-29 15:20:11 -0500 | [diff] [blame] | 1629 | config ARCH_HAS_MEMBARRIER_CALLBACKS |
| 1630 | bool |
| 1631 | |
Mathieu Desnoyers | 70216e1 | 2018-01-29 15:20:17 -0500 | [diff] [blame] | 1632 | config ARCH_HAS_MEMBARRIER_SYNC_CORE |
| 1633 | bool |
| 1634 | |
Mathieu Desnoyers | d7822b1 | 2018-06-02 08:43:54 -0400 | [diff] [blame] | 1635 | config RSEQ |
| 1636 | bool "Enable rseq() system call" if EXPERT |
| 1637 | default y |
| 1638 | depends on HAVE_RSEQ |
| 1639 | select MEMBARRIER |
| 1640 | help |
| 1641 | Enable the restartable sequences system call. It provides a |
| 1642 | user-space cache for the current CPU number value, which |
| 1643 | speeds up getting the current CPU number from user-space, |
| 1644 | as well as an ABI to speed up user-space operations on |
| 1645 | per-CPU data. |
| 1646 | |
| 1647 | If unsure, say Y. |
| 1648 | |
| 1649 | config DEBUG_RSEQ |
| 1650 | default n |
| 1651 | bool "Enabled debugging of rseq() system call" if EXPERT |
| 1652 | depends on RSEQ && DEBUG_KERNEL |
| 1653 | help |
| 1654 | Enable extra debugging checks for the rseq system call. |
| 1655 | |
| 1656 | If unsure, say N. |
| 1657 | |
Randy Dunlap | 6befe5f | 2011-04-26 12:33:21 -0700 | [diff] [blame] | 1658 | config EMBEDDED |
| 1659 | bool "Embedded system" |
Josh Triplett | 5d2acfc | 2014-04-07 15:39:09 -0700 | [diff] [blame] | 1660 | option allnoconfig_y |
Randy Dunlap | 6befe5f | 2011-04-26 12:33:21 -0700 | [diff] [blame] | 1661 | select EXPERT |
| 1662 | help |
| 1663 | This option should be enabled if compiling the kernel for |
| 1664 | an embedded system so certain expert options are available |
| 1665 | for configuration. |
| 1666 | |
Ingo Molnar | cdd6c48 | 2009-09-21 12:02:48 +0200 | [diff] [blame] | 1667 | config HAVE_PERF_EVENTS |
Thomas Gleixner | 0793a61 | 2008-12-04 20:12:29 +0100 | [diff] [blame] | 1668 | bool |
Mike Frysinger | 018df72 | 2009-06-12 13:17:43 -0400 | [diff] [blame] | 1669 | help |
| 1670 | See tools/perf/design.txt for details. |
Thomas Gleixner | 0793a61 | 2008-12-04 20:12:29 +0100 | [diff] [blame] | 1671 | |
Peter Zijlstra | 906010b | 2009-09-21 16:08:49 +0200 | [diff] [blame] | 1672 | config PERF_USE_VMALLOC |
| 1673 | bool |
| 1674 | help |
| 1675 | See tools/perf/design.txt for details |
| 1676 | |
William Breathitt Gray | ad90a3d | 2017-01-10 13:50:54 -0500 | [diff] [blame] | 1677 | config PC104 |
William Breathitt Gray | 424529f | 2017-12-29 15:14:59 -0500 | [diff] [blame] | 1678 | bool "PC/104 support" if EXPERT |
William Breathitt Gray | ad90a3d | 2017-01-10 13:50:54 -0500 | [diff] [blame] | 1679 | help |
| 1680 | Expose PC/104 form factor device drivers and options available for |
| 1681 | selection and configuration. Enable this option if your target |
| 1682 | machine has a PC/104 bus. |
| 1683 | |
Ingo Molnar | 57c0c15 | 2009-09-21 12:20:38 +0200 | [diff] [blame] | 1684 | menu "Kernel Performance Events And Counters" |
Thomas Gleixner | 0793a61 | 2008-12-04 20:12:29 +0100 | [diff] [blame] | 1685 | |
Ingo Molnar | cdd6c48 | 2009-09-21 12:02:48 +0200 | [diff] [blame] | 1686 | config PERF_EVENTS |
Ingo Molnar | 57c0c15 | 2009-09-21 12:20:38 +0200 | [diff] [blame] | 1687 | bool "Kernel performance events and counters" |
Robert Richter | 392d65a | 2012-04-05 18:24:44 +0200 | [diff] [blame] | 1688 | default y if PROFILING |
Ingo Molnar | cdd6c48 | 2009-09-21 12:02:48 +0200 | [diff] [blame] | 1689 | depends on HAVE_PERF_EVENTS |
Peter Zijlstra | e360adb | 2010-10-14 14:01:34 +0800 | [diff] [blame] | 1690 | select IRQ_WORK |
Pranith Kumar | 83fe27e | 2014-12-05 11:24:45 -0500 | [diff] [blame] | 1691 | select SRCU |
Thomas Gleixner | 0793a61 | 2008-12-04 20:12:29 +0100 | [diff] [blame] | 1692 | help |
Ingo Molnar | 57c0c15 | 2009-09-21 12:20:38 +0200 | [diff] [blame] | 1693 | Enable kernel support for various performance events provided |
| 1694 | by software and hardware. |
Thomas Gleixner | 0793a61 | 2008-12-04 20:12:29 +0100 | [diff] [blame] | 1695 | |
Thadeu Lima de Souza Cascardo | dd77038 | 2009-10-30 19:32:25 -0200 | [diff] [blame] | 1696 | Software events are supported either built-in or via the |
Ingo Molnar | 57c0c15 | 2009-09-21 12:20:38 +0200 | [diff] [blame] | 1697 | use of generic tracepoints. |
| 1698 | |
| 1699 | Most modern CPUs support performance events via performance |
| 1700 | counter registers. These registers count the number of certain |
Thomas Gleixner | 0793a61 | 2008-12-04 20:12:29 +0100 | [diff] [blame] | 1701 | types of hw events: such as instructions executed, cachemisses |
| 1702 | suffered, or branches mis-predicted - without slowing down the |
| 1703 | kernel or applications. These registers can also trigger interrupts |
| 1704 | when a threshold number of events have passed - and can thus be |
| 1705 | used to profile the code that runs on that CPU. |
| 1706 | |
Ingo Molnar | 57c0c15 | 2009-09-21 12:20:38 +0200 | [diff] [blame] | 1707 | The Linux Performance Event subsystem provides an abstraction of |
Thadeu Lima de Souza Cascardo | dd77038 | 2009-10-30 19:32:25 -0200 | [diff] [blame] | 1708 | these software and hardware event capabilities, available via a |
Ingo Molnar | 57c0c15 | 2009-09-21 12:20:38 +0200 | [diff] [blame] | 1709 | system call and used by the "perf" utility in tools/perf/. It |
Thomas Gleixner | 0793a61 | 2008-12-04 20:12:29 +0100 | [diff] [blame] | 1710 | provides per task and per CPU counters, and it provides event |
| 1711 | capabilities on top of those. |
| 1712 | |
| 1713 | Say Y if unsure. |
| 1714 | |
Peter Zijlstra | 906010b | 2009-09-21 16:08:49 +0200 | [diff] [blame] | 1715 | config DEBUG_PERF_USE_VMALLOC |
| 1716 | default n |
| 1717 | bool "Debug: use vmalloc to back perf mmap() buffers" |
Michael Ellerman | cb307113 | 2015-05-04 16:26:39 +1000 | [diff] [blame] | 1718 | depends on PERF_EVENTS && DEBUG_KERNEL && !PPC |
Peter Zijlstra | 906010b | 2009-09-21 16:08:49 +0200 | [diff] [blame] | 1719 | select PERF_USE_VMALLOC |
| 1720 | help |
Krzysztof Kozlowski | e8cf4e9 | 2019-12-04 16:52:28 -0800 | [diff] [blame] | 1721 | Use vmalloc memory to back perf mmap() buffers. |
Peter Zijlstra | 906010b | 2009-09-21 16:08:49 +0200 | [diff] [blame] | 1722 | |
Krzysztof Kozlowski | e8cf4e9 | 2019-12-04 16:52:28 -0800 | [diff] [blame] | 1723 | Mostly useful for debugging the vmalloc code on platforms |
| 1724 | that don't require it. |
Peter Zijlstra | 906010b | 2009-09-21 16:08:49 +0200 | [diff] [blame] | 1725 | |
Krzysztof Kozlowski | e8cf4e9 | 2019-12-04 16:52:28 -0800 | [diff] [blame] | 1726 | Say N if unsure. |
Peter Zijlstra | 906010b | 2009-09-21 16:08:49 +0200 | [diff] [blame] | 1727 | |
Thomas Gleixner | 0793a61 | 2008-12-04 20:12:29 +0100 | [diff] [blame] | 1728 | endmenu |
| 1729 | |
Christoph Lameter | f8891e5 | 2006-06-30 01:55:45 -0700 | [diff] [blame] | 1730 | config VM_EVENT_COUNTERS |
| 1731 | default y |
David Rientjes | 6a108a1 | 2011-01-20 14:44:16 -0800 | [diff] [blame] | 1732 | bool "Enable VM event counters for /proc/vmstat" if EXPERT |
Christoph Lameter | f8891e5 | 2006-06-30 01:55:45 -0700 | [diff] [blame] | 1733 | help |
Paul Jackson | 2aea4fb | 2006-12-22 01:06:10 -0800 | [diff] [blame] | 1734 | VM event counters are needed for event counts to be shown. |
| 1735 | This option allows the disabling of the VM event counters |
David Rientjes | 6a108a1 | 2011-01-20 14:44:16 -0800 | [diff] [blame] | 1736 | on EXPERT systems. /proc/vmstat will only show page counts |
Paul Jackson | 2aea4fb | 2006-12-22 01:06:10 -0800 | [diff] [blame] | 1737 | if VM event counters are disabled. |
Christoph Lameter | f8891e5 | 2006-06-30 01:55:45 -0700 | [diff] [blame] | 1738 | |
Christoph Lameter | 41ecc55 | 2007-05-09 02:32:44 -0700 | [diff] [blame] | 1739 | config SLUB_DEBUG |
| 1740 | default y |
David Rientjes | 6a108a1 | 2011-01-20 14:44:16 -0800 | [diff] [blame] | 1741 | bool "Enable SLUB debugging support" if EXPERT |
Christoph Lameter | f6acb63 | 2008-04-29 16:16:06 -0700 | [diff] [blame] | 1742 | depends on SLUB && SYSFS |
Christoph Lameter | 41ecc55 | 2007-05-09 02:32:44 -0700 | [diff] [blame] | 1743 | help |
| 1744 | SLUB has extensive debug support features. Disabling these can |
| 1745 | result in significant savings in code size. This also disables |
| 1746 | SLUB sysfs support. /sys/slab will not exist and there will be |
| 1747 | no support for cache validation etc. |
| 1748 | |
Tejun Heo | 1663f26 | 2017-02-22 15:41:39 -0800 | [diff] [blame] | 1749 | config SLUB_MEMCG_SYSFS_ON |
| 1750 | default n |
| 1751 | bool "Enable memcg SLUB sysfs support by default" if EXPERT |
| 1752 | depends on SLUB && SYSFS && MEMCG |
| 1753 | help |
| 1754 | SLUB creates a directory under /sys/kernel/slab for each |
| 1755 | allocation cache to host info and debug files. If memory |
| 1756 | cgroup is enabled, each cache can have per memory cgroup |
| 1757 | caches. SLUB can create the same sysfs directories for these |
| 1758 | caches under /sys/kernel/slab/CACHE/cgroup but it can lead |
| 1759 | to a very high number of debug files being created. This is |
| 1760 | controlled by slub_memcg_sysfs boot parameter and this |
| 1761 | config option determines the parameter's default value. |
| 1762 | |
Randy Dunlap | b943c46 | 2009-03-10 12:55:46 -0700 | [diff] [blame] | 1763 | config COMPAT_BRK |
| 1764 | bool "Disable heap randomization" |
| 1765 | default y |
| 1766 | help |
| 1767 | Randomizing heap placement makes heap exploits harder, but it |
| 1768 | also breaks ancient binaries (including anything libc5 based). |
| 1769 | This option changes the bootup default to heap randomization |
Matt LaPlante | 692105b | 2009-01-26 11:12:25 +0100 | [diff] [blame] | 1770 | disabled, and can be overridden at runtime by setting |
Randy Dunlap | b943c46 | 2009-03-10 12:55:46 -0700 | [diff] [blame] | 1771 | /proc/sys/kernel/randomize_va_space to 2. |
| 1772 | |
| 1773 | On non-ancient distros (post-2000 ones) N is usually a safe choice. |
| 1774 | |
Christoph Lameter | 81819f0 | 2007-05-06 14:49:36 -0700 | [diff] [blame] | 1775 | choice |
| 1776 | prompt "Choose SLAB allocator" |
Christoph Lameter | a0acd82 | 2007-07-17 04:03:32 -0700 | [diff] [blame] | 1777 | default SLUB |
Christoph Lameter | 81819f0 | 2007-05-06 14:49:36 -0700 | [diff] [blame] | 1778 | help |
| 1779 | This option allows to select a slab allocator. |
| 1780 | |
| 1781 | config SLAB |
| 1782 | bool "SLAB" |
Kees Cook | 04385fc | 2016-06-23 15:20:59 -0700 | [diff] [blame] | 1783 | select HAVE_HARDENED_USERCOPY_ALLOCATOR |
Christoph Lameter | 81819f0 | 2007-05-06 14:49:36 -0700 | [diff] [blame] | 1784 | help |
| 1785 | The regular slab allocator that is established and known to work |
Christoph Lameter | 3401388 | 2007-05-09 02:32:47 -0700 | [diff] [blame] | 1786 | well in all environments. It organizes cache hot objects in |
Simon Arlott | 02f5621 | 2008-11-05 22:18:19 +0000 | [diff] [blame] | 1787 | per cpu and per node queues. |
Christoph Lameter | 81819f0 | 2007-05-06 14:49:36 -0700 | [diff] [blame] | 1788 | |
| 1789 | config SLUB |
Christoph Lameter | 81819f0 | 2007-05-06 14:49:36 -0700 | [diff] [blame] | 1790 | bool "SLUB (Unqueued Allocator)" |
Kees Cook | ed18adc | 2016-06-23 15:24:05 -0700 | [diff] [blame] | 1791 | select HAVE_HARDENED_USERCOPY_ALLOCATOR |
Christoph Lameter | 81819f0 | 2007-05-06 14:49:36 -0700 | [diff] [blame] | 1792 | help |
| 1793 | SLUB is a slab allocator that minimizes cache line usage |
| 1794 | instead of managing queues of cached objects (SLAB approach). |
| 1795 | Per cpu caching is realized using slabs of objects instead |
| 1796 | of queues of objects. SLUB can use memory efficiently |
Simon Arlott | 02f5621 | 2008-11-05 22:18:19 +0000 | [diff] [blame] | 1797 | and has enhanced diagnostics. SLUB is the default choice for |
| 1798 | a slab allocator. |
Christoph Lameter | 81819f0 | 2007-05-06 14:49:36 -0700 | [diff] [blame] | 1799 | |
| 1800 | config SLOB |
David Rientjes | 6a108a1 | 2011-01-20 14:44:16 -0800 | [diff] [blame] | 1801 | depends on EXPERT |
Christoph Lameter | 81819f0 | 2007-05-06 14:49:36 -0700 | [diff] [blame] | 1802 | bool "SLOB (Simple Allocator)" |
| 1803 | help |
Matt Mackall | 3729145 | 2008-02-04 22:29:38 -0800 | [diff] [blame] | 1804 | SLOB replaces the stock allocator with a drastically simpler |
| 1805 | allocator. SLOB is generally more space efficient but |
| 1806 | does not perform as well on large systems. |
Christoph Lameter | 81819f0 | 2007-05-06 14:49:36 -0700 | [diff] [blame] | 1807 | |
| 1808 | endchoice |
| 1809 | |
Kees Cook | 7660a6f | 2017-07-06 15:36:40 -0700 | [diff] [blame] | 1810 | config SLAB_MERGE_DEFAULT |
| 1811 | bool "Allow slab caches to be merged" |
| 1812 | default y |
| 1813 | help |
| 1814 | For reduced kernel memory fragmentation, slab caches can be |
| 1815 | merged when they share the same size and other characteristics. |
| 1816 | This carries a risk of kernel heap overflows being able to |
| 1817 | overwrite objects from merged caches (and more easily control |
| 1818 | cache layout), which makes such heap attacks easier to exploit |
| 1819 | by attackers. By keeping caches unmerged, these kinds of exploits |
| 1820 | can usually only damage objects in the same cache. To disable |
| 1821 | merging at runtime, "slab_nomerge" can be passed on the kernel |
| 1822 | command line. |
| 1823 | |
Thomas Garnier | c7ce4f60 | 2016-05-19 17:10:37 -0700 | [diff] [blame] | 1824 | config SLAB_FREELIST_RANDOM |
| 1825 | default n |
Thomas Garnier | 210e7a4 | 2016-07-26 15:21:59 -0700 | [diff] [blame] | 1826 | depends on SLAB || SLUB |
Thomas Garnier | c7ce4f60 | 2016-05-19 17:10:37 -0700 | [diff] [blame] | 1827 | bool "SLAB freelist randomization" |
| 1828 | help |
Thomas Garnier | 210e7a4 | 2016-07-26 15:21:59 -0700 | [diff] [blame] | 1829 | Randomizes the freelist order used on creating new pages. This |
Thomas Garnier | c7ce4f60 | 2016-05-19 17:10:37 -0700 | [diff] [blame] | 1830 | security feature reduces the predictability of the kernel slab |
| 1831 | allocator against heap overflows. |
| 1832 | |
Kees Cook | 2482ddec | 2017-09-06 16:19:18 -0700 | [diff] [blame] | 1833 | config SLAB_FREELIST_HARDENED |
| 1834 | bool "Harden slab freelist metadata" |
| 1835 | depends on SLUB |
| 1836 | help |
| 1837 | Many kernel heap attacks try to target slab cache metadata and |
| 1838 | other infrastructure. This options makes minor performance |
Kees Cook | 92bae78 | 2019-07-16 16:27:57 -0700 | [diff] [blame] | 1839 | sacrifices to harden the kernel slab allocator against common |
Kees Cook | 2482ddec | 2017-09-06 16:19:18 -0700 | [diff] [blame] | 1840 | freelist exploit methods. |
| 1841 | |
Dan Williams | e900a91 | 2019-05-14 15:41:28 -0700 | [diff] [blame] | 1842 | config SHUFFLE_PAGE_ALLOCATOR |
| 1843 | bool "Page allocator randomization" |
| 1844 | default SLAB_FREELIST_RANDOM && ACPI_NUMA |
| 1845 | help |
| 1846 | Randomization of the page allocator improves the average |
| 1847 | utilization of a direct-mapped memory-side-cache. See section |
| 1848 | 5.2.27 Heterogeneous Memory Attribute Table (HMAT) in the ACPI |
| 1849 | 6.2a specification for an example of how a platform advertises |
| 1850 | the presence of a memory-side-cache. There are also incidental |
| 1851 | security benefits as it reduces the predictability of page |
| 1852 | allocations to compliment SLAB_FREELIST_RANDOM, but the |
| 1853 | default granularity of shuffling on the "MAX_ORDER - 1" i.e, |
| 1854 | 10th order of pages is selected based on cache utilization |
| 1855 | benefits on x86. |
| 1856 | |
| 1857 | While the randomization improves cache utilization it may |
| 1858 | negatively impact workloads on platforms without a cache. For |
| 1859 | this reason, by default, the randomization is enabled only |
| 1860 | after runtime detection of a direct-mapped memory-side-cache. |
| 1861 | Otherwise, the randomization may be force enabled with the |
| 1862 | 'page_alloc.shuffle' kernel command line parameter. |
| 1863 | |
| 1864 | Say Y if unsure. |
| 1865 | |
Joonsoo Kim | 345c905 | 2013-06-19 14:05:52 +0900 | [diff] [blame] | 1866 | config SLUB_CPU_PARTIAL |
| 1867 | default y |
Uwe Kleine-König | b39ffbf | 2013-07-17 16:54:59 +0200 | [diff] [blame] | 1868 | depends on SLUB && SMP |
Joonsoo Kim | 345c905 | 2013-06-19 14:05:52 +0900 | [diff] [blame] | 1869 | bool "SLUB per cpu partial cache" |
| 1870 | help |
Kees Cook | 92bae78 | 2019-07-16 16:27:57 -0700 | [diff] [blame] | 1871 | Per cpu partial caches accelerate objects allocation and freeing |
Joonsoo Kim | 345c905 | 2013-06-19 14:05:52 +0900 | [diff] [blame] | 1872 | that is local to a processor at the price of more indeterminism |
| 1873 | in the latency of the free. On overflow these caches will be cleared |
| 1874 | which requires the taking of locks that may cause latency spikes. |
| 1875 | Typically one would choose no for a realtime system. |
| 1876 | |
Jie Zhang | ea63763 | 2009-12-14 18:00:02 -0800 | [diff] [blame] | 1877 | config MMAP_ALLOW_UNINITIALIZED |
| 1878 | bool "Allow mmapped anonymous memory to be uninitialized" |
David Rientjes | 6a108a1 | 2011-01-20 14:44:16 -0800 | [diff] [blame] | 1879 | depends on EXPERT && !MMU |
Jie Zhang | ea63763 | 2009-12-14 18:00:02 -0800 | [diff] [blame] | 1880 | default n |
| 1881 | help |
| 1882 | Normally, and according to the Linux spec, anonymous memory obtained |
Randy Dunlap | 3903bf9 | 2018-08-21 21:58:34 -0700 | [diff] [blame] | 1883 | from mmap() has its contents cleared before it is passed to |
Jie Zhang | ea63763 | 2009-12-14 18:00:02 -0800 | [diff] [blame] | 1884 | userspace. Enabling this config option allows you to request that |
| 1885 | mmap() skip that if it is given an MAP_UNINITIALIZED flag, thus |
| 1886 | providing a huge performance boost. If this option is not enabled, |
| 1887 | then the flag will be ignored. |
| 1888 | |
| 1889 | This is taken advantage of by uClibc's malloc(), and also by |
| 1890 | ELF-FDPIC binfmt's brk and stack allocator. |
| 1891 | |
| 1892 | Because of the obvious security issues, this option should only be |
| 1893 | enabled on embedded devices where you control what is run in |
| 1894 | userspace. Since that isn't generally a problem on no-MMU systems, |
| 1895 | it is normally safe to say Y here. |
| 1896 | |
| 1897 | See Documentation/nommu-mmap.txt for more information. |
| 1898 | |
David Howells | 091f6e2 | 2015-07-20 21:16:28 +0100 | [diff] [blame] | 1899 | config SYSTEM_DATA_VERIFICATION |
| 1900 | def_bool n |
| 1901 | select SYSTEM_TRUSTED_KEYRING |
| 1902 | select KEYS |
| 1903 | select CRYPTO |
David Howells | d43de6c | 2016-03-03 21:49:27 +0000 | [diff] [blame] | 1904 | select CRYPTO_RSA |
David Howells | 091f6e2 | 2015-07-20 21:16:28 +0100 | [diff] [blame] | 1905 | select ASYMMETRIC_KEY_TYPE |
| 1906 | select ASYMMETRIC_PUBLIC_KEY_SUBTYPE |
David Howells | 091f6e2 | 2015-07-20 21:16:28 +0100 | [diff] [blame] | 1907 | select ASN1 |
| 1908 | select OID_REGISTRY |
| 1909 | select X509_CERTIFICATE_PARSER |
| 1910 | select PKCS7_MESSAGE_PARSER |
Peter Foley | 82c04ff | 2014-04-18 15:07:11 -0700 | [diff] [blame] | 1911 | help |
David Howells | 091f6e2 | 2015-07-20 21:16:28 +0100 | [diff] [blame] | 1912 | Provide PKCS#7 message verification using the contents of the system |
| 1913 | trusted keyring to provide public keys. This then can be used for |
| 1914 | module verification, kexec image verification and firmware blob |
| 1915 | verification. |
Peter Foley | 82c04ff | 2014-04-18 15:07:11 -0700 | [diff] [blame] | 1916 | |
Mathieu Desnoyers | 125e564 | 2008-02-02 15:10:36 -0500 | [diff] [blame] | 1917 | config PROFILING |
Robert Richter | b309a29 | 2010-02-26 15:01:23 +0100 | [diff] [blame] | 1918 | bool "Profiling support" |
Mathieu Desnoyers | 125e564 | 2008-02-02 15:10:36 -0500 | [diff] [blame] | 1919 | help |
| 1920 | Say Y here to enable the extended profiling support mechanisms used |
| 1921 | by profilers such as OProfile. |
| 1922 | |
Ingo Molnar | 5f87f11 | 2008-07-23 14:15:22 +0200 | [diff] [blame] | 1923 | # |
| 1924 | # Place an empty function call at each tracepoint site. Can be |
| 1925 | # dynamically changed for a probe function. |
| 1926 | # |
Mathieu Desnoyers | 97e1c18 | 2008-07-18 12:16:16 -0400 | [diff] [blame] | 1927 | config TRACEPOINTS |
Ingo Molnar | 5f87f11 | 2008-07-23 14:15:22 +0200 | [diff] [blame] | 1928 | bool |
Mathieu Desnoyers | 97e1c18 | 2008-07-18 12:16:16 -0400 | [diff] [blame] | 1929 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1930 | endmenu # General setup |
| 1931 | |
Christoph Hellwig | 1572497 | 2018-07-31 13:39:30 +0200 | [diff] [blame] | 1932 | source "arch/Kconfig" |
| 1933 | |
Chuck Ebbert | ae81f9e | 2006-09-16 12:15:53 -0700 | [diff] [blame] | 1934 | config RT_MUTEXES |
Christoph Jaeger | 6341e62 | 2014-12-20 15:41:11 -0500 | [diff] [blame] | 1935 | bool |
Chuck Ebbert | ae81f9e | 2006-09-16 12:15:53 -0700 | [diff] [blame] | 1936 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1937 | config BASE_SMALL |
| 1938 | int |
| 1939 | default 0 if BASE_FULL |
| 1940 | default 1 if !BASE_FULL |
| 1941 | |
Thiago Jung Bauermann | c8424e7 | 2019-07-04 15:57:34 -0300 | [diff] [blame] | 1942 | config MODULE_SIG_FORMAT |
| 1943 | def_bool n |
| 1944 | select SYSTEM_DATA_VERIFICATION |
| 1945 | |
Jan Engelhardt | 66da573 | 2007-07-15 23:39:29 -0700 | [diff] [blame] | 1946 | menuconfig MODULES |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1947 | bool "Enable loadable module support" |
Yann E. MORIN | 11097a0 | 2013-08-11 16:07:50 +0200 | [diff] [blame] | 1948 | option modules |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1949 | help |
| 1950 | Kernel modules are small pieces of compiled code which can |
| 1951 | be inserted in the running kernel, rather than being |
| 1952 | permanently built into the kernel. You use the "modprobe" |
| 1953 | tool to add (and sometimes remove) them. If you say Y here, |
| 1954 | many parts of the kernel can be built as modules (by |
| 1955 | answering M instead of Y where indicated): this is most |
| 1956 | useful for infrequently used options which are not required |
| 1957 | for booting. For more information, see the man pages for |
| 1958 | modprobe, lsmod, modinfo, insmod and rmmod. |
| 1959 | |
| 1960 | If you say Y here, you will need to run "make |
| 1961 | modules_install" to put the modules under /lib/modules/ |
| 1962 | where modprobe can find them (you may need to be root to do |
| 1963 | this). |
| 1964 | |
| 1965 | If unsure, say Y. |
| 1966 | |
Robert P. J. Day | 0b0de14 | 2008-08-04 13:31:32 -0400 | [diff] [blame] | 1967 | if MODULES |
| 1968 | |
Linus Torvalds | 826e450 | 2008-05-04 17:04:16 -0700 | [diff] [blame] | 1969 | config MODULE_FORCE_LOAD |
| 1970 | bool "Forced module loading" |
Linus Torvalds | 826e450 | 2008-05-04 17:04:16 -0700 | [diff] [blame] | 1971 | default n |
| 1972 | help |
Rusty Russell | 91e37a7 | 2008-05-09 16:25:28 +1000 | [diff] [blame] | 1973 | Allow loading of modules without version information (ie. modprobe |
| 1974 | --force). Forced module loading sets the 'F' (forced) taint flag and |
| 1975 | is usually a really bad idea. |
Linus Torvalds | 826e450 | 2008-05-04 17:04:16 -0700 | [diff] [blame] | 1976 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1977 | config MODULE_UNLOAD |
| 1978 | bool "Module unloading" |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1979 | help |
| 1980 | Without this option you will not be able to unload any |
| 1981 | modules (note that some modules may not be unloadable |
Denys Vlasenko | f7f5b67 | 2008-07-22 19:24:26 -0500 | [diff] [blame] | 1982 | anyway), which makes your kernel smaller, faster |
| 1983 | and simpler. If unsure, say Y. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1984 | |
| 1985 | config MODULE_FORCE_UNLOAD |
| 1986 | bool "Forced module unloading" |
Kees Cook | 19c9239 | 2012-10-02 11:19:29 -0700 | [diff] [blame] | 1987 | depends on MODULE_UNLOAD |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1988 | help |
| 1989 | This option allows you to force a module to unload, even if the |
| 1990 | kernel believes it is unsafe: the kernel will remove the module |
| 1991 | without waiting for anyone to stop using it (using the -f option to |
| 1992 | rmmod). This is mainly for kernel developers and desperate users. |
| 1993 | If unsure, say N. |
| 1994 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1995 | config MODVERSIONS |
Sam Ravnborg | 0d54164 | 2005-12-26 23:04:02 +0100 | [diff] [blame] | 1996 | bool "Module versioning support" |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1997 | help |
| 1998 | Usually, you have to use modules compiled with your kernel. |
| 1999 | Saying Y here makes it sometimes possible to use modules |
| 2000 | compiled for different kernels, by adding enough information |
| 2001 | to the modules to (hopefully) spot any changes which would |
| 2002 | make them incompatible with the kernel you are running. If |
| 2003 | unsure, say N. |
| 2004 | |
Masahiro Yamada | 2ff2b7e | 2019-08-19 14:54:20 +0900 | [diff] [blame] | 2005 | config ASM_MODVERSIONS |
| 2006 | bool |
| 2007 | default HAVE_ASM_MODVERSIONS && MODVERSIONS |
| 2008 | help |
| 2009 | This enables module versioning for exported symbols also from |
| 2010 | assembly. This can be enabled only when the target architecture |
| 2011 | supports it. |
| 2012 | |
Ard Biesheuvel | 5606781 | 2017-02-03 09:54:05 +0000 | [diff] [blame] | 2013 | config MODULE_REL_CRCS |
| 2014 | bool |
| 2015 | depends on MODVERSIONS |
| 2016 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2017 | config MODULE_SRCVERSION_ALL |
| 2018 | bool "Source checksum for all modules" |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2019 | help |
| 2020 | Modules which contain a MODULE_VERSION get an extra "srcversion" |
| 2021 | field inserted into their modinfo section, which contains a |
| 2022 | sum of the source files which made it. This helps maintainers |
| 2023 | see exactly which source was used to build a module (since |
| 2024 | others sometimes change the module source without updating |
| 2025 | the version). With this option, such a "srcversion" field |
| 2026 | will be created for all modules. If unsure, say N. |
| 2027 | |
Rusty Russell | 106a4ee | 2012-09-26 10:09:40 +0100 | [diff] [blame] | 2028 | config MODULE_SIG |
| 2029 | bool "Module signature verification" |
Thiago Jung Bauermann | c8424e7 | 2019-07-04 15:57:34 -0300 | [diff] [blame] | 2030 | select MODULE_SIG_FORMAT |
Rusty Russell | 106a4ee | 2012-09-26 10:09:40 +0100 | [diff] [blame] | 2031 | help |
| 2032 | Check modules for valid signatures upon load: the signature |
| 2033 | is simply appended to the module. For more information see |
Nathan Chancellor | cbdc821 | 2017-09-10 02:48:29 -0700 | [diff] [blame] | 2034 | <file:Documentation/admin-guide/module-signing.rst>. |
Rusty Russell | 106a4ee | 2012-09-26 10:09:40 +0100 | [diff] [blame] | 2035 | |
David Howells | 228c37f | 2015-08-11 12:38:54 +0100 | [diff] [blame] | 2036 | Note that this option adds the OpenSSL development packages as a |
| 2037 | kernel build dependency so that the signing tool can use its crypto |
| 2038 | library. |
| 2039 | |
David Howells | 49fcf73 | 2019-08-19 17:17:40 -0700 | [diff] [blame] | 2040 | You should enable this option if you wish to use either |
| 2041 | CONFIG_SECURITY_LOCKDOWN_LSM or lockdown functionality imposed via |
| 2042 | another LSM - otherwise unsigned modules will be loadable regardless |
| 2043 | of the lockdown policy. |
| 2044 | |
David Howells | ea0b6dc | 2012-09-26 10:09:50 +0100 | [diff] [blame] | 2045 | !!!WARNING!!! If you enable this option, you MUST make sure that the |
| 2046 | module DOES NOT get stripped after being signed. This includes the |
| 2047 | debuginfo strip done by some packagers (such as rpmbuild) and |
| 2048 | inclusion into an initramfs that wants the module size reduced. |
| 2049 | |
Rusty Russell | 106a4ee | 2012-09-26 10:09:40 +0100 | [diff] [blame] | 2050 | config MODULE_SIG_FORCE |
| 2051 | bool "Require modules to be validly signed" |
| 2052 | depends on MODULE_SIG |
| 2053 | help |
| 2054 | Reject unsigned modules or signed modules for which we don't have a |
| 2055 | key. Without this, such modules will simply taint the kernel. |
David Howells | ea0b6dc | 2012-09-26 10:09:50 +0100 | [diff] [blame] | 2056 | |
Michal Marek | d9d8d7e | 2013-01-25 13:41:31 +1030 | [diff] [blame] | 2057 | config MODULE_SIG_ALL |
| 2058 | bool "Automatically sign all modules" |
| 2059 | default y |
| 2060 | depends on MODULE_SIG |
| 2061 | help |
| 2062 | Sign all modules during make modules_install. Without this option, |
| 2063 | modules must be signed manually, using the scripts/sign-file tool. |
| 2064 | |
| 2065 | comment "Do not forget to sign required modules with scripts/sign-file" |
| 2066 | depends on MODULE_SIG_FORCE && !MODULE_SIG_ALL |
| 2067 | |
David Howells | ea0b6dc | 2012-09-26 10:09:50 +0100 | [diff] [blame] | 2068 | choice |
| 2069 | prompt "Which hash algorithm should modules be signed with?" |
| 2070 | depends on MODULE_SIG |
| 2071 | help |
| 2072 | This determines which sort of hashing algorithm will be used during |
| 2073 | signature generation. This algorithm _must_ be built into the kernel |
| 2074 | directly so that signature verification can take place. It is not |
| 2075 | possible to load a signed module containing the algorithm to check |
| 2076 | the signature on that module. |
| 2077 | |
| 2078 | config MODULE_SIG_SHA1 |
| 2079 | bool "Sign modules with SHA-1" |
| 2080 | select CRYPTO_SHA1 |
| 2081 | |
| 2082 | config MODULE_SIG_SHA224 |
| 2083 | bool "Sign modules with SHA-224" |
| 2084 | select CRYPTO_SHA256 |
| 2085 | |
| 2086 | config MODULE_SIG_SHA256 |
| 2087 | bool "Sign modules with SHA-256" |
| 2088 | select CRYPTO_SHA256 |
| 2089 | |
| 2090 | config MODULE_SIG_SHA384 |
| 2091 | bool "Sign modules with SHA-384" |
| 2092 | select CRYPTO_SHA512 |
| 2093 | |
| 2094 | config MODULE_SIG_SHA512 |
| 2095 | bool "Sign modules with SHA-512" |
| 2096 | select CRYPTO_SHA512 |
| 2097 | |
| 2098 | endchoice |
| 2099 | |
Michal Marek | 2275367 | 2013-01-25 13:41:00 +1030 | [diff] [blame] | 2100 | config MODULE_SIG_HASH |
| 2101 | string |
| 2102 | depends on MODULE_SIG |
| 2103 | default "sha1" if MODULE_SIG_SHA1 |
| 2104 | default "sha224" if MODULE_SIG_SHA224 |
| 2105 | default "sha256" if MODULE_SIG_SHA256 |
| 2106 | default "sha384" if MODULE_SIG_SHA384 |
| 2107 | default "sha512" if MODULE_SIG_SHA512 |
| 2108 | |
Bertrand Jacquin | beb50df | 2014-08-27 20:31:56 +0930 | [diff] [blame] | 2109 | config MODULE_COMPRESS |
| 2110 | bool "Compress modules on installation" |
Bertrand Jacquin | beb50df | 2014-08-27 20:31:56 +0930 | [diff] [blame] | 2111 | help |
Bertrand Jacquin | beb50df | 2014-08-27 20:31:56 +0930 | [diff] [blame] | 2112 | |
Rusty Russell | b6c09b5 | 2015-06-16 12:16:22 +0930 | [diff] [blame] | 2113 | Compresses kernel modules when 'make modules_install' is run; gzip or |
| 2114 | xz depending on "Compression algorithm" below. |
Bertrand Jacquin | beb50df | 2014-08-27 20:31:56 +0930 | [diff] [blame] | 2115 | |
Rusty Russell | b6c09b5 | 2015-06-16 12:16:22 +0930 | [diff] [blame] | 2116 | module-init-tools MAY support gzip, and kmod MAY support gzip and xz. |
Bertrand Jacquin | beb50df | 2014-08-27 20:31:56 +0930 | [diff] [blame] | 2117 | |
Rusty Russell | b6c09b5 | 2015-06-16 12:16:22 +0930 | [diff] [blame] | 2118 | Out-of-tree kernel modules installed using Kbuild will also be |
| 2119 | compressed upon installation. |
Bertrand Jacquin | beb50df | 2014-08-27 20:31:56 +0930 | [diff] [blame] | 2120 | |
Rusty Russell | b6c09b5 | 2015-06-16 12:16:22 +0930 | [diff] [blame] | 2121 | Note: for modules inside an initrd or initramfs, it's more efficient |
| 2122 | to compress the whole initrd or initramfs instead. |
Bertrand Jacquin | beb50df | 2014-08-27 20:31:56 +0930 | [diff] [blame] | 2123 | |
Rusty Russell | b6c09b5 | 2015-06-16 12:16:22 +0930 | [diff] [blame] | 2124 | Note: This is fully compatible with signed modules. |
| 2125 | |
| 2126 | If in doubt, say N. |
Bertrand Jacquin | beb50df | 2014-08-27 20:31:56 +0930 | [diff] [blame] | 2127 | |
| 2128 | choice |
| 2129 | prompt "Compression algorithm" |
| 2130 | depends on MODULE_COMPRESS |
| 2131 | default MODULE_COMPRESS_GZIP |
| 2132 | help |
| 2133 | This determines which sort of compression will be used during |
| 2134 | 'make modules_install'. |
| 2135 | |
| 2136 | GZIP (default) and XZ are supported. |
| 2137 | |
| 2138 | config MODULE_COMPRESS_GZIP |
| 2139 | bool "GZIP" |
| 2140 | |
| 2141 | config MODULE_COMPRESS_XZ |
| 2142 | bool "XZ" |
| 2143 | |
| 2144 | endchoice |
| 2145 | |
Matthias Maennich | 3d52ec5 | 2019-09-06 11:32:29 +0100 | [diff] [blame] | 2146 | config MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS |
| 2147 | bool "Allow loading of modules with missing namespace imports" |
| 2148 | help |
| 2149 | Symbols exported with EXPORT_SYMBOL_NS*() are considered exported in |
| 2150 | a namespace. A module that makes use of a symbol exported with such a |
| 2151 | namespace is required to import the namespace via MODULE_IMPORT_NS(). |
| 2152 | There is no technical reason to enforce correct namespace imports, |
| 2153 | but it creates consistency between symbols defining namespaces and |
| 2154 | users importing namespaces they make use of. This option relaxes this |
| 2155 | requirement and lifts the enforcement when loading a module. |
| 2156 | |
| 2157 | If unsure, say N. |
| 2158 | |
Masahiro Yamada | efd9763 | 2019-09-09 20:04:08 +0900 | [diff] [blame] | 2159 | config UNUSED_SYMBOLS |
| 2160 | bool "Enable unused/obsolete exported symbols" |
| 2161 | default y if X86 |
| 2162 | help |
| 2163 | Unused but exported symbols make the kernel needlessly bigger. For |
| 2164 | that reason most of these unused exports will soon be removed. This |
| 2165 | option is provided temporarily to provide a transition period in case |
| 2166 | some external kernel module needs one of these symbols anyway. If you |
| 2167 | encounter such a case in your module, consider if you are actually |
| 2168 | using the right API. (rationale: since nobody in the kernel is using |
| 2169 | this in a module, there is a pretty good chance it's actually the |
| 2170 | wrong interface to use). If you really need the symbol, please send a |
| 2171 | mail to the linux kernel mailing list mentioning the symbol and why |
| 2172 | you really need it, and what the merge plan to the mainline kernel for |
| 2173 | your module is. |
| 2174 | |
Nicolas Pitre | dbacb0e | 2016-01-26 21:51:05 -0500 | [diff] [blame] | 2175 | config TRIM_UNUSED_KSYMS |
| 2176 | bool "Trim unused exported kernel symbols" |
Masahiro Yamada | d189c2a | 2019-09-09 20:04:07 +0900 | [diff] [blame] | 2177 | depends on !UNUSED_SYMBOLS |
Nicolas Pitre | dbacb0e | 2016-01-26 21:51:05 -0500 | [diff] [blame] | 2178 | help |
| 2179 | The kernel and some modules make many symbols available for |
| 2180 | other modules to use via EXPORT_SYMBOL() and variants. Depending |
| 2181 | on the set of modules being selected in your kernel configuration, |
| 2182 | many of those exported symbols might never be used. |
| 2183 | |
| 2184 | This option allows for unused exported symbols to be dropped from |
| 2185 | the build. In turn, this provides the compiler more opportunities |
| 2186 | (especially when using LTO) for optimizing the code and reducing |
| 2187 | binary size. This might have some security advantages as well. |
| 2188 | |
Valdis Kletnieks | f1cb637 | 2016-08-02 14:07:27 -0700 | [diff] [blame] | 2189 | If unsure, or if you need to build out-of-tree modules, say N. |
Nicolas Pitre | dbacb0e | 2016-01-26 21:51:05 -0500 | [diff] [blame] | 2190 | |
Robert P. J. Day | 0b0de14 | 2008-08-04 13:31:32 -0400 | [diff] [blame] | 2191 | endif # MODULES |
| 2192 | |
Peter Zijlstra | 6c9692e2 | 2015-05-27 11:09:37 +0930 | [diff] [blame] | 2193 | config MODULES_TREE_LOOKUP |
| 2194 | def_bool y |
| 2195 | depends on PERF_EVENTS || TRACING |
| 2196 | |
Rusty Russell | 98a79d6 | 2008-12-13 21:19:41 +1030 | [diff] [blame] | 2197 | config INIT_ALL_POSSIBLE |
| 2198 | bool |
| 2199 | help |
Rusty Russell | 5f054e3 | 2012-03-29 15:38:31 +1030 | [diff] [blame] | 2200 | Back when each arch used to define their own cpu_online_mask and |
| 2201 | cpu_possible_mask, some of them chose to initialize cpu_possible_mask |
Rusty Russell | 98a79d6 | 2008-12-13 21:19:41 +1030 | [diff] [blame] | 2202 | with all 1s, and others with all 0s. When they were centralised, |
| 2203 | it was better to provide this option than to break all the archs |
Matt LaPlante | 692105b | 2009-01-26 11:12:25 +0100 | [diff] [blame] | 2204 | and have several arch maintainers pursuing me down dark alleys. |
Rusty Russell | 98a79d6 | 2008-12-13 21:19:41 +1030 | [diff] [blame] | 2205 | |
Jens Axboe | 3a65dfe | 2005-11-04 08:43:35 +0100 | [diff] [blame] | 2206 | source "block/Kconfig" |
Avi Kivity | e98c320 | 2007-10-16 23:27:31 -0700 | [diff] [blame] | 2207 | |
| 2208 | config PREEMPT_NOTIFIERS |
| 2209 | bool |
Paul E. McKenney | e260be6 | 2008-01-25 21:08:24 +0100 | [diff] [blame] | 2210 | |
Steffen Klassert | 16295be | 2010-01-06 19:47:10 +1100 | [diff] [blame] | 2211 | config PADATA |
| 2212 | depends on SMP |
| 2213 | bool |
| 2214 | |
David Howells | 4520c6a | 2012-09-21 23:31:13 +0100 | [diff] [blame] | 2215 | config ASN1 |
| 2216 | tristate |
| 2217 | help |
| 2218 | Build a simple ASN.1 grammar compiler that produces a bytecode output |
| 2219 | that can be interpreted by the ASN.1 stream decoder and used to |
| 2220 | inform it as to what tags are to be expected in a stream and what |
| 2221 | functions to call on what tags. |
| 2222 | |
Thomas Gleixner | 6beb000 | 2009-11-09 15:21:34 +0000 | [diff] [blame] | 2223 | source "kernel/Kconfig.locks" |
Mathieu Desnoyers | e61938a | 2018-01-29 15:20:15 -0500 | [diff] [blame] | 2224 | |
| 2225 | config ARCH_HAS_SYNC_CORE_BEFORE_USERMODE |
| 2226 | bool |
Dominik Brodowski | 1bd21c6 | 2018-04-05 11:53:01 +0200 | [diff] [blame] | 2227 | |
| 2228 | # It may be useful for an architecture to override the definitions of the |
Dominik Brodowski | 7303e30 | 2018-04-05 11:53:03 +0200 | [diff] [blame] | 2229 | # SYSCALL_DEFINE() and __SYSCALL_DEFINEx() macros in <linux/syscalls.h> |
| 2230 | # and the COMPAT_ variants in <linux/compat.h>, in particular to use a |
| 2231 | # different calling convention for syscalls. They can also override the |
| 2232 | # macros for not-implemented syscalls in kernel/sys_ni.c and |
| 2233 | # kernel/time/posix-stubs.c. All these overrides need to be available in |
| 2234 | # <asm/syscall_wrapper.h>. |
Dominik Brodowski | 1bd21c6 | 2018-04-05 11:53:01 +0200 | [diff] [blame] | 2235 | config ARCH_HAS_SYSCALL_WRAPPER |
| 2236 | def_bool n |