blob: f4b210ab06129120bdddd0e937960c4c507db30d [file] [log] [blame]
Greg Kroah-Hartmanb2441312017-11-01 15:07:57 +01001# SPDX-License-Identifier: GPL-2.0
Mathieu Desnoyersfb32e032008-02-02 15:10:33 -05002#
3# General architecture dependent options
4#
Mathieu Desnoyers125e5642008-02-02 15:10:36 -05005
Christoph Hellwig15724972018-07-31 13:39:30 +02006#
7# Note: arch/$(SRCARCH)/Kconfig needs to be included first so that it can
8# override the default values in this file.
9#
10source "arch/$(SRCARCH)/Kconfig"
11
Randy Dunlap22471e12018-07-31 13:39:33 +020012menu "General architecture-dependent options"
13
Catalin Marinasda32b582022-04-23 11:07:49 +010014config ARCH_HAS_SUBPAGE_FAULTS
15 bool
16 help
17 Select if the architecture can check permissions at sub-page
18 granularity (e.g. arm64 MTE). The probe_user_*() functions
19 must be implemented.
20
Thomas Gleixner05736e42018-05-29 17:48:27 +020021config HOTPLUG_SMT
22 bool
23
Michael Ellerman38253462023-07-05 16:51:39 +020024config SMT_NUM_THREADS_DYNAMIC
25 bool
26
Thomas Gleixner6f062122023-05-12 23:07:27 +020027# Selected by HOTPLUG_CORE_SYNC_DEAD or HOTPLUG_CORE_SYNC_FULL
28config HOTPLUG_CORE_SYNC
29 bool
30
31# Basic CPU dead synchronization selected by architecture
32config HOTPLUG_CORE_SYNC_DEAD
33 bool
34 select HOTPLUG_CORE_SYNC
35
36# Full CPU synchronization with alive state selected by architecture
37config HOTPLUG_CORE_SYNC_FULL
38 bool
39 select HOTPLUG_CORE_SYNC_DEAD if HOTPLUG_CPU
40 select HOTPLUG_CORE_SYNC
41
Thomas Gleixnera631be922023-05-12 23:07:45 +020042config HOTPLUG_SPLIT_STARTUP
43 bool
44 select HOTPLUG_CORE_SYNC_FULL
45
Thomas Gleixner18415f32023-05-12 23:07:50 +020046config HOTPLUG_PARALLEL
47 bool
48 select HOTPLUG_SPLIT_STARTUP
49
Thomas Gleixner142781e2020-07-22 23:59:56 +020050config GENERIC_ENTRY
Juerg Haefliger9f79ffc2023-02-01 17:24:35 +010051 bool
Thomas Gleixner142781e2020-07-22 23:59:56 +020052
Mathieu Desnoyers125e5642008-02-02 15:10:36 -050053config KPROBES
54 bool "Kprobes"
Masami Hiramatsu05ed1602010-09-13 19:25:41 +090055 depends on MODULES
Mathieu Desnoyers125e5642008-02-02 15:10:36 -050056 depends on HAVE_KPROBES
Masami Hiramatsu05ed1602010-09-13 19:25:41 +090057 select KALLSYMS
Paul E. McKenney835f14e2022-03-17 11:05:09 -070058 select TASKS_RCU if PREEMPTION
Mathieu Desnoyers125e5642008-02-02 15:10:36 -050059 help
60 Kprobes allows you to trap at almost any kernel address and
61 execute a callback function. register_kprobe() establishes
62 a probepoint and specifies the callback. Kprobes is useful
63 for kernel debugging, non-intrusive instrumentation and testing.
64 If in doubt, say "N".
65
Steven Rostedt45f81b12010-10-29 12:33:43 -040066config JUMP_LABEL
Krzysztof Kozlowski24b54fe2019-12-04 16:50:26 -080067 bool "Optimize very unlikely/likely branches"
68 depends on HAVE_ARCH_JUMP_LABEL
Josh Poimboeuf4ab76742022-04-18 09:50:39 -070069 select OBJTOOL if HAVE_JUMP_LABEL_HACK
Krzysztof Kozlowski24b54fe2019-12-04 16:50:26 -080070 help
Juerg Haefliger9f79ffc2023-02-01 17:24:35 +010071 This option enables a transparent branch optimization that
72 makes certain almost-always-true or almost-always-false branch
73 conditions even cheaper to execute within the kernel.
Steven Rostedt45f81b12010-10-29 12:33:43 -040074
Juerg Haefliger9f79ffc2023-02-01 17:24:35 +010075 Certain performance-sensitive kernel code, such as trace points,
76 scheduler functionality, networking code and KVM have such
77 branches and include support for this optimization technique.
Ingo Molnarc5905af2012-02-24 08:31:31 +010078
Juerg Haefliger9f79ffc2023-02-01 17:24:35 +010079 If it is detected that the compiler has support for "asm goto",
80 the kernel will compile such branches with just a nop
81 instruction. When the condition flag is toggled to true, the
82 nop will be converted to a jump instruction to execute the
83 conditional block of instructions.
Ingo Molnarc5905af2012-02-24 08:31:31 +010084
Juerg Haefliger9f79ffc2023-02-01 17:24:35 +010085 This technique lowers overhead and stress on the branch prediction
86 of the processor and generally makes the kernel faster. The update
87 of the condition is slower, but those are always very rare.
Ingo Molnarc5905af2012-02-24 08:31:31 +010088
Juerg Haefliger9f79ffc2023-02-01 17:24:35 +010089 ( On 32-bit x86, the necessary options added to the compiler
90 flags may increase the size of the kernel slightly. )
Steven Rostedt45f81b12010-10-29 12:33:43 -040091
Peter Zijlstra1987c942015-07-27 18:32:09 +020092config STATIC_KEYS_SELFTEST
93 bool "Static key selftest"
94 depends on JUMP_LABEL
95 help
96 Boot time self-test of the branch patching code.
97
Peter Zijlstraf03c4122020-08-18 15:57:46 +020098config STATIC_CALL_SELFTEST
99 bool "Static call selftest"
100 depends on HAVE_STATIC_CALL
101 help
102 Boot time self-test of the call patching code.
103
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500104config OPTPROBES
Masami Hiramatsu5cc718b2010-03-15 13:00:54 -0400105 def_bool y
106 depends on KPROBES && HAVE_OPTPROBES
Thomas Gleixner01b1d882019-07-26 23:19:38 +0200107 select TASKS_RCU if PREEMPTION
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500108
Masami Hiramatsue7dbfe32012-09-28 17:15:20 +0900109config KPROBES_ON_FTRACE
110 def_bool y
111 depends on KPROBES && HAVE_KPROBES_ON_FTRACE
112 depends on DYNAMIC_FTRACE_WITH_REGS
113 help
Juerg Haefliger9f79ffc2023-02-01 17:24:35 +0100114 If function tracer is enabled and the arch supports full
115 passing of pt_regs to function tracing, then kprobes can
116 optimize on top of function tracing.
Masami Hiramatsue7dbfe32012-09-28 17:15:20 +0900117
Srikar Dronamraju2b144492012-02-09 14:56:42 +0530118config UPROBES
David A. Long09294e32014-03-07 10:32:22 -0500119 def_bool n
Allen Paise8f4aa62016-10-13 10:06:13 +0530120 depends on ARCH_SUPPORTS_UPROBES
Srikar Dronamraju2b144492012-02-09 14:56:42 +0530121 help
Ingo Molnar7b2d81d2012-02-17 09:27:41 +0100122 Uprobes is the user-space counterpart to kprobes: they
123 enable instrumentation applications (such as 'perf probe')
124 to establish unintrusive probes in user-space binaries and
125 libraries, by executing handler functions when the probes
126 are hit by user-space applications.
127
128 ( These probes come in the form of single-byte breakpoints,
129 managed by the kernel and kept transparent to the probed
130 application. )
Srikar Dronamraju2b144492012-02-09 14:56:42 +0530131
Steven Rostedt (VMware)adab66b2020-12-14 12:33:51 -0500132config HAVE_64BIT_ALIGNED_ACCESS
133 def_bool 64BIT && !HAVE_EFFICIENT_UNALIGNED_ACCESS
134 help
135 Some architectures require 64 bit accesses to be 64 bit
136 aligned, which also requires structs containing 64 bit values
137 to be 64 bit aligned too. This includes some 32 bit
138 architectures which can do 64 bit accesses, as well as 64 bit
139 architectures without unaligned access.
140
141 This symbol should be selected by an architecture if 64 bit
142 accesses are required to be 64 bit aligned in this way even
143 though it is not a 64 bit architecture.
144
Lukas Bulwahnba1a2972021-01-19 10:53:26 +0100145 See Documentation/core-api/unaligned-memory-access.rst for
146 more information on the topic of unaligned memory accesses.
Steven Rostedt (VMware)adab66b2020-12-14 12:33:51 -0500147
Johannes Berg58340a02008-07-25 01:45:33 -0700148config HAVE_EFFICIENT_UNALIGNED_ACCESS
Jan Beulich9ba16082008-10-15 22:01:38 -0700149 bool
Johannes Berg58340a02008-07-25 01:45:33 -0700150 help
151 Some architectures are unable to perform unaligned accesses
152 without the use of get_unaligned/put_unaligned. Others are
153 unable to perform such accesses efficiently (e.g. trap on
154 unaligned access and require fixing it up in the exception
155 handler.)
156
157 This symbol should be selected by an architecture if it can
158 perform unaligned accesses efficiently to allow different
159 code paths to be selected for these cases. Some network
160 drivers, for example, could opt to not fix up alignment
161 problems with received packets if doing so would not help
162 much.
163
Mauro Carvalho Chehabc9b54d62020-06-23 15:31:38 +0200164 See Documentation/core-api/unaligned-memory-access.rst for more
Johannes Berg58340a02008-07-25 01:45:33 -0700165 information on the topic of unaligned memory accesses.
166
David Woodhousecf66bb92012-12-03 16:25:40 +0000167config ARCH_USE_BUILTIN_BSWAP
Krzysztof Kozlowski24b54fe2019-12-04 16:50:26 -0800168 bool
169 help
Juerg Haefliger9f79ffc2023-02-01 17:24:35 +0100170 Modern versions of GCC (since 4.4) have builtin functions
171 for handling byte-swapping. Using these, instead of the old
172 inline assembler that the architecture code provides in the
173 __arch_bswapXX() macros, allows the compiler to see what's
174 happening and offers more opportunity for optimisation. In
175 particular, the compiler will be able to combine the byteswap
176 with a nearby load or store and use load-and-swap or
177 store-and-swap instructions if the architecture has them. It
178 should almost *never* result in code which is worse than the
179 hand-coded assembler in <asm/swab.h>. But just in case it
180 does, the use of the builtins is optional.
David Woodhousecf66bb92012-12-03 16:25:40 +0000181
Juerg Haefliger9f79ffc2023-02-01 17:24:35 +0100182 Any architecture with load-and-swap or store-and-swap
183 instructions should set this. And it shouldn't hurt to set it
184 on architectures that don't have such instructions.
David Woodhousecf66bb92012-12-03 16:25:40 +0000185
Ananth N Mavinakayanahalli9edddaa2008-03-04 14:28:37 -0800186config KRETPROBES
187 def_bool y
Masami Hiramatsu73f9b912022-03-26 11:27:05 +0900188 depends on KPROBES && (HAVE_KRETPROBES || HAVE_RETHOOK)
189
190config KRETPROBE_ON_RETHOOK
191 def_bool y
192 depends on HAVE_RETHOOK
193 depends on KRETPROBES
194 select RETHOOK
Ananth N Mavinakayanahalli9edddaa2008-03-04 14:28:37 -0800195
Avi Kivity7c68af62009-09-19 09:40:22 +0300196config USER_RETURN_NOTIFIER
197 bool
198 depends on HAVE_USER_RETURN_NOTIFIER
199 help
200 Provide a kernel-internal notification when a cpu is about to
201 switch to user mode.
202
Rik van Riel28b2ee22008-07-23 21:27:05 -0700203config HAVE_IOREMAP_PROT
Jan Beulich9ba16082008-10-15 22:01:38 -0700204 bool
Rik van Riel28b2ee22008-07-23 21:27:05 -0700205
Mathieu Desnoyers125e5642008-02-02 15:10:36 -0500206config HAVE_KPROBES
Jan Beulich9ba16082008-10-15 22:01:38 -0700207 bool
Ananth N Mavinakayanahalli9edddaa2008-03-04 14:28:37 -0800208
209config HAVE_KRETPROBES
Jan Beulich9ba16082008-10-15 22:01:38 -0700210 bool
Arthur Kepner74bc7ce2008-04-29 01:00:30 -0700211
Masami Hiramatsuafd66252010-02-25 08:34:07 -0500212config HAVE_OPTPROBES
213 bool
Cong Wangd314d742012-03-23 15:01:51 -0700214
Masami Hiramatsue7dbfe32012-09-28 17:15:20 +0900215config HAVE_KPROBES_ON_FTRACE
216 bool
217
Masami Hiramatsu1f6d3a82021-10-25 20:41:52 +0900218config ARCH_CORRECT_STACKTRACE_ON_KRETPROBE
219 bool
220 help
221 Since kretprobes modifies return address on the stack, the
222 stacktrace may see the kretprobe trampoline address instead
223 of correct one. If the architecture stacktrace code and
224 unwinder can adjust such entries, select this configuration.
225
Masami Hiramatsu540adea2018-01-13 02:55:03 +0900226config HAVE_FUNCTION_ERROR_INJECTION
Josef Bacik9802d862017-12-11 11:36:48 -0500227 bool
228
Petr Mladek42a0bb32016-05-20 17:00:33 -0700229config HAVE_NMI
230 bool
231
Christophe Leroya257cac2022-02-15 13:41:02 +0100232config HAVE_FUNCTION_DESCRIPTORS
233 bool
234
Masahiro Yamada4aae6832021-07-31 14:22:32 +0900235config TRACE_IRQFLAGS_SUPPORT
236 bool
237
Mark Rutland4510bff2022-05-11 14:17:32 +0100238config TRACE_IRQFLAGS_NMI_SUPPORT
239 bool
240
Roland McGrath1f5a4ad2008-07-25 19:45:57 -0700241#
242# An arch should select this if it provides all these things:
243#
244# task_pt_regs() in asm/processor.h or asm/ptrace.h
245# arch_has_single_step() if there is hardware single-step support
246# arch_has_block_step() if there is hardware block-step support
Roland McGrath1f5a4ad2008-07-25 19:45:57 -0700247# asm/syscall.h supplying asm-generic/syscall.h interface
248# linux/regset.h user_regset interfaces
249# CORE_DUMP_USE_REGSET #define'd in linux/elf.h
Eric W. Biederman153474b2022-01-27 11:46:37 -0600250# TIF_SYSCALL_TRACE calls ptrace_report_syscall_{entry,exit}
Eric W. Biederman03248ad2022-02-09 12:20:45 -0600251# TIF_NOTIFY_RESUME calls resume_user_mode_work()
Roland McGrath1f5a4ad2008-07-25 19:45:57 -0700252#
253config HAVE_ARCH_TRACEHOOK
Jan Beulich9ba16082008-10-15 22:01:38 -0700254 bool
Roland McGrath1f5a4ad2008-07-25 19:45:57 -0700255
Marek Szyprowskic64be2b2011-12-29 13:09:51 +0100256config HAVE_DMA_CONTIGUOUS
257 bool
258
Thomas Gleixner29d5e042012-04-20 13:05:45 +0000259config GENERIC_SMP_IDLE_THREAD
Krzysztof Kozlowski24b54fe2019-12-04 16:50:26 -0800260 bool
Thomas Gleixner29d5e042012-04-20 13:05:45 +0000261
Kevin Hilman485cf5d2013-04-24 17:19:13 -0700262config GENERIC_IDLE_POLL_SETUP
Krzysztof Kozlowski24b54fe2019-12-04 16:50:26 -0800263 bool
Kevin Hilman485cf5d2013-04-24 17:19:13 -0700264
Daniel Micay6974f0c2017-07-12 14:36:10 -0700265config ARCH_HAS_FORTIFY_SOURCE
266 bool
267 help
268 An architecture should select this when it can successfully
269 build and run with CONFIG_FORTIFY_SOURCE.
270
Christoph Hellwigd8ae8a32019-05-13 17:18:30 -0700271#
272# Select if the arch provides a historic keepinit alias for the retain_initrd
273# command line option
274#
275config ARCH_HAS_KEEPINITRD
276 bool
277
Daniel Borkmannd2852a22017-02-21 16:09:33 +0100278# Select if arch has all set_memory_ro/rw/x/nx() functions in asm/cacheflush.h
279config ARCH_HAS_SET_MEMORY
280 bool
281
Rick Edgecombed253ca02019-04-25 17:11:34 -0700282# Select if arch has all set_direct_map_invalid/default() functions
283config ARCH_HAS_SET_DIRECT_MAP
284 bool
285
Christoph Hellwigc30700d2019-06-03 08:43:51 +0200286#
Christoph Hellwigfa7e2242020-02-21 15:55:43 -0800287# Select if the architecture provides the arch_dma_set_uncached symbol to
Colin Ian Kinga86ecfa2020-12-14 19:03:44 -0800288# either provide an uncached segment alias for a DMA allocation, or
Christoph Hellwigfa7e2242020-02-21 15:55:43 -0800289# to remap the page tables in place.
Christoph Hellwigc30700d2019-06-03 08:43:51 +0200290#
Christoph Hellwigfa7e2242020-02-21 15:55:43 -0800291config ARCH_HAS_DMA_SET_UNCACHED
Christoph Hellwigc30700d2019-06-03 08:43:51 +0200292 bool
293
Christoph Hellwig999a5d12020-02-21 12:35:05 -0800294#
295# Select if the architectures provides the arch_dma_clear_uncached symbol
296# to undo an in-place page table remap for uncached access.
297#
298config ARCH_HAS_DMA_CLEAR_UNCACHED
Thomas Gleixnerf5e10282012-05-05 15:05:48 +0000299 bool
300
Thomas Gleixner7725aca2023-06-14 01:39:22 +0200301config ARCH_HAS_CPU_FINALIZE_INIT
302 bool
303
Thomas Gleixnera6359d12012-05-03 09:03:02 +0000304# Select if arch init_task must go in the __init_task_data section
305config ARCH_TASK_STRUCT_ON_STACK
Krzysztof Kozlowski24b54fe2019-12-04 16:50:26 -0800306 bool
Thomas Gleixnera4a2eb42012-05-03 09:02:48 +0000307
Thomas Gleixnerf5e10282012-05-05 15:05:48 +0000308# Select if arch has its private alloc_task_struct() function
309config ARCH_TASK_STRUCT_ALLOCATOR
310 bool
311
Kees Cook59054292017-08-16 13:00:58 -0700312config HAVE_ARCH_THREAD_STRUCT_WHITELIST
313 bool
314 depends on !ARCH_TASK_STRUCT_ALLOCATOR
315 help
316 An architecture should select this to provide hardened usercopy
317 knowledge about what region of the thread_struct should be
318 whitelisted for copying to userspace. Normally this is only the
319 FPU registers. Specifically, arch_thread_struct_whitelist()
320 should be implemented. Without this, the entire thread_struct
321 field in task_struct will be left whitelisted.
322
Linus Torvaldsb235bee2016-06-24 15:09:37 -0700323# Select if arch has its private alloc_thread_stack() function
324config ARCH_THREAD_STACK_ALLOCATOR
Thomas Gleixnerf5e10282012-05-05 15:05:48 +0000325 bool
326
Ingo Molnar5aaeb5c2015-07-17 12:28:12 +0200327# Select if arch wants to size task_struct dynamically via arch_task_struct_size:
328config ARCH_WANTS_DYNAMIC_TASK_STRUCT
329 bool
330
Nick Desaulniers51c2ee62021-06-21 16:18:22 -0700331config ARCH_WANTS_NO_INSTR
332 bool
333 help
334 An architecture should select this if the noinstr macro is being used on
335 functions to denote that the toolchain should avoid instrumenting such
336 functions and is required for correctness.
337
Yury Norov942fa982018-05-16 11:18:49 +0300338config ARCH_32BIT_OFF_T
339 bool
340 depends on !64BIT
341 help
342 All new 32-bit architectures should have 64-bit off_t type on
343 userspace side which corresponds to the loff_t kernel type. This
344 is the requirement for modern ABIs. Some existing architectures
345 still support 32-bit off_t. This option is enabled for all such
346 architectures explicitly.
347
Heiko Carstens96c0a6a2021-02-10 21:51:02 +0100348# Selected by 64 bit architectures which have a 32 bit f_tinode in struct ustat
349config ARCH_32BIT_USTAT_F_TINODE
350 bool
351
Masahiro Yamada2ff2b7e2019-08-19 14:54:20 +0900352config HAVE_ASM_MODVERSIONS
353 bool
354 help
Colin Ian Kinga86ecfa2020-12-14 19:03:44 -0800355 This symbol should be selected by an architecture if it provides
Masahiro Yamada2ff2b7e2019-08-19 14:54:20 +0900356 <asm/asm-prototypes.h> to support the module versioning for symbols
357 exported from assembly code.
358
Heiko Carstensf850c30c2010-02-10 17:25:17 +0100359config HAVE_REGS_AND_STACK_ACCESS_API
360 bool
Heiko Carstense01292b2010-02-18 14:25:21 +0100361 help
Colin Ian Kinga86ecfa2020-12-14 19:03:44 -0800362 This symbol should be selected by an architecture if it supports
Heiko Carstense01292b2010-02-18 14:25:21 +0100363 the API needed to access registers and stack entries from pt_regs,
364 declared in asm/ptrace.h
365 For example the kprobes-based event tracer needs this API.
Heiko Carstensf850c30c2010-02-10 17:25:17 +0100366
Mathieu Desnoyersd7822b12018-06-02 08:43:54 -0400367config HAVE_RSEQ
368 bool
369 depends on HAVE_REGS_AND_STACK_ACCESS_API
370 help
371 This symbol should be selected by an architecture if it
372 supports an implementation of restartable sequences.
373
Miguel Ojeda2f7ab122021-07-03 16:42:57 +0200374config HAVE_RUST
375 bool
376 help
377 This symbol should be selected by an architecture if it
378 supports Rust.
379
Masami Hiramatsu3c88ee194c2018-04-25 21:20:57 +0900380config HAVE_FUNCTION_ARG_ACCESS_API
381 bool
382 help
Colin Ian Kinga86ecfa2020-12-14 19:03:44 -0800383 This symbol should be selected by an architecture if it supports
Masami Hiramatsu3c88ee194c2018-04-25 21:20:57 +0900384 the API needed to access function arguments from pt_regs,
385 declared in asm/ptrace.h
386
K.Prasad62a038d2009-06-01 23:43:33 +0530387config HAVE_HW_BREAKPOINT
388 bool
Frederic Weisbecker99e8c5a2009-12-17 01:33:54 +0100389 depends on PERF_EVENTS
K.Prasad62a038d2009-06-01 23:43:33 +0530390
Frederic Weisbecker01027522010-04-11 18:55:56 +0200391config HAVE_MIXED_BREAKPOINTS_REGS
392 bool
393 depends on HAVE_HW_BREAKPOINT
394 help
395 Depending on the arch implementation of hardware breakpoints,
396 some of them have separate registers for data and instruction
397 breakpoints addresses, others have mixed registers to store
398 them but define the access type in a control register.
399 Select this option if your arch implements breakpoints under the
400 latter fashion.
401
Avi Kivity7c68af62009-09-19 09:40:22 +0300402config HAVE_USER_RETURN_NOTIFIER
403 bool
Ingo Molnara1922ed2009-09-07 08:19:51 +0200404
Frederic Weisbeckerc01d4322010-05-15 22:57:48 +0200405config HAVE_PERF_EVENTS_NMI
406 bool
Frederic Weisbecker23637d42010-05-15 23:15:20 +0200407 help
408 System hardware can generate an NMI using the perf event
409 subsystem. Also has support for calculating CPU cycle events
410 to determine how many clock cycles in a given period.
Frederic Weisbeckerc01d4322010-05-15 22:57:48 +0200411
Nicholas Piggin05a4a952017-07-12 14:35:46 -0700412config HAVE_HARDLOCKUP_DETECTOR_PERF
413 bool
414 depends on HAVE_PERF_EVENTS_NMI
415 help
416 The arch chooses to use the generic perf-NMI-based hardlockup
417 detector. Must define HAVE_PERF_EVENTS_NMI.
418
Nicholas Piggin05a4a952017-07-12 14:35:46 -0700419config HAVE_HARDLOCKUP_DETECTOR_ARCH
420 bool
Nicholas Piggin05a4a952017-07-12 14:35:46 -0700421 help
Petr Mladek1356d0b2023-06-16 17:06:14 +0200422 The arch provides its own hardlockup detector implementation instead
423 of the generic ones.
424
425 It uses the same command line parameters, and sysctl interface,
426 as the generic hardlockup detectors.
Nicholas Piggin05a4a952017-07-12 14:35:46 -0700427
Jiri Olsac5e63192012-08-07 15:20:36 +0200428config HAVE_PERF_REGS
429 bool
430 help
431 Support selective register dumps for perf events. This includes
432 bit-mapping of each registers and a unique architecture id.
433
Jiri Olsac5ebced2012-08-07 15:20:40 +0200434config HAVE_PERF_USER_STACK_DUMP
435 bool
436 help
437 Support user stack dumps for perf event samples. This needs
438 access to the user stack pointer which is not unified across
439 architectures.
440
Jason Baronbf5438fc2010-09-17 11:09:00 -0400441config HAVE_ARCH_JUMP_LABEL
442 bool
443
Ard Biesheuvel50ff18a2018-09-18 23:51:37 -0700444config HAVE_ARCH_JUMP_LABEL_RELATIVE
445 bool
446
Peter Zijlstra0d6e24d2020-02-03 17:37:11 -0800447config MMU_GATHER_TABLE_FREE
448 bool
449
Peter Zijlstraff2e6d722020-02-03 17:37:02 -0800450config MMU_GATHER_RCU_TABLE_FREE
Peter Zijlstra26723912011-05-24 17:12:00 -0700451 bool
Peter Zijlstra0d6e24d2020-02-03 17:37:11 -0800452 select MMU_GATHER_TABLE_FREE
Peter Zijlstra26723912011-05-24 17:12:00 -0700453
Peter Zijlstra3af4bd02020-02-03 17:37:05 -0800454config MMU_GATHER_PAGE_SIZE
Peter Zijlstraed6a7932018-08-31 14:46:08 +0200455 bool
456
Peter Zijlstra27796d032020-02-03 17:36:59 -0800457config MMU_GATHER_NO_RANGE
458 bool
Peter Zijlstra1e9fdf22022-07-08 09:18:03 +0200459 select MMU_GATHER_MERGE_VMAS
460
461config MMU_GATHER_NO_FLUSH_CACHE
462 bool
463
464config MMU_GATHER_MERGE_VMAS
465 bool
Peter Zijlstra27796d032020-02-03 17:36:59 -0800466
Peter Zijlstra580a5862020-02-03 17:37:08 -0800467config MMU_GATHER_NO_GATHER
Martin Schwidefsky952a31c2018-09-18 14:51:50 +0200468 bool
Peter Zijlstra0d6e24d2020-02-03 17:37:11 -0800469 depends on MMU_GATHER_TABLE_FREE
Martin Schwidefsky952a31c2018-09-18 14:51:50 +0200470
Nicholas Piggind53c3df2020-09-14 14:52:16 +1000471config ARCH_WANT_IRQS_OFF_ACTIVATE_MM
472 bool
473 help
474 Temporary select until all architectures can be converted to have
475 irqs disabled over activate_mm. Architectures that do IPI based TLB
476 shootdowns should enable this.
477
Nicholas Piggin88e30092023-02-03 17:18:35 +1000478# Use normal mm refcounting for MMU_LAZY_TLB kernel thread references.
479# MMU_LAZY_TLB_REFCOUNT=n can improve the scalability of context switching
480# to/from kernel threads when the same mm is running on a lot of CPUs (a large
481# multi-threaded application), by reducing contention on the mm refcount.
482#
483# This can be disabled if the architecture ensures no CPUs are using an mm as a
484# "lazy tlb" beyond its final refcount (i.e., by the time __mmdrop frees the mm
485# or its kernel page tables). This could be arranged by arch_exit_mmap(), or
486# final exit(2) TLB flush, for example.
487#
488# To implement this, an arch *must*:
489# Ensure the _lazy_tlb variants of mmgrab/mmdrop are used when manipulating
490# the lazy tlb reference of a kthread's ->active_mm (non-arch code has been
491# converted already).
492config MMU_LAZY_TLB_REFCOUNT
493 def_bool y
Nicholas Piggin26554212023-02-03 17:18:36 +1000494 depends on !MMU_LAZY_TLB_SHOOTDOWN
495
496# This option allows MMU_LAZY_TLB_REFCOUNT=n. It ensures no CPUs are using an
497# mm as a lazy tlb beyond its last reference count, by shooting down these
498# users before the mm is deallocated. __mmdrop() first IPIs all CPUs that may
499# be using the mm as a lazy tlb, so that they may switch themselves to using
500# init_mm for their active mm. mm_cpumask(mm) is used to determine which CPUs
501# may be using mm as a lazy tlb mm.
502#
503# To implement this, an arch *must*:
504# - At the time of the final mmdrop of the mm, ensure mm_cpumask(mm) contains
505# at least all possible CPUs in which the mm is lazy.
506# - It must meet the requirements for MMU_LAZY_TLB_REFCOUNT=n (see above).
507config MMU_LAZY_TLB_SHOOTDOWN
508 bool
Nicholas Piggin88e30092023-02-03 17:18:35 +1000509
Huang Yingdf013ff2011-07-13 13:14:22 +0800510config ARCH_HAVE_NMI_SAFE_CMPXCHG
511 bool
512
Paul E. McKenney2e83b872022-09-15 14:29:07 -0700513config ARCH_HAS_NMI_SAFE_THIS_CPU_OPS
514 bool
515
Heiko Carstens43570fd2012-01-12 17:17:27 -0800516config HAVE_ALIGNED_STRUCT_PAGE
517 bool
518 help
519 This makes sure that struct pages are double word aligned and that
520 e.g. the SLUB allocator can perform double word atomic operations
521 on a struct page for better performance. However selecting this
522 might increase the size of a struct page by a word.
523
Heiko Carstens41561532012-01-12 17:17:30 -0800524config HAVE_CMPXCHG_LOCAL
525 bool
526
Heiko Carstens25654092012-01-12 17:17:33 -0800527config HAVE_CMPXCHG_DOUBLE
528 bool
529
Paul E. McKenney77e58492017-01-14 13:32:50 -0800530config ARCH_WEAK_RELEASE_ACQUIRE
531 bool
532
Will Deaconc1d7e012012-07-30 14:42:46 -0700533config ARCH_WANT_IPC_PARSE_VERSION
534 bool
535
536config ARCH_WANT_COMPAT_IPC_PARSE_VERSION
537 bool
538
Chris Metcalf48b25c42012-03-15 13:13:38 -0400539config ARCH_WANT_OLD_COMPAT_IPC
Will Deaconc1d7e012012-07-30 14:42:46 -0700540 select ARCH_WANT_COMPAT_IPC_PARSE_VERSION
Chris Metcalf48b25c42012-03-15 13:13:38 -0400541 bool
542
YiFei Zhu282a1812020-09-24 07:44:16 -0500543config HAVE_ARCH_SECCOMP
Will Drewrye2cfabdf2012-04-12 16:47:57 -0500544 bool
545 help
YiFei Zhu282a1812020-09-24 07:44:16 -0500546 An arch should select this symbol to support seccomp mode 1 (the fixed
547 syscall policy), and must provide an overrides for __NR_seccomp_sigreturn,
548 and compat syscalls if the asm-generic/seccomp.h defaults need adjustment:
549 - __NR_seccomp_read_32
550 - __NR_seccomp_write_32
551 - __NR_seccomp_exit_32
552 - __NR_seccomp_sigreturn_32
553
554config HAVE_ARCH_SECCOMP_FILTER
555 bool
556 select HAVE_ARCH_SECCOMP
557 help
Will Drewryfb0fadf2012-04-12 16:48:02 -0500558 An arch should select this symbol if it provides all of these things:
YiFei Zhu282a1812020-09-24 07:44:16 -0500559 - all the requirements for HAVE_ARCH_SECCOMP
Will Drewrybb6ea432012-04-12 16:48:01 -0500560 - syscall_get_arch()
561 - syscall_get_arguments()
562 - syscall_rollback()
563 - syscall_set_return_value()
Will Drewryfb0fadf2012-04-12 16:48:02 -0500564 - SIGSYS siginfo_t support
565 - secure_computing is called from a ptrace_event()-safe context
566 - secure_computing return value is checked and a return value of -1
567 results in the system call being skipped immediately.
Kees Cook48dc92b2014-06-25 16:08:24 -0700568 - seccomp syscall wired up
YiFei Zhu0d8315d2020-11-11 07:33:54 -0600569 - if !HAVE_SPARSE_SYSCALL_NR, have SECCOMP_ARCH_NATIVE,
570 SECCOMP_ARCH_NATIVE_NR, SECCOMP_ARCH_NATIVE_NAME defined. If
571 COMPAT is supported, have the SECCOMP_ARCH_COMPAT* defines too.
Will Drewrye2cfabdf2012-04-12 16:47:57 -0500572
YiFei Zhu282a1812020-09-24 07:44:16 -0500573config SECCOMP
574 prompt "Enable seccomp to safely execute untrusted bytecode"
575 def_bool y
576 depends on HAVE_ARCH_SECCOMP
577 help
578 This kernel feature is useful for number crunching applications
579 that may need to handle untrusted bytecode during their
580 execution. By using pipes or other transports made available
581 to the process as file descriptors supporting the read/write
582 syscalls, it's possible to isolate those applications in their
583 own address space using seccomp. Once seccomp is enabled via
584 prctl(PR_SET_SECCOMP) or the seccomp() syscall, it cannot be
585 disabled and the task is only allowed to execute a few safe
586 syscalls defined by each seccomp mode.
587
588 If unsure, say Y.
589
Will Drewrye2cfabdf2012-04-12 16:47:57 -0500590config SECCOMP_FILTER
591 def_bool y
592 depends on HAVE_ARCH_SECCOMP_FILTER && SECCOMP && NET
593 help
594 Enable tasks to build secure computing environments defined
595 in terms of Berkeley Packet Filter programs which implement
596 task-defined system call filtering polices.
597
Mauro Carvalho Chehab5fb94e92018-05-08 15:14:57 -0300598 See Documentation/userspace-api/seccomp_filter.rst for details.
Will Drewrye2cfabdf2012-04-12 16:47:57 -0500599
YiFei Zhu0d8315d2020-11-11 07:33:54 -0600600config SECCOMP_CACHE_DEBUG
601 bool "Show seccomp filter cache status in /proc/pid/seccomp_cache"
602 depends on SECCOMP_FILTER && !HAVE_SPARSE_SYSCALL_NR
603 depends on PROC_FS
604 help
605 This enables the /proc/pid/seccomp_cache interface to monitor
606 seccomp cache data. The file format is subject to change. Reading
607 the file requires CAP_SYS_ADMIN.
608
609 This option is for debugging only. Enabling presents the risk that
610 an adversary may be able to infer the seccomp filter logic.
611
612 If unsure, say N.
613
Alexander Popovafaef012018-08-17 01:16:58 +0300614config HAVE_ARCH_STACKLEAK
615 bool
616 help
617 An architecture should select this if it has the code which
618 fills the used part of the kernel stack with the STACKLEAK_POISON
619 value before returning from system calls.
620
Masahiro Yamadad148eac2018-06-14 19:36:45 +0900621config HAVE_STACKPROTECTOR
Kees Cook19952a92013-12-19 11:35:58 -0800622 bool
623 help
624 An arch should select this symbol if:
Kees Cook19952a92013-12-19 11:35:58 -0800625 - it has implemented a stack canary (e.g. __stack_chk_guard)
626
Linus Torvalds050e9ba2018-06-14 12:21:18 +0900627config STACKPROTECTOR
Masahiro Yamada2a61f472018-05-28 18:22:00 +0900628 bool "Stack Protector buffer overflow detection"
Masahiro Yamadad148eac2018-06-14 19:36:45 +0900629 depends on HAVE_STACKPROTECTOR
Masahiro Yamada2a61f472018-05-28 18:22:00 +0900630 depends on $(cc-option,-fstack-protector)
631 default y
Kees Cook87796572013-12-19 11:35:59 -0800632 help
633 This option turns on the "stack-protector" GCC feature. This
Kees Cook19952a92013-12-19 11:35:58 -0800634 feature puts, at the beginning of functions, a canary value on
635 the stack just before the return address, and validates
636 the value just before actually returning. Stack based buffer
637 overflows (that need to overwrite this return address) now also
638 overwrite the canary, which gets detected and the attack is then
639 neutralized via a kernel panic.
640
Kees Cook87796572013-12-19 11:35:59 -0800641 Functions will have the stack-protector canary logic added if they
642 have an 8-byte or larger character array on the stack.
643
Kees Cook19952a92013-12-19 11:35:58 -0800644 This feature requires gcc version 4.2 or above, or a distribution
Kees Cook87796572013-12-19 11:35:59 -0800645 gcc with the feature backported ("-fstack-protector").
646
647 On an x86 "defconfig" build, this feature adds canary checks to
648 about 3% of all kernel functions, which increases kernel code size
649 by about 0.3%.
650
Linus Torvalds050e9ba2018-06-14 12:21:18 +0900651config STACKPROTECTOR_STRONG
Masahiro Yamada2a61f472018-05-28 18:22:00 +0900652 bool "Strong Stack Protector"
Linus Torvalds050e9ba2018-06-14 12:21:18 +0900653 depends on STACKPROTECTOR
Masahiro Yamada2a61f472018-05-28 18:22:00 +0900654 depends on $(cc-option,-fstack-protector-strong)
655 default y
Kees Cook87796572013-12-19 11:35:59 -0800656 help
657 Functions will have the stack-protector canary logic added in any
658 of the following conditions:
659
660 - local variable's address used as part of the right hand side of an
661 assignment or function argument
662 - local variable is an array (or union containing an array),
663 regardless of array type or length
664 - uses register local variables
665
666 This feature requires gcc version 4.9 or above, or a distribution
667 gcc with the feature backported ("-fstack-protector-strong").
668
669 On an x86 "defconfig" build, this feature adds canary checks to
670 about 20% of all kernel functions, which increases the kernel code
671 size by about 2%.
672
Sami Tolvanend08b9f02020-04-27 09:00:07 -0700673config ARCH_SUPPORTS_SHADOW_CALL_STACK
674 bool
675 help
Dan Liafcf5442022-03-02 23:43:23 -0800676 An architecture should select this if it supports the compiler's
677 Shadow Call Stack and implements runtime support for shadow stack
Will Deaconaa7a65a2020-05-15 16:15:46 +0100678 switching.
Sami Tolvanend08b9f02020-04-27 09:00:07 -0700679
680config SHADOW_CALL_STACK
Dan Liafcf5442022-03-02 23:43:23 -0800681 bool "Shadow Call Stack"
682 depends on ARCH_SUPPORTS_SHADOW_CALL_STACK
Ard Biesheuvel38792972022-12-13 14:24:07 +0100683 depends on DYNAMIC_FTRACE_WITH_ARGS || DYNAMIC_FTRACE_WITH_REGS || !FUNCTION_GRAPH_TRACER
Sami Tolvanend08b9f02020-04-27 09:00:07 -0700684 help
Dan Liafcf5442022-03-02 23:43:23 -0800685 This option enables the compiler's Shadow Call Stack, which
686 uses a shadow stack to protect function return addresses from
687 being overwritten by an attacker. More information can be found
688 in the compiler's documentation:
Sami Tolvanend08b9f02020-04-27 09:00:07 -0700689
Dan Liafcf5442022-03-02 23:43:23 -0800690 - Clang: https://clang.llvm.org/docs/ShadowCallStack.html
691 - GCC: https://gcc.gnu.org/onlinedocs/gcc/Instrumentation-Options.html#Instrumentation-Options
Sami Tolvanend08b9f02020-04-27 09:00:07 -0700692
693 Note that security guarantees in the kernel differ from the
694 ones documented for user space. The kernel must store addresses
695 of shadow stacks in memory, which means an attacker capable of
696 reading and writing arbitrary memory may be able to locate them
697 and hijack control flow by modifying the stacks.
698
Ard Biesheuvel9beccca2022-10-27 17:59:07 +0200699config DYNAMIC_SCS
700 bool
701 help
702 Set by the arch code if it relies on code patching to insert the
703 shadow call stack push and pop instructions rather than on the
704 compiler.
705
Sami Tolvanendc5723b2020-12-11 10:46:19 -0800706config LTO
707 bool
708 help
709 Selected if the kernel will be built using the compiler's LTO feature.
710
711config LTO_CLANG
712 bool
713 select LTO
714 help
715 Selected if the kernel will be built using Clang's LTO feature.
716
717config ARCH_SUPPORTS_LTO_CLANG
718 bool
719 help
720 An architecture should select this option if it supports:
721 - compiling with Clang,
722 - compiling inline assembly with Clang's integrated assembler,
723 - and linking with LLD.
724
725config ARCH_SUPPORTS_LTO_CLANG_THIN
726 bool
727 help
728 An architecture should select this option if it can support Clang's
729 ThinLTO mode.
730
731config HAS_LTO_CLANG
732 def_bool y
Nathan Chancellor1e68a8af2021-11-29 09:58:00 -0700733 depends on CC_IS_CLANG && LD_IS_LLD && AS_IS_LLVM
Sami Tolvanendc5723b2020-12-11 10:46:19 -0800734 depends on $(success,$(NM) --help | head -n 1 | grep -qi llvm)
735 depends on $(success,$(AR) --help | head -n 1 | grep -qi llvm)
736 depends on ARCH_SUPPORTS_LTO_CLANG
737 depends on !FTRACE_MCOUNT_USE_RECORDMCOUNT
Jakob Koschel349fde52023-07-19 00:29:12 +0200738 # https://github.com/ClangBuiltLinux/linux/issues/1721
739 depends on (!KASAN || KASAN_HW_TAGS || CLANG_VERSION >= 170000) || !DEBUG_INFO
740 depends on (!KCOV || CLANG_VERSION >= 170000) || !DEBUG_INFO
Sami Tolvanendc5723b2020-12-11 10:46:19 -0800741 depends on !GCOV_KERNEL
Sami Tolvanendc5723b2020-12-11 10:46:19 -0800742 help
743 The compiler and Kconfig options support building with Clang's
744 LTO.
745
746choice
747 prompt "Link Time Optimization (LTO)"
748 default LTO_NONE
749 help
750 This option enables Link Time Optimization (LTO), which allows the
751 compiler to optimize binaries globally.
752
753 If unsure, select LTO_NONE. Note that LTO is very resource-intensive
754 so it's disabled by default.
755
756config LTO_NONE
757 bool "None"
758 help
759 Build the kernel normally, without Link Time Optimization (LTO).
760
761config LTO_CLANG_FULL
762 bool "Clang Full LTO (EXPERIMENTAL)"
763 depends on HAS_LTO_CLANG
764 depends on !COMPILE_TEST
765 select LTO_CLANG
766 help
Juerg Haefliger9f79ffc2023-02-01 17:24:35 +0100767 This option enables Clang's full Link Time Optimization (LTO), which
768 allows the compiler to optimize the kernel globally. If you enable
769 this option, the compiler generates LLVM bitcode instead of ELF
770 object files, and the actual compilation from bitcode happens at
771 the LTO link step, which may take several minutes depending on the
772 kernel configuration. More information can be found from LLVM's
773 documentation:
Sami Tolvanendc5723b2020-12-11 10:46:19 -0800774
775 https://llvm.org/docs/LinkTimeOptimization.html
776
777 During link time, this option can use a large amount of RAM, and
778 may take much longer than the ThinLTO option.
779
780config LTO_CLANG_THIN
781 bool "Clang ThinLTO (EXPERIMENTAL)"
782 depends on HAS_LTO_CLANG && ARCH_SUPPORTS_LTO_CLANG_THIN
783 select LTO_CLANG
784 help
785 This option enables Clang's ThinLTO, which allows for parallel
786 optimization and faster incremental compiles compared to the
787 CONFIG_LTO_CLANG_FULL option. More information can be found
788 from Clang's documentation:
789
790 https://clang.llvm.org/docs/ThinLTO.html
791
792 If unsure, say Y.
793endchoice
794
Sami Tolvanencf68fff2021-04-08 11:28:26 -0700795config ARCH_SUPPORTS_CFI_CLANG
796 bool
797 help
798 An architecture should select this option if it can support Clang's
799 Control-Flow Integrity (CFI) checking.
800
Sami Tolvanen89245602022-09-08 14:54:47 -0700801config ARCH_USES_CFI_TRAPS
802 bool
803
Sami Tolvanencf68fff2021-04-08 11:28:26 -0700804config CFI_CLANG
805 bool "Use Clang's Control Flow Integrity (CFI)"
Sami Tolvanen89245602022-09-08 14:54:47 -0700806 depends on ARCH_SUPPORTS_CFI_CLANG
807 depends on $(cc-option,-fsanitize=kcfi)
Sami Tolvanencf68fff2021-04-08 11:28:26 -0700808 help
809 This option enables Clang’s forward-edge Control Flow Integrity
810 (CFI) checking, where the compiler injects a runtime check to each
811 indirect function call to ensure the target is a valid function with
812 the correct static type. This restricts possible call targets and
813 makes it more difficult for an attacker to exploit bugs that allow
814 the modification of stored function pointers. More information can be
815 found from Clang's documentation:
816
817 https://clang.llvm.org/docs/ControlFlowIntegrity.html
818
Sami Tolvanencf68fff2021-04-08 11:28:26 -0700819config CFI_PERMISSIVE
820 bool "Use CFI in permissive mode"
821 depends on CFI_CLANG
822 help
823 When selected, Control Flow Integrity (CFI) violations result in a
824 warning instead of a kernel panic. This option should only be used
825 for finding indirect call type mismatches during development.
826
827 If unsure, say N.
828
Kees Cook0f60a8e2016-07-12 16:19:48 -0700829config HAVE_ARCH_WITHIN_STACK_FRAMES
830 bool
831 help
832 An architecture should select this if it can walk the kernel stack
833 frames to determine if an object is part of either the arguments
834 or local variables (i.e. that it excludes saved return addresses,
835 and similar) by implementing an inline arch_within_stack_frames(),
836 which is used by CONFIG_HARDENED_USERCOPY.
837
Frederic Weisbecker24a9c5412022-06-08 16:40:24 +0200838config HAVE_CONTEXT_TRACKING_USER
Frederic Weisbecker2b1d5022012-07-11 20:26:30 +0200839 bool
840 help
Frederic Weisbecker91d1aa432012-11-27 19:33:25 +0100841 Provide kernel/user boundaries probes necessary for subsystems
842 that need it, such as userspace RCU extended quiescent state.
Frederic Weisbecker490f5612020-01-27 16:41:52 +0100843 Syscalls need to be wrapped inside user_exit()-user_enter(), either
844 optimized behind static key or through the slow path using TIF_NOHZ
845 flag. Exceptions handlers must be wrapped as well. Irqs are already
Frederic Weisbecker6f0e6c12022-06-08 16:40:26 +0200846 protected inside ct_irq_enter/ct_irq_exit() but preemption or signal
Frederic Weisbecker490f5612020-01-27 16:41:52 +0100847 handling on irq exit still need to be protected.
848
Frederic Weisbecker24a9c5412022-06-08 16:40:24 +0200849config HAVE_CONTEXT_TRACKING_USER_OFFSTACK
Frederic Weisbecker83c2da22020-11-17 16:16:33 +0100850 bool
851 help
852 Architecture neither relies on exception_enter()/exception_exit()
853 nor on schedule_user(). Also preempt_schedule_notrace() and
854 preempt_schedule_irq() can't be called in a preemptible section
855 while context tracking is CONTEXT_USER. This feature reflects a sane
856 entry implementation where the following requirements are met on
857 critical entry code, ie: before user_exit() or after user_enter():
858
859 - Critical entry code isn't preemptible (or better yet:
860 not interruptible).
Frederic Weisbecker493c1822022-06-08 16:40:27 +0200861 - No use of RCU read side critical sections, unless ct_nmi_enter()
Frederic Weisbecker83c2da22020-11-17 16:16:33 +0100862 got called.
863 - No use of instrumentation, unless instrumentation_begin() got
864 called.
865
Frederic Weisbecker490f5612020-01-27 16:41:52 +0100866config HAVE_TIF_NOHZ
867 bool
868 help
869 Arch relies on TIF_NOHZ and syscall slow path to implement context
870 tracking calls to user_enter()/user_exit().
Frederic Weisbecker2b1d5022012-07-11 20:26:30 +0200871
Frederic Weisbeckerb9527412012-06-16 15:39:34 +0200872config HAVE_VIRT_CPU_ACCOUNTING
873 bool
874
Frederic Weisbecker2b91ec9f2020-12-02 12:57:29 +0100875config HAVE_VIRT_CPU_ACCOUNTING_IDLE
876 bool
877 help
878 Architecture has its own way to account idle CPU time and therefore
879 doesn't implement vtime_account_idle().
880
Stanislaw Gruszka40565b52016-11-15 03:06:51 +0100881config ARCH_HAS_SCALED_CPUTIME
882 bool
883
Kevin Hilman554b0002013-09-16 15:28:21 -0700884config HAVE_VIRT_CPU_ACCOUNTING_GEN
885 bool
886 default y if 64BIT
887 help
888 With VIRT_CPU_ACCOUNTING_GEN, cputime_t becomes 64-bit.
889 Before enabling this option, arch code must be audited
890 to ensure there are no races in concurrent read/write of
891 cputime_t. For example, reading/writing 64-bit cputime_t on
892 some 32-bit arches may require multiple accesses, so proper
893 locking is needed to protect against concurrent accesses.
894
Frederic Weisbeckerfdf9c352012-09-09 14:56:31 +0200895config HAVE_IRQ_TIME_ACCOUNTING
896 bool
897 help
898 Archs need to ensure they use a high enough resolution clock to
899 support irq time accounting and then call enable_sched_clock_irqtime().
900
Kalesh Singhc49dd342020-12-14 19:07:30 -0800901config HAVE_MOVE_PUD
902 bool
903 help
904 Architectures that select this are able to move page tables at the
905 PUD level. If there are only 3 page table levels, the move effectively
906 happens at the PGD level.
907
Joel Fernandes (Google)2c91bd4a2019-01-03 15:28:38 -0800908config HAVE_MOVE_PMD
909 bool
910 help
911 Archs that select this are able to move page tables at the PMD level.
912
Gerald Schaefer15626062012-10-08 16:30:04 -0700913config HAVE_ARCH_TRANSPARENT_HUGEPAGE
914 bool
915
Matthew Wilcoxa00cc7d2017-02-24 14:57:02 -0800916config HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
917 bool
918
Toshi Kani0ddab1d2015-04-14 15:47:20 -0700919config HAVE_ARCH_HUGE_VMAP
920 bool
921
Nicholas Piggin121e6f32021-04-29 22:58:49 -0700922#
923# Archs that select this would be capable of PMD-sized vmaps (i.e.,
Song Liu559089e2022-04-15 09:44:10 -0700924# arch_vmap_pmd_supported() returns true). The VM_ALLOW_HUGE_VMAP flag
925# must be used to enable allocations to use hugepages.
Nicholas Piggin121e6f32021-04-29 22:58:49 -0700926#
927config HAVE_ARCH_HUGE_VMALLOC
928 depends on HAVE_ARCH_HUGE_VMAP
929 bool
930
Alexandre Ghiti3876d4a2019-06-27 15:00:11 -0700931config ARCH_WANT_HUGE_PMD_SHARE
932 bool
933
Rick Edgecombe2f0584f2023-06-12 17:10:27 -0700934# Archs that want to use pmd_mkwrite on kernel memory need it defined even
935# if there are no userspace memory management features that use it
936config ARCH_WANT_KERNEL_PMD_MKWRITE
937 bool
938
939config ARCH_WANT_PMD_MKWRITE
940 def_bool TRANSPARENT_HUGEPAGE || ARCH_WANT_KERNEL_PMD_MKWRITE
941
Pavel Emelyanov0f8975e2013-07-03 15:01:20 -0700942config HAVE_ARCH_SOFT_DIRTY
943 bool
944
David Howells786d35d2012-09-28 14:31:03 +0930945config HAVE_MOD_ARCH_SPECIFIC
946 bool
947 help
948 The arch uses struct mod_arch_specific to store data. Many arches
949 just need a simple module loader without arch specific data - those
950 should not enable this.
951
952config MODULES_USE_ELF_RELA
953 bool
954 help
955 Modules only use ELF RELA relocations. Modules with ELF REL
956 relocations will give an error.
957
958config MODULES_USE_ELF_REL
959 bool
960 help
961 Modules only use ELF REL relocations. Modules with ELF RELA
962 relocations will give an error.
963
Christophe Leroy01dc0382022-02-23 13:02:14 +0100964config ARCH_WANTS_MODULES_DATA_IN_VMALLOC
965 bool
966 help
967 For architectures like powerpc/32 which have constraints on module
968 allocation and need to allocate module data outside of module area.
969
Frederic Weisbeckercc1f0272013-09-24 17:17:47 +0200970config HAVE_IRQ_EXIT_ON_IRQ_STACK
971 bool
972 help
973 Architecture doesn't only execute the irq handler on the irq stack
974 but also irq_exit(). This way we can process softirqs on this irq
975 stack instead of switching to a new one when we call __do_softirq()
976 in the end of an hardirq.
977 This spares a stack switch and improves cache usage on softirq
978 processing.
979
Thomas Gleixnercd1a41c2021-02-10 00:40:52 +0100980config HAVE_SOFTIRQ_ON_OWN_STACK
981 bool
982 help
983 Architecture provides a function to run __do_softirq() on a
Colin Ian Kingc226bc32021-09-07 19:57:38 -0700984 separate stack.
Thomas Gleixnercd1a41c2021-02-10 00:40:52 +0100985
Sebastian Andrzej Siewior8cbb2b52022-08-25 10:25:05 +0200986config SOFTIRQ_ON_OWN_STACK
987 def_bool HAVE_SOFTIRQ_ON_OWN_STACK && !PREEMPT_RT
988
Arnd Bergmann12700c12022-02-15 17:55:04 +0100989config ALTERNATE_USER_ADDRESS_SPACE
990 bool
991 help
992 Architectures set this when the CPU uses separate address
993 spaces for kernel and user space pointers. In this case, the
994 access_ok() check on a __user pointer is skipped.
995
Kirill A. Shutemov235a8f02015-04-14 15:46:17 -0700996config PGTABLE_LEVELS
997 int
998 default 2
999
Kees Cook2b68f6c2015-04-14 15:48:00 -07001000config ARCH_HAS_ELF_RANDOMIZE
1001 bool
1002 help
1003 An architecture supports choosing randomized locations for
1004 stack, mmap, brk, and ET_DYN. Defined functions:
1005 - arch_mmap_rnd()
Kees Cook204db6e2015-04-14 15:48:12 -07001006 - arch_randomize_brk()
Kees Cook2b68f6c2015-04-14 15:48:00 -07001007
Daniel Cashmand07e2252016-01-14 15:19:53 -08001008config HAVE_ARCH_MMAP_RND_BITS
1009 bool
1010 help
1011 An arch should select this symbol if it supports setting a variable
1012 number of bits for use in establishing the base address for mmap
1013 allocations, has MMU enabled and provides values for both:
1014 - ARCH_MMAP_RND_BITS_MIN
1015 - ARCH_MMAP_RND_BITS_MAX
1016
Jiri Slaby5f56a5d2016-05-20 17:00:16 -07001017config HAVE_EXIT_THREAD
1018 bool
1019 help
1020 An architecture implements exit_thread.
1021
Daniel Cashmand07e2252016-01-14 15:19:53 -08001022config ARCH_MMAP_RND_BITS_MIN
1023 int
1024
1025config ARCH_MMAP_RND_BITS_MAX
1026 int
1027
1028config ARCH_MMAP_RND_BITS_DEFAULT
1029 int
1030
1031config ARCH_MMAP_RND_BITS
1032 int "Number of bits to use for ASLR of mmap base address" if EXPERT
1033 range ARCH_MMAP_RND_BITS_MIN ARCH_MMAP_RND_BITS_MAX
1034 default ARCH_MMAP_RND_BITS_DEFAULT if ARCH_MMAP_RND_BITS_DEFAULT
1035 default ARCH_MMAP_RND_BITS_MIN
1036 depends on HAVE_ARCH_MMAP_RND_BITS
1037 help
1038 This value can be used to select the number of bits to use to
1039 determine the random offset to the base address of vma regions
1040 resulting from mmap allocations. This value will be bounded
1041 by the architecture's minimum and maximum supported values.
1042
1043 This value can be changed after boot using the
1044 /proc/sys/vm/mmap_rnd_bits tunable
1045
1046config HAVE_ARCH_MMAP_RND_COMPAT_BITS
1047 bool
1048 help
1049 An arch should select this symbol if it supports running applications
1050 in compatibility mode, supports setting a variable number of bits for
1051 use in establishing the base address for mmap allocations, has MMU
1052 enabled and provides values for both:
1053 - ARCH_MMAP_RND_COMPAT_BITS_MIN
1054 - ARCH_MMAP_RND_COMPAT_BITS_MAX
1055
1056config ARCH_MMAP_RND_COMPAT_BITS_MIN
1057 int
1058
1059config ARCH_MMAP_RND_COMPAT_BITS_MAX
1060 int
1061
1062config ARCH_MMAP_RND_COMPAT_BITS_DEFAULT
1063 int
1064
1065config ARCH_MMAP_RND_COMPAT_BITS
1066 int "Number of bits to use for ASLR of mmap base address for compatible applications" if EXPERT
1067 range ARCH_MMAP_RND_COMPAT_BITS_MIN ARCH_MMAP_RND_COMPAT_BITS_MAX
1068 default ARCH_MMAP_RND_COMPAT_BITS_DEFAULT if ARCH_MMAP_RND_COMPAT_BITS_DEFAULT
1069 default ARCH_MMAP_RND_COMPAT_BITS_MIN
1070 depends on HAVE_ARCH_MMAP_RND_COMPAT_BITS
1071 help
1072 This value can be used to select the number of bits to use to
1073 determine the random offset to the base address of vma regions
1074 resulting from mmap allocations for compatible applications This
1075 value will be bounded by the architecture's minimum and maximum
1076 supported values.
1077
1078 This value can be changed after boot using the
1079 /proc/sys/vm/mmap_rnd_compat_bits tunable
1080
Dmitry Safonov1b028f72017-03-06 17:17:19 +03001081config HAVE_ARCH_COMPAT_MMAP_BASES
1082 bool
1083 help
1084 This allows 64bit applications to invoke 32-bit mmap() syscall
1085 and vice-versa 32-bit applications to call 64-bit mmap().
1086 Required for applications doing different bitness syscalls.
1087
Guenter Roeck1f0e2902021-11-27 07:44:40 -08001088config PAGE_SIZE_LESS_THAN_64KB
1089 def_bool y
1090 depends on !ARM64_64K_PAGES
Guenter Roeck1f0e2902021-11-27 07:44:40 -08001091 depends on !PAGE_SIZE_64KB
1092 depends on !PARISC_PAGE_SIZE_64KB
Nathan Chancellore4bbd202022-01-19 18:10:22 -08001093 depends on PAGE_SIZE_LESS_THAN_256KB
1094
1095config PAGE_SIZE_LESS_THAN_256KB
1096 def_bool y
Guenter Roeck1f0e2902021-11-27 07:44:40 -08001097 depends on !PAGE_SIZE_256KB
1098
Alexandre Ghiti67f39772019-09-23 15:38:47 -07001099# This allows to use a set of generic functions to determine mmap base
1100# address by giving priority to top-down scheme only if the process
1101# is not in legacy mode (compat task, unlimited stack size or
1102# sysctl_legacy_va_layout).
1103# Architecture that selects this option can provide its own version of:
1104# - STACK_RND_MASK
1105config ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT
1106 bool
1107 depends on MMU
Alexandre Ghitie7142bf2019-09-23 15:38:50 -07001108 select ARCH_HAS_ELF_RANDOMIZE
Alexandre Ghiti67f39772019-09-23 15:38:47 -07001109
Josh Poimboeuf03f16cd2022-04-18 09:50:36 -07001110config HAVE_OBJTOOL
1111 bool
1112
Josh Poimboeuf4ab76742022-04-18 09:50:39 -07001113config HAVE_JUMP_LABEL_HACK
1114 bool
1115
Josh Poimboeuf22102f42022-04-18 09:50:40 -07001116config HAVE_NOINSTR_HACK
1117 bool
1118
Josh Poimboeuf489e3552022-04-18 09:50:42 -07001119config HAVE_NOINSTR_VALIDATION
1120 bool
1121
Josh Poimboeuf5f3da8c2022-04-19 09:05:09 -07001122config HAVE_UACCESS_VALIDATION
1123 bool
1124 select OBJTOOL
1125
Josh Poimboeufb9ab5eb2016-02-28 22:22:42 -06001126config HAVE_STACK_VALIDATION
1127 bool
1128 help
Josh Poimboeuf03f16cd2022-04-18 09:50:36 -07001129 Architecture supports objtool compile-time frame pointer rule
1130 validation.
Josh Poimboeufb9ab5eb2016-02-28 22:22:42 -06001131
Josh Poimboeufaf085d92017-02-13 19:42:28 -06001132config HAVE_RELIABLE_STACKTRACE
1133 bool
1134 help
Miroslav Benes140d7e82020-03-05 22:28:45 -08001135 Architecture has either save_stack_trace_tsk_reliable() or
1136 arch_stack_walk_reliable() function which only returns a stack trace
1137 if it can guarantee the trace is reliable.
Josh Poimboeufaf085d92017-02-13 19:42:28 -06001138
George Spelvin468a9422016-05-26 22:11:51 -04001139config HAVE_ARCH_HASH
1140 bool
1141 default n
1142 help
1143 If this is set, the architecture provides an <asm/hash.h>
1144 file which provides platform-specific implementations of some
1145 functions in <linux/hash.h> or fs/namei.c.
1146
Finn Thain666047fe2019-01-15 15:18:56 +11001147config HAVE_ARCH_NVRAM_OPS
1148 bool
1149
William Breathitt Gray3a495512016-05-27 18:08:27 -04001150config ISA_BUS_API
1151 def_bool ISA
1152
Al Virod2125042012-10-23 13:17:59 -04001153#
1154# ABI hall of shame
1155#
1156config CLONE_BACKWARDS
1157 bool
1158 help
1159 Architecture has tls passed as the 4th argument of clone(2),
1160 not the 5th one.
1161
1162config CLONE_BACKWARDS2
1163 bool
1164 help
1165 Architecture has the first two arguments of clone(2) swapped.
1166
Michal Simekdfa97712013-08-13 16:00:53 -07001167config CLONE_BACKWARDS3
1168 bool
1169 help
1170 Architecture has tls passed as the 3rd argument of clone(2),
1171 not the 5th one.
1172
Al Viroeaca6ea2012-11-25 23:12:10 -05001173config ODD_RT_SIGACTION
1174 bool
1175 help
1176 Architecture has unusual rt_sigaction(2) arguments
1177
Al Viro0a0e8cd2012-12-25 16:04:12 -05001178config OLD_SIGSUSPEND
1179 bool
1180 help
1181 Architecture has old sigsuspend(2) syscall, of one-argument variety
1182
1183config OLD_SIGSUSPEND3
1184 bool
1185 help
1186 Even weirder antique ABI - three-argument sigsuspend(2)
1187
Al Viro495dfbf2012-12-25 19:09:45 -05001188config OLD_SIGACTION
1189 bool
1190 help
1191 Architecture has old sigaction(2) syscall. Nope, not the same
1192 as OLD_SIGSUSPEND | OLD_SIGSUSPEND3 - alpha has sigsuspend(2),
1193 but fairly different variant of sigaction(2), thanks to OSF/1
1194 compatibility...
1195
1196config COMPAT_OLD_SIGACTION
1197 bool
1198
Deepa Dinamani17435e52018-03-13 21:03:28 -07001199config COMPAT_32BIT_TIME
Arnd Bergmann942437c2019-07-15 11:46:10 +02001200 bool "Provide system calls for 32-bit time_t"
1201 default !64BIT || COMPAT
Deepa Dinamani17435e52018-03-13 21:03:28 -07001202 help
1203 This enables 32 bit time_t support in addition to 64 bit time_t support.
1204 This is relevant on all 32-bit architectures, and 64-bit architectures
1205 as part of compat syscall handling.
1206
Christoph Hellwig87a4c372018-07-31 13:39:32 +02001207config ARCH_NO_PREEMPT
1208 bool
1209
Thomas Gleixnera50a3f42019-07-17 22:01:49 +02001210config ARCH_SUPPORTS_RT
1211 bool
1212
Zhaoxiu Zengfff7fb02016-05-20 17:03:57 -07001213config CPU_NO_EFFICIENT_FFS
1214 def_bool n
1215
Andy Lutomirskiba14a192016-08-11 02:35:21 -07001216config HAVE_ARCH_VMAP_STACK
1217 def_bool n
1218 help
1219 An arch should select this symbol if it can support kernel stacks
1220 in vmalloc space. This means:
1221
1222 - vmalloc space must be large enough to hold many kernel stacks.
1223 This may rule out many 32-bit architectures.
1224
1225 - Stacks in vmalloc space need to work reliably. For example, if
1226 vmap page tables are created on demand, either this mechanism
1227 needs to work while the stack points to a virtual address with
1228 unpopulated page tables or arch code (switch_to() and switch_mm(),
1229 most likely) needs to ensure that the stack's page table entries
1230 are populated before running on a possibly unpopulated stack.
1231
1232 - If the stack overflows into a guard page, something reasonable
1233 should happen. The definition of "reasonable" is flexible, but
1234 instantly rebooting without logging anything would be unfriendly.
1235
1236config VMAP_STACK
1237 default y
1238 bool "Use a virtually-mapped stack"
Daniel Axtenseafb1492019-11-30 17:54:57 -08001239 depends on HAVE_ARCH_VMAP_STACK
Andrey Konovalov38dd767d2020-12-22 12:02:45 -08001240 depends on !KASAN || KASAN_HW_TAGS || KASAN_VMALLOC
Masahiro Yamadaa7f7f622020-06-14 01:50:22 +09001241 help
Andy Lutomirskiba14a192016-08-11 02:35:21 -07001242 Enable this if you want the use virtually-mapped kernel stacks
1243 with guard pages. This causes kernel stack overflows to be
1244 caught immediately rather than causing difficult-to-diagnose
1245 corruption.
1246
Andrey Konovalov38dd767d2020-12-22 12:02:45 -08001247 To use this with software KASAN modes, the architecture must support
1248 backing virtual mappings with real shadow memory, and KASAN_VMALLOC
1249 must be enabled.
Andy Lutomirskiba14a192016-08-11 02:35:21 -07001250
Kees Cook39218ff2021-04-01 16:23:44 -07001251config HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET
1252 def_bool n
1253 help
1254 An arch should select this symbol if it can support kernel stack
1255 offset randomization with calls to add_random_kstack_offset()
1256 during syscall entry and choose_random_kstack_offset() during
1257 syscall exit. Careful removal of -fstack-protector-strong and
1258 -fstack-protector should also be applied to the entry code and
1259 closely examined, as the artificial stack bump looks like an array
1260 to the compiler, so it will attempt to add canary checks regardless
1261 of the static branch state.
1262
Marco Elver8cb37a52022-01-31 10:05:20 +01001263config RANDOMIZE_KSTACK_OFFSET
1264 bool "Support for randomizing kernel stack offset on syscall entry" if EXPERT
1265 default y
Kees Cook39218ff2021-04-01 16:23:44 -07001266 depends on HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET
Marco Elverefa90c12022-01-31 10:05:21 +01001267 depends on INIT_STACK_NONE || !CC_IS_CLANG || CLANG_VERSION >= 140000
Kees Cook39218ff2021-04-01 16:23:44 -07001268 help
1269 The kernel stack offset can be randomized (after pt_regs) by
1270 roughly 5 bits of entropy, frustrating memory corruption
1271 attacks that depend on stack address determinism or
Marco Elver8cb37a52022-01-31 10:05:20 +01001272 cross-syscall address exposures.
1273
1274 The feature is controlled via the "randomize_kstack_offset=on/off"
1275 kernel boot param, and if turned off has zero overhead due to its use
1276 of static branches (see JUMP_LABEL).
1277
1278 If unsure, say Y.
1279
1280config RANDOMIZE_KSTACK_OFFSET_DEFAULT
1281 bool "Default state of kernel stack offset randomization"
1282 depends on RANDOMIZE_KSTACK_OFFSET
1283 help
1284 Kernel stack offset randomization is controlled by kernel boot param
1285 "randomize_kstack_offset=on/off", and this config chooses the default
1286 boot state.
Kees Cook39218ff2021-04-01 16:23:44 -07001287
Laura Abbottad21fc42017-02-06 16:31:57 -08001288config ARCH_OPTIONAL_KERNEL_RWX
1289 def_bool n
1290
1291config ARCH_OPTIONAL_KERNEL_RWX_DEFAULT
1292 def_bool n
1293
1294config ARCH_HAS_STRICT_KERNEL_RWX
1295 def_bool n
1296
Laura Abbott0f5bf6d2017-02-06 16:31:58 -08001297config STRICT_KERNEL_RWX
Laura Abbottad21fc42017-02-06 16:31:57 -08001298 bool "Make kernel text and rodata read-only" if ARCH_OPTIONAL_KERNEL_RWX
1299 depends on ARCH_HAS_STRICT_KERNEL_RWX
1300 default !ARCH_OPTIONAL_KERNEL_RWX || ARCH_OPTIONAL_KERNEL_RWX_DEFAULT
1301 help
1302 If this is set, kernel text and rodata memory will be made read-only,
1303 and non-text memory will be made non-executable. This provides
1304 protection against certain security exploits (e.g. executing the heap
1305 or modifying text)
1306
1307 These features are considered standard security practice these days.
1308 You should say Y here in almost all cases.
1309
1310config ARCH_HAS_STRICT_MODULE_RWX
1311 def_bool n
1312
Laura Abbott0f5bf6d2017-02-06 16:31:58 -08001313config STRICT_MODULE_RWX
Laura Abbottad21fc42017-02-06 16:31:57 -08001314 bool "Set loadable kernel module data as NX and text as RO" if ARCH_OPTIONAL_KERNEL_RWX
1315 depends on ARCH_HAS_STRICT_MODULE_RWX && MODULES
1316 default !ARCH_OPTIONAL_KERNEL_RWX || ARCH_OPTIONAL_KERNEL_RWX_DEFAULT
1317 help
1318 If this is set, module text and rodata memory will be made read-only,
1319 and non-text memory will be made non-executable. This provides
1320 protection against certain security exploits (e.g. writing to text)
1321
Christoph Hellwigea8c64a2018-01-10 16:21:13 +01001322# select if the architecture provides an asm/dma-direct.h header
1323config ARCH_HAS_PHYS_TO_DMA
1324 bool
1325
Paul Burton04f264d2018-08-20 15:36:17 -07001326config HAVE_ARCH_COMPILER_H
1327 bool
1328 help
1329 An architecture can select this if it provides an
1330 asm/compiler.h header that should be included after
1331 linux/compiler-*.h in order to override macro definitions that those
1332 headers generally provide.
1333
Ard Biesheuvel271ca782018-08-21 21:56:00 -07001334config HAVE_ARCH_PREL32_RELOCATIONS
1335 bool
1336 help
1337 May be selected by an architecture if it supports place-relative
1338 32-bit relocations, both in the toolchain and in the module loader,
1339 in which case relative references can be used in special sections
1340 for PCI fixup, initcalls etc which are only half the size on 64 bit
1341 architectures, and don't require runtime relocation on relocatable
1342 kernels.
1343
Ard Biesheuvelce9084b2019-02-02 10:41:17 +01001344config ARCH_USE_MEMREMAP_PROT
1345 bool
1346
Waiman Longfb346fd2019-04-04 13:43:17 -04001347config LOCK_EVENT_COUNTS
1348 bool "Locking event counts collection"
1349 depends on DEBUG_FS
Masahiro Yamadaa7f7f622020-06-14 01:50:22 +09001350 help
Waiman Longfb346fd2019-04-04 13:43:17 -04001351 Enable light-weight counting of various locking related events
1352 in the system with minimal performance impact. This reduces
1353 the chance of application behavior change because of timing
1354 differences. The counts are reported via debugfs.
1355
Peter Collingbourne5cf896fb62019-07-31 18:18:42 -07001356# Select if the architecture has support for applying RELR relocations.
1357config ARCH_HAS_RELR
1358 bool
1359
1360config RELR
1361 bool "Use RELR relocation packing"
1362 depends on ARCH_HAS_RELR && TOOLS_SUPPORT_RELR
1363 default y
1364 help
1365 Store the kernel's dynamic relocations in the RELR relocation packing
1366 format. Requires a compatible linker (LLD supports this feature), as
1367 well as compatible NM and OBJCOPY utilities (llvm-nm and llvm-objcopy
1368 are compatible).
1369
Thiago Jung Bauermann0c9c1d52019-08-06 01:49:14 -03001370config ARCH_HAS_MEM_ENCRYPT
1371 bool
1372
Tom Lendacky46b49b12021-09-08 17:58:33 -05001373config ARCH_HAS_CC_PLATFORM
1374 bool
1375
Hassan Naveed0e242202019-11-15 23:44:42 +00001376config HAVE_SPARSE_SYSCALL_NR
Juerg Haefliger9f79ffc2023-02-01 17:24:35 +01001377 bool
1378 help
1379 An architecture should select this if its syscall numbering is sparse
Hassan Naveed0e242202019-11-15 23:44:42 +00001380 to save space. For example, MIPS architecture has a syscall array with
1381 entries at 4000, 5000 and 6000 locations. This option turns on syscall
1382 related optimizations for a given architecture.
1383
Sven Schnelled60d7de2020-08-04 17:01:22 +02001384config ARCH_HAS_VDSO_DATA
1385 bool
1386
Josh Poimboeuf115284d2020-08-18 15:57:41 +02001387config HAVE_STATIC_CALL
1388 bool
1389
Josh Poimboeuf9183c3f2020-08-18 15:57:42 +02001390config HAVE_STATIC_CALL_INLINE
1391 bool
1392 depends on HAVE_STATIC_CALL
Josh Poimboeuf03f16cd2022-04-18 09:50:36 -07001393 select OBJTOOL
Josh Poimboeuf9183c3f2020-08-18 15:57:42 +02001394
Michal Hocko6ef869e2021-01-18 15:12:19 +01001395config HAVE_PREEMPT_DYNAMIC
1396 bool
Mark Rutland99cf983c2022-02-14 16:52:14 +00001397
1398config HAVE_PREEMPT_DYNAMIC_CALL
1399 bool
Michal Hocko6ef869e2021-01-18 15:12:19 +01001400 depends on HAVE_STATIC_CALL
Mark Rutland99cf983c2022-02-14 16:52:14 +00001401 select HAVE_PREEMPT_DYNAMIC
Michal Hocko6ef869e2021-01-18 15:12:19 +01001402 help
Juerg Haefliger9f79ffc2023-02-01 17:24:35 +01001403 An architecture should select this if it can handle the preemption
1404 model being selected at boot time using static calls.
Mark Rutland99cf983c2022-02-14 16:52:14 +00001405
Juerg Haefliger9f79ffc2023-02-01 17:24:35 +01001406 Where an architecture selects HAVE_STATIC_CALL_INLINE, any call to a
1407 preemption function will be patched directly.
Mark Rutland99cf983c2022-02-14 16:52:14 +00001408
Juerg Haefliger9f79ffc2023-02-01 17:24:35 +01001409 Where an architecture does not select HAVE_STATIC_CALL_INLINE, any
1410 call to a preemption function will go through a trampoline, and the
1411 trampoline will be patched.
Mark Rutland99cf983c2022-02-14 16:52:14 +00001412
Juerg Haefliger9f79ffc2023-02-01 17:24:35 +01001413 It is strongly advised to support inline static call to avoid any
1414 overhead.
Mark Rutland99cf983c2022-02-14 16:52:14 +00001415
1416config HAVE_PREEMPT_DYNAMIC_KEY
1417 bool
Nick Desaulniersa0a12c32022-08-19 12:06:40 -07001418 depends on HAVE_ARCH_JUMP_LABEL
Mark Rutland99cf983c2022-02-14 16:52:14 +00001419 select HAVE_PREEMPT_DYNAMIC
1420 help
Juerg Haefliger9f79ffc2023-02-01 17:24:35 +01001421 An architecture should select this if it can handle the preemption
1422 model being selected at boot time using static keys.
Mark Rutland99cf983c2022-02-14 16:52:14 +00001423
Juerg Haefliger9f79ffc2023-02-01 17:24:35 +01001424 Each preemption function will be given an early return based on a
1425 static key. This should have slightly lower overhead than non-inline
1426 static calls, as this effectively inlines each trampoline into the
1427 start of its callee. This may avoid redundant work, and may
1428 integrate better with CFI schemes.
Mark Rutland99cf983c2022-02-14 16:52:14 +00001429
Juerg Haefliger9f79ffc2023-02-01 17:24:35 +01001430 This will have greater overhead than using inline static calls as
1431 the call to the preemption function cannot be entirely elided.
Michal Hocko6ef869e2021-01-18 15:12:19 +01001432
Nathan Chancellor59612b22020-11-19 13:46:56 -07001433config ARCH_WANT_LD_ORPHAN_WARN
1434 bool
1435 help
1436 An arch should select this symbol once all linker sections are explicitly
1437 included, size-asserted, or discarded in the linker scripts. This is
1438 important because we never want expected sections to be placed heuristically
1439 by the linker, since the locations of such sections can change between linker
1440 versions.
1441
Mike Rapoport4f5b0c12020-12-14 19:09:59 -08001442config HAVE_ARCH_PFN_VALID
1443 bool
1444
Mike Rapoport5d6ad662020-12-14 19:10:30 -08001445config ARCH_SUPPORTS_DEBUG_PAGEALLOC
1446 bool
1447
Pasha Tatashindf4e8172022-01-14 14:06:37 -08001448config ARCH_SUPPORTS_PAGE_TABLE_CHECK
1449 bool
1450
Brian Gerst2ca408d2020-11-30 17:30:59 -05001451config ARCH_SPLIT_ARG64
1452 bool
1453 help
Juerg Haefliger9f79ffc2023-02-01 17:24:35 +01001454 If a 32-bit architecture requires 64-bit arguments to be split into
1455 pairs of 32-bit arguments, select this option.
Brian Gerst2ca408d2020-11-30 17:30:59 -05001456
Al Viro7facdc42020-06-13 23:03:25 -04001457config ARCH_HAS_ELFCORE_COMPAT
1458 bool
1459
Balbir Singh58e106e2021-04-26 21:59:11 +02001460config ARCH_HAS_PARANOID_L1D_FLUSH
1461 bool
1462
Prasad Sodagudid593d642022-05-18 22:14:14 +05301463config ARCH_HAVE_TRACE_MMIO_ACCESS
1464 bool
1465
Thomas Gleixner1bdda242021-10-21 15:55:05 -07001466config DYNAMIC_SIGFRAME
1467 bool
1468
Jarkko Sakkinen50468e42021-11-16 18:21:16 +02001469# Select, if arch has a named attribute group bound to NUMA device nodes.
1470config HAVE_ARCH_NODE_DEV_GROUP
1471 bool
1472
Yu Zhaoeed9a322022-09-18 01:59:59 -06001473config ARCH_HAS_NONLEAF_PMD_YOUNG
1474 bool
1475 help
1476 Architectures that select this option are capable of setting the
1477 accessed bit in non-leaf PMD entries when using them as part of linear
1478 address translations. Page table walkers that clear the accessed bit
1479 may use this capability to reduce their search space.
1480
Peter Oberparleiter2521f2c2009-06-17 16:28:08 -07001481source "kernel/gcov/Kconfig"
Masahiro Yamada45332b12018-07-05 15:24:12 +09001482
1483source "scripts/gcc-plugins/Kconfig"
Linus Torvaldsfa1b5d02018-08-15 13:05:12 -07001484
Peter Zijlstrad49a0622022-09-15 13:10:47 +02001485config FUNCTION_ALIGNMENT_4B
1486 bool
1487
1488config FUNCTION_ALIGNMENT_8B
1489 bool
1490
1491config FUNCTION_ALIGNMENT_16B
1492 bool
1493
1494config FUNCTION_ALIGNMENT_32B
1495 bool
1496
1497config FUNCTION_ALIGNMENT_64B
1498 bool
1499
1500config FUNCTION_ALIGNMENT
1501 int
1502 default 64 if FUNCTION_ALIGNMENT_64B
1503 default 32 if FUNCTION_ALIGNMENT_32B
1504 default 16 if FUNCTION_ALIGNMENT_16B
1505 default 8 if FUNCTION_ALIGNMENT_8B
1506 default 4 if FUNCTION_ALIGNMENT_4B
1507 default 0
1508
Randy Dunlap22471e12018-07-31 13:39:33 +02001509endmenu