Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 1 | /* |
Jason Wessel | 53197fc | 2010-04-02 11:48:03 -0500 | [diff] [blame] | 2 | * Kernel Debug Core |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 3 | * |
| 4 | * Maintainer: Jason Wessel <jason.wessel@windriver.com> |
| 5 | * |
| 6 | * Copyright (C) 2000-2001 VERITAS Software Corporation. |
| 7 | * Copyright (C) 2002-2004 Timesys Corporation |
| 8 | * Copyright (C) 2003-2004 Amit S. Kale <amitkale@linsyssoft.com> |
Pavel Machek | a253129 | 2010-07-18 14:27:13 +0200 | [diff] [blame] | 9 | * Copyright (C) 2004 Pavel Machek <pavel@ucw.cz> |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 10 | * Copyright (C) 2004-2006 Tom Rini <trini@kernel.crashing.org> |
| 11 | * Copyright (C) 2004-2006 LinSysSoft Technologies Pvt. Ltd. |
Jason Wessel | 53197fc | 2010-04-02 11:48:03 -0500 | [diff] [blame] | 12 | * Copyright (C) 2005-2009 Wind River Systems, Inc. |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 13 | * Copyright (C) 2007 MontaVista Software, Inc. |
| 14 | * Copyright (C) 2008 Red Hat, Inc., Ingo Molnar <mingo@redhat.com> |
| 15 | * |
| 16 | * Contributors at various stages not listed above: |
| 17 | * Jason Wessel ( jason.wessel@windriver.com ) |
| 18 | * George Anzinger <george@mvista.com> |
| 19 | * Anurekh Saxena (anurekh.saxena@timesys.com) |
| 20 | * Lake Stevens Instrument Division (Glenn Engel) |
| 21 | * Jim Kingdon, Cygnus Support. |
| 22 | * |
| 23 | * Original KGDB stub: David Grothe <dave@gcom.com>, |
| 24 | * Tigran Aivazian <tigran@sco.com> |
| 25 | * |
| 26 | * This file is licensed under the terms of the GNU General Public License |
| 27 | * version 2. This program is licensed "as is" without any warranty of any |
| 28 | * kind, whether express or implied. |
| 29 | */ |
Fabian Frederick | 0f16996 | 2014-06-12 21:30:11 +0200 | [diff] [blame] | 30 | |
| 31 | #define pr_fmt(fmt) "KGDB: " fmt |
| 32 | |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 33 | #include <linux/pid_namespace.h> |
Jason Wessel | 7c3078b | 2008-02-15 14:55:54 -0600 | [diff] [blame] | 34 | #include <linux/clocksource.h> |
Greg Kroah-Hartman | 16559ae | 2013-02-04 15:35:26 -0800 | [diff] [blame] | 35 | #include <linux/serial_core.h> |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 36 | #include <linux/interrupt.h> |
| 37 | #include <linux/spinlock.h> |
| 38 | #include <linux/console.h> |
| 39 | #include <linux/threads.h> |
| 40 | #include <linux/uaccess.h> |
| 41 | #include <linux/kernel.h> |
| 42 | #include <linux/module.h> |
| 43 | #include <linux/ptrace.h> |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 44 | #include <linux/string.h> |
| 45 | #include <linux/delay.h> |
| 46 | #include <linux/sched.h> |
| 47 | #include <linux/sysrq.h> |
Jason Wessel | 2366e04 | 2012-03-16 14:20:41 -0500 | [diff] [blame] | 48 | #include <linux/reboot.h> |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 49 | #include <linux/init.h> |
| 50 | #include <linux/kgdb.h> |
Jason Wessel | dcc7871 | 2010-05-20 21:04:21 -0500 | [diff] [blame] | 51 | #include <linux/kdb.h> |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 52 | #include <linux/pid.h> |
| 53 | #include <linux/smp.h> |
| 54 | #include <linux/mm.h> |
Davidlohr Bueso | 615d6e8 | 2014-04-07 15:37:25 -0700 | [diff] [blame] | 55 | #include <linux/vmacache.h> |
Jason Wessel | fb70b58 | 2010-08-13 12:44:04 -0500 | [diff] [blame] | 56 | #include <linux/rcupdate.h> |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 57 | |
| 58 | #include <asm/cacheflush.h> |
| 59 | #include <asm/byteorder.h> |
Arun Sharma | 60063497 | 2011-07-26 16:09:06 -0700 | [diff] [blame] | 60 | #include <linux/atomic.h> |
Jason Wessel | 53197fc | 2010-04-02 11:48:03 -0500 | [diff] [blame] | 61 | |
| 62 | #include "debug_core.h" |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 63 | |
| 64 | static int kgdb_break_asap; |
| 65 | |
Jason Wessel | 53197fc | 2010-04-02 11:48:03 -0500 | [diff] [blame] | 66 | struct debuggerinfo_struct kgdb_info[NR_CPUS]; |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 67 | |
| 68 | /** |
| 69 | * kgdb_connected - Is a host GDB connected to us? |
| 70 | */ |
| 71 | int kgdb_connected; |
| 72 | EXPORT_SYMBOL_GPL(kgdb_connected); |
| 73 | |
| 74 | /* All the KGDB handlers are installed */ |
Jason Wessel | f503b5a | 2010-05-20 21:04:25 -0500 | [diff] [blame] | 75 | int kgdb_io_module_registered; |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 76 | |
| 77 | /* Guard for recursive entry */ |
| 78 | static int exception_level; |
| 79 | |
Jason Wessel | 53197fc | 2010-04-02 11:48:03 -0500 | [diff] [blame] | 80 | struct kgdb_io *dbg_io_ops; |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 81 | static DEFINE_SPINLOCK(kgdb_registration_lock); |
| 82 | |
Jason Wessel | bec4d62 | 2012-03-19 19:35:55 -0500 | [diff] [blame] | 83 | /* Action for the reboot notifiter, a global allow kdb to change it */ |
| 84 | static int kgdbreboot; |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 85 | /* kgdb console driver is loaded */ |
| 86 | static int kgdb_con_registered; |
| 87 | /* determine if kgdb console output should be used */ |
| 88 | static int kgdb_use_con; |
Jason Wessel | 0b4b382 | 2010-05-20 21:04:29 -0500 | [diff] [blame] | 89 | /* Flag for alternate operations for early debugging */ |
| 90 | bool dbg_is_early = true; |
Jason Wessel | dcc7871 | 2010-05-20 21:04:21 -0500 | [diff] [blame] | 91 | /* Next cpu to become the master debug core */ |
| 92 | int dbg_switch_cpu; |
| 93 | |
| 94 | /* Use kdb or gdbserver mode */ |
Jason Wessel | a0de055 | 2010-05-20 21:04:24 -0500 | [diff] [blame] | 95 | int dbg_kdb_mode = 1; |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 96 | |
| 97 | static int __init opt_kgdb_con(char *str) |
| 98 | { |
| 99 | kgdb_use_con = 1; |
| 100 | return 0; |
| 101 | } |
| 102 | |
| 103 | early_param("kgdbcon", opt_kgdb_con); |
| 104 | |
| 105 | module_param(kgdb_use_con, int, 0644); |
Jason Wessel | bec4d62 | 2012-03-19 19:35:55 -0500 | [diff] [blame] | 106 | module_param(kgdbreboot, int, 0644); |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 107 | |
| 108 | /* |
| 109 | * Holds information about breakpoints in a kernel. These breakpoints are |
| 110 | * added and removed by gdb. |
| 111 | */ |
| 112 | static struct kgdb_bkpt kgdb_break[KGDB_MAX_BREAKPOINTS] = { |
| 113 | [0 ... KGDB_MAX_BREAKPOINTS-1] = { .state = BP_UNDEFINED } |
| 114 | }; |
| 115 | |
| 116 | /* |
| 117 | * The CPU# of the active CPU, or -1 if none: |
| 118 | */ |
| 119 | atomic_t kgdb_active = ATOMIC_INIT(-1); |
Jason Wessel | dcc7871 | 2010-05-20 21:04:21 -0500 | [diff] [blame] | 120 | EXPORT_SYMBOL_GPL(kgdb_active); |
Jason Wessel | dfee3a7 | 2010-05-21 08:46:00 -0500 | [diff] [blame] | 121 | static DEFINE_RAW_SPINLOCK(dbg_master_lock); |
| 122 | static DEFINE_RAW_SPINLOCK(dbg_slave_lock); |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 123 | |
| 124 | /* |
| 125 | * We use NR_CPUs not PERCPU, in case kgdb is used to debug early |
| 126 | * bootup code (which might not have percpu set up yet): |
| 127 | */ |
Jason Wessel | dfee3a7 | 2010-05-21 08:46:00 -0500 | [diff] [blame] | 128 | static atomic_t masters_in_kgdb; |
| 129 | static atomic_t slaves_in_kgdb; |
Jason Wessel | 1cee5e3 | 2009-06-03 14:06:57 -0500 | [diff] [blame] | 130 | static atomic_t kgdb_break_tasklet_var; |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 131 | atomic_t kgdb_setting_breakpoint; |
| 132 | |
| 133 | struct task_struct *kgdb_usethread; |
| 134 | struct task_struct *kgdb_contthread; |
| 135 | |
| 136 | int kgdb_single_step; |
Jason Wessel | 53197fc | 2010-04-02 11:48:03 -0500 | [diff] [blame] | 137 | static pid_t kgdb_sstep_pid; |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 138 | |
| 139 | /* to keep track of the CPU which is doing the single stepping*/ |
| 140 | atomic_t kgdb_cpu_doing_single_step = ATOMIC_INIT(-1); |
| 141 | |
| 142 | /* |
| 143 | * If you are debugging a problem where roundup (the collection of |
| 144 | * all other CPUs) is a problem [this should be extremely rare], |
| 145 | * then use the nokgdbroundup option to avoid roundup. In that case |
| 146 | * the other CPUs might interfere with your debugging context, so |
| 147 | * use this with care: |
| 148 | */ |
Harvey Harrison | 688b744 | 2008-04-24 16:57:23 -0500 | [diff] [blame] | 149 | static int kgdb_do_roundup = 1; |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 150 | |
| 151 | static int __init opt_nokgdbroundup(char *str) |
| 152 | { |
| 153 | kgdb_do_roundup = 0; |
| 154 | |
| 155 | return 0; |
| 156 | } |
| 157 | |
| 158 | early_param("nokgdbroundup", opt_nokgdbroundup); |
| 159 | |
| 160 | /* |
| 161 | * Finally, some KGDB code :-) |
| 162 | */ |
| 163 | |
| 164 | /* |
| 165 | * Weak aliases for breakpoint management, |
| 166 | * can be overriden by architectures when needed: |
| 167 | */ |
Jason Wessel | 98b54aa | 2012-03-21 10:17:03 -0500 | [diff] [blame] | 168 | int __weak kgdb_arch_set_breakpoint(struct kgdb_bkpt *bpt) |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 169 | { |
| 170 | int err; |
| 171 | |
Jason Wessel | 98b54aa | 2012-03-21 10:17:03 -0500 | [diff] [blame] | 172 | err = probe_kernel_read(bpt->saved_instr, (char *)bpt->bpt_addr, |
| 173 | BREAK_INSTR_SIZE); |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 174 | if (err) |
| 175 | return err; |
Jason Wessel | 98b54aa | 2012-03-21 10:17:03 -0500 | [diff] [blame] | 176 | err = probe_kernel_write((char *)bpt->bpt_addr, |
| 177 | arch_kgdb_ops.gdb_bpt_instr, BREAK_INSTR_SIZE); |
| 178 | return err; |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 179 | } |
| 180 | |
Jason Wessel | 98b54aa | 2012-03-21 10:17:03 -0500 | [diff] [blame] | 181 | int __weak kgdb_arch_remove_breakpoint(struct kgdb_bkpt *bpt) |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 182 | { |
Jason Wessel | 98b54aa | 2012-03-21 10:17:03 -0500 | [diff] [blame] | 183 | return probe_kernel_write((char *)bpt->bpt_addr, |
| 184 | (char *)bpt->saved_instr, BREAK_INSTR_SIZE); |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 185 | } |
| 186 | |
Jason Wessel | a9b60bf | 2008-08-01 08:39:34 -0500 | [diff] [blame] | 187 | int __weak kgdb_validate_break_address(unsigned long addr) |
| 188 | { |
Jason Wessel | 98b54aa | 2012-03-21 10:17:03 -0500 | [diff] [blame] | 189 | struct kgdb_bkpt tmp; |
Jason Wessel | a9b60bf | 2008-08-01 08:39:34 -0500 | [diff] [blame] | 190 | int err; |
Jason Wessel | 98b54aa | 2012-03-21 10:17:03 -0500 | [diff] [blame] | 191 | /* Validate setting the breakpoint and then removing it. If the |
Jason Wessel | a9b60bf | 2008-08-01 08:39:34 -0500 | [diff] [blame] | 192 | * remove fails, the kernel needs to emit a bad message because we |
| 193 | * are deep trouble not being able to put things back the way we |
| 194 | * found them. |
| 195 | */ |
Jason Wessel | 98b54aa | 2012-03-21 10:17:03 -0500 | [diff] [blame] | 196 | tmp.bpt_addr = addr; |
| 197 | err = kgdb_arch_set_breakpoint(&tmp); |
Jason Wessel | a9b60bf | 2008-08-01 08:39:34 -0500 | [diff] [blame] | 198 | if (err) |
| 199 | return err; |
Jason Wessel | 98b54aa | 2012-03-21 10:17:03 -0500 | [diff] [blame] | 200 | err = kgdb_arch_remove_breakpoint(&tmp); |
Jason Wessel | a9b60bf | 2008-08-01 08:39:34 -0500 | [diff] [blame] | 201 | if (err) |
Fabian Frederick | 0f16996 | 2014-06-12 21:30:11 +0200 | [diff] [blame] | 202 | pr_err("Critical breakpoint error, kernel memory destroyed at: %lx\n", |
| 203 | addr); |
Jason Wessel | a9b60bf | 2008-08-01 08:39:34 -0500 | [diff] [blame] | 204 | return err; |
| 205 | } |
| 206 | |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 207 | unsigned long __weak kgdb_arch_pc(int exception, struct pt_regs *regs) |
| 208 | { |
| 209 | return instruction_pointer(regs); |
| 210 | } |
| 211 | |
| 212 | int __weak kgdb_arch_init(void) |
| 213 | { |
| 214 | return 0; |
| 215 | } |
| 216 | |
Jason Wessel | b4b8ac5 | 2008-02-20 13:33:38 -0600 | [diff] [blame] | 217 | int __weak kgdb_skipexception(int exception, struct pt_regs *regs) |
| 218 | { |
| 219 | return 0; |
| 220 | } |
| 221 | |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 222 | /* |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 223 | * Some architectures need cache flushes when we set/clear a |
| 224 | * breakpoint: |
| 225 | */ |
| 226 | static void kgdb_flush_swbreak_addr(unsigned long addr) |
| 227 | { |
| 228 | if (!CACHE_FLUSH_IS_SAFE) |
| 229 | return; |
| 230 | |
Davidlohr Bueso | 615d6e8 | 2014-04-07 15:37:25 -0700 | [diff] [blame] | 231 | if (current->mm) { |
| 232 | int i; |
| 233 | |
| 234 | for (i = 0; i < VMACACHE_SIZE; i++) { |
| 235 | if (!current->vmacache[i]) |
| 236 | continue; |
| 237 | flush_cache_range(current->vmacache[i], |
| 238 | addr, addr + BREAK_INSTR_SIZE); |
| 239 | } |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 240 | } |
Davidlohr Bueso | 615d6e8 | 2014-04-07 15:37:25 -0700 | [diff] [blame] | 241 | |
Jason Wessel | 1a9a3e7 | 2008-04-01 16:55:28 -0500 | [diff] [blame] | 242 | /* Force flush instruction cache if it was outside the mm */ |
| 243 | flush_icache_range(addr, addr + BREAK_INSTR_SIZE); |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 244 | } |
| 245 | |
| 246 | /* |
| 247 | * SW breakpoint management: |
| 248 | */ |
Jason Wessel | 53197fc | 2010-04-02 11:48:03 -0500 | [diff] [blame] | 249 | int dbg_activate_sw_breakpoints(void) |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 250 | { |
Jason Wessel | 7f8b7ed6 | 2009-12-11 08:43:20 -0600 | [diff] [blame] | 251 | int error; |
| 252 | int ret = 0; |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 253 | int i; |
| 254 | |
| 255 | for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { |
| 256 | if (kgdb_break[i].state != BP_SET) |
| 257 | continue; |
| 258 | |
Jason Wessel | 98b54aa | 2012-03-21 10:17:03 -0500 | [diff] [blame] | 259 | error = kgdb_arch_set_breakpoint(&kgdb_break[i]); |
Jason Wessel | 7f8b7ed6 | 2009-12-11 08:43:20 -0600 | [diff] [blame] | 260 | if (error) { |
| 261 | ret = error; |
Fabian Frederick | 0f16996 | 2014-06-12 21:30:11 +0200 | [diff] [blame] | 262 | pr_info("BP install failed: %lx\n", |
| 263 | kgdb_break[i].bpt_addr); |
Jason Wessel | 7f8b7ed6 | 2009-12-11 08:43:20 -0600 | [diff] [blame] | 264 | continue; |
| 265 | } |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 266 | |
Jason Wessel | 98b54aa | 2012-03-21 10:17:03 -0500 | [diff] [blame] | 267 | kgdb_flush_swbreak_addr(kgdb_break[i].bpt_addr); |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 268 | kgdb_break[i].state = BP_ACTIVE; |
| 269 | } |
Jason Wessel | 7f8b7ed6 | 2009-12-11 08:43:20 -0600 | [diff] [blame] | 270 | return ret; |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 271 | } |
| 272 | |
Jason Wessel | 53197fc | 2010-04-02 11:48:03 -0500 | [diff] [blame] | 273 | int dbg_set_sw_break(unsigned long addr) |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 274 | { |
| 275 | int err = kgdb_validate_break_address(addr); |
| 276 | int breakno = -1; |
| 277 | int i; |
| 278 | |
| 279 | if (err) |
| 280 | return err; |
| 281 | |
| 282 | for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { |
| 283 | if ((kgdb_break[i].state == BP_SET) && |
| 284 | (kgdb_break[i].bpt_addr == addr)) |
| 285 | return -EEXIST; |
| 286 | } |
| 287 | for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { |
| 288 | if (kgdb_break[i].state == BP_REMOVED && |
| 289 | kgdb_break[i].bpt_addr == addr) { |
| 290 | breakno = i; |
| 291 | break; |
| 292 | } |
| 293 | } |
| 294 | |
| 295 | if (breakno == -1) { |
| 296 | for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { |
| 297 | if (kgdb_break[i].state == BP_UNDEFINED) { |
| 298 | breakno = i; |
| 299 | break; |
| 300 | } |
| 301 | } |
| 302 | } |
| 303 | |
| 304 | if (breakno == -1) |
| 305 | return -E2BIG; |
| 306 | |
| 307 | kgdb_break[breakno].state = BP_SET; |
| 308 | kgdb_break[breakno].type = BP_BREAKPOINT; |
| 309 | kgdb_break[breakno].bpt_addr = addr; |
| 310 | |
| 311 | return 0; |
| 312 | } |
| 313 | |
Jason Wessel | dcc7871 | 2010-05-20 21:04:21 -0500 | [diff] [blame] | 314 | int dbg_deactivate_sw_breakpoints(void) |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 315 | { |
Jason Wessel | 7f8b7ed6 | 2009-12-11 08:43:20 -0600 | [diff] [blame] | 316 | int error; |
| 317 | int ret = 0; |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 318 | int i; |
| 319 | |
| 320 | for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { |
| 321 | if (kgdb_break[i].state != BP_ACTIVE) |
| 322 | continue; |
Jason Wessel | 98b54aa | 2012-03-21 10:17:03 -0500 | [diff] [blame] | 323 | error = kgdb_arch_remove_breakpoint(&kgdb_break[i]); |
Jason Wessel | 7f8b7ed6 | 2009-12-11 08:43:20 -0600 | [diff] [blame] | 324 | if (error) { |
Fabian Frederick | 0f16996 | 2014-06-12 21:30:11 +0200 | [diff] [blame] | 325 | pr_info("BP remove failed: %lx\n", |
| 326 | kgdb_break[i].bpt_addr); |
Jason Wessel | 7f8b7ed6 | 2009-12-11 08:43:20 -0600 | [diff] [blame] | 327 | ret = error; |
| 328 | } |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 329 | |
Jason Wessel | 98b54aa | 2012-03-21 10:17:03 -0500 | [diff] [blame] | 330 | kgdb_flush_swbreak_addr(kgdb_break[i].bpt_addr); |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 331 | kgdb_break[i].state = BP_SET; |
| 332 | } |
Jason Wessel | 7f8b7ed6 | 2009-12-11 08:43:20 -0600 | [diff] [blame] | 333 | return ret; |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 334 | } |
| 335 | |
Jason Wessel | 53197fc | 2010-04-02 11:48:03 -0500 | [diff] [blame] | 336 | int dbg_remove_sw_break(unsigned long addr) |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 337 | { |
| 338 | int i; |
| 339 | |
| 340 | for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { |
| 341 | if ((kgdb_break[i].state == BP_SET) && |
| 342 | (kgdb_break[i].bpt_addr == addr)) { |
| 343 | kgdb_break[i].state = BP_REMOVED; |
| 344 | return 0; |
| 345 | } |
| 346 | } |
| 347 | return -ENOENT; |
| 348 | } |
| 349 | |
| 350 | int kgdb_isremovedbreak(unsigned long addr) |
| 351 | { |
| 352 | int i; |
| 353 | |
| 354 | for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { |
| 355 | if ((kgdb_break[i].state == BP_REMOVED) && |
| 356 | (kgdb_break[i].bpt_addr == addr)) |
| 357 | return 1; |
| 358 | } |
| 359 | return 0; |
| 360 | } |
| 361 | |
Jason Wessel | 53197fc | 2010-04-02 11:48:03 -0500 | [diff] [blame] | 362 | int dbg_remove_all_break(void) |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 363 | { |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 364 | int error; |
| 365 | int i; |
| 366 | |
| 367 | /* Clear memory breakpoints. */ |
| 368 | for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { |
Jason Wessel | 737a460 | 2008-03-07 16:34:16 -0600 | [diff] [blame] | 369 | if (kgdb_break[i].state != BP_ACTIVE) |
| 370 | goto setundefined; |
Jason Wessel | 98b54aa | 2012-03-21 10:17:03 -0500 | [diff] [blame] | 371 | error = kgdb_arch_remove_breakpoint(&kgdb_break[i]); |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 372 | if (error) |
Fabian Frederick | 0f16996 | 2014-06-12 21:30:11 +0200 | [diff] [blame] | 373 | pr_err("breakpoint remove failed: %lx\n", |
Jason Wessel | 98b54aa | 2012-03-21 10:17:03 -0500 | [diff] [blame] | 374 | kgdb_break[i].bpt_addr); |
Jason Wessel | 737a460 | 2008-03-07 16:34:16 -0600 | [diff] [blame] | 375 | setundefined: |
| 376 | kgdb_break[i].state = BP_UNDEFINED; |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 377 | } |
| 378 | |
| 379 | /* Clear hardware breakpoints. */ |
| 380 | if (arch_kgdb_ops.remove_all_hw_break) |
| 381 | arch_kgdb_ops.remove_all_hw_break(); |
| 382 | |
| 383 | return 0; |
| 384 | } |
| 385 | |
| 386 | /* |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 387 | * Return true if there is a valid kgdb I/O module. Also if no |
| 388 | * debugger is attached a message can be printed to the console about |
| 389 | * waiting for the debugger to attach. |
| 390 | * |
| 391 | * The print_wait argument is only to be true when called from inside |
| 392 | * the core kgdb_handle_exception, because it will wait for the |
| 393 | * debugger to attach. |
| 394 | */ |
| 395 | static int kgdb_io_ready(int print_wait) |
| 396 | { |
Jason Wessel | 53197fc | 2010-04-02 11:48:03 -0500 | [diff] [blame] | 397 | if (!dbg_io_ops) |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 398 | return 0; |
| 399 | if (kgdb_connected) |
| 400 | return 1; |
| 401 | if (atomic_read(&kgdb_setting_breakpoint)) |
| 402 | return 1; |
Jason Wessel | dcc7871 | 2010-05-20 21:04:21 -0500 | [diff] [blame] | 403 | if (print_wait) { |
| 404 | #ifdef CONFIG_KGDB_KDB |
| 405 | if (!dbg_kdb_mode) |
Fabian Frederick | 0f16996 | 2014-06-12 21:30:11 +0200 | [diff] [blame] | 406 | pr_crit("waiting... or $3#33 for KDB\n"); |
Jason Wessel | dcc7871 | 2010-05-20 21:04:21 -0500 | [diff] [blame] | 407 | #else |
Fabian Frederick | 0f16996 | 2014-06-12 21:30:11 +0200 | [diff] [blame] | 408 | pr_crit("Waiting for remote debugger\n"); |
Jason Wessel | dcc7871 | 2010-05-20 21:04:21 -0500 | [diff] [blame] | 409 | #endif |
| 410 | } |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 411 | return 1; |
| 412 | } |
| 413 | |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 414 | static int kgdb_reenter_check(struct kgdb_state *ks) |
| 415 | { |
| 416 | unsigned long addr; |
| 417 | |
| 418 | if (atomic_read(&kgdb_active) != raw_smp_processor_id()) |
| 419 | return 0; |
| 420 | |
| 421 | /* Panic on recursive debugger calls: */ |
| 422 | exception_level++; |
| 423 | addr = kgdb_arch_pc(ks->ex_vector, ks->linux_regs); |
Jason Wessel | dcc7871 | 2010-05-20 21:04:21 -0500 | [diff] [blame] | 424 | dbg_deactivate_sw_breakpoints(); |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 425 | |
| 426 | /* |
| 427 | * If the break point removed ok at the place exception |
| 428 | * occurred, try to recover and print a warning to the end |
| 429 | * user because the user planted a breakpoint in a place that |
| 430 | * KGDB needs in order to function. |
| 431 | */ |
Jason Wessel | 53197fc | 2010-04-02 11:48:03 -0500 | [diff] [blame] | 432 | if (dbg_remove_sw_break(addr) == 0) { |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 433 | exception_level = 0; |
| 434 | kgdb_skipexception(ks->ex_vector, ks->linux_regs); |
Jason Wessel | 53197fc | 2010-04-02 11:48:03 -0500 | [diff] [blame] | 435 | dbg_activate_sw_breakpoints(); |
Fabian Frederick | 0f16996 | 2014-06-12 21:30:11 +0200 | [diff] [blame] | 436 | pr_crit("re-enter error: breakpoint removed %lx\n", addr); |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 437 | WARN_ON_ONCE(1); |
| 438 | |
| 439 | return 1; |
| 440 | } |
Jason Wessel | 53197fc | 2010-04-02 11:48:03 -0500 | [diff] [blame] | 441 | dbg_remove_all_break(); |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 442 | kgdb_skipexception(ks->ex_vector, ks->linux_regs); |
| 443 | |
| 444 | if (exception_level > 1) { |
| 445 | dump_stack(); |
| 446 | panic("Recursive entry to debugger"); |
| 447 | } |
| 448 | |
Fabian Frederick | 0f16996 | 2014-06-12 21:30:11 +0200 | [diff] [blame] | 449 | pr_crit("re-enter exception: ALL breakpoints killed\n"); |
Jason Wessel | 6d90634 | 2010-05-20 21:04:27 -0500 | [diff] [blame] | 450 | #ifdef CONFIG_KGDB_KDB |
| 451 | /* Allow kdb to debug itself one level */ |
| 452 | return 0; |
| 453 | #endif |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 454 | dump_stack(); |
| 455 | panic("Recursive entry to debugger"); |
| 456 | |
| 457 | return 1; |
| 458 | } |
| 459 | |
Jason Wessel | 16cdc62 | 2010-08-06 11:47:14 -0500 | [diff] [blame] | 460 | static void dbg_touch_watchdogs(void) |
| 461 | { |
| 462 | touch_softlockup_watchdog_sync(); |
| 463 | clocksource_touch_watchdog(); |
Jason Wessel | fb70b58 | 2010-08-13 12:44:04 -0500 | [diff] [blame] | 464 | rcu_cpu_stall_reset(); |
Jason Wessel | 16cdc62 | 2010-08-06 11:47:14 -0500 | [diff] [blame] | 465 | } |
| 466 | |
Jason Wessel | dfee3a7 | 2010-05-21 08:46:00 -0500 | [diff] [blame] | 467 | static int kgdb_cpu_enter(struct kgdb_state *ks, struct pt_regs *regs, |
| 468 | int exception_state) |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 469 | { |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 470 | unsigned long flags; |
Jason Wessel | 028e7b1 | 2009-12-11 08:43:17 -0600 | [diff] [blame] | 471 | int sstep_tries = 100; |
Jason Wessel | dcc7871 | 2010-05-20 21:04:21 -0500 | [diff] [blame] | 472 | int error; |
Jason Wessel | dfee3a7 | 2010-05-21 08:46:00 -0500 | [diff] [blame] | 473 | int cpu; |
Jason Wessel | 4da75b9 | 2010-04-02 11:57:18 -0500 | [diff] [blame] | 474 | int trace_on = 0; |
Jason Wessel | dfee3a7 | 2010-05-21 08:46:00 -0500 | [diff] [blame] | 475 | int online_cpus = num_online_cpus(); |
Daniel Thompson | a1465d2 | 2014-11-11 09:31:53 -0600 | [diff] [blame] | 476 | u64 time_left; |
Dongdong Deng | c1bb9a9 | 2010-09-13 06:58:00 -0500 | [diff] [blame] | 477 | |
Jason Wessel | dfee3a7 | 2010-05-21 08:46:00 -0500 | [diff] [blame] | 478 | kgdb_info[ks->cpu].enter_kgdb++; |
| 479 | kgdb_info[ks->cpu].exception_state |= exception_state; |
| 480 | |
| 481 | if (exception_state == DCPU_WANT_MASTER) |
| 482 | atomic_inc(&masters_in_kgdb); |
| 483 | else |
| 484 | atomic_inc(&slaves_in_kgdb); |
Dongdong Deng | d7ba979d | 2010-08-18 06:02:00 -0500 | [diff] [blame] | 485 | |
| 486 | if (arch_kgdb_ops.disable_hw_break) |
| 487 | arch_kgdb_ops.disable_hw_break(regs); |
Dongdong Deng | c1bb9a9 | 2010-09-13 06:58:00 -0500 | [diff] [blame] | 488 | |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 489 | acquirelock: |
| 490 | /* |
| 491 | * Interrupts will be restored by the 'trap return' code, except when |
| 492 | * single stepping. |
| 493 | */ |
| 494 | local_irq_save(flags); |
| 495 | |
Jason Wessel | 62fae31 | 2010-04-02 11:47:02 -0500 | [diff] [blame] | 496 | cpu = ks->cpu; |
| 497 | kgdb_info[cpu].debuggerinfo = regs; |
| 498 | kgdb_info[cpu].task = current; |
Jason Wessel | dcc7871 | 2010-05-20 21:04:21 -0500 | [diff] [blame] | 499 | kgdb_info[cpu].ret_state = 0; |
| 500 | kgdb_info[cpu].irq_depth = hardirq_count() >> HARDIRQ_SHIFT; |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 501 | |
Jason Wessel | dfee3a7 | 2010-05-21 08:46:00 -0500 | [diff] [blame] | 502 | /* Make sure the above info reaches the primary CPU */ |
| 503 | smp_mb(); |
| 504 | |
| 505 | if (exception_level == 1) { |
| 506 | if (raw_spin_trylock(&dbg_master_lock)) |
| 507 | atomic_xchg(&kgdb_active, cpu); |
Jason Wessel | 6d90634 | 2010-05-20 21:04:27 -0500 | [diff] [blame] | 508 | goto cpu_master_loop; |
Jason Wessel | dfee3a7 | 2010-05-21 08:46:00 -0500 | [diff] [blame] | 509 | } |
Jason Wessel | 6d90634 | 2010-05-20 21:04:27 -0500 | [diff] [blame] | 510 | |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 511 | /* |
Jason Wessel | 62fae31 | 2010-04-02 11:47:02 -0500 | [diff] [blame] | 512 | * CPU will loop if it is a slave or request to become a kgdb |
| 513 | * master cpu and acquire the kgdb_active lock: |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 514 | */ |
Jason Wessel | 62fae31 | 2010-04-02 11:47:02 -0500 | [diff] [blame] | 515 | while (1) { |
Jason Wessel | dcc7871 | 2010-05-20 21:04:21 -0500 | [diff] [blame] | 516 | cpu_loop: |
| 517 | if (kgdb_info[cpu].exception_state & DCPU_NEXT_MASTER) { |
| 518 | kgdb_info[cpu].exception_state &= ~DCPU_NEXT_MASTER; |
| 519 | goto cpu_master_loop; |
| 520 | } else if (kgdb_info[cpu].exception_state & DCPU_WANT_MASTER) { |
Jason Wessel | dfee3a7 | 2010-05-21 08:46:00 -0500 | [diff] [blame] | 521 | if (raw_spin_trylock(&dbg_master_lock)) { |
| 522 | atomic_xchg(&kgdb_active, cpu); |
Jason Wessel | 62fae31 | 2010-04-02 11:47:02 -0500 | [diff] [blame] | 523 | break; |
Jason Wessel | dfee3a7 | 2010-05-21 08:46:00 -0500 | [diff] [blame] | 524 | } |
Jason Wessel | 62fae31 | 2010-04-02 11:47:02 -0500 | [diff] [blame] | 525 | } else if (kgdb_info[cpu].exception_state & DCPU_IS_SLAVE) { |
Jason Wessel | dfee3a7 | 2010-05-21 08:46:00 -0500 | [diff] [blame] | 526 | if (!raw_spin_is_locked(&dbg_slave_lock)) |
Jason Wessel | 62fae31 | 2010-04-02 11:47:02 -0500 | [diff] [blame] | 527 | goto return_normal; |
| 528 | } else { |
| 529 | return_normal: |
| 530 | /* Return to normal operation by executing any |
| 531 | * hw breakpoint fixup. |
| 532 | */ |
| 533 | if (arch_kgdb_ops.correct_hw_break) |
| 534 | arch_kgdb_ops.correct_hw_break(); |
Jason Wessel | 4da75b9 | 2010-04-02 11:57:18 -0500 | [diff] [blame] | 535 | if (trace_on) |
| 536 | tracing_on(); |
Jason Wessel | dfee3a7 | 2010-05-21 08:46:00 -0500 | [diff] [blame] | 537 | kgdb_info[cpu].exception_state &= |
| 538 | ~(DCPU_WANT_MASTER | DCPU_IS_SLAVE); |
| 539 | kgdb_info[cpu].enter_kgdb--; |
Peter Zijlstra | 4e857c5 | 2014-03-17 18:06:10 +0100 | [diff] [blame] | 540 | smp_mb__before_atomic(); |
Jason Wessel | dfee3a7 | 2010-05-21 08:46:00 -0500 | [diff] [blame] | 541 | atomic_dec(&slaves_in_kgdb); |
Jason Wessel | 16cdc62 | 2010-08-06 11:47:14 -0500 | [diff] [blame] | 542 | dbg_touch_watchdogs(); |
Jason Wessel | 62fae31 | 2010-04-02 11:47:02 -0500 | [diff] [blame] | 543 | local_irq_restore(flags); |
| 544 | return 0; |
| 545 | } |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 546 | cpu_relax(); |
Jason Wessel | 62fae31 | 2010-04-02 11:47:02 -0500 | [diff] [blame] | 547 | } |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 548 | |
| 549 | /* |
Jason Wessel | 028e7b1 | 2009-12-11 08:43:17 -0600 | [diff] [blame] | 550 | * For single stepping, try to only enter on the processor |
Lucas De Marchi | 25985ed | 2011-03-30 22:57:33 -0300 | [diff] [blame] | 551 | * that was single stepping. To guard against a deadlock, the |
Jason Wessel | 028e7b1 | 2009-12-11 08:43:17 -0600 | [diff] [blame] | 552 | * kernel will only try for the value of sstep_tries before |
| 553 | * giving up and continuing on. |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 554 | */ |
| 555 | if (atomic_read(&kgdb_cpu_doing_single_step) != -1 && |
Jason Wessel | 028e7b1 | 2009-12-11 08:43:17 -0600 | [diff] [blame] | 556 | (kgdb_info[cpu].task && |
| 557 | kgdb_info[cpu].task->pid != kgdb_sstep_pid) && --sstep_tries) { |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 558 | atomic_set(&kgdb_active, -1); |
Jason Wessel | dfee3a7 | 2010-05-21 08:46:00 -0500 | [diff] [blame] | 559 | raw_spin_unlock(&dbg_master_lock); |
Jason Wessel | 16cdc62 | 2010-08-06 11:47:14 -0500 | [diff] [blame] | 560 | dbg_touch_watchdogs(); |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 561 | local_irq_restore(flags); |
| 562 | |
| 563 | goto acquirelock; |
| 564 | } |
| 565 | |
| 566 | if (!kgdb_io_ready(1)) { |
Jason Wessel | dcc7871 | 2010-05-20 21:04:21 -0500 | [diff] [blame] | 567 | kgdb_info[cpu].ret_state = 1; |
Jason Wessel | 53197fc | 2010-04-02 11:48:03 -0500 | [diff] [blame] | 568 | goto kgdb_restore; /* No I/O connection, resume the system */ |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 569 | } |
| 570 | |
| 571 | /* |
| 572 | * Don't enter if we have hit a removed breakpoint. |
| 573 | */ |
| 574 | if (kgdb_skipexception(ks->ex_vector, ks->linux_regs)) |
| 575 | goto kgdb_restore; |
| 576 | |
| 577 | /* Call the I/O driver's pre_exception routine */ |
Jason Wessel | 53197fc | 2010-04-02 11:48:03 -0500 | [diff] [blame] | 578 | if (dbg_io_ops->pre_exception) |
| 579 | dbg_io_ops->pre_exception(); |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 580 | |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 581 | /* |
| 582 | * Get the passive CPU lock which will hold all the non-primary |
| 583 | * CPU in a spin state while the debugger is active |
| 584 | */ |
Jason Wessel | dfee3a7 | 2010-05-21 08:46:00 -0500 | [diff] [blame] | 585 | if (!kgdb_single_step) |
| 586 | raw_spin_lock(&dbg_slave_lock); |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 587 | |
Jason Wessel | 56fb709 | 2008-04-01 16:55:27 -0500 | [diff] [blame] | 588 | #ifdef CONFIG_SMP |
Mike Travis | 8daaa5f | 2013-10-02 10:14:18 -0500 | [diff] [blame] | 589 | /* If send_ready set, slaves are already waiting */ |
| 590 | if (ks->send_ready) |
| 591 | atomic_set(ks->send_ready, 1); |
| 592 | |
Jason Wessel | 56fb709 | 2008-04-01 16:55:27 -0500 | [diff] [blame] | 593 | /* Signal the other CPUs to enter kgdb_wait() */ |
Mike Travis | 8daaa5f | 2013-10-02 10:14:18 -0500 | [diff] [blame] | 594 | else if ((!kgdb_single_step) && kgdb_do_roundup) |
Jason Wessel | 56fb709 | 2008-04-01 16:55:27 -0500 | [diff] [blame] | 595 | kgdb_roundup_cpus(flags); |
| 596 | #endif |
| 597 | |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 598 | /* |
| 599 | * Wait for the other CPUs to be notified and be waiting for us: |
| 600 | */ |
Daniel Thompson | a1465d2 | 2014-11-11 09:31:53 -0600 | [diff] [blame] | 601 | time_left = loops_per_jiffy * HZ; |
| 602 | while (kgdb_do_roundup && --time_left && |
| 603 | (atomic_read(&masters_in_kgdb) + atomic_read(&slaves_in_kgdb)) != |
| 604 | online_cpus) |
Jason Wessel | dfee3a7 | 2010-05-21 08:46:00 -0500 | [diff] [blame] | 605 | cpu_relax(); |
Daniel Thompson | a1465d2 | 2014-11-11 09:31:53 -0600 | [diff] [blame] | 606 | if (!time_left) |
Jason Wessel | df0036d | 2015-01-08 15:46:55 -0600 | [diff] [blame] | 607 | pr_crit("Timed out waiting for secondary CPUs.\n"); |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 608 | |
| 609 | /* |
| 610 | * At this point the primary processor is completely |
| 611 | * in the debugger and all secondary CPUs are quiescent |
| 612 | */ |
Jason Wessel | dcc7871 | 2010-05-20 21:04:21 -0500 | [diff] [blame] | 613 | dbg_deactivate_sw_breakpoints(); |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 614 | kgdb_single_step = 0; |
Jason Wessel | d7161a6 | 2008-09-26 10:36:41 -0500 | [diff] [blame] | 615 | kgdb_contthread = current; |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 616 | exception_level = 0; |
Jason Wessel | 4da75b9 | 2010-04-02 11:57:18 -0500 | [diff] [blame] | 617 | trace_on = tracing_is_on(); |
| 618 | if (trace_on) |
| 619 | tracing_off(); |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 620 | |
Jason Wessel | dcc7871 | 2010-05-20 21:04:21 -0500 | [diff] [blame] | 621 | while (1) { |
| 622 | cpu_master_loop: |
| 623 | if (dbg_kdb_mode) { |
| 624 | kgdb_connected = 1; |
| 625 | error = kdb_stub(ks); |
Jason Wessel | 3fa43ab | 2010-08-05 09:22:25 -0500 | [diff] [blame] | 626 | if (error == -1) |
| 627 | continue; |
Jason Wessel | b0679c6 | 2010-07-21 19:27:07 -0500 | [diff] [blame] | 628 | kgdb_connected = 0; |
Jason Wessel | dcc7871 | 2010-05-20 21:04:21 -0500 | [diff] [blame] | 629 | } else { |
| 630 | error = gdb_serial_stub(ks); |
| 631 | } |
| 632 | |
| 633 | if (error == DBG_PASS_EVENT) { |
| 634 | dbg_kdb_mode = !dbg_kdb_mode; |
Jason Wessel | dcc7871 | 2010-05-20 21:04:21 -0500 | [diff] [blame] | 635 | } else if (error == DBG_SWITCH_CPU_EVENT) { |
Jason Wessel | 495363d | 2010-05-21 08:46:00 -0500 | [diff] [blame] | 636 | kgdb_info[dbg_switch_cpu].exception_state |= |
| 637 | DCPU_NEXT_MASTER; |
Jason Wessel | dcc7871 | 2010-05-20 21:04:21 -0500 | [diff] [blame] | 638 | goto cpu_loop; |
| 639 | } else { |
| 640 | kgdb_info[cpu].ret_state = error; |
| 641 | break; |
| 642 | } |
| 643 | } |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 644 | |
| 645 | /* Call the I/O driver's post_exception routine */ |
Jason Wessel | 53197fc | 2010-04-02 11:48:03 -0500 | [diff] [blame] | 646 | if (dbg_io_ops->post_exception) |
| 647 | dbg_io_ops->post_exception(); |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 648 | |
Jason Wessel | d7161a6 | 2008-09-26 10:36:41 -0500 | [diff] [blame] | 649 | if (!kgdb_single_step) { |
Jason Wessel | dfee3a7 | 2010-05-21 08:46:00 -0500 | [diff] [blame] | 650 | raw_spin_unlock(&dbg_slave_lock); |
| 651 | /* Wait till all the CPUs have quit from the debugger. */ |
| 652 | while (kgdb_do_roundup && atomic_read(&slaves_in_kgdb)) |
| 653 | cpu_relax(); |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 654 | } |
| 655 | |
| 656 | kgdb_restore: |
Jason Wessel | 028e7b1 | 2009-12-11 08:43:17 -0600 | [diff] [blame] | 657 | if (atomic_read(&kgdb_cpu_doing_single_step) != -1) { |
| 658 | int sstep_cpu = atomic_read(&kgdb_cpu_doing_single_step); |
| 659 | if (kgdb_info[sstep_cpu].task) |
| 660 | kgdb_sstep_pid = kgdb_info[sstep_cpu].task->pid; |
| 661 | else |
| 662 | kgdb_sstep_pid = 0; |
| 663 | } |
Dongdong Deng | c1bb9a9 | 2010-09-13 06:58:00 -0500 | [diff] [blame] | 664 | if (arch_kgdb_ops.correct_hw_break) |
| 665 | arch_kgdb_ops.correct_hw_break(); |
Jason Wessel | 4da75b9 | 2010-04-02 11:57:18 -0500 | [diff] [blame] | 666 | if (trace_on) |
| 667 | tracing_on(); |
Jason Wessel | dfee3a7 | 2010-05-21 08:46:00 -0500 | [diff] [blame] | 668 | |
| 669 | kgdb_info[cpu].exception_state &= |
| 670 | ~(DCPU_WANT_MASTER | DCPU_IS_SLAVE); |
| 671 | kgdb_info[cpu].enter_kgdb--; |
Peter Zijlstra | 4e857c5 | 2014-03-17 18:06:10 +0100 | [diff] [blame] | 672 | smp_mb__before_atomic(); |
Jason Wessel | dfee3a7 | 2010-05-21 08:46:00 -0500 | [diff] [blame] | 673 | atomic_dec(&masters_in_kgdb); |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 674 | /* Free kgdb_active */ |
| 675 | atomic_set(&kgdb_active, -1); |
Jason Wessel | dfee3a7 | 2010-05-21 08:46:00 -0500 | [diff] [blame] | 676 | raw_spin_unlock(&dbg_master_lock); |
Jason Wessel | 16cdc62 | 2010-08-06 11:47:14 -0500 | [diff] [blame] | 677 | dbg_touch_watchdogs(); |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 678 | local_irq_restore(flags); |
| 679 | |
Jason Wessel | dcc7871 | 2010-05-20 21:04:21 -0500 | [diff] [blame] | 680 | return kgdb_info[cpu].ret_state; |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 681 | } |
| 682 | |
Jason Wessel | 62fae31 | 2010-04-02 11:47:02 -0500 | [diff] [blame] | 683 | /* |
| 684 | * kgdb_handle_exception() - main entry point from a kernel exception |
| 685 | * |
| 686 | * Locking hierarchy: |
| 687 | * interface locks, if any (begin_session) |
| 688 | * kgdb lock (kgdb_active) |
| 689 | */ |
| 690 | int |
| 691 | kgdb_handle_exception(int evector, int signo, int ecode, struct pt_regs *regs) |
| 692 | { |
| 693 | struct kgdb_state kgdb_var; |
| 694 | struct kgdb_state *ks = &kgdb_var; |
Anton Vorontsov | 5a14fea | 2012-09-24 14:27:50 -0700 | [diff] [blame] | 695 | int ret = 0; |
| 696 | |
| 697 | if (arch_kgdb_ops.enable_nmi) |
| 698 | arch_kgdb_ops.enable_nmi(0); |
Colin Cross | 5516fd7 | 2015-01-28 17:02:14 +0530 | [diff] [blame] | 699 | /* |
| 700 | * Avoid entering the debugger if we were triggered due to an oops |
| 701 | * but panic_timeout indicates the system should automatically |
| 702 | * reboot on panic. We don't want to get stuck waiting for input |
| 703 | * on such systems, especially if its "just" an oops. |
| 704 | */ |
| 705 | if (signo != SIGTRAP && panic_timeout) |
| 706 | return 1; |
Jason Wessel | 62fae31 | 2010-04-02 11:47:02 -0500 | [diff] [blame] | 707 | |
Mike Travis | 8daaa5f | 2013-10-02 10:14:18 -0500 | [diff] [blame] | 708 | memset(ks, 0, sizeof(struct kgdb_state)); |
Jason Wessel | 62fae31 | 2010-04-02 11:47:02 -0500 | [diff] [blame] | 709 | ks->cpu = raw_smp_processor_id(); |
| 710 | ks->ex_vector = evector; |
| 711 | ks->signo = signo; |
Jason Wessel | 62fae31 | 2010-04-02 11:47:02 -0500 | [diff] [blame] | 712 | ks->err_code = ecode; |
Jason Wessel | 62fae31 | 2010-04-02 11:47:02 -0500 | [diff] [blame] | 713 | ks->linux_regs = regs; |
| 714 | |
| 715 | if (kgdb_reenter_check(ks)) |
Anton Vorontsov | 5a14fea | 2012-09-24 14:27:50 -0700 | [diff] [blame] | 716 | goto out; /* Ouch, double exception ! */ |
Jason Wessel | dfee3a7 | 2010-05-21 08:46:00 -0500 | [diff] [blame] | 717 | if (kgdb_info[ks->cpu].enter_kgdb != 0) |
Anton Vorontsov | 5a14fea | 2012-09-24 14:27:50 -0700 | [diff] [blame] | 718 | goto out; |
Jason Wessel | dfee3a7 | 2010-05-21 08:46:00 -0500 | [diff] [blame] | 719 | |
Anton Vorontsov | 5a14fea | 2012-09-24 14:27:50 -0700 | [diff] [blame] | 720 | ret = kgdb_cpu_enter(ks, regs, DCPU_WANT_MASTER); |
| 721 | out: |
| 722 | if (arch_kgdb_ops.enable_nmi) |
| 723 | arch_kgdb_ops.enable_nmi(1); |
| 724 | return ret; |
Jason Wessel | 62fae31 | 2010-04-02 11:47:02 -0500 | [diff] [blame] | 725 | } |
| 726 | |
Jason Wessel | f30fed1 | 2012-10-12 06:37:33 -0500 | [diff] [blame] | 727 | /* |
| 728 | * GDB places a breakpoint at this function to know dynamically |
| 729 | * loaded objects. It's not defined static so that only one instance with this |
| 730 | * name exists in the kernel. |
| 731 | */ |
| 732 | |
| 733 | static int module_event(struct notifier_block *self, unsigned long val, |
| 734 | void *data) |
| 735 | { |
| 736 | return 0; |
| 737 | } |
| 738 | |
| 739 | static struct notifier_block dbg_module_load_nb = { |
| 740 | .notifier_call = module_event, |
| 741 | }; |
| 742 | |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 743 | int kgdb_nmicallback(int cpu, void *regs) |
| 744 | { |
| 745 | #ifdef CONFIG_SMP |
Jason Wessel | 62fae31 | 2010-04-02 11:47:02 -0500 | [diff] [blame] | 746 | struct kgdb_state kgdb_var; |
| 747 | struct kgdb_state *ks = &kgdb_var; |
| 748 | |
| 749 | memset(ks, 0, sizeof(struct kgdb_state)); |
| 750 | ks->cpu = cpu; |
| 751 | ks->linux_regs = regs; |
| 752 | |
Jason Wessel | dfee3a7 | 2010-05-21 08:46:00 -0500 | [diff] [blame] | 753 | if (kgdb_info[ks->cpu].enter_kgdb == 0 && |
| 754 | raw_spin_is_locked(&dbg_master_lock)) { |
| 755 | kgdb_cpu_enter(ks, regs, DCPU_IS_SLAVE); |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 756 | return 0; |
| 757 | } |
| 758 | #endif |
| 759 | return 1; |
| 760 | } |
| 761 | |
Mike Travis | fc8b137 | 2014-01-14 10:25:52 -0600 | [diff] [blame] | 762 | int kgdb_nmicallin(int cpu, int trapnr, void *regs, int err_code, |
| 763 | atomic_t *send_ready) |
Mike Travis | 8daaa5f | 2013-10-02 10:14:18 -0500 | [diff] [blame] | 764 | { |
| 765 | #ifdef CONFIG_SMP |
| 766 | if (!kgdb_io_ready(0) || !send_ready) |
| 767 | return 1; |
| 768 | |
| 769 | if (kgdb_info[cpu].enter_kgdb == 0) { |
| 770 | struct kgdb_state kgdb_var; |
| 771 | struct kgdb_state *ks = &kgdb_var; |
| 772 | |
| 773 | memset(ks, 0, sizeof(struct kgdb_state)); |
| 774 | ks->cpu = cpu; |
| 775 | ks->ex_vector = trapnr; |
| 776 | ks->signo = SIGTRAP; |
Mike Travis | fc8b137 | 2014-01-14 10:25:52 -0600 | [diff] [blame] | 777 | ks->err_code = err_code; |
Mike Travis | 8daaa5f | 2013-10-02 10:14:18 -0500 | [diff] [blame] | 778 | ks->linux_regs = regs; |
| 779 | ks->send_ready = send_ready; |
| 780 | kgdb_cpu_enter(ks, regs, DCPU_WANT_MASTER); |
| 781 | return 0; |
| 782 | } |
| 783 | #endif |
| 784 | return 1; |
| 785 | } |
| 786 | |
Jason Wessel | aabdc3b | 2008-06-24 10:52:55 -0500 | [diff] [blame] | 787 | static void kgdb_console_write(struct console *co, const char *s, |
| 788 | unsigned count) |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 789 | { |
| 790 | unsigned long flags; |
| 791 | |
| 792 | /* If we're debugging, or KGDB has not connected, don't try |
| 793 | * and print. */ |
Jason Wessel | dcc7871 | 2010-05-20 21:04:21 -0500 | [diff] [blame] | 794 | if (!kgdb_connected || atomic_read(&kgdb_active) != -1 || dbg_kdb_mode) |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 795 | return; |
| 796 | |
| 797 | local_irq_save(flags); |
Jason Wessel | 53197fc | 2010-04-02 11:48:03 -0500 | [diff] [blame] | 798 | gdbstub_msg_write(s, count); |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 799 | local_irq_restore(flags); |
| 800 | } |
| 801 | |
| 802 | static struct console kgdbcons = { |
| 803 | .name = "kgdb", |
| 804 | .write = kgdb_console_write, |
| 805 | .flags = CON_PRINTBUFFER | CON_ENABLED, |
| 806 | .index = -1, |
| 807 | }; |
| 808 | |
| 809 | #ifdef CONFIG_MAGIC_SYSRQ |
Dmitry Torokhov | 1495cc9 | 2010-08-17 21:15:46 -0700 | [diff] [blame] | 810 | static void sysrq_handle_dbg(int key) |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 811 | { |
Jason Wessel | 53197fc | 2010-04-02 11:48:03 -0500 | [diff] [blame] | 812 | if (!dbg_io_ops) { |
Fabian Frederick | 0f16996 | 2014-06-12 21:30:11 +0200 | [diff] [blame] | 813 | pr_crit("ERROR: No KGDB I/O module available\n"); |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 814 | return; |
| 815 | } |
Jason Wessel | dcc7871 | 2010-05-20 21:04:21 -0500 | [diff] [blame] | 816 | if (!kgdb_connected) { |
| 817 | #ifdef CONFIG_KGDB_KDB |
| 818 | if (!dbg_kdb_mode) |
Fabian Frederick | 0f16996 | 2014-06-12 21:30:11 +0200 | [diff] [blame] | 819 | pr_crit("KGDB or $3#33 for KDB\n"); |
Jason Wessel | dcc7871 | 2010-05-20 21:04:21 -0500 | [diff] [blame] | 820 | #else |
Fabian Frederick | 0f16996 | 2014-06-12 21:30:11 +0200 | [diff] [blame] | 821 | pr_crit("Entering KGDB\n"); |
Jason Wessel | dcc7871 | 2010-05-20 21:04:21 -0500 | [diff] [blame] | 822 | #endif |
| 823 | } |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 824 | |
| 825 | kgdb_breakpoint(); |
| 826 | } |
| 827 | |
Jason Wessel | 53197fc | 2010-04-02 11:48:03 -0500 | [diff] [blame] | 828 | static struct sysrq_key_op sysrq_dbg_op = { |
| 829 | .handler = sysrq_handle_dbg, |
zhangwei(Jovi) | f345650 | 2013-04-30 15:28:51 -0700 | [diff] [blame] | 830 | .help_msg = "debug(g)", |
Jason Wessel | 364b5b7 | 2009-05-13 21:56:59 -0500 | [diff] [blame] | 831 | .action_msg = "DEBUG", |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 832 | }; |
| 833 | #endif |
| 834 | |
Jason Wessel | 4402c15 | 2010-05-20 21:04:28 -0500 | [diff] [blame] | 835 | static int kgdb_panic_event(struct notifier_block *self, |
| 836 | unsigned long val, |
| 837 | void *data) |
| 838 | { |
Colin Cross | 5516fd7 | 2015-01-28 17:02:14 +0530 | [diff] [blame] | 839 | /* |
| 840 | * Avoid entering the debugger if we were triggered due to a panic |
| 841 | * We don't want to get stuck waiting for input from user in such case. |
| 842 | * panic_timeout indicates the system should automatically |
| 843 | * reboot on panic. |
| 844 | */ |
| 845 | if (panic_timeout) |
| 846 | return NOTIFY_DONE; |
| 847 | |
Jason Wessel | 4402c15 | 2010-05-20 21:04:28 -0500 | [diff] [blame] | 848 | if (dbg_kdb_mode) |
| 849 | kdb_printf("PANIC: %s\n", (char *)data); |
| 850 | kgdb_breakpoint(); |
| 851 | return NOTIFY_DONE; |
| 852 | } |
| 853 | |
| 854 | static struct notifier_block kgdb_panic_event_nb = { |
| 855 | .notifier_call = kgdb_panic_event, |
| 856 | .priority = INT_MAX, |
| 857 | }; |
| 858 | |
Jason Wessel | 0b4b382 | 2010-05-20 21:04:29 -0500 | [diff] [blame] | 859 | void __weak kgdb_arch_late(void) |
| 860 | { |
| 861 | } |
| 862 | |
| 863 | void __init dbg_late_init(void) |
| 864 | { |
| 865 | dbg_is_early = false; |
| 866 | if (kgdb_io_module_registered) |
| 867 | kgdb_arch_late(); |
| 868 | kdb_init(KDB_INIT_FULL); |
| 869 | } |
| 870 | |
Jason Wessel | 2366e04 | 2012-03-16 14:20:41 -0500 | [diff] [blame] | 871 | static int |
| 872 | dbg_notify_reboot(struct notifier_block *this, unsigned long code, void *x) |
| 873 | { |
Jason Wessel | bec4d62 | 2012-03-19 19:35:55 -0500 | [diff] [blame] | 874 | /* |
| 875 | * Take the following action on reboot notify depending on value: |
| 876 | * 1 == Enter debugger |
| 877 | * 0 == [the default] detatch debug client |
| 878 | * -1 == Do nothing... and use this until the board resets |
| 879 | */ |
| 880 | switch (kgdbreboot) { |
| 881 | case 1: |
| 882 | kgdb_breakpoint(); |
| 883 | case -1: |
| 884 | goto done; |
| 885 | } |
Jason Wessel | 2366e04 | 2012-03-16 14:20:41 -0500 | [diff] [blame] | 886 | if (!dbg_kdb_mode) |
| 887 | gdbstub_exit(code); |
Jason Wessel | bec4d62 | 2012-03-19 19:35:55 -0500 | [diff] [blame] | 888 | done: |
Jason Wessel | 2366e04 | 2012-03-16 14:20:41 -0500 | [diff] [blame] | 889 | return NOTIFY_DONE; |
| 890 | } |
| 891 | |
| 892 | static struct notifier_block dbg_reboot_notifier = { |
| 893 | .notifier_call = dbg_notify_reboot, |
| 894 | .next = NULL, |
| 895 | .priority = INT_MAX, |
| 896 | }; |
| 897 | |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 898 | static void kgdb_register_callbacks(void) |
| 899 | { |
| 900 | if (!kgdb_io_module_registered) { |
| 901 | kgdb_io_module_registered = 1; |
| 902 | kgdb_arch_init(); |
Jason Wessel | 0b4b382 | 2010-05-20 21:04:29 -0500 | [diff] [blame] | 903 | if (!dbg_is_early) |
| 904 | kgdb_arch_late(); |
Jason Wessel | f30fed1 | 2012-10-12 06:37:33 -0500 | [diff] [blame] | 905 | register_module_notifier(&dbg_module_load_nb); |
Jason Wessel | 2366e04 | 2012-03-16 14:20:41 -0500 | [diff] [blame] | 906 | register_reboot_notifier(&dbg_reboot_notifier); |
Jason Wessel | 4402c15 | 2010-05-20 21:04:28 -0500 | [diff] [blame] | 907 | atomic_notifier_chain_register(&panic_notifier_list, |
| 908 | &kgdb_panic_event_nb); |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 909 | #ifdef CONFIG_MAGIC_SYSRQ |
Jason Wessel | 53197fc | 2010-04-02 11:48:03 -0500 | [diff] [blame] | 910 | register_sysrq_key('g', &sysrq_dbg_op); |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 911 | #endif |
| 912 | if (kgdb_use_con && !kgdb_con_registered) { |
| 913 | register_console(&kgdbcons); |
| 914 | kgdb_con_registered = 1; |
| 915 | } |
| 916 | } |
| 917 | } |
| 918 | |
| 919 | static void kgdb_unregister_callbacks(void) |
| 920 | { |
| 921 | /* |
| 922 | * When this routine is called KGDB should unregister from the |
| 923 | * panic handler and clean up, making sure it is not handling any |
| 924 | * break exceptions at the time. |
| 925 | */ |
| 926 | if (kgdb_io_module_registered) { |
| 927 | kgdb_io_module_registered = 0; |
Jason Wessel | 2366e04 | 2012-03-16 14:20:41 -0500 | [diff] [blame] | 928 | unregister_reboot_notifier(&dbg_reboot_notifier); |
Jason Wessel | f30fed1 | 2012-10-12 06:37:33 -0500 | [diff] [blame] | 929 | unregister_module_notifier(&dbg_module_load_nb); |
Jason Wessel | 4402c15 | 2010-05-20 21:04:28 -0500 | [diff] [blame] | 930 | atomic_notifier_chain_unregister(&panic_notifier_list, |
| 931 | &kgdb_panic_event_nb); |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 932 | kgdb_arch_exit(); |
| 933 | #ifdef CONFIG_MAGIC_SYSRQ |
Jason Wessel | 53197fc | 2010-04-02 11:48:03 -0500 | [diff] [blame] | 934 | unregister_sysrq_key('g', &sysrq_dbg_op); |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 935 | #endif |
| 936 | if (kgdb_con_registered) { |
| 937 | unregister_console(&kgdbcons); |
| 938 | kgdb_con_registered = 0; |
| 939 | } |
| 940 | } |
| 941 | } |
| 942 | |
Jason Wessel | 1cee5e3 | 2009-06-03 14:06:57 -0500 | [diff] [blame] | 943 | /* |
| 944 | * There are times a tasklet needs to be used vs a compiled in |
| 945 | * break point so as to cause an exception outside a kgdb I/O module, |
| 946 | * such as is the case with kgdboe, where calling a breakpoint in the |
| 947 | * I/O driver itself would be fatal. |
| 948 | */ |
| 949 | static void kgdb_tasklet_bpt(unsigned long ing) |
| 950 | { |
| 951 | kgdb_breakpoint(); |
| 952 | atomic_set(&kgdb_break_tasklet_var, 0); |
| 953 | } |
| 954 | |
| 955 | static DECLARE_TASKLET(kgdb_tasklet_breakpoint, kgdb_tasklet_bpt, 0); |
| 956 | |
| 957 | void kgdb_schedule_breakpoint(void) |
| 958 | { |
| 959 | if (atomic_read(&kgdb_break_tasklet_var) || |
| 960 | atomic_read(&kgdb_active) != -1 || |
| 961 | atomic_read(&kgdb_setting_breakpoint)) |
| 962 | return; |
| 963 | atomic_inc(&kgdb_break_tasklet_var); |
| 964 | tasklet_schedule(&kgdb_tasklet_breakpoint); |
| 965 | } |
| 966 | EXPORT_SYMBOL_GPL(kgdb_schedule_breakpoint); |
| 967 | |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 968 | static void kgdb_initial_breakpoint(void) |
| 969 | { |
| 970 | kgdb_break_asap = 0; |
| 971 | |
Fabian Frederick | 0f16996 | 2014-06-12 21:30:11 +0200 | [diff] [blame] | 972 | pr_crit("Waiting for connection from remote gdb...\n"); |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 973 | kgdb_breakpoint(); |
| 974 | } |
| 975 | |
| 976 | /** |
Jason Wessel | 737a460 | 2008-03-07 16:34:16 -0600 | [diff] [blame] | 977 | * kgdb_register_io_module - register KGDB IO module |
Jason Wessel | 53197fc | 2010-04-02 11:48:03 -0500 | [diff] [blame] | 978 | * @new_dbg_io_ops: the io ops vector |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 979 | * |
| 980 | * Register it with the KGDB core. |
| 981 | */ |
Jason Wessel | 53197fc | 2010-04-02 11:48:03 -0500 | [diff] [blame] | 982 | int kgdb_register_io_module(struct kgdb_io *new_dbg_io_ops) |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 983 | { |
| 984 | int err; |
| 985 | |
| 986 | spin_lock(&kgdb_registration_lock); |
| 987 | |
Jason Wessel | 53197fc | 2010-04-02 11:48:03 -0500 | [diff] [blame] | 988 | if (dbg_io_ops) { |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 989 | spin_unlock(&kgdb_registration_lock); |
| 990 | |
Fabian Frederick | 0f16996 | 2014-06-12 21:30:11 +0200 | [diff] [blame] | 991 | pr_err("Another I/O driver is already registered with KGDB\n"); |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 992 | return -EBUSY; |
| 993 | } |
| 994 | |
Jason Wessel | 53197fc | 2010-04-02 11:48:03 -0500 | [diff] [blame] | 995 | if (new_dbg_io_ops->init) { |
| 996 | err = new_dbg_io_ops->init(); |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 997 | if (err) { |
| 998 | spin_unlock(&kgdb_registration_lock); |
| 999 | return err; |
| 1000 | } |
| 1001 | } |
| 1002 | |
Jason Wessel | 53197fc | 2010-04-02 11:48:03 -0500 | [diff] [blame] | 1003 | dbg_io_ops = new_dbg_io_ops; |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 1004 | |
| 1005 | spin_unlock(&kgdb_registration_lock); |
| 1006 | |
Fabian Frederick | 0f16996 | 2014-06-12 21:30:11 +0200 | [diff] [blame] | 1007 | pr_info("Registered I/O driver %s\n", new_dbg_io_ops->name); |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 1008 | |
| 1009 | /* Arm KGDB now. */ |
| 1010 | kgdb_register_callbacks(); |
| 1011 | |
| 1012 | if (kgdb_break_asap) |
| 1013 | kgdb_initial_breakpoint(); |
| 1014 | |
| 1015 | return 0; |
| 1016 | } |
| 1017 | EXPORT_SYMBOL_GPL(kgdb_register_io_module); |
| 1018 | |
| 1019 | /** |
| 1020 | * kkgdb_unregister_io_module - unregister KGDB IO module |
Jason Wessel | 53197fc | 2010-04-02 11:48:03 -0500 | [diff] [blame] | 1021 | * @old_dbg_io_ops: the io ops vector |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 1022 | * |
| 1023 | * Unregister it with the KGDB core. |
| 1024 | */ |
Jason Wessel | 53197fc | 2010-04-02 11:48:03 -0500 | [diff] [blame] | 1025 | void kgdb_unregister_io_module(struct kgdb_io *old_dbg_io_ops) |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 1026 | { |
| 1027 | BUG_ON(kgdb_connected); |
| 1028 | |
| 1029 | /* |
| 1030 | * KGDB is no longer able to communicate out, so |
| 1031 | * unregister our callbacks and reset state. |
| 1032 | */ |
| 1033 | kgdb_unregister_callbacks(); |
| 1034 | |
| 1035 | spin_lock(&kgdb_registration_lock); |
| 1036 | |
Jason Wessel | 53197fc | 2010-04-02 11:48:03 -0500 | [diff] [blame] | 1037 | WARN_ON_ONCE(dbg_io_ops != old_dbg_io_ops); |
| 1038 | dbg_io_ops = NULL; |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 1039 | |
| 1040 | spin_unlock(&kgdb_registration_lock); |
| 1041 | |
Fabian Frederick | 0f16996 | 2014-06-12 21:30:11 +0200 | [diff] [blame] | 1042 | pr_info("Unregistered I/O driver %s, debugger disabled\n", |
Jason Wessel | 53197fc | 2010-04-02 11:48:03 -0500 | [diff] [blame] | 1043 | old_dbg_io_ops->name); |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 1044 | } |
| 1045 | EXPORT_SYMBOL_GPL(kgdb_unregister_io_module); |
| 1046 | |
Jason Wessel | dcc7871 | 2010-05-20 21:04:21 -0500 | [diff] [blame] | 1047 | int dbg_io_get_char(void) |
| 1048 | { |
| 1049 | int ret = dbg_io_ops->read_char(); |
Jason Wessel | f5316b4 | 2010-05-20 21:04:22 -0500 | [diff] [blame] | 1050 | if (ret == NO_POLL_CHAR) |
| 1051 | return -1; |
Jason Wessel | dcc7871 | 2010-05-20 21:04:21 -0500 | [diff] [blame] | 1052 | if (!dbg_kdb_mode) |
| 1053 | return ret; |
| 1054 | if (ret == 127) |
| 1055 | return 8; |
| 1056 | return ret; |
| 1057 | } |
| 1058 | |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 1059 | /** |
| 1060 | * kgdb_breakpoint - generate breakpoint exception |
| 1061 | * |
| 1062 | * This function will generate a breakpoint exception. It is used at the |
| 1063 | * beginning of a program to sync up with a debugger and can be used |
| 1064 | * otherwise as a quick means to stop program execution and "break" into |
| 1065 | * the debugger. |
| 1066 | */ |
Vijaya Kumar K | d498d4b | 2014-01-28 16:50:20 +0530 | [diff] [blame] | 1067 | noinline void kgdb_breakpoint(void) |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 1068 | { |
Jason Wessel | ae6bf53 | 2010-04-02 14:58:18 -0500 | [diff] [blame] | 1069 | atomic_inc(&kgdb_setting_breakpoint); |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 1070 | wmb(); /* Sync point before breakpoint */ |
| 1071 | arch_kgdb_breakpoint(); |
| 1072 | wmb(); /* Sync point after breakpoint */ |
Jason Wessel | ae6bf53 | 2010-04-02 14:58:18 -0500 | [diff] [blame] | 1073 | atomic_dec(&kgdb_setting_breakpoint); |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 1074 | } |
| 1075 | EXPORT_SYMBOL_GPL(kgdb_breakpoint); |
| 1076 | |
| 1077 | static int __init opt_kgdb_wait(char *str) |
| 1078 | { |
| 1079 | kgdb_break_asap = 1; |
| 1080 | |
Jason Wessel | dcc7871 | 2010-05-20 21:04:21 -0500 | [diff] [blame] | 1081 | kdb_init(KDB_INIT_EARLY); |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 1082 | if (kgdb_io_module_registered) |
| 1083 | kgdb_initial_breakpoint(); |
| 1084 | |
| 1085 | return 0; |
| 1086 | } |
| 1087 | |
| 1088 | early_param("kgdbwait", opt_kgdb_wait); |