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 | */ |
| 30 | #include <linux/pid_namespace.h> |
Jason Wessel | 7c3078b | 2008-02-15 14:55:54 -0600 | [diff] [blame] | 31 | #include <linux/clocksource.h> |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 32 | #include <linux/interrupt.h> |
| 33 | #include <linux/spinlock.h> |
| 34 | #include <linux/console.h> |
| 35 | #include <linux/threads.h> |
| 36 | #include <linux/uaccess.h> |
| 37 | #include <linux/kernel.h> |
| 38 | #include <linux/module.h> |
| 39 | #include <linux/ptrace.h> |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 40 | #include <linux/string.h> |
| 41 | #include <linux/delay.h> |
| 42 | #include <linux/sched.h> |
| 43 | #include <linux/sysrq.h> |
| 44 | #include <linux/init.h> |
| 45 | #include <linux/kgdb.h> |
Jason Wessel | dcc7871 | 2010-05-20 21:04:21 -0500 | [diff] [blame] | 46 | #include <linux/kdb.h> |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 47 | #include <linux/pid.h> |
| 48 | #include <linux/smp.h> |
| 49 | #include <linux/mm.h> |
Jason Wessel | fb70b58 | 2010-08-13 12:44:04 -0500 | [diff] [blame] | 50 | #include <linux/rcupdate.h> |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 51 | |
| 52 | #include <asm/cacheflush.h> |
| 53 | #include <asm/byteorder.h> |
| 54 | #include <asm/atomic.h> |
| 55 | #include <asm/system.h> |
Jason Wessel | 53197fc | 2010-04-02 11:48:03 -0500 | [diff] [blame] | 56 | |
| 57 | #include "debug_core.h" |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 58 | |
| 59 | static int kgdb_break_asap; |
| 60 | |
Jason Wessel | 53197fc | 2010-04-02 11:48:03 -0500 | [diff] [blame] | 61 | struct debuggerinfo_struct kgdb_info[NR_CPUS]; |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 62 | |
| 63 | /** |
| 64 | * kgdb_connected - Is a host GDB connected to us? |
| 65 | */ |
| 66 | int kgdb_connected; |
| 67 | EXPORT_SYMBOL_GPL(kgdb_connected); |
| 68 | |
| 69 | /* All the KGDB handlers are installed */ |
Jason Wessel | f503b5a | 2010-05-20 21:04:25 -0500 | [diff] [blame] | 70 | int kgdb_io_module_registered; |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 71 | |
| 72 | /* Guard for recursive entry */ |
| 73 | static int exception_level; |
| 74 | |
Jason Wessel | 53197fc | 2010-04-02 11:48:03 -0500 | [diff] [blame] | 75 | struct kgdb_io *dbg_io_ops; |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 76 | static DEFINE_SPINLOCK(kgdb_registration_lock); |
| 77 | |
| 78 | /* kgdb console driver is loaded */ |
| 79 | static int kgdb_con_registered; |
| 80 | /* determine if kgdb console output should be used */ |
| 81 | static int kgdb_use_con; |
Jason Wessel | 0b4b382 | 2010-05-20 21:04:29 -0500 | [diff] [blame] | 82 | /* Flag for alternate operations for early debugging */ |
| 83 | bool dbg_is_early = true; |
Jason Wessel | dcc7871 | 2010-05-20 21:04:21 -0500 | [diff] [blame] | 84 | /* Next cpu to become the master debug core */ |
| 85 | int dbg_switch_cpu; |
| 86 | |
| 87 | /* Use kdb or gdbserver mode */ |
Jason Wessel | a0de055 | 2010-05-20 21:04:24 -0500 | [diff] [blame] | 88 | int dbg_kdb_mode = 1; |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 89 | |
| 90 | static int __init opt_kgdb_con(char *str) |
| 91 | { |
| 92 | kgdb_use_con = 1; |
| 93 | return 0; |
| 94 | } |
| 95 | |
| 96 | early_param("kgdbcon", opt_kgdb_con); |
| 97 | |
| 98 | module_param(kgdb_use_con, int, 0644); |
| 99 | |
| 100 | /* |
| 101 | * Holds information about breakpoints in a kernel. These breakpoints are |
| 102 | * added and removed by gdb. |
| 103 | */ |
| 104 | static struct kgdb_bkpt kgdb_break[KGDB_MAX_BREAKPOINTS] = { |
| 105 | [0 ... KGDB_MAX_BREAKPOINTS-1] = { .state = BP_UNDEFINED } |
| 106 | }; |
| 107 | |
| 108 | /* |
| 109 | * The CPU# of the active CPU, or -1 if none: |
| 110 | */ |
| 111 | atomic_t kgdb_active = ATOMIC_INIT(-1); |
Jason Wessel | dcc7871 | 2010-05-20 21:04:21 -0500 | [diff] [blame] | 112 | EXPORT_SYMBOL_GPL(kgdb_active); |
Jason Wessel | dfee3a7 | 2010-05-21 08:46:00 -0500 | [diff] [blame] | 113 | static DEFINE_RAW_SPINLOCK(dbg_master_lock); |
| 114 | static DEFINE_RAW_SPINLOCK(dbg_slave_lock); |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 115 | |
| 116 | /* |
| 117 | * We use NR_CPUs not PERCPU, in case kgdb is used to debug early |
| 118 | * bootup code (which might not have percpu set up yet): |
| 119 | */ |
Jason Wessel | dfee3a7 | 2010-05-21 08:46:00 -0500 | [diff] [blame] | 120 | static atomic_t masters_in_kgdb; |
| 121 | static atomic_t slaves_in_kgdb; |
Jason Wessel | 1cee5e3 | 2009-06-03 14:06:57 -0500 | [diff] [blame] | 122 | static atomic_t kgdb_break_tasklet_var; |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 123 | atomic_t kgdb_setting_breakpoint; |
| 124 | |
| 125 | struct task_struct *kgdb_usethread; |
| 126 | struct task_struct *kgdb_contthread; |
| 127 | |
| 128 | int kgdb_single_step; |
Jason Wessel | 53197fc | 2010-04-02 11:48:03 -0500 | [diff] [blame] | 129 | static pid_t kgdb_sstep_pid; |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 130 | |
| 131 | /* to keep track of the CPU which is doing the single stepping*/ |
| 132 | atomic_t kgdb_cpu_doing_single_step = ATOMIC_INIT(-1); |
| 133 | |
| 134 | /* |
| 135 | * If you are debugging a problem where roundup (the collection of |
| 136 | * all other CPUs) is a problem [this should be extremely rare], |
| 137 | * then use the nokgdbroundup option to avoid roundup. In that case |
| 138 | * the other CPUs might interfere with your debugging context, so |
| 139 | * use this with care: |
| 140 | */ |
Harvey Harrison | 688b744 | 2008-04-24 16:57:23 -0500 | [diff] [blame] | 141 | static int kgdb_do_roundup = 1; |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 142 | |
| 143 | static int __init opt_nokgdbroundup(char *str) |
| 144 | { |
| 145 | kgdb_do_roundup = 0; |
| 146 | |
| 147 | return 0; |
| 148 | } |
| 149 | |
| 150 | early_param("nokgdbroundup", opt_nokgdbroundup); |
| 151 | |
| 152 | /* |
| 153 | * Finally, some KGDB code :-) |
| 154 | */ |
| 155 | |
| 156 | /* |
| 157 | * Weak aliases for breakpoint management, |
| 158 | * can be overriden by architectures when needed: |
| 159 | */ |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 160 | int __weak kgdb_arch_set_breakpoint(unsigned long addr, char *saved_instr) |
| 161 | { |
| 162 | int err; |
| 163 | |
| 164 | err = probe_kernel_read(saved_instr, (char *)addr, BREAK_INSTR_SIZE); |
| 165 | if (err) |
| 166 | return err; |
| 167 | |
| 168 | return probe_kernel_write((char *)addr, arch_kgdb_ops.gdb_bpt_instr, |
| 169 | BREAK_INSTR_SIZE); |
| 170 | } |
| 171 | |
| 172 | int __weak kgdb_arch_remove_breakpoint(unsigned long addr, char *bundle) |
| 173 | { |
| 174 | return probe_kernel_write((char *)addr, |
| 175 | (char *)bundle, BREAK_INSTR_SIZE); |
| 176 | } |
| 177 | |
Jason Wessel | a9b60bf | 2008-08-01 08:39:34 -0500 | [diff] [blame] | 178 | int __weak kgdb_validate_break_address(unsigned long addr) |
| 179 | { |
| 180 | char tmp_variable[BREAK_INSTR_SIZE]; |
| 181 | int err; |
| 182 | /* Validate setting the breakpoint and then removing it. In the |
| 183 | * remove fails, the kernel needs to emit a bad message because we |
| 184 | * are deep trouble not being able to put things back the way we |
| 185 | * found them. |
| 186 | */ |
| 187 | err = kgdb_arch_set_breakpoint(addr, tmp_variable); |
| 188 | if (err) |
| 189 | return err; |
| 190 | err = kgdb_arch_remove_breakpoint(addr, tmp_variable); |
| 191 | if (err) |
| 192 | printk(KERN_ERR "KGDB: Critical breakpoint error, kernel " |
| 193 | "memory destroyed at: %lx", addr); |
| 194 | return err; |
| 195 | } |
| 196 | |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 197 | unsigned long __weak kgdb_arch_pc(int exception, struct pt_regs *regs) |
| 198 | { |
| 199 | return instruction_pointer(regs); |
| 200 | } |
| 201 | |
| 202 | int __weak kgdb_arch_init(void) |
| 203 | { |
| 204 | return 0; |
| 205 | } |
| 206 | |
Jason Wessel | b4b8ac5 | 2008-02-20 13:33:38 -0600 | [diff] [blame] | 207 | int __weak kgdb_skipexception(int exception, struct pt_regs *regs) |
| 208 | { |
| 209 | return 0; |
| 210 | } |
| 211 | |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 212 | /* |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 213 | * Some architectures need cache flushes when we set/clear a |
| 214 | * breakpoint: |
| 215 | */ |
| 216 | static void kgdb_flush_swbreak_addr(unsigned long addr) |
| 217 | { |
| 218 | if (!CACHE_FLUSH_IS_SAFE) |
| 219 | return; |
| 220 | |
Jason Wessel | 737a460 | 2008-03-07 16:34:16 -0600 | [diff] [blame] | 221 | if (current->mm && current->mm->mmap_cache) { |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 222 | flush_cache_range(current->mm->mmap_cache, |
| 223 | addr, addr + BREAK_INSTR_SIZE); |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 224 | } |
Jason Wessel | 1a9a3e7 | 2008-04-01 16:55:28 -0500 | [diff] [blame] | 225 | /* Force flush instruction cache if it was outside the mm */ |
| 226 | flush_icache_range(addr, addr + BREAK_INSTR_SIZE); |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 227 | } |
| 228 | |
| 229 | /* |
| 230 | * SW breakpoint management: |
| 231 | */ |
Jason Wessel | 53197fc | 2010-04-02 11:48:03 -0500 | [diff] [blame] | 232 | int dbg_activate_sw_breakpoints(void) |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 233 | { |
| 234 | unsigned long addr; |
Jason Wessel | 7f8b7ed | 2009-12-11 08:43:20 -0600 | [diff] [blame] | 235 | int error; |
| 236 | int ret = 0; |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 237 | int i; |
| 238 | |
| 239 | for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { |
| 240 | if (kgdb_break[i].state != BP_SET) |
| 241 | continue; |
| 242 | |
| 243 | addr = kgdb_break[i].bpt_addr; |
| 244 | error = kgdb_arch_set_breakpoint(addr, |
| 245 | kgdb_break[i].saved_instr); |
Jason Wessel | 7f8b7ed | 2009-12-11 08:43:20 -0600 | [diff] [blame] | 246 | if (error) { |
| 247 | ret = error; |
| 248 | printk(KERN_INFO "KGDB: BP install failed: %lx", addr); |
| 249 | continue; |
| 250 | } |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 251 | |
| 252 | kgdb_flush_swbreak_addr(addr); |
| 253 | kgdb_break[i].state = BP_ACTIVE; |
| 254 | } |
Jason Wessel | 7f8b7ed | 2009-12-11 08:43:20 -0600 | [diff] [blame] | 255 | return ret; |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 256 | } |
| 257 | |
Jason Wessel | 53197fc | 2010-04-02 11:48:03 -0500 | [diff] [blame] | 258 | int dbg_set_sw_break(unsigned long addr) |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 259 | { |
| 260 | int err = kgdb_validate_break_address(addr); |
| 261 | int breakno = -1; |
| 262 | int i; |
| 263 | |
| 264 | if (err) |
| 265 | return err; |
| 266 | |
| 267 | for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { |
| 268 | if ((kgdb_break[i].state == BP_SET) && |
| 269 | (kgdb_break[i].bpt_addr == addr)) |
| 270 | return -EEXIST; |
| 271 | } |
| 272 | for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { |
| 273 | if (kgdb_break[i].state == BP_REMOVED && |
| 274 | kgdb_break[i].bpt_addr == addr) { |
| 275 | breakno = i; |
| 276 | break; |
| 277 | } |
| 278 | } |
| 279 | |
| 280 | if (breakno == -1) { |
| 281 | for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { |
| 282 | if (kgdb_break[i].state == BP_UNDEFINED) { |
| 283 | breakno = i; |
| 284 | break; |
| 285 | } |
| 286 | } |
| 287 | } |
| 288 | |
| 289 | if (breakno == -1) |
| 290 | return -E2BIG; |
| 291 | |
| 292 | kgdb_break[breakno].state = BP_SET; |
| 293 | kgdb_break[breakno].type = BP_BREAKPOINT; |
| 294 | kgdb_break[breakno].bpt_addr = addr; |
| 295 | |
| 296 | return 0; |
| 297 | } |
| 298 | |
Jason Wessel | dcc7871 | 2010-05-20 21:04:21 -0500 | [diff] [blame] | 299 | int dbg_deactivate_sw_breakpoints(void) |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 300 | { |
| 301 | unsigned long addr; |
Jason Wessel | 7f8b7ed | 2009-12-11 08:43:20 -0600 | [diff] [blame] | 302 | int error; |
| 303 | int ret = 0; |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 304 | int i; |
| 305 | |
| 306 | for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { |
| 307 | if (kgdb_break[i].state != BP_ACTIVE) |
| 308 | continue; |
| 309 | addr = kgdb_break[i].bpt_addr; |
| 310 | error = kgdb_arch_remove_breakpoint(addr, |
| 311 | kgdb_break[i].saved_instr); |
Jason Wessel | 7f8b7ed | 2009-12-11 08:43:20 -0600 | [diff] [blame] | 312 | if (error) { |
| 313 | printk(KERN_INFO "KGDB: BP remove failed: %lx\n", addr); |
| 314 | ret = error; |
| 315 | } |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 316 | |
| 317 | kgdb_flush_swbreak_addr(addr); |
| 318 | kgdb_break[i].state = BP_SET; |
| 319 | } |
Jason Wessel | 7f8b7ed | 2009-12-11 08:43:20 -0600 | [diff] [blame] | 320 | return ret; |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 321 | } |
| 322 | |
Jason Wessel | 53197fc | 2010-04-02 11:48:03 -0500 | [diff] [blame] | 323 | int dbg_remove_sw_break(unsigned long addr) |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 324 | { |
| 325 | int i; |
| 326 | |
| 327 | for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { |
| 328 | if ((kgdb_break[i].state == BP_SET) && |
| 329 | (kgdb_break[i].bpt_addr == addr)) { |
| 330 | kgdb_break[i].state = BP_REMOVED; |
| 331 | return 0; |
| 332 | } |
| 333 | } |
| 334 | return -ENOENT; |
| 335 | } |
| 336 | |
| 337 | int kgdb_isremovedbreak(unsigned long addr) |
| 338 | { |
| 339 | int i; |
| 340 | |
| 341 | for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { |
| 342 | if ((kgdb_break[i].state == BP_REMOVED) && |
| 343 | (kgdb_break[i].bpt_addr == addr)) |
| 344 | return 1; |
| 345 | } |
| 346 | return 0; |
| 347 | } |
| 348 | |
Jason Wessel | 53197fc | 2010-04-02 11:48:03 -0500 | [diff] [blame] | 349 | int dbg_remove_all_break(void) |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 350 | { |
| 351 | unsigned long addr; |
| 352 | int error; |
| 353 | int i; |
| 354 | |
| 355 | /* Clear memory breakpoints. */ |
| 356 | for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { |
Jason Wessel | 737a460 | 2008-03-07 16:34:16 -0600 | [diff] [blame] | 357 | if (kgdb_break[i].state != BP_ACTIVE) |
| 358 | goto setundefined; |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 359 | addr = kgdb_break[i].bpt_addr; |
| 360 | error = kgdb_arch_remove_breakpoint(addr, |
| 361 | kgdb_break[i].saved_instr); |
| 362 | if (error) |
Jason Wessel | 737a460 | 2008-03-07 16:34:16 -0600 | [diff] [blame] | 363 | printk(KERN_ERR "KGDB: breakpoint remove failed: %lx\n", |
| 364 | addr); |
| 365 | setundefined: |
| 366 | kgdb_break[i].state = BP_UNDEFINED; |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 367 | } |
| 368 | |
| 369 | /* Clear hardware breakpoints. */ |
| 370 | if (arch_kgdb_ops.remove_all_hw_break) |
| 371 | arch_kgdb_ops.remove_all_hw_break(); |
| 372 | |
| 373 | return 0; |
| 374 | } |
| 375 | |
| 376 | /* |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 377 | * Return true if there is a valid kgdb I/O module. Also if no |
| 378 | * debugger is attached a message can be printed to the console about |
| 379 | * waiting for the debugger to attach. |
| 380 | * |
| 381 | * The print_wait argument is only to be true when called from inside |
| 382 | * the core kgdb_handle_exception, because it will wait for the |
| 383 | * debugger to attach. |
| 384 | */ |
| 385 | static int kgdb_io_ready(int print_wait) |
| 386 | { |
Jason Wessel | 53197fc | 2010-04-02 11:48:03 -0500 | [diff] [blame] | 387 | if (!dbg_io_ops) |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 388 | return 0; |
| 389 | if (kgdb_connected) |
| 390 | return 1; |
| 391 | if (atomic_read(&kgdb_setting_breakpoint)) |
| 392 | return 1; |
Jason Wessel | dcc7871 | 2010-05-20 21:04:21 -0500 | [diff] [blame] | 393 | if (print_wait) { |
| 394 | #ifdef CONFIG_KGDB_KDB |
| 395 | if (!dbg_kdb_mode) |
| 396 | printk(KERN_CRIT "KGDB: waiting... or $3#33 for KDB\n"); |
| 397 | #else |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 398 | printk(KERN_CRIT "KGDB: Waiting for remote debugger\n"); |
Jason Wessel | dcc7871 | 2010-05-20 21:04:21 -0500 | [diff] [blame] | 399 | #endif |
| 400 | } |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 401 | return 1; |
| 402 | } |
| 403 | |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 404 | static int kgdb_reenter_check(struct kgdb_state *ks) |
| 405 | { |
| 406 | unsigned long addr; |
| 407 | |
| 408 | if (atomic_read(&kgdb_active) != raw_smp_processor_id()) |
| 409 | return 0; |
| 410 | |
| 411 | /* Panic on recursive debugger calls: */ |
| 412 | exception_level++; |
| 413 | addr = kgdb_arch_pc(ks->ex_vector, ks->linux_regs); |
Jason Wessel | dcc7871 | 2010-05-20 21:04:21 -0500 | [diff] [blame] | 414 | dbg_deactivate_sw_breakpoints(); |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 415 | |
| 416 | /* |
| 417 | * If the break point removed ok at the place exception |
| 418 | * occurred, try to recover and print a warning to the end |
| 419 | * user because the user planted a breakpoint in a place that |
| 420 | * KGDB needs in order to function. |
| 421 | */ |
Jason Wessel | 53197fc | 2010-04-02 11:48:03 -0500 | [diff] [blame] | 422 | if (dbg_remove_sw_break(addr) == 0) { |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 423 | exception_level = 0; |
| 424 | kgdb_skipexception(ks->ex_vector, ks->linux_regs); |
Jason Wessel | 53197fc | 2010-04-02 11:48:03 -0500 | [diff] [blame] | 425 | dbg_activate_sw_breakpoints(); |
Jason Wessel | 67baf94 | 2008-02-15 14:55:55 -0600 | [diff] [blame] | 426 | printk(KERN_CRIT "KGDB: re-enter error: breakpoint removed %lx\n", |
| 427 | addr); |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 428 | WARN_ON_ONCE(1); |
| 429 | |
| 430 | return 1; |
| 431 | } |
Jason Wessel | 53197fc | 2010-04-02 11:48:03 -0500 | [diff] [blame] | 432 | dbg_remove_all_break(); |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 433 | kgdb_skipexception(ks->ex_vector, ks->linux_regs); |
| 434 | |
| 435 | if (exception_level > 1) { |
| 436 | dump_stack(); |
| 437 | panic("Recursive entry to debugger"); |
| 438 | } |
| 439 | |
| 440 | printk(KERN_CRIT "KGDB: re-enter exception: ALL breakpoints killed\n"); |
Jason Wessel | 6d90634 | 2010-05-20 21:04:27 -0500 | [diff] [blame] | 441 | #ifdef CONFIG_KGDB_KDB |
| 442 | /* Allow kdb to debug itself one level */ |
| 443 | return 0; |
| 444 | #endif |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 445 | dump_stack(); |
| 446 | panic("Recursive entry to debugger"); |
| 447 | |
| 448 | return 1; |
| 449 | } |
| 450 | |
Jason Wessel | 16cdc62 | 2010-08-06 11:47:14 -0500 | [diff] [blame] | 451 | static void dbg_touch_watchdogs(void) |
| 452 | { |
| 453 | touch_softlockup_watchdog_sync(); |
| 454 | clocksource_touch_watchdog(); |
Jason Wessel | fb70b58 | 2010-08-13 12:44:04 -0500 | [diff] [blame] | 455 | rcu_cpu_stall_reset(); |
Jason Wessel | 16cdc62 | 2010-08-06 11:47:14 -0500 | [diff] [blame] | 456 | } |
| 457 | |
Jason Wessel | dfee3a7 | 2010-05-21 08:46:00 -0500 | [diff] [blame] | 458 | static int kgdb_cpu_enter(struct kgdb_state *ks, struct pt_regs *regs, |
| 459 | int exception_state) |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 460 | { |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 461 | unsigned long flags; |
Jason Wessel | 028e7b1 | 2009-12-11 08:43:17 -0600 | [diff] [blame] | 462 | int sstep_tries = 100; |
Jason Wessel | dcc7871 | 2010-05-20 21:04:21 -0500 | [diff] [blame] | 463 | int error; |
Jason Wessel | dfee3a7 | 2010-05-21 08:46:00 -0500 | [diff] [blame] | 464 | int cpu; |
Jason Wessel | 4da75b9 | 2010-04-02 11:57:18 -0500 | [diff] [blame] | 465 | int trace_on = 0; |
Jason Wessel | dfee3a7 | 2010-05-21 08:46:00 -0500 | [diff] [blame] | 466 | int online_cpus = num_online_cpus(); |
Dongdong Deng | c1bb9a9 | 2010-09-13 06:58:00 -0500 | [diff] [blame] | 467 | |
Jason Wessel | dfee3a7 | 2010-05-21 08:46:00 -0500 | [diff] [blame] | 468 | kgdb_info[ks->cpu].enter_kgdb++; |
| 469 | kgdb_info[ks->cpu].exception_state |= exception_state; |
| 470 | |
| 471 | if (exception_state == DCPU_WANT_MASTER) |
| 472 | atomic_inc(&masters_in_kgdb); |
| 473 | else |
| 474 | atomic_inc(&slaves_in_kgdb); |
Dongdong Deng | d7ba979d | 2010-08-18 06:02:00 -0500 | [diff] [blame] | 475 | |
| 476 | if (arch_kgdb_ops.disable_hw_break) |
| 477 | arch_kgdb_ops.disable_hw_break(regs); |
Dongdong Deng | c1bb9a9 | 2010-09-13 06:58:00 -0500 | [diff] [blame] | 478 | |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 479 | acquirelock: |
| 480 | /* |
| 481 | * Interrupts will be restored by the 'trap return' code, except when |
| 482 | * single stepping. |
| 483 | */ |
| 484 | local_irq_save(flags); |
| 485 | |
Jason Wessel | 62fae31 | 2010-04-02 11:47:02 -0500 | [diff] [blame] | 486 | cpu = ks->cpu; |
| 487 | kgdb_info[cpu].debuggerinfo = regs; |
| 488 | kgdb_info[cpu].task = current; |
Jason Wessel | dcc7871 | 2010-05-20 21:04:21 -0500 | [diff] [blame] | 489 | kgdb_info[cpu].ret_state = 0; |
| 490 | kgdb_info[cpu].irq_depth = hardirq_count() >> HARDIRQ_SHIFT; |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 491 | |
Jason Wessel | dfee3a7 | 2010-05-21 08:46:00 -0500 | [diff] [blame] | 492 | /* Make sure the above info reaches the primary CPU */ |
| 493 | smp_mb(); |
| 494 | |
| 495 | if (exception_level == 1) { |
| 496 | if (raw_spin_trylock(&dbg_master_lock)) |
| 497 | atomic_xchg(&kgdb_active, cpu); |
Jason Wessel | 6d90634 | 2010-05-20 21:04:27 -0500 | [diff] [blame] | 498 | goto cpu_master_loop; |
Jason Wessel | dfee3a7 | 2010-05-21 08:46:00 -0500 | [diff] [blame] | 499 | } |
Jason Wessel | 6d90634 | 2010-05-20 21:04:27 -0500 | [diff] [blame] | 500 | |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 501 | /* |
Jason Wessel | 62fae31 | 2010-04-02 11:47:02 -0500 | [diff] [blame] | 502 | * CPU will loop if it is a slave or request to become a kgdb |
| 503 | * master cpu and acquire the kgdb_active lock: |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 504 | */ |
Jason Wessel | 62fae31 | 2010-04-02 11:47:02 -0500 | [diff] [blame] | 505 | while (1) { |
Jason Wessel | dcc7871 | 2010-05-20 21:04:21 -0500 | [diff] [blame] | 506 | cpu_loop: |
| 507 | if (kgdb_info[cpu].exception_state & DCPU_NEXT_MASTER) { |
| 508 | kgdb_info[cpu].exception_state &= ~DCPU_NEXT_MASTER; |
| 509 | goto cpu_master_loop; |
| 510 | } else if (kgdb_info[cpu].exception_state & DCPU_WANT_MASTER) { |
Jason Wessel | dfee3a7 | 2010-05-21 08:46:00 -0500 | [diff] [blame] | 511 | if (raw_spin_trylock(&dbg_master_lock)) { |
| 512 | atomic_xchg(&kgdb_active, cpu); |
Jason Wessel | 62fae31 | 2010-04-02 11:47:02 -0500 | [diff] [blame] | 513 | break; |
Jason Wessel | dfee3a7 | 2010-05-21 08:46:00 -0500 | [diff] [blame] | 514 | } |
Jason Wessel | 62fae31 | 2010-04-02 11:47:02 -0500 | [diff] [blame] | 515 | } else if (kgdb_info[cpu].exception_state & DCPU_IS_SLAVE) { |
Jason Wessel | dfee3a7 | 2010-05-21 08:46:00 -0500 | [diff] [blame] | 516 | if (!raw_spin_is_locked(&dbg_slave_lock)) |
Jason Wessel | 62fae31 | 2010-04-02 11:47:02 -0500 | [diff] [blame] | 517 | goto return_normal; |
| 518 | } else { |
| 519 | return_normal: |
| 520 | /* Return to normal operation by executing any |
| 521 | * hw breakpoint fixup. |
| 522 | */ |
| 523 | if (arch_kgdb_ops.correct_hw_break) |
| 524 | arch_kgdb_ops.correct_hw_break(); |
Jason Wessel | 4da75b9 | 2010-04-02 11:57:18 -0500 | [diff] [blame] | 525 | if (trace_on) |
| 526 | tracing_on(); |
Jason Wessel | dfee3a7 | 2010-05-21 08:46:00 -0500 | [diff] [blame] | 527 | kgdb_info[cpu].exception_state &= |
| 528 | ~(DCPU_WANT_MASTER | DCPU_IS_SLAVE); |
| 529 | kgdb_info[cpu].enter_kgdb--; |
| 530 | smp_mb__before_atomic_dec(); |
| 531 | atomic_dec(&slaves_in_kgdb); |
Jason Wessel | 16cdc62 | 2010-08-06 11:47:14 -0500 | [diff] [blame] | 532 | dbg_touch_watchdogs(); |
Jason Wessel | 62fae31 | 2010-04-02 11:47:02 -0500 | [diff] [blame] | 533 | local_irq_restore(flags); |
| 534 | return 0; |
| 535 | } |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 536 | cpu_relax(); |
Jason Wessel | 62fae31 | 2010-04-02 11:47:02 -0500 | [diff] [blame] | 537 | } |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 538 | |
| 539 | /* |
Jason Wessel | 028e7b1 | 2009-12-11 08:43:17 -0600 | [diff] [blame] | 540 | * For single stepping, try to only enter on the processor |
| 541 | * that was single stepping. To gaurd against a deadlock, the |
| 542 | * kernel will only try for the value of sstep_tries before |
| 543 | * giving up and continuing on. |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 544 | */ |
| 545 | if (atomic_read(&kgdb_cpu_doing_single_step) != -1 && |
Jason Wessel | 028e7b1 | 2009-12-11 08:43:17 -0600 | [diff] [blame] | 546 | (kgdb_info[cpu].task && |
| 547 | kgdb_info[cpu].task->pid != kgdb_sstep_pid) && --sstep_tries) { |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 548 | atomic_set(&kgdb_active, -1); |
Jason Wessel | dfee3a7 | 2010-05-21 08:46:00 -0500 | [diff] [blame] | 549 | raw_spin_unlock(&dbg_master_lock); |
Jason Wessel | 16cdc62 | 2010-08-06 11:47:14 -0500 | [diff] [blame] | 550 | dbg_touch_watchdogs(); |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 551 | local_irq_restore(flags); |
| 552 | |
| 553 | goto acquirelock; |
| 554 | } |
| 555 | |
| 556 | if (!kgdb_io_ready(1)) { |
Jason Wessel | dcc7871 | 2010-05-20 21:04:21 -0500 | [diff] [blame] | 557 | kgdb_info[cpu].ret_state = 1; |
Jason Wessel | 53197fc | 2010-04-02 11:48:03 -0500 | [diff] [blame] | 558 | goto kgdb_restore; /* No I/O connection, resume the system */ |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 559 | } |
| 560 | |
| 561 | /* |
| 562 | * Don't enter if we have hit a removed breakpoint. |
| 563 | */ |
| 564 | if (kgdb_skipexception(ks->ex_vector, ks->linux_regs)) |
| 565 | goto kgdb_restore; |
| 566 | |
| 567 | /* Call the I/O driver's pre_exception routine */ |
Jason Wessel | 53197fc | 2010-04-02 11:48:03 -0500 | [diff] [blame] | 568 | if (dbg_io_ops->pre_exception) |
| 569 | dbg_io_ops->pre_exception(); |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 570 | |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 571 | /* |
| 572 | * Get the passive CPU lock which will hold all the non-primary |
| 573 | * CPU in a spin state while the debugger is active |
| 574 | */ |
Jason Wessel | dfee3a7 | 2010-05-21 08:46:00 -0500 | [diff] [blame] | 575 | if (!kgdb_single_step) |
| 576 | raw_spin_lock(&dbg_slave_lock); |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 577 | |
Jason Wessel | 56fb709 | 2008-04-01 16:55:27 -0500 | [diff] [blame] | 578 | #ifdef CONFIG_SMP |
| 579 | /* Signal the other CPUs to enter kgdb_wait() */ |
Jason Wessel | d7161a6 | 2008-09-26 10:36:41 -0500 | [diff] [blame] | 580 | if ((!kgdb_single_step) && kgdb_do_roundup) |
Jason Wessel | 56fb709 | 2008-04-01 16:55:27 -0500 | [diff] [blame] | 581 | kgdb_roundup_cpus(flags); |
| 582 | #endif |
| 583 | |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 584 | /* |
| 585 | * Wait for the other CPUs to be notified and be waiting for us: |
| 586 | */ |
Jason Wessel | dfee3a7 | 2010-05-21 08:46:00 -0500 | [diff] [blame] | 587 | while (kgdb_do_roundup && (atomic_read(&masters_in_kgdb) + |
| 588 | atomic_read(&slaves_in_kgdb)) != online_cpus) |
| 589 | cpu_relax(); |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 590 | |
| 591 | /* |
| 592 | * At this point the primary processor is completely |
| 593 | * in the debugger and all secondary CPUs are quiescent |
| 594 | */ |
Jason Wessel | dcc7871 | 2010-05-20 21:04:21 -0500 | [diff] [blame] | 595 | dbg_deactivate_sw_breakpoints(); |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 596 | kgdb_single_step = 0; |
Jason Wessel | d7161a6 | 2008-09-26 10:36:41 -0500 | [diff] [blame] | 597 | kgdb_contthread = current; |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 598 | exception_level = 0; |
Jason Wessel | 4da75b9 | 2010-04-02 11:57:18 -0500 | [diff] [blame] | 599 | trace_on = tracing_is_on(); |
| 600 | if (trace_on) |
| 601 | tracing_off(); |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 602 | |
Jason Wessel | dcc7871 | 2010-05-20 21:04:21 -0500 | [diff] [blame] | 603 | while (1) { |
| 604 | cpu_master_loop: |
| 605 | if (dbg_kdb_mode) { |
| 606 | kgdb_connected = 1; |
| 607 | error = kdb_stub(ks); |
Jason Wessel | 3fa43ab | 2010-08-05 09:22:25 -0500 | [diff] [blame] | 608 | if (error == -1) |
| 609 | continue; |
Jason Wessel | b0679c6 | 2010-07-21 19:27:07 -0500 | [diff] [blame] | 610 | kgdb_connected = 0; |
Jason Wessel | dcc7871 | 2010-05-20 21:04:21 -0500 | [diff] [blame] | 611 | } else { |
| 612 | error = gdb_serial_stub(ks); |
| 613 | } |
| 614 | |
| 615 | if (error == DBG_PASS_EVENT) { |
| 616 | dbg_kdb_mode = !dbg_kdb_mode; |
Jason Wessel | dcc7871 | 2010-05-20 21:04:21 -0500 | [diff] [blame] | 617 | } else if (error == DBG_SWITCH_CPU_EVENT) { |
Jason Wessel | 495363d | 2010-05-21 08:46:00 -0500 | [diff] [blame] | 618 | kgdb_info[dbg_switch_cpu].exception_state |= |
| 619 | DCPU_NEXT_MASTER; |
Jason Wessel | dcc7871 | 2010-05-20 21:04:21 -0500 | [diff] [blame] | 620 | goto cpu_loop; |
| 621 | } else { |
| 622 | kgdb_info[cpu].ret_state = error; |
| 623 | break; |
| 624 | } |
| 625 | } |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 626 | |
| 627 | /* Call the I/O driver's post_exception routine */ |
Jason Wessel | 53197fc | 2010-04-02 11:48:03 -0500 | [diff] [blame] | 628 | if (dbg_io_ops->post_exception) |
| 629 | dbg_io_ops->post_exception(); |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 630 | |
Jason Wessel | d7161a6 | 2008-09-26 10:36:41 -0500 | [diff] [blame] | 631 | if (!kgdb_single_step) { |
Jason Wessel | dfee3a7 | 2010-05-21 08:46:00 -0500 | [diff] [blame] | 632 | raw_spin_unlock(&dbg_slave_lock); |
| 633 | /* Wait till all the CPUs have quit from the debugger. */ |
| 634 | while (kgdb_do_roundup && atomic_read(&slaves_in_kgdb)) |
| 635 | cpu_relax(); |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 636 | } |
| 637 | |
| 638 | kgdb_restore: |
Jason Wessel | 028e7b1 | 2009-12-11 08:43:17 -0600 | [diff] [blame] | 639 | if (atomic_read(&kgdb_cpu_doing_single_step) != -1) { |
| 640 | int sstep_cpu = atomic_read(&kgdb_cpu_doing_single_step); |
| 641 | if (kgdb_info[sstep_cpu].task) |
| 642 | kgdb_sstep_pid = kgdb_info[sstep_cpu].task->pid; |
| 643 | else |
| 644 | kgdb_sstep_pid = 0; |
| 645 | } |
Dongdong Deng | c1bb9a9 | 2010-09-13 06:58:00 -0500 | [diff] [blame] | 646 | if (arch_kgdb_ops.correct_hw_break) |
| 647 | arch_kgdb_ops.correct_hw_break(); |
Jason Wessel | 4da75b9 | 2010-04-02 11:57:18 -0500 | [diff] [blame] | 648 | if (trace_on) |
| 649 | tracing_on(); |
Jason Wessel | dfee3a7 | 2010-05-21 08:46:00 -0500 | [diff] [blame] | 650 | |
| 651 | kgdb_info[cpu].exception_state &= |
| 652 | ~(DCPU_WANT_MASTER | DCPU_IS_SLAVE); |
| 653 | kgdb_info[cpu].enter_kgdb--; |
| 654 | smp_mb__before_atomic_dec(); |
| 655 | atomic_dec(&masters_in_kgdb); |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 656 | /* Free kgdb_active */ |
| 657 | atomic_set(&kgdb_active, -1); |
Jason Wessel | dfee3a7 | 2010-05-21 08:46:00 -0500 | [diff] [blame] | 658 | raw_spin_unlock(&dbg_master_lock); |
Jason Wessel | 16cdc62 | 2010-08-06 11:47:14 -0500 | [diff] [blame] | 659 | dbg_touch_watchdogs(); |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 660 | local_irq_restore(flags); |
| 661 | |
Jason Wessel | dcc7871 | 2010-05-20 21:04:21 -0500 | [diff] [blame] | 662 | return kgdb_info[cpu].ret_state; |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 663 | } |
| 664 | |
Jason Wessel | 62fae31 | 2010-04-02 11:47:02 -0500 | [diff] [blame] | 665 | /* |
| 666 | * kgdb_handle_exception() - main entry point from a kernel exception |
| 667 | * |
| 668 | * Locking hierarchy: |
| 669 | * interface locks, if any (begin_session) |
| 670 | * kgdb lock (kgdb_active) |
| 671 | */ |
| 672 | int |
| 673 | kgdb_handle_exception(int evector, int signo, int ecode, struct pt_regs *regs) |
| 674 | { |
| 675 | struct kgdb_state kgdb_var; |
| 676 | struct kgdb_state *ks = &kgdb_var; |
Jason Wessel | 62fae31 | 2010-04-02 11:47:02 -0500 | [diff] [blame] | 677 | |
| 678 | ks->cpu = raw_smp_processor_id(); |
| 679 | ks->ex_vector = evector; |
| 680 | ks->signo = signo; |
Jason Wessel | 62fae31 | 2010-04-02 11:47:02 -0500 | [diff] [blame] | 681 | ks->err_code = ecode; |
| 682 | ks->kgdb_usethreadid = 0; |
| 683 | ks->linux_regs = regs; |
| 684 | |
| 685 | if (kgdb_reenter_check(ks)) |
| 686 | return 0; /* Ouch, double exception ! */ |
Jason Wessel | dfee3a7 | 2010-05-21 08:46:00 -0500 | [diff] [blame] | 687 | if (kgdb_info[ks->cpu].enter_kgdb != 0) |
| 688 | return 0; |
| 689 | |
| 690 | return kgdb_cpu_enter(ks, regs, DCPU_WANT_MASTER); |
Jason Wessel | 62fae31 | 2010-04-02 11:47:02 -0500 | [diff] [blame] | 691 | } |
| 692 | |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 693 | int kgdb_nmicallback(int cpu, void *regs) |
| 694 | { |
| 695 | #ifdef CONFIG_SMP |
Jason Wessel | 62fae31 | 2010-04-02 11:47:02 -0500 | [diff] [blame] | 696 | struct kgdb_state kgdb_var; |
| 697 | struct kgdb_state *ks = &kgdb_var; |
| 698 | |
| 699 | memset(ks, 0, sizeof(struct kgdb_state)); |
| 700 | ks->cpu = cpu; |
| 701 | ks->linux_regs = regs; |
| 702 | |
Jason Wessel | dfee3a7 | 2010-05-21 08:46:00 -0500 | [diff] [blame] | 703 | if (kgdb_info[ks->cpu].enter_kgdb == 0 && |
| 704 | raw_spin_is_locked(&dbg_master_lock)) { |
| 705 | kgdb_cpu_enter(ks, regs, DCPU_IS_SLAVE); |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 706 | return 0; |
| 707 | } |
| 708 | #endif |
| 709 | return 1; |
| 710 | } |
| 711 | |
Jason Wessel | aabdc3b | 2008-06-24 10:52:55 -0500 | [diff] [blame] | 712 | static void kgdb_console_write(struct console *co, const char *s, |
| 713 | unsigned count) |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 714 | { |
| 715 | unsigned long flags; |
| 716 | |
| 717 | /* If we're debugging, or KGDB has not connected, don't try |
| 718 | * and print. */ |
Jason Wessel | dcc7871 | 2010-05-20 21:04:21 -0500 | [diff] [blame] | 719 | if (!kgdb_connected || atomic_read(&kgdb_active) != -1 || dbg_kdb_mode) |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 720 | return; |
| 721 | |
| 722 | local_irq_save(flags); |
Jason Wessel | 53197fc | 2010-04-02 11:48:03 -0500 | [diff] [blame] | 723 | gdbstub_msg_write(s, count); |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 724 | local_irq_restore(flags); |
| 725 | } |
| 726 | |
| 727 | static struct console kgdbcons = { |
| 728 | .name = "kgdb", |
| 729 | .write = kgdb_console_write, |
| 730 | .flags = CON_PRINTBUFFER | CON_ENABLED, |
| 731 | .index = -1, |
| 732 | }; |
| 733 | |
| 734 | #ifdef CONFIG_MAGIC_SYSRQ |
Dmitry Torokhov | 1495cc9 | 2010-08-17 21:15:46 -0700 | [diff] [blame] | 735 | static void sysrq_handle_dbg(int key) |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 736 | { |
Jason Wessel | 53197fc | 2010-04-02 11:48:03 -0500 | [diff] [blame] | 737 | if (!dbg_io_ops) { |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 738 | printk(KERN_CRIT "ERROR: No KGDB I/O module available\n"); |
| 739 | return; |
| 740 | } |
Jason Wessel | dcc7871 | 2010-05-20 21:04:21 -0500 | [diff] [blame] | 741 | if (!kgdb_connected) { |
| 742 | #ifdef CONFIG_KGDB_KDB |
| 743 | if (!dbg_kdb_mode) |
| 744 | printk(KERN_CRIT "KGDB or $3#33 for KDB\n"); |
| 745 | #else |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 746 | printk(KERN_CRIT "Entering KGDB\n"); |
Jason Wessel | dcc7871 | 2010-05-20 21:04:21 -0500 | [diff] [blame] | 747 | #endif |
| 748 | } |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 749 | |
| 750 | kgdb_breakpoint(); |
| 751 | } |
| 752 | |
Jason Wessel | 53197fc | 2010-04-02 11:48:03 -0500 | [diff] [blame] | 753 | static struct sysrq_key_op sysrq_dbg_op = { |
| 754 | .handler = sysrq_handle_dbg, |
Jason Wessel | 364b5b7 | 2009-05-13 21:56:59 -0500 | [diff] [blame] | 755 | .help_msg = "debug(G)", |
| 756 | .action_msg = "DEBUG", |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 757 | }; |
| 758 | #endif |
| 759 | |
Jason Wessel | 4402c15 | 2010-05-20 21:04:28 -0500 | [diff] [blame] | 760 | static int kgdb_panic_event(struct notifier_block *self, |
| 761 | unsigned long val, |
| 762 | void *data) |
| 763 | { |
| 764 | if (dbg_kdb_mode) |
| 765 | kdb_printf("PANIC: %s\n", (char *)data); |
| 766 | kgdb_breakpoint(); |
| 767 | return NOTIFY_DONE; |
| 768 | } |
| 769 | |
| 770 | static struct notifier_block kgdb_panic_event_nb = { |
| 771 | .notifier_call = kgdb_panic_event, |
| 772 | .priority = INT_MAX, |
| 773 | }; |
| 774 | |
Jason Wessel | 0b4b382 | 2010-05-20 21:04:29 -0500 | [diff] [blame] | 775 | void __weak kgdb_arch_late(void) |
| 776 | { |
| 777 | } |
| 778 | |
| 779 | void __init dbg_late_init(void) |
| 780 | { |
| 781 | dbg_is_early = false; |
| 782 | if (kgdb_io_module_registered) |
| 783 | kgdb_arch_late(); |
| 784 | kdb_init(KDB_INIT_FULL); |
| 785 | } |
| 786 | |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 787 | static void kgdb_register_callbacks(void) |
| 788 | { |
| 789 | if (!kgdb_io_module_registered) { |
| 790 | kgdb_io_module_registered = 1; |
| 791 | kgdb_arch_init(); |
Jason Wessel | 0b4b382 | 2010-05-20 21:04:29 -0500 | [diff] [blame] | 792 | if (!dbg_is_early) |
| 793 | kgdb_arch_late(); |
Jason Wessel | 4402c15 | 2010-05-20 21:04:28 -0500 | [diff] [blame] | 794 | atomic_notifier_chain_register(&panic_notifier_list, |
| 795 | &kgdb_panic_event_nb); |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 796 | #ifdef CONFIG_MAGIC_SYSRQ |
Jason Wessel | 53197fc | 2010-04-02 11:48:03 -0500 | [diff] [blame] | 797 | register_sysrq_key('g', &sysrq_dbg_op); |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 798 | #endif |
| 799 | if (kgdb_use_con && !kgdb_con_registered) { |
| 800 | register_console(&kgdbcons); |
| 801 | kgdb_con_registered = 1; |
| 802 | } |
| 803 | } |
| 804 | } |
| 805 | |
| 806 | static void kgdb_unregister_callbacks(void) |
| 807 | { |
| 808 | /* |
| 809 | * When this routine is called KGDB should unregister from the |
| 810 | * panic handler and clean up, making sure it is not handling any |
| 811 | * break exceptions at the time. |
| 812 | */ |
| 813 | if (kgdb_io_module_registered) { |
| 814 | kgdb_io_module_registered = 0; |
Jason Wessel | 4402c15 | 2010-05-20 21:04:28 -0500 | [diff] [blame] | 815 | atomic_notifier_chain_unregister(&panic_notifier_list, |
| 816 | &kgdb_panic_event_nb); |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 817 | kgdb_arch_exit(); |
| 818 | #ifdef CONFIG_MAGIC_SYSRQ |
Jason Wessel | 53197fc | 2010-04-02 11:48:03 -0500 | [diff] [blame] | 819 | unregister_sysrq_key('g', &sysrq_dbg_op); |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 820 | #endif |
| 821 | if (kgdb_con_registered) { |
| 822 | unregister_console(&kgdbcons); |
| 823 | kgdb_con_registered = 0; |
| 824 | } |
| 825 | } |
| 826 | } |
| 827 | |
Jason Wessel | 1cee5e3 | 2009-06-03 14:06:57 -0500 | [diff] [blame] | 828 | /* |
| 829 | * There are times a tasklet needs to be used vs a compiled in |
| 830 | * break point so as to cause an exception outside a kgdb I/O module, |
| 831 | * such as is the case with kgdboe, where calling a breakpoint in the |
| 832 | * I/O driver itself would be fatal. |
| 833 | */ |
| 834 | static void kgdb_tasklet_bpt(unsigned long ing) |
| 835 | { |
| 836 | kgdb_breakpoint(); |
| 837 | atomic_set(&kgdb_break_tasklet_var, 0); |
| 838 | } |
| 839 | |
| 840 | static DECLARE_TASKLET(kgdb_tasklet_breakpoint, kgdb_tasklet_bpt, 0); |
| 841 | |
| 842 | void kgdb_schedule_breakpoint(void) |
| 843 | { |
| 844 | if (atomic_read(&kgdb_break_tasklet_var) || |
| 845 | atomic_read(&kgdb_active) != -1 || |
| 846 | atomic_read(&kgdb_setting_breakpoint)) |
| 847 | return; |
| 848 | atomic_inc(&kgdb_break_tasklet_var); |
| 849 | tasklet_schedule(&kgdb_tasklet_breakpoint); |
| 850 | } |
| 851 | EXPORT_SYMBOL_GPL(kgdb_schedule_breakpoint); |
| 852 | |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 853 | static void kgdb_initial_breakpoint(void) |
| 854 | { |
| 855 | kgdb_break_asap = 0; |
| 856 | |
| 857 | printk(KERN_CRIT "kgdb: Waiting for connection from remote gdb...\n"); |
| 858 | kgdb_breakpoint(); |
| 859 | } |
| 860 | |
| 861 | /** |
Jason Wessel | 737a460 | 2008-03-07 16:34:16 -0600 | [diff] [blame] | 862 | * kgdb_register_io_module - register KGDB IO module |
Jason Wessel | 53197fc | 2010-04-02 11:48:03 -0500 | [diff] [blame] | 863 | * @new_dbg_io_ops: the io ops vector |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 864 | * |
| 865 | * Register it with the KGDB core. |
| 866 | */ |
Jason Wessel | 53197fc | 2010-04-02 11:48:03 -0500 | [diff] [blame] | 867 | int kgdb_register_io_module(struct kgdb_io *new_dbg_io_ops) |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 868 | { |
| 869 | int err; |
| 870 | |
| 871 | spin_lock(&kgdb_registration_lock); |
| 872 | |
Jason Wessel | 53197fc | 2010-04-02 11:48:03 -0500 | [diff] [blame] | 873 | if (dbg_io_ops) { |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 874 | spin_unlock(&kgdb_registration_lock); |
| 875 | |
| 876 | printk(KERN_ERR "kgdb: Another I/O driver is already " |
| 877 | "registered with KGDB.\n"); |
| 878 | return -EBUSY; |
| 879 | } |
| 880 | |
Jason Wessel | 53197fc | 2010-04-02 11:48:03 -0500 | [diff] [blame] | 881 | if (new_dbg_io_ops->init) { |
| 882 | err = new_dbg_io_ops->init(); |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 883 | if (err) { |
| 884 | spin_unlock(&kgdb_registration_lock); |
| 885 | return err; |
| 886 | } |
| 887 | } |
| 888 | |
Jason Wessel | 53197fc | 2010-04-02 11:48:03 -0500 | [diff] [blame] | 889 | dbg_io_ops = new_dbg_io_ops; |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 890 | |
| 891 | spin_unlock(&kgdb_registration_lock); |
| 892 | |
| 893 | printk(KERN_INFO "kgdb: Registered I/O driver %s.\n", |
Jason Wessel | 53197fc | 2010-04-02 11:48:03 -0500 | [diff] [blame] | 894 | new_dbg_io_ops->name); |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 895 | |
| 896 | /* Arm KGDB now. */ |
| 897 | kgdb_register_callbacks(); |
| 898 | |
| 899 | if (kgdb_break_asap) |
| 900 | kgdb_initial_breakpoint(); |
| 901 | |
| 902 | return 0; |
| 903 | } |
| 904 | EXPORT_SYMBOL_GPL(kgdb_register_io_module); |
| 905 | |
| 906 | /** |
| 907 | * kkgdb_unregister_io_module - unregister KGDB IO module |
Jason Wessel | 53197fc | 2010-04-02 11:48:03 -0500 | [diff] [blame] | 908 | * @old_dbg_io_ops: the io ops vector |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 909 | * |
| 910 | * Unregister it with the KGDB core. |
| 911 | */ |
Jason Wessel | 53197fc | 2010-04-02 11:48:03 -0500 | [diff] [blame] | 912 | void kgdb_unregister_io_module(struct kgdb_io *old_dbg_io_ops) |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 913 | { |
| 914 | BUG_ON(kgdb_connected); |
| 915 | |
| 916 | /* |
| 917 | * KGDB is no longer able to communicate out, so |
| 918 | * unregister our callbacks and reset state. |
| 919 | */ |
| 920 | kgdb_unregister_callbacks(); |
| 921 | |
| 922 | spin_lock(&kgdb_registration_lock); |
| 923 | |
Jason Wessel | 53197fc | 2010-04-02 11:48:03 -0500 | [diff] [blame] | 924 | WARN_ON_ONCE(dbg_io_ops != old_dbg_io_ops); |
| 925 | dbg_io_ops = NULL; |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 926 | |
| 927 | spin_unlock(&kgdb_registration_lock); |
| 928 | |
| 929 | printk(KERN_INFO |
| 930 | "kgdb: Unregistered I/O driver %s, debugger disabled.\n", |
Jason Wessel | 53197fc | 2010-04-02 11:48:03 -0500 | [diff] [blame] | 931 | old_dbg_io_ops->name); |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 932 | } |
| 933 | EXPORT_SYMBOL_GPL(kgdb_unregister_io_module); |
| 934 | |
Jason Wessel | dcc7871 | 2010-05-20 21:04:21 -0500 | [diff] [blame] | 935 | int dbg_io_get_char(void) |
| 936 | { |
| 937 | int ret = dbg_io_ops->read_char(); |
Jason Wessel | f5316b4 | 2010-05-20 21:04:22 -0500 | [diff] [blame] | 938 | if (ret == NO_POLL_CHAR) |
| 939 | return -1; |
Jason Wessel | dcc7871 | 2010-05-20 21:04:21 -0500 | [diff] [blame] | 940 | if (!dbg_kdb_mode) |
| 941 | return ret; |
| 942 | if (ret == 127) |
| 943 | return 8; |
| 944 | return ret; |
| 945 | } |
| 946 | |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 947 | /** |
| 948 | * kgdb_breakpoint - generate breakpoint exception |
| 949 | * |
| 950 | * This function will generate a breakpoint exception. It is used at the |
| 951 | * beginning of a program to sync up with a debugger and can be used |
| 952 | * otherwise as a quick means to stop program execution and "break" into |
| 953 | * the debugger. |
| 954 | */ |
| 955 | void kgdb_breakpoint(void) |
| 956 | { |
Jason Wessel | ae6bf53 | 2010-04-02 14:58:18 -0500 | [diff] [blame] | 957 | atomic_inc(&kgdb_setting_breakpoint); |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 958 | wmb(); /* Sync point before breakpoint */ |
| 959 | arch_kgdb_breakpoint(); |
| 960 | wmb(); /* Sync point after breakpoint */ |
Jason Wessel | ae6bf53 | 2010-04-02 14:58:18 -0500 | [diff] [blame] | 961 | atomic_dec(&kgdb_setting_breakpoint); |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 962 | } |
| 963 | EXPORT_SYMBOL_GPL(kgdb_breakpoint); |
| 964 | |
| 965 | static int __init opt_kgdb_wait(char *str) |
| 966 | { |
| 967 | kgdb_break_asap = 1; |
| 968 | |
Jason Wessel | dcc7871 | 2010-05-20 21:04:21 -0500 | [diff] [blame] | 969 | kdb_init(KDB_INIT_EARLY); |
Jason Wessel | dc7d552 | 2008-04-17 20:05:37 +0200 | [diff] [blame] | 970 | if (kgdb_io_module_registered) |
| 971 | kgdb_initial_breakpoint(); |
| 972 | |
| 973 | return 0; |
| 974 | } |
| 975 | |
| 976 | early_param("kgdbwait", opt_kgdb_wait); |