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Merge branch 'upstream/core' of git://git.kernel.org/pub/scm/linux/kernel/git/jeremy/xen
[net-next-2.6.git] / arch / x86 / kernel / kgdb.c
CommitLineData
82da3ff8
IM
1/*
2 * This program is free software; you can redistribute it and/or modify it
3 * under the terms of the GNU General Public License as published by the
4 * Free Software Foundation; either version 2, or (at your option) any
5 * later version.
6 *
7 * This program is distributed in the hope that it will be useful, but
8 * WITHOUT ANY WARRANTY; without even the implied warranty of
9 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
10 * General Public License for more details.
11 *
12 */
13
14/*
15 * Copyright (C) 2004 Amit S. Kale <amitkale@linsyssoft.com>
16 * Copyright (C) 2000-2001 VERITAS Software Corporation.
17 * Copyright (C) 2002 Andi Kleen, SuSE Labs
18 * Copyright (C) 2004 LinSysSoft Technologies Pvt. Ltd.
19 * Copyright (C) 2007 MontaVista Software, Inc.
20 * Copyright (C) 2007-2008 Jason Wessel, Wind River Systems, Inc.
21 */
22/****************************************************************************
23 * Contributor: Lake Stevens Instrument Division$
24 * Written by: Glenn Engel $
25 * Updated by: Amit Kale<akale@veritas.com>
26 * Updated by: Tom Rini <trini@kernel.crashing.org>
27 * Updated by: Jason Wessel <jason.wessel@windriver.com>
28 * Modified for 386 by Jim Kingdon, Cygnus Support.
29 * Origianl kgdb, compatibility with 2.1.xx kernel by
30 * David Grothe <dave@gcom.com>
31 * Integrated into 2.2.5 kernel by Tigran Aivazian <tigran@sco.com>
32 * X86_64 changes from Andi Kleen's patch merged by Jim Houston
33 */
34#include <linux/spinlock.h>
35#include <linux/kdebug.h>
36#include <linux/string.h>
37#include <linux/kernel.h>
38#include <linux/ptrace.h>
39#include <linux/sched.h>
40#include <linux/delay.h>
41#include <linux/kgdb.h>
42#include <linux/init.h>
43#include <linux/smp.h>
d3597524 44#include <linux/nmi.h>
cc096749 45#include <linux/hw_breakpoint.h>
82da3ff8 46
62edab90 47#include <asm/debugreg.h>
82da3ff8
IM
48#include <asm/apicdef.h>
49#include <asm/system.h>
7b6aa335 50#include <asm/apic.h>
82da3ff8 51
12bfa3de 52struct dbg_reg_def_t dbg_reg_def[DBG_MAX_REG_NUM] =
82da3ff8 53{
12bfa3de
JW
54#ifdef CONFIG_X86_32
55 { "ax", 4, offsetof(struct pt_regs, ax) },
56 { "cx", 4, offsetof(struct pt_regs, cx) },
57 { "dx", 4, offsetof(struct pt_regs, dx) },
58 { "bx", 4, offsetof(struct pt_regs, bx) },
59 { "sp", 4, offsetof(struct pt_regs, sp) },
60 { "bp", 4, offsetof(struct pt_regs, bp) },
61 { "si", 4, offsetof(struct pt_regs, si) },
62 { "di", 4, offsetof(struct pt_regs, di) },
63 { "ip", 4, offsetof(struct pt_regs, ip) },
64 { "flags", 4, offsetof(struct pt_regs, flags) },
65 { "cs", 4, offsetof(struct pt_regs, cs) },
66 { "ss", 4, offsetof(struct pt_regs, ss) },
67 { "ds", 4, offsetof(struct pt_regs, ds) },
68 { "es", 4, offsetof(struct pt_regs, es) },
69 { "fs", 4, -1 },
70 { "gs", 4, -1 },
71#else
72 { "ax", 8, offsetof(struct pt_regs, ax) },
73 { "bx", 8, offsetof(struct pt_regs, bx) },
74 { "cx", 8, offsetof(struct pt_regs, cx) },
75 { "dx", 8, offsetof(struct pt_regs, dx) },
76 { "si", 8, offsetof(struct pt_regs, dx) },
77 { "di", 8, offsetof(struct pt_regs, di) },
78 { "bp", 8, offsetof(struct pt_regs, bp) },
79 { "sp", 8, offsetof(struct pt_regs, sp) },
80 { "r8", 8, offsetof(struct pt_regs, r8) },
81 { "r9", 8, offsetof(struct pt_regs, r9) },
82 { "r10", 8, offsetof(struct pt_regs, r10) },
83 { "r11", 8, offsetof(struct pt_regs, r11) },
84 { "r12", 8, offsetof(struct pt_regs, r12) },
85 { "r13", 8, offsetof(struct pt_regs, r13) },
86 { "r14", 8, offsetof(struct pt_regs, r14) },
87 { "r15", 8, offsetof(struct pt_regs, r15) },
88 { "ip", 8, offsetof(struct pt_regs, ip) },
89 { "flags", 4, offsetof(struct pt_regs, flags) },
90 { "cs", 4, offsetof(struct pt_regs, cs) },
91 { "ss", 4, offsetof(struct pt_regs, ss) },
703a1edc 92#endif
12bfa3de
JW
93};
94
95int dbg_set_reg(int regno, void *mem, struct pt_regs *regs)
96{
97 if (
82da3ff8 98#ifdef CONFIG_X86_32
12bfa3de
JW
99 regno == GDB_SS || regno == GDB_FS || regno == GDB_GS ||
100#endif
101 regno == GDB_SP || regno == GDB_ORIG_AX)
102 return 0;
103
104 if (dbg_reg_def[regno].offset != -1)
105 memcpy((void *)regs + dbg_reg_def[regno].offset, mem,
106 dbg_reg_def[regno].size);
107 return 0;
108}
109
110char *dbg_get_reg(int regno, void *mem, struct pt_regs *regs)
111{
112 if (regno == GDB_ORIG_AX) {
113 memcpy(mem, &regs->orig_ax, sizeof(regs->orig_ax));
114 return "orig_ax";
cf6f196d 115 }
12bfa3de
JW
116 if (regno >= DBG_MAX_REG_NUM || regno < 0)
117 return NULL;
118
119 if (dbg_reg_def[regno].offset != -1)
120 memcpy(mem, (void *)regs + dbg_reg_def[regno].offset,
121 dbg_reg_def[regno].size);
122
123 switch (regno) {
124#ifdef CONFIG_X86_32
125 case GDB_SS:
126 if (!user_mode_vm(regs))
127 *(unsigned long *)mem = __KERNEL_DS;
128 break;
129 case GDB_SP:
130 if (!user_mode_vm(regs))
131 *(unsigned long *)mem = kernel_stack_pointer(regs);
132 break;
133 case GDB_GS:
134 case GDB_FS:
135 *(unsigned long *)mem = 0xFFFF;
136 break;
cf6f196d 137#endif
12bfa3de
JW
138 }
139 return dbg_reg_def[regno].name;
82da3ff8
IM
140}
141
142/**
143 * sleeping_thread_to_gdb_regs - Convert ptrace regs to GDB regs
144 * @gdb_regs: A pointer to hold the registers in the order GDB wants.
145 * @p: The &struct task_struct of the desired process.
146 *
147 * Convert the register values of the sleeping process in @p to
148 * the format that GDB expects.
149 * This function is called when kgdb does not have access to the
150 * &struct pt_regs and therefore it should fill the gdb registers
151 * @gdb_regs with what has been saved in &struct thread_struct
152 * thread field during switch_to.
153 */
154void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p)
155{
703a1edc
JW
156#ifndef CONFIG_X86_32
157 u32 *gdb_regs32 = (u32 *)gdb_regs;
158#endif
82da3ff8
IM
159 gdb_regs[GDB_AX] = 0;
160 gdb_regs[GDB_BX] = 0;
161 gdb_regs[GDB_CX] = 0;
162 gdb_regs[GDB_DX] = 0;
163 gdb_regs[GDB_SI] = 0;
164 gdb_regs[GDB_DI] = 0;
165 gdb_regs[GDB_BP] = *(unsigned long *)p->thread.sp;
166#ifdef CONFIG_X86_32
167 gdb_regs[GDB_DS] = __KERNEL_DS;
168 gdb_regs[GDB_ES] = __KERNEL_DS;
169 gdb_regs[GDB_PS] = 0;
170 gdb_regs[GDB_CS] = __KERNEL_CS;
171 gdb_regs[GDB_PC] = p->thread.ip;
172 gdb_regs[GDB_SS] = __KERNEL_DS;
173 gdb_regs[GDB_FS] = 0xFFFF;
174 gdb_regs[GDB_GS] = 0xFFFF;
175#else
703a1edc
JW
176 gdb_regs32[GDB_PS] = *(unsigned long *)(p->thread.sp + 8);
177 gdb_regs32[GDB_CS] = __KERNEL_CS;
178 gdb_regs32[GDB_SS] = __KERNEL_DS;
0c23590f 179 gdb_regs[GDB_PC] = 0;
82da3ff8
IM
180 gdb_regs[GDB_R8] = 0;
181 gdb_regs[GDB_R9] = 0;
182 gdb_regs[GDB_R10] = 0;
183 gdb_regs[GDB_R11] = 0;
184 gdb_regs[GDB_R12] = 0;
185 gdb_regs[GDB_R13] = 0;
186 gdb_regs[GDB_R14] = 0;
187 gdb_regs[GDB_R15] = 0;
188#endif
189 gdb_regs[GDB_SP] = p->thread.sp;
190}
191
64e9ee30
JW
192static struct hw_breakpoint {
193 unsigned enabled;
64e9ee30 194 unsigned long addr;
cc096749
JW
195 int len;
196 int type;
8c8aefce 197 struct perf_event * __percpu *pev;
df493935 198} breakinfo[HBP_NUM];
64e9ee30 199
031acd8c
JW
200static unsigned long early_dr7;
201
64e9ee30
JW
202static void kgdb_correct_hw_break(void)
203{
64e9ee30
JW
204 int breakno;
205
df493935 206 for (breakno = 0; breakno < HBP_NUM; breakno++) {
cc096749
JW
207 struct perf_event *bp;
208 struct arch_hw_breakpoint *info;
209 int val;
210 int cpu = raw_smp_processor_id();
211 if (!breakinfo[breakno].enabled)
212 continue;
031acd8c
JW
213 if (dbg_is_early) {
214 set_debugreg(breakinfo[breakno].addr, breakno);
215 early_dr7 |= encode_dr7(breakno,
216 breakinfo[breakno].len,
217 breakinfo[breakno].type);
218 set_debugreg(early_dr7, 7);
219 continue;
220 }
cc096749
JW
221 bp = *per_cpu_ptr(breakinfo[breakno].pev, cpu);
222 info = counter_arch_bp(bp);
223 if (bp->attr.disabled != 1)
224 continue;
225 bp->attr.bp_addr = breakinfo[breakno].addr;
226 bp->attr.bp_len = breakinfo[breakno].len;
227 bp->attr.bp_type = breakinfo[breakno].type;
228 info->address = breakinfo[breakno].addr;
229 info->len = breakinfo[breakno].len;
230 info->type = breakinfo[breakno].type;
231 val = arch_install_hw_breakpoint(bp);
232 if (!val)
233 bp->attr.disabled = 0;
64e9ee30 234 }
031acd8c
JW
235 if (!dbg_is_early)
236 hw_breakpoint_restore();
64e9ee30
JW
237}
238
5352ae63
JW
239static int hw_break_reserve_slot(int breakno)
240{
241 int cpu;
242 int cnt = 0;
243 struct perf_event **pevent;
244
031acd8c
JW
245 if (dbg_is_early)
246 return 0;
247
5352ae63
JW
248 for_each_online_cpu(cpu) {
249 cnt++;
250 pevent = per_cpu_ptr(breakinfo[breakno].pev, cpu);
251 if (dbg_reserve_bp_slot(*pevent))
252 goto fail;
253 }
254
255 return 0;
256
257fail:
258 for_each_online_cpu(cpu) {
259 cnt--;
260 if (!cnt)
261 break;
262 pevent = per_cpu_ptr(breakinfo[breakno].pev, cpu);
263 dbg_release_bp_slot(*pevent);
264 }
265 return -1;
266}
267
268static int hw_break_release_slot(int breakno)
269{
270 struct perf_event **pevent;
271 int cpu;
272
031acd8c
JW
273 if (dbg_is_early)
274 return 0;
275
5352ae63
JW
276 for_each_online_cpu(cpu) {
277 pevent = per_cpu_ptr(breakinfo[breakno].pev, cpu);
278 if (dbg_release_bp_slot(*pevent))
279 /*
280 * The debugger is responisble for handing the retry on
281 * remove failure.
282 */
283 return -1;
284 }
285 return 0;
286}
287
64e9ee30
JW
288static int
289kgdb_remove_hw_break(unsigned long addr, int len, enum kgdb_bptype bptype)
290{
291 int i;
292
df493935 293 for (i = 0; i < HBP_NUM; i++)
64e9ee30
JW
294 if (breakinfo[i].addr == addr && breakinfo[i].enabled)
295 break;
df493935 296 if (i == HBP_NUM)
64e9ee30
JW
297 return -1;
298
5352ae63
JW
299 if (hw_break_release_slot(i)) {
300 printk(KERN_ERR "Cannot remove hw breakpoint at %lx\n", addr);
301 return -1;
302 }
64e9ee30
JW
303 breakinfo[i].enabled = 0;
304
305 return 0;
306}
307
308static void kgdb_remove_all_hw_break(void)
309{
310 int i;
cc096749
JW
311 int cpu = raw_smp_processor_id();
312 struct perf_event *bp;
64e9ee30 313
df493935 314 for (i = 0; i < HBP_NUM; i++) {
cc096749
JW
315 if (!breakinfo[i].enabled)
316 continue;
317 bp = *per_cpu_ptr(breakinfo[i].pev, cpu);
318 if (bp->attr.disabled == 1)
319 continue;
031acd8c
JW
320 if (dbg_is_early)
321 early_dr7 &= ~encode_dr7(i, breakinfo[i].len,
322 breakinfo[i].type);
323 else
324 arch_uninstall_hw_breakpoint(bp);
cc096749
JW
325 bp->attr.disabled = 1;
326 }
64e9ee30
JW
327}
328
329static int
330kgdb_set_hw_break(unsigned long addr, int len, enum kgdb_bptype bptype)
331{
64e9ee30
JW
332 int i;
333
df493935 334 for (i = 0; i < HBP_NUM; i++)
64e9ee30
JW
335 if (!breakinfo[i].enabled)
336 break;
df493935 337 if (i == HBP_NUM)
64e9ee30
JW
338 return -1;
339
340 switch (bptype) {
341 case BP_HARDWARE_BREAKPOINT:
cc096749
JW
342 len = 1;
343 breakinfo[i].type = X86_BREAKPOINT_EXECUTE;
64e9ee30
JW
344 break;
345 case BP_WRITE_WATCHPOINT:
cc096749 346 breakinfo[i].type = X86_BREAKPOINT_WRITE;
64e9ee30
JW
347 break;
348 case BP_ACCESS_WATCHPOINT:
cc096749 349 breakinfo[i].type = X86_BREAKPOINT_RW;
64e9ee30
JW
350 break;
351 default:
352 return -1;
353 }
cc096749
JW
354 switch (len) {
355 case 1:
356 breakinfo[i].len = X86_BREAKPOINT_LEN_1;
357 break;
358 case 2:
359 breakinfo[i].len = X86_BREAKPOINT_LEN_2;
360 break;
361 case 4:
362 breakinfo[i].len = X86_BREAKPOINT_LEN_4;
363 break;
364#ifdef CONFIG_X86_64
365 case 8:
366 breakinfo[i].len = X86_BREAKPOINT_LEN_8;
367 break;
368#endif
369 default:
64e9ee30 370 return -1;
cc096749 371 }
64e9ee30 372 breakinfo[i].addr = addr;
5352ae63
JW
373 if (hw_break_reserve_slot(i)) {
374 breakinfo[i].addr = 0;
375 return -1;
376 }
cc096749 377 breakinfo[i].enabled = 1;
64e9ee30
JW
378
379 return 0;
380}
381
382/**
383 * kgdb_disable_hw_debug - Disable hardware debugging while we in kgdb.
384 * @regs: Current &struct pt_regs.
385 *
386 * This function will be called if the particular architecture must
387 * disable hardware debugging while it is processing gdb packets or
388 * handling exception.
389 */
d7ba979d 390static void kgdb_disable_hw_debug(struct pt_regs *regs)
64e9ee30 391{
cc096749
JW
392 int i;
393 int cpu = raw_smp_processor_id();
394 struct perf_event *bp;
395
64e9ee30
JW
396 /* Disable hardware debugging while we are in kgdb: */
397 set_debugreg(0UL, 7);
df493935 398 for (i = 0; i < HBP_NUM; i++) {
cc096749
JW
399 if (!breakinfo[i].enabled)
400 continue;
031acd8c
JW
401 if (dbg_is_early) {
402 early_dr7 &= ~encode_dr7(i, breakinfo[i].len,
403 breakinfo[i].type);
404 continue;
405 }
cc096749
JW
406 bp = *per_cpu_ptr(breakinfo[i].pev, cpu);
407 if (bp->attr.disabled == 1)
408 continue;
409 arch_uninstall_hw_breakpoint(bp);
410 bp->attr.disabled = 1;
411 }
64e9ee30
JW
412}
413
82da3ff8
IM
414#ifdef CONFIG_SMP
415/**
416 * kgdb_roundup_cpus - Get other CPUs into a holding pattern
417 * @flags: Current IRQ state
418 *
419 * On SMP systems, we need to get the attention of the other CPUs
420 * and get them be in a known state. This should do what is needed
421 * to get the other CPUs to call kgdb_wait(). Note that on some arches,
422 * the NMI approach is not used for rounding up all the CPUs. For example,
423 * in case of MIPS, smp_call_function() is used to roundup CPUs. In
424 * this case, we have to make sure that interrupts are enabled before
425 * calling smp_call_function(). The argument to this function is
426 * the flags that will be used when restoring the interrupts. There is
427 * local_irq_save() call before kgdb_roundup_cpus().
428 *
429 * On non-SMP systems, this is not called.
430 */
431void kgdb_roundup_cpus(unsigned long flags)
432{
dac5f412 433 apic->send_IPI_allbutself(APIC_DM_NMI);
82da3ff8
IM
434}
435#endif
436
437/**
438 * kgdb_arch_handle_exception - Handle architecture specific GDB packets.
439 * @vector: The error vector of the exception that happened.
440 * @signo: The signal number of the exception that happened.
441 * @err_code: The error code of the exception that happened.
442 * @remcom_in_buffer: The buffer of the packet we have read.
443 * @remcom_out_buffer: The buffer of %BUFMAX bytes to write a packet into.
444 * @regs: The &struct pt_regs of the current process.
445 *
446 * This function MUST handle the 'c' and 's' command packets,
447 * as well packets to set / remove a hardware breakpoint, if used.
448 * If there are additional packets which the hardware needs to handle,
449 * they are handled here. The code should return -1 if it wants to
450 * process more packets, and a %0 or %1 if it wants to exit from the
451 * kgdb callback.
452 */
453int kgdb_arch_handle_exception(int e_vector, int signo, int err_code,
454 char *remcomInBuffer, char *remcomOutBuffer,
455 struct pt_regs *linux_regs)
456{
457 unsigned long addr;
458 char *ptr;
82da3ff8
IM
459
460 switch (remcomInBuffer[0]) {
461 case 'c':
462 case 's':
463 /* try to read optional parameter, pc unchanged if no parm */
464 ptr = &remcomInBuffer[1];
465 if (kgdb_hex2long(&ptr, &addr))
466 linux_regs->ip = addr;
737a460f
JW
467 case 'D':
468 case 'k':
82da3ff8 469 /* clear the trace bit */
fda31d7d 470 linux_regs->flags &= ~X86_EFLAGS_TF;
82da3ff8
IM
471 atomic_set(&kgdb_cpu_doing_single_step, -1);
472
473 /* set the trace bit if we're stepping */
474 if (remcomInBuffer[0] == 's') {
fda31d7d 475 linux_regs->flags |= X86_EFLAGS_TF;
d7161a65
JW
476 atomic_set(&kgdb_cpu_doing_single_step,
477 raw_smp_processor_id());
82da3ff8
IM
478 }
479
480 return 0;
481 }
482
483 /* this means that we do not want to exit from the handler: */
484 return -1;
485}
486
487static inline int
488single_step_cont(struct pt_regs *regs, struct die_args *args)
489{
490 /*
491 * Single step exception from kernel space to user space so
492 * eat the exception and continue the process:
493 */
494 printk(KERN_ERR "KGDB: trap/step from kernel to user space, "
495 "resuming...\n");
496 kgdb_arch_handle_exception(args->trapnr, args->signr,
497 args->err, "c", "", regs);
62edab90
P
498 /*
499 * Reset the BS bit in dr6 (pointed by args->err) to
500 * denote completion of processing
501 */
502 (*(unsigned long *)ERR_PTR(args->err)) &= ~DR_STEP;
82da3ff8
IM
503
504 return NOTIFY_STOP;
505}
506
d3597524
JW
507static int was_in_debug_nmi[NR_CPUS];
508
82da3ff8
IM
509static int __kgdb_notify(struct die_args *args, unsigned long cmd)
510{
511 struct pt_regs *regs = args->regs;
512
513 switch (cmd) {
514 case DIE_NMI:
515 if (atomic_read(&kgdb_active) != -1) {
516 /* KGDB CPU roundup */
517 kgdb_nmicallback(raw_smp_processor_id(), regs);
d3597524
JW
518 was_in_debug_nmi[raw_smp_processor_id()] = 1;
519 touch_nmi_watchdog();
82da3ff8
IM
520 return NOTIFY_STOP;
521 }
522 return NOTIFY_DONE;
523
524 case DIE_NMI_IPI:
e85ceae9 525 /* Just ignore, we will handle the roundup on DIE_NMI. */
d3597524
JW
526 return NOTIFY_DONE;
527
528 case DIE_NMIUNKNOWN:
529 if (was_in_debug_nmi[raw_smp_processor_id()]) {
530 was_in_debug_nmi[raw_smp_processor_id()] = 0;
82da3ff8
IM
531 return NOTIFY_STOP;
532 }
533 return NOTIFY_DONE;
534
535 case DIE_NMIWATCHDOG:
536 if (atomic_read(&kgdb_active) != -1) {
537 /* KGDB CPU roundup: */
538 kgdb_nmicallback(raw_smp_processor_id(), regs);
539 return NOTIFY_STOP;
540 }
541 /* Enter debugger: */
542 break;
543
544 case DIE_DEBUG:
cc096749 545 if (atomic_read(&kgdb_cpu_doing_single_step) != -1) {
d7161a65
JW
546 if (user_mode(regs))
547 return single_step_cont(regs, args);
548 break;
549 } else if (test_thread_flag(TIF_SINGLESTEP))
550 /* This means a user thread is single stepping
551 * a system call which should be ignored
552 */
553 return NOTIFY_DONE;
82da3ff8
IM
554 /* fall through */
555 default:
556 if (user_mode(regs))
557 return NOTIFY_DONE;
558 }
559
f503b5ae 560 if (kgdb_handle_exception(args->trapnr, args->signr, cmd, regs))
82da3ff8
IM
561 return NOTIFY_DONE;
562
737a460f
JW
563 /* Must touch watchdog before return to normal operation */
564 touch_nmi_watchdog();
82da3ff8
IM
565 return NOTIFY_STOP;
566}
567
f503b5ae
JW
568int kgdb_ll_trap(int cmd, const char *str,
569 struct pt_regs *regs, long err, int trap, int sig)
570{
571 struct die_args args = {
572 .regs = regs,
573 .str = str,
574 .err = err,
575 .trapnr = trap,
576 .signr = sig,
577
578 };
579
580 if (!kgdb_io_module_registered)
581 return NOTIFY_DONE;
582
583 return __kgdb_notify(&args, cmd);
584}
f503b5ae 585
82da3ff8
IM
586static int
587kgdb_notify(struct notifier_block *self, unsigned long cmd, void *ptr)
588{
589 unsigned long flags;
590 int ret;
591
592 local_irq_save(flags);
593 ret = __kgdb_notify(ptr, cmd);
594 local_irq_restore(flags);
595
596 return ret;
597}
598
599static struct notifier_block kgdb_notifier = {
600 .notifier_call = kgdb_notify,
601
602 /*
603 * Lowest-prio notifier priority, we want to be notified last:
604 */
605 .priority = -INT_MAX,
606};
607
608/**
609 * kgdb_arch_init - Perform any architecture specific initalization.
610 *
611 * This function will handle the initalization of any architecture
612 * specific callbacks.
613 */
614int kgdb_arch_init(void)
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615{
616 return register_die_notifier(&kgdb_notifier);
617}
618
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619static void kgdb_hw_overflow_handler(struct perf_event *event, int nmi,
620 struct perf_sample_data *data, struct pt_regs *regs)
621{
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622 struct task_struct *tsk = current;
623 int i;
624
625 for (i = 0; i < 4; i++)
626 if (breakinfo[i].enabled)
627 tsk->thread.debugreg6 |= (DR_TRAP0 << i);
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628}
629
0b4b3827 630void kgdb_arch_late(void)
82da3ff8 631{
cc096749 632 int i, cpu;
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633 struct perf_event_attr attr;
634 struct perf_event **pevent;
635
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636 /*
637 * Pre-allocate the hw breakpoint structions in the non-atomic
638 * portion of kgdb because this operation requires mutexs to
639 * complete.
640 */
ab310b5e 641 hw_breakpoint_init(&attr);
cc096749 642 attr.bp_addr = (unsigned long)kgdb_arch_init;
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643 attr.bp_len = HW_BREAKPOINT_LEN_1;
644 attr.bp_type = HW_BREAKPOINT_W;
645 attr.disabled = 1;
df493935 646 for (i = 0; i < HBP_NUM; i++) {
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647 if (breakinfo[i].pev)
648 continue;
cc096749 649 breakinfo[i].pev = register_wide_hw_breakpoint(&attr, NULL);
91b152aa 650 if (IS_ERR((void * __force)breakinfo[i].pev)) {
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651 printk(KERN_ERR "kgdb: Could not allocate hw"
652 "breakpoints\nDisabling the kernel debugger\n");
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653 breakinfo[i].pev = NULL;
654 kgdb_arch_exit();
0b4b3827 655 return;
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656 }
657 for_each_online_cpu(cpu) {
658 pevent = per_cpu_ptr(breakinfo[i].pev, cpu);
659 pevent[0]->hw.sample_period = 1;
ba773f7c 660 pevent[0]->overflow_handler = kgdb_hw_overflow_handler;
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661 if (pevent[0]->destroy != NULL) {
662 pevent[0]->destroy = NULL;
663 release_bp_slot(*pevent);
664 }
665 }
666 }
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667}
668
669/**
670 * kgdb_arch_exit - Perform any architecture specific uninitalization.
671 *
672 * This function will handle the uninitalization of any architecture
673 * specific callbacks, for dynamic registration and unregistration.
674 */
675void kgdb_arch_exit(void)
676{
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677 int i;
678 for (i = 0; i < 4; i++) {
679 if (breakinfo[i].pev) {
680 unregister_wide_hw_breakpoint(breakinfo[i].pev);
681 breakinfo[i].pev = NULL;
682 }
683 }
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684 unregister_die_notifier(&kgdb_notifier);
685}
686
687/**
688 *
689 * kgdb_skipexception - Bail out of KGDB when we've been triggered.
690 * @exception: Exception vector number
691 * @regs: Current &struct pt_regs.
692 *
693 * On some architectures we need to skip a breakpoint exception when
694 * it occurs after a breakpoint has been removed.
695 *
696 * Skip an int3 exception when it occurs after a breakpoint has been
697 * removed. Backtrack eip by 1 since the int3 would have caused it to
698 * increment by 1.
699 */
700int kgdb_skipexception(int exception, struct pt_regs *regs)
701{
702 if (exception == 3 && kgdb_isremovedbreak(regs->ip - 1)) {
703 regs->ip -= 1;
704 return 1;
705 }
706 return 0;
707}
708
709unsigned long kgdb_arch_pc(int exception, struct pt_regs *regs)
710{
711 if (exception == 3)
712 return instruction_pointer(regs) - 1;
713 return instruction_pointer(regs);
714}
715
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716void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long ip)
717{
718 regs->ip = ip;
719}
720
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721struct kgdb_arch arch_kgdb_ops = {
722 /* Breakpoint instruction: */
723 .gdb_bpt_instr = { 0xcc },
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724 .flags = KGDB_HW_BREAKPOINT,
725 .set_hw_breakpoint = kgdb_set_hw_break,
726 .remove_hw_breakpoint = kgdb_remove_hw_break,
d7ba979d 727 .disable_hw_break = kgdb_disable_hw_debug,
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728 .remove_all_hw_break = kgdb_remove_all_hw_break,
729 .correct_hw_break = kgdb_correct_hw_break,
82da3ff8 730};