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Merge branch 'topic/adsp' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie...
[GitHub/mt8127/android_kernel_alcatel_ttab.git] / arch / x86 / kernel / kgdb.c
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>
44 #include <linux/nmi.h>
45 #include <linux/hw_breakpoint.h>
46 #include <linux/uaccess.h>
47 #include <linux/memory.h>
48
49 #include <asm/debugreg.h>
50 #include <asm/apicdef.h>
51 #include <asm/apic.h>
52 #include <asm/nmi.h>
53
54 struct dbg_reg_def_t dbg_reg_def[DBG_MAX_REG_NUM] =
55 {
56 #ifdef CONFIG_X86_32
57 { "ax", 4, offsetof(struct pt_regs, ax) },
58 { "cx", 4, offsetof(struct pt_regs, cx) },
59 { "dx", 4, offsetof(struct pt_regs, dx) },
60 { "bx", 4, offsetof(struct pt_regs, bx) },
61 { "sp", 4, offsetof(struct pt_regs, sp) },
62 { "bp", 4, offsetof(struct pt_regs, bp) },
63 { "si", 4, offsetof(struct pt_regs, si) },
64 { "di", 4, offsetof(struct pt_regs, di) },
65 { "ip", 4, offsetof(struct pt_regs, ip) },
66 { "flags", 4, offsetof(struct pt_regs, flags) },
67 { "cs", 4, offsetof(struct pt_regs, cs) },
68 { "ss", 4, offsetof(struct pt_regs, ss) },
69 { "ds", 4, offsetof(struct pt_regs, ds) },
70 { "es", 4, offsetof(struct pt_regs, es) },
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) },
92 { "ds", 4, -1 },
93 { "es", 4, -1 },
94 #endif
95 { "fs", 4, -1 },
96 { "gs", 4, -1 },
97 };
98
99 int dbg_set_reg(int regno, void *mem, struct pt_regs *regs)
100 {
101 if (
102 #ifdef CONFIG_X86_32
103 regno == GDB_SS || regno == GDB_FS || regno == GDB_GS ||
104 #endif
105 regno == GDB_SP || regno == GDB_ORIG_AX)
106 return 0;
107
108 if (dbg_reg_def[regno].offset != -1)
109 memcpy((void *)regs + dbg_reg_def[regno].offset, mem,
110 dbg_reg_def[regno].size);
111 return 0;
112 }
113
114 char *dbg_get_reg(int regno, void *mem, struct pt_regs *regs)
115 {
116 if (regno == GDB_ORIG_AX) {
117 memcpy(mem, &regs->orig_ax, sizeof(regs->orig_ax));
118 return "orig_ax";
119 }
120 if (regno >= DBG_MAX_REG_NUM || regno < 0)
121 return NULL;
122
123 if (dbg_reg_def[regno].offset != -1)
124 memcpy(mem, (void *)regs + dbg_reg_def[regno].offset,
125 dbg_reg_def[regno].size);
126
127 #ifdef CONFIG_X86_32
128 switch (regno) {
129 case GDB_SS:
130 if (!user_mode_vm(regs))
131 *(unsigned long *)mem = __KERNEL_DS;
132 break;
133 case GDB_SP:
134 if (!user_mode_vm(regs))
135 *(unsigned long *)mem = kernel_stack_pointer(regs);
136 break;
137 case GDB_GS:
138 case GDB_FS:
139 *(unsigned long *)mem = 0xFFFF;
140 break;
141 }
142 #endif
143 return dbg_reg_def[regno].name;
144 }
145
146 /**
147 * sleeping_thread_to_gdb_regs - Convert ptrace regs to GDB regs
148 * @gdb_regs: A pointer to hold the registers in the order GDB wants.
149 * @p: The &struct task_struct of the desired process.
150 *
151 * Convert the register values of the sleeping process in @p to
152 * the format that GDB expects.
153 * This function is called when kgdb does not have access to the
154 * &struct pt_regs and therefore it should fill the gdb registers
155 * @gdb_regs with what has been saved in &struct thread_struct
156 * thread field during switch_to.
157 */
158 void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p)
159 {
160 #ifndef CONFIG_X86_32
161 u32 *gdb_regs32 = (u32 *)gdb_regs;
162 #endif
163 gdb_regs[GDB_AX] = 0;
164 gdb_regs[GDB_BX] = 0;
165 gdb_regs[GDB_CX] = 0;
166 gdb_regs[GDB_DX] = 0;
167 gdb_regs[GDB_SI] = 0;
168 gdb_regs[GDB_DI] = 0;
169 gdb_regs[GDB_BP] = *(unsigned long *)p->thread.sp;
170 #ifdef CONFIG_X86_32
171 gdb_regs[GDB_DS] = __KERNEL_DS;
172 gdb_regs[GDB_ES] = __KERNEL_DS;
173 gdb_regs[GDB_PS] = 0;
174 gdb_regs[GDB_CS] = __KERNEL_CS;
175 gdb_regs[GDB_PC] = p->thread.ip;
176 gdb_regs[GDB_SS] = __KERNEL_DS;
177 gdb_regs[GDB_FS] = 0xFFFF;
178 gdb_regs[GDB_GS] = 0xFFFF;
179 #else
180 gdb_regs32[GDB_PS] = *(unsigned long *)(p->thread.sp + 8);
181 gdb_regs32[GDB_CS] = __KERNEL_CS;
182 gdb_regs32[GDB_SS] = __KERNEL_DS;
183 gdb_regs[GDB_PC] = 0;
184 gdb_regs[GDB_R8] = 0;
185 gdb_regs[GDB_R9] = 0;
186 gdb_regs[GDB_R10] = 0;
187 gdb_regs[GDB_R11] = 0;
188 gdb_regs[GDB_R12] = 0;
189 gdb_regs[GDB_R13] = 0;
190 gdb_regs[GDB_R14] = 0;
191 gdb_regs[GDB_R15] = 0;
192 #endif
193 gdb_regs[GDB_SP] = p->thread.sp;
194 }
195
196 static struct hw_breakpoint {
197 unsigned enabled;
198 unsigned long addr;
199 int len;
200 int type;
201 struct perf_event * __percpu *pev;
202 } breakinfo[HBP_NUM];
203
204 static unsigned long early_dr7;
205
206 static void kgdb_correct_hw_break(void)
207 {
208 int breakno;
209
210 for (breakno = 0; breakno < HBP_NUM; breakno++) {
211 struct perf_event *bp;
212 struct arch_hw_breakpoint *info;
213 int val;
214 int cpu = raw_smp_processor_id();
215 if (!breakinfo[breakno].enabled)
216 continue;
217 if (dbg_is_early) {
218 set_debugreg(breakinfo[breakno].addr, breakno);
219 early_dr7 |= encode_dr7(breakno,
220 breakinfo[breakno].len,
221 breakinfo[breakno].type);
222 set_debugreg(early_dr7, 7);
223 continue;
224 }
225 bp = *per_cpu_ptr(breakinfo[breakno].pev, cpu);
226 info = counter_arch_bp(bp);
227 if (bp->attr.disabled != 1)
228 continue;
229 bp->attr.bp_addr = breakinfo[breakno].addr;
230 bp->attr.bp_len = breakinfo[breakno].len;
231 bp->attr.bp_type = breakinfo[breakno].type;
232 info->address = breakinfo[breakno].addr;
233 info->len = breakinfo[breakno].len;
234 info->type = breakinfo[breakno].type;
235 val = arch_install_hw_breakpoint(bp);
236 if (!val)
237 bp->attr.disabled = 0;
238 }
239 if (!dbg_is_early)
240 hw_breakpoint_restore();
241 }
242
243 static int hw_break_reserve_slot(int breakno)
244 {
245 int cpu;
246 int cnt = 0;
247 struct perf_event **pevent;
248
249 if (dbg_is_early)
250 return 0;
251
252 for_each_online_cpu(cpu) {
253 cnt++;
254 pevent = per_cpu_ptr(breakinfo[breakno].pev, cpu);
255 if (dbg_reserve_bp_slot(*pevent))
256 goto fail;
257 }
258
259 return 0;
260
261 fail:
262 for_each_online_cpu(cpu) {
263 cnt--;
264 if (!cnt)
265 break;
266 pevent = per_cpu_ptr(breakinfo[breakno].pev, cpu);
267 dbg_release_bp_slot(*pevent);
268 }
269 return -1;
270 }
271
272 static int hw_break_release_slot(int breakno)
273 {
274 struct perf_event **pevent;
275 int cpu;
276
277 if (dbg_is_early)
278 return 0;
279
280 for_each_online_cpu(cpu) {
281 pevent = per_cpu_ptr(breakinfo[breakno].pev, cpu);
282 if (dbg_release_bp_slot(*pevent))
283 /*
284 * The debugger is responsible for handing the retry on
285 * remove failure.
286 */
287 return -1;
288 }
289 return 0;
290 }
291
292 static int
293 kgdb_remove_hw_break(unsigned long addr, int len, enum kgdb_bptype bptype)
294 {
295 int i;
296
297 for (i = 0; i < HBP_NUM; i++)
298 if (breakinfo[i].addr == addr && breakinfo[i].enabled)
299 break;
300 if (i == HBP_NUM)
301 return -1;
302
303 if (hw_break_release_slot(i)) {
304 printk(KERN_ERR "Cannot remove hw breakpoint at %lx\n", addr);
305 return -1;
306 }
307 breakinfo[i].enabled = 0;
308
309 return 0;
310 }
311
312 static void kgdb_remove_all_hw_break(void)
313 {
314 int i;
315 int cpu = raw_smp_processor_id();
316 struct perf_event *bp;
317
318 for (i = 0; i < HBP_NUM; i++) {
319 if (!breakinfo[i].enabled)
320 continue;
321 bp = *per_cpu_ptr(breakinfo[i].pev, cpu);
322 if (!bp->attr.disabled) {
323 arch_uninstall_hw_breakpoint(bp);
324 bp->attr.disabled = 1;
325 continue;
326 }
327 if (dbg_is_early)
328 early_dr7 &= ~encode_dr7(i, breakinfo[i].len,
329 breakinfo[i].type);
330 else if (hw_break_release_slot(i))
331 printk(KERN_ERR "KGDB: hw bpt remove failed %lx\n",
332 breakinfo[i].addr);
333 breakinfo[i].enabled = 0;
334 }
335 }
336
337 static int
338 kgdb_set_hw_break(unsigned long addr, int len, enum kgdb_bptype bptype)
339 {
340 int i;
341
342 for (i = 0; i < HBP_NUM; i++)
343 if (!breakinfo[i].enabled)
344 break;
345 if (i == HBP_NUM)
346 return -1;
347
348 switch (bptype) {
349 case BP_HARDWARE_BREAKPOINT:
350 len = 1;
351 breakinfo[i].type = X86_BREAKPOINT_EXECUTE;
352 break;
353 case BP_WRITE_WATCHPOINT:
354 breakinfo[i].type = X86_BREAKPOINT_WRITE;
355 break;
356 case BP_ACCESS_WATCHPOINT:
357 breakinfo[i].type = X86_BREAKPOINT_RW;
358 break;
359 default:
360 return -1;
361 }
362 switch (len) {
363 case 1:
364 breakinfo[i].len = X86_BREAKPOINT_LEN_1;
365 break;
366 case 2:
367 breakinfo[i].len = X86_BREAKPOINT_LEN_2;
368 break;
369 case 4:
370 breakinfo[i].len = X86_BREAKPOINT_LEN_4;
371 break;
372 #ifdef CONFIG_X86_64
373 case 8:
374 breakinfo[i].len = X86_BREAKPOINT_LEN_8;
375 break;
376 #endif
377 default:
378 return -1;
379 }
380 breakinfo[i].addr = addr;
381 if (hw_break_reserve_slot(i)) {
382 breakinfo[i].addr = 0;
383 return -1;
384 }
385 breakinfo[i].enabled = 1;
386
387 return 0;
388 }
389
390 /**
391 * kgdb_disable_hw_debug - Disable hardware debugging while we in kgdb.
392 * @regs: Current &struct pt_regs.
393 *
394 * This function will be called if the particular architecture must
395 * disable hardware debugging while it is processing gdb packets or
396 * handling exception.
397 */
398 static void kgdb_disable_hw_debug(struct pt_regs *regs)
399 {
400 int i;
401 int cpu = raw_smp_processor_id();
402 struct perf_event *bp;
403
404 /* Disable hardware debugging while we are in kgdb: */
405 set_debugreg(0UL, 7);
406 for (i = 0; i < HBP_NUM; i++) {
407 if (!breakinfo[i].enabled)
408 continue;
409 if (dbg_is_early) {
410 early_dr7 &= ~encode_dr7(i, breakinfo[i].len,
411 breakinfo[i].type);
412 continue;
413 }
414 bp = *per_cpu_ptr(breakinfo[i].pev, cpu);
415 if (bp->attr.disabled == 1)
416 continue;
417 arch_uninstall_hw_breakpoint(bp);
418 bp->attr.disabled = 1;
419 }
420 }
421
422 #ifdef CONFIG_SMP
423 /**
424 * kgdb_roundup_cpus - Get other CPUs into a holding pattern
425 * @flags: Current IRQ state
426 *
427 * On SMP systems, we need to get the attention of the other CPUs
428 * and get them be in a known state. This should do what is needed
429 * to get the other CPUs to call kgdb_wait(). Note that on some arches,
430 * the NMI approach is not used for rounding up all the CPUs. For example,
431 * in case of MIPS, smp_call_function() is used to roundup CPUs. In
432 * this case, we have to make sure that interrupts are enabled before
433 * calling smp_call_function(). The argument to this function is
434 * the flags that will be used when restoring the interrupts. There is
435 * local_irq_save() call before kgdb_roundup_cpus().
436 *
437 * On non-SMP systems, this is not called.
438 */
439 void kgdb_roundup_cpus(unsigned long flags)
440 {
441 apic->send_IPI_allbutself(APIC_DM_NMI);
442 }
443 #endif
444
445 /**
446 * kgdb_arch_handle_exception - Handle architecture specific GDB packets.
447 * @e_vector: The error vector of the exception that happened.
448 * @signo: The signal number of the exception that happened.
449 * @err_code: The error code of the exception that happened.
450 * @remcomInBuffer: The buffer of the packet we have read.
451 * @remcomOutBuffer: The buffer of %BUFMAX bytes to write a packet into.
452 * @linux_regs: The &struct pt_regs of the current process.
453 *
454 * This function MUST handle the 'c' and 's' command packets,
455 * as well packets to set / remove a hardware breakpoint, if used.
456 * If there are additional packets which the hardware needs to handle,
457 * they are handled here. The code should return -1 if it wants to
458 * process more packets, and a %0 or %1 if it wants to exit from the
459 * kgdb callback.
460 */
461 int kgdb_arch_handle_exception(int e_vector, int signo, int err_code,
462 char *remcomInBuffer, char *remcomOutBuffer,
463 struct pt_regs *linux_regs)
464 {
465 unsigned long addr;
466 char *ptr;
467
468 switch (remcomInBuffer[0]) {
469 case 'c':
470 case 's':
471 /* try to read optional parameter, pc unchanged if no parm */
472 ptr = &remcomInBuffer[1];
473 if (kgdb_hex2long(&ptr, &addr))
474 linux_regs->ip = addr;
475 case 'D':
476 case 'k':
477 /* clear the trace bit */
478 linux_regs->flags &= ~X86_EFLAGS_TF;
479 atomic_set(&kgdb_cpu_doing_single_step, -1);
480
481 /* set the trace bit if we're stepping */
482 if (remcomInBuffer[0] == 's') {
483 linux_regs->flags |= X86_EFLAGS_TF;
484 atomic_set(&kgdb_cpu_doing_single_step,
485 raw_smp_processor_id());
486 }
487
488 return 0;
489 }
490
491 /* this means that we do not want to exit from the handler: */
492 return -1;
493 }
494
495 static inline int
496 single_step_cont(struct pt_regs *regs, struct die_args *args)
497 {
498 /*
499 * Single step exception from kernel space to user space so
500 * eat the exception and continue the process:
501 */
502 printk(KERN_ERR "KGDB: trap/step from kernel to user space, "
503 "resuming...\n");
504 kgdb_arch_handle_exception(args->trapnr, args->signr,
505 args->err, "c", "", regs);
506 /*
507 * Reset the BS bit in dr6 (pointed by args->err) to
508 * denote completion of processing
509 */
510 (*(unsigned long *)ERR_PTR(args->err)) &= ~DR_STEP;
511
512 return NOTIFY_STOP;
513 }
514
515 static int was_in_debug_nmi[NR_CPUS];
516
517 static int kgdb_nmi_handler(unsigned int cmd, struct pt_regs *regs)
518 {
519 switch (cmd) {
520 case NMI_LOCAL:
521 if (atomic_read(&kgdb_active) != -1) {
522 /* KGDB CPU roundup */
523 kgdb_nmicallback(raw_smp_processor_id(), regs);
524 was_in_debug_nmi[raw_smp_processor_id()] = 1;
525 touch_nmi_watchdog();
526 return NMI_HANDLED;
527 }
528 break;
529
530 case NMI_UNKNOWN:
531 if (was_in_debug_nmi[raw_smp_processor_id()]) {
532 was_in_debug_nmi[raw_smp_processor_id()] = 0;
533 return NMI_HANDLED;
534 }
535 break;
536 default:
537 /* do nothing */
538 break;
539 }
540 return NMI_DONE;
541 }
542
543 static int __kgdb_notify(struct die_args *args, unsigned long cmd)
544 {
545 struct pt_regs *regs = args->regs;
546
547 switch (cmd) {
548 case DIE_DEBUG:
549 if (atomic_read(&kgdb_cpu_doing_single_step) != -1) {
550 if (user_mode(regs))
551 return single_step_cont(regs, args);
552 break;
553 } else if (test_thread_flag(TIF_SINGLESTEP))
554 /* This means a user thread is single stepping
555 * a system call which should be ignored
556 */
557 return NOTIFY_DONE;
558 /* fall through */
559 default:
560 if (user_mode(regs))
561 return NOTIFY_DONE;
562 }
563
564 if (kgdb_handle_exception(args->trapnr, args->signr, cmd, regs))
565 return NOTIFY_DONE;
566
567 /* Must touch watchdog before return to normal operation */
568 touch_nmi_watchdog();
569 return NOTIFY_STOP;
570 }
571
572 int kgdb_ll_trap(int cmd, const char *str,
573 struct pt_regs *regs, long err, int trap, int sig)
574 {
575 struct die_args args = {
576 .regs = regs,
577 .str = str,
578 .err = err,
579 .trapnr = trap,
580 .signr = sig,
581
582 };
583
584 if (!kgdb_io_module_registered)
585 return NOTIFY_DONE;
586
587 return __kgdb_notify(&args, cmd);
588 }
589
590 static int
591 kgdb_notify(struct notifier_block *self, unsigned long cmd, void *ptr)
592 {
593 unsigned long flags;
594 int ret;
595
596 local_irq_save(flags);
597 ret = __kgdb_notify(ptr, cmd);
598 local_irq_restore(flags);
599
600 return ret;
601 }
602
603 static struct notifier_block kgdb_notifier = {
604 .notifier_call = kgdb_notify,
605 };
606
607 /**
608 * kgdb_arch_init - Perform any architecture specific initalization.
609 *
610 * This function will handle the initalization of any architecture
611 * specific callbacks.
612 */
613 int kgdb_arch_init(void)
614 {
615 int retval;
616
617 retval = register_die_notifier(&kgdb_notifier);
618 if (retval)
619 goto out;
620
621 retval = register_nmi_handler(NMI_LOCAL, kgdb_nmi_handler,
622 0, "kgdb");
623 if (retval)
624 goto out1;
625
626 retval = register_nmi_handler(NMI_UNKNOWN, kgdb_nmi_handler,
627 0, "kgdb");
628
629 if (retval)
630 goto out2;
631
632 return retval;
633
634 out2:
635 unregister_nmi_handler(NMI_LOCAL, "kgdb");
636 out1:
637 unregister_die_notifier(&kgdb_notifier);
638 out:
639 return retval;
640 }
641
642 static void kgdb_hw_overflow_handler(struct perf_event *event,
643 struct perf_sample_data *data, struct pt_regs *regs)
644 {
645 struct task_struct *tsk = current;
646 int i;
647
648 for (i = 0; i < 4; i++)
649 if (breakinfo[i].enabled)
650 tsk->thread.debugreg6 |= (DR_TRAP0 << i);
651 }
652
653 void kgdb_arch_late(void)
654 {
655 int i, cpu;
656 struct perf_event_attr attr;
657 struct perf_event **pevent;
658
659 /*
660 * Pre-allocate the hw breakpoint structions in the non-atomic
661 * portion of kgdb because this operation requires mutexs to
662 * complete.
663 */
664 hw_breakpoint_init(&attr);
665 attr.bp_addr = (unsigned long)kgdb_arch_init;
666 attr.bp_len = HW_BREAKPOINT_LEN_1;
667 attr.bp_type = HW_BREAKPOINT_W;
668 attr.disabled = 1;
669 for (i = 0; i < HBP_NUM; i++) {
670 if (breakinfo[i].pev)
671 continue;
672 breakinfo[i].pev = register_wide_hw_breakpoint(&attr, NULL, NULL);
673 if (IS_ERR((void * __force)breakinfo[i].pev)) {
674 printk(KERN_ERR "kgdb: Could not allocate hw"
675 "breakpoints\nDisabling the kernel debugger\n");
676 breakinfo[i].pev = NULL;
677 kgdb_arch_exit();
678 return;
679 }
680 for_each_online_cpu(cpu) {
681 pevent = per_cpu_ptr(breakinfo[i].pev, cpu);
682 pevent[0]->hw.sample_period = 1;
683 pevent[0]->overflow_handler = kgdb_hw_overflow_handler;
684 if (pevent[0]->destroy != NULL) {
685 pevent[0]->destroy = NULL;
686 release_bp_slot(*pevent);
687 }
688 }
689 }
690 }
691
692 /**
693 * kgdb_arch_exit - Perform any architecture specific uninitalization.
694 *
695 * This function will handle the uninitalization of any architecture
696 * specific callbacks, for dynamic registration and unregistration.
697 */
698 void kgdb_arch_exit(void)
699 {
700 int i;
701 for (i = 0; i < 4; i++) {
702 if (breakinfo[i].pev) {
703 unregister_wide_hw_breakpoint(breakinfo[i].pev);
704 breakinfo[i].pev = NULL;
705 }
706 }
707 unregister_nmi_handler(NMI_UNKNOWN, "kgdb");
708 unregister_nmi_handler(NMI_LOCAL, "kgdb");
709 unregister_die_notifier(&kgdb_notifier);
710 }
711
712 /**
713 *
714 * kgdb_skipexception - Bail out of KGDB when we've been triggered.
715 * @exception: Exception vector number
716 * @regs: Current &struct pt_regs.
717 *
718 * On some architectures we need to skip a breakpoint exception when
719 * it occurs after a breakpoint has been removed.
720 *
721 * Skip an int3 exception when it occurs after a breakpoint has been
722 * removed. Backtrack eip by 1 since the int3 would have caused it to
723 * increment by 1.
724 */
725 int kgdb_skipexception(int exception, struct pt_regs *regs)
726 {
727 if (exception == 3 && kgdb_isremovedbreak(regs->ip - 1)) {
728 regs->ip -= 1;
729 return 1;
730 }
731 return 0;
732 }
733
734 unsigned long kgdb_arch_pc(int exception, struct pt_regs *regs)
735 {
736 if (exception == 3)
737 return instruction_pointer(regs) - 1;
738 return instruction_pointer(regs);
739 }
740
741 void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long ip)
742 {
743 regs->ip = ip;
744 }
745
746 int kgdb_arch_set_breakpoint(struct kgdb_bkpt *bpt)
747 {
748 int err;
749 #ifdef CONFIG_DEBUG_RODATA
750 char opc[BREAK_INSTR_SIZE];
751 #endif /* CONFIG_DEBUG_RODATA */
752
753 bpt->type = BP_BREAKPOINT;
754 err = probe_kernel_read(bpt->saved_instr, (char *)bpt->bpt_addr,
755 BREAK_INSTR_SIZE);
756 if (err)
757 return err;
758 err = probe_kernel_write((char *)bpt->bpt_addr,
759 arch_kgdb_ops.gdb_bpt_instr, BREAK_INSTR_SIZE);
760 #ifdef CONFIG_DEBUG_RODATA
761 if (!err)
762 return err;
763 /*
764 * It is safe to call text_poke() because normal kernel execution
765 * is stopped on all cores, so long as the text_mutex is not locked.
766 */
767 if (mutex_is_locked(&text_mutex))
768 return -EBUSY;
769 text_poke((void *)bpt->bpt_addr, arch_kgdb_ops.gdb_bpt_instr,
770 BREAK_INSTR_SIZE);
771 err = probe_kernel_read(opc, (char *)bpt->bpt_addr, BREAK_INSTR_SIZE);
772 if (err)
773 return err;
774 if (memcmp(opc, arch_kgdb_ops.gdb_bpt_instr, BREAK_INSTR_SIZE))
775 return -EINVAL;
776 bpt->type = BP_POKE_BREAKPOINT;
777 #endif /* CONFIG_DEBUG_RODATA */
778 return err;
779 }
780
781 int kgdb_arch_remove_breakpoint(struct kgdb_bkpt *bpt)
782 {
783 #ifdef CONFIG_DEBUG_RODATA
784 int err;
785 char opc[BREAK_INSTR_SIZE];
786
787 if (bpt->type != BP_POKE_BREAKPOINT)
788 goto knl_write;
789 /*
790 * It is safe to call text_poke() because normal kernel execution
791 * is stopped on all cores, so long as the text_mutex is not locked.
792 */
793 if (mutex_is_locked(&text_mutex))
794 goto knl_write;
795 text_poke((void *)bpt->bpt_addr, bpt->saved_instr, BREAK_INSTR_SIZE);
796 err = probe_kernel_read(opc, (char *)bpt->bpt_addr, BREAK_INSTR_SIZE);
797 if (err || memcmp(opc, bpt->saved_instr, BREAK_INSTR_SIZE))
798 goto knl_write;
799 return err;
800 knl_write:
801 #endif /* CONFIG_DEBUG_RODATA */
802 return probe_kernel_write((char *)bpt->bpt_addr,
803 (char *)bpt->saved_instr, BREAK_INSTR_SIZE);
804 }
805
806 struct kgdb_arch arch_kgdb_ops = {
807 /* Breakpoint instruction: */
808 .gdb_bpt_instr = { 0xcc },
809 .flags = KGDB_HW_BREAKPOINT,
810 .set_hw_breakpoint = kgdb_set_hw_break,
811 .remove_hw_breakpoint = kgdb_remove_hw_break,
812 .disable_hw_break = kgdb_disable_hw_debug,
813 .remove_all_hw_break = kgdb_remove_all_hw_break,
814 .correct_hw_break = kgdb_correct_hw_break,
815 };
kernel source for telekom puls (alcatel/mediatek)