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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 | ||
46 | #include <asm/debugreg.h> | |
47 | #include <asm/apicdef.h> | |
48 | #include <asm/system.h> | |
49 | ||
50 | #include <asm/apic.h> | |
51 | ||
52 | /* | |
53 | * Put the error code here just in case the user cares: | |
54 | */ | |
55 | static int gdb_x86errcode; | |
56 | ||
57 | /* | |
58 | * Likewise, the vector number here (since GDB only gets the signal | |
59 | * number through the usual means, and that's not very specific): | |
60 | */ | |
61 | static int gdb_x86vector = -1; | |
62 | ||
63 | /** | |
64 | * pt_regs_to_gdb_regs - Convert ptrace regs to GDB regs | |
65 | * @gdb_regs: A pointer to hold the registers in the order GDB wants. | |
66 | * @regs: The &struct pt_regs of the current process. | |
67 | * | |
68 | * Convert the pt_regs in @regs into the format for registers that | |
69 | * GDB expects, stored in @gdb_regs. | |
70 | */ | |
71 | void pt_regs_to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *regs) | |
72 | { | |
73 | #ifndef CONFIG_X86_32 | |
74 | u32 *gdb_regs32 = (u32 *)gdb_regs; | |
75 | #endif | |
76 | gdb_regs[GDB_AX] = regs->ax; | |
77 | gdb_regs[GDB_BX] = regs->bx; | |
78 | gdb_regs[GDB_CX] = regs->cx; | |
79 | gdb_regs[GDB_DX] = regs->dx; | |
80 | gdb_regs[GDB_SI] = regs->si; | |
81 | gdb_regs[GDB_DI] = regs->di; | |
82 | gdb_regs[GDB_BP] = regs->bp; | |
83 | gdb_regs[GDB_PC] = regs->ip; | |
84 | #ifdef CONFIG_X86_32 | |
85 | gdb_regs[GDB_PS] = regs->flags; | |
86 | gdb_regs[GDB_DS] = regs->ds; | |
87 | gdb_regs[GDB_ES] = regs->es; | |
88 | gdb_regs[GDB_CS] = regs->cs; | |
89 | gdb_regs[GDB_SS] = __KERNEL_DS; | |
90 | gdb_regs[GDB_FS] = 0xFFFF; | |
91 | gdb_regs[GDB_GS] = 0xFFFF; | |
92 | #else | |
93 | gdb_regs[GDB_R8] = regs->r8; | |
94 | gdb_regs[GDB_R9] = regs->r9; | |
95 | gdb_regs[GDB_R10] = regs->r10; | |
96 | gdb_regs[GDB_R11] = regs->r11; | |
97 | gdb_regs[GDB_R12] = regs->r12; | |
98 | gdb_regs[GDB_R13] = regs->r13; | |
99 | gdb_regs[GDB_R14] = regs->r14; | |
100 | gdb_regs[GDB_R15] = regs->r15; | |
101 | gdb_regs32[GDB_PS] = regs->flags; | |
102 | gdb_regs32[GDB_CS] = regs->cs; | |
103 | gdb_regs32[GDB_SS] = regs->ss; | |
104 | #endif | |
105 | gdb_regs[GDB_SP] = kernel_stack_pointer(regs); | |
106 | } | |
107 | ||
108 | /** | |
109 | * sleeping_thread_to_gdb_regs - Convert ptrace regs to GDB regs | |
110 | * @gdb_regs: A pointer to hold the registers in the order GDB wants. | |
111 | * @p: The &struct task_struct of the desired process. | |
112 | * | |
113 | * Convert the register values of the sleeping process in @p to | |
114 | * the format that GDB expects. | |
115 | * This function is called when kgdb does not have access to the | |
116 | * &struct pt_regs and therefore it should fill the gdb registers | |
117 | * @gdb_regs with what has been saved in &struct thread_struct | |
118 | * thread field during switch_to. | |
119 | */ | |
120 | void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p) | |
121 | { | |
122 | #ifndef CONFIG_X86_32 | |
123 | u32 *gdb_regs32 = (u32 *)gdb_regs; | |
124 | #endif | |
125 | gdb_regs[GDB_AX] = 0; | |
126 | gdb_regs[GDB_BX] = 0; | |
127 | gdb_regs[GDB_CX] = 0; | |
128 | gdb_regs[GDB_DX] = 0; | |
129 | gdb_regs[GDB_SI] = 0; | |
130 | gdb_regs[GDB_DI] = 0; | |
131 | gdb_regs[GDB_BP] = *(unsigned long *)p->thread.sp; | |
132 | #ifdef CONFIG_X86_32 | |
133 | gdb_regs[GDB_DS] = __KERNEL_DS; | |
134 | gdb_regs[GDB_ES] = __KERNEL_DS; | |
135 | gdb_regs[GDB_PS] = 0; | |
136 | gdb_regs[GDB_CS] = __KERNEL_CS; | |
137 | gdb_regs[GDB_PC] = p->thread.ip; | |
138 | gdb_regs[GDB_SS] = __KERNEL_DS; | |
139 | gdb_regs[GDB_FS] = 0xFFFF; | |
140 | gdb_regs[GDB_GS] = 0xFFFF; | |
141 | #else | |
142 | gdb_regs32[GDB_PS] = *(unsigned long *)(p->thread.sp + 8); | |
143 | gdb_regs32[GDB_CS] = __KERNEL_CS; | |
144 | gdb_regs32[GDB_SS] = __KERNEL_DS; | |
145 | gdb_regs[GDB_PC] = 0; | |
146 | gdb_regs[GDB_R8] = 0; | |
147 | gdb_regs[GDB_R9] = 0; | |
148 | gdb_regs[GDB_R10] = 0; | |
149 | gdb_regs[GDB_R11] = 0; | |
150 | gdb_regs[GDB_R12] = 0; | |
151 | gdb_regs[GDB_R13] = 0; | |
152 | gdb_regs[GDB_R14] = 0; | |
153 | gdb_regs[GDB_R15] = 0; | |
154 | #endif | |
155 | gdb_regs[GDB_SP] = p->thread.sp; | |
156 | } | |
157 | ||
158 | /** | |
159 | * gdb_regs_to_pt_regs - Convert GDB regs to ptrace regs. | |
160 | * @gdb_regs: A pointer to hold the registers we've received from GDB. | |
161 | * @regs: A pointer to a &struct pt_regs to hold these values in. | |
162 | * | |
163 | * Convert the GDB regs in @gdb_regs into the pt_regs, and store them | |
164 | * in @regs. | |
165 | */ | |
166 | void gdb_regs_to_pt_regs(unsigned long *gdb_regs, struct pt_regs *regs) | |
167 | { | |
168 | #ifndef CONFIG_X86_32 | |
169 | u32 *gdb_regs32 = (u32 *)gdb_regs; | |
170 | #endif | |
171 | regs->ax = gdb_regs[GDB_AX]; | |
172 | regs->bx = gdb_regs[GDB_BX]; | |
173 | regs->cx = gdb_regs[GDB_CX]; | |
174 | regs->dx = gdb_regs[GDB_DX]; | |
175 | regs->si = gdb_regs[GDB_SI]; | |
176 | regs->di = gdb_regs[GDB_DI]; | |
177 | regs->bp = gdb_regs[GDB_BP]; | |
178 | regs->ip = gdb_regs[GDB_PC]; | |
179 | #ifdef CONFIG_X86_32 | |
180 | regs->flags = gdb_regs[GDB_PS]; | |
181 | regs->ds = gdb_regs[GDB_DS]; | |
182 | regs->es = gdb_regs[GDB_ES]; | |
183 | regs->cs = gdb_regs[GDB_CS]; | |
184 | #else | |
185 | regs->r8 = gdb_regs[GDB_R8]; | |
186 | regs->r9 = gdb_regs[GDB_R9]; | |
187 | regs->r10 = gdb_regs[GDB_R10]; | |
188 | regs->r11 = gdb_regs[GDB_R11]; | |
189 | regs->r12 = gdb_regs[GDB_R12]; | |
190 | regs->r13 = gdb_regs[GDB_R13]; | |
191 | regs->r14 = gdb_regs[GDB_R14]; | |
192 | regs->r15 = gdb_regs[GDB_R15]; | |
193 | regs->flags = gdb_regs32[GDB_PS]; | |
194 | regs->cs = gdb_regs32[GDB_CS]; | |
195 | regs->ss = gdb_regs32[GDB_SS]; | |
196 | #endif | |
197 | } | |
198 | ||
199 | static struct hw_breakpoint { | |
200 | unsigned enabled; | |
201 | unsigned type; | |
202 | unsigned len; | |
203 | unsigned long addr; | |
204 | } breakinfo[4]; | |
205 | ||
206 | static void kgdb_correct_hw_break(void) | |
207 | { | |
208 | unsigned long dr7; | |
209 | int correctit = 0; | |
210 | int breakbit; | |
211 | int breakno; | |
212 | ||
213 | get_debugreg(dr7, 7); | |
214 | for (breakno = 0; breakno < 4; breakno++) { | |
215 | breakbit = 2 << (breakno << 1); | |
216 | if (!(dr7 & breakbit) && breakinfo[breakno].enabled) { | |
217 | correctit = 1; | |
218 | dr7 |= breakbit; | |
219 | dr7 &= ~(0xf0000 << (breakno << 2)); | |
220 | dr7 |= ((breakinfo[breakno].len << 2) | | |
221 | breakinfo[breakno].type) << | |
222 | ((breakno << 2) + 16); | |
223 | set_debugreg(breakinfo[breakno].addr, breakno); | |
224 | ||
225 | } else { | |
226 | if ((dr7 & breakbit) && !breakinfo[breakno].enabled) { | |
227 | correctit = 1; | |
228 | dr7 &= ~breakbit; | |
229 | dr7 &= ~(0xf0000 << (breakno << 2)); | |
230 | } | |
231 | } | |
232 | } | |
233 | if (correctit) | |
234 | set_debugreg(dr7, 7); | |
235 | } | |
236 | ||
237 | static int | |
238 | kgdb_remove_hw_break(unsigned long addr, int len, enum kgdb_bptype bptype) | |
239 | { | |
240 | int i; | |
241 | ||
242 | for (i = 0; i < 4; i++) | |
243 | if (breakinfo[i].addr == addr && breakinfo[i].enabled) | |
244 | break; | |
245 | if (i == 4) | |
246 | return -1; | |
247 | ||
248 | breakinfo[i].enabled = 0; | |
249 | ||
250 | return 0; | |
251 | } | |
252 | ||
253 | static void kgdb_remove_all_hw_break(void) | |
254 | { | |
255 | int i; | |
256 | ||
257 | for (i = 0; i < 4; i++) | |
258 | memset(&breakinfo[i], 0, sizeof(struct hw_breakpoint)); | |
259 | } | |
260 | ||
261 | static int | |
262 | kgdb_set_hw_break(unsigned long addr, int len, enum kgdb_bptype bptype) | |
263 | { | |
264 | unsigned type; | |
265 | int i; | |
266 | ||
267 | for (i = 0; i < 4; i++) | |
268 | if (!breakinfo[i].enabled) | |
269 | break; | |
270 | if (i == 4) | |
271 | return -1; | |
272 | ||
273 | switch (bptype) { | |
274 | case BP_HARDWARE_BREAKPOINT: | |
275 | type = 0; | |
276 | len = 1; | |
277 | break; | |
278 | case BP_WRITE_WATCHPOINT: | |
279 | type = 1; | |
280 | break; | |
281 | case BP_ACCESS_WATCHPOINT: | |
282 | type = 3; | |
283 | break; | |
284 | default: | |
285 | return -1; | |
286 | } | |
287 | ||
288 | if (len == 1 || len == 2 || len == 4) | |
289 | breakinfo[i].len = len - 1; | |
290 | else | |
291 | return -1; | |
292 | ||
293 | breakinfo[i].enabled = 1; | |
294 | breakinfo[i].addr = addr; | |
295 | breakinfo[i].type = type; | |
296 | ||
297 | return 0; | |
298 | } | |
299 | ||
300 | /** | |
301 | * kgdb_disable_hw_debug - Disable hardware debugging while we in kgdb. | |
302 | * @regs: Current &struct pt_regs. | |
303 | * | |
304 | * This function will be called if the particular architecture must | |
305 | * disable hardware debugging while it is processing gdb packets or | |
306 | * handling exception. | |
307 | */ | |
308 | void kgdb_disable_hw_debug(struct pt_regs *regs) | |
309 | { | |
310 | /* Disable hardware debugging while we are in kgdb: */ | |
311 | set_debugreg(0UL, 7); | |
312 | } | |
313 | ||
314 | /** | |
315 | * kgdb_post_primary_code - Save error vector/code numbers. | |
316 | * @regs: Original pt_regs. | |
317 | * @e_vector: Original error vector. | |
318 | * @err_code: Original error code. | |
319 | * | |
320 | * This is needed on architectures which support SMP and KGDB. | |
321 | * This function is called after all the slave cpus have been put | |
322 | * to a know spin state and the primary CPU has control over KGDB. | |
323 | */ | |
324 | void kgdb_post_primary_code(struct pt_regs *regs, int e_vector, int err_code) | |
325 | { | |
326 | /* primary processor is completely in the debugger */ | |
327 | gdb_x86vector = e_vector; | |
328 | gdb_x86errcode = err_code; | |
329 | } | |
330 | ||
331 | #ifdef CONFIG_SMP | |
332 | /** | |
333 | * kgdb_roundup_cpus - Get other CPUs into a holding pattern | |
334 | * @flags: Current IRQ state | |
335 | * | |
336 | * On SMP systems, we need to get the attention of the other CPUs | |
337 | * and get them be in a known state. This should do what is needed | |
338 | * to get the other CPUs to call kgdb_wait(). Note that on some arches, | |
339 | * the NMI approach is not used for rounding up all the CPUs. For example, | |
340 | * in case of MIPS, smp_call_function() is used to roundup CPUs. In | |
341 | * this case, we have to make sure that interrupts are enabled before | |
342 | * calling smp_call_function(). The argument to this function is | |
343 | * the flags that will be used when restoring the interrupts. There is | |
344 | * local_irq_save() call before kgdb_roundup_cpus(). | |
345 | * | |
346 | * On non-SMP systems, this is not called. | |
347 | */ | |
348 | void kgdb_roundup_cpus(unsigned long flags) | |
349 | { | |
350 | apic->send_IPI_allbutself(APIC_DM_NMI); | |
351 | } | |
352 | #endif | |
353 | ||
354 | /** | |
355 | * kgdb_arch_handle_exception - Handle architecture specific GDB packets. | |
356 | * @vector: The error vector of the exception that happened. | |
357 | * @signo: The signal number of the exception that happened. | |
358 | * @err_code: The error code of the exception that happened. | |
359 | * @remcom_in_buffer: The buffer of the packet we have read. | |
360 | * @remcom_out_buffer: The buffer of %BUFMAX bytes to write a packet into. | |
361 | * @regs: The &struct pt_regs of the current process. | |
362 | * | |
363 | * This function MUST handle the 'c' and 's' command packets, | |
364 | * as well packets to set / remove a hardware breakpoint, if used. | |
365 | * If there are additional packets which the hardware needs to handle, | |
366 | * they are handled here. The code should return -1 if it wants to | |
367 | * process more packets, and a %0 or %1 if it wants to exit from the | |
368 | * kgdb callback. | |
369 | */ | |
370 | int kgdb_arch_handle_exception(int e_vector, int signo, int err_code, | |
371 | char *remcomInBuffer, char *remcomOutBuffer, | |
372 | struct pt_regs *linux_regs) | |
373 | { | |
374 | unsigned long addr; | |
375 | unsigned long dr6; | |
376 | char *ptr; | |
377 | int newPC; | |
378 | ||
379 | switch (remcomInBuffer[0]) { | |
380 | case 'c': | |
381 | case 's': | |
382 | /* try to read optional parameter, pc unchanged if no parm */ | |
383 | ptr = &remcomInBuffer[1]; | |
384 | if (kgdb_hex2long(&ptr, &addr)) | |
385 | linux_regs->ip = addr; | |
386 | case 'D': | |
387 | case 'k': | |
388 | newPC = linux_regs->ip; | |
389 | ||
390 | /* clear the trace bit */ | |
391 | linux_regs->flags &= ~X86_EFLAGS_TF; | |
392 | atomic_set(&kgdb_cpu_doing_single_step, -1); | |
393 | ||
394 | /* set the trace bit if we're stepping */ | |
395 | if (remcomInBuffer[0] == 's') { | |
396 | linux_regs->flags |= X86_EFLAGS_TF; | |
397 | kgdb_single_step = 1; | |
398 | atomic_set(&kgdb_cpu_doing_single_step, | |
399 | raw_smp_processor_id()); | |
400 | } | |
401 | ||
402 | get_debugreg(dr6, 6); | |
403 | if (!(dr6 & 0x4000)) { | |
404 | int breakno; | |
405 | ||
406 | for (breakno = 0; breakno < 4; breakno++) { | |
407 | if (dr6 & (1 << breakno) && | |
408 | breakinfo[breakno].type == 0) { | |
409 | /* Set restore flag: */ | |
410 | linux_regs->flags |= X86_EFLAGS_RF; | |
411 | break; | |
412 | } | |
413 | } | |
414 | } | |
415 | set_debugreg(0UL, 6); | |
416 | kgdb_correct_hw_break(); | |
417 | ||
418 | return 0; | |
419 | } | |
420 | ||
421 | /* this means that we do not want to exit from the handler: */ | |
422 | return -1; | |
423 | } | |
424 | ||
425 | static inline int | |
426 | single_step_cont(struct pt_regs *regs, struct die_args *args) | |
427 | { | |
428 | /* | |
429 | * Single step exception from kernel space to user space so | |
430 | * eat the exception and continue the process: | |
431 | */ | |
432 | printk(KERN_ERR "KGDB: trap/step from kernel to user space, " | |
433 | "resuming...\n"); | |
434 | kgdb_arch_handle_exception(args->trapnr, args->signr, | |
435 | args->err, "c", "", regs); | |
436 | /* | |
437 | * Reset the BS bit in dr6 (pointed by args->err) to | |
438 | * denote completion of processing | |
439 | */ | |
440 | (*(unsigned long *)ERR_PTR(args->err)) &= ~DR_STEP; | |
441 | ||
442 | return NOTIFY_STOP; | |
443 | } | |
444 | ||
445 | static int was_in_debug_nmi[NR_CPUS]; | |
446 | ||
447 | static int __kgdb_notify(struct die_args *args, unsigned long cmd) | |
448 | { | |
449 | struct pt_regs *regs = args->regs; | |
450 | ||
451 | switch (cmd) { | |
452 | case DIE_NMI: | |
453 | if (atomic_read(&kgdb_active) != -1) { | |
454 | /* KGDB CPU roundup */ | |
455 | kgdb_nmicallback(raw_smp_processor_id(), regs); | |
456 | was_in_debug_nmi[raw_smp_processor_id()] = 1; | |
457 | touch_nmi_watchdog(); | |
458 | return NOTIFY_STOP; | |
459 | } | |
460 | return NOTIFY_DONE; | |
461 | ||
462 | case DIE_NMI_IPI: | |
463 | /* Just ignore, we will handle the roundup on DIE_NMI. */ | |
464 | return NOTIFY_DONE; | |
465 | ||
466 | case DIE_NMIUNKNOWN: | |
467 | if (was_in_debug_nmi[raw_smp_processor_id()]) { | |
468 | was_in_debug_nmi[raw_smp_processor_id()] = 0; | |
469 | return NOTIFY_STOP; | |
470 | } | |
471 | return NOTIFY_DONE; | |
472 | ||
473 | case DIE_NMIWATCHDOG: | |
474 | if (atomic_read(&kgdb_active) != -1) { | |
475 | /* KGDB CPU roundup: */ | |
476 | kgdb_nmicallback(raw_smp_processor_id(), regs); | |
477 | return NOTIFY_STOP; | |
478 | } | |
479 | /* Enter debugger: */ | |
480 | break; | |
481 | ||
482 | case DIE_DEBUG: | |
483 | if (atomic_read(&kgdb_cpu_doing_single_step) == | |
484 | raw_smp_processor_id()) { | |
485 | if (user_mode(regs)) | |
486 | return single_step_cont(regs, args); | |
487 | break; | |
488 | } else if (test_thread_flag(TIF_SINGLESTEP)) | |
489 | /* This means a user thread is single stepping | |
490 | * a system call which should be ignored | |
491 | */ | |
492 | return NOTIFY_DONE; | |
493 | /* fall through */ | |
494 | default: | |
495 | if (user_mode(regs)) | |
496 | return NOTIFY_DONE; | |
497 | } | |
498 | ||
499 | if (kgdb_handle_exception(args->trapnr, args->signr, args->err, regs)) | |
500 | return NOTIFY_DONE; | |
501 | ||
502 | /* Must touch watchdog before return to normal operation */ | |
503 | touch_nmi_watchdog(); | |
504 | return NOTIFY_STOP; | |
505 | } | |
506 | ||
507 | static int | |
508 | kgdb_notify(struct notifier_block *self, unsigned long cmd, void *ptr) | |
509 | { | |
510 | unsigned long flags; | |
511 | int ret; | |
512 | ||
513 | local_irq_save(flags); | |
514 | ret = __kgdb_notify(ptr, cmd); | |
515 | local_irq_restore(flags); | |
516 | ||
517 | return ret; | |
518 | } | |
519 | ||
520 | static struct notifier_block kgdb_notifier = { | |
521 | .notifier_call = kgdb_notify, | |
522 | ||
523 | /* | |
524 | * Lowest-prio notifier priority, we want to be notified last: | |
525 | */ | |
526 | .priority = -INT_MAX, | |
527 | }; | |
528 | ||
529 | /** | |
530 | * kgdb_arch_init - Perform any architecture specific initalization. | |
531 | * | |
532 | * This function will handle the initalization of any architecture | |
533 | * specific callbacks. | |
534 | */ | |
535 | int kgdb_arch_init(void) | |
536 | { | |
537 | return register_die_notifier(&kgdb_notifier); | |
538 | } | |
539 | ||
540 | /** | |
541 | * kgdb_arch_exit - Perform any architecture specific uninitalization. | |
542 | * | |
543 | * This function will handle the uninitalization of any architecture | |
544 | * specific callbacks, for dynamic registration and unregistration. | |
545 | */ | |
546 | void kgdb_arch_exit(void) | |
547 | { | |
548 | unregister_die_notifier(&kgdb_notifier); | |
549 | } | |
550 | ||
551 | /** | |
552 | * | |
553 | * kgdb_skipexception - Bail out of KGDB when we've been triggered. | |
554 | * @exception: Exception vector number | |
555 | * @regs: Current &struct pt_regs. | |
556 | * | |
557 | * On some architectures we need to skip a breakpoint exception when | |
558 | * it occurs after a breakpoint has been removed. | |
559 | * | |
560 | * Skip an int3 exception when it occurs after a breakpoint has been | |
561 | * removed. Backtrack eip by 1 since the int3 would have caused it to | |
562 | * increment by 1. | |
563 | */ | |
564 | int kgdb_skipexception(int exception, struct pt_regs *regs) | |
565 | { | |
566 | if (exception == 3 && kgdb_isremovedbreak(regs->ip - 1)) { | |
567 | regs->ip -= 1; | |
568 | return 1; | |
569 | } | |
570 | return 0; | |
571 | } | |
572 | ||
573 | unsigned long kgdb_arch_pc(int exception, struct pt_regs *regs) | |
574 | { | |
575 | if (exception == 3) | |
576 | return instruction_pointer(regs) - 1; | |
577 | return instruction_pointer(regs); | |
578 | } | |
579 | ||
580 | struct kgdb_arch arch_kgdb_ops = { | |
581 | /* Breakpoint instruction: */ | |
582 | .gdb_bpt_instr = { 0xcc }, | |
583 | .flags = KGDB_HW_BREAKPOINT, | |
584 | .set_hw_breakpoint = kgdb_set_hw_break, | |
585 | .remove_hw_breakpoint = kgdb_remove_hw_break, | |
586 | .remove_all_hw_break = kgdb_remove_all_hw_break, | |
587 | .correct_hw_break = kgdb_correct_hw_break, | |
588 | }; |