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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> | |
50 | ||
7b6aa335 | 51 | #include <asm/apic.h> |
82da3ff8 IM |
52 | |
53 | /* | |
54 | * Put the error code here just in case the user cares: | |
55 | */ | |
56 | static int gdb_x86errcode; | |
57 | ||
58 | /* | |
59 | * Likewise, the vector number here (since GDB only gets the signal | |
60 | * number through the usual means, and that's not very specific): | |
61 | */ | |
62 | static int gdb_x86vector = -1; | |
63 | ||
64 | /** | |
65 | * pt_regs_to_gdb_regs - Convert ptrace regs to GDB regs | |
66 | * @gdb_regs: A pointer to hold the registers in the order GDB wants. | |
67 | * @regs: The &struct pt_regs of the current process. | |
68 | * | |
69 | * Convert the pt_regs in @regs into the format for registers that | |
70 | * GDB expects, stored in @gdb_regs. | |
71 | */ | |
72 | void pt_regs_to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *regs) | |
73 | { | |
703a1edc JW |
74 | #ifndef CONFIG_X86_32 |
75 | u32 *gdb_regs32 = (u32 *)gdb_regs; | |
76 | #endif | |
82da3ff8 IM |
77 | gdb_regs[GDB_AX] = regs->ax; |
78 | gdb_regs[GDB_BX] = regs->bx; | |
79 | gdb_regs[GDB_CX] = regs->cx; | |
80 | gdb_regs[GDB_DX] = regs->dx; | |
81 | gdb_regs[GDB_SI] = regs->si; | |
82 | gdb_regs[GDB_DI] = regs->di; | |
83 | gdb_regs[GDB_BP] = regs->bp; | |
82da3ff8 IM |
84 | gdb_regs[GDB_PC] = regs->ip; |
85 | #ifdef CONFIG_X86_32 | |
703a1edc | 86 | gdb_regs[GDB_PS] = regs->flags; |
82da3ff8 IM |
87 | gdb_regs[GDB_DS] = regs->ds; |
88 | gdb_regs[GDB_ES] = regs->es; | |
89 | gdb_regs[GDB_CS] = regs->cs; | |
82da3ff8 IM |
90 | gdb_regs[GDB_FS] = 0xFFFF; |
91 | gdb_regs[GDB_GS] = 0xFFFF; | |
cf6f196d JW |
92 | if (user_mode_vm(regs)) { |
93 | gdb_regs[GDB_SS] = regs->ss; | |
94 | gdb_regs[GDB_SP] = regs->sp; | |
95 | } else { | |
96 | gdb_regs[GDB_SS] = __KERNEL_DS; | |
97 | gdb_regs[GDB_SP] = kernel_stack_pointer(regs); | |
98 | } | |
82da3ff8 IM |
99 | #else |
100 | gdb_regs[GDB_R8] = regs->r8; | |
101 | gdb_regs[GDB_R9] = regs->r9; | |
102 | gdb_regs[GDB_R10] = regs->r10; | |
103 | gdb_regs[GDB_R11] = regs->r11; | |
104 | gdb_regs[GDB_R12] = regs->r12; | |
105 | gdb_regs[GDB_R13] = regs->r13; | |
106 | gdb_regs[GDB_R14] = regs->r14; | |
107 | gdb_regs[GDB_R15] = regs->r15; | |
703a1edc JW |
108 | gdb_regs32[GDB_PS] = regs->flags; |
109 | gdb_regs32[GDB_CS] = regs->cs; | |
110 | gdb_regs32[GDB_SS] = regs->ss; | |
5ca6c0ca | 111 | gdb_regs[GDB_SP] = kernel_stack_pointer(regs); |
cf6f196d | 112 | #endif |
82da3ff8 IM |
113 | } |
114 | ||
115 | /** | |
116 | * sleeping_thread_to_gdb_regs - Convert ptrace regs to GDB regs | |
117 | * @gdb_regs: A pointer to hold the registers in the order GDB wants. | |
118 | * @p: The &struct task_struct of the desired process. | |
119 | * | |
120 | * Convert the register values of the sleeping process in @p to | |
121 | * the format that GDB expects. | |
122 | * This function is called when kgdb does not have access to the | |
123 | * &struct pt_regs and therefore it should fill the gdb registers | |
124 | * @gdb_regs with what has been saved in &struct thread_struct | |
125 | * thread field during switch_to. | |
126 | */ | |
127 | void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p) | |
128 | { | |
703a1edc JW |
129 | #ifndef CONFIG_X86_32 |
130 | u32 *gdb_regs32 = (u32 *)gdb_regs; | |
131 | #endif | |
82da3ff8 IM |
132 | gdb_regs[GDB_AX] = 0; |
133 | gdb_regs[GDB_BX] = 0; | |
134 | gdb_regs[GDB_CX] = 0; | |
135 | gdb_regs[GDB_DX] = 0; | |
136 | gdb_regs[GDB_SI] = 0; | |
137 | gdb_regs[GDB_DI] = 0; | |
138 | gdb_regs[GDB_BP] = *(unsigned long *)p->thread.sp; | |
139 | #ifdef CONFIG_X86_32 | |
140 | gdb_regs[GDB_DS] = __KERNEL_DS; | |
141 | gdb_regs[GDB_ES] = __KERNEL_DS; | |
142 | gdb_regs[GDB_PS] = 0; | |
143 | gdb_regs[GDB_CS] = __KERNEL_CS; | |
144 | gdb_regs[GDB_PC] = p->thread.ip; | |
145 | gdb_regs[GDB_SS] = __KERNEL_DS; | |
146 | gdb_regs[GDB_FS] = 0xFFFF; | |
147 | gdb_regs[GDB_GS] = 0xFFFF; | |
148 | #else | |
703a1edc JW |
149 | gdb_regs32[GDB_PS] = *(unsigned long *)(p->thread.sp + 8); |
150 | gdb_regs32[GDB_CS] = __KERNEL_CS; | |
151 | gdb_regs32[GDB_SS] = __KERNEL_DS; | |
0c23590f | 152 | gdb_regs[GDB_PC] = 0; |
82da3ff8 IM |
153 | gdb_regs[GDB_R8] = 0; |
154 | gdb_regs[GDB_R9] = 0; | |
155 | gdb_regs[GDB_R10] = 0; | |
156 | gdb_regs[GDB_R11] = 0; | |
157 | gdb_regs[GDB_R12] = 0; | |
158 | gdb_regs[GDB_R13] = 0; | |
159 | gdb_regs[GDB_R14] = 0; | |
160 | gdb_regs[GDB_R15] = 0; | |
161 | #endif | |
162 | gdb_regs[GDB_SP] = p->thread.sp; | |
163 | } | |
164 | ||
165 | /** | |
166 | * gdb_regs_to_pt_regs - Convert GDB regs to ptrace regs. | |
167 | * @gdb_regs: A pointer to hold the registers we've received from GDB. | |
168 | * @regs: A pointer to a &struct pt_regs to hold these values in. | |
169 | * | |
170 | * Convert the GDB regs in @gdb_regs into the pt_regs, and store them | |
171 | * in @regs. | |
172 | */ | |
173 | void gdb_regs_to_pt_regs(unsigned long *gdb_regs, struct pt_regs *regs) | |
174 | { | |
703a1edc JW |
175 | #ifndef CONFIG_X86_32 |
176 | u32 *gdb_regs32 = (u32 *)gdb_regs; | |
177 | #endif | |
82da3ff8 IM |
178 | regs->ax = gdb_regs[GDB_AX]; |
179 | regs->bx = gdb_regs[GDB_BX]; | |
180 | regs->cx = gdb_regs[GDB_CX]; | |
181 | regs->dx = gdb_regs[GDB_DX]; | |
182 | regs->si = gdb_regs[GDB_SI]; | |
183 | regs->di = gdb_regs[GDB_DI]; | |
184 | regs->bp = gdb_regs[GDB_BP]; | |
82da3ff8 IM |
185 | regs->ip = gdb_regs[GDB_PC]; |
186 | #ifdef CONFIG_X86_32 | |
703a1edc | 187 | regs->flags = gdb_regs[GDB_PS]; |
82da3ff8 IM |
188 | regs->ds = gdb_regs[GDB_DS]; |
189 | regs->es = gdb_regs[GDB_ES]; | |
190 | regs->cs = gdb_regs[GDB_CS]; | |
191 | #else | |
192 | regs->r8 = gdb_regs[GDB_R8]; | |
193 | regs->r9 = gdb_regs[GDB_R9]; | |
194 | regs->r10 = gdb_regs[GDB_R10]; | |
195 | regs->r11 = gdb_regs[GDB_R11]; | |
196 | regs->r12 = gdb_regs[GDB_R12]; | |
197 | regs->r13 = gdb_regs[GDB_R13]; | |
198 | regs->r14 = gdb_regs[GDB_R14]; | |
199 | regs->r15 = gdb_regs[GDB_R15]; | |
703a1edc JW |
200 | regs->flags = gdb_regs32[GDB_PS]; |
201 | regs->cs = gdb_regs32[GDB_CS]; | |
202 | regs->ss = gdb_regs32[GDB_SS]; | |
82da3ff8 IM |
203 | #endif |
204 | } | |
205 | ||
64e9ee30 JW |
206 | static struct hw_breakpoint { |
207 | unsigned enabled; | |
64e9ee30 | 208 | unsigned long addr; |
cc096749 JW |
209 | int len; |
210 | int type; | |
211 | struct perf_event **pev; | |
64e9ee30 JW |
212 | } breakinfo[4]; |
213 | ||
214 | static void kgdb_correct_hw_break(void) | |
215 | { | |
64e9ee30 JW |
216 | int breakno; |
217 | ||
64e9ee30 | 218 | for (breakno = 0; breakno < 4; breakno++) { |
cc096749 JW |
219 | struct perf_event *bp; |
220 | struct arch_hw_breakpoint *info; | |
221 | int val; | |
222 | int cpu = raw_smp_processor_id(); | |
223 | if (!breakinfo[breakno].enabled) | |
224 | continue; | |
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; | |
64e9ee30 | 238 | } |
cc096749 | 239 | hw_breakpoint_restore(); |
64e9ee30 JW |
240 | } |
241 | ||
5352ae63 JW |
242 | static int hw_break_reserve_slot(int breakno) |
243 | { | |
244 | int cpu; | |
245 | int cnt = 0; | |
246 | struct perf_event **pevent; | |
247 | ||
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 | ||
257 | fail: | |
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 | ||
268 | static int hw_break_release_slot(int breakno) | |
269 | { | |
270 | struct perf_event **pevent; | |
271 | int cpu; | |
272 | ||
273 | for_each_online_cpu(cpu) { | |
274 | pevent = per_cpu_ptr(breakinfo[breakno].pev, cpu); | |
275 | if (dbg_release_bp_slot(*pevent)) | |
276 | /* | |
277 | * The debugger is responisble for handing the retry on | |
278 | * remove failure. | |
279 | */ | |
280 | return -1; | |
281 | } | |
282 | return 0; | |
283 | } | |
284 | ||
64e9ee30 JW |
285 | static int |
286 | kgdb_remove_hw_break(unsigned long addr, int len, enum kgdb_bptype bptype) | |
287 | { | |
288 | int i; | |
289 | ||
290 | for (i = 0; i < 4; i++) | |
291 | if (breakinfo[i].addr == addr && breakinfo[i].enabled) | |
292 | break; | |
293 | if (i == 4) | |
294 | return -1; | |
295 | ||
5352ae63 JW |
296 | if (hw_break_release_slot(i)) { |
297 | printk(KERN_ERR "Cannot remove hw breakpoint at %lx\n", addr); | |
298 | return -1; | |
299 | } | |
64e9ee30 JW |
300 | breakinfo[i].enabled = 0; |
301 | ||
302 | return 0; | |
303 | } | |
304 | ||
305 | static void kgdb_remove_all_hw_break(void) | |
306 | { | |
307 | int i; | |
cc096749 JW |
308 | int cpu = raw_smp_processor_id(); |
309 | struct perf_event *bp; | |
64e9ee30 | 310 | |
cc096749 JW |
311 | for (i = 0; i < 4; i++) { |
312 | if (!breakinfo[i].enabled) | |
313 | continue; | |
314 | bp = *per_cpu_ptr(breakinfo[i].pev, cpu); | |
315 | if (bp->attr.disabled == 1) | |
316 | continue; | |
317 | arch_uninstall_hw_breakpoint(bp); | |
318 | bp->attr.disabled = 1; | |
319 | } | |
64e9ee30 JW |
320 | } |
321 | ||
322 | static int | |
323 | kgdb_set_hw_break(unsigned long addr, int len, enum kgdb_bptype bptype) | |
324 | { | |
64e9ee30 JW |
325 | int i; |
326 | ||
327 | for (i = 0; i < 4; i++) | |
328 | if (!breakinfo[i].enabled) | |
329 | break; | |
330 | if (i == 4) | |
331 | return -1; | |
332 | ||
333 | switch (bptype) { | |
334 | case BP_HARDWARE_BREAKPOINT: | |
cc096749 JW |
335 | len = 1; |
336 | breakinfo[i].type = X86_BREAKPOINT_EXECUTE; | |
64e9ee30 JW |
337 | break; |
338 | case BP_WRITE_WATCHPOINT: | |
cc096749 | 339 | breakinfo[i].type = X86_BREAKPOINT_WRITE; |
64e9ee30 JW |
340 | break; |
341 | case BP_ACCESS_WATCHPOINT: | |
cc096749 | 342 | breakinfo[i].type = X86_BREAKPOINT_RW; |
64e9ee30 JW |
343 | break; |
344 | default: | |
345 | return -1; | |
346 | } | |
cc096749 JW |
347 | switch (len) { |
348 | case 1: | |
349 | breakinfo[i].len = X86_BREAKPOINT_LEN_1; | |
350 | break; | |
351 | case 2: | |
352 | breakinfo[i].len = X86_BREAKPOINT_LEN_2; | |
353 | break; | |
354 | case 4: | |
355 | breakinfo[i].len = X86_BREAKPOINT_LEN_4; | |
356 | break; | |
357 | #ifdef CONFIG_X86_64 | |
358 | case 8: | |
359 | breakinfo[i].len = X86_BREAKPOINT_LEN_8; | |
360 | break; | |
361 | #endif | |
362 | default: | |
64e9ee30 | 363 | return -1; |
cc096749 | 364 | } |
64e9ee30 | 365 | breakinfo[i].addr = addr; |
5352ae63 JW |
366 | if (hw_break_reserve_slot(i)) { |
367 | breakinfo[i].addr = 0; | |
368 | return -1; | |
369 | } | |
cc096749 | 370 | breakinfo[i].enabled = 1; |
64e9ee30 JW |
371 | |
372 | return 0; | |
373 | } | |
374 | ||
375 | /** | |
376 | * kgdb_disable_hw_debug - Disable hardware debugging while we in kgdb. | |
377 | * @regs: Current &struct pt_regs. | |
378 | * | |
379 | * This function will be called if the particular architecture must | |
380 | * disable hardware debugging while it is processing gdb packets or | |
381 | * handling exception. | |
382 | */ | |
383 | void kgdb_disable_hw_debug(struct pt_regs *regs) | |
384 | { | |
cc096749 JW |
385 | int i; |
386 | int cpu = raw_smp_processor_id(); | |
387 | struct perf_event *bp; | |
388 | ||
64e9ee30 JW |
389 | /* Disable hardware debugging while we are in kgdb: */ |
390 | set_debugreg(0UL, 7); | |
cc096749 JW |
391 | for (i = 0; i < 4; i++) { |
392 | if (!breakinfo[i].enabled) | |
393 | continue; | |
394 | bp = *per_cpu_ptr(breakinfo[i].pev, cpu); | |
395 | if (bp->attr.disabled == 1) | |
396 | continue; | |
397 | arch_uninstall_hw_breakpoint(bp); | |
398 | bp->attr.disabled = 1; | |
399 | } | |
64e9ee30 JW |
400 | } |
401 | ||
82da3ff8 IM |
402 | /** |
403 | * kgdb_post_primary_code - Save error vector/code numbers. | |
404 | * @regs: Original pt_regs. | |
405 | * @e_vector: Original error vector. | |
406 | * @err_code: Original error code. | |
407 | * | |
408 | * This is needed on architectures which support SMP and KGDB. | |
409 | * This function is called after all the slave cpus have been put | |
410 | * to a know spin state and the primary CPU has control over KGDB. | |
411 | */ | |
412 | void kgdb_post_primary_code(struct pt_regs *regs, int e_vector, int err_code) | |
413 | { | |
414 | /* primary processor is completely in the debugger */ | |
415 | gdb_x86vector = e_vector; | |
416 | gdb_x86errcode = err_code; | |
417 | } | |
418 | ||
419 | #ifdef CONFIG_SMP | |
420 | /** | |
421 | * kgdb_roundup_cpus - Get other CPUs into a holding pattern | |
422 | * @flags: Current IRQ state | |
423 | * | |
424 | * On SMP systems, we need to get the attention of the other CPUs | |
425 | * and get them be in a known state. This should do what is needed | |
426 | * to get the other CPUs to call kgdb_wait(). Note that on some arches, | |
427 | * the NMI approach is not used for rounding up all the CPUs. For example, | |
428 | * in case of MIPS, smp_call_function() is used to roundup CPUs. In | |
429 | * this case, we have to make sure that interrupts are enabled before | |
430 | * calling smp_call_function(). The argument to this function is | |
431 | * the flags that will be used when restoring the interrupts. There is | |
432 | * local_irq_save() call before kgdb_roundup_cpus(). | |
433 | * | |
434 | * On non-SMP systems, this is not called. | |
435 | */ | |
436 | void kgdb_roundup_cpus(unsigned long flags) | |
437 | { | |
dac5f412 | 438 | apic->send_IPI_allbutself(APIC_DM_NMI); |
82da3ff8 IM |
439 | } |
440 | #endif | |
441 | ||
442 | /** | |
443 | * kgdb_arch_handle_exception - Handle architecture specific GDB packets. | |
444 | * @vector: The error vector of the exception that happened. | |
445 | * @signo: The signal number of the exception that happened. | |
446 | * @err_code: The error code of the exception that happened. | |
447 | * @remcom_in_buffer: The buffer of the packet we have read. | |
448 | * @remcom_out_buffer: The buffer of %BUFMAX bytes to write a packet into. | |
449 | * @regs: The &struct pt_regs of the current process. | |
450 | * | |
451 | * This function MUST handle the 'c' and 's' command packets, | |
452 | * as well packets to set / remove a hardware breakpoint, if used. | |
453 | * If there are additional packets which the hardware needs to handle, | |
454 | * they are handled here. The code should return -1 if it wants to | |
455 | * process more packets, and a %0 or %1 if it wants to exit from the | |
456 | * kgdb callback. | |
457 | */ | |
458 | int kgdb_arch_handle_exception(int e_vector, int signo, int err_code, | |
459 | char *remcomInBuffer, char *remcomOutBuffer, | |
460 | struct pt_regs *linux_regs) | |
461 | { | |
462 | unsigned long addr; | |
463 | char *ptr; | |
464 | int newPC; | |
465 | ||
466 | switch (remcomInBuffer[0]) { | |
467 | case 'c': | |
468 | case 's': | |
469 | /* try to read optional parameter, pc unchanged if no parm */ | |
470 | ptr = &remcomInBuffer[1]; | |
471 | if (kgdb_hex2long(&ptr, &addr)) | |
472 | linux_regs->ip = addr; | |
737a460f JW |
473 | case 'D': |
474 | case 'k': | |
82da3ff8 IM |
475 | newPC = linux_regs->ip; |
476 | ||
477 | /* clear the trace bit */ | |
fda31d7d | 478 | linux_regs->flags &= ~X86_EFLAGS_TF; |
82da3ff8 IM |
479 | atomic_set(&kgdb_cpu_doing_single_step, -1); |
480 | ||
481 | /* set the trace bit if we're stepping */ | |
482 | if (remcomInBuffer[0] == 's') { | |
fda31d7d | 483 | linux_regs->flags |= X86_EFLAGS_TF; |
d7161a65 JW |
484 | atomic_set(&kgdb_cpu_doing_single_step, |
485 | raw_smp_processor_id()); | |
82da3ff8 IM |
486 | } |
487 | ||
64e9ee30 JW |
488 | kgdb_correct_hw_break(); |
489 | ||
82da3ff8 IM |
490 | return 0; |
491 | } | |
492 | ||
493 | /* this means that we do not want to exit from the handler: */ | |
494 | return -1; | |
495 | } | |
496 | ||
497 | static inline int | |
498 | single_step_cont(struct pt_regs *regs, struct die_args *args) | |
499 | { | |
500 | /* | |
501 | * Single step exception from kernel space to user space so | |
502 | * eat the exception and continue the process: | |
503 | */ | |
504 | printk(KERN_ERR "KGDB: trap/step from kernel to user space, " | |
505 | "resuming...\n"); | |
506 | kgdb_arch_handle_exception(args->trapnr, args->signr, | |
507 | args->err, "c", "", regs); | |
62edab90 P |
508 | /* |
509 | * Reset the BS bit in dr6 (pointed by args->err) to | |
510 | * denote completion of processing | |
511 | */ | |
512 | (*(unsigned long *)ERR_PTR(args->err)) &= ~DR_STEP; | |
82da3ff8 IM |
513 | |
514 | return NOTIFY_STOP; | |
515 | } | |
516 | ||
d3597524 JW |
517 | static int was_in_debug_nmi[NR_CPUS]; |
518 | ||
82da3ff8 IM |
519 | static int __kgdb_notify(struct die_args *args, unsigned long cmd) |
520 | { | |
521 | struct pt_regs *regs = args->regs; | |
522 | ||
523 | switch (cmd) { | |
524 | case DIE_NMI: | |
525 | if (atomic_read(&kgdb_active) != -1) { | |
526 | /* KGDB CPU roundup */ | |
527 | kgdb_nmicallback(raw_smp_processor_id(), regs); | |
d3597524 JW |
528 | was_in_debug_nmi[raw_smp_processor_id()] = 1; |
529 | touch_nmi_watchdog(); | |
82da3ff8 IM |
530 | return NOTIFY_STOP; |
531 | } | |
532 | return NOTIFY_DONE; | |
533 | ||
534 | case DIE_NMI_IPI: | |
e85ceae9 | 535 | /* Just ignore, we will handle the roundup on DIE_NMI. */ |
d3597524 JW |
536 | return NOTIFY_DONE; |
537 | ||
538 | case DIE_NMIUNKNOWN: | |
539 | if (was_in_debug_nmi[raw_smp_processor_id()]) { | |
540 | was_in_debug_nmi[raw_smp_processor_id()] = 0; | |
82da3ff8 IM |
541 | return NOTIFY_STOP; |
542 | } | |
543 | return NOTIFY_DONE; | |
544 | ||
545 | case DIE_NMIWATCHDOG: | |
546 | if (atomic_read(&kgdb_active) != -1) { | |
547 | /* KGDB CPU roundup: */ | |
548 | kgdb_nmicallback(raw_smp_processor_id(), regs); | |
549 | return NOTIFY_STOP; | |
550 | } | |
551 | /* Enter debugger: */ | |
552 | break; | |
553 | ||
554 | case DIE_DEBUG: | |
cc096749 | 555 | if (atomic_read(&kgdb_cpu_doing_single_step) != -1) { |
d7161a65 JW |
556 | if (user_mode(regs)) |
557 | return single_step_cont(regs, args); | |
558 | break; | |
559 | } else if (test_thread_flag(TIF_SINGLESTEP)) | |
560 | /* This means a user thread is single stepping | |
561 | * a system call which should be ignored | |
562 | */ | |
563 | return NOTIFY_DONE; | |
82da3ff8 IM |
564 | /* fall through */ |
565 | default: | |
566 | if (user_mode(regs)) | |
567 | return NOTIFY_DONE; | |
568 | } | |
569 | ||
570 | if (kgdb_handle_exception(args->trapnr, args->signr, args->err, regs)) | |
571 | return NOTIFY_DONE; | |
572 | ||
737a460f JW |
573 | /* Must touch watchdog before return to normal operation */ |
574 | touch_nmi_watchdog(); | |
82da3ff8 IM |
575 | return NOTIFY_STOP; |
576 | } | |
577 | ||
578 | static int | |
579 | kgdb_notify(struct notifier_block *self, unsigned long cmd, void *ptr) | |
580 | { | |
581 | unsigned long flags; | |
582 | int ret; | |
583 | ||
584 | local_irq_save(flags); | |
585 | ret = __kgdb_notify(ptr, cmd); | |
586 | local_irq_restore(flags); | |
587 | ||
588 | return ret; | |
589 | } | |
590 | ||
591 | static struct notifier_block kgdb_notifier = { | |
592 | .notifier_call = kgdb_notify, | |
593 | ||
594 | /* | |
595 | * Lowest-prio notifier priority, we want to be notified last: | |
596 | */ | |
597 | .priority = -INT_MAX, | |
598 | }; | |
599 | ||
600 | /** | |
601 | * kgdb_arch_init - Perform any architecture specific initalization. | |
602 | * | |
603 | * This function will handle the initalization of any architecture | |
604 | * specific callbacks. | |
605 | */ | |
606 | int kgdb_arch_init(void) | |
607 | { | |
cc096749 JW |
608 | int i, cpu; |
609 | int ret; | |
610 | struct perf_event_attr attr; | |
611 | struct perf_event **pevent; | |
612 | ||
613 | ret = register_die_notifier(&kgdb_notifier); | |
614 | if (ret != 0) | |
615 | return ret; | |
616 | /* | |
617 | * Pre-allocate the hw breakpoint structions in the non-atomic | |
618 | * portion of kgdb because this operation requires mutexs to | |
619 | * complete. | |
620 | */ | |
621 | attr.bp_addr = (unsigned long)kgdb_arch_init; | |
622 | attr.type = PERF_TYPE_BREAKPOINT; | |
623 | attr.bp_len = HW_BREAKPOINT_LEN_1; | |
624 | attr.bp_type = HW_BREAKPOINT_W; | |
625 | attr.disabled = 1; | |
626 | for (i = 0; i < 4; i++) { | |
627 | breakinfo[i].pev = register_wide_hw_breakpoint(&attr, NULL); | |
628 | if (IS_ERR(breakinfo[i].pev)) { | |
629 | printk(KERN_ERR "kgdb: Could not allocate hw breakpoints\n"); | |
630 | breakinfo[i].pev = NULL; | |
631 | kgdb_arch_exit(); | |
632 | return -1; | |
633 | } | |
634 | for_each_online_cpu(cpu) { | |
635 | pevent = per_cpu_ptr(breakinfo[i].pev, cpu); | |
636 | pevent[0]->hw.sample_period = 1; | |
637 | if (pevent[0]->destroy != NULL) { | |
638 | pevent[0]->destroy = NULL; | |
639 | release_bp_slot(*pevent); | |
640 | } | |
641 | } | |
642 | } | |
643 | return ret; | |
82da3ff8 IM |
644 | } |
645 | ||
646 | /** | |
647 | * kgdb_arch_exit - Perform any architecture specific uninitalization. | |
648 | * | |
649 | * This function will handle the uninitalization of any architecture | |
650 | * specific callbacks, for dynamic registration and unregistration. | |
651 | */ | |
652 | void kgdb_arch_exit(void) | |
653 | { | |
cc096749 JW |
654 | int i; |
655 | for (i = 0; i < 4; i++) { | |
656 | if (breakinfo[i].pev) { | |
657 | unregister_wide_hw_breakpoint(breakinfo[i].pev); | |
658 | breakinfo[i].pev = NULL; | |
659 | } | |
660 | } | |
82da3ff8 IM |
661 | unregister_die_notifier(&kgdb_notifier); |
662 | } | |
663 | ||
664 | /** | |
665 | * | |
666 | * kgdb_skipexception - Bail out of KGDB when we've been triggered. | |
667 | * @exception: Exception vector number | |
668 | * @regs: Current &struct pt_regs. | |
669 | * | |
670 | * On some architectures we need to skip a breakpoint exception when | |
671 | * it occurs after a breakpoint has been removed. | |
672 | * | |
673 | * Skip an int3 exception when it occurs after a breakpoint has been | |
674 | * removed. Backtrack eip by 1 since the int3 would have caused it to | |
675 | * increment by 1. | |
676 | */ | |
677 | int kgdb_skipexception(int exception, struct pt_regs *regs) | |
678 | { | |
679 | if (exception == 3 && kgdb_isremovedbreak(regs->ip - 1)) { | |
680 | regs->ip -= 1; | |
681 | return 1; | |
682 | } | |
683 | return 0; | |
684 | } | |
685 | ||
686 | unsigned long kgdb_arch_pc(int exception, struct pt_regs *regs) | |
687 | { | |
688 | if (exception == 3) | |
689 | return instruction_pointer(regs) - 1; | |
690 | return instruction_pointer(regs); | |
691 | } | |
692 | ||
693 | struct kgdb_arch arch_kgdb_ops = { | |
694 | /* Breakpoint instruction: */ | |
695 | .gdb_bpt_instr = { 0xcc }, | |
64e9ee30 JW |
696 | .flags = KGDB_HW_BREAKPOINT, |
697 | .set_hw_breakpoint = kgdb_set_hw_break, | |
698 | .remove_hw_breakpoint = kgdb_remove_hw_break, | |
699 | .remove_all_hw_break = kgdb_remove_all_hw_break, | |
700 | .correct_hw_break = kgdb_correct_hw_break, | |
82da3ff8 | 701 | }; |