Commit | Line | Data |
---|---|---|
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 | |
82da3ff8 IM |
52 | /** |
53 | * pt_regs_to_gdb_regs - Convert ptrace regs to GDB regs | |
54 | * @gdb_regs: A pointer to hold the registers in the order GDB wants. | |
55 | * @regs: The &struct pt_regs of the current process. | |
56 | * | |
57 | * Convert the pt_regs in @regs into the format for registers that | |
58 | * GDB expects, stored in @gdb_regs. | |
59 | */ | |
60 | void pt_regs_to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *regs) | |
61 | { | |
703a1edc JW |
62 | #ifndef CONFIG_X86_32 |
63 | u32 *gdb_regs32 = (u32 *)gdb_regs; | |
64 | #endif | |
82da3ff8 IM |
65 | gdb_regs[GDB_AX] = regs->ax; |
66 | gdb_regs[GDB_BX] = regs->bx; | |
67 | gdb_regs[GDB_CX] = regs->cx; | |
68 | gdb_regs[GDB_DX] = regs->dx; | |
69 | gdb_regs[GDB_SI] = regs->si; | |
70 | gdb_regs[GDB_DI] = regs->di; | |
71 | gdb_regs[GDB_BP] = regs->bp; | |
82da3ff8 IM |
72 | gdb_regs[GDB_PC] = regs->ip; |
73 | #ifdef CONFIG_X86_32 | |
703a1edc | 74 | gdb_regs[GDB_PS] = regs->flags; |
82da3ff8 IM |
75 | gdb_regs[GDB_DS] = regs->ds; |
76 | gdb_regs[GDB_ES] = regs->es; | |
77 | gdb_regs[GDB_CS] = regs->cs; | |
82da3ff8 IM |
78 | gdb_regs[GDB_FS] = 0xFFFF; |
79 | gdb_regs[GDB_GS] = 0xFFFF; | |
cf6f196d JW |
80 | if (user_mode_vm(regs)) { |
81 | gdb_regs[GDB_SS] = regs->ss; | |
82 | gdb_regs[GDB_SP] = regs->sp; | |
83 | } else { | |
84 | gdb_regs[GDB_SS] = __KERNEL_DS; | |
85 | gdb_regs[GDB_SP] = kernel_stack_pointer(regs); | |
86 | } | |
82da3ff8 IM |
87 | #else |
88 | gdb_regs[GDB_R8] = regs->r8; | |
89 | gdb_regs[GDB_R9] = regs->r9; | |
90 | gdb_regs[GDB_R10] = regs->r10; | |
91 | gdb_regs[GDB_R11] = regs->r11; | |
92 | gdb_regs[GDB_R12] = regs->r12; | |
93 | gdb_regs[GDB_R13] = regs->r13; | |
94 | gdb_regs[GDB_R14] = regs->r14; | |
95 | gdb_regs[GDB_R15] = regs->r15; | |
703a1edc JW |
96 | gdb_regs32[GDB_PS] = regs->flags; |
97 | gdb_regs32[GDB_CS] = regs->cs; | |
98 | gdb_regs32[GDB_SS] = regs->ss; | |
5ca6c0ca | 99 | gdb_regs[GDB_SP] = kernel_stack_pointer(regs); |
cf6f196d | 100 | #endif |
82da3ff8 IM |
101 | } |
102 | ||
103 | /** | |
104 | * sleeping_thread_to_gdb_regs - Convert ptrace regs to GDB regs | |
105 | * @gdb_regs: A pointer to hold the registers in the order GDB wants. | |
106 | * @p: The &struct task_struct of the desired process. | |
107 | * | |
108 | * Convert the register values of the sleeping process in @p to | |
109 | * the format that GDB expects. | |
110 | * This function is called when kgdb does not have access to the | |
111 | * &struct pt_regs and therefore it should fill the gdb registers | |
112 | * @gdb_regs with what has been saved in &struct thread_struct | |
113 | * thread field during switch_to. | |
114 | */ | |
115 | void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p) | |
116 | { | |
703a1edc JW |
117 | #ifndef CONFIG_X86_32 |
118 | u32 *gdb_regs32 = (u32 *)gdb_regs; | |
119 | #endif | |
82da3ff8 IM |
120 | gdb_regs[GDB_AX] = 0; |
121 | gdb_regs[GDB_BX] = 0; | |
122 | gdb_regs[GDB_CX] = 0; | |
123 | gdb_regs[GDB_DX] = 0; | |
124 | gdb_regs[GDB_SI] = 0; | |
125 | gdb_regs[GDB_DI] = 0; | |
126 | gdb_regs[GDB_BP] = *(unsigned long *)p->thread.sp; | |
127 | #ifdef CONFIG_X86_32 | |
128 | gdb_regs[GDB_DS] = __KERNEL_DS; | |
129 | gdb_regs[GDB_ES] = __KERNEL_DS; | |
130 | gdb_regs[GDB_PS] = 0; | |
131 | gdb_regs[GDB_CS] = __KERNEL_CS; | |
132 | gdb_regs[GDB_PC] = p->thread.ip; | |
133 | gdb_regs[GDB_SS] = __KERNEL_DS; | |
134 | gdb_regs[GDB_FS] = 0xFFFF; | |
135 | gdb_regs[GDB_GS] = 0xFFFF; | |
136 | #else | |
703a1edc JW |
137 | gdb_regs32[GDB_PS] = *(unsigned long *)(p->thread.sp + 8); |
138 | gdb_regs32[GDB_CS] = __KERNEL_CS; | |
139 | gdb_regs32[GDB_SS] = __KERNEL_DS; | |
0c23590f | 140 | gdb_regs[GDB_PC] = 0; |
82da3ff8 IM |
141 | gdb_regs[GDB_R8] = 0; |
142 | gdb_regs[GDB_R9] = 0; | |
143 | gdb_regs[GDB_R10] = 0; | |
144 | gdb_regs[GDB_R11] = 0; | |
145 | gdb_regs[GDB_R12] = 0; | |
146 | gdb_regs[GDB_R13] = 0; | |
147 | gdb_regs[GDB_R14] = 0; | |
148 | gdb_regs[GDB_R15] = 0; | |
149 | #endif | |
150 | gdb_regs[GDB_SP] = p->thread.sp; | |
151 | } | |
152 | ||
153 | /** | |
154 | * gdb_regs_to_pt_regs - Convert GDB regs to ptrace regs. | |
155 | * @gdb_regs: A pointer to hold the registers we've received from GDB. | |
156 | * @regs: A pointer to a &struct pt_regs to hold these values in. | |
157 | * | |
158 | * Convert the GDB regs in @gdb_regs into the pt_regs, and store them | |
159 | * in @regs. | |
160 | */ | |
161 | void gdb_regs_to_pt_regs(unsigned long *gdb_regs, struct pt_regs *regs) | |
162 | { | |
703a1edc JW |
163 | #ifndef CONFIG_X86_32 |
164 | u32 *gdb_regs32 = (u32 *)gdb_regs; | |
165 | #endif | |
82da3ff8 IM |
166 | regs->ax = gdb_regs[GDB_AX]; |
167 | regs->bx = gdb_regs[GDB_BX]; | |
168 | regs->cx = gdb_regs[GDB_CX]; | |
169 | regs->dx = gdb_regs[GDB_DX]; | |
170 | regs->si = gdb_regs[GDB_SI]; | |
171 | regs->di = gdb_regs[GDB_DI]; | |
172 | regs->bp = gdb_regs[GDB_BP]; | |
82da3ff8 IM |
173 | regs->ip = gdb_regs[GDB_PC]; |
174 | #ifdef CONFIG_X86_32 | |
703a1edc | 175 | regs->flags = gdb_regs[GDB_PS]; |
82da3ff8 IM |
176 | regs->ds = gdb_regs[GDB_DS]; |
177 | regs->es = gdb_regs[GDB_ES]; | |
178 | regs->cs = gdb_regs[GDB_CS]; | |
179 | #else | |
180 | regs->r8 = gdb_regs[GDB_R8]; | |
181 | regs->r9 = gdb_regs[GDB_R9]; | |
182 | regs->r10 = gdb_regs[GDB_R10]; | |
183 | regs->r11 = gdb_regs[GDB_R11]; | |
184 | regs->r12 = gdb_regs[GDB_R12]; | |
185 | regs->r13 = gdb_regs[GDB_R13]; | |
186 | regs->r14 = gdb_regs[GDB_R14]; | |
187 | regs->r15 = gdb_regs[GDB_R15]; | |
703a1edc JW |
188 | regs->flags = gdb_regs32[GDB_PS]; |
189 | regs->cs = gdb_regs32[GDB_CS]; | |
190 | regs->ss = gdb_regs32[GDB_SS]; | |
82da3ff8 IM |
191 | #endif |
192 | } | |
193 | ||
64e9ee30 JW |
194 | static struct hw_breakpoint { |
195 | unsigned enabled; | |
64e9ee30 | 196 | unsigned long addr; |
cc096749 JW |
197 | int len; |
198 | int type; | |
199 | struct perf_event **pev; | |
64e9ee30 JW |
200 | } breakinfo[4]; |
201 | ||
031acd8c JW |
202 | static unsigned long early_dr7; |
203 | ||
64e9ee30 JW |
204 | static void kgdb_correct_hw_break(void) |
205 | { | |
64e9ee30 JW |
206 | int breakno; |
207 | ||
64e9ee30 | 208 | for (breakno = 0; breakno < 4; breakno++) { |
cc096749 JW |
209 | struct perf_event *bp; |
210 | struct arch_hw_breakpoint *info; | |
211 | int val; | |
212 | int cpu = raw_smp_processor_id(); | |
213 | if (!breakinfo[breakno].enabled) | |
214 | continue; | |
031acd8c JW |
215 | if (dbg_is_early) { |
216 | set_debugreg(breakinfo[breakno].addr, breakno); | |
217 | early_dr7 |= encode_dr7(breakno, | |
218 | breakinfo[breakno].len, | |
219 | breakinfo[breakno].type); | |
220 | set_debugreg(early_dr7, 7); | |
221 | continue; | |
222 | } | |
cc096749 JW |
223 | bp = *per_cpu_ptr(breakinfo[breakno].pev, cpu); |
224 | info = counter_arch_bp(bp); | |
225 | if (bp->attr.disabled != 1) | |
226 | continue; | |
227 | bp->attr.bp_addr = breakinfo[breakno].addr; | |
228 | bp->attr.bp_len = breakinfo[breakno].len; | |
229 | bp->attr.bp_type = breakinfo[breakno].type; | |
230 | info->address = breakinfo[breakno].addr; | |
231 | info->len = breakinfo[breakno].len; | |
232 | info->type = breakinfo[breakno].type; | |
233 | val = arch_install_hw_breakpoint(bp); | |
234 | if (!val) | |
235 | bp->attr.disabled = 0; | |
64e9ee30 | 236 | } |
031acd8c JW |
237 | if (!dbg_is_early) |
238 | hw_breakpoint_restore(); | |
64e9ee30 JW |
239 | } |
240 | ||
5352ae63 JW |
241 | static int hw_break_reserve_slot(int breakno) |
242 | { | |
243 | int cpu; | |
244 | int cnt = 0; | |
245 | struct perf_event **pevent; | |
246 | ||
031acd8c JW |
247 | if (dbg_is_early) |
248 | return 0; | |
249 | ||
5352ae63 JW |
250 | for_each_online_cpu(cpu) { |
251 | cnt++; | |
252 | pevent = per_cpu_ptr(breakinfo[breakno].pev, cpu); | |
253 | if (dbg_reserve_bp_slot(*pevent)) | |
254 | goto fail; | |
255 | } | |
256 | ||
257 | return 0; | |
258 | ||
259 | fail: | |
260 | for_each_online_cpu(cpu) { | |
261 | cnt--; | |
262 | if (!cnt) | |
263 | break; | |
264 | pevent = per_cpu_ptr(breakinfo[breakno].pev, cpu); | |
265 | dbg_release_bp_slot(*pevent); | |
266 | } | |
267 | return -1; | |
268 | } | |
269 | ||
270 | static int hw_break_release_slot(int breakno) | |
271 | { | |
272 | struct perf_event **pevent; | |
273 | int cpu; | |
274 | ||
031acd8c JW |
275 | if (dbg_is_early) |
276 | return 0; | |
277 | ||
5352ae63 JW |
278 | for_each_online_cpu(cpu) { |
279 | pevent = per_cpu_ptr(breakinfo[breakno].pev, cpu); | |
280 | if (dbg_release_bp_slot(*pevent)) | |
281 | /* | |
282 | * The debugger is responisble for handing the retry on | |
283 | * remove failure. | |
284 | */ | |
285 | return -1; | |
286 | } | |
287 | return 0; | |
288 | } | |
289 | ||
64e9ee30 JW |
290 | static int |
291 | kgdb_remove_hw_break(unsigned long addr, int len, enum kgdb_bptype bptype) | |
292 | { | |
293 | int i; | |
294 | ||
295 | for (i = 0; i < 4; i++) | |
296 | if (breakinfo[i].addr == addr && breakinfo[i].enabled) | |
297 | break; | |
298 | if (i == 4) | |
299 | return -1; | |
300 | ||
5352ae63 JW |
301 | if (hw_break_release_slot(i)) { |
302 | printk(KERN_ERR "Cannot remove hw breakpoint at %lx\n", addr); | |
303 | return -1; | |
304 | } | |
64e9ee30 JW |
305 | breakinfo[i].enabled = 0; |
306 | ||
307 | return 0; | |
308 | } | |
309 | ||
310 | static void kgdb_remove_all_hw_break(void) | |
311 | { | |
312 | int i; | |
cc096749 JW |
313 | int cpu = raw_smp_processor_id(); |
314 | struct perf_event *bp; | |
64e9ee30 | 315 | |
cc096749 JW |
316 | for (i = 0; i < 4; i++) { |
317 | if (!breakinfo[i].enabled) | |
318 | continue; | |
319 | bp = *per_cpu_ptr(breakinfo[i].pev, cpu); | |
320 | if (bp->attr.disabled == 1) | |
321 | continue; | |
031acd8c JW |
322 | if (dbg_is_early) |
323 | early_dr7 &= ~encode_dr7(i, breakinfo[i].len, | |
324 | breakinfo[i].type); | |
325 | else | |
326 | arch_uninstall_hw_breakpoint(bp); | |
cc096749 JW |
327 | bp->attr.disabled = 1; |
328 | } | |
64e9ee30 JW |
329 | } |
330 | ||
331 | static int | |
332 | kgdb_set_hw_break(unsigned long addr, int len, enum kgdb_bptype bptype) | |
333 | { | |
64e9ee30 JW |
334 | int i; |
335 | ||
336 | for (i = 0; i < 4; i++) | |
337 | if (!breakinfo[i].enabled) | |
338 | break; | |
339 | if (i == 4) | |
340 | return -1; | |
341 | ||
342 | switch (bptype) { | |
343 | case BP_HARDWARE_BREAKPOINT: | |
cc096749 JW |
344 | len = 1; |
345 | breakinfo[i].type = X86_BREAKPOINT_EXECUTE; | |
64e9ee30 JW |
346 | break; |
347 | case BP_WRITE_WATCHPOINT: | |
cc096749 | 348 | breakinfo[i].type = X86_BREAKPOINT_WRITE; |
64e9ee30 JW |
349 | break; |
350 | case BP_ACCESS_WATCHPOINT: | |
cc096749 | 351 | breakinfo[i].type = X86_BREAKPOINT_RW; |
64e9ee30 JW |
352 | break; |
353 | default: | |
354 | return -1; | |
355 | } | |
cc096749 JW |
356 | switch (len) { |
357 | case 1: | |
358 | breakinfo[i].len = X86_BREAKPOINT_LEN_1; | |
359 | break; | |
360 | case 2: | |
361 | breakinfo[i].len = X86_BREAKPOINT_LEN_2; | |
362 | break; | |
363 | case 4: | |
364 | breakinfo[i].len = X86_BREAKPOINT_LEN_4; | |
365 | break; | |
366 | #ifdef CONFIG_X86_64 | |
367 | case 8: | |
368 | breakinfo[i].len = X86_BREAKPOINT_LEN_8; | |
369 | break; | |
370 | #endif | |
371 | default: | |
64e9ee30 | 372 | return -1; |
cc096749 | 373 | } |
64e9ee30 | 374 | breakinfo[i].addr = addr; |
5352ae63 JW |
375 | if (hw_break_reserve_slot(i)) { |
376 | breakinfo[i].addr = 0; | |
377 | return -1; | |
378 | } | |
cc096749 | 379 | breakinfo[i].enabled = 1; |
64e9ee30 JW |
380 | |
381 | return 0; | |
382 | } | |
383 | ||
384 | /** | |
385 | * kgdb_disable_hw_debug - Disable hardware debugging while we in kgdb. | |
386 | * @regs: Current &struct pt_regs. | |
387 | * | |
388 | * This function will be called if the particular architecture must | |
389 | * disable hardware debugging while it is processing gdb packets or | |
390 | * handling exception. | |
391 | */ | |
392 | void kgdb_disable_hw_debug(struct pt_regs *regs) | |
393 | { | |
cc096749 JW |
394 | int i; |
395 | int cpu = raw_smp_processor_id(); | |
396 | struct perf_event *bp; | |
397 | ||
64e9ee30 JW |
398 | /* Disable hardware debugging while we are in kgdb: */ |
399 | set_debugreg(0UL, 7); | |
cc096749 JW |
400 | for (i = 0; i < 4; i++) { |
401 | if (!breakinfo[i].enabled) | |
402 | continue; | |
031acd8c JW |
403 | if (dbg_is_early) { |
404 | early_dr7 &= ~encode_dr7(i, breakinfo[i].len, | |
405 | breakinfo[i].type); | |
406 | continue; | |
407 | } | |
cc096749 JW |
408 | bp = *per_cpu_ptr(breakinfo[i].pev, cpu); |
409 | if (bp->attr.disabled == 1) | |
410 | continue; | |
411 | arch_uninstall_hw_breakpoint(bp); | |
412 | bp->attr.disabled = 1; | |
413 | } | |
64e9ee30 JW |
414 | } |
415 | ||
82da3ff8 IM |
416 | #ifdef CONFIG_SMP |
417 | /** | |
418 | * kgdb_roundup_cpus - Get other CPUs into a holding pattern | |
419 | * @flags: Current IRQ state | |
420 | * | |
421 | * On SMP systems, we need to get the attention of the other CPUs | |
422 | * and get them be in a known state. This should do what is needed | |
423 | * to get the other CPUs to call kgdb_wait(). Note that on some arches, | |
424 | * the NMI approach is not used for rounding up all the CPUs. For example, | |
425 | * in case of MIPS, smp_call_function() is used to roundup CPUs. In | |
426 | * this case, we have to make sure that interrupts are enabled before | |
427 | * calling smp_call_function(). The argument to this function is | |
428 | * the flags that will be used when restoring the interrupts. There is | |
429 | * local_irq_save() call before kgdb_roundup_cpus(). | |
430 | * | |
431 | * On non-SMP systems, this is not called. | |
432 | */ | |
433 | void kgdb_roundup_cpus(unsigned long flags) | |
434 | { | |
dac5f412 | 435 | apic->send_IPI_allbutself(APIC_DM_NMI); |
82da3ff8 IM |
436 | } |
437 | #endif | |
438 | ||
439 | /** | |
440 | * kgdb_arch_handle_exception - Handle architecture specific GDB packets. | |
441 | * @vector: The error vector of the exception that happened. | |
442 | * @signo: The signal number of the exception that happened. | |
443 | * @err_code: The error code of the exception that happened. | |
444 | * @remcom_in_buffer: The buffer of the packet we have read. | |
445 | * @remcom_out_buffer: The buffer of %BUFMAX bytes to write a packet into. | |
446 | * @regs: The &struct pt_regs of the current process. | |
447 | * | |
448 | * This function MUST handle the 'c' and 's' command packets, | |
449 | * as well packets to set / remove a hardware breakpoint, if used. | |
450 | * If there are additional packets which the hardware needs to handle, | |
451 | * they are handled here. The code should return -1 if it wants to | |
452 | * process more packets, and a %0 or %1 if it wants to exit from the | |
453 | * kgdb callback. | |
454 | */ | |
455 | int kgdb_arch_handle_exception(int e_vector, int signo, int err_code, | |
456 | char *remcomInBuffer, char *remcomOutBuffer, | |
457 | struct pt_regs *linux_regs) | |
458 | { | |
459 | unsigned long addr; | |
460 | char *ptr; | |
461 | int newPC; | |
462 | ||
463 | switch (remcomInBuffer[0]) { | |
464 | case 'c': | |
465 | case 's': | |
466 | /* try to read optional parameter, pc unchanged if no parm */ | |
467 | ptr = &remcomInBuffer[1]; | |
468 | if (kgdb_hex2long(&ptr, &addr)) | |
469 | linux_regs->ip = addr; | |
737a460f JW |
470 | case 'D': |
471 | case 'k': | |
82da3ff8 IM |
472 | newPC = linux_regs->ip; |
473 | ||
474 | /* clear the trace bit */ | |
fda31d7d | 475 | linux_regs->flags &= ~X86_EFLAGS_TF; |
82da3ff8 IM |
476 | atomic_set(&kgdb_cpu_doing_single_step, -1); |
477 | ||
478 | /* set the trace bit if we're stepping */ | |
479 | if (remcomInBuffer[0] == 's') { | |
fda31d7d | 480 | linux_regs->flags |= X86_EFLAGS_TF; |
d7161a65 JW |
481 | atomic_set(&kgdb_cpu_doing_single_step, |
482 | raw_smp_processor_id()); | |
82da3ff8 IM |
483 | } |
484 | ||
64e9ee30 JW |
485 | kgdb_correct_hw_break(); |
486 | ||
82da3ff8 IM |
487 | return 0; |
488 | } | |
489 | ||
490 | /* this means that we do not want to exit from the handler: */ | |
491 | return -1; | |
492 | } | |
493 | ||
494 | static inline int | |
495 | single_step_cont(struct pt_regs *regs, struct die_args *args) | |
496 | { | |
497 | /* | |
498 | * Single step exception from kernel space to user space so | |
499 | * eat the exception and continue the process: | |
500 | */ | |
501 | printk(KERN_ERR "KGDB: trap/step from kernel to user space, " | |
502 | "resuming...\n"); | |
503 | kgdb_arch_handle_exception(args->trapnr, args->signr, | |
504 | args->err, "c", "", regs); | |
62edab90 P |
505 | /* |
506 | * Reset the BS bit in dr6 (pointed by args->err) to | |
507 | * denote completion of processing | |
508 | */ | |
509 | (*(unsigned long *)ERR_PTR(args->err)) &= ~DR_STEP; | |
82da3ff8 IM |
510 | |
511 | return NOTIFY_STOP; | |
512 | } | |
513 | ||
d3597524 JW |
514 | static int was_in_debug_nmi[NR_CPUS]; |
515 | ||
82da3ff8 IM |
516 | static int __kgdb_notify(struct die_args *args, unsigned long cmd) |
517 | { | |
518 | struct pt_regs *regs = args->regs; | |
519 | ||
520 | switch (cmd) { | |
521 | case DIE_NMI: | |
522 | if (atomic_read(&kgdb_active) != -1) { | |
523 | /* KGDB CPU roundup */ | |
524 | kgdb_nmicallback(raw_smp_processor_id(), regs); | |
d3597524 JW |
525 | was_in_debug_nmi[raw_smp_processor_id()] = 1; |
526 | touch_nmi_watchdog(); | |
82da3ff8 IM |
527 | return NOTIFY_STOP; |
528 | } | |
529 | return NOTIFY_DONE; | |
530 | ||
531 | case DIE_NMI_IPI: | |
e85ceae9 | 532 | /* Just ignore, we will handle the roundup on DIE_NMI. */ |
d3597524 JW |
533 | return NOTIFY_DONE; |
534 | ||
535 | case DIE_NMIUNKNOWN: | |
536 | if (was_in_debug_nmi[raw_smp_processor_id()]) { | |
537 | was_in_debug_nmi[raw_smp_processor_id()] = 0; | |
82da3ff8 IM |
538 | return NOTIFY_STOP; |
539 | } | |
540 | return NOTIFY_DONE; | |
541 | ||
542 | case DIE_NMIWATCHDOG: | |
543 | if (atomic_read(&kgdb_active) != -1) { | |
544 | /* KGDB CPU roundup: */ | |
545 | kgdb_nmicallback(raw_smp_processor_id(), regs); | |
546 | return NOTIFY_STOP; | |
547 | } | |
548 | /* Enter debugger: */ | |
549 | break; | |
550 | ||
551 | case DIE_DEBUG: | |
cc096749 | 552 | if (atomic_read(&kgdb_cpu_doing_single_step) != -1) { |
d7161a65 JW |
553 | if (user_mode(regs)) |
554 | return single_step_cont(regs, args); | |
555 | break; | |
556 | } else if (test_thread_flag(TIF_SINGLESTEP)) | |
557 | /* This means a user thread is single stepping | |
558 | * a system call which should be ignored | |
559 | */ | |
560 | return NOTIFY_DONE; | |
82da3ff8 IM |
561 | /* fall through */ |
562 | default: | |
563 | if (user_mode(regs)) | |
564 | return NOTIFY_DONE; | |
565 | } | |
566 | ||
f503b5ae | 567 | if (kgdb_handle_exception(args->trapnr, args->signr, cmd, regs)) |
82da3ff8 IM |
568 | return NOTIFY_DONE; |
569 | ||
737a460f JW |
570 | /* Must touch watchdog before return to normal operation */ |
571 | touch_nmi_watchdog(); | |
82da3ff8 IM |
572 | return NOTIFY_STOP; |
573 | } | |
574 | ||
f503b5ae JW |
575 | #ifdef CONFIG_KGDB_LOW_LEVEL_TRAP |
576 | int kgdb_ll_trap(int cmd, const char *str, | |
577 | struct pt_regs *regs, long err, int trap, int sig) | |
578 | { | |
579 | struct die_args args = { | |
580 | .regs = regs, | |
581 | .str = str, | |
582 | .err = err, | |
583 | .trapnr = trap, | |
584 | .signr = sig, | |
585 | ||
586 | }; | |
587 | ||
588 | if (!kgdb_io_module_registered) | |
589 | return NOTIFY_DONE; | |
590 | ||
591 | return __kgdb_notify(&args, cmd); | |
592 | } | |
593 | #endif /* CONFIG_KGDB_LOW_LEVEL_TRAP */ | |
594 | ||
82da3ff8 IM |
595 | static int |
596 | kgdb_notify(struct notifier_block *self, unsigned long cmd, void *ptr) | |
597 | { | |
598 | unsigned long flags; | |
599 | int ret; | |
600 | ||
601 | local_irq_save(flags); | |
602 | ret = __kgdb_notify(ptr, cmd); | |
603 | local_irq_restore(flags); | |
604 | ||
605 | return ret; | |
606 | } | |
607 | ||
608 | static struct notifier_block kgdb_notifier = { | |
609 | .notifier_call = kgdb_notify, | |
610 | ||
611 | /* | |
612 | * Lowest-prio notifier priority, we want to be notified last: | |
613 | */ | |
614 | .priority = -INT_MAX, | |
615 | }; | |
616 | ||
617 | /** | |
618 | * kgdb_arch_init - Perform any architecture specific initalization. | |
619 | * | |
620 | * This function will handle the initalization of any architecture | |
621 | * specific callbacks. | |
622 | */ | |
623 | int kgdb_arch_init(void) | |
0b4b3827 JW |
624 | { |
625 | return register_die_notifier(&kgdb_notifier); | |
626 | } | |
627 | ||
628 | void kgdb_arch_late(void) | |
82da3ff8 | 629 | { |
cc096749 | 630 | int i, cpu; |
cc096749 JW |
631 | struct perf_event_attr attr; |
632 | struct perf_event **pevent; | |
633 | ||
cc096749 JW |
634 | /* |
635 | * Pre-allocate the hw breakpoint structions in the non-atomic | |
636 | * portion of kgdb because this operation requires mutexs to | |
637 | * complete. | |
638 | */ | |
ab310b5e | 639 | hw_breakpoint_init(&attr); |
cc096749 | 640 | attr.bp_addr = (unsigned long)kgdb_arch_init; |
cc096749 JW |
641 | attr.bp_len = HW_BREAKPOINT_LEN_1; |
642 | attr.bp_type = HW_BREAKPOINT_W; | |
643 | attr.disabled = 1; | |
644 | for (i = 0; i < 4; i++) { | |
0b4b3827 JW |
645 | if (breakinfo[i].pev) |
646 | continue; | |
cc096749 JW |
647 | breakinfo[i].pev = register_wide_hw_breakpoint(&attr, NULL); |
648 | if (IS_ERR(breakinfo[i].pev)) { | |
0b4b3827 JW |
649 | printk(KERN_ERR "kgdb: Could not allocate hw" |
650 | "breakpoints\nDisabling the kernel debugger\n"); | |
cc096749 JW |
651 | breakinfo[i].pev = NULL; |
652 | kgdb_arch_exit(); | |
0b4b3827 | 653 | return; |
cc096749 JW |
654 | } |
655 | for_each_online_cpu(cpu) { | |
656 | pevent = per_cpu_ptr(breakinfo[i].pev, cpu); | |
657 | pevent[0]->hw.sample_period = 1; | |
658 | if (pevent[0]->destroy != NULL) { | |
659 | pevent[0]->destroy = NULL; | |
660 | release_bp_slot(*pevent); | |
661 | } | |
662 | } | |
663 | } | |
82da3ff8 IM |
664 | } |
665 | ||
666 | /** | |
667 | * kgdb_arch_exit - Perform any architecture specific uninitalization. | |
668 | * | |
669 | * This function will handle the uninitalization of any architecture | |
670 | * specific callbacks, for dynamic registration and unregistration. | |
671 | */ | |
672 | void kgdb_arch_exit(void) | |
673 | { | |
cc096749 JW |
674 | int i; |
675 | for (i = 0; i < 4; i++) { | |
676 | if (breakinfo[i].pev) { | |
677 | unregister_wide_hw_breakpoint(breakinfo[i].pev); | |
678 | breakinfo[i].pev = NULL; | |
679 | } | |
680 | } | |
82da3ff8 IM |
681 | unregister_die_notifier(&kgdb_notifier); |
682 | } | |
683 | ||
684 | /** | |
685 | * | |
686 | * kgdb_skipexception - Bail out of KGDB when we've been triggered. | |
687 | * @exception: Exception vector number | |
688 | * @regs: Current &struct pt_regs. | |
689 | * | |
690 | * On some architectures we need to skip a breakpoint exception when | |
691 | * it occurs after a breakpoint has been removed. | |
692 | * | |
693 | * Skip an int3 exception when it occurs after a breakpoint has been | |
694 | * removed. Backtrack eip by 1 since the int3 would have caused it to | |
695 | * increment by 1. | |
696 | */ | |
697 | int kgdb_skipexception(int exception, struct pt_regs *regs) | |
698 | { | |
699 | if (exception == 3 && kgdb_isremovedbreak(regs->ip - 1)) { | |
700 | regs->ip -= 1; | |
701 | return 1; | |
702 | } | |
703 | return 0; | |
704 | } | |
705 | ||
706 | unsigned long kgdb_arch_pc(int exception, struct pt_regs *regs) | |
707 | { | |
708 | if (exception == 3) | |
709 | return instruction_pointer(regs) - 1; | |
710 | return instruction_pointer(regs); | |
711 | } | |
712 | ||
dcc78711 JW |
713 | void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long ip) |
714 | { | |
715 | regs->ip = ip; | |
716 | } | |
717 | ||
82da3ff8 IM |
718 | struct kgdb_arch arch_kgdb_ops = { |
719 | /* Breakpoint instruction: */ | |
720 | .gdb_bpt_instr = { 0xcc }, | |
64e9ee30 JW |
721 | .flags = KGDB_HW_BREAKPOINT, |
722 | .set_hw_breakpoint = kgdb_set_hw_break, | |
723 | .remove_hw_breakpoint = kgdb_remove_hw_break, | |
724 | .remove_all_hw_break = kgdb_remove_all_hw_break, | |
725 | .correct_hw_break = kgdb_correct_hw_break, | |
82da3ff8 | 726 | }; |