]>
Commit | Line | Data |
---|---|---|
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/smp.h> | |
43 | #include <linux/nmi.h> | |
44 | #include <linux/hw_breakpoint.h> | |
45 | #include <linux/uaccess.h> | |
46 | #include <linux/memory.h> | |
47 | ||
48 | #include <asm/text-patching.h> | |
49 | #include <asm/debugreg.h> | |
50 | #include <asm/apicdef.h> | |
51 | #include <asm/apic.h> | |
52 | #include <asm/nmi.h> | |
53 | #include <asm/switch_to.h> | |
54 | ||
55 | struct dbg_reg_def_t dbg_reg_def[DBG_MAX_REG_NUM] = | |
56 | { | |
57 | #ifdef CONFIG_X86_32 | |
58 | { "ax", 4, offsetof(struct pt_regs, ax) }, | |
59 | { "cx", 4, offsetof(struct pt_regs, cx) }, | |
60 | { "dx", 4, offsetof(struct pt_regs, dx) }, | |
61 | { "bx", 4, offsetof(struct pt_regs, bx) }, | |
62 | { "sp", 4, offsetof(struct pt_regs, sp) }, | |
63 | { "bp", 4, offsetof(struct pt_regs, bp) }, | |
64 | { "si", 4, offsetof(struct pt_regs, si) }, | |
65 | { "di", 4, offsetof(struct pt_regs, di) }, | |
66 | { "ip", 4, offsetof(struct pt_regs, ip) }, | |
67 | { "flags", 4, offsetof(struct pt_regs, flags) }, | |
68 | { "cs", 4, offsetof(struct pt_regs, cs) }, | |
69 | { "ss", 4, offsetof(struct pt_regs, ss) }, | |
70 | { "ds", 4, offsetof(struct pt_regs, ds) }, | |
71 | { "es", 4, offsetof(struct pt_regs, es) }, | |
72 | #else | |
73 | { "ax", 8, offsetof(struct pt_regs, ax) }, | |
74 | { "bx", 8, offsetof(struct pt_regs, bx) }, | |
75 | { "cx", 8, offsetof(struct pt_regs, cx) }, | |
76 | { "dx", 8, offsetof(struct pt_regs, dx) }, | |
77 | { "si", 8, offsetof(struct pt_regs, si) }, | |
78 | { "di", 8, offsetof(struct pt_regs, di) }, | |
79 | { "bp", 8, offsetof(struct pt_regs, bp) }, | |
80 | { "sp", 8, offsetof(struct pt_regs, sp) }, | |
81 | { "r8", 8, offsetof(struct pt_regs, r8) }, | |
82 | { "r9", 8, offsetof(struct pt_regs, r9) }, | |
83 | { "r10", 8, offsetof(struct pt_regs, r10) }, | |
84 | { "r11", 8, offsetof(struct pt_regs, r11) }, | |
85 | { "r12", 8, offsetof(struct pt_regs, r12) }, | |
86 | { "r13", 8, offsetof(struct pt_regs, r13) }, | |
87 | { "r14", 8, offsetof(struct pt_regs, r14) }, | |
88 | { "r15", 8, offsetof(struct pt_regs, r15) }, | |
89 | { "ip", 8, offsetof(struct pt_regs, ip) }, | |
90 | { "flags", 4, offsetof(struct pt_regs, flags) }, | |
91 | { "cs", 4, offsetof(struct pt_regs, cs) }, | |
92 | { "ss", 4, offsetof(struct pt_regs, ss) }, | |
93 | { "ds", 4, -1 }, | |
94 | { "es", 4, -1 }, | |
95 | #endif | |
96 | { "fs", 4, -1 }, | |
97 | { "gs", 4, -1 }, | |
98 | }; | |
99 | ||
100 | int dbg_set_reg(int regno, void *mem, struct pt_regs *regs) | |
101 | { | |
102 | if ( | |
103 | #ifdef CONFIG_X86_32 | |
104 | regno == GDB_SS || regno == GDB_FS || regno == GDB_GS || | |
105 | #endif | |
106 | regno == GDB_SP || regno == GDB_ORIG_AX) | |
107 | return 0; | |
108 | ||
109 | if (dbg_reg_def[regno].offset != -1) | |
110 | memcpy((void *)regs + dbg_reg_def[regno].offset, mem, | |
111 | dbg_reg_def[regno].size); | |
112 | return 0; | |
113 | } | |
114 | ||
115 | char *dbg_get_reg(int regno, void *mem, struct pt_regs *regs) | |
116 | { | |
117 | if (regno == GDB_ORIG_AX) { | |
118 | memcpy(mem, ®s->orig_ax, sizeof(regs->orig_ax)); | |
119 | return "orig_ax"; | |
120 | } | |
121 | if (regno >= DBG_MAX_REG_NUM || regno < 0) | |
122 | return NULL; | |
123 | ||
124 | if (dbg_reg_def[regno].offset != -1) | |
125 | memcpy(mem, (void *)regs + dbg_reg_def[regno].offset, | |
126 | dbg_reg_def[regno].size); | |
127 | ||
128 | #ifdef CONFIG_X86_32 | |
129 | switch (regno) { | |
130 | case GDB_SS: | |
131 | if (!user_mode(regs)) | |
132 | *(unsigned long *)mem = __KERNEL_DS; | |
133 | break; | |
134 | case GDB_SP: | |
135 | if (!user_mode(regs)) | |
136 | *(unsigned long *)mem = kernel_stack_pointer(regs); | |
137 | break; | |
138 | case GDB_GS: | |
139 | case GDB_FS: | |
140 | *(unsigned long *)mem = 0xFFFF; | |
141 | break; | |
142 | } | |
143 | #endif | |
144 | return dbg_reg_def[regno].name; | |
145 | } | |
146 | ||
147 | /** | |
148 | * sleeping_thread_to_gdb_regs - Convert ptrace regs to GDB regs | |
149 | * @gdb_regs: A pointer to hold the registers in the order GDB wants. | |
150 | * @p: The &struct task_struct of the desired process. | |
151 | * | |
152 | * Convert the register values of the sleeping process in @p to | |
153 | * the format that GDB expects. | |
154 | * This function is called when kgdb does not have access to the | |
155 | * &struct pt_regs and therefore it should fill the gdb registers | |
156 | * @gdb_regs with what has been saved in &struct thread_struct | |
157 | * thread field during switch_to. | |
158 | */ | |
159 | void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p) | |
160 | { | |
161 | #ifndef CONFIG_X86_32 | |
162 | u32 *gdb_regs32 = (u32 *)gdb_regs; | |
163 | #endif | |
164 | gdb_regs[GDB_AX] = 0; | |
165 | gdb_regs[GDB_BX] = 0; | |
166 | gdb_regs[GDB_CX] = 0; | |
167 | gdb_regs[GDB_DX] = 0; | |
168 | gdb_regs[GDB_SI] = 0; | |
169 | gdb_regs[GDB_DI] = 0; | |
170 | gdb_regs[GDB_BP] = ((struct inactive_task_frame *)p->thread.sp)->bp; | |
171 | #ifdef CONFIG_X86_32 | |
172 | gdb_regs[GDB_DS] = __KERNEL_DS; | |
173 | gdb_regs[GDB_ES] = __KERNEL_DS; | |
174 | gdb_regs[GDB_PS] = 0; | |
175 | gdb_regs[GDB_CS] = __KERNEL_CS; | |
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] = 0; | |
181 | gdb_regs32[GDB_CS] = __KERNEL_CS; | |
182 | gdb_regs32[GDB_SS] = __KERNEL_DS; | |
183 | gdb_regs[GDB_R8] = 0; | |
184 | gdb_regs[GDB_R9] = 0; | |
185 | gdb_regs[GDB_R10] = 0; | |
186 | gdb_regs[GDB_R11] = 0; | |
187 | gdb_regs[GDB_R12] = 0; | |
188 | gdb_regs[GDB_R13] = 0; | |
189 | gdb_regs[GDB_R14] = 0; | |
190 | gdb_regs[GDB_R15] = 0; | |
191 | #endif | |
192 | gdb_regs[GDB_PC] = 0; | |
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(NMI_VECTOR); | |
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 DECLARE_BITMAP(was_in_debug_nmi, NR_CPUS); | |
516 | ||
517 | static int kgdb_nmi_handler(unsigned int cmd, struct pt_regs *regs) | |
518 | { | |
519 | int cpu; | |
520 | ||
521 | switch (cmd) { | |
522 | case NMI_LOCAL: | |
523 | if (atomic_read(&kgdb_active) != -1) { | |
524 | /* KGDB CPU roundup */ | |
525 | cpu = raw_smp_processor_id(); | |
526 | kgdb_nmicallback(cpu, regs); | |
527 | set_bit(cpu, was_in_debug_nmi); | |
528 | touch_nmi_watchdog(); | |
529 | ||
530 | return NMI_HANDLED; | |
531 | } | |
532 | break; | |
533 | ||
534 | case NMI_UNKNOWN: | |
535 | cpu = raw_smp_processor_id(); | |
536 | ||
537 | if (__test_and_clear_bit(cpu, was_in_debug_nmi)) | |
538 | return NMI_HANDLED; | |
539 | ||
540 | break; | |
541 | default: | |
542 | /* do nothing */ | |
543 | break; | |
544 | } | |
545 | return NMI_DONE; | |
546 | } | |
547 | ||
548 | static int __kgdb_notify(struct die_args *args, unsigned long cmd) | |
549 | { | |
550 | struct pt_regs *regs = args->regs; | |
551 | ||
552 | switch (cmd) { | |
553 | case DIE_DEBUG: | |
554 | if (atomic_read(&kgdb_cpu_doing_single_step) != -1) { | |
555 | if (user_mode(regs)) | |
556 | return single_step_cont(regs, args); | |
557 | break; | |
558 | } else if (test_thread_flag(TIF_SINGLESTEP)) | |
559 | /* This means a user thread is single stepping | |
560 | * a system call which should be ignored | |
561 | */ | |
562 | return NOTIFY_DONE; | |
563 | /* fall through */ | |
564 | default: | |
565 | if (user_mode(regs)) | |
566 | return NOTIFY_DONE; | |
567 | } | |
568 | ||
569 | if (kgdb_handle_exception(args->trapnr, args->signr, cmd, regs)) | |
570 | return NOTIFY_DONE; | |
571 | ||
572 | /* Must touch watchdog before return to normal operation */ | |
573 | touch_nmi_watchdog(); | |
574 | return NOTIFY_STOP; | |
575 | } | |
576 | ||
577 | int kgdb_ll_trap(int cmd, const char *str, | |
578 | struct pt_regs *regs, long err, int trap, int sig) | |
579 | { | |
580 | struct die_args args = { | |
581 | .regs = regs, | |
582 | .str = str, | |
583 | .err = err, | |
584 | .trapnr = trap, | |
585 | .signr = sig, | |
586 | ||
587 | }; | |
588 | ||
589 | if (!kgdb_io_module_registered) | |
590 | return NOTIFY_DONE; | |
591 | ||
592 | return __kgdb_notify(&args, cmd); | |
593 | } | |
594 | ||
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 | /** | |
613 | * kgdb_arch_init - Perform any architecture specific initialization. | |
614 | * | |
615 | * This function will handle the initialization of any architecture | |
616 | * specific callbacks. | |
617 | */ | |
618 | int kgdb_arch_init(void) | |
619 | { | |
620 | int retval; | |
621 | ||
622 | retval = register_die_notifier(&kgdb_notifier); | |
623 | if (retval) | |
624 | goto out; | |
625 | ||
626 | retval = register_nmi_handler(NMI_LOCAL, kgdb_nmi_handler, | |
627 | 0, "kgdb"); | |
628 | if (retval) | |
629 | goto out1; | |
630 | ||
631 | retval = register_nmi_handler(NMI_UNKNOWN, kgdb_nmi_handler, | |
632 | 0, "kgdb"); | |
633 | ||
634 | if (retval) | |
635 | goto out2; | |
636 | ||
637 | return retval; | |
638 | ||
639 | out2: | |
640 | unregister_nmi_handler(NMI_LOCAL, "kgdb"); | |
641 | out1: | |
642 | unregister_die_notifier(&kgdb_notifier); | |
643 | out: | |
644 | return retval; | |
645 | } | |
646 | ||
647 | static void kgdb_hw_overflow_handler(struct perf_event *event, | |
648 | struct perf_sample_data *data, struct pt_regs *regs) | |
649 | { | |
650 | struct task_struct *tsk = current; | |
651 | int i; | |
652 | ||
653 | for (i = 0; i < 4; i++) | |
654 | if (breakinfo[i].enabled) | |
655 | tsk->thread.debugreg6 |= (DR_TRAP0 << i); | |
656 | } | |
657 | ||
658 | void kgdb_arch_late(void) | |
659 | { | |
660 | int i, cpu; | |
661 | struct perf_event_attr attr; | |
662 | struct perf_event **pevent; | |
663 | ||
664 | /* | |
665 | * Pre-allocate the hw breakpoint structions in the non-atomic | |
666 | * portion of kgdb because this operation requires mutexs to | |
667 | * complete. | |
668 | */ | |
669 | hw_breakpoint_init(&attr); | |
670 | attr.bp_addr = (unsigned long)kgdb_arch_init; | |
671 | attr.bp_len = HW_BREAKPOINT_LEN_1; | |
672 | attr.bp_type = HW_BREAKPOINT_W; | |
673 | attr.disabled = 1; | |
674 | for (i = 0; i < HBP_NUM; i++) { | |
675 | if (breakinfo[i].pev) | |
676 | continue; | |
677 | breakinfo[i].pev = register_wide_hw_breakpoint(&attr, NULL, NULL); | |
678 | if (IS_ERR((void * __force)breakinfo[i].pev)) { | |
679 | printk(KERN_ERR "kgdb: Could not allocate hw" | |
680 | "breakpoints\nDisabling the kernel debugger\n"); | |
681 | breakinfo[i].pev = NULL; | |
682 | kgdb_arch_exit(); | |
683 | return; | |
684 | } | |
685 | for_each_online_cpu(cpu) { | |
686 | pevent = per_cpu_ptr(breakinfo[i].pev, cpu); | |
687 | pevent[0]->hw.sample_period = 1; | |
688 | pevent[0]->overflow_handler = kgdb_hw_overflow_handler; | |
689 | if (pevent[0]->destroy != NULL) { | |
690 | pevent[0]->destroy = NULL; | |
691 | release_bp_slot(*pevent); | |
692 | } | |
693 | } | |
694 | } | |
695 | } | |
696 | ||
697 | /** | |
698 | * kgdb_arch_exit - Perform any architecture specific uninitalization. | |
699 | * | |
700 | * This function will handle the uninitalization of any architecture | |
701 | * specific callbacks, for dynamic registration and unregistration. | |
702 | */ | |
703 | void kgdb_arch_exit(void) | |
704 | { | |
705 | int i; | |
706 | for (i = 0; i < 4; i++) { | |
707 | if (breakinfo[i].pev) { | |
708 | unregister_wide_hw_breakpoint(breakinfo[i].pev); | |
709 | breakinfo[i].pev = NULL; | |
710 | } | |
711 | } | |
712 | unregister_nmi_handler(NMI_UNKNOWN, "kgdb"); | |
713 | unregister_nmi_handler(NMI_LOCAL, "kgdb"); | |
714 | unregister_die_notifier(&kgdb_notifier); | |
715 | } | |
716 | ||
717 | /** | |
718 | * | |
719 | * kgdb_skipexception - Bail out of KGDB when we've been triggered. | |
720 | * @exception: Exception vector number | |
721 | * @regs: Current &struct pt_regs. | |
722 | * | |
723 | * On some architectures we need to skip a breakpoint exception when | |
724 | * it occurs after a breakpoint has been removed. | |
725 | * | |
726 | * Skip an int3 exception when it occurs after a breakpoint has been | |
727 | * removed. Backtrack eip by 1 since the int3 would have caused it to | |
728 | * increment by 1. | |
729 | */ | |
730 | int kgdb_skipexception(int exception, struct pt_regs *regs) | |
731 | { | |
732 | if (exception == 3 && kgdb_isremovedbreak(regs->ip - 1)) { | |
733 | regs->ip -= 1; | |
734 | return 1; | |
735 | } | |
736 | return 0; | |
737 | } | |
738 | ||
739 | unsigned long kgdb_arch_pc(int exception, struct pt_regs *regs) | |
740 | { | |
741 | if (exception == 3) | |
742 | return instruction_pointer(regs) - 1; | |
743 | return instruction_pointer(regs); | |
744 | } | |
745 | ||
746 | void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long ip) | |
747 | { | |
748 | regs->ip = ip; | |
749 | } | |
750 | ||
751 | int kgdb_arch_set_breakpoint(struct kgdb_bkpt *bpt) | |
752 | { | |
753 | int err; | |
754 | char opc[BREAK_INSTR_SIZE]; | |
755 | ||
756 | bpt->type = BP_BREAKPOINT; | |
757 | err = probe_kernel_read(bpt->saved_instr, (char *)bpt->bpt_addr, | |
758 | BREAK_INSTR_SIZE); | |
759 | if (err) | |
760 | return err; | |
761 | err = probe_kernel_write((char *)bpt->bpt_addr, | |
762 | arch_kgdb_ops.gdb_bpt_instr, BREAK_INSTR_SIZE); | |
763 | if (!err) | |
764 | return err; | |
765 | /* | |
766 | * It is safe to call text_poke() because normal kernel execution | |
767 | * is stopped on all cores, so long as the text_mutex is not locked. | |
768 | */ | |
769 | if (mutex_is_locked(&text_mutex)) | |
770 | return -EBUSY; | |
771 | text_poke((void *)bpt->bpt_addr, arch_kgdb_ops.gdb_bpt_instr, | |
772 | BREAK_INSTR_SIZE); | |
773 | err = probe_kernel_read(opc, (char *)bpt->bpt_addr, BREAK_INSTR_SIZE); | |
774 | if (err) | |
775 | return err; | |
776 | if (memcmp(opc, arch_kgdb_ops.gdb_bpt_instr, BREAK_INSTR_SIZE)) | |
777 | return -EINVAL; | |
778 | bpt->type = BP_POKE_BREAKPOINT; | |
779 | ||
780 | return err; | |
781 | } | |
782 | ||
783 | int kgdb_arch_remove_breakpoint(struct kgdb_bkpt *bpt) | |
784 | { | |
785 | int err; | |
786 | char opc[BREAK_INSTR_SIZE]; | |
787 | ||
788 | if (bpt->type != BP_POKE_BREAKPOINT) | |
789 | goto knl_write; | |
790 | /* | |
791 | * It is safe to call text_poke() because normal kernel execution | |
792 | * is stopped on all cores, so long as the text_mutex is not locked. | |
793 | */ | |
794 | if (mutex_is_locked(&text_mutex)) | |
795 | goto knl_write; | |
796 | text_poke((void *)bpt->bpt_addr, bpt->saved_instr, BREAK_INSTR_SIZE); | |
797 | err = probe_kernel_read(opc, (char *)bpt->bpt_addr, BREAK_INSTR_SIZE); | |
798 | if (err || memcmp(opc, bpt->saved_instr, BREAK_INSTR_SIZE)) | |
799 | goto knl_write; | |
800 | return err; | |
801 | ||
802 | knl_write: | |
803 | return probe_kernel_write((char *)bpt->bpt_addr, | |
804 | (char *)bpt->saved_instr, BREAK_INSTR_SIZE); | |
805 | } | |
806 | ||
807 | struct kgdb_arch arch_kgdb_ops = { | |
808 | /* Breakpoint instruction: */ | |
809 | .gdb_bpt_instr = { 0xcc }, | |
810 | .flags = KGDB_HW_BREAKPOINT, | |
811 | .set_hw_breakpoint = kgdb_set_hw_break, | |
812 | .remove_hw_breakpoint = kgdb_remove_hw_break, | |
813 | .disable_hw_break = kgdb_disable_hw_debug, | |
814 | .remove_all_hw_break = kgdb_remove_all_hw_break, | |
815 | .correct_hw_break = kgdb_correct_hw_break, | |
816 | }; |