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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> | |
7b6aa335 | 50 | #include <asm/apic.h> |
166d7514 | 51 | #include <asm/nmi.h> |
82da3ff8 | 52 | |
12bfa3de | 53 | struct dbg_reg_def_t dbg_reg_def[DBG_MAX_REG_NUM] = |
82da3ff8 | 54 | { |
12bfa3de JW |
55 | #ifdef CONFIG_X86_32 |
56 | { "ax", 4, offsetof(struct pt_regs, ax) }, | |
57 | { "cx", 4, offsetof(struct pt_regs, cx) }, | |
58 | { "dx", 4, offsetof(struct pt_regs, dx) }, | |
59 | { "bx", 4, offsetof(struct pt_regs, bx) }, | |
60 | { "sp", 4, offsetof(struct pt_regs, sp) }, | |
61 | { "bp", 4, offsetof(struct pt_regs, bp) }, | |
62 | { "si", 4, offsetof(struct pt_regs, si) }, | |
63 | { "di", 4, offsetof(struct pt_regs, di) }, | |
64 | { "ip", 4, offsetof(struct pt_regs, ip) }, | |
65 | { "flags", 4, offsetof(struct pt_regs, flags) }, | |
66 | { "cs", 4, offsetof(struct pt_regs, cs) }, | |
67 | { "ss", 4, offsetof(struct pt_regs, ss) }, | |
68 | { "ds", 4, offsetof(struct pt_regs, ds) }, | |
69 | { "es", 4, offsetof(struct pt_regs, es) }, | |
70 | { "fs", 4, -1 }, | |
71 | { "gs", 4, -1 }, | |
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, dx) }, | |
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) }, | |
703a1edc | 93 | #endif |
12bfa3de JW |
94 | }; |
95 | ||
96 | int dbg_set_reg(int regno, void *mem, struct pt_regs *regs) | |
97 | { | |
98 | if ( | |
82da3ff8 | 99 | #ifdef CONFIG_X86_32 |
12bfa3de JW |
100 | regno == GDB_SS || regno == GDB_FS || regno == GDB_GS || |
101 | #endif | |
102 | regno == GDB_SP || regno == GDB_ORIG_AX) | |
103 | return 0; | |
104 | ||
105 | if (dbg_reg_def[regno].offset != -1) | |
106 | memcpy((void *)regs + dbg_reg_def[regno].offset, mem, | |
107 | dbg_reg_def[regno].size); | |
108 | return 0; | |
109 | } | |
110 | ||
111 | char *dbg_get_reg(int regno, void *mem, struct pt_regs *regs) | |
112 | { | |
113 | if (regno == GDB_ORIG_AX) { | |
114 | memcpy(mem, ®s->orig_ax, sizeof(regs->orig_ax)); | |
115 | return "orig_ax"; | |
cf6f196d | 116 | } |
12bfa3de JW |
117 | if (regno >= DBG_MAX_REG_NUM || regno < 0) |
118 | return NULL; | |
119 | ||
120 | if (dbg_reg_def[regno].offset != -1) | |
121 | memcpy(mem, (void *)regs + dbg_reg_def[regno].offset, | |
122 | dbg_reg_def[regno].size); | |
123 | ||
12bfa3de | 124 | #ifdef CONFIG_X86_32 |
21431c29 | 125 | switch (regno) { |
12bfa3de JW |
126 | case GDB_SS: |
127 | if (!user_mode_vm(regs)) | |
128 | *(unsigned long *)mem = __KERNEL_DS; | |
129 | break; | |
130 | case GDB_SP: | |
131 | if (!user_mode_vm(regs)) | |
132 | *(unsigned long *)mem = kernel_stack_pointer(regs); | |
133 | break; | |
134 | case GDB_GS: | |
135 | case GDB_FS: | |
136 | *(unsigned long *)mem = 0xFFFF; | |
137 | break; | |
12bfa3de | 138 | } |
21431c29 | 139 | #endif |
12bfa3de | 140 | return dbg_reg_def[regno].name; |
82da3ff8 IM |
141 | } |
142 | ||
143 | /** | |
144 | * sleeping_thread_to_gdb_regs - Convert ptrace regs to GDB regs | |
145 | * @gdb_regs: A pointer to hold the registers in the order GDB wants. | |
146 | * @p: The &struct task_struct of the desired process. | |
147 | * | |
148 | * Convert the register values of the sleeping process in @p to | |
149 | * the format that GDB expects. | |
150 | * This function is called when kgdb does not have access to the | |
151 | * &struct pt_regs and therefore it should fill the gdb registers | |
152 | * @gdb_regs with what has been saved in &struct thread_struct | |
153 | * thread field during switch_to. | |
154 | */ | |
155 | void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p) | |
156 | { | |
703a1edc JW |
157 | #ifndef CONFIG_X86_32 |
158 | u32 *gdb_regs32 = (u32 *)gdb_regs; | |
159 | #endif | |
82da3ff8 IM |
160 | gdb_regs[GDB_AX] = 0; |
161 | gdb_regs[GDB_BX] = 0; | |
162 | gdb_regs[GDB_CX] = 0; | |
163 | gdb_regs[GDB_DX] = 0; | |
164 | gdb_regs[GDB_SI] = 0; | |
165 | gdb_regs[GDB_DI] = 0; | |
166 | gdb_regs[GDB_BP] = *(unsigned long *)p->thread.sp; | |
167 | #ifdef CONFIG_X86_32 | |
168 | gdb_regs[GDB_DS] = __KERNEL_DS; | |
169 | gdb_regs[GDB_ES] = __KERNEL_DS; | |
170 | gdb_regs[GDB_PS] = 0; | |
171 | gdb_regs[GDB_CS] = __KERNEL_CS; | |
172 | gdb_regs[GDB_PC] = p->thread.ip; | |
173 | gdb_regs[GDB_SS] = __KERNEL_DS; | |
174 | gdb_regs[GDB_FS] = 0xFFFF; | |
175 | gdb_regs[GDB_GS] = 0xFFFF; | |
176 | #else | |
703a1edc JW |
177 | gdb_regs32[GDB_PS] = *(unsigned long *)(p->thread.sp + 8); |
178 | gdb_regs32[GDB_CS] = __KERNEL_CS; | |
179 | gdb_regs32[GDB_SS] = __KERNEL_DS; | |
0c23590f | 180 | gdb_regs[GDB_PC] = 0; |
82da3ff8 IM |
181 | gdb_regs[GDB_R8] = 0; |
182 | gdb_regs[GDB_R9] = 0; | |
183 | gdb_regs[GDB_R10] = 0; | |
184 | gdb_regs[GDB_R11] = 0; | |
185 | gdb_regs[GDB_R12] = 0; | |
186 | gdb_regs[GDB_R13] = 0; | |
187 | gdb_regs[GDB_R14] = 0; | |
188 | gdb_regs[GDB_R15] = 0; | |
189 | #endif | |
190 | gdb_regs[GDB_SP] = p->thread.sp; | |
191 | } | |
192 | ||
64e9ee30 JW |
193 | static struct hw_breakpoint { |
194 | unsigned enabled; | |
64e9ee30 | 195 | unsigned long addr; |
cc096749 JW |
196 | int len; |
197 | int type; | |
8c8aefce | 198 | struct perf_event * __percpu *pev; |
df493935 | 199 | } breakinfo[HBP_NUM]; |
64e9ee30 | 200 | |
031acd8c JW |
201 | static unsigned long early_dr7; |
202 | ||
64e9ee30 JW |
203 | static void kgdb_correct_hw_break(void) |
204 | { | |
64e9ee30 JW |
205 | int breakno; |
206 | ||
df493935 | 207 | for (breakno = 0; breakno < HBP_NUM; breakno++) { |
cc096749 JW |
208 | struct perf_event *bp; |
209 | struct arch_hw_breakpoint *info; | |
210 | int val; | |
211 | int cpu = raw_smp_processor_id(); | |
212 | if (!breakinfo[breakno].enabled) | |
213 | continue; | |
031acd8c JW |
214 | if (dbg_is_early) { |
215 | set_debugreg(breakinfo[breakno].addr, breakno); | |
216 | early_dr7 |= encode_dr7(breakno, | |
217 | breakinfo[breakno].len, | |
218 | breakinfo[breakno].type); | |
219 | set_debugreg(early_dr7, 7); | |
220 | continue; | |
221 | } | |
cc096749 JW |
222 | bp = *per_cpu_ptr(breakinfo[breakno].pev, cpu); |
223 | info = counter_arch_bp(bp); | |
224 | if (bp->attr.disabled != 1) | |
225 | continue; | |
226 | bp->attr.bp_addr = breakinfo[breakno].addr; | |
227 | bp->attr.bp_len = breakinfo[breakno].len; | |
228 | bp->attr.bp_type = breakinfo[breakno].type; | |
229 | info->address = breakinfo[breakno].addr; | |
230 | info->len = breakinfo[breakno].len; | |
231 | info->type = breakinfo[breakno].type; | |
232 | val = arch_install_hw_breakpoint(bp); | |
233 | if (!val) | |
234 | bp->attr.disabled = 0; | |
64e9ee30 | 235 | } |
031acd8c JW |
236 | if (!dbg_is_early) |
237 | hw_breakpoint_restore(); | |
64e9ee30 JW |
238 | } |
239 | ||
5352ae63 JW |
240 | static int hw_break_reserve_slot(int breakno) |
241 | { | |
242 | int cpu; | |
243 | int cnt = 0; | |
244 | struct perf_event **pevent; | |
245 | ||
031acd8c JW |
246 | if (dbg_is_early) |
247 | return 0; | |
248 | ||
5352ae63 JW |
249 | for_each_online_cpu(cpu) { |
250 | cnt++; | |
251 | pevent = per_cpu_ptr(breakinfo[breakno].pev, cpu); | |
252 | if (dbg_reserve_bp_slot(*pevent)) | |
253 | goto fail; | |
254 | } | |
255 | ||
256 | return 0; | |
257 | ||
258 | fail: | |
259 | for_each_online_cpu(cpu) { | |
260 | cnt--; | |
261 | if (!cnt) | |
262 | break; | |
263 | pevent = per_cpu_ptr(breakinfo[breakno].pev, cpu); | |
264 | dbg_release_bp_slot(*pevent); | |
265 | } | |
266 | return -1; | |
267 | } | |
268 | ||
269 | static int hw_break_release_slot(int breakno) | |
270 | { | |
271 | struct perf_event **pevent; | |
272 | int cpu; | |
273 | ||
031acd8c JW |
274 | if (dbg_is_early) |
275 | return 0; | |
276 | ||
5352ae63 JW |
277 | for_each_online_cpu(cpu) { |
278 | pevent = per_cpu_ptr(breakinfo[breakno].pev, cpu); | |
279 | if (dbg_release_bp_slot(*pevent)) | |
280 | /* | |
0d2eb44f | 281 | * The debugger is responsible for handing the retry on |
5352ae63 JW |
282 | * remove failure. |
283 | */ | |
284 | return -1; | |
285 | } | |
286 | return 0; | |
287 | } | |
288 | ||
64e9ee30 JW |
289 | static int |
290 | kgdb_remove_hw_break(unsigned long addr, int len, enum kgdb_bptype bptype) | |
291 | { | |
292 | int i; | |
293 | ||
df493935 | 294 | for (i = 0; i < HBP_NUM; i++) |
64e9ee30 JW |
295 | if (breakinfo[i].addr == addr && breakinfo[i].enabled) |
296 | break; | |
df493935 | 297 | if (i == HBP_NUM) |
64e9ee30 JW |
298 | return -1; |
299 | ||
5352ae63 JW |
300 | if (hw_break_release_slot(i)) { |
301 | printk(KERN_ERR "Cannot remove hw breakpoint at %lx\n", addr); | |
302 | return -1; | |
303 | } | |
64e9ee30 JW |
304 | breakinfo[i].enabled = 0; |
305 | ||
306 | return 0; | |
307 | } | |
308 | ||
309 | static void kgdb_remove_all_hw_break(void) | |
310 | { | |
311 | int i; | |
cc096749 JW |
312 | int cpu = raw_smp_processor_id(); |
313 | struct perf_event *bp; | |
64e9ee30 | 314 | |
df493935 | 315 | for (i = 0; i < HBP_NUM; i++) { |
cc096749 JW |
316 | if (!breakinfo[i].enabled) |
317 | continue; | |
318 | bp = *per_cpu_ptr(breakinfo[i].pev, cpu); | |
10a6e676 JW |
319 | if (!bp->attr.disabled) { |
320 | arch_uninstall_hw_breakpoint(bp); | |
321 | bp->attr.disabled = 1; | |
cc096749 | 322 | continue; |
10a6e676 | 323 | } |
031acd8c JW |
324 | if (dbg_is_early) |
325 | early_dr7 &= ~encode_dr7(i, breakinfo[i].len, | |
326 | breakinfo[i].type); | |
10a6e676 JW |
327 | else if (hw_break_release_slot(i)) |
328 | printk(KERN_ERR "KGDB: hw bpt remove failed %lx\n", | |
329 | breakinfo[i].addr); | |
330 | breakinfo[i].enabled = 0; | |
cc096749 | 331 | } |
64e9ee30 JW |
332 | } |
333 | ||
334 | static int | |
335 | kgdb_set_hw_break(unsigned long addr, int len, enum kgdb_bptype bptype) | |
336 | { | |
64e9ee30 JW |
337 | int i; |
338 | ||
df493935 | 339 | for (i = 0; i < HBP_NUM; i++) |
64e9ee30 JW |
340 | if (!breakinfo[i].enabled) |
341 | break; | |
df493935 | 342 | if (i == HBP_NUM) |
64e9ee30 JW |
343 | return -1; |
344 | ||
345 | switch (bptype) { | |
346 | case BP_HARDWARE_BREAKPOINT: | |
cc096749 JW |
347 | len = 1; |
348 | breakinfo[i].type = X86_BREAKPOINT_EXECUTE; | |
64e9ee30 JW |
349 | break; |
350 | case BP_WRITE_WATCHPOINT: | |
cc096749 | 351 | breakinfo[i].type = X86_BREAKPOINT_WRITE; |
64e9ee30 JW |
352 | break; |
353 | case BP_ACCESS_WATCHPOINT: | |
cc096749 | 354 | breakinfo[i].type = X86_BREAKPOINT_RW; |
64e9ee30 JW |
355 | break; |
356 | default: | |
357 | return -1; | |
358 | } | |
cc096749 JW |
359 | switch (len) { |
360 | case 1: | |
361 | breakinfo[i].len = X86_BREAKPOINT_LEN_1; | |
362 | break; | |
363 | case 2: | |
364 | breakinfo[i].len = X86_BREAKPOINT_LEN_2; | |
365 | break; | |
366 | case 4: | |
367 | breakinfo[i].len = X86_BREAKPOINT_LEN_4; | |
368 | break; | |
369 | #ifdef CONFIG_X86_64 | |
370 | case 8: | |
371 | breakinfo[i].len = X86_BREAKPOINT_LEN_8; | |
372 | break; | |
373 | #endif | |
374 | default: | |
64e9ee30 | 375 | return -1; |
cc096749 | 376 | } |
64e9ee30 | 377 | breakinfo[i].addr = addr; |
5352ae63 JW |
378 | if (hw_break_reserve_slot(i)) { |
379 | breakinfo[i].addr = 0; | |
380 | return -1; | |
381 | } | |
cc096749 | 382 | breakinfo[i].enabled = 1; |
64e9ee30 JW |
383 | |
384 | return 0; | |
385 | } | |
386 | ||
387 | /** | |
388 | * kgdb_disable_hw_debug - Disable hardware debugging while we in kgdb. | |
389 | * @regs: Current &struct pt_regs. | |
390 | * | |
391 | * This function will be called if the particular architecture must | |
392 | * disable hardware debugging while it is processing gdb packets or | |
393 | * handling exception. | |
394 | */ | |
d7ba979d | 395 | static void kgdb_disable_hw_debug(struct pt_regs *regs) |
64e9ee30 | 396 | { |
cc096749 JW |
397 | int i; |
398 | int cpu = raw_smp_processor_id(); | |
399 | struct perf_event *bp; | |
400 | ||
64e9ee30 JW |
401 | /* Disable hardware debugging while we are in kgdb: */ |
402 | set_debugreg(0UL, 7); | |
df493935 | 403 | for (i = 0; i < HBP_NUM; i++) { |
cc096749 JW |
404 | if (!breakinfo[i].enabled) |
405 | continue; | |
031acd8c JW |
406 | if (dbg_is_early) { |
407 | early_dr7 &= ~encode_dr7(i, breakinfo[i].len, | |
408 | breakinfo[i].type); | |
409 | continue; | |
410 | } | |
cc096749 JW |
411 | bp = *per_cpu_ptr(breakinfo[i].pev, cpu); |
412 | if (bp->attr.disabled == 1) | |
413 | continue; | |
414 | arch_uninstall_hw_breakpoint(bp); | |
415 | bp->attr.disabled = 1; | |
416 | } | |
64e9ee30 JW |
417 | } |
418 | ||
82da3ff8 IM |
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; | |
82da3ff8 IM |
464 | |
465 | switch (remcomInBuffer[0]) { | |
466 | case 'c': | |
467 | case 's': | |
468 | /* try to read optional parameter, pc unchanged if no parm */ | |
469 | ptr = &remcomInBuffer[1]; | |
470 | if (kgdb_hex2long(&ptr, &addr)) | |
471 | linux_regs->ip = addr; | |
737a460f JW |
472 | case 'D': |
473 | case 'k': | |
82da3ff8 | 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 | ||
485 | return 0; | |
486 | } | |
487 | ||
488 | /* this means that we do not want to exit from the handler: */ | |
489 | return -1; | |
490 | } | |
491 | ||
492 | static inline int | |
493 | single_step_cont(struct pt_regs *regs, struct die_args *args) | |
494 | { | |
495 | /* | |
496 | * Single step exception from kernel space to user space so | |
497 | * eat the exception and continue the process: | |
498 | */ | |
499 | printk(KERN_ERR "KGDB: trap/step from kernel to user space, " | |
500 | "resuming...\n"); | |
501 | kgdb_arch_handle_exception(args->trapnr, args->signr, | |
502 | args->err, "c", "", regs); | |
62edab90 P |
503 | /* |
504 | * Reset the BS bit in dr6 (pointed by args->err) to | |
505 | * denote completion of processing | |
506 | */ | |
507 | (*(unsigned long *)ERR_PTR(args->err)) &= ~DR_STEP; | |
82da3ff8 IM |
508 | |
509 | return NOTIFY_STOP; | |
510 | } | |
511 | ||
d3597524 JW |
512 | static int was_in_debug_nmi[NR_CPUS]; |
513 | ||
9c48f1c6 | 514 | static int kgdb_nmi_handler(unsigned int cmd, struct pt_regs *regs) |
82da3ff8 | 515 | { |
82da3ff8 | 516 | switch (cmd) { |
9c48f1c6 | 517 | case NMI_LOCAL: |
82da3ff8 IM |
518 | if (atomic_read(&kgdb_active) != -1) { |
519 | /* KGDB CPU roundup */ | |
520 | kgdb_nmicallback(raw_smp_processor_id(), regs); | |
d3597524 JW |
521 | was_in_debug_nmi[raw_smp_processor_id()] = 1; |
522 | touch_nmi_watchdog(); | |
9c48f1c6 | 523 | return NMI_HANDLED; |
82da3ff8 | 524 | } |
9c48f1c6 | 525 | break; |
82da3ff8 | 526 | |
9c48f1c6 | 527 | case NMI_UNKNOWN: |
d3597524 JW |
528 | if (was_in_debug_nmi[raw_smp_processor_id()]) { |
529 | was_in_debug_nmi[raw_smp_processor_id()] = 0; | |
9c48f1c6 | 530 | return NMI_HANDLED; |
82da3ff8 | 531 | } |
9c48f1c6 DZ |
532 | break; |
533 | default: | |
534 | /* do nothing */ | |
535 | break; | |
536 | } | |
537 | return NMI_DONE; | |
538 | } | |
539 | ||
540 | static int __kgdb_notify(struct die_args *args, unsigned long cmd) | |
541 | { | |
542 | struct pt_regs *regs = args->regs; | |
82da3ff8 | 543 | |
9c48f1c6 | 544 | switch (cmd) { |
82da3ff8 | 545 | case DIE_DEBUG: |
cc096749 | 546 | if (atomic_read(&kgdb_cpu_doing_single_step) != -1) { |
d7161a65 JW |
547 | if (user_mode(regs)) |
548 | return single_step_cont(regs, args); | |
549 | break; | |
550 | } else if (test_thread_flag(TIF_SINGLESTEP)) | |
551 | /* This means a user thread is single stepping | |
552 | * a system call which should be ignored | |
553 | */ | |
554 | return NOTIFY_DONE; | |
82da3ff8 IM |
555 | /* fall through */ |
556 | default: | |
557 | if (user_mode(regs)) | |
558 | return NOTIFY_DONE; | |
559 | } | |
560 | ||
f503b5ae | 561 | if (kgdb_handle_exception(args->trapnr, args->signr, cmd, regs)) |
82da3ff8 IM |
562 | return NOTIFY_DONE; |
563 | ||
737a460f JW |
564 | /* Must touch watchdog before return to normal operation */ |
565 | touch_nmi_watchdog(); | |
82da3ff8 IM |
566 | return NOTIFY_STOP; |
567 | } | |
568 | ||
f503b5ae JW |
569 | int kgdb_ll_trap(int cmd, const char *str, |
570 | struct pt_regs *regs, long err, int trap, int sig) | |
571 | { | |
572 | struct die_args args = { | |
573 | .regs = regs, | |
574 | .str = str, | |
575 | .err = err, | |
576 | .trapnr = trap, | |
577 | .signr = sig, | |
578 | ||
579 | }; | |
580 | ||
581 | if (!kgdb_io_module_registered) | |
582 | return NOTIFY_DONE; | |
583 | ||
584 | return __kgdb_notify(&args, cmd); | |
585 | } | |
f503b5ae | 586 | |
82da3ff8 IM |
587 | static int |
588 | kgdb_notify(struct notifier_block *self, unsigned long cmd, void *ptr) | |
589 | { | |
590 | unsigned long flags; | |
591 | int ret; | |
592 | ||
593 | local_irq_save(flags); | |
594 | ret = __kgdb_notify(ptr, cmd); | |
595 | local_irq_restore(flags); | |
596 | ||
597 | return ret; | |
598 | } | |
599 | ||
600 | static struct notifier_block kgdb_notifier = { | |
601 | .notifier_call = kgdb_notify, | |
82da3ff8 IM |
602 | }; |
603 | ||
604 | /** | |
605 | * kgdb_arch_init - Perform any architecture specific initalization. | |
606 | * | |
607 | * This function will handle the initalization of any architecture | |
608 | * specific callbacks. | |
609 | */ | |
610 | int kgdb_arch_init(void) | |
0b4b3827 | 611 | { |
9c48f1c6 DZ |
612 | int retval; |
613 | ||
614 | retval = register_die_notifier(&kgdb_notifier); | |
615 | if (retval) | |
616 | goto out; | |
617 | ||
618 | retval = register_nmi_handler(NMI_LOCAL, kgdb_nmi_handler, | |
619 | 0, "kgdb"); | |
620 | if (retval) | |
621 | goto out1; | |
622 | ||
623 | retval = register_nmi_handler(NMI_UNKNOWN, kgdb_nmi_handler, | |
624 | 0, "kgdb"); | |
625 | ||
626 | if (retval) | |
627 | goto out2; | |
628 | ||
629 | return retval; | |
630 | ||
631 | out2: | |
632 | unregister_nmi_handler(NMI_LOCAL, "kgdb"); | |
633 | out1: | |
634 | unregister_die_notifier(&kgdb_notifier); | |
635 | out: | |
636 | return retval; | |
0b4b3827 JW |
637 | } |
638 | ||
a8b0ca17 | 639 | static void kgdb_hw_overflow_handler(struct perf_event *event, |
ba773f7c JW |
640 | struct perf_sample_data *data, struct pt_regs *regs) |
641 | { | |
fad99fac JW |
642 | struct task_struct *tsk = current; |
643 | int i; | |
644 | ||
645 | for (i = 0; i < 4; i++) | |
646 | if (breakinfo[i].enabled) | |
647 | tsk->thread.debugreg6 |= (DR_TRAP0 << i); | |
ba773f7c JW |
648 | } |
649 | ||
0b4b3827 | 650 | void kgdb_arch_late(void) |
82da3ff8 | 651 | { |
cc096749 | 652 | int i, cpu; |
cc096749 JW |
653 | struct perf_event_attr attr; |
654 | struct perf_event **pevent; | |
655 | ||
cc096749 JW |
656 | /* |
657 | * Pre-allocate the hw breakpoint structions in the non-atomic | |
658 | * portion of kgdb because this operation requires mutexs to | |
659 | * complete. | |
660 | */ | |
ab310b5e | 661 | hw_breakpoint_init(&attr); |
cc096749 | 662 | attr.bp_addr = (unsigned long)kgdb_arch_init; |
cc096749 JW |
663 | attr.bp_len = HW_BREAKPOINT_LEN_1; |
664 | attr.bp_type = HW_BREAKPOINT_W; | |
665 | attr.disabled = 1; | |
df493935 | 666 | for (i = 0; i < HBP_NUM; i++) { |
0b4b3827 JW |
667 | if (breakinfo[i].pev) |
668 | continue; | |
4dc0da86 | 669 | breakinfo[i].pev = register_wide_hw_breakpoint(&attr, NULL, NULL); |
91b152aa | 670 | if (IS_ERR((void * __force)breakinfo[i].pev)) { |
0b4b3827 JW |
671 | printk(KERN_ERR "kgdb: Could not allocate hw" |
672 | "breakpoints\nDisabling the kernel debugger\n"); | |
cc096749 JW |
673 | breakinfo[i].pev = NULL; |
674 | kgdb_arch_exit(); | |
0b4b3827 | 675 | return; |
cc096749 JW |
676 | } |
677 | for_each_online_cpu(cpu) { | |
678 | pevent = per_cpu_ptr(breakinfo[i].pev, cpu); | |
679 | pevent[0]->hw.sample_period = 1; | |
ba773f7c | 680 | pevent[0]->overflow_handler = kgdb_hw_overflow_handler; |
cc096749 JW |
681 | if (pevent[0]->destroy != NULL) { |
682 | pevent[0]->destroy = NULL; | |
683 | release_bp_slot(*pevent); | |
684 | } | |
685 | } | |
686 | } | |
82da3ff8 IM |
687 | } |
688 | ||
689 | /** | |
690 | * kgdb_arch_exit - Perform any architecture specific uninitalization. | |
691 | * | |
692 | * This function will handle the uninitalization of any architecture | |
693 | * specific callbacks, for dynamic registration and unregistration. | |
694 | */ | |
695 | void kgdb_arch_exit(void) | |
696 | { | |
cc096749 JW |
697 | int i; |
698 | for (i = 0; i < 4; i++) { | |
699 | if (breakinfo[i].pev) { | |
700 | unregister_wide_hw_breakpoint(breakinfo[i].pev); | |
701 | breakinfo[i].pev = NULL; | |
702 | } | |
703 | } | |
9c48f1c6 DZ |
704 | unregister_nmi_handler(NMI_UNKNOWN, "kgdb"); |
705 | unregister_nmi_handler(NMI_LOCAL, "kgdb"); | |
82da3ff8 IM |
706 | unregister_die_notifier(&kgdb_notifier); |
707 | } | |
708 | ||
709 | /** | |
710 | * | |
711 | * kgdb_skipexception - Bail out of KGDB when we've been triggered. | |
712 | * @exception: Exception vector number | |
713 | * @regs: Current &struct pt_regs. | |
714 | * | |
715 | * On some architectures we need to skip a breakpoint exception when | |
716 | * it occurs after a breakpoint has been removed. | |
717 | * | |
718 | * Skip an int3 exception when it occurs after a breakpoint has been | |
719 | * removed. Backtrack eip by 1 since the int3 would have caused it to | |
720 | * increment by 1. | |
721 | */ | |
722 | int kgdb_skipexception(int exception, struct pt_regs *regs) | |
723 | { | |
724 | if (exception == 3 && kgdb_isremovedbreak(regs->ip - 1)) { | |
725 | regs->ip -= 1; | |
726 | return 1; | |
727 | } | |
728 | return 0; | |
729 | } | |
730 | ||
731 | unsigned long kgdb_arch_pc(int exception, struct pt_regs *regs) | |
732 | { | |
733 | if (exception == 3) | |
734 | return instruction_pointer(regs) - 1; | |
735 | return instruction_pointer(regs); | |
736 | } | |
737 | ||
dcc78711 JW |
738 | void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long ip) |
739 | { | |
740 | regs->ip = ip; | |
741 | } | |
742 | ||
82da3ff8 IM |
743 | struct kgdb_arch arch_kgdb_ops = { |
744 | /* Breakpoint instruction: */ | |
745 | .gdb_bpt_instr = { 0xcc }, | |
64e9ee30 JW |
746 | .flags = KGDB_HW_BREAKPOINT, |
747 | .set_hw_breakpoint = kgdb_set_hw_break, | |
748 | .remove_hw_breakpoint = kgdb_remove_hw_break, | |
d7ba979d | 749 | .disable_hw_break = kgdb_disable_hw_debug, |
64e9ee30 JW |
750 | .remove_all_hw_break = kgdb_remove_all_hw_break, |
751 | .correct_hw_break = kgdb_correct_hw_break, | |
82da3ff8 | 752 | }; |