1 | // SPDX-License-Identifier: GPL-2.0-or-later |
2 | /* |
3 | */ |
4 | |
5 | /* |
6 | * Copyright (C) 2004 Amit S. Kale <amitkale@linsyssoft.com> |
7 | * Copyright (C) 2000-2001 VERITAS Software Corporation. |
8 | * Copyright (C) 2002 Andi Kleen, SuSE Labs |
9 | * Copyright (C) 2004 LinSysSoft Technologies Pvt. Ltd. |
10 | * Copyright (C) 2007 MontaVista Software, Inc. |
11 | * Copyright (C) 2007-2008 Jason Wessel, Wind River Systems, Inc. |
12 | */ |
13 | /**************************************************************************** |
14 | * Contributor: Lake Stevens Instrument Division$ |
15 | * Written by: Glenn Engel $ |
16 | * Updated by: Amit Kale<akale@veritas.com> |
17 | * Updated by: Tom Rini <trini@kernel.crashing.org> |
18 | * Updated by: Jason Wessel <jason.wessel@windriver.com> |
19 | * Modified for 386 by Jim Kingdon, Cygnus Support. |
20 | * Original kgdb, compatibility with 2.1.xx kernel by |
21 | * David Grothe <dave@gcom.com> |
22 | * Integrated into 2.2.5 kernel by Tigran Aivazian <tigran@sco.com> |
23 | * X86_64 changes from Andi Kleen's patch merged by Jim Houston |
24 | */ |
25 | #include <linux/spinlock.h> |
26 | #include <linux/kdebug.h> |
27 | #include <linux/string.h> |
28 | #include <linux/kernel.h> |
29 | #include <linux/ptrace.h> |
30 | #include <linux/sched.h> |
31 | #include <linux/delay.h> |
32 | #include <linux/kgdb.h> |
33 | #include <linux/smp.h> |
34 | #include <linux/nmi.h> |
35 | #include <linux/hw_breakpoint.h> |
36 | #include <linux/uaccess.h> |
37 | #include <linux/memory.h> |
38 | |
39 | #include <asm/text-patching.h> |
40 | #include <asm/debugreg.h> |
41 | #include <asm/apicdef.h> |
42 | #include <asm/apic.h> |
43 | #include <asm/nmi.h> |
44 | #include <asm/switch_to.h> |
45 | |
46 | struct dbg_reg_def_t dbg_reg_def[DBG_MAX_REG_NUM] = |
47 | { |
48 | #ifdef CONFIG_X86_32 |
49 | { "ax" , 4, offsetof(struct pt_regs, ax) }, |
50 | { "cx" , 4, offsetof(struct pt_regs, cx) }, |
51 | { "dx" , 4, offsetof(struct pt_regs, dx) }, |
52 | { "bx" , 4, offsetof(struct pt_regs, bx) }, |
53 | { "sp" , 4, offsetof(struct pt_regs, sp) }, |
54 | { "bp" , 4, offsetof(struct pt_regs, bp) }, |
55 | { "si" , 4, offsetof(struct pt_regs, si) }, |
56 | { "di" , 4, offsetof(struct pt_regs, di) }, |
57 | { "ip" , 4, offsetof(struct pt_regs, ip) }, |
58 | { "flags" , 4, offsetof(struct pt_regs, flags) }, |
59 | { "cs" , 4, offsetof(struct pt_regs, cs) }, |
60 | { "ss" , 4, offsetof(struct pt_regs, ss) }, |
61 | { "ds" , 4, offsetof(struct pt_regs, ds) }, |
62 | { "es" , 4, offsetof(struct pt_regs, es) }, |
63 | #else |
64 | { "ax" , 8, offsetof(struct pt_regs, ax) }, |
65 | { "bx" , 8, offsetof(struct pt_regs, bx) }, |
66 | { "cx" , 8, offsetof(struct pt_regs, cx) }, |
67 | { "dx" , 8, offsetof(struct pt_regs, dx) }, |
68 | { "si" , 8, offsetof(struct pt_regs, si) }, |
69 | { "di" , 8, offsetof(struct pt_regs, di) }, |
70 | { "bp" , 8, offsetof(struct pt_regs, bp) }, |
71 | { "sp" , 8, offsetof(struct pt_regs, sp) }, |
72 | { "r8" , 8, offsetof(struct pt_regs, r8) }, |
73 | { "r9" , 8, offsetof(struct pt_regs, r9) }, |
74 | { "r10" , 8, offsetof(struct pt_regs, r10) }, |
75 | { "r11" , 8, offsetof(struct pt_regs, r11) }, |
76 | { "r12" , 8, offsetof(struct pt_regs, r12) }, |
77 | { "r13" , 8, offsetof(struct pt_regs, r13) }, |
78 | { "r14" , 8, offsetof(struct pt_regs, r14) }, |
79 | { "r15" , 8, offsetof(struct pt_regs, r15) }, |
80 | { "ip" , 8, offsetof(struct pt_regs, ip) }, |
81 | { "flags" , 4, offsetof(struct pt_regs, flags) }, |
82 | { "cs" , 4, offsetof(struct pt_regs, cs) }, |
83 | { "ss" , 4, offsetof(struct pt_regs, ss) }, |
84 | { "ds" , 4, -1 }, |
85 | { "es" , 4, -1 }, |
86 | #endif |
87 | { "fs" , 4, -1 }, |
88 | { "gs" , 4, -1 }, |
89 | }; |
90 | |
91 | int dbg_set_reg(int regno, void *mem, struct pt_regs *regs) |
92 | { |
93 | if ( |
94 | #ifdef CONFIG_X86_32 |
95 | regno == GDB_SS || regno == GDB_FS || regno == GDB_GS || |
96 | #endif |
97 | regno == GDB_SP || regno == GDB_ORIG_AX) |
98 | return 0; |
99 | |
100 | if (dbg_reg_def[regno].offset != -1) |
101 | memcpy((void *)regs + dbg_reg_def[regno].offset, mem, |
102 | dbg_reg_def[regno].size); |
103 | return 0; |
104 | } |
105 | |
106 | char *dbg_get_reg(int regno, void *mem, struct pt_regs *regs) |
107 | { |
108 | if (regno == GDB_ORIG_AX) { |
109 | memcpy(mem, ®s->orig_ax, sizeof(regs->orig_ax)); |
110 | return "orig_ax" ; |
111 | } |
112 | if (regno >= DBG_MAX_REG_NUM || regno < 0) |
113 | return NULL; |
114 | |
115 | if (dbg_reg_def[regno].offset != -1) |
116 | memcpy(mem, (void *)regs + dbg_reg_def[regno].offset, |
117 | dbg_reg_def[regno].size); |
118 | |
119 | #ifdef CONFIG_X86_32 |
120 | switch (regno) { |
121 | case GDB_GS: |
122 | case GDB_FS: |
123 | *(unsigned long *)mem = 0xFFFF; |
124 | break; |
125 | } |
126 | #endif |
127 | return dbg_reg_def[regno].name; |
128 | } |
129 | |
130 | /** |
131 | * sleeping_thread_to_gdb_regs - Convert ptrace regs to GDB regs |
132 | * @gdb_regs: A pointer to hold the registers in the order GDB wants. |
133 | * @p: The &struct task_struct of the desired process. |
134 | * |
135 | * Convert the register values of the sleeping process in @p to |
136 | * the format that GDB expects. |
137 | * This function is called when kgdb does not have access to the |
138 | * &struct pt_regs and therefore it should fill the gdb registers |
139 | * @gdb_regs with what has been saved in &struct thread_struct |
140 | * thread field during switch_to. |
141 | */ |
142 | void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p) |
143 | { |
144 | #ifndef CONFIG_X86_32 |
145 | u32 *gdb_regs32 = (u32 *)gdb_regs; |
146 | #endif |
147 | gdb_regs[GDB_AX] = 0; |
148 | gdb_regs[GDB_BX] = 0; |
149 | gdb_regs[GDB_CX] = 0; |
150 | gdb_regs[GDB_DX] = 0; |
151 | gdb_regs[GDB_SI] = 0; |
152 | gdb_regs[GDB_DI] = 0; |
153 | gdb_regs[GDB_BP] = ((struct inactive_task_frame *)p->thread.sp)->bp; |
154 | #ifdef CONFIG_X86_32 |
155 | gdb_regs[GDB_DS] = __KERNEL_DS; |
156 | gdb_regs[GDB_ES] = __KERNEL_DS; |
157 | gdb_regs[GDB_PS] = 0; |
158 | gdb_regs[GDB_CS] = __KERNEL_CS; |
159 | gdb_regs[GDB_SS] = __KERNEL_DS; |
160 | gdb_regs[GDB_FS] = 0xFFFF; |
161 | gdb_regs[GDB_GS] = 0xFFFF; |
162 | #else |
163 | gdb_regs32[GDB_PS] = 0; |
164 | gdb_regs32[GDB_CS] = __KERNEL_CS; |
165 | gdb_regs32[GDB_SS] = __KERNEL_DS; |
166 | gdb_regs[GDB_R8] = 0; |
167 | gdb_regs[GDB_R9] = 0; |
168 | gdb_regs[GDB_R10] = 0; |
169 | gdb_regs[GDB_R11] = 0; |
170 | gdb_regs[GDB_R12] = 0; |
171 | gdb_regs[GDB_R13] = 0; |
172 | gdb_regs[GDB_R14] = 0; |
173 | gdb_regs[GDB_R15] = 0; |
174 | #endif |
175 | gdb_regs[GDB_PC] = 0; |
176 | gdb_regs[GDB_SP] = p->thread.sp; |
177 | } |
178 | |
179 | static struct hw_breakpoint { |
180 | unsigned enabled; |
181 | unsigned long addr; |
182 | int len; |
183 | int type; |
184 | struct perf_event * __percpu *pev; |
185 | } breakinfo[HBP_NUM]; |
186 | |
187 | static unsigned long early_dr7; |
188 | |
189 | static void kgdb_correct_hw_break(void) |
190 | { |
191 | int breakno; |
192 | |
193 | for (breakno = 0; breakno < HBP_NUM; breakno++) { |
194 | struct perf_event *bp; |
195 | struct arch_hw_breakpoint *info; |
196 | int val; |
197 | int cpu = raw_smp_processor_id(); |
198 | if (!breakinfo[breakno].enabled) |
199 | continue; |
200 | if (dbg_is_early) { |
201 | set_debugreg(val: breakinfo[breakno].addr, reg: breakno); |
202 | early_dr7 |= encode_dr7(drnum: breakno, |
203 | len: breakinfo[breakno].len, |
204 | type: breakinfo[breakno].type); |
205 | set_debugreg(val: early_dr7, reg: 7); |
206 | continue; |
207 | } |
208 | bp = *per_cpu_ptr(breakinfo[breakno].pev, cpu); |
209 | info = counter_arch_bp(bp); |
210 | if (bp->attr.disabled != 1) |
211 | continue; |
212 | bp->attr.bp_addr = breakinfo[breakno].addr; |
213 | bp->attr.bp_len = breakinfo[breakno].len; |
214 | bp->attr.bp_type = breakinfo[breakno].type; |
215 | info->address = breakinfo[breakno].addr; |
216 | info->len = breakinfo[breakno].len; |
217 | info->type = breakinfo[breakno].type; |
218 | val = arch_install_hw_breakpoint(bp); |
219 | if (!val) |
220 | bp->attr.disabled = 0; |
221 | } |
222 | if (!dbg_is_early) |
223 | hw_breakpoint_restore(); |
224 | } |
225 | |
226 | static int hw_break_reserve_slot(int breakno) |
227 | { |
228 | int cpu; |
229 | int cnt = 0; |
230 | struct perf_event **pevent; |
231 | |
232 | if (dbg_is_early) |
233 | return 0; |
234 | |
235 | for_each_online_cpu(cpu) { |
236 | cnt++; |
237 | pevent = per_cpu_ptr(breakinfo[breakno].pev, cpu); |
238 | if (dbg_reserve_bp_slot(bp: *pevent)) |
239 | goto fail; |
240 | } |
241 | |
242 | return 0; |
243 | |
244 | fail: |
245 | for_each_online_cpu(cpu) { |
246 | cnt--; |
247 | if (!cnt) |
248 | break; |
249 | pevent = per_cpu_ptr(breakinfo[breakno].pev, cpu); |
250 | dbg_release_bp_slot(bp: *pevent); |
251 | } |
252 | return -1; |
253 | } |
254 | |
255 | static int hw_break_release_slot(int breakno) |
256 | { |
257 | struct perf_event **pevent; |
258 | int cpu; |
259 | |
260 | if (dbg_is_early) |
261 | return 0; |
262 | |
263 | for_each_online_cpu(cpu) { |
264 | pevent = per_cpu_ptr(breakinfo[breakno].pev, cpu); |
265 | if (dbg_release_bp_slot(bp: *pevent)) |
266 | /* |
267 | * The debugger is responsible for handing the retry on |
268 | * remove failure. |
269 | */ |
270 | return -1; |
271 | } |
272 | return 0; |
273 | } |
274 | |
275 | static int |
276 | kgdb_remove_hw_break(unsigned long addr, int len, enum kgdb_bptype bptype) |
277 | { |
278 | int i; |
279 | |
280 | for (i = 0; i < HBP_NUM; i++) |
281 | if (breakinfo[i].addr == addr && breakinfo[i].enabled) |
282 | break; |
283 | if (i == HBP_NUM) |
284 | return -1; |
285 | |
286 | if (hw_break_release_slot(breakno: i)) { |
287 | printk(KERN_ERR "Cannot remove hw breakpoint at %lx\n" , addr); |
288 | return -1; |
289 | } |
290 | breakinfo[i].enabled = 0; |
291 | |
292 | return 0; |
293 | } |
294 | |
295 | static void kgdb_remove_all_hw_break(void) |
296 | { |
297 | int i; |
298 | int cpu = raw_smp_processor_id(); |
299 | struct perf_event *bp; |
300 | |
301 | for (i = 0; i < HBP_NUM; i++) { |
302 | if (!breakinfo[i].enabled) |
303 | continue; |
304 | bp = *per_cpu_ptr(breakinfo[i].pev, cpu); |
305 | if (!bp->attr.disabled) { |
306 | arch_uninstall_hw_breakpoint(bp); |
307 | bp->attr.disabled = 1; |
308 | continue; |
309 | } |
310 | if (dbg_is_early) |
311 | early_dr7 &= ~encode_dr7(drnum: i, len: breakinfo[i].len, |
312 | type: breakinfo[i].type); |
313 | else if (hw_break_release_slot(breakno: i)) |
314 | printk(KERN_ERR "KGDB: hw bpt remove failed %lx\n" , |
315 | breakinfo[i].addr); |
316 | breakinfo[i].enabled = 0; |
317 | } |
318 | } |
319 | |
320 | static int |
321 | kgdb_set_hw_break(unsigned long addr, int len, enum kgdb_bptype bptype) |
322 | { |
323 | int i; |
324 | |
325 | for (i = 0; i < HBP_NUM; i++) |
326 | if (!breakinfo[i].enabled) |
327 | break; |
328 | if (i == HBP_NUM) |
329 | return -1; |
330 | |
331 | switch (bptype) { |
332 | case BP_HARDWARE_BREAKPOINT: |
333 | len = 1; |
334 | breakinfo[i].type = X86_BREAKPOINT_EXECUTE; |
335 | break; |
336 | case BP_WRITE_WATCHPOINT: |
337 | breakinfo[i].type = X86_BREAKPOINT_WRITE; |
338 | break; |
339 | case BP_ACCESS_WATCHPOINT: |
340 | breakinfo[i].type = X86_BREAKPOINT_RW; |
341 | break; |
342 | default: |
343 | return -1; |
344 | } |
345 | switch (len) { |
346 | case 1: |
347 | breakinfo[i].len = X86_BREAKPOINT_LEN_1; |
348 | break; |
349 | case 2: |
350 | breakinfo[i].len = X86_BREAKPOINT_LEN_2; |
351 | break; |
352 | case 4: |
353 | breakinfo[i].len = X86_BREAKPOINT_LEN_4; |
354 | break; |
355 | #ifdef CONFIG_X86_64 |
356 | case 8: |
357 | breakinfo[i].len = X86_BREAKPOINT_LEN_8; |
358 | break; |
359 | #endif |
360 | default: |
361 | return -1; |
362 | } |
363 | breakinfo[i].addr = addr; |
364 | if (hw_break_reserve_slot(breakno: i)) { |
365 | breakinfo[i].addr = 0; |
366 | return -1; |
367 | } |
368 | breakinfo[i].enabled = 1; |
369 | |
370 | return 0; |
371 | } |
372 | |
373 | /** |
374 | * kgdb_disable_hw_debug - Disable hardware debugging while we in kgdb. |
375 | * @regs: Current &struct pt_regs. |
376 | * |
377 | * This function will be called if the particular architecture must |
378 | * disable hardware debugging while it is processing gdb packets or |
379 | * handling exception. |
380 | */ |
381 | static void kgdb_disable_hw_debug(struct pt_regs *regs) |
382 | { |
383 | int i; |
384 | int cpu = raw_smp_processor_id(); |
385 | struct perf_event *bp; |
386 | |
387 | /* Disable hardware debugging while we are in kgdb: */ |
388 | set_debugreg(val: 0UL, reg: 7); |
389 | for (i = 0; i < HBP_NUM; i++) { |
390 | if (!breakinfo[i].enabled) |
391 | continue; |
392 | if (dbg_is_early) { |
393 | early_dr7 &= ~encode_dr7(drnum: i, len: breakinfo[i].len, |
394 | type: breakinfo[i].type); |
395 | continue; |
396 | } |
397 | bp = *per_cpu_ptr(breakinfo[i].pev, cpu); |
398 | if (bp->attr.disabled == 1) |
399 | continue; |
400 | arch_uninstall_hw_breakpoint(bp); |
401 | bp->attr.disabled = 1; |
402 | } |
403 | } |
404 | |
405 | #ifdef CONFIG_SMP |
406 | /** |
407 | * kgdb_roundup_cpus - Get other CPUs into a holding pattern |
408 | * |
409 | * On SMP systems, we need to get the attention of the other CPUs |
410 | * and get them be in a known state. This should do what is needed |
411 | * to get the other CPUs to call kgdb_wait(). Note that on some arches, |
412 | * the NMI approach is not used for rounding up all the CPUs. For example, |
413 | * in case of MIPS, smp_call_function() is used to roundup CPUs. |
414 | * |
415 | * On non-SMP systems, this is not called. |
416 | */ |
417 | void kgdb_roundup_cpus(void) |
418 | { |
419 | apic_send_IPI_allbutself(NMI_VECTOR); |
420 | } |
421 | #endif |
422 | |
423 | /** |
424 | * kgdb_arch_handle_exception - Handle architecture specific GDB packets. |
425 | * @e_vector: The error vector of the exception that happened. |
426 | * @signo: The signal number of the exception that happened. |
427 | * @err_code: The error code of the exception that happened. |
428 | * @remcomInBuffer: The buffer of the packet we have read. |
429 | * @remcomOutBuffer: The buffer of %BUFMAX bytes to write a packet into. |
430 | * @linux_regs: The &struct pt_regs of the current process. |
431 | * |
432 | * This function MUST handle the 'c' and 's' command packets, |
433 | * as well packets to set / remove a hardware breakpoint, if used. |
434 | * If there are additional packets which the hardware needs to handle, |
435 | * they are handled here. The code should return -1 if it wants to |
436 | * process more packets, and a %0 or %1 if it wants to exit from the |
437 | * kgdb callback. |
438 | */ |
439 | int kgdb_arch_handle_exception(int e_vector, int signo, int err_code, |
440 | char *remcomInBuffer, char *remcomOutBuffer, |
441 | struct pt_regs *linux_regs) |
442 | { |
443 | unsigned long addr; |
444 | char *ptr; |
445 | |
446 | switch (remcomInBuffer[0]) { |
447 | case 'c': |
448 | case 's': |
449 | /* try to read optional parameter, pc unchanged if no parm */ |
450 | ptr = &remcomInBuffer[1]; |
451 | if (kgdb_hex2long(ptr: &ptr, long_val: &addr)) |
452 | linux_regs->ip = addr; |
453 | fallthrough; |
454 | case 'D': |
455 | case 'k': |
456 | /* clear the trace bit */ |
457 | linux_regs->flags &= ~X86_EFLAGS_TF; |
458 | atomic_set(v: &kgdb_cpu_doing_single_step, i: -1); |
459 | |
460 | /* set the trace bit if we're stepping */ |
461 | if (remcomInBuffer[0] == 's') { |
462 | linux_regs->flags |= X86_EFLAGS_TF; |
463 | atomic_set(v: &kgdb_cpu_doing_single_step, |
464 | raw_smp_processor_id()); |
465 | } |
466 | |
467 | return 0; |
468 | } |
469 | |
470 | /* this means that we do not want to exit from the handler: */ |
471 | return -1; |
472 | } |
473 | |
474 | static inline int |
475 | single_step_cont(struct pt_regs *regs, struct die_args *args) |
476 | { |
477 | /* |
478 | * Single step exception from kernel space to user space so |
479 | * eat the exception and continue the process: |
480 | */ |
481 | printk(KERN_ERR "KGDB: trap/step from kernel to user space, " |
482 | "resuming...\n" ); |
483 | kgdb_arch_handle_exception(e_vector: args->trapnr, signo: args->signr, |
484 | err_code: args->err, remcomInBuffer: "c" , remcomOutBuffer: "" , linux_regs: regs); |
485 | /* |
486 | * Reset the BS bit in dr6 (pointed by args->err) to |
487 | * denote completion of processing |
488 | */ |
489 | (*(unsigned long *)ERR_PTR(error: args->err)) &= ~DR_STEP; |
490 | |
491 | return NOTIFY_STOP; |
492 | } |
493 | |
494 | static DECLARE_BITMAP(was_in_debug_nmi, NR_CPUS); |
495 | |
496 | static int kgdb_nmi_handler(unsigned int cmd, struct pt_regs *regs) |
497 | { |
498 | int cpu; |
499 | |
500 | switch (cmd) { |
501 | case NMI_LOCAL: |
502 | if (atomic_read(v: &kgdb_active) != -1) { |
503 | /* KGDB CPU roundup */ |
504 | cpu = raw_smp_processor_id(); |
505 | kgdb_nmicallback(cpu, regs); |
506 | set_bit(nr: cpu, addr: was_in_debug_nmi); |
507 | touch_nmi_watchdog(); |
508 | |
509 | return NMI_HANDLED; |
510 | } |
511 | break; |
512 | |
513 | case NMI_UNKNOWN: |
514 | cpu = raw_smp_processor_id(); |
515 | |
516 | if (__test_and_clear_bit(cpu, was_in_debug_nmi)) |
517 | return NMI_HANDLED; |
518 | |
519 | break; |
520 | default: |
521 | /* do nothing */ |
522 | break; |
523 | } |
524 | return NMI_DONE; |
525 | } |
526 | |
527 | static int __kgdb_notify(struct die_args *args, unsigned long cmd) |
528 | { |
529 | struct pt_regs *regs = args->regs; |
530 | |
531 | switch (cmd) { |
532 | case DIE_DEBUG: |
533 | if (atomic_read(v: &kgdb_cpu_doing_single_step) != -1) { |
534 | if (user_mode(regs)) |
535 | return single_step_cont(regs, args); |
536 | break; |
537 | } else if (test_thread_flag(TIF_SINGLESTEP)) |
538 | /* This means a user thread is single stepping |
539 | * a system call which should be ignored |
540 | */ |
541 | return NOTIFY_DONE; |
542 | fallthrough; |
543 | default: |
544 | if (user_mode(regs)) |
545 | return NOTIFY_DONE; |
546 | } |
547 | |
548 | if (kgdb_handle_exception(ex_vector: args->trapnr, signo: args->signr, err_code: cmd, regs)) |
549 | return NOTIFY_DONE; |
550 | |
551 | /* Must touch watchdog before return to normal operation */ |
552 | touch_nmi_watchdog(); |
553 | return NOTIFY_STOP; |
554 | } |
555 | |
556 | int kgdb_ll_trap(int cmd, const char *str, |
557 | struct pt_regs *regs, long err, int trap, int sig) |
558 | { |
559 | struct die_args args = { |
560 | .regs = regs, |
561 | .str = str, |
562 | .err = err, |
563 | .trapnr = trap, |
564 | .signr = sig, |
565 | |
566 | }; |
567 | |
568 | if (!kgdb_io_module_registered) |
569 | return NOTIFY_DONE; |
570 | |
571 | return __kgdb_notify(args: &args, cmd); |
572 | } |
573 | |
574 | static int |
575 | kgdb_notify(struct notifier_block *self, unsigned long cmd, void *ptr) |
576 | { |
577 | unsigned long flags; |
578 | int ret; |
579 | |
580 | local_irq_save(flags); |
581 | ret = __kgdb_notify(args: ptr, cmd); |
582 | local_irq_restore(flags); |
583 | |
584 | return ret; |
585 | } |
586 | |
587 | static struct notifier_block kgdb_notifier = { |
588 | .notifier_call = kgdb_notify, |
589 | }; |
590 | |
591 | /** |
592 | * kgdb_arch_init - Perform any architecture specific initialization. |
593 | * |
594 | * This function will handle the initialization of any architecture |
595 | * specific callbacks. |
596 | */ |
597 | int kgdb_arch_init(void) |
598 | { |
599 | int retval; |
600 | |
601 | retval = register_die_notifier(nb: &kgdb_notifier); |
602 | if (retval) |
603 | goto out; |
604 | |
605 | retval = register_nmi_handler(NMI_LOCAL, kgdb_nmi_handler, |
606 | 0, "kgdb" ); |
607 | if (retval) |
608 | goto out1; |
609 | |
610 | retval = register_nmi_handler(NMI_UNKNOWN, kgdb_nmi_handler, |
611 | 0, "kgdb" ); |
612 | |
613 | if (retval) |
614 | goto out2; |
615 | |
616 | return retval; |
617 | |
618 | out2: |
619 | unregister_nmi_handler(NMI_LOCAL, "kgdb" ); |
620 | out1: |
621 | unregister_die_notifier(nb: &kgdb_notifier); |
622 | out: |
623 | return retval; |
624 | } |
625 | |
626 | static void kgdb_hw_overflow_handler(struct perf_event *event, |
627 | struct perf_sample_data *data, struct pt_regs *regs) |
628 | { |
629 | struct task_struct *tsk = current; |
630 | int i; |
631 | |
632 | for (i = 0; i < 4; i++) { |
633 | if (breakinfo[i].enabled) |
634 | tsk->thread.virtual_dr6 |= (DR_TRAP0 << i); |
635 | } |
636 | } |
637 | |
638 | void kgdb_arch_late(void) |
639 | { |
640 | int i, cpu; |
641 | struct perf_event_attr attr; |
642 | struct perf_event **pevent; |
643 | |
644 | /* |
645 | * Pre-allocate the hw breakpoint instructions in the non-atomic |
646 | * portion of kgdb because this operation requires mutexs to |
647 | * complete. |
648 | */ |
649 | hw_breakpoint_init(attr: &attr); |
650 | attr.bp_addr = (unsigned long)kgdb_arch_init; |
651 | attr.bp_len = HW_BREAKPOINT_LEN_1; |
652 | attr.bp_type = HW_BREAKPOINT_W; |
653 | attr.disabled = 1; |
654 | for (i = 0; i < HBP_NUM; i++) { |
655 | if (breakinfo[i].pev) |
656 | continue; |
657 | breakinfo[i].pev = register_wide_hw_breakpoint(attr: &attr, NULL, NULL); |
658 | if (IS_ERR(ptr: (void * __force)breakinfo[i].pev)) { |
659 | printk(KERN_ERR "kgdb: Could not allocate hw" |
660 | "breakpoints\nDisabling the kernel debugger\n" ); |
661 | breakinfo[i].pev = NULL; |
662 | kgdb_arch_exit(); |
663 | return; |
664 | } |
665 | for_each_online_cpu(cpu) { |
666 | pevent = per_cpu_ptr(breakinfo[i].pev, cpu); |
667 | pevent[0]->hw.sample_period = 1; |
668 | pevent[0]->overflow_handler = kgdb_hw_overflow_handler; |
669 | if (pevent[0]->destroy != NULL) { |
670 | pevent[0]->destroy = NULL; |
671 | release_bp_slot(bp: *pevent); |
672 | } |
673 | } |
674 | } |
675 | } |
676 | |
677 | /** |
678 | * kgdb_arch_exit - Perform any architecture specific uninitalization. |
679 | * |
680 | * This function will handle the uninitalization of any architecture |
681 | * specific callbacks, for dynamic registration and unregistration. |
682 | */ |
683 | void kgdb_arch_exit(void) |
684 | { |
685 | int i; |
686 | for (i = 0; i < 4; i++) { |
687 | if (breakinfo[i].pev) { |
688 | unregister_wide_hw_breakpoint(cpu_events: breakinfo[i].pev); |
689 | breakinfo[i].pev = NULL; |
690 | } |
691 | } |
692 | unregister_nmi_handler(NMI_UNKNOWN, "kgdb" ); |
693 | unregister_nmi_handler(NMI_LOCAL, "kgdb" ); |
694 | unregister_die_notifier(nb: &kgdb_notifier); |
695 | } |
696 | |
697 | /** |
698 | * kgdb_skipexception - Bail out of KGDB when we've been triggered. |
699 | * @exception: Exception vector number |
700 | * @regs: Current &struct pt_regs. |
701 | * |
702 | * On some architectures we need to skip a breakpoint exception when |
703 | * it occurs after a breakpoint has been removed. |
704 | * |
705 | * Skip an int3 exception when it occurs after a breakpoint has been |
706 | * removed. Backtrack eip by 1 since the int3 would have caused it to |
707 | * increment by 1. |
708 | */ |
709 | int kgdb_skipexception(int exception, struct pt_regs *regs) |
710 | { |
711 | if (exception == 3 && kgdb_isremovedbreak(addr: regs->ip - 1)) { |
712 | regs->ip -= 1; |
713 | return 1; |
714 | } |
715 | return 0; |
716 | } |
717 | |
718 | unsigned long kgdb_arch_pc(int exception, struct pt_regs *regs) |
719 | { |
720 | if (exception == 3) |
721 | return instruction_pointer(regs) - 1; |
722 | return instruction_pointer(regs); |
723 | } |
724 | |
725 | void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long ip) |
726 | { |
727 | regs->ip = ip; |
728 | } |
729 | |
730 | int kgdb_arch_set_breakpoint(struct kgdb_bkpt *bpt) |
731 | { |
732 | int err; |
733 | |
734 | bpt->type = BP_BREAKPOINT; |
735 | err = copy_from_kernel_nofault(dst: bpt->saved_instr, src: (char *)bpt->bpt_addr, |
736 | BREAK_INSTR_SIZE); |
737 | if (err) |
738 | return err; |
739 | err = copy_to_kernel_nofault(dst: (char *)bpt->bpt_addr, |
740 | src: arch_kgdb_ops.gdb_bpt_instr, BREAK_INSTR_SIZE); |
741 | if (!err) |
742 | return err; |
743 | /* |
744 | * It is safe to call text_poke_kgdb() because normal kernel execution |
745 | * is stopped on all cores, so long as the text_mutex is not locked. |
746 | */ |
747 | if (mutex_is_locked(lock: &text_mutex)) |
748 | return -EBUSY; |
749 | text_poke_kgdb(addr: (void *)bpt->bpt_addr, opcode: arch_kgdb_ops.gdb_bpt_instr, |
750 | BREAK_INSTR_SIZE); |
751 | bpt->type = BP_POKE_BREAKPOINT; |
752 | |
753 | return 0; |
754 | } |
755 | |
756 | int kgdb_arch_remove_breakpoint(struct kgdb_bkpt *bpt) |
757 | { |
758 | if (bpt->type != BP_POKE_BREAKPOINT) |
759 | goto knl_write; |
760 | /* |
761 | * It is safe to call text_poke_kgdb() because normal kernel execution |
762 | * is stopped on all cores, so long as the text_mutex is not locked. |
763 | */ |
764 | if (mutex_is_locked(lock: &text_mutex)) |
765 | goto knl_write; |
766 | text_poke_kgdb(addr: (void *)bpt->bpt_addr, opcode: bpt->saved_instr, |
767 | BREAK_INSTR_SIZE); |
768 | return 0; |
769 | |
770 | knl_write: |
771 | return copy_to_kernel_nofault(dst: (char *)bpt->bpt_addr, |
772 | src: (char *)bpt->saved_instr, BREAK_INSTR_SIZE); |
773 | } |
774 | |
775 | const struct kgdb_arch arch_kgdb_ops = { |
776 | /* Breakpoint instruction: */ |
777 | .gdb_bpt_instr = { 0xcc }, |
778 | .flags = KGDB_HW_BREAKPOINT, |
779 | .set_hw_breakpoint = kgdb_set_hw_break, |
780 | .remove_hw_breakpoint = kgdb_remove_hw_break, |
781 | .disable_hw_break = kgdb_disable_hw_debug, |
782 | .remove_all_hw_break = kgdb_remove_all_hw_break, |
783 | .correct_hw_break = kgdb_correct_hw_break, |
784 | }; |
785 | |