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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> |
82da3ff8 IM |
45 | |
46 | #include <asm/apicdef.h> | |
47 | #include <asm/system.h> | |
48 | ||
49 | #ifdef CONFIG_X86_32 | |
50 | # include <mach_ipi.h> | |
51 | #else | |
52 | # include <asm/mach_apic.h> | |
53 | #endif | |
54 | ||
55 | /* | |
56 | * Put the error code here just in case the user cares: | |
57 | */ | |
58 | static int gdb_x86errcode; | |
59 | ||
60 | /* | |
61 | * Likewise, the vector number here (since GDB only gets the signal | |
62 | * number through the usual means, and that's not very specific): | |
63 | */ | |
64 | static int gdb_x86vector = -1; | |
65 | ||
66 | /** | |
67 | * pt_regs_to_gdb_regs - Convert ptrace regs to GDB regs | |
68 | * @gdb_regs: A pointer to hold the registers in the order GDB wants. | |
69 | * @regs: The &struct pt_regs of the current process. | |
70 | * | |
71 | * Convert the pt_regs in @regs into the format for registers that | |
72 | * GDB expects, stored in @gdb_regs. | |
73 | */ | |
74 | void pt_regs_to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *regs) | |
75 | { | |
76 | gdb_regs[GDB_AX] = regs->ax; | |
77 | gdb_regs[GDB_BX] = regs->bx; | |
78 | gdb_regs[GDB_CX] = regs->cx; | |
79 | gdb_regs[GDB_DX] = regs->dx; | |
80 | gdb_regs[GDB_SI] = regs->si; | |
81 | gdb_regs[GDB_DI] = regs->di; | |
82 | gdb_regs[GDB_BP] = regs->bp; | |
83 | gdb_regs[GDB_PS] = regs->flags; | |
84 | gdb_regs[GDB_PC] = regs->ip; | |
85 | #ifdef CONFIG_X86_32 | |
86 | gdb_regs[GDB_DS] = regs->ds; | |
87 | gdb_regs[GDB_ES] = regs->es; | |
88 | gdb_regs[GDB_CS] = regs->cs; | |
89 | gdb_regs[GDB_SS] = __KERNEL_DS; | |
90 | gdb_regs[GDB_FS] = 0xFFFF; | |
91 | gdb_regs[GDB_GS] = 0xFFFF; | |
92 | #else | |
93 | gdb_regs[GDB_R8] = regs->r8; | |
94 | gdb_regs[GDB_R9] = regs->r9; | |
95 | gdb_regs[GDB_R10] = regs->r10; | |
96 | gdb_regs[GDB_R11] = regs->r11; | |
97 | gdb_regs[GDB_R12] = regs->r12; | |
98 | gdb_regs[GDB_R13] = regs->r13; | |
99 | gdb_regs[GDB_R14] = regs->r14; | |
100 | gdb_regs[GDB_R15] = regs->r15; | |
101 | #endif | |
102 | gdb_regs[GDB_SP] = regs->sp; | |
103 | } | |
104 | ||
105 | /** | |
106 | * sleeping_thread_to_gdb_regs - Convert ptrace regs to GDB regs | |
107 | * @gdb_regs: A pointer to hold the registers in the order GDB wants. | |
108 | * @p: The &struct task_struct of the desired process. | |
109 | * | |
110 | * Convert the register values of the sleeping process in @p to | |
111 | * the format that GDB expects. | |
112 | * This function is called when kgdb does not have access to the | |
113 | * &struct pt_regs and therefore it should fill the gdb registers | |
114 | * @gdb_regs with what has been saved in &struct thread_struct | |
115 | * thread field during switch_to. | |
116 | */ | |
117 | void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p) | |
118 | { | |
119 | gdb_regs[GDB_AX] = 0; | |
120 | gdb_regs[GDB_BX] = 0; | |
121 | gdb_regs[GDB_CX] = 0; | |
122 | gdb_regs[GDB_DX] = 0; | |
123 | gdb_regs[GDB_SI] = 0; | |
124 | gdb_regs[GDB_DI] = 0; | |
125 | gdb_regs[GDB_BP] = *(unsigned long *)p->thread.sp; | |
126 | #ifdef CONFIG_X86_32 | |
127 | gdb_regs[GDB_DS] = __KERNEL_DS; | |
128 | gdb_regs[GDB_ES] = __KERNEL_DS; | |
129 | gdb_regs[GDB_PS] = 0; | |
130 | gdb_regs[GDB_CS] = __KERNEL_CS; | |
131 | gdb_regs[GDB_PC] = p->thread.ip; | |
132 | gdb_regs[GDB_SS] = __KERNEL_DS; | |
133 | gdb_regs[GDB_FS] = 0xFFFF; | |
134 | gdb_regs[GDB_GS] = 0xFFFF; | |
135 | #else | |
136 | gdb_regs[GDB_PS] = *(unsigned long *)(p->thread.sp + 8); | |
137 | gdb_regs[GDB_PC] = 0; | |
138 | gdb_regs[GDB_R8] = 0; | |
139 | gdb_regs[GDB_R9] = 0; | |
140 | gdb_regs[GDB_R10] = 0; | |
141 | gdb_regs[GDB_R11] = 0; | |
142 | gdb_regs[GDB_R12] = 0; | |
143 | gdb_regs[GDB_R13] = 0; | |
144 | gdb_regs[GDB_R14] = 0; | |
145 | gdb_regs[GDB_R15] = 0; | |
146 | #endif | |
147 | gdb_regs[GDB_SP] = p->thread.sp; | |
148 | } | |
149 | ||
150 | /** | |
151 | * gdb_regs_to_pt_regs - Convert GDB regs to ptrace regs. | |
152 | * @gdb_regs: A pointer to hold the registers we've received from GDB. | |
153 | * @regs: A pointer to a &struct pt_regs to hold these values in. | |
154 | * | |
155 | * Convert the GDB regs in @gdb_regs into the pt_regs, and store them | |
156 | * in @regs. | |
157 | */ | |
158 | void gdb_regs_to_pt_regs(unsigned long *gdb_regs, struct pt_regs *regs) | |
159 | { | |
160 | regs->ax = gdb_regs[GDB_AX]; | |
161 | regs->bx = gdb_regs[GDB_BX]; | |
162 | regs->cx = gdb_regs[GDB_CX]; | |
163 | regs->dx = gdb_regs[GDB_DX]; | |
164 | regs->si = gdb_regs[GDB_SI]; | |
165 | regs->di = gdb_regs[GDB_DI]; | |
166 | regs->bp = gdb_regs[GDB_BP]; | |
167 | regs->flags = gdb_regs[GDB_PS]; | |
168 | regs->ip = gdb_regs[GDB_PC]; | |
169 | #ifdef CONFIG_X86_32 | |
170 | regs->ds = gdb_regs[GDB_DS]; | |
171 | regs->es = gdb_regs[GDB_ES]; | |
172 | regs->cs = gdb_regs[GDB_CS]; | |
173 | #else | |
174 | regs->r8 = gdb_regs[GDB_R8]; | |
175 | regs->r9 = gdb_regs[GDB_R9]; | |
176 | regs->r10 = gdb_regs[GDB_R10]; | |
177 | regs->r11 = gdb_regs[GDB_R11]; | |
178 | regs->r12 = gdb_regs[GDB_R12]; | |
179 | regs->r13 = gdb_regs[GDB_R13]; | |
180 | regs->r14 = gdb_regs[GDB_R14]; | |
181 | regs->r15 = gdb_regs[GDB_R15]; | |
182 | #endif | |
183 | } | |
184 | ||
185 | /** | |
186 | * kgdb_post_primary_code - Save error vector/code numbers. | |
187 | * @regs: Original pt_regs. | |
188 | * @e_vector: Original error vector. | |
189 | * @err_code: Original error code. | |
190 | * | |
191 | * This is needed on architectures which support SMP and KGDB. | |
192 | * This function is called after all the slave cpus have been put | |
193 | * to a know spin state and the primary CPU has control over KGDB. | |
194 | */ | |
195 | void kgdb_post_primary_code(struct pt_regs *regs, int e_vector, int err_code) | |
196 | { | |
197 | /* primary processor is completely in the debugger */ | |
198 | gdb_x86vector = e_vector; | |
199 | gdb_x86errcode = err_code; | |
200 | } | |
201 | ||
202 | #ifdef CONFIG_SMP | |
203 | /** | |
204 | * kgdb_roundup_cpus - Get other CPUs into a holding pattern | |
205 | * @flags: Current IRQ state | |
206 | * | |
207 | * On SMP systems, we need to get the attention of the other CPUs | |
208 | * and get them be in a known state. This should do what is needed | |
209 | * to get the other CPUs to call kgdb_wait(). Note that on some arches, | |
210 | * the NMI approach is not used for rounding up all the CPUs. For example, | |
211 | * in case of MIPS, smp_call_function() is used to roundup CPUs. In | |
212 | * this case, we have to make sure that interrupts are enabled before | |
213 | * calling smp_call_function(). The argument to this function is | |
214 | * the flags that will be used when restoring the interrupts. There is | |
215 | * local_irq_save() call before kgdb_roundup_cpus(). | |
216 | * | |
217 | * On non-SMP systems, this is not called. | |
218 | */ | |
219 | void kgdb_roundup_cpus(unsigned long flags) | |
220 | { | |
221 | send_IPI_allbutself(APIC_DM_NMI); | |
222 | } | |
223 | #endif | |
224 | ||
225 | /** | |
226 | * kgdb_arch_handle_exception - Handle architecture specific GDB packets. | |
227 | * @vector: The error vector of the exception that happened. | |
228 | * @signo: The signal number of the exception that happened. | |
229 | * @err_code: The error code of the exception that happened. | |
230 | * @remcom_in_buffer: The buffer of the packet we have read. | |
231 | * @remcom_out_buffer: The buffer of %BUFMAX bytes to write a packet into. | |
232 | * @regs: The &struct pt_regs of the current process. | |
233 | * | |
234 | * This function MUST handle the 'c' and 's' command packets, | |
235 | * as well packets to set / remove a hardware breakpoint, if used. | |
236 | * If there are additional packets which the hardware needs to handle, | |
237 | * they are handled here. The code should return -1 if it wants to | |
238 | * process more packets, and a %0 or %1 if it wants to exit from the | |
239 | * kgdb callback. | |
240 | */ | |
241 | int kgdb_arch_handle_exception(int e_vector, int signo, int err_code, | |
242 | char *remcomInBuffer, char *remcomOutBuffer, | |
243 | struct pt_regs *linux_regs) | |
244 | { | |
245 | unsigned long addr; | |
246 | char *ptr; | |
247 | int newPC; | |
248 | ||
249 | switch (remcomInBuffer[0]) { | |
250 | case 'c': | |
251 | case 's': | |
252 | /* try to read optional parameter, pc unchanged if no parm */ | |
253 | ptr = &remcomInBuffer[1]; | |
254 | if (kgdb_hex2long(&ptr, &addr)) | |
255 | linux_regs->ip = addr; | |
256 | newPC = linux_regs->ip; | |
257 | ||
258 | /* clear the trace bit */ | |
259 | linux_regs->flags &= ~TF_MASK; | |
260 | atomic_set(&kgdb_cpu_doing_single_step, -1); | |
261 | ||
262 | /* set the trace bit if we're stepping */ | |
263 | if (remcomInBuffer[0] == 's') { | |
264 | linux_regs->flags |= TF_MASK; | |
265 | kgdb_single_step = 1; | |
266 | if (kgdb_contthread) { | |
267 | atomic_set(&kgdb_cpu_doing_single_step, | |
268 | raw_smp_processor_id()); | |
269 | } | |
270 | } | |
271 | ||
272 | return 0; | |
273 | } | |
274 | ||
275 | /* this means that we do not want to exit from the handler: */ | |
276 | return -1; | |
277 | } | |
278 | ||
279 | static inline int | |
280 | single_step_cont(struct pt_regs *regs, struct die_args *args) | |
281 | { | |
282 | /* | |
283 | * Single step exception from kernel space to user space so | |
284 | * eat the exception and continue the process: | |
285 | */ | |
286 | printk(KERN_ERR "KGDB: trap/step from kernel to user space, " | |
287 | "resuming...\n"); | |
288 | kgdb_arch_handle_exception(args->trapnr, args->signr, | |
289 | args->err, "c", "", regs); | |
290 | ||
291 | return NOTIFY_STOP; | |
292 | } | |
293 | ||
d3597524 JW |
294 | static int was_in_debug_nmi[NR_CPUS]; |
295 | ||
82da3ff8 IM |
296 | static int __kgdb_notify(struct die_args *args, unsigned long cmd) |
297 | { | |
298 | struct pt_regs *regs = args->regs; | |
299 | ||
300 | switch (cmd) { | |
301 | case DIE_NMI: | |
302 | if (atomic_read(&kgdb_active) != -1) { | |
303 | /* KGDB CPU roundup */ | |
304 | kgdb_nmicallback(raw_smp_processor_id(), regs); | |
d3597524 JW |
305 | was_in_debug_nmi[raw_smp_processor_id()] = 1; |
306 | touch_nmi_watchdog(); | |
82da3ff8 IM |
307 | return NOTIFY_STOP; |
308 | } | |
309 | return NOTIFY_DONE; | |
310 | ||
311 | case DIE_NMI_IPI: | |
312 | if (atomic_read(&kgdb_active) != -1) { | |
d3597524 JW |
313 | /* KGDB CPU roundup */ |
314 | kgdb_nmicallback(raw_smp_processor_id(), regs); | |
315 | was_in_debug_nmi[raw_smp_processor_id()] = 1; | |
316 | touch_nmi_watchdog(); | |
317 | } | |
318 | return NOTIFY_DONE; | |
319 | ||
320 | case DIE_NMIUNKNOWN: | |
321 | if (was_in_debug_nmi[raw_smp_processor_id()]) { | |
322 | was_in_debug_nmi[raw_smp_processor_id()] = 0; | |
82da3ff8 IM |
323 | return NOTIFY_STOP; |
324 | } | |
325 | return NOTIFY_DONE; | |
326 | ||
327 | case DIE_NMIWATCHDOG: | |
328 | if (atomic_read(&kgdb_active) != -1) { | |
329 | /* KGDB CPU roundup: */ | |
330 | kgdb_nmicallback(raw_smp_processor_id(), regs); | |
331 | return NOTIFY_STOP; | |
332 | } | |
333 | /* Enter debugger: */ | |
334 | break; | |
335 | ||
336 | case DIE_DEBUG: | |
337 | if (atomic_read(&kgdb_cpu_doing_single_step) == | |
338 | raw_smp_processor_id() && | |
339 | user_mode(regs)) | |
340 | return single_step_cont(regs, args); | |
341 | /* fall through */ | |
342 | default: | |
343 | if (user_mode(regs)) | |
344 | return NOTIFY_DONE; | |
345 | } | |
346 | ||
347 | if (kgdb_handle_exception(args->trapnr, args->signr, args->err, regs)) | |
348 | return NOTIFY_DONE; | |
349 | ||
350 | return NOTIFY_STOP; | |
351 | } | |
352 | ||
353 | static int | |
354 | kgdb_notify(struct notifier_block *self, unsigned long cmd, void *ptr) | |
355 | { | |
356 | unsigned long flags; | |
357 | int ret; | |
358 | ||
359 | local_irq_save(flags); | |
360 | ret = __kgdb_notify(ptr, cmd); | |
361 | local_irq_restore(flags); | |
362 | ||
363 | return ret; | |
364 | } | |
365 | ||
366 | static struct notifier_block kgdb_notifier = { | |
367 | .notifier_call = kgdb_notify, | |
368 | ||
369 | /* | |
370 | * Lowest-prio notifier priority, we want to be notified last: | |
371 | */ | |
372 | .priority = -INT_MAX, | |
373 | }; | |
374 | ||
375 | /** | |
376 | * kgdb_arch_init - Perform any architecture specific initalization. | |
377 | * | |
378 | * This function will handle the initalization of any architecture | |
379 | * specific callbacks. | |
380 | */ | |
381 | int kgdb_arch_init(void) | |
382 | { | |
383 | return register_die_notifier(&kgdb_notifier); | |
384 | } | |
385 | ||
386 | /** | |
387 | * kgdb_arch_exit - Perform any architecture specific uninitalization. | |
388 | * | |
389 | * This function will handle the uninitalization of any architecture | |
390 | * specific callbacks, for dynamic registration and unregistration. | |
391 | */ | |
392 | void kgdb_arch_exit(void) | |
393 | { | |
394 | unregister_die_notifier(&kgdb_notifier); | |
395 | } | |
396 | ||
397 | /** | |
398 | * | |
399 | * kgdb_skipexception - Bail out of KGDB when we've been triggered. | |
400 | * @exception: Exception vector number | |
401 | * @regs: Current &struct pt_regs. | |
402 | * | |
403 | * On some architectures we need to skip a breakpoint exception when | |
404 | * it occurs after a breakpoint has been removed. | |
405 | * | |
406 | * Skip an int3 exception when it occurs after a breakpoint has been | |
407 | * removed. Backtrack eip by 1 since the int3 would have caused it to | |
408 | * increment by 1. | |
409 | */ | |
410 | int kgdb_skipexception(int exception, struct pt_regs *regs) | |
411 | { | |
412 | if (exception == 3 && kgdb_isremovedbreak(regs->ip - 1)) { | |
413 | regs->ip -= 1; | |
414 | return 1; | |
415 | } | |
416 | return 0; | |
417 | } | |
418 | ||
419 | unsigned long kgdb_arch_pc(int exception, struct pt_regs *regs) | |
420 | { | |
421 | if (exception == 3) | |
422 | return instruction_pointer(regs) - 1; | |
423 | return instruction_pointer(regs); | |
424 | } | |
425 | ||
426 | struct kgdb_arch arch_kgdb_ops = { | |
427 | /* Breakpoint instruction: */ | |
428 | .gdb_bpt_instr = { 0xcc }, | |
429 | }; |