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Linux 3.11-rc3
[cris-mirror.git] / arch / mips / kernel / kgdb.c
blobfcaac2f132f08e850e1a4088788e6327c2ce4f64
1 /*
2 * Originally written by Glenn Engel, Lake Stevens Instrument Division
3 *
4 * Contributed by HP Systems
5 *
6 * Modified for Linux/MIPS (and MIPS in general) by Andreas Busse
7 * Send complaints, suggestions etc. to <andy@waldorf-gmbh.de>
8 *
9 * Copyright (C) 1995 Andreas Busse
10 *
11 * Copyright (C) 2003 MontaVista Software Inc.
12 * Author: Jun Sun, jsun@mvista.com or jsun@junsun.net
13 *
14 * Copyright (C) 2004-2005 MontaVista Software Inc.
15 * Author: Manish Lachwani, mlachwani@mvista.com or manish@koffee-break.com
16 *
17 * Copyright (C) 2007-2008 Wind River Systems, Inc.
18 * Author/Maintainer: Jason Wessel, jason.wessel@windriver.com
19 *
20 * This file is licensed under the terms of the GNU General Public License
21 * version 2. This program is licensed "as is" without any warranty of any
22 * kind, whether express or implied.
23 */
24
25 #include <linux/ptrace.h> /* for linux pt_regs struct */
26 #include <linux/kgdb.h>
27 #include <linux/kdebug.h>
28 #include <linux/sched.h>
29 #include <linux/smp.h>
30 #include <asm/inst.h>
31 #include <asm/fpu.h>
32 #include <asm/cacheflush.h>
33 #include <asm/processor.h>
34 #include <asm/sigcontext.h>
35
36 static struct hard_trap_info {
37 unsigned char tt; /* Trap type code for MIPS R3xxx and R4xxx */
38 unsigned char signo; /* Signal that we map this trap into */
39 } hard_trap_info[] = {
40 { 6, SIGBUS }, /* instruction bus error */
41 { 7, SIGBUS }, /* data bus error */
42 { 9, SIGTRAP }, /* break */
43 /* { 11, SIGILL }, */ /* CPU unusable */
44 { 12, SIGFPE }, /* overflow */
45 { 13, SIGTRAP }, /* trap */
46 { 14, SIGSEGV }, /* virtual instruction cache coherency */
47 { 15, SIGFPE }, /* floating point exception */
48 { 23, SIGSEGV }, /* watch */
49 { 31, SIGSEGV }, /* virtual data cache coherency */
50 { 0, 0} /* Must be last */
51 };
52
53 struct dbg_reg_def_t dbg_reg_def[DBG_MAX_REG_NUM] =
54 {
55 { "zero", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[0]) },
56 { "at", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[1]) },
57 { "v0", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[2]) },
58 { "v1", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[3]) },
59 { "a0", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[4]) },
60 { "a1", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[5]) },
61 { "a2", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[6]) },
62 { "a3", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[7]) },
63 { "t0", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[8]) },
64 { "t1", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[9]) },
65 { "t2", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[10]) },
66 { "t3", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[11]) },
67 { "t4", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[12]) },
68 { "t5", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[13]) },
69 { "t6", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[14]) },
70 { "t7", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[15]) },
71 { "s0", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[16]) },
72 { "s1", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[17]) },
73 { "s2", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[18]) },
74 { "s3", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[19]) },
75 { "s4", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[20]) },
76 { "s5", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[21]) },
77 { "s6", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[22]) },
78 { "s7", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[23]) },
79 { "t8", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[24]) },
80 { "t9", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[25]) },
81 { "k0", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[26]) },
82 { "k1", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[27]) },
83 { "gp", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[28]) },
84 { "sp", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[29]) },
85 { "s8", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[30]) },
86 { "ra", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[31]) },
87 { "sr", GDB_SIZEOF_REG, offsetof(struct pt_regs, cp0_status) },
88 { "lo", GDB_SIZEOF_REG, offsetof(struct pt_regs, lo) },
89 { "hi", GDB_SIZEOF_REG, offsetof(struct pt_regs, hi) },
90 { "bad", GDB_SIZEOF_REG, offsetof(struct pt_regs, cp0_badvaddr) },
91 { "cause", GDB_SIZEOF_REG, offsetof(struct pt_regs, cp0_cause) },
92 { "pc", GDB_SIZEOF_REG, offsetof(struct pt_regs, cp0_epc) },
93 { "f0", GDB_SIZEOF_REG, 0 },
94 { "f1", GDB_SIZEOF_REG, 1 },
95 { "f2", GDB_SIZEOF_REG, 2 },
96 { "f3", GDB_SIZEOF_REG, 3 },
97 { "f4", GDB_SIZEOF_REG, 4 },
98 { "f5", GDB_SIZEOF_REG, 5 },
99 { "f6", GDB_SIZEOF_REG, 6 },
100 { "f7", GDB_SIZEOF_REG, 7 },
101 { "f8", GDB_SIZEOF_REG, 8 },
102 { "f9", GDB_SIZEOF_REG, 9 },
103 { "f10", GDB_SIZEOF_REG, 10 },
104 { "f11", GDB_SIZEOF_REG, 11 },
105 { "f12", GDB_SIZEOF_REG, 12 },
106 { "f13", GDB_SIZEOF_REG, 13 },
107 { "f14", GDB_SIZEOF_REG, 14 },
108 { "f15", GDB_SIZEOF_REG, 15 },
109 { "f16", GDB_SIZEOF_REG, 16 },
110 { "f17", GDB_SIZEOF_REG, 17 },
111 { "f18", GDB_SIZEOF_REG, 18 },
112 { "f19", GDB_SIZEOF_REG, 19 },
113 { "f20", GDB_SIZEOF_REG, 20 },
114 { "f21", GDB_SIZEOF_REG, 21 },
115 { "f22", GDB_SIZEOF_REG, 22 },
116 { "f23", GDB_SIZEOF_REG, 23 },
117 { "f24", GDB_SIZEOF_REG, 24 },
118 { "f25", GDB_SIZEOF_REG, 25 },
119 { "f26", GDB_SIZEOF_REG, 26 },
120 { "f27", GDB_SIZEOF_REG, 27 },
121 { "f28", GDB_SIZEOF_REG, 28 },
122 { "f29", GDB_SIZEOF_REG, 29 },
123 { "f30", GDB_SIZEOF_REG, 30 },
124 { "f31", GDB_SIZEOF_REG, 31 },
125 { "fsr", GDB_SIZEOF_REG, 0 },
126 { "fir", GDB_SIZEOF_REG, 0 },
127 };
128
129 int dbg_set_reg(int regno, void *mem, struct pt_regs *regs)
130 {
131 int fp_reg;
132
133 if (regno < 0 || regno >= DBG_MAX_REG_NUM)
134 return -EINVAL;
135
136 if (dbg_reg_def[regno].offset != -1 && regno < 38) {
137 memcpy((void *)regs + dbg_reg_def[regno].offset, mem,
138 dbg_reg_def[regno].size);
139 } else if (current && dbg_reg_def[regno].offset != -1 && regno < 72) {
140 /* FP registers 38 -> 69 */
141 if (!(regs->cp0_status & ST0_CU1))
142 return 0;
143 if (regno == 70) {
144 /* Process the fcr31/fsr (register 70) */
145 memcpy((void *)&current->thread.fpu.fcr31, mem,
146 dbg_reg_def[regno].size);
147 goto out_save;
148 } else if (regno == 71) {
149 /* Ignore the fir (register 71) */
150 goto out_save;
151 }
152 fp_reg = dbg_reg_def[regno].offset;
153 memcpy((void *)&current->thread.fpu.fpr[fp_reg], mem,
154 dbg_reg_def[regno].size);
155 out_save:
156 restore_fp(current);
157 }
158
159 return 0;
160 }
161
162 char *dbg_get_reg(int regno, void *mem, struct pt_regs *regs)
163 {
164 int fp_reg;
165
166 if (regno >= DBG_MAX_REG_NUM || regno < 0)
167 return NULL;
168
169 if (dbg_reg_def[regno].offset != -1 && regno < 38) {
170 /* First 38 registers */
171 memcpy(mem, (void *)regs + dbg_reg_def[regno].offset,
172 dbg_reg_def[regno].size);
173 } else if (current && dbg_reg_def[regno].offset != -1 && regno < 72) {
174 /* FP registers 38 -> 69 */
175 if (!(regs->cp0_status & ST0_CU1))
176 goto out;
177 save_fp(current);
178 if (regno == 70) {
179 /* Process the fcr31/fsr (register 70) */
180 memcpy(mem, (void *)&current->thread.fpu.fcr31,
181 dbg_reg_def[regno].size);
182 goto out;
183 } else if (regno == 71) {
184 /* Ignore the fir (register 71) */
185 memset(mem, 0, dbg_reg_def[regno].size);
186 goto out;
187 }
188 fp_reg = dbg_reg_def[regno].offset;
189 memcpy(mem, (void *)&current->thread.fpu.fpr[fp_reg],
190 dbg_reg_def[regno].size);
191 }
192
193 out:
194 return dbg_reg_def[regno].name;
195
196 }
197
198 void arch_kgdb_breakpoint(void)
199 {
200 __asm__ __volatile__(
201 ".globl breakinst\n\t"
202 ".set\tnoreorder\n\t"
203 "nop\n"
204 "breakinst:\tbreak\n\t"
205 "nop\n\t"
206 ".set\treorder");
207 }
208
209 static void kgdb_call_nmi_hook(void *ignored)
210 {
211 kgdb_nmicallback(raw_smp_processor_id(), NULL);
212 }
213
214 void kgdb_roundup_cpus(unsigned long flags)
215 {
216 local_irq_enable();
217 smp_call_function(kgdb_call_nmi_hook, NULL, 0);
218 local_irq_disable();
219 }
220
221 static int compute_signal(int tt)
222 {
223 struct hard_trap_info *ht;
224
225 for (ht = hard_trap_info; ht->tt && ht->signo; ht++)
226 if (ht->tt == tt)
227 return ht->signo;
228
229 return SIGHUP; /* default for things we don't know about */
230 }
231
232 /*
233 * Similar to regs_to_gdb_regs() except that process is sleeping and so
234 * we may not be able to get all the info.
235 */
236 void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p)
237 {
238 int reg;
239 struct thread_info *ti = task_thread_info(p);
240 unsigned long ksp = (unsigned long)ti + THREAD_SIZE - 32;
241 struct pt_regs *regs = (struct pt_regs *)ksp - 1;
242 #if (KGDB_GDB_REG_SIZE == 32)
243 u32 *ptr = (u32 *)gdb_regs;
244 #else
245 u64 *ptr = (u64 *)gdb_regs;
246 #endif
247
248 for (reg = 0; reg < 16; reg++)
249 *(ptr++) = regs->regs[reg];
250
251 /* S0 - S7 */
252 for (reg = 16; reg < 24; reg++)
253 *(ptr++) = regs->regs[reg];
254
255 for (reg = 24; reg < 28; reg++)
256 *(ptr++) = 0;
257
258 /* GP, SP, FP, RA */
259 for (reg = 28; reg < 32; reg++)
260 *(ptr++) = regs->regs[reg];
261
262 *(ptr++) = regs->cp0_status;
263 *(ptr++) = regs->lo;
264 *(ptr++) = regs->hi;
265 *(ptr++) = regs->cp0_badvaddr;
266 *(ptr++) = regs->cp0_cause;
267 *(ptr++) = regs->cp0_epc;
268 }
269
270 void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long pc)
271 {
272 regs->cp0_epc = pc;
273 }
274
275 /*
276 * Calls linux_debug_hook before the kernel dies. If KGDB is enabled,
277 * then try to fall into the debugger
278 */
279 static int kgdb_mips_notify(struct notifier_block *self, unsigned long cmd,
280 void *ptr)
281 {
282 struct die_args *args = (struct die_args *)ptr;
283 struct pt_regs *regs = args->regs;
284 int trap = (regs->cp0_cause & 0x7c) >> 2;
285
286 #ifdef CONFIG_KPROBES
287 /*
288 * Return immediately if the kprobes fault notifier has set
289 * DIE_PAGE_FAULT.
290 */
291 if (cmd == DIE_PAGE_FAULT)
292 return NOTIFY_DONE;
293 #endif /* CONFIG_KPROBES */
294
295 /* Userspace events, ignore. */
296 if (user_mode(regs))
297 return NOTIFY_DONE;
298
299 if (atomic_read(&kgdb_active) != -1)
300 kgdb_nmicallback(smp_processor_id(), regs);
301
302 if (kgdb_handle_exception(trap, compute_signal(trap), cmd, regs))
303 return NOTIFY_DONE;
304
305 if (atomic_read(&kgdb_setting_breakpoint))
306 if ((trap == 9) && (regs->cp0_epc == (unsigned long)breakinst))
307 regs->cp0_epc += 4;
308
309 /* In SMP mode, __flush_cache_all does IPI */
310 local_irq_enable();
311 __flush_cache_all();
312
313 return NOTIFY_STOP;
314 }
315
316 #ifdef CONFIG_KGDB_LOW_LEVEL_TRAP
317 int kgdb_ll_trap(int cmd, const char *str,
318 struct pt_regs *regs, long err, int trap, int sig)
319 {
320 struct die_args args = {
321 .regs = regs,
322 .str = str,
323 .err = err,
324 .trapnr = trap,
325 .signr = sig,
326
327 };
328
329 if (!kgdb_io_module_registered)
330 return NOTIFY_DONE;
331
332 return kgdb_mips_notify(NULL, cmd, &args);
333 }
334 #endif /* CONFIG_KGDB_LOW_LEVEL_TRAP */
335
336 static struct notifier_block kgdb_notifier = {
337 .notifier_call = kgdb_mips_notify,
338 };
339
340 /*
341 * Handle the 'c' command
342 */
343 int kgdb_arch_handle_exception(int vector, int signo, int err_code,
344 char *remcom_in_buffer, char *remcom_out_buffer,
345 struct pt_regs *regs)
346 {
347 char *ptr;
348 unsigned long address;
349
350 switch (remcom_in_buffer[0]) {
351 case 'c':
352 /* handle the optional parameter */
353 ptr = &remcom_in_buffer[1];
354 if (kgdb_hex2long(&ptr, &address))
355 regs->cp0_epc = address;
356
357 return 0;
358 }
359
360 return -1;
361 }
362
363 struct kgdb_arch arch_kgdb_ops;
364
365 /*
366 * We use kgdb_early_setup so that functions we need to call now don't
367 * cause trouble when called again later.
368 */
369 int kgdb_arch_init(void)
370 {
371 union mips_instruction insn = {
372 .r_format = {
373 .opcode = spec_op,
374 .func = break_op,
375 }
376 };
377 memcpy(arch_kgdb_ops.gdb_bpt_instr, insn.byte, BREAK_INSTR_SIZE);
378
379 register_die_notifier(&kgdb_notifier);
380
381 return 0;
382 }
383
384 /*
385 * kgdb_arch_exit - Perform any architecture specific uninitalization.
386 *
387 * This function will handle the uninitalization of any architecture
388 * specific callbacks, for dynamic registration and unregistration.
389 */
390 void kgdb_arch_exit(void)
391 {
392 unregister_die_notifier(&kgdb_notifier);
393 }
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