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 #include <asm/irq_regs.h>
36
37 static struct hard_trap_info {
38 unsigned char tt; /* Trap type code for MIPS R3xxx and R4xxx */
39 unsigned char signo; /* Signal that we map this trap into */
40 } hard_trap_info[] = {
41 { 6, SIGBUS }, /* instruction bus error */
42 { 7, SIGBUS }, /* data bus error */
43 { 9, SIGTRAP }, /* break */
44 /* { 11, SIGILL }, */ /* CPU unusable */
45 { 12, SIGFPE }, /* overflow */
46 { 13, SIGTRAP }, /* trap */
47 { 14, SIGSEGV }, /* virtual instruction cache coherency */
48 { 15, SIGFPE }, /* floating point exception */
49 { 23, SIGSEGV }, /* watch */
50 { 31, SIGSEGV }, /* virtual data cache coherency */
51 { 0, 0} /* Must be last */
52 };
53
54 struct dbg_reg_def_t dbg_reg_def[DBG_MAX_REG_NUM] =
55 {
56 { "zero", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[0]) },
57 { "at", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[1]) },
58 { "v0", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[2]) },
59 { "v1", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[3]) },
60 { "a0", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[4]) },
61 { "a1", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[5]) },
62 { "a2", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[6]) },
63 { "a3", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[7]) },
64 { "t0", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[8]) },
65 { "t1", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[9]) },
66 { "t2", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[10]) },
67 { "t3", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[11]) },
68 { "t4", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[12]) },
69 { "t5", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[13]) },
70 { "t6", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[14]) },
71 { "t7", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[15]) },
72 { "s0", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[16]) },
73 { "s1", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[17]) },
74 { "s2", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[18]) },
75 { "s3", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[19]) },
76 { "s4", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[20]) },
77 { "s5", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[21]) },
78 { "s6", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[22]) },
79 { "s7", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[23]) },
80 { "t8", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[24]) },
81 { "t9", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[25]) },
82 { "k0", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[26]) },
83 { "k1", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[27]) },
84 { "gp", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[28]) },
85 { "sp", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[29]) },
86 { "s8", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[30]) },
87 { "ra", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[31]) },
88 { "sr", GDB_SIZEOF_REG, offsetof(struct pt_regs, cp0_status) },
89 { "lo", GDB_SIZEOF_REG, offsetof(struct pt_regs, lo) },
90 { "hi", GDB_SIZEOF_REG, offsetof(struct pt_regs, hi) },
91 { "bad", GDB_SIZEOF_REG, offsetof(struct pt_regs, cp0_badvaddr) },
92 { "cause", GDB_SIZEOF_REG, offsetof(struct pt_regs, cp0_cause) },
93 { "pc", GDB_SIZEOF_REG, offsetof(struct pt_regs, cp0_epc) },
94 { "f0", GDB_SIZEOF_REG, 0 },
95 { "f1", GDB_SIZEOF_REG, 1 },
96 { "f2", GDB_SIZEOF_REG, 2 },
97 { "f3", GDB_SIZEOF_REG, 3 },
98 { "f4", GDB_SIZEOF_REG, 4 },
99 { "f5", GDB_SIZEOF_REG, 5 },
100 { "f6", GDB_SIZEOF_REG, 6 },
101 { "f7", GDB_SIZEOF_REG, 7 },
102 { "f8", GDB_SIZEOF_REG, 8 },
103 { "f9", GDB_SIZEOF_REG, 9 },
104 { "f10", GDB_SIZEOF_REG, 10 },
105 { "f11", GDB_SIZEOF_REG, 11 },
106 { "f12", GDB_SIZEOF_REG, 12 },
107 { "f13", GDB_SIZEOF_REG, 13 },
108 { "f14", GDB_SIZEOF_REG, 14 },
109 { "f15", GDB_SIZEOF_REG, 15 },
110 { "f16", GDB_SIZEOF_REG, 16 },
111 { "f17", GDB_SIZEOF_REG, 17 },
112 { "f18", GDB_SIZEOF_REG, 18 },
113 { "f19", GDB_SIZEOF_REG, 19 },
114 { "f20", GDB_SIZEOF_REG, 20 },
115 { "f21", GDB_SIZEOF_REG, 21 },
116 { "f22", GDB_SIZEOF_REG, 22 },
117 { "f23", GDB_SIZEOF_REG, 23 },
118 { "f24", GDB_SIZEOF_REG, 24 },
119 { "f25", GDB_SIZEOF_REG, 25 },
120 { "f26", GDB_SIZEOF_REG, 26 },
121 { "f27", GDB_SIZEOF_REG, 27 },
122 { "f28", GDB_SIZEOF_REG, 28 },
123 { "f29", GDB_SIZEOF_REG, 29 },
124 { "f30", GDB_SIZEOF_REG, 30 },
125 { "f31", GDB_SIZEOF_REG, 31 },
126 { "fsr", GDB_SIZEOF_REG, 0 },
127 { "fir", GDB_SIZEOF_REG, 0 },
128 };
129
130 int dbg_set_reg(int regno, void *mem, struct pt_regs *regs)
131 {
132 int fp_reg;
133
134 if (regno < 0 || regno >= DBG_MAX_REG_NUM)
135 return -EINVAL;
136
137 if (dbg_reg_def[regno].offset != -1 && regno < 38) {
138 memcpy((void *)regs + dbg_reg_def[regno].offset, mem,
139 dbg_reg_def[regno].size);
140 } else if (current && dbg_reg_def[regno].offset != -1 && regno < 72) {
141 /* FP registers 38 -> 69 */
142 if (!(regs->cp0_status & ST0_CU1))
143 return 0;
144 if (regno == 70) {
145 /* Process the fcr31/fsr (register 70) */
146 memcpy((void *)¤t->thread.fpu.fcr31, mem,
147 dbg_reg_def[regno].size);
148 goto out_save;
149 } else if (regno == 71) {
150 /* Ignore the fir (register 71) */
151 goto out_save;
152 }
153 fp_reg = dbg_reg_def[regno].offset;
154 memcpy((void *)¤t->thread.fpu.fpr[fp_reg], mem,
155 dbg_reg_def[regno].size);
156 out_save:
157 restore_fp(current);
158 }
159
160 return 0;
161 }
162
163 char *dbg_get_reg(int regno, void *mem, struct pt_regs *regs)
164 {
165 int fp_reg;
166
167 if (regno >= DBG_MAX_REG_NUM || regno < 0)
168 return NULL;
169
170 if (dbg_reg_def[regno].offset != -1 && regno < 38) {
171 /* First 38 registers */
172 memcpy(mem, (void *)regs + dbg_reg_def[regno].offset,
173 dbg_reg_def[regno].size);
174 } else if (current && dbg_reg_def[regno].offset != -1 && regno < 72) {
175 /* FP registers 38 -> 69 */
176 if (!(regs->cp0_status & ST0_CU1))
177 goto out;
178 save_fp(current);
179 if (regno == 70) {
180 /* Process the fcr31/fsr (register 70) */
181 memcpy(mem, (void *)¤t->thread.fpu.fcr31,
182 dbg_reg_def[regno].size);
183 goto out;
184 } else if (regno == 71) {
185 /* Ignore the fir (register 71) */
186 memset(mem, 0, dbg_reg_def[regno].size);
187 goto out;
188 }
189 fp_reg = dbg_reg_def[regno].offset;
190 memcpy(mem, (void *)¤t->thread.fpu.fpr[fp_reg],
191 dbg_reg_def[regno].size);
192 }
193
194 out:
195 return dbg_reg_def[regno].name;
196
197 }
198
199 void arch_kgdb_breakpoint(void)
200 {
201 __asm__ __volatile__(
202 ".globl breakinst\n\t"
203 ".set\tnoreorder\n\t"
204 "nop\n"
205 "breakinst:\tbreak\n\t"
206 "nop\n\t"
207 ".set\treorder");
208 }
209
210 static int compute_signal(int tt)
211 {
212 struct hard_trap_info *ht;
213
214 for (ht = hard_trap_info; ht->tt && ht->signo; ht++)
215 if (ht->tt == tt)
216 return ht->signo;
217
218 return SIGHUP; /* default for things we don't know about */
219 }
220
221 /*
222 * Similar to regs_to_gdb_regs() except that process is sleeping and so
223 * we may not be able to get all the info.
224 */
225 void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p)
226 {
227 int reg;
228 #if (KGDB_GDB_REG_SIZE == 32)
229 u32 *ptr = (u32 *)gdb_regs;
230 #else
231 u64 *ptr = (u64 *)gdb_regs;
232 #endif
233
234 for (reg = 0; reg < 16; reg++)
235 *(ptr++) = 0;
236
237 /* S0 - S7 */
238 *(ptr++) = p->thread.reg16;
239 *(ptr++) = p->thread.reg17;
240 *(ptr++) = p->thread.reg18;
241 *(ptr++) = p->thread.reg19;
242 *(ptr++) = p->thread.reg20;
243 *(ptr++) = p->thread.reg21;
244 *(ptr++) = p->thread.reg22;
245 *(ptr++) = p->thread.reg23;
246
247 for (reg = 24; reg < 28; reg++)
248 *(ptr++) = 0;
249
250 /* GP, SP, FP, RA */
251 *(ptr++) = (long)p;
252 *(ptr++) = p->thread.reg29;
253 *(ptr++) = p->thread.reg30;
254 *(ptr++) = p->thread.reg31;
255
256 *(ptr++) = p->thread.cp0_status;
257
258 /* lo, hi */
259 *(ptr++) = 0;
260 *(ptr++) = 0;
261
262 /*
263 * BadVAddr, Cause
264 * Ideally these would come from the last exception frame up the stack
265 * but that requires unwinding, otherwise we can't know much for sure.
266 */
267 *(ptr++) = 0;
268 *(ptr++) = 0;
269
270 /*
271 * PC
272 * use return address (RA), i.e. the moment after return from resume()
273 */
274 *(ptr++) = p->thread.reg31;
275 }
276
277 void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long pc)
278 {
279 regs->cp0_epc = pc;
280 }
281
282 /*
283 * Calls linux_debug_hook before the kernel dies. If KGDB is enabled,
284 * then try to fall into the debugger
285 */
286 static int kgdb_mips_notify(struct notifier_block *self, unsigned long cmd,
287 void *ptr)
288 {
289 struct die_args *args = (struct die_args *)ptr;
290 struct pt_regs *regs = args->regs;
291 int trap = (regs->cp0_cause & 0x7c) >> 2;
292
293 #ifdef CONFIG_KPROBES
294 /*
295 * Return immediately if the kprobes fault notifier has set
296 * DIE_PAGE_FAULT.
297 */
298 if (cmd == DIE_PAGE_FAULT)
299 return NOTIFY_DONE;
300 #endif /* CONFIG_KPROBES */
301
302 /* Userspace events, ignore. */
303 if (user_mode(regs))
304 return NOTIFY_DONE;
305
306 if (atomic_read(&kgdb_active) != -1)
307 kgdb_nmicallback(smp_processor_id(), regs);
308
309 if (kgdb_handle_exception(trap, compute_signal(trap), cmd, regs))
310 return NOTIFY_DONE;
311
312 if (atomic_read(&kgdb_setting_breakpoint))
313 if ((trap == 9) && (regs->cp0_epc == (unsigned long)breakinst))
314 regs->cp0_epc += 4;
315
316 /* In SMP mode, __flush_cache_all does IPI */
317 local_irq_enable();
318 __flush_cache_all();
319
320 return NOTIFY_STOP;
321 }
322
323 #ifdef CONFIG_KGDB_LOW_LEVEL_TRAP
324 int kgdb_ll_trap(int cmd, const char *str,
325 struct pt_regs *regs, long err, int trap, int sig)
326 {
327 struct die_args args = {
328 .regs = regs,
329 .str = str,
330 .err = err,
331 .trapnr = trap,
332 .signr = sig,
333
334 };
335
336 if (!kgdb_io_module_registered)
337 return NOTIFY_DONE;
338
339 return kgdb_mips_notify(NULL, cmd, &args);
340 }
341 #endif /* CONFIG_KGDB_LOW_LEVEL_TRAP */
342
343 static struct notifier_block kgdb_notifier = {
344 .notifier_call = kgdb_mips_notify,
345 };
346
347 /*
348 * Handle the 'c' command
349 */
350 int kgdb_arch_handle_exception(int vector, int signo, int err_code,
351 char *remcom_in_buffer, char *remcom_out_buffer,
352 struct pt_regs *regs)
353 {
354 char *ptr;
355 unsigned long address;
356
357 switch (remcom_in_buffer[0]) {
358 case 'c':
359 /* handle the optional parameter */
360 ptr = &remcom_in_buffer[1];
361 if (kgdb_hex2long(&ptr, &address))
362 regs->cp0_epc = address;
363
364 return 0;
365 }
366
367 return -1;
368 }
369
370 const struct kgdb_arch arch_kgdb_ops = {
371 #ifdef CONFIG_CPU_BIG_ENDIAN
372 .gdb_bpt_instr = { spec_op << 2, 0x00, 0x00, break_op },
373 #else
374 .gdb_bpt_instr = { break_op, 0x00, 0x00, spec_op << 2 },
375 #endif
376 };
377
378 int kgdb_arch_init(void)
379 {
380 register_die_notifier(&kgdb_notifier);
381
382 return 0;
383 }
384
385 /*
386 * kgdb_arch_exit - Perform any architecture specific uninitalization.
387 *
388 * This function will handle the uninitalization of any architecture
389 * specific callbacks, for dynamic registration and unregistration.
390 */
391 void kgdb_arch_exit(void)
392 {
393 unregister_die_notifier(&kgdb_notifier);
394 }
395
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