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 <linux/uaccess.h>
36 #include <asm/irq_regs.h>
37
38 static struct hard_trap_info {
39 unsigned char tt; /* Trap type code for MIPS R3xxx and R4xxx */
40 unsigned char signo; /* Signal that we map this trap into */
41 } hard_trap_info[] = {
42 { 6, SIGBUS }, /* instruction bus error */
43 { 7, SIGBUS }, /* data bus error */
44 { 9, SIGTRAP }, /* break */
45 /* { 11, SIGILL }, */ /* CPU unusable */
46 { 12, SIGFPE }, /* overflow */
47 { 13, SIGTRAP }, /* trap */
48 { 14, SIGSEGV }, /* virtual instruction cache coherency */
49 { 15, SIGFPE }, /* floating point exception */
50 { 23, SIGSEGV }, /* watch */
51 { 31, SIGSEGV }, /* virtual data cache coherency */
52 { 0, 0} /* Must be last */
53 };
54
55 struct dbg_reg_def_t dbg_reg_def[DBG_MAX_REG_NUM] =
56 {
57 { "zero", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[0]) },
58 { "at", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[1]) },
59 { "v0", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[2]) },
60 { "v1", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[3]) },
61 { "a0", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[4]) },
62 { "a1", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[5]) },
63 { "a2", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[6]) },
64 { "a3", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[7]) },
65 { "t0", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[8]) },
66 { "t1", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[9]) },
67 { "t2", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[10]) },
68 { "t3", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[11]) },
69 { "t4", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[12]) },
70 { "t5", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[13]) },
71 { "t6", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[14]) },
72 { "t7", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[15]) },
73 { "s0", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[16]) },
74 { "s1", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[17]) },
75 { "s2", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[18]) },
76 { "s3", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[19]) },
77 { "s4", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[20]) },
78 { "s5", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[21]) },
79 { "s6", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[22]) },
80 { "s7", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[23]) },
81 { "t8", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[24]) },
82 { "t9", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[25]) },
83 { "k0", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[26]) },
84 { "k1", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[27]) },
85 { "gp", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[28]) },
86 { "sp", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[29]) },
87 { "s8", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[30]) },
88 { "ra", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[31]) },
89 { "sr", GDB_SIZEOF_REG, offsetof(struct pt_regs, cp0_status) },
90 { "lo", GDB_SIZEOF_REG, offsetof(struct pt_regs, lo) },
91 { "hi", GDB_SIZEOF_REG, offsetof(struct pt_regs, hi) },
92 { "bad", GDB_SIZEOF_REG, offsetof(struct pt_regs, cp0_badvaddr) },
93 { "cause", GDB_SIZEOF_REG, offsetof(struct pt_regs, cp0_cause) },
94 { "pc", GDB_SIZEOF_REG, offsetof(struct pt_regs, cp0_epc) },
95 { "f0", GDB_SIZEOF_REG, 0 },
96 { "f1", GDB_SIZEOF_REG, 1 },
97 { "f2", GDB_SIZEOF_REG, 2 },
98 { "f3", GDB_SIZEOF_REG, 3 },
99 { "f4", GDB_SIZEOF_REG, 4 },
100 { "f5", GDB_SIZEOF_REG, 5 },
101 { "f6", GDB_SIZEOF_REG, 6 },
102 { "f7", GDB_SIZEOF_REG, 7 },
103 { "f8", GDB_SIZEOF_REG, 8 },
104 { "f9", GDB_SIZEOF_REG, 9 },
105 { "f10", GDB_SIZEOF_REG, 10 },
106 { "f11", GDB_SIZEOF_REG, 11 },
107 { "f12", GDB_SIZEOF_REG, 12 },
108 { "f13", GDB_SIZEOF_REG, 13 },
109 { "f14", GDB_SIZEOF_REG, 14 },
110 { "f15", GDB_SIZEOF_REG, 15 },
111 { "f16", GDB_SIZEOF_REG, 16 },
112 { "f17", GDB_SIZEOF_REG, 17 },
113 { "f18", GDB_SIZEOF_REG, 18 },
114 { "f19", GDB_SIZEOF_REG, 19 },
115 { "f20", GDB_SIZEOF_REG, 20 },
116 { "f21", GDB_SIZEOF_REG, 21 },
117 { "f22", GDB_SIZEOF_REG, 22 },
118 { "f23", GDB_SIZEOF_REG, 23 },
119 { "f24", GDB_SIZEOF_REG, 24 },
120 { "f25", GDB_SIZEOF_REG, 25 },
121 { "f26", GDB_SIZEOF_REG, 26 },
122 { "f27", GDB_SIZEOF_REG, 27 },
123 { "f28", GDB_SIZEOF_REG, 28 },
124 { "f29", GDB_SIZEOF_REG, 29 },
125 { "f30", GDB_SIZEOF_REG, 30 },
126 { "f31", GDB_SIZEOF_REG, 31 },
127 { "fsr", GDB_SIZEOF_REG, 0 },
128 { "fir", GDB_SIZEOF_REG, 0 },
129 };
130
131 int dbg_set_reg(int regno, void *mem, struct pt_regs *regs)
132 {
133 int fp_reg;
134
135 if (regno < 0 || regno >= DBG_MAX_REG_NUM)
136 return -EINVAL;
137
138 if (dbg_reg_def[regno].offset != -1 && regno < 38) {
139 memcpy((void *)regs + dbg_reg_def[regno].offset, mem,
140 dbg_reg_def[regno].size);
141 } else if (current && dbg_reg_def[regno].offset != -1 && regno < 72) {
142 /* FP registers 38 -> 69 */
143 if (!(regs->cp0_status & ST0_CU1))
144 return 0;
145 if (regno == 70) {
146 /* Process the fcr31/fsr (register 70) */
147 memcpy((void *)¤t->thread.fpu.fcr31, mem,
148 dbg_reg_def[regno].size);
149 goto out_save;
150 } else if (regno == 71) {
151 /* Ignore the fir (register 71) */
152 goto out_save;
153 }
154 fp_reg = dbg_reg_def[regno].offset;
155 memcpy((void *)¤t->thread.fpu.fpr[fp_reg], mem,
156 dbg_reg_def[regno].size);
157 out_save:
158 restore_fp(current);
159 }
160
161 return 0;
162 }
163
164 char *dbg_get_reg(int regno, void *mem, struct pt_regs *regs)
165 {
166 int fp_reg;
167
168 if (regno >= DBG_MAX_REG_NUM || regno < 0)
169 return NULL;
170
171 if (dbg_reg_def[regno].offset != -1 && regno < 38) {
172 /* First 38 registers */
173 memcpy(mem, (void *)regs + dbg_reg_def[regno].offset,
174 dbg_reg_def[regno].size);
175 } else if (current && dbg_reg_def[regno].offset != -1 && regno < 72) {
176 /* FP registers 38 -> 69 */
177 if (!(regs->cp0_status & ST0_CU1))
178 goto out;
179 save_fp(current);
180 if (regno == 70) {
181 /* Process the fcr31/fsr (register 70) */
182 memcpy(mem, (void *)¤t->thread.fpu.fcr31,
183 dbg_reg_def[regno].size);
184 goto out;
185 } else if (regno == 71) {
186 /* Ignore the fir (register 71) */
187 memset(mem, 0, dbg_reg_def[regno].size);
188 goto out;
189 }
190 fp_reg = dbg_reg_def[regno].offset;
191 memcpy(mem, (void *)¤t->thread.fpu.fpr[fp_reg],
192 dbg_reg_def[regno].size);
193 }
194
195 out:
196 return dbg_reg_def[regno].name;
197
198 }
199
200 void arch_kgdb_breakpoint(void)
201 {
202 __asm__ __volatile__(
203 ".globl breakinst\n\t"
204 ".set\tnoreorder\n\t"
205 "nop\n"
206 "breakinst:\tbreak\n\t"
207 "nop\n\t"
208 ".set\treorder");
209 }
210
211 void kgdb_call_nmi_hook(void *ignored)
212 {
213 mm_segment_t old_fs;
214
215 old_fs = get_fs();
216 set_fs(KERNEL_DS);
217
218 kgdb_nmicallback(raw_smp_processor_id(), get_irq_regs());
219
220 set_fs(old_fs);
221 }
222
223 static int compute_signal(int tt)
224 {
225 struct hard_trap_info *ht;
226
227 for (ht = hard_trap_info; ht->tt && ht->signo; ht++)
228 if (ht->tt == tt)
229 return ht->signo;
230
231 return SIGHUP; /* default for things we don't know about */
232 }
233
234 /*
235 * Similar to regs_to_gdb_regs() except that process is sleeping and so
236 * we may not be able to get all the info.
237 */
238 void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p)
239 {
240 int reg;
241 #if (KGDB_GDB_REG_SIZE == 32)
242 u32 *ptr = (u32 *)gdb_regs;
243 #else
244 u64 *ptr = (u64 *)gdb_regs;
245 #endif
246
247 for (reg = 0; reg < 16; reg++)
248 *(ptr++) = 0;
249
250 /* S0 - S7 */
251 *(ptr++) = p->thread.reg16;
252 *(ptr++) = p->thread.reg17;
253 *(ptr++) = p->thread.reg18;
254 *(ptr++) = p->thread.reg19;
255 *(ptr++) = p->thread.reg20;
256 *(ptr++) = p->thread.reg21;
257 *(ptr++) = p->thread.reg22;
258 *(ptr++) = p->thread.reg23;
259
260 for (reg = 24; reg < 28; reg++)
261 *(ptr++) = 0;
262
263 /* GP, SP, FP, RA */
264 *(ptr++) = (long)p;
265 *(ptr++) = p->thread.reg29;
266 *(ptr++) = p->thread.reg30;
267 *(ptr++) = p->thread.reg31;
268
269 *(ptr++) = p->thread.cp0_status;
270
271 /* lo, hi */
272 *(ptr++) = 0;
273 *(ptr++) = 0;
274
275 /*
276 * BadVAddr, Cause
277 * Ideally these would come from the last exception frame up the stack
278 * but that requires unwinding, otherwise we can't know much for sure.
279 */
280 *(ptr++) = 0;
281 *(ptr++) = 0;
282
283 /*
284 * PC
285 * use return address (RA), i.e. the moment after return from resume()
286 */
287 *(ptr++) = p->thread.reg31;
288 }
289
290 void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long pc)
291 {
292 regs->cp0_epc = pc;
293 }
294
295 /*
296 * Calls linux_debug_hook before the kernel dies. If KGDB is enabled,
297 * then try to fall into the debugger
298 */
299 static int kgdb_mips_notify(struct notifier_block *self, unsigned long cmd,
300 void *ptr)
301 {
302 struct die_args *args = (struct die_args *)ptr;
303 struct pt_regs *regs = args->regs;
304 int trap = (regs->cp0_cause & 0x7c) >> 2;
305 mm_segment_t old_fs;
306
307 #ifdef CONFIG_KPROBES
308 /*
309 * Return immediately if the kprobes fault notifier has set
310 * DIE_PAGE_FAULT.
311 */
312 if (cmd == DIE_PAGE_FAULT)
313 return NOTIFY_DONE;
314 #endif /* CONFIG_KPROBES */
315
316 /* Userspace events, ignore. */
317 if (user_mode(regs))
318 return NOTIFY_DONE;
319
320 /* Kernel mode. Set correct address limit */
321 old_fs = get_fs();
322 set_fs(KERNEL_DS);
323
324 if (atomic_read(&kgdb_active) != -1)
325 kgdb_nmicallback(smp_processor_id(), regs);
326
327 if (kgdb_handle_exception(trap, compute_signal(trap), cmd, regs)) {
328 set_fs(old_fs);
329 return NOTIFY_DONE;
330 }
331
332 if (atomic_read(&kgdb_setting_breakpoint))
333 if ((trap == 9) && (regs->cp0_epc == (unsigned long)breakinst))
334 regs->cp0_epc += 4;
335
336 /* In SMP mode, __flush_cache_all does IPI */
337 local_irq_enable();
338 __flush_cache_all();
339
340 set_fs(old_fs);
341 return NOTIFY_STOP;
342 }
343
344 #ifdef CONFIG_KGDB_LOW_LEVEL_TRAP
345 int kgdb_ll_trap(int cmd, const char *str,
346 struct pt_regs *regs, long err, int trap, int sig)
347 {
348 struct die_args args = {
349 .regs = regs,
350 .str = str,
351 .err = err,
352 .trapnr = trap,
353 .signr = sig,
354
355 };
356
357 if (!kgdb_io_module_registered)
358 return NOTIFY_DONE;
359
360 return kgdb_mips_notify(NULL, cmd, &args);
361 }
362 #endif /* CONFIG_KGDB_LOW_LEVEL_TRAP */
363
364 static struct notifier_block kgdb_notifier = {
365 .notifier_call = kgdb_mips_notify,
366 };
367
368 /*
369 * Handle the 'c' command
370 */
371 int kgdb_arch_handle_exception(int vector, int signo, int err_code,
372 char *remcom_in_buffer, char *remcom_out_buffer,
373 struct pt_regs *regs)
374 {
375 char *ptr;
376 unsigned long address;
377
378 switch (remcom_in_buffer[0]) {
379 case 'c':
380 /* handle the optional parameter */
381 ptr = &remcom_in_buffer[1];
382 if (kgdb_hex2long(&ptr, &address))
383 regs->cp0_epc = address;
384
385 return 0;
386 }
387
388 return -1;
389 }
390
391 const struct kgdb_arch arch_kgdb_ops = {
392 #ifdef CONFIG_CPU_BIG_ENDIAN
393 .gdb_bpt_instr = { spec_op << 2, 0x00, 0x00, break_op },
394 #else
395 .gdb_bpt_instr = { break_op, 0x00, 0x00, spec_op << 2 },
396 #endif
397 };
398
399 int kgdb_arch_init(void)
400 {
401 register_die_notifier(&kgdb_notifier);
402
403 return 0;
404 }
405
406 /*
407 * kgdb_arch_exit - Perform any architecture specific uninitalization.
408 *
409 * This function will handle the uninitalization of any architecture
410 * specific callbacks, for dynamic registration and unregistration.
411 */
412 void kgdb_arch_exit(void)
413 {
414 unregister_die_notifier(&kgdb_notifier);
415 }
416
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