1 /*
2 * PowerPC backend to the KGDB stub.
3 *
4 * 1998 (c) Michael AK Tesch (tesch@cs.wisc.edu)
5 * Copyright (C) 2003 Timesys Corporation.
6 * Copyright (C) 2004-2006 MontaVista Software, Inc.
7 * PPC64 Mods (C) 2005 Frank Rowand (frowand@mvista.com)
8 * PPC32 support restored by Vitaly Wool <vwool@ru.mvista.com> and
9 * Sergei Shtylyov <sshtylyov@ru.mvista.com>
10 * Copyright (C) 2007-2008 Wind River Systems, Inc.
11 *
12 * This file is licensed under the terms of the GNU General Public License
13 * version 2. This program as licensed "as is" without any warranty of any
14 * kind, whether express or implied.
15 */
16
17 #include <linux/kernel.h>
18 #include <linux/kgdb.h>
19 #include <linux/smp.h>
20 #include <linux/signal.h>
21 #include <linux/ptrace.h>
22 #include <linux/kdebug.h>
23 #include <asm/current.h>
24 #include <asm/processor.h>
25 #include <asm/machdep.h>
26 #include <asm/debug.h>
27 #include <asm/code-patching.h>
28 #include <linux/slab.h>
29 #include <asm/inst.h>
30
31 /*
32 * This table contains the mapping between PowerPC hardware trap types, and
33 * signals, which are primarily what GDB understands. GDB and the kernel
34 * don't always agree on values, so we use constants taken from gdb-6.2.
35 */
36 static struct hard_trap_info
37 {
38 unsigned int tt; /* Trap type code for powerpc */
39 unsigned char signo; /* Signal that we map this trap into */
40 } hard_trap_info[] = {
41 { 0x0100, 0x02 /* SIGINT */ }, /* system reset */
42 { 0x0200, 0x0b /* SIGSEGV */ }, /* machine check */
43 { 0x0300, 0x0b /* SIGSEGV */ }, /* data access */
44 { 0x0400, 0x0b /* SIGSEGV */ }, /* instruction access */
45 { 0x0500, 0x02 /* SIGINT */ }, /* external interrupt */
46 { 0x0600, 0x0a /* SIGBUS */ }, /* alignment */
47 { 0x0700, 0x05 /* SIGTRAP */ }, /* program check */
48 { 0x0800, 0x08 /* SIGFPE */ }, /* fp unavailable */
49 { 0x0900, 0x0e /* SIGALRM */ }, /* decrementer */
50 { 0x0c00, 0x14 /* SIGCHLD */ }, /* system call */
51 #ifdef CONFIG_BOOKE_OR_40x
52 { 0x2002, 0x05 /* SIGTRAP */ }, /* debug */
53 #if defined(CONFIG_FSL_BOOKE)
54 { 0x2010, 0x08 /* SIGFPE */ }, /* spe unavailable */
55 { 0x2020, 0x08 /* SIGFPE */ }, /* spe unavailable */
56 { 0x2030, 0x08 /* SIGFPE */ }, /* spe fp data */
57 { 0x2040, 0x08 /* SIGFPE */ }, /* spe fp data */
58 { 0x2050, 0x08 /* SIGFPE */ }, /* spe fp round */
59 { 0x2060, 0x0e /* SIGILL */ }, /* performance monitor */
60 { 0x2900, 0x08 /* SIGFPE */ }, /* apu unavailable */
61 { 0x3100, 0x0e /* SIGALRM */ }, /* fixed interval timer */
62 { 0x3200, 0x02 /* SIGINT */ }, /* watchdog */
63 #else /* ! CONFIG_FSL_BOOKE */
64 { 0x1000, 0x0e /* SIGALRM */ }, /* prog interval timer */
65 { 0x1010, 0x0e /* SIGALRM */ }, /* fixed interval timer */
66 { 0x1020, 0x02 /* SIGINT */ }, /* watchdog */
67 { 0x2010, 0x08 /* SIGFPE */ }, /* fp unavailable */
68 { 0x2020, 0x08 /* SIGFPE */ }, /* ap unavailable */
69 #endif
70 #else /* !CONFIG_BOOKE_OR_40x */
71 { 0x0d00, 0x05 /* SIGTRAP */ }, /* single-step */
72 #if defined(CONFIG_PPC_8xx)
73 { 0x1000, 0x04 /* SIGILL */ }, /* software emulation */
74 #else /* ! CONFIG_PPC_8xx */
75 { 0x0f00, 0x04 /* SIGILL */ }, /* performance monitor */
76 { 0x0f20, 0x08 /* SIGFPE */ }, /* altivec unavailable */
77 { 0x1300, 0x05 /* SIGTRAP */ }, /* instruction address break */
78 #if defined(CONFIG_PPC64)
79 { 0x1200, 0x05 /* SIGILL */ }, /* system error */
80 { 0x1500, 0x04 /* SIGILL */ }, /* soft patch */
81 { 0x1600, 0x04 /* SIGILL */ }, /* maintenance */
82 { 0x1700, 0x08 /* SIGFPE */ }, /* altivec assist */
83 { 0x1800, 0x04 /* SIGILL */ }, /* thermal */
84 #else /* ! CONFIG_PPC64 */
85 { 0x1400, 0x02 /* SIGINT */ }, /* SMI */
86 { 0x1600, 0x08 /* SIGFPE */ }, /* altivec assist */
87 { 0x1700, 0x04 /* SIGILL */ }, /* TAU */
88 { 0x2000, 0x05 /* SIGTRAP */ }, /* run mode */
89 #endif
90 #endif
91 #endif
92 { 0x0000, 0x00 } /* Must be last */
93 };
94
95 static int computeSignal(unsigned int tt)
96 {
97 struct hard_trap_info *ht;
98
99 for (ht = hard_trap_info; ht->tt && ht->signo; ht++)
100 if (ht->tt == tt)
101 return ht->signo;
102
103 return SIGHUP; /* default for things we don't know about */
104 }
105
106 /**
107 *
108 * kgdb_skipexception - Bail out of KGDB when we've been triggered.
109 * @exception: Exception vector number
110 * @regs: Current &struct pt_regs.
111 *
112 * On some architectures we need to skip a breakpoint exception when
113 * it occurs after a breakpoint has been removed.
114 *
115 */
116 int kgdb_skipexception(int exception, struct pt_regs *regs)
117 {
118 return kgdb_isremovedbreak(regs->nip);
119 }
120
121 static int kgdb_debugger_ipi(struct pt_regs *regs)
122 {
123 kgdb_nmicallback(raw_smp_processor_id(), regs);
124 return 0;
125 }
126
127 #ifdef CONFIG_SMP
128 void kgdb_roundup_cpus(void)
129 {
130 smp_send_debugger_break();
131 }
132 #endif
133
134 /* KGDB functions to use existing PowerPC64 hooks. */
135 static int kgdb_debugger(struct pt_regs *regs)
136 {
137 return !kgdb_handle_exception(1, computeSignal(TRAP(regs)),
138 DIE_OOPS, regs);
139 }
140
141 static int kgdb_handle_breakpoint(struct pt_regs *regs)
142 {
143 if (user_mode(regs))
144 return 0;
145
146 if (kgdb_handle_exception(1, SIGTRAP, 0, regs) != 0)
147 return 0;
148
149 if (*(u32 *)regs->nip == BREAK_INSTR)
150 regs_add_return_ip(regs, BREAK_INSTR_SIZE);
151
152 return 1;
153 }
154
155 static int kgdb_singlestep(struct pt_regs *regs)
156 {
157 if (user_mode(regs))
158 return 0;
159
160 kgdb_handle_exception(0, SIGTRAP, 0, regs);
161
162 return 1;
163 }
164
165 static int kgdb_iabr_match(struct pt_regs *regs)
166 {
167 if (user_mode(regs))
168 return 0;
169
170 if (kgdb_handle_exception(0, computeSignal(TRAP(regs)), 0, regs) != 0)
171 return 0;
172 return 1;
173 }
174
175 static int kgdb_break_match(struct pt_regs *regs)
176 {
177 if (user_mode(regs))
178 return 0;
179
180 if (kgdb_handle_exception(0, computeSignal(TRAP(regs)), 0, regs) != 0)
181 return 0;
182 return 1;
183 }
184
185 #define PACK64(ptr, src) do { *(ptr++) = (src); } while (0)
186
187 #define PACK32(ptr, src) do { \
188 u32 *ptr32; \
189 ptr32 = (u32 *)ptr; \
190 *(ptr32++) = (src); \
191 ptr = (unsigned long *)ptr32; \
192 } while (0)
193
194 void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p)
195 {
196 struct pt_regs *regs = (struct pt_regs *)(p->thread.ksp +
197 STACK_FRAME_OVERHEAD);
198 unsigned long *ptr = gdb_regs;
199 int reg;
200
201 memset(gdb_regs, 0, NUMREGBYTES);
202
203 /* Regs GPR0-2 */
204 for (reg = 0; reg < 3; reg++)
205 PACK64(ptr, regs->gpr[reg]);
206
207 /* Regs GPR3-13 are caller saved, not in regs->gpr[] */
208 ptr += 11;
209
210 /* Regs GPR14-31 */
211 for (reg = 14; reg < 32; reg++)
212 PACK64(ptr, regs->gpr[reg]);
213
214 #ifdef CONFIG_FSL_BOOKE
215 #ifdef CONFIG_SPE
216 for (reg = 0; reg < 32; reg++)
217 PACK64(ptr, p->thread.evr[reg]);
218 #else
219 ptr += 32;
220 #endif
221 #else
222 /* fp registers not used by kernel, leave zero */
223 ptr += 32 * 8 / sizeof(long);
224 #endif
225
226 PACK64(ptr, regs->nip);
227 PACK64(ptr, regs->msr);
228 PACK32(ptr, regs->ccr);
229 PACK64(ptr, regs->link);
230 PACK64(ptr, regs->ctr);
231 PACK32(ptr, regs->xer);
232
233 BUG_ON((unsigned long)ptr >
234 (unsigned long)(((void *)gdb_regs) + NUMREGBYTES));
235 }
236
237 #define GDB_SIZEOF_REG sizeof(unsigned long)
238 #define GDB_SIZEOF_REG_U32 sizeof(u32)
239
240 #ifdef CONFIG_FSL_BOOKE
241 #define GDB_SIZEOF_FLOAT_REG sizeof(unsigned long)
242 #else
243 #define GDB_SIZEOF_FLOAT_REG sizeof(u64)
244 #endif
245
246 struct dbg_reg_def_t dbg_reg_def[DBG_MAX_REG_NUM] =
247 {
248 { "r0", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[0]) },
249 { "r1", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[1]) },
250 { "r2", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[2]) },
251 { "r3", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[3]) },
252 { "r4", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[4]) },
253 { "r5", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[5]) },
254 { "r6", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[6]) },
255 { "r7", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[7]) },
256 { "r8", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[8]) },
257 { "r9", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[9]) },
258 { "r10", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[10]) },
259 { "r11", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[11]) },
260 { "r12", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[12]) },
261 { "r13", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[13]) },
262 { "r14", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[14]) },
263 { "r15", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[15]) },
264 { "r16", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[16]) },
265 { "r17", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[17]) },
266 { "r18", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[18]) },
267 { "r19", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[19]) },
268 { "r20", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[20]) },
269 { "r21", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[21]) },
270 { "r22", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[22]) },
271 { "r23", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[23]) },
272 { "r24", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[24]) },
273 { "r25", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[25]) },
274 { "r26", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[26]) },
275 { "r27", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[27]) },
276 { "r28", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[28]) },
277 { "r29", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[29]) },
278 { "r30", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[30]) },
279 { "r31", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[31]) },
280
281 { "f0", GDB_SIZEOF_FLOAT_REG, 0 },
282 { "f1", GDB_SIZEOF_FLOAT_REG, 1 },
283 { "f2", GDB_SIZEOF_FLOAT_REG, 2 },
284 { "f3", GDB_SIZEOF_FLOAT_REG, 3 },
285 { "f4", GDB_SIZEOF_FLOAT_REG, 4 },
286 { "f5", GDB_SIZEOF_FLOAT_REG, 5 },
287 { "f6", GDB_SIZEOF_FLOAT_REG, 6 },
288 { "f7", GDB_SIZEOF_FLOAT_REG, 7 },
289 { "f8", GDB_SIZEOF_FLOAT_REG, 8 },
290 { "f9", GDB_SIZEOF_FLOAT_REG, 9 },
291 { "f10", GDB_SIZEOF_FLOAT_REG, 10 },
292 { "f11", GDB_SIZEOF_FLOAT_REG, 11 },
293 { "f12", GDB_SIZEOF_FLOAT_REG, 12 },
294 { "f13", GDB_SIZEOF_FLOAT_REG, 13 },
295 { "f14", GDB_SIZEOF_FLOAT_REG, 14 },
296 { "f15", GDB_SIZEOF_FLOAT_REG, 15 },
297 { "f16", GDB_SIZEOF_FLOAT_REG, 16 },
298 { "f17", GDB_SIZEOF_FLOAT_REG, 17 },
299 { "f18", GDB_SIZEOF_FLOAT_REG, 18 },
300 { "f19", GDB_SIZEOF_FLOAT_REG, 19 },
301 { "f20", GDB_SIZEOF_FLOAT_REG, 20 },
302 { "f21", GDB_SIZEOF_FLOAT_REG, 21 },
303 { "f22", GDB_SIZEOF_FLOAT_REG, 22 },
304 { "f23", GDB_SIZEOF_FLOAT_REG, 23 },
305 { "f24", GDB_SIZEOF_FLOAT_REG, 24 },
306 { "f25", GDB_SIZEOF_FLOAT_REG, 25 },
307 { "f26", GDB_SIZEOF_FLOAT_REG, 26 },
308 { "f27", GDB_SIZEOF_FLOAT_REG, 27 },
309 { "f28", GDB_SIZEOF_FLOAT_REG, 28 },
310 { "f29", GDB_SIZEOF_FLOAT_REG, 29 },
311 { "f30", GDB_SIZEOF_FLOAT_REG, 30 },
312 { "f31", GDB_SIZEOF_FLOAT_REG, 31 },
313
314 { "pc", GDB_SIZEOF_REG, offsetof(struct pt_regs, nip) },
315 { "msr", GDB_SIZEOF_REG, offsetof(struct pt_regs, msr) },
316 { "cr", GDB_SIZEOF_REG_U32, offsetof(struct pt_regs, ccr) },
317 { "lr", GDB_SIZEOF_REG, offsetof(struct pt_regs, link) },
318 { "ctr", GDB_SIZEOF_REG_U32, offsetof(struct pt_regs, ctr) },
319 { "xer", GDB_SIZEOF_REG, offsetof(struct pt_regs, xer) },
320 };
321
322 char *dbg_get_reg(int regno, void *mem, struct pt_regs *regs)
323 {
324 if (regno >= DBG_MAX_REG_NUM || regno < 0)
325 return NULL;
326
327 if (regno < 32 || regno >= 64)
328 /* First 0 -> 31 gpr registers*/
329 /* pc, msr, ls... registers 64 -> 69 */
330 memcpy(mem, (void *)regs + dbg_reg_def[regno].offset,
331 dbg_reg_def[regno].size);
332
333 if (regno >= 32 && regno < 64) {
334 /* FP registers 32 -> 63 */
335 #if defined(CONFIG_FSL_BOOKE) && defined(CONFIG_SPE)
336 if (current)
337 memcpy(mem, ¤t->thread.evr[regno-32],
338 dbg_reg_def[regno].size);
339 #else
340 /* fp registers not used by kernel, leave zero */
341 memset(mem, 0, dbg_reg_def[regno].size);
342 #endif
343 }
344
345 return dbg_reg_def[regno].name;
346 }
347
348 int dbg_set_reg(int regno, void *mem, struct pt_regs *regs)
349 {
350 if (regno >= DBG_MAX_REG_NUM || regno < 0)
351 return -EINVAL;
352
353 if (regno < 32 || regno >= 64)
354 /* First 0 -> 31 gpr registers*/
355 /* pc, msr, ls... registers 64 -> 69 */
356 memcpy((void *)regs + dbg_reg_def[regno].offset, mem,
357 dbg_reg_def[regno].size);
358
359 if (regno >= 32 && regno < 64) {
360 /* FP registers 32 -> 63 */
361 #if defined(CONFIG_FSL_BOOKE) && defined(CONFIG_SPE)
362 memcpy(¤t->thread.evr[regno-32], mem,
363 dbg_reg_def[regno].size);
364 #else
365 /* fp registers not used by kernel, leave zero */
366 return 0;
367 #endif
368 }
369
370 return 0;
371 }
372
373 void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long pc)
374 {
375 regs_set_return_ip(regs, pc);
376 }
377
378 /*
379 * This function does PowerPC specific processing for interfacing to gdb.
380 */
381 int kgdb_arch_handle_exception(int vector, int signo, int err_code,
382 char *remcom_in_buffer, char *remcom_out_buffer,
383 struct pt_regs *linux_regs)
384 {
385 char *ptr = &remcom_in_buffer[1];
386 unsigned long addr;
387
388 switch (remcom_in_buffer[0]) {
389 /*
390 * sAA..AA Step one instruction from AA..AA
391 * This will return an error to gdb ..
392 */
393 case 's':
394 case 'c':
395 /* handle the optional parameter */
396 if (kgdb_hex2long(&ptr, &addr))
397 regs_set_return_ip(linux_regs, addr);
398
399 atomic_set(&kgdb_cpu_doing_single_step, -1);
400 /* set the trace bit if we're stepping */
401 if (remcom_in_buffer[0] == 's') {
402 #ifdef CONFIG_PPC_ADV_DEBUG_REGS
403 mtspr(SPRN_DBCR0,
404 mfspr(SPRN_DBCR0) | DBCR0_IC | DBCR0_IDM);
405 regs_set_return_msr(linux_regs, linux_regs->msr | MSR_DE);
406 #else
407 regs_set_return_msr(linux_regs, linux_regs->msr | MSR_SE);
408 #endif
409 atomic_set(&kgdb_cpu_doing_single_step,
410 raw_smp_processor_id());
411 }
412 return 0;
413 }
414
415 return -1;
416 }
417
418 int kgdb_arch_set_breakpoint(struct kgdb_bkpt *bpt)
419 {
420 u32 instr, *addr = (u32 *)bpt->bpt_addr;
421 int err;
422
423 err = get_kernel_nofault(instr, addr);
424 if (err)
425 return err;
426
427 err = patch_instruction(addr, ppc_inst(BREAK_INSTR));
428 if (err)
429 return -EFAULT;
430
431 *(u32 *)bpt->saved_instr = instr;
432
433 return 0;
434 }
435
436 int kgdb_arch_remove_breakpoint(struct kgdb_bkpt *bpt)
437 {
438 int err;
439 unsigned int instr = *(unsigned int *)bpt->saved_instr;
440 u32 *addr = (u32 *)bpt->bpt_addr;
441
442 err = patch_instruction(addr, ppc_inst(instr));
443 if (err)
444 return -EFAULT;
445
446 return 0;
447 }
448
449 /*
450 * Global data
451 */
452 const struct kgdb_arch arch_kgdb_ops;
453
454 static int kgdb_not_implemented(struct pt_regs *regs)
455 {
456 return 0;
457 }
458
459 static void *old__debugger_ipi;
460 static void *old__debugger;
461 static void *old__debugger_bpt;
462 static void *old__debugger_sstep;
463 static void *old__debugger_iabr_match;
464 static void *old__debugger_break_match;
465 static void *old__debugger_fault_handler;
466
467 int kgdb_arch_init(void)
468 {
469 old__debugger_ipi = __debugger_ipi;
470 old__debugger = __debugger;
471 old__debugger_bpt = __debugger_bpt;
472 old__debugger_sstep = __debugger_sstep;
473 old__debugger_iabr_match = __debugger_iabr_match;
474 old__debugger_break_match = __debugger_break_match;
475 old__debugger_fault_handler = __debugger_fault_handler;
476
477 __debugger_ipi = kgdb_debugger_ipi;
478 __debugger = kgdb_debugger;
479 __debugger_bpt = kgdb_handle_breakpoint;
480 __debugger_sstep = kgdb_singlestep;
481 __debugger_iabr_match = kgdb_iabr_match;
482 __debugger_break_match = kgdb_break_match;
483 __debugger_fault_handler = kgdb_not_implemented;
484
485 return 0;
486 }
487
488 void kgdb_arch_exit(void)
489 {
490 __debugger_ipi = old__debugger_ipi;
491 __debugger = old__debugger;
492 __debugger_bpt = old__debugger_bpt;
493 __debugger_sstep = old__debugger_sstep;
494 __debugger_iabr_match = old__debugger_iabr_match;
495 __debugger_break_match = old__debugger_break_match;
496 __debugger_fault_handler = old__debugger_fault_handler;
497 }
498
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