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/init.h>
19 #include <linux/kgdb.h>
20 #include <linux/smp.h>
21 #include <linux/signal.h>
22 #include <linux/ptrace.h>
23 #include <linux/kdebug.h>
24 #include <asm/current.h>
25 #include <asm/processor.h>
26 #include <asm/machdep.h>
27 #include <asm/debug.h>
28
29 /*
30 * This table contains the mapping between PowerPC hardware trap types, and
31 * signals, which are primarily what GDB understands. GDB and the kernel
32 * don't always agree on values, so we use constants taken from gdb-6.2.
33 */
34 static struct hard_trap_info
35 {
36 unsigned int tt; /* Trap type code for powerpc */
37 unsigned char signo; /* Signal that we map this trap into */
38 } hard_trap_info[] = {
39 { 0x0100, 0x02 /* SIGINT */ }, /* system reset */
40 { 0x0200, 0x0b /* SIGSEGV */ }, /* machine check */
41 { 0x0300, 0x0b /* SIGSEGV */ }, /* data access */
42 { 0x0400, 0x0b /* SIGSEGV */ }, /* instruction access */
43 { 0x0500, 0x02 /* SIGINT */ }, /* external interrupt */
44 { 0x0600, 0x0a /* SIGBUS */ }, /* alignment */
45 { 0x0700, 0x05 /* SIGTRAP */ }, /* program check */
46 { 0x0800, 0x08 /* SIGFPE */ }, /* fp unavailable */
47 { 0x0900, 0x0e /* SIGALRM */ }, /* decrementer */
48 { 0x0c00, 0x14 /* SIGCHLD */ }, /* system call */
49 #if defined(CONFIG_40x) || defined(CONFIG_BOOKE)
50 { 0x2002, 0x05 /* SIGTRAP */ }, /* debug */
51 #if defined(CONFIG_FSL_BOOKE)
52 { 0x2010, 0x08 /* SIGFPE */ }, /* spe unavailable */
53 { 0x2020, 0x08 /* SIGFPE */ }, /* spe unavailable */
54 { 0x2030, 0x08 /* SIGFPE */ }, /* spe fp data */
55 { 0x2040, 0x08 /* SIGFPE */ }, /* spe fp data */
56 { 0x2050, 0x08 /* SIGFPE */ }, /* spe fp round */
57 { 0x2060, 0x0e /* SIGILL */ }, /* performance monitor */
58 { 0x2900, 0x08 /* SIGFPE */ }, /* apu unavailable */
59 { 0x3100, 0x0e /* SIGALRM */ }, /* fixed interval timer */
60 { 0x3200, 0x02 /* SIGINT */ }, /* watchdog */
61 #else /* ! CONFIG_FSL_BOOKE */
62 { 0x1000, 0x0e /* SIGALRM */ }, /* prog interval timer */
63 { 0x1010, 0x0e /* SIGALRM */ }, /* fixed interval timer */
64 { 0x1020, 0x02 /* SIGINT */ }, /* watchdog */
65 { 0x2010, 0x08 /* SIGFPE */ }, /* fp unavailable */
66 { 0x2020, 0x08 /* SIGFPE */ }, /* ap unavailable */
67 #endif
68 #else /* ! (defined(CONFIG_40x) || defined(CONFIG_BOOKE)) */
69 { 0x0d00, 0x05 /* SIGTRAP */ }, /* single-step */
70 #if defined(CONFIG_8xx)
71 { 0x1000, 0x04 /* SIGILL */ }, /* software emulation */
72 #else /* ! CONFIG_8xx */
73 { 0x0f00, 0x04 /* SIGILL */ }, /* performance monitor */
74 { 0x0f20, 0x08 /* SIGFPE */ }, /* altivec unavailable */
75 { 0x1300, 0x05 /* SIGTRAP */ }, /* instruction address break */
76 #if defined(CONFIG_PPC64)
77 { 0x1200, 0x05 /* SIGILL */ }, /* system error */
78 { 0x1500, 0x04 /* SIGILL */ }, /* soft patch */
79 { 0x1600, 0x04 /* SIGILL */ }, /* maintenance */
80 { 0x1700, 0x08 /* SIGFPE */ }, /* altivec assist */
81 { 0x1800, 0x04 /* SIGILL */ }, /* thermal */
82 #else /* ! CONFIG_PPC64 */
83 { 0x1400, 0x02 /* SIGINT */ }, /* SMI */
84 { 0x1600, 0x08 /* SIGFPE */ }, /* altivec assist */
85 { 0x1700, 0x04 /* SIGILL */ }, /* TAU */
86 { 0x2000, 0x05 /* SIGTRAP */ }, /* run mode */
87 #endif
88 #endif
89 #endif
90 { 0x0000, 0x00 } /* Must be last */
91 };
92
computeSignal(unsigned int tt)93 static int computeSignal(unsigned int tt)
94 {
95 struct hard_trap_info *ht;
96
97 for (ht = hard_trap_info; ht->tt && ht->signo; ht++)
98 if (ht->tt == tt)
99 return ht->signo;
100
101 return SIGHUP; /* default for things we don't know about */
102 }
103
kgdb_call_nmi_hook(struct pt_regs * regs)104 static int kgdb_call_nmi_hook(struct pt_regs *regs)
105 {
106 kgdb_nmicallback(raw_smp_processor_id(), regs);
107 return 0;
108 }
109
110 #ifdef CONFIG_SMP
kgdb_roundup_cpus(unsigned long flags)111 void kgdb_roundup_cpus(unsigned long flags)
112 {
113 smp_send_debugger_break();
114 }
115 #endif
116
117 /* KGDB functions to use existing PowerPC64 hooks. */
kgdb_debugger(struct pt_regs * regs)118 static int kgdb_debugger(struct pt_regs *regs)
119 {
120 return !kgdb_handle_exception(1, computeSignal(TRAP(regs)),
121 DIE_OOPS, regs);
122 }
123
kgdb_handle_breakpoint(struct pt_regs * regs)124 static int kgdb_handle_breakpoint(struct pt_regs *regs)
125 {
126 if (user_mode(regs))
127 return 0;
128
129 if (kgdb_handle_exception(1, SIGTRAP, 0, regs) != 0)
130 return 0;
131
132 if (*(u32 *) (regs->nip) == *(u32 *) (&arch_kgdb_ops.gdb_bpt_instr))
133 regs->nip += BREAK_INSTR_SIZE;
134
135 return 1;
136 }
137
kgdb_singlestep(struct pt_regs * regs)138 static int kgdb_singlestep(struct pt_regs *regs)
139 {
140 struct thread_info *thread_info, *exception_thread_info;
141
142 if (user_mode(regs))
143 return 0;
144
145 /*
146 * On Book E and perhaps other processors, singlestep is handled on
147 * the critical exception stack. This causes current_thread_info()
148 * to fail, since it it locates the thread_info by masking off
149 * the low bits of the current stack pointer. We work around
150 * this issue by copying the thread_info from the kernel stack
151 * before calling kgdb_handle_exception, and copying it back
152 * afterwards. On most processors the copy is avoided since
153 * exception_thread_info == thread_info.
154 */
155 thread_info = (struct thread_info *)(regs->gpr[1] & ~(THREAD_SIZE-1));
156 exception_thread_info = current_thread_info();
157
158 if (thread_info != exception_thread_info)
159 memcpy(exception_thread_info, thread_info, sizeof *thread_info);
160
161 kgdb_handle_exception(0, SIGTRAP, 0, regs);
162
163 if (thread_info != exception_thread_info)
164 memcpy(thread_info, exception_thread_info, sizeof *thread_info);
165
166 return 1;
167 }
168
kgdb_iabr_match(struct pt_regs * regs)169 static int kgdb_iabr_match(struct pt_regs *regs)
170 {
171 if (user_mode(regs))
172 return 0;
173
174 if (kgdb_handle_exception(0, computeSignal(TRAP(regs)), 0, regs) != 0)
175 return 0;
176 return 1;
177 }
178
kgdb_dabr_match(struct pt_regs * regs)179 static int kgdb_dabr_match(struct pt_regs *regs)
180 {
181 if (user_mode(regs))
182 return 0;
183
184 if (kgdb_handle_exception(0, computeSignal(TRAP(regs)), 0, regs) != 0)
185 return 0;
186 return 1;
187 }
188
189 #define PACK64(ptr, src) do { *(ptr++) = (src); } while (0)
190
191 #define PACK32(ptr, src) do { \
192 u32 *ptr32; \
193 ptr32 = (u32 *)ptr; \
194 *(ptr32++) = (src); \
195 ptr = (unsigned long *)ptr32; \
196 } while (0)
197
sleeping_thread_to_gdb_regs(unsigned long * gdb_regs,struct task_struct * p)198 void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p)
199 {
200 struct pt_regs *regs = (struct pt_regs *)(p->thread.ksp +
201 STACK_FRAME_OVERHEAD);
202 unsigned long *ptr = gdb_regs;
203 int reg;
204
205 memset(gdb_regs, 0, NUMREGBYTES);
206
207 /* Regs GPR0-2 */
208 for (reg = 0; reg < 3; reg++)
209 PACK64(ptr, regs->gpr[reg]);
210
211 /* Regs GPR3-13 are caller saved, not in regs->gpr[] */
212 ptr += 11;
213
214 /* Regs GPR14-31 */
215 for (reg = 14; reg < 32; reg++)
216 PACK64(ptr, regs->gpr[reg]);
217
218 #ifdef CONFIG_FSL_BOOKE
219 #ifdef CONFIG_SPE
220 for (reg = 0; reg < 32; reg++)
221 PACK64(ptr, p->thread.evr[reg]);
222 #else
223 ptr += 32;
224 #endif
225 #else
226 /* fp registers not used by kernel, leave zero */
227 ptr += 32 * 8 / sizeof(long);
228 #endif
229
230 PACK64(ptr, regs->nip);
231 PACK64(ptr, regs->msr);
232 PACK32(ptr, regs->ccr);
233 PACK64(ptr, regs->link);
234 PACK64(ptr, regs->ctr);
235 PACK32(ptr, regs->xer);
236
237 BUG_ON((unsigned long)ptr >
238 (unsigned long)(((void *)gdb_regs) + NUMREGBYTES));
239 }
240
241 #define GDB_SIZEOF_REG sizeof(unsigned long)
242 #define GDB_SIZEOF_REG_U32 sizeof(u32)
243
244 #ifdef CONFIG_FSL_BOOKE
245 #define GDB_SIZEOF_FLOAT_REG sizeof(unsigned long)
246 #else
247 #define GDB_SIZEOF_FLOAT_REG sizeof(u64)
248 #endif
249
250 struct dbg_reg_def_t dbg_reg_def[DBG_MAX_REG_NUM] =
251 {
252 { "r0", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[0]) },
253 { "r1", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[1]) },
254 { "r2", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[2]) },
255 { "r3", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[3]) },
256 { "r4", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[4]) },
257 { "r5", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[5]) },
258 { "r6", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[6]) },
259 { "r7", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[7]) },
260 { "r8", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[8]) },
261 { "r9", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[9]) },
262 { "r10", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[10]) },
263 { "r11", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[11]) },
264 { "r12", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[12]) },
265 { "r13", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[13]) },
266 { "r14", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[14]) },
267 { "r15", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[15]) },
268 { "r16", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[16]) },
269 { "r17", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[17]) },
270 { "r18", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[18]) },
271 { "r19", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[19]) },
272 { "r20", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[20]) },
273 { "r21", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[21]) },
274 { "r22", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[22]) },
275 { "r23", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[23]) },
276 { "r24", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[24]) },
277 { "r25", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[25]) },
278 { "r26", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[26]) },
279 { "r27", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[27]) },
280 { "r28", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[28]) },
281 { "r29", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[29]) },
282 { "r30", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[30]) },
283 { "r31", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[31]) },
284
285 { "f0", GDB_SIZEOF_FLOAT_REG, 0 },
286 { "f1", GDB_SIZEOF_FLOAT_REG, 1 },
287 { "f2", GDB_SIZEOF_FLOAT_REG, 2 },
288 { "f3", GDB_SIZEOF_FLOAT_REG, 3 },
289 { "f4", GDB_SIZEOF_FLOAT_REG, 4 },
290 { "f5", GDB_SIZEOF_FLOAT_REG, 5 },
291 { "f6", GDB_SIZEOF_FLOAT_REG, 6 },
292 { "f7", GDB_SIZEOF_FLOAT_REG, 7 },
293 { "f8", GDB_SIZEOF_FLOAT_REG, 8 },
294 { "f9", GDB_SIZEOF_FLOAT_REG, 9 },
295 { "f10", GDB_SIZEOF_FLOAT_REG, 10 },
296 { "f11", GDB_SIZEOF_FLOAT_REG, 11 },
297 { "f12", GDB_SIZEOF_FLOAT_REG, 12 },
298 { "f13", GDB_SIZEOF_FLOAT_REG, 13 },
299 { "f14", GDB_SIZEOF_FLOAT_REG, 14 },
300 { "f15", GDB_SIZEOF_FLOAT_REG, 15 },
301 { "f16", GDB_SIZEOF_FLOAT_REG, 16 },
302 { "f17", GDB_SIZEOF_FLOAT_REG, 17 },
303 { "f18", GDB_SIZEOF_FLOAT_REG, 18 },
304 { "f19", GDB_SIZEOF_FLOAT_REG, 19 },
305 { "f20", GDB_SIZEOF_FLOAT_REG, 20 },
306 { "f21", GDB_SIZEOF_FLOAT_REG, 21 },
307 { "f22", GDB_SIZEOF_FLOAT_REG, 22 },
308 { "f23", GDB_SIZEOF_FLOAT_REG, 23 },
309 { "f24", GDB_SIZEOF_FLOAT_REG, 24 },
310 { "f25", GDB_SIZEOF_FLOAT_REG, 25 },
311 { "f26", GDB_SIZEOF_FLOAT_REG, 26 },
312 { "f27", GDB_SIZEOF_FLOAT_REG, 27 },
313 { "f28", GDB_SIZEOF_FLOAT_REG, 28 },
314 { "f29", GDB_SIZEOF_FLOAT_REG, 29 },
315 { "f30", GDB_SIZEOF_FLOAT_REG, 30 },
316 { "f31", GDB_SIZEOF_FLOAT_REG, 31 },
317
318 { "pc", GDB_SIZEOF_REG, offsetof(struct pt_regs, nip) },
319 { "msr", GDB_SIZEOF_REG, offsetof(struct pt_regs, msr) },
320 { "cr", GDB_SIZEOF_REG_U32, offsetof(struct pt_regs, ccr) },
321 { "lr", GDB_SIZEOF_REG, offsetof(struct pt_regs, link) },
322 { "ctr", GDB_SIZEOF_REG_U32, offsetof(struct pt_regs, ctr) },
323 { "xer", GDB_SIZEOF_REG, offsetof(struct pt_regs, xer) },
324 };
325
dbg_get_reg(int regno,void * mem,struct pt_regs * regs)326 char *dbg_get_reg(int regno, void *mem, struct pt_regs *regs)
327 {
328 if (regno >= DBG_MAX_REG_NUM || regno < 0)
329 return NULL;
330
331 if (regno < 32 || regno >= 64)
332 /* First 0 -> 31 gpr registers*/
333 /* pc, msr, ls... registers 64 -> 69 */
334 memcpy(mem, (void *)regs + dbg_reg_def[regno].offset,
335 dbg_reg_def[regno].size);
336
337 if (regno >= 32 && regno < 64) {
338 /* FP registers 32 -> 63 */
339 #if defined(CONFIG_FSL_BOOKE) && defined(CONFIG_SPE)
340 if (current)
341 memcpy(mem, ¤t->thread.evr[regno-32],
342 dbg_reg_def[regno].size);
343 #else
344 /* fp registers not used by kernel, leave zero */
345 memset(mem, 0, dbg_reg_def[regno].size);
346 #endif
347 }
348
349 return dbg_reg_def[regno].name;
350 }
351
dbg_set_reg(int regno,void * mem,struct pt_regs * regs)352 int dbg_set_reg(int regno, void *mem, struct pt_regs *regs)
353 {
354 if (regno >= DBG_MAX_REG_NUM || regno < 0)
355 return -EINVAL;
356
357 if (regno < 32 || regno >= 64)
358 /* First 0 -> 31 gpr registers*/
359 /* pc, msr, ls... registers 64 -> 69 */
360 memcpy((void *)regs + dbg_reg_def[regno].offset, mem,
361 dbg_reg_def[regno].size);
362
363 if (regno >= 32 && regno < 64) {
364 /* FP registers 32 -> 63 */
365 #if defined(CONFIG_FSL_BOOKE) && defined(CONFIG_SPE)
366 memcpy(¤t->thread.evr[regno-32], mem,
367 dbg_reg_def[regno].size);
368 #else
369 /* fp registers not used by kernel, leave zero */
370 return 0;
371 #endif
372 }
373
374 return 0;
375 }
376
kgdb_arch_set_pc(struct pt_regs * regs,unsigned long pc)377 void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long pc)
378 {
379 regs->nip = pc;
380 }
381
382 /*
383 * This function does PowerPC specific procesing for interfacing to gdb.
384 */
kgdb_arch_handle_exception(int vector,int signo,int err_code,char * remcom_in_buffer,char * remcom_out_buffer,struct pt_regs * linux_regs)385 int kgdb_arch_handle_exception(int vector, int signo, int err_code,
386 char *remcom_in_buffer, char *remcom_out_buffer,
387 struct pt_regs *linux_regs)
388 {
389 char *ptr = &remcom_in_buffer[1];
390 unsigned long addr;
391
392 switch (remcom_in_buffer[0]) {
393 /*
394 * sAA..AA Step one instruction from AA..AA
395 * This will return an error to gdb ..
396 */
397 case 's':
398 case 'c':
399 /* handle the optional parameter */
400 if (kgdb_hex2long(&ptr, &addr))
401 linux_regs->nip = addr;
402
403 atomic_set(&kgdb_cpu_doing_single_step, -1);
404 /* set the trace bit if we're stepping */
405 if (remcom_in_buffer[0] == 's') {
406 #ifdef CONFIG_PPC_ADV_DEBUG_REGS
407 mtspr(SPRN_DBCR0,
408 mfspr(SPRN_DBCR0) | DBCR0_IC | DBCR0_IDM);
409 linux_regs->msr |= MSR_DE;
410 #else
411 linux_regs->msr |= MSR_SE;
412 #endif
413 kgdb_single_step = 1;
414 atomic_set(&kgdb_cpu_doing_single_step,
415 raw_smp_processor_id());
416 }
417 return 0;
418 }
419
420 return -1;
421 }
422
423 /*
424 * Global data
425 */
426 struct kgdb_arch arch_kgdb_ops = {
427 .gdb_bpt_instr = {0x7d, 0x82, 0x10, 0x08},
428 };
429
kgdb_not_implemented(struct pt_regs * regs)430 static int kgdb_not_implemented(struct pt_regs *regs)
431 {
432 return 0;
433 }
434
435 static void *old__debugger_ipi;
436 static void *old__debugger;
437 static void *old__debugger_bpt;
438 static void *old__debugger_sstep;
439 static void *old__debugger_iabr_match;
440 static void *old__debugger_dabr_match;
441 static void *old__debugger_fault_handler;
442
kgdb_arch_init(void)443 int kgdb_arch_init(void)
444 {
445 old__debugger_ipi = __debugger_ipi;
446 old__debugger = __debugger;
447 old__debugger_bpt = __debugger_bpt;
448 old__debugger_sstep = __debugger_sstep;
449 old__debugger_iabr_match = __debugger_iabr_match;
450 old__debugger_dabr_match = __debugger_dabr_match;
451 old__debugger_fault_handler = __debugger_fault_handler;
452
453 __debugger_ipi = kgdb_call_nmi_hook;
454 __debugger = kgdb_debugger;
455 __debugger_bpt = kgdb_handle_breakpoint;
456 __debugger_sstep = kgdb_singlestep;
457 __debugger_iabr_match = kgdb_iabr_match;
458 __debugger_dabr_match = kgdb_dabr_match;
459 __debugger_fault_handler = kgdb_not_implemented;
460
461 return 0;
462 }
463
kgdb_arch_exit(void)464 void kgdb_arch_exit(void)
465 {
466 __debugger_ipi = old__debugger_ipi;
467 __debugger = old__debugger;
468 __debugger_bpt = old__debugger_bpt;
469 __debugger_sstep = old__debugger_sstep;
470 __debugger_iabr_match = old__debugger_iabr_match;
471 __debugger_dabr_match = old__debugger_dabr_match;
472 __debugger_fault_handler = old__debugger_fault_handler;
473 }
474