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