1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * PowerPC backend to the KGDB stub.
4 *
5 * 1998 (c) Michael AK Tesch (tesch@cs.wisc.edu)
6 * Copyright (C) 2003 Timesys Corporation.
7 * Copyright (C) 2004-2006 MontaVista Software, Inc.
8 * PPC64 Mods (C) 2005 Frank Rowand (frowand@mvista.com)
9 * PPC32 support restored by Vitaly Wool <vwool@ru.mvista.com> and
10 * Sergei Shtylyov <sshtylyov@ru.mvista.com>
11 * Copyright (C) 2007-2008 Wind River Systems, Inc.
12 */
13
14 #include <linux/kernel.h>
15 #include <linux/kgdb.h>
16 #include <linux/smp.h>
17 #include <linux/signal.h>
18 #include <linux/ptrace.h>
19 #include <linux/kdebug.h>
20 #include <asm/current.h>
21 #include <asm/processor.h>
22 #include <asm/machdep.h>
23 #include <asm/debug.h>
24 #include <asm/code-patching.h>
25 #include <linux/slab.h>
26 #include <asm/inst.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 #ifdef CONFIG_BOOKE_OR_40x
49 { 0x2002, 0x05 /* SIGTRAP */ }, /* debug */
50 #if defined(CONFIG_PPC_85xx)
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_PPC_85xx */
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 /* !CONFIG_BOOKE_OR_40x */
68 { 0x0d00, 0x05 /* SIGTRAP */ }, /* single-step */
69 #if defined(CONFIG_PPC_8xx)
70 { 0x1000, 0x04 /* SIGILL */ }, /* software emulation */
71 #else /* ! CONFIG_PPC_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
103 /**
104 *
105 * kgdb_skipexception - Bail out of KGDB when we've been triggered.
106 * @exception: Exception vector number
107 * @regs: Current &struct pt_regs.
108 *
109 * On some architectures we need to skip a breakpoint exception when
110 * it occurs after a breakpoint has been removed.
111 *
112 */
kgdb_skipexception(int exception,struct pt_regs * regs)113 int kgdb_skipexception(int exception, struct pt_regs *regs)
114 {
115 return kgdb_isremovedbreak(regs->nip);
116 }
117
kgdb_debugger_ipi(struct pt_regs * regs)118 static int kgdb_debugger_ipi(struct pt_regs *regs)
119 {
120 kgdb_nmicallback(raw_smp_processor_id(), regs);
121 return 0;
122 }
123
124 #ifdef CONFIG_SMP
kgdb_roundup_cpus(void)125 void kgdb_roundup_cpus(void)
126 {
127 smp_send_debugger_break();
128 }
129 #endif
130
131 /* KGDB functions to use existing PowerPC64 hooks. */
kgdb_debugger(struct pt_regs * regs)132 static int kgdb_debugger(struct pt_regs *regs)
133 {
134 return !kgdb_handle_exception(1, computeSignal(TRAP(regs)),
135 DIE_OOPS, regs);
136 }
137
kgdb_handle_breakpoint(struct pt_regs * regs)138 static int kgdb_handle_breakpoint(struct pt_regs *regs)
139 {
140 if (user_mode(regs))
141 return 0;
142
143 if (kgdb_handle_exception(1, SIGTRAP, 0, regs) != 0)
144 return 0;
145
146 if (*(u32 *)regs->nip == BREAK_INSTR)
147 regs_add_return_ip(regs, BREAK_INSTR_SIZE);
148
149 return 1;
150 }
151
kgdb_singlestep(struct pt_regs * regs)152 static int kgdb_singlestep(struct pt_regs *regs)
153 {
154 if (user_mode(regs))
155 return 0;
156
157 kgdb_handle_exception(0, SIGTRAP, 0, regs);
158
159 return 1;
160 }
161
kgdb_iabr_match(struct pt_regs * regs)162 static int kgdb_iabr_match(struct pt_regs *regs)
163 {
164 if (user_mode(regs))
165 return 0;
166
167 if (kgdb_handle_exception(0, computeSignal(TRAP(regs)), 0, regs) != 0)
168 return 0;
169 return 1;
170 }
171
kgdb_break_match(struct pt_regs * regs)172 static int kgdb_break_match(struct pt_regs *regs)
173 {
174 if (user_mode(regs))
175 return 0;
176
177 if (kgdb_handle_exception(0, computeSignal(TRAP(regs)), 0, regs) != 0)
178 return 0;
179 return 1;
180 }
181
182 #define PACK64(ptr, src) do { *(ptr++) = (src); } while (0)
183
184 #define PACK32(ptr, src) do { \
185 u32 *ptr32; \
186 ptr32 = (u32 *)ptr; \
187 *(ptr32++) = (src); \
188 ptr = (unsigned long *)ptr32; \
189 } while (0)
190
sleeping_thread_to_gdb_regs(unsigned long * gdb_regs,struct task_struct * p)191 void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p)
192 {
193 struct pt_regs *regs = (struct pt_regs *)(p->thread.ksp +
194 STACK_INT_FRAME_REGS);
195 unsigned long *ptr = gdb_regs;
196 int reg;
197
198 memset(gdb_regs, 0, NUMREGBYTES);
199
200 /* Regs GPR0-2 */
201 for (reg = 0; reg < 3; reg++)
202 PACK64(ptr, regs->gpr[reg]);
203
204 /* Regs GPR3-13 are caller saved, not in regs->gpr[] */
205 ptr += 11;
206
207 /* Regs GPR14-31 */
208 for (reg = 14; reg < 32; reg++)
209 PACK64(ptr, regs->gpr[reg]);
210
211 #ifdef CONFIG_PPC_85xx
212 #ifdef CONFIG_SPE
213 for (reg = 0; reg < 32; reg++)
214 PACK64(ptr, p->thread.evr[reg]);
215 #else
216 ptr += 32;
217 #endif
218 #else
219 /* fp registers not used by kernel, leave zero */
220 ptr += 32 * 8 / sizeof(long);
221 #endif
222
223 PACK64(ptr, regs->nip);
224 PACK64(ptr, regs->msr);
225 PACK32(ptr, regs->ccr);
226 PACK64(ptr, regs->link);
227 PACK64(ptr, regs->ctr);
228 PACK32(ptr, regs->xer);
229
230 BUG_ON((unsigned long)ptr >
231 (unsigned long)(((void *)gdb_regs) + NUMREGBYTES));
232 }
233
234 #define GDB_SIZEOF_REG sizeof(unsigned long)
235 #define GDB_SIZEOF_REG_U32 sizeof(u32)
236
237 #ifdef CONFIG_PPC_85xx
238 #define GDB_SIZEOF_FLOAT_REG sizeof(unsigned long)
239 #else
240 #define GDB_SIZEOF_FLOAT_REG sizeof(u64)
241 #endif
242
243 struct dbg_reg_def_t dbg_reg_def[DBG_MAX_REG_NUM] =
244 {
245 { "r0", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[0]) },
246 { "r1", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[1]) },
247 { "r2", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[2]) },
248 { "r3", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[3]) },
249 { "r4", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[4]) },
250 { "r5", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[5]) },
251 { "r6", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[6]) },
252 { "r7", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[7]) },
253 { "r8", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[8]) },
254 { "r9", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[9]) },
255 { "r10", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[10]) },
256 { "r11", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[11]) },
257 { "r12", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[12]) },
258 { "r13", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[13]) },
259 { "r14", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[14]) },
260 { "r15", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[15]) },
261 { "r16", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[16]) },
262 { "r17", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[17]) },
263 { "r18", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[18]) },
264 { "r19", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[19]) },
265 { "r20", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[20]) },
266 { "r21", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[21]) },
267 { "r22", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[22]) },
268 { "r23", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[23]) },
269 { "r24", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[24]) },
270 { "r25", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[25]) },
271 { "r26", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[26]) },
272 { "r27", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[27]) },
273 { "r28", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[28]) },
274 { "r29", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[29]) },
275 { "r30", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[30]) },
276 { "r31", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[31]) },
277
278 { "f0", GDB_SIZEOF_FLOAT_REG, 0 },
279 { "f1", GDB_SIZEOF_FLOAT_REG, 1 },
280 { "f2", GDB_SIZEOF_FLOAT_REG, 2 },
281 { "f3", GDB_SIZEOF_FLOAT_REG, 3 },
282 { "f4", GDB_SIZEOF_FLOAT_REG, 4 },
283 { "f5", GDB_SIZEOF_FLOAT_REG, 5 },
284 { "f6", GDB_SIZEOF_FLOAT_REG, 6 },
285 { "f7", GDB_SIZEOF_FLOAT_REG, 7 },
286 { "f8", GDB_SIZEOF_FLOAT_REG, 8 },
287 { "f9", GDB_SIZEOF_FLOAT_REG, 9 },
288 { "f10", GDB_SIZEOF_FLOAT_REG, 10 },
289 { "f11", GDB_SIZEOF_FLOAT_REG, 11 },
290 { "f12", GDB_SIZEOF_FLOAT_REG, 12 },
291 { "f13", GDB_SIZEOF_FLOAT_REG, 13 },
292 { "f14", GDB_SIZEOF_FLOAT_REG, 14 },
293 { "f15", GDB_SIZEOF_FLOAT_REG, 15 },
294 { "f16", GDB_SIZEOF_FLOAT_REG, 16 },
295 { "f17", GDB_SIZEOF_FLOAT_REG, 17 },
296 { "f18", GDB_SIZEOF_FLOAT_REG, 18 },
297 { "f19", GDB_SIZEOF_FLOAT_REG, 19 },
298 { "f20", GDB_SIZEOF_FLOAT_REG, 20 },
299 { "f21", GDB_SIZEOF_FLOAT_REG, 21 },
300 { "f22", GDB_SIZEOF_FLOAT_REG, 22 },
301 { "f23", GDB_SIZEOF_FLOAT_REG, 23 },
302 { "f24", GDB_SIZEOF_FLOAT_REG, 24 },
303 { "f25", GDB_SIZEOF_FLOAT_REG, 25 },
304 { "f26", GDB_SIZEOF_FLOAT_REG, 26 },
305 { "f27", GDB_SIZEOF_FLOAT_REG, 27 },
306 { "f28", GDB_SIZEOF_FLOAT_REG, 28 },
307 { "f29", GDB_SIZEOF_FLOAT_REG, 29 },
308 { "f30", GDB_SIZEOF_FLOAT_REG, 30 },
309 { "f31", GDB_SIZEOF_FLOAT_REG, 31 },
310
311 { "pc", GDB_SIZEOF_REG, offsetof(struct pt_regs, nip) },
312 { "msr", GDB_SIZEOF_REG, offsetof(struct pt_regs, msr) },
313 { "cr", GDB_SIZEOF_REG_U32, offsetof(struct pt_regs, ccr) },
314 { "lr", GDB_SIZEOF_REG, offsetof(struct pt_regs, link) },
315 { "ctr", GDB_SIZEOF_REG_U32, offsetof(struct pt_regs, ctr) },
316 { "xer", GDB_SIZEOF_REG, offsetof(struct pt_regs, xer) },
317 };
318
dbg_get_reg(int regno,void * mem,struct pt_regs * regs)319 char *dbg_get_reg(int regno, void *mem, struct pt_regs *regs)
320 {
321 if (regno >= DBG_MAX_REG_NUM || regno < 0)
322 return NULL;
323
324 if (regno < 32 || regno >= 64)
325 /* First 0 -> 31 gpr registers*/
326 /* pc, msr, ls... registers 64 -> 69 */
327 memcpy(mem, (void *)regs + dbg_reg_def[regno].offset,
328 dbg_reg_def[regno].size);
329
330 if (regno >= 32 && regno < 64) {
331 /* FP registers 32 -> 63 */
332 #if defined(CONFIG_PPC_85xx) && defined(CONFIG_SPE)
333 if (current)
334 memcpy(mem, ¤t->thread.evr[regno-32],
335 dbg_reg_def[regno].size);
336 #else
337 /* fp registers not used by kernel, leave zero */
338 memset(mem, 0, dbg_reg_def[regno].size);
339 #endif
340 }
341
342 return dbg_reg_def[regno].name;
343 }
344
dbg_set_reg(int regno,void * mem,struct pt_regs * regs)345 int dbg_set_reg(int regno, void *mem, struct pt_regs *regs)
346 {
347 if (regno >= DBG_MAX_REG_NUM || regno < 0)
348 return -EINVAL;
349
350 if (regno < 32 || regno >= 64)
351 /* First 0 -> 31 gpr registers*/
352 /* pc, msr, ls... registers 64 -> 69 */
353 memcpy((void *)regs + dbg_reg_def[regno].offset, mem,
354 dbg_reg_def[regno].size);
355
356 if (regno >= 32 && regno < 64) {
357 /* FP registers 32 -> 63 */
358 #if defined(CONFIG_PPC_85xx) && defined(CONFIG_SPE)
359 memcpy(¤t->thread.evr[regno-32], mem,
360 dbg_reg_def[regno].size);
361 #else
362 /* fp registers not used by kernel, leave zero */
363 return 0;
364 #endif
365 }
366
367 return 0;
368 }
369
kgdb_arch_set_pc(struct pt_regs * regs,unsigned long pc)370 void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long pc)
371 {
372 regs_set_return_ip(regs, pc);
373 }
374
375 /*
376 * This function does PowerPC specific processing for interfacing to gdb.
377 */
kgdb_arch_handle_exception(int vector,int signo,int err_code,char * remcom_in_buffer,char * remcom_out_buffer,struct pt_regs * linux_regs)378 int kgdb_arch_handle_exception(int vector, int signo, int err_code,
379 char *remcom_in_buffer, char *remcom_out_buffer,
380 struct pt_regs *linux_regs)
381 {
382 char *ptr = &remcom_in_buffer[1];
383 unsigned long addr;
384
385 switch (remcom_in_buffer[0]) {
386 /*
387 * sAA..AA Step one instruction from AA..AA
388 * This will return an error to gdb ..
389 */
390 case 's':
391 case 'c':
392 /* handle the optional parameter */
393 if (kgdb_hex2long(&ptr, &addr))
394 regs_set_return_ip(linux_regs, addr);
395
396 atomic_set(&kgdb_cpu_doing_single_step, -1);
397 /* set the trace bit if we're stepping */
398 if (remcom_in_buffer[0] == 's') {
399 #ifdef CONFIG_PPC_ADV_DEBUG_REGS
400 mtspr(SPRN_DBCR0,
401 mfspr(SPRN_DBCR0) | DBCR0_IC | DBCR0_IDM);
402 regs_set_return_msr(linux_regs, linux_regs->msr | MSR_DE);
403 #else
404 regs_set_return_msr(linux_regs, linux_regs->msr | MSR_SE);
405 #endif
406 atomic_set(&kgdb_cpu_doing_single_step,
407 raw_smp_processor_id());
408 }
409 return 0;
410 }
411
412 return -1;
413 }
414
kgdb_arch_set_breakpoint(struct kgdb_bkpt * bpt)415 int kgdb_arch_set_breakpoint(struct kgdb_bkpt *bpt)
416 {
417 u32 instr, *addr = (u32 *)bpt->bpt_addr;
418 int err;
419
420 err = get_kernel_nofault(instr, addr);
421 if (err)
422 return err;
423
424 err = patch_instruction(addr, ppc_inst(BREAK_INSTR));
425 if (err)
426 return -EFAULT;
427
428 *(u32 *)bpt->saved_instr = instr;
429
430 return 0;
431 }
432
kgdb_arch_remove_breakpoint(struct kgdb_bkpt * bpt)433 int kgdb_arch_remove_breakpoint(struct kgdb_bkpt *bpt)
434 {
435 int err;
436 unsigned int instr = *(unsigned int *)bpt->saved_instr;
437 u32 *addr = (u32 *)bpt->bpt_addr;
438
439 err = patch_instruction(addr, ppc_inst(instr));
440 if (err)
441 return -EFAULT;
442
443 return 0;
444 }
445
446 /*
447 * Global data
448 */
449 const struct kgdb_arch arch_kgdb_ops;
450
kgdb_not_implemented(struct pt_regs * regs)451 static int kgdb_not_implemented(struct pt_regs *regs)
452 {
453 return 0;
454 }
455
456 static void *old__debugger_ipi;
457 static void *old__debugger;
458 static void *old__debugger_bpt;
459 static void *old__debugger_sstep;
460 static void *old__debugger_iabr_match;
461 static void *old__debugger_break_match;
462 static void *old__debugger_fault_handler;
463
kgdb_arch_init(void)464 int kgdb_arch_init(void)
465 {
466 old__debugger_ipi = __debugger_ipi;
467 old__debugger = __debugger;
468 old__debugger_bpt = __debugger_bpt;
469 old__debugger_sstep = __debugger_sstep;
470 old__debugger_iabr_match = __debugger_iabr_match;
471 old__debugger_break_match = __debugger_break_match;
472 old__debugger_fault_handler = __debugger_fault_handler;
473
474 __debugger_ipi = kgdb_debugger_ipi;
475 __debugger = kgdb_debugger;
476 __debugger_bpt = kgdb_handle_breakpoint;
477 __debugger_sstep = kgdb_singlestep;
478 __debugger_iabr_match = kgdb_iabr_match;
479 __debugger_break_match = kgdb_break_match;
480 __debugger_fault_handler = kgdb_not_implemented;
481
482 return 0;
483 }
484
kgdb_arch_exit(void)485 void kgdb_arch_exit(void)
486 {
487 __debugger_ipi = old__debugger_ipi;
488 __debugger = old__debugger;
489 __debugger_bpt = old__debugger_bpt;
490 __debugger_sstep = old__debugger_sstep;
491 __debugger_iabr_match = old__debugger_iabr_match;
492 __debugger_break_match = old__debugger_break_match;
493 __debugger_fault_handler = old__debugger_fault_handler;
494 }
495