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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * PowerPC backend to the KGDB stub.
4 *
5 * 1998 (c) Michael AK Tesch ([email protected])
6 * Copyright (C) 2003 Timesys Corporation.
7 * Copyright (C) 2004-2006 MontaVista Software, Inc.
8 * PPC64 Mods (C) 2005 Frank Rowand ([email protected])
9 * PPC32 support restored by Vitaly Wool <[email protected]> and
10 * Sergei Shtylyov <[email protected]>
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/text-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 */
33static 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
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 */
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
92static 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 * kgdb_skipexception - Bail out of KGDB when we've been triggered.
105 * @exception: Exception vector number
106 * @regs: Current &struct pt_regs.
107 *
108 * On some architectures we need to skip a breakpoint exception when
109 * it occurs after a breakpoint has been removed.
110 *
111 * Return: return %1 if the breakpoint for this address has been removed,
112 * otherwise return %0
113 */
114int kgdb_skipexception(int exception, struct pt_regs *regs)
115{
116 return kgdb_isremovedbreak(regs->nip);
117}
118
119static int kgdb_debugger_ipi(struct pt_regs *regs)
120{
121 kgdb_nmicallback(raw_smp_processor_id(), regs);
122 return 0;
123}
124
125#ifdef CONFIG_SMP
126void kgdb_roundup_cpus(void)
127{
128 smp_send_debugger_break();
129}
130#endif
131
132/* KGDB functions to use existing PowerPC64 hooks. */
133static int kgdb_debugger(struct pt_regs *regs)
134{
135 return !kgdb_handle_exception(1, computeSignal(TRAP(regs)),
136 DIE_OOPS, regs);
137}
138
139static int kgdb_handle_breakpoint(struct pt_regs *regs)
140{
141 if (user_mode(regs))
142 return 0;
143
144 if (kgdb_handle_exception(1, SIGTRAP, 0, regs) != 0)
145 return 0;
146
147 if (*(u32 *)regs->nip == BREAK_INSTR)
148 regs_add_return_ip(regs, BREAK_INSTR_SIZE);
149
150 return 1;
151}
152
153static int kgdb_singlestep(struct pt_regs *regs)
154{
155 if (user_mode(regs))
156 return 0;
157
158 kgdb_handle_exception(0, SIGTRAP, 0, regs);
159
160 return 1;
161}
162
163static int kgdb_iabr_match(struct pt_regs *regs)
164{
165 if (user_mode(regs))
166 return 0;
167
168 if (kgdb_handle_exception(0, computeSignal(TRAP(regs)), 0, regs) != 0)
169 return 0;
170 return 1;
171}
172
173static int kgdb_break_match(struct pt_regs *regs)
174{
175 if (user_mode(regs))
176 return 0;
177
178 if (kgdb_handle_exception(0, computeSignal(TRAP(regs)), 0, regs) != 0)
179 return 0;
180 return 1;
181}
182
183#define PACK64(ptr, src) do { *(ptr++) = (src); } while (0)
184
185#define PACK32(ptr, src) do { \
186 u32 *ptr32; \
187 ptr32 = (u32 *)ptr; \
188 *(ptr32++) = (src); \
189 ptr = (unsigned long *)ptr32; \
190 } while (0)
191
192void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p)
193{
194 struct pt_regs *regs = (struct pt_regs *)(p->thread.ksp +
195 STACK_INT_FRAME_REGS);
196 unsigned long *ptr = gdb_regs;
197 int reg;
198
199 memset(gdb_regs, 0, NUMREGBYTES);
200
201 /* Regs GPR0-2 */
202 for (reg = 0; reg < 3; reg++)
203 PACK64(ptr, regs->gpr[reg]);
204
205 /* Regs GPR3-13 are caller saved, not in regs->gpr[] */
206 ptr += 11;
207
208 /* Regs GPR14-31 */
209 for (reg = 14; reg < 32; reg++)
210 PACK64(ptr, regs->gpr[reg]);
211
212#ifdef CONFIG_PPC_85xx
213#ifdef CONFIG_SPE
214 for (reg = 0; reg < 32; reg++)
215 PACK64(ptr, p->thread.evr[reg]);
216#else
217 ptr += 32;
218#endif
219#else
220 /* fp registers not used by kernel, leave zero */
221 ptr += 32 * 8 / sizeof(long);
222#endif
223
224 PACK64(ptr, regs->nip);
225 PACK64(ptr, regs->msr);
226 PACK32(ptr, regs->ccr);
227 PACK64(ptr, regs->link);
228 PACK64(ptr, regs->ctr);
229 PACK32(ptr, regs->xer);
230
231 BUG_ON((unsigned long)ptr >
232 (unsigned long)(((void *)gdb_regs) + NUMREGBYTES));
233}
234
235#define GDB_SIZEOF_REG sizeof(unsigned long)
236#define GDB_SIZEOF_REG_U32 sizeof(u32)
237
238#ifdef CONFIG_PPC_85xx
239#define GDB_SIZEOF_FLOAT_REG sizeof(unsigned long)
240#else
241#define GDB_SIZEOF_FLOAT_REG sizeof(u64)
242#endif
243
244struct dbg_reg_def_t dbg_reg_def[DBG_MAX_REG_NUM] =
245{
246 { "r0", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[0]) },
247 { "r1", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[1]) },
248 { "r2", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[2]) },
249 { "r3", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[3]) },
250 { "r4", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[4]) },
251 { "r5", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[5]) },
252 { "r6", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[6]) },
253 { "r7", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[7]) },
254 { "r8", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[8]) },
255 { "r9", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[9]) },
256 { "r10", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[10]) },
257 { "r11", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[11]) },
258 { "r12", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[12]) },
259 { "r13", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[13]) },
260 { "r14", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[14]) },
261 { "r15", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[15]) },
262 { "r16", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[16]) },
263 { "r17", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[17]) },
264 { "r18", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[18]) },
265 { "r19", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[19]) },
266 { "r20", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[20]) },
267 { "r21", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[21]) },
268 { "r22", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[22]) },
269 { "r23", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[23]) },
270 { "r24", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[24]) },
271 { "r25", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[25]) },
272 { "r26", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[26]) },
273 { "r27", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[27]) },
274 { "r28", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[28]) },
275 { "r29", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[29]) },
276 { "r30", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[30]) },
277 { "r31", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[31]) },
278
279 { "f0", GDB_SIZEOF_FLOAT_REG, 0 },
280 { "f1", GDB_SIZEOF_FLOAT_REG, 1 },
281 { "f2", GDB_SIZEOF_FLOAT_REG, 2 },
282 { "f3", GDB_SIZEOF_FLOAT_REG, 3 },
283 { "f4", GDB_SIZEOF_FLOAT_REG, 4 },
284 { "f5", GDB_SIZEOF_FLOAT_REG, 5 },
285 { "f6", GDB_SIZEOF_FLOAT_REG, 6 },
286 { "f7", GDB_SIZEOF_FLOAT_REG, 7 },
287 { "f8", GDB_SIZEOF_FLOAT_REG, 8 },
288 { "f9", GDB_SIZEOF_FLOAT_REG, 9 },
289 { "f10", GDB_SIZEOF_FLOAT_REG, 10 },
290 { "f11", GDB_SIZEOF_FLOAT_REG, 11 },
291 { "f12", GDB_SIZEOF_FLOAT_REG, 12 },
292 { "f13", GDB_SIZEOF_FLOAT_REG, 13 },
293 { "f14", GDB_SIZEOF_FLOAT_REG, 14 },
294 { "f15", GDB_SIZEOF_FLOAT_REG, 15 },
295 { "f16", GDB_SIZEOF_FLOAT_REG, 16 },
296 { "f17", GDB_SIZEOF_FLOAT_REG, 17 },
297 { "f18", GDB_SIZEOF_FLOAT_REG, 18 },
298 { "f19", GDB_SIZEOF_FLOAT_REG, 19 },
299 { "f20", GDB_SIZEOF_FLOAT_REG, 20 },
300 { "f21", GDB_SIZEOF_FLOAT_REG, 21 },
301 { "f22", GDB_SIZEOF_FLOAT_REG, 22 },
302 { "f23", GDB_SIZEOF_FLOAT_REG, 23 },
303 { "f24", GDB_SIZEOF_FLOAT_REG, 24 },
304 { "f25", GDB_SIZEOF_FLOAT_REG, 25 },
305 { "f26", GDB_SIZEOF_FLOAT_REG, 26 },
306 { "f27", GDB_SIZEOF_FLOAT_REG, 27 },
307 { "f28", GDB_SIZEOF_FLOAT_REG, 28 },
308 { "f29", GDB_SIZEOF_FLOAT_REG, 29 },
309 { "f30", GDB_SIZEOF_FLOAT_REG, 30 },
310 { "f31", GDB_SIZEOF_FLOAT_REG, 31 },
311
312 { "pc", GDB_SIZEOF_REG, offsetof(struct pt_regs, nip) },
313 { "msr", GDB_SIZEOF_REG, offsetof(struct pt_regs, msr) },
314 { "cr", GDB_SIZEOF_REG_U32, offsetof(struct pt_regs, ccr) },
315 { "lr", GDB_SIZEOF_REG, offsetof(struct pt_regs, link) },
316 { "ctr", GDB_SIZEOF_REG_U32, offsetof(struct pt_regs, ctr) },
317 { "xer", GDB_SIZEOF_REG, offsetof(struct pt_regs, xer) },
318};
319
320char *dbg_get_reg(int regno, void *mem, struct pt_regs *regs)
321{
322 if (regno >= DBG_MAX_REG_NUM || regno < 0)
323 return NULL;
324
325 if (regno < 32 || regno >= 64)
326 /* First 0 -> 31 gpr registers*/
327 /* pc, msr, ls... registers 64 -> 69 */
328 memcpy(mem, (void *)regs + dbg_reg_def[regno].offset,
329 dbg_reg_def[regno].size);
330
331 if (regno >= 32 && regno < 64) {
332 /* FP registers 32 -> 63 */
333#if defined(CONFIG_PPC_85xx) && defined(CONFIG_SPE)
334 if (current)
335 memcpy(mem, &current->thread.evr[regno-32],
336 dbg_reg_def[regno].size);
337#else
338 /* fp registers not used by kernel, leave zero */
339 memset(mem, 0, dbg_reg_def[regno].size);
340#endif
341 }
342
343 return dbg_reg_def[regno].name;
344}
345
346int dbg_set_reg(int regno, void *mem, struct pt_regs *regs)
347{
348 if (regno >= DBG_MAX_REG_NUM || regno < 0)
349 return -EINVAL;
350
351 if (regno < 32 || regno >= 64)
352 /* First 0 -> 31 gpr registers*/
353 /* pc, msr, ls... registers 64 -> 69 */
354 memcpy((void *)regs + dbg_reg_def[regno].offset, mem,
355 dbg_reg_def[regno].size);
356
357 if (regno >= 32 && regno < 64) {
358 /* FP registers 32 -> 63 */
359#if defined(CONFIG_PPC_85xx) && defined(CONFIG_SPE)
360 memcpy(&current->thread.evr[regno-32], mem,
361 dbg_reg_def[regno].size);
362#else
363 /* fp registers not used by kernel, leave zero */
364 return 0;
365#endif
366 }
367
368 return 0;
369}
370
371void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long pc)
372{
373 regs_set_return_ip(regs, pc);
374}
375
376/*
377 * This function does PowerPC specific processing for interfacing to gdb.
378 */
379int kgdb_arch_handle_exception(int vector, int signo, int err_code,
380 char *remcom_in_buffer, char *remcom_out_buffer,
381 struct pt_regs *linux_regs)
382{
383 char *ptr = &remcom_in_buffer[1];
384 unsigned long addr;
385
386 switch (remcom_in_buffer[0]) {
387 /*
388 * sAA..AA Step one instruction from AA..AA
389 * This will return an error to gdb ..
390 */
391 case 's':
392 case 'c':
393 /* handle the optional parameter */
394 if (kgdb_hex2long(&ptr, &addr))
395 regs_set_return_ip(linux_regs, addr);
396
397 atomic_set(&kgdb_cpu_doing_single_step, -1);
398 /* set the trace bit if we're stepping */
399 if (remcom_in_buffer[0] == 's') {
400#ifdef CONFIG_PPC_ADV_DEBUG_REGS
401 mtspr(SPRN_DBCR0,
402 mfspr(SPRN_DBCR0) | DBCR0_IC | DBCR0_IDM);
403 regs_set_return_msr(linux_regs, linux_regs->msr | MSR_DE);
404#else
405 regs_set_return_msr(linux_regs, linux_regs->msr | MSR_SE);
406#endif
407 atomic_set(&kgdb_cpu_doing_single_step,
408 raw_smp_processor_id());
409 }
410 return 0;
411 }
412
413 return -1;
414}
415
416int kgdb_arch_set_breakpoint(struct kgdb_bkpt *bpt)
417{
418 u32 instr, *addr = (u32 *)bpt->bpt_addr;
419 int err;
420
421 err = get_kernel_nofault(instr, addr);
422 if (err)
423 return err;
424
425 err = patch_instruction(addr, ppc_inst(BREAK_INSTR));
426 if (err)
427 return -EFAULT;
428
429 *(u32 *)bpt->saved_instr = instr;
430
431 return 0;
432}
433
434int kgdb_arch_remove_breakpoint(struct kgdb_bkpt *bpt)
435{
436 int err;
437 unsigned int instr = *(unsigned int *)bpt->saved_instr;
438 u32 *addr = (u32 *)bpt->bpt_addr;
439
440 err = patch_instruction(addr, ppc_inst(instr));
441 if (err)
442 return -EFAULT;
443
444 return 0;
445}
446
447/*
448 * Global data
449 */
450const struct kgdb_arch arch_kgdb_ops;
451
452static int kgdb_not_implemented(struct pt_regs *regs)
453{
454 return 0;
455}
456
457static void *old__debugger_ipi;
458static void *old__debugger;
459static void *old__debugger_bpt;
460static void *old__debugger_sstep;
461static void *old__debugger_iabr_match;
462static void *old__debugger_break_match;
463static void *old__debugger_fault_handler;
464
465int kgdb_arch_init(void)
466{
467 old__debugger_ipi = __debugger_ipi;
468 old__debugger = __debugger;
469 old__debugger_bpt = __debugger_bpt;
470 old__debugger_sstep = __debugger_sstep;
471 old__debugger_iabr_match = __debugger_iabr_match;
472 old__debugger_break_match = __debugger_break_match;
473 old__debugger_fault_handler = __debugger_fault_handler;
474
475 __debugger_ipi = kgdb_debugger_ipi;
476 __debugger = kgdb_debugger;
477 __debugger_bpt = kgdb_handle_breakpoint;
478 __debugger_sstep = kgdb_singlestep;
479 __debugger_iabr_match = kgdb_iabr_match;
480 __debugger_break_match = kgdb_break_match;
481 __debugger_fault_handler = kgdb_not_implemented;
482
483 return 0;
484}
485
486void kgdb_arch_exit(void)
487{
488 __debugger_ipi = old__debugger_ipi;
489 __debugger = old__debugger;
490 __debugger_bpt = old__debugger_bpt;
491 __debugger_sstep = old__debugger_sstep;
492 __debugger_iabr_match = old__debugger_iabr_match;
493 __debugger_break_match = old__debugger_break_match;
494 __debugger_fault_handler = old__debugger_fault_handler;
495}