kgdb.c 15 KB

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  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. #include <linux/kernel.h>
  17. #include <linux/kgdb.h>
  18. #include <linux/smp.h>
  19. #include <linux/signal.h>
  20. #include <linux/ptrace.h>
  21. #include <linux/kdebug.h>
  22. #include <asm/current.h>
  23. #include <asm/processor.h>
  24. #include <asm/machdep.h>
  25. #include <asm/debug.h>
  26. #include <asm/code-patching.h>
  27. #include <linux/slab.h>
  28. #include <asm/inst.h>
  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_PPC_8xx)
  71. { 0x1000, 0x04 /* SIGILL */ }, /* software emulation */
  72. #else /* ! CONFIG_PPC_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. static int computeSignal(unsigned int tt)
  93. {
  94. struct hard_trap_info *ht;
  95. for (ht = hard_trap_info; ht->tt && ht->signo; ht++)
  96. if (ht->tt == tt)
  97. return ht->signo;
  98. return SIGHUP; /* default for things we don't know about */
  99. }
  100. /**
  101. *
  102. * kgdb_skipexception - Bail out of KGDB when we've been triggered.
  103. * @exception: Exception vector number
  104. * @regs: Current &struct pt_regs.
  105. *
  106. * On some architectures we need to skip a breakpoint exception when
  107. * it occurs after a breakpoint has been removed.
  108. *
  109. */
  110. int kgdb_skipexception(int exception, struct pt_regs *regs)
  111. {
  112. return kgdb_isremovedbreak(regs->nip);
  113. }
  114. static int kgdb_debugger_ipi(struct pt_regs *regs)
  115. {
  116. kgdb_nmicallback(raw_smp_processor_id(), regs);
  117. return 0;
  118. }
  119. #ifdef CONFIG_SMP
  120. void kgdb_roundup_cpus(void)
  121. {
  122. smp_send_debugger_break();
  123. }
  124. #endif
  125. /* KGDB functions to use existing PowerPC64 hooks. */
  126. static int kgdb_debugger(struct pt_regs *regs)
  127. {
  128. return !kgdb_handle_exception(1, computeSignal(TRAP(regs)),
  129. DIE_OOPS, regs);
  130. }
  131. static int kgdb_handle_breakpoint(struct pt_regs *regs)
  132. {
  133. if (user_mode(regs))
  134. return 0;
  135. if (kgdb_handle_exception(1, SIGTRAP, 0, regs) != 0)
  136. return 0;
  137. if (*(u32 *)regs->nip == BREAK_INSTR)
  138. regs->nip += BREAK_INSTR_SIZE;
  139. return 1;
  140. }
  141. static int kgdb_singlestep(struct pt_regs *regs)
  142. {
  143. if (user_mode(regs))
  144. return 0;
  145. kgdb_handle_exception(0, SIGTRAP, 0, regs);
  146. return 1;
  147. }
  148. static int kgdb_iabr_match(struct pt_regs *regs)
  149. {
  150. if (user_mode(regs))
  151. return 0;
  152. if (kgdb_handle_exception(0, computeSignal(TRAP(regs)), 0, regs) != 0)
  153. return 0;
  154. return 1;
  155. }
  156. static int kgdb_break_match(struct pt_regs *regs)
  157. {
  158. if (user_mode(regs))
  159. return 0;
  160. if (kgdb_handle_exception(0, computeSignal(TRAP(regs)), 0, regs) != 0)
  161. return 0;
  162. return 1;
  163. }
  164. #define PACK64(ptr, src) do { *(ptr++) = (src); } while (0)
  165. #define PACK32(ptr, src) do { \
  166. u32 *ptr32; \
  167. ptr32 = (u32 *)ptr; \
  168. *(ptr32++) = (src); \
  169. ptr = (unsigned long *)ptr32; \
  170. } while (0)
  171. void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p)
  172. {
  173. struct pt_regs *regs = (struct pt_regs *)(p->thread.ksp +
  174. STACK_FRAME_OVERHEAD);
  175. unsigned long *ptr = gdb_regs;
  176. int reg;
  177. memset(gdb_regs, 0, NUMREGBYTES);
  178. /* Regs GPR0-2 */
  179. for (reg = 0; reg < 3; reg++)
  180. PACK64(ptr, regs->gpr[reg]);
  181. /* Regs GPR3-13 are caller saved, not in regs->gpr[] */
  182. ptr += 11;
  183. /* Regs GPR14-31 */
  184. for (reg = 14; reg < 32; reg++)
  185. PACK64(ptr, regs->gpr[reg]);
  186. #ifdef CONFIG_FSL_BOOKE
  187. #ifdef CONFIG_SPE
  188. for (reg = 0; reg < 32; reg++)
  189. PACK64(ptr, p->thread.evr[reg]);
  190. #else
  191. ptr += 32;
  192. #endif
  193. #else
  194. /* fp registers not used by kernel, leave zero */
  195. ptr += 32 * 8 / sizeof(long);
  196. #endif
  197. PACK64(ptr, regs->nip);
  198. PACK64(ptr, regs->msr);
  199. PACK32(ptr, regs->ccr);
  200. PACK64(ptr, regs->link);
  201. PACK64(ptr, regs->ctr);
  202. PACK32(ptr, regs->xer);
  203. BUG_ON((unsigned long)ptr >
  204. (unsigned long)(((void *)gdb_regs) + NUMREGBYTES));
  205. }
  206. #define GDB_SIZEOF_REG sizeof(unsigned long)
  207. #define GDB_SIZEOF_REG_U32 sizeof(u32)
  208. #ifdef CONFIG_FSL_BOOKE
  209. #define GDB_SIZEOF_FLOAT_REG sizeof(unsigned long)
  210. #else
  211. #define GDB_SIZEOF_FLOAT_REG sizeof(u64)
  212. #endif
  213. struct dbg_reg_def_t dbg_reg_def[DBG_MAX_REG_NUM] =
  214. {
  215. { "r0", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[0]) },
  216. { "r1", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[1]) },
  217. { "r2", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[2]) },
  218. { "r3", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[3]) },
  219. { "r4", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[4]) },
  220. { "r5", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[5]) },
  221. { "r6", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[6]) },
  222. { "r7", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[7]) },
  223. { "r8", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[8]) },
  224. { "r9", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[9]) },
  225. { "r10", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[10]) },
  226. { "r11", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[11]) },
  227. { "r12", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[12]) },
  228. { "r13", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[13]) },
  229. { "r14", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[14]) },
  230. { "r15", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[15]) },
  231. { "r16", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[16]) },
  232. { "r17", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[17]) },
  233. { "r18", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[18]) },
  234. { "r19", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[19]) },
  235. { "r20", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[20]) },
  236. { "r21", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[21]) },
  237. { "r22", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[22]) },
  238. { "r23", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[23]) },
  239. { "r24", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[24]) },
  240. { "r25", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[25]) },
  241. { "r26", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[26]) },
  242. { "r27", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[27]) },
  243. { "r28", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[28]) },
  244. { "r29", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[29]) },
  245. { "r30", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[30]) },
  246. { "r31", GDB_SIZEOF_REG, offsetof(struct pt_regs, gpr[31]) },
  247. { "f0", GDB_SIZEOF_FLOAT_REG, 0 },
  248. { "f1", GDB_SIZEOF_FLOAT_REG, 1 },
  249. { "f2", GDB_SIZEOF_FLOAT_REG, 2 },
  250. { "f3", GDB_SIZEOF_FLOAT_REG, 3 },
  251. { "f4", GDB_SIZEOF_FLOAT_REG, 4 },
  252. { "f5", GDB_SIZEOF_FLOAT_REG, 5 },
  253. { "f6", GDB_SIZEOF_FLOAT_REG, 6 },
  254. { "f7", GDB_SIZEOF_FLOAT_REG, 7 },
  255. { "f8", GDB_SIZEOF_FLOAT_REG, 8 },
  256. { "f9", GDB_SIZEOF_FLOAT_REG, 9 },
  257. { "f10", GDB_SIZEOF_FLOAT_REG, 10 },
  258. { "f11", GDB_SIZEOF_FLOAT_REG, 11 },
  259. { "f12", GDB_SIZEOF_FLOAT_REG, 12 },
  260. { "f13", GDB_SIZEOF_FLOAT_REG, 13 },
  261. { "f14", GDB_SIZEOF_FLOAT_REG, 14 },
  262. { "f15", GDB_SIZEOF_FLOAT_REG, 15 },
  263. { "f16", GDB_SIZEOF_FLOAT_REG, 16 },
  264. { "f17", GDB_SIZEOF_FLOAT_REG, 17 },
  265. { "f18", GDB_SIZEOF_FLOAT_REG, 18 },
  266. { "f19", GDB_SIZEOF_FLOAT_REG, 19 },
  267. { "f20", GDB_SIZEOF_FLOAT_REG, 20 },
  268. { "f21", GDB_SIZEOF_FLOAT_REG, 21 },
  269. { "f22", GDB_SIZEOF_FLOAT_REG, 22 },
  270. { "f23", GDB_SIZEOF_FLOAT_REG, 23 },
  271. { "f24", GDB_SIZEOF_FLOAT_REG, 24 },
  272. { "f25", GDB_SIZEOF_FLOAT_REG, 25 },
  273. { "f26", GDB_SIZEOF_FLOAT_REG, 26 },
  274. { "f27", GDB_SIZEOF_FLOAT_REG, 27 },
  275. { "f28", GDB_SIZEOF_FLOAT_REG, 28 },
  276. { "f29", GDB_SIZEOF_FLOAT_REG, 29 },
  277. { "f30", GDB_SIZEOF_FLOAT_REG, 30 },
  278. { "f31", GDB_SIZEOF_FLOAT_REG, 31 },
  279. { "pc", GDB_SIZEOF_REG, offsetof(struct pt_regs, nip) },
  280. { "msr", GDB_SIZEOF_REG, offsetof(struct pt_regs, msr) },
  281. { "cr", GDB_SIZEOF_REG_U32, offsetof(struct pt_regs, ccr) },
  282. { "lr", GDB_SIZEOF_REG, offsetof(struct pt_regs, link) },
  283. { "ctr", GDB_SIZEOF_REG_U32, offsetof(struct pt_regs, ctr) },
  284. { "xer", GDB_SIZEOF_REG, offsetof(struct pt_regs, xer) },
  285. };
  286. char *dbg_get_reg(int regno, void *mem, struct pt_regs *regs)
  287. {
  288. if (regno >= DBG_MAX_REG_NUM || regno < 0)
  289. return NULL;
  290. if (regno < 32 || regno >= 64)
  291. /* First 0 -> 31 gpr registers*/
  292. /* pc, msr, ls... registers 64 -> 69 */
  293. memcpy(mem, (void *)regs + dbg_reg_def[regno].offset,
  294. dbg_reg_def[regno].size);
  295. if (regno >= 32 && regno < 64) {
  296. /* FP registers 32 -> 63 */
  297. #if defined(CONFIG_FSL_BOOKE) && defined(CONFIG_SPE)
  298. if (current)
  299. memcpy(mem, &current->thread.evr[regno-32],
  300. dbg_reg_def[regno].size);
  301. #else
  302. /* fp registers not used by kernel, leave zero */
  303. memset(mem, 0, dbg_reg_def[regno].size);
  304. #endif
  305. }
  306. return dbg_reg_def[regno].name;
  307. }
  308. int dbg_set_reg(int regno, void *mem, struct pt_regs *regs)
  309. {
  310. if (regno >= DBG_MAX_REG_NUM || regno < 0)
  311. return -EINVAL;
  312. if (regno < 32 || regno >= 64)
  313. /* First 0 -> 31 gpr registers*/
  314. /* pc, msr, ls... registers 64 -> 69 */
  315. memcpy((void *)regs + dbg_reg_def[regno].offset, mem,
  316. dbg_reg_def[regno].size);
  317. if (regno >= 32 && regno < 64) {
  318. /* FP registers 32 -> 63 */
  319. #if defined(CONFIG_FSL_BOOKE) && defined(CONFIG_SPE)
  320. memcpy(&current->thread.evr[regno-32], mem,
  321. dbg_reg_def[regno].size);
  322. #else
  323. /* fp registers not used by kernel, leave zero */
  324. return 0;
  325. #endif
  326. }
  327. return 0;
  328. }
  329. void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long pc)
  330. {
  331. regs->nip = pc;
  332. }
  333. /*
  334. * This function does PowerPC specific procesing for interfacing to gdb.
  335. */
  336. int kgdb_arch_handle_exception(int vector, int signo, int err_code,
  337. char *remcom_in_buffer, char *remcom_out_buffer,
  338. struct pt_regs *linux_regs)
  339. {
  340. char *ptr = &remcom_in_buffer[1];
  341. unsigned long addr;
  342. switch (remcom_in_buffer[0]) {
  343. /*
  344. * sAA..AA Step one instruction from AA..AA
  345. * This will return an error to gdb ..
  346. */
  347. case 's':
  348. case 'c':
  349. /* handle the optional parameter */
  350. if (kgdb_hex2long(&ptr, &addr))
  351. linux_regs->nip = addr;
  352. atomic_set(&kgdb_cpu_doing_single_step, -1);
  353. /* set the trace bit if we're stepping */
  354. if (remcom_in_buffer[0] == 's') {
  355. #ifdef CONFIG_PPC_ADV_DEBUG_REGS
  356. mtspr(SPRN_DBCR0,
  357. mfspr(SPRN_DBCR0) | DBCR0_IC | DBCR0_IDM);
  358. linux_regs->msr |= MSR_DE;
  359. #else
  360. linux_regs->msr |= MSR_SE;
  361. #endif
  362. atomic_set(&kgdb_cpu_doing_single_step,
  363. raw_smp_processor_id());
  364. }
  365. return 0;
  366. }
  367. return -1;
  368. }
  369. int kgdb_arch_set_breakpoint(struct kgdb_bkpt *bpt)
  370. {
  371. int err;
  372. unsigned int instr;
  373. struct ppc_inst *addr = (struct ppc_inst *)bpt->bpt_addr;
  374. err = get_kernel_nofault(instr, (unsigned *) addr);
  375. if (err)
  376. return err;
  377. err = patch_instruction(addr, ppc_inst(BREAK_INSTR));
  378. if (err)
  379. return -EFAULT;
  380. *(unsigned int *)bpt->saved_instr = instr;
  381. return 0;
  382. }
  383. int kgdb_arch_remove_breakpoint(struct kgdb_bkpt *bpt)
  384. {
  385. int err;
  386. unsigned int instr = *(unsigned int *)bpt->saved_instr;
  387. struct ppc_inst *addr = (struct ppc_inst *)bpt->bpt_addr;
  388. err = patch_instruction(addr, ppc_inst(instr));
  389. if (err)
  390. return -EFAULT;
  391. return 0;
  392. }
  393. /*
  394. * Global data
  395. */
  396. const struct kgdb_arch arch_kgdb_ops;
  397. static int kgdb_not_implemented(struct pt_regs *regs)
  398. {
  399. return 0;
  400. }
  401. static void *old__debugger_ipi;
  402. static void *old__debugger;
  403. static void *old__debugger_bpt;
  404. static void *old__debugger_sstep;
  405. static void *old__debugger_iabr_match;
  406. static void *old__debugger_break_match;
  407. static void *old__debugger_fault_handler;
  408. int kgdb_arch_init(void)
  409. {
  410. old__debugger_ipi = __debugger_ipi;
  411. old__debugger = __debugger;
  412. old__debugger_bpt = __debugger_bpt;
  413. old__debugger_sstep = __debugger_sstep;
  414. old__debugger_iabr_match = __debugger_iabr_match;
  415. old__debugger_break_match = __debugger_break_match;
  416. old__debugger_fault_handler = __debugger_fault_handler;
  417. __debugger_ipi = kgdb_debugger_ipi;
  418. __debugger = kgdb_debugger;
  419. __debugger_bpt = kgdb_handle_breakpoint;
  420. __debugger_sstep = kgdb_singlestep;
  421. __debugger_iabr_match = kgdb_iabr_match;
  422. __debugger_break_match = kgdb_break_match;
  423. __debugger_fault_handler = kgdb_not_implemented;
  424. return 0;
  425. }
  426. void kgdb_arch_exit(void)
  427. {
  428. __debugger_ipi = old__debugger_ipi;
  429. __debugger = old__debugger;
  430. __debugger_bpt = old__debugger_bpt;
  431. __debugger_sstep = old__debugger_sstep;
  432. __debugger_iabr_match = old__debugger_iabr_match;
  433. __debugger_break_match = old__debugger_break_match;
  434. __debugger_fault_handler = old__debugger_fault_handler;
  435. }