process.c 14 KB

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  1. /*
  2. * This file is subject to the terms and conditions of the GNU General Public
  3. * License. See the file "COPYING" in the main directory of this archive
  4. * for more details.
  5. *
  6. * Copyright (C) 1994 - 1999, 2000 by Ralf Baechle and others.
  7. * Copyright (C) 2005, 2006 by Ralf Baechle (ralf@linux-mips.org)
  8. * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
  9. * Copyright (C) 2004 Thiemo Seufer
  10. * Copyright (C) 2013 Imagination Technologies Ltd.
  11. */
  12. #include <linux/errno.h>
  13. #include <linux/sched.h>
  14. #include <linux/tick.h>
  15. #include <linux/kernel.h>
  16. #include <linux/mm.h>
  17. #include <linux/stddef.h>
  18. #include <linux/unistd.h>
  19. #include <linux/export.h>
  20. #include <linux/ptrace.h>
  21. #include <linux/mman.h>
  22. #include <linux/personality.h>
  23. #include <linux/sys.h>
  24. #include <linux/user.h>
  25. #include <linux/init.h>
  26. #include <linux/completion.h>
  27. #include <linux/kallsyms.h>
  28. #include <linux/random.h>
  29. #include <asm/asm.h>
  30. #include <asm/bootinfo.h>
  31. #include <asm/cpu.h>
  32. #include <asm/dsp.h>
  33. #include <asm/fpu.h>
  34. #include <asm/pgtable.h>
  35. #include <asm/mipsregs.h>
  36. #include <asm/processor.h>
  37. #include <asm/uaccess.h>
  38. #include <asm/io.h>
  39. #include <asm/elf.h>
  40. #include <asm/isadep.h>
  41. #include <asm/inst.h>
  42. #include <asm/stacktrace.h>
  43. #ifdef CONFIG_HOTPLUG_CPU
  44. void arch_cpu_idle_dead(void)
  45. {
  46. /* What the heck is this check doing ? */
  47. if (!cpu_isset(smp_processor_id(), cpu_callin_map))
  48. play_dead();
  49. }
  50. #endif
  51. asmlinkage void ret_from_fork(void);
  52. asmlinkage void ret_from_kernel_thread(void);
  53. void start_thread(struct pt_regs * regs, unsigned long pc, unsigned long sp)
  54. {
  55. unsigned long status;
  56. /* New thread loses kernel privileges. */
  57. status = regs->cp0_status & ~(ST0_CU0|ST0_CU1|ST0_FR|KU_MASK);
  58. #ifdef CONFIG_64BIT
  59. status |= test_thread_flag(TIF_32BIT_REGS) ? 0 : ST0_FR;
  60. #endif
  61. status |= KU_USER;
  62. regs->cp0_status = status;
  63. clear_used_math();
  64. clear_fpu_owner();
  65. if (cpu_has_dsp)
  66. __init_dsp();
  67. regs->cp0_epc = pc;
  68. regs->regs[29] = sp;
  69. }
  70. void exit_thread(void)
  71. {
  72. }
  73. void flush_thread(void)
  74. {
  75. }
  76. int copy_thread(unsigned long clone_flags, unsigned long usp,
  77. unsigned long arg, struct task_struct *p)
  78. {
  79. struct thread_info *ti = task_thread_info(p);
  80. struct pt_regs *childregs, *regs = current_pt_regs();
  81. unsigned long childksp;
  82. p->set_child_tid = p->clear_child_tid = NULL;
  83. childksp = (unsigned long)task_stack_page(p) + THREAD_SIZE - 32;
  84. preempt_disable();
  85. if (is_fpu_owner())
  86. save_fp(p);
  87. if (cpu_has_dsp)
  88. save_dsp(p);
  89. preempt_enable();
  90. /* set up new TSS. */
  91. childregs = (struct pt_regs *) childksp - 1;
  92. /* Put the stack after the struct pt_regs. */
  93. childksp = (unsigned long) childregs;
  94. p->thread.cp0_status = read_c0_status() & ~(ST0_CU2|ST0_CU1);
  95. if (unlikely(p->flags & PF_KTHREAD)) {
  96. unsigned long status = p->thread.cp0_status;
  97. memset(childregs, 0, sizeof(struct pt_regs));
  98. ti->addr_limit = KERNEL_DS;
  99. p->thread.reg16 = usp; /* fn */
  100. p->thread.reg17 = arg;
  101. p->thread.reg29 = childksp;
  102. p->thread.reg31 = (unsigned long) ret_from_kernel_thread;
  103. #if defined(CONFIG_CPU_R3000) || defined(CONFIG_CPU_TX39XX)
  104. status = (status & ~(ST0_KUP | ST0_IEP | ST0_IEC)) |
  105. ((status & (ST0_KUC | ST0_IEC)) << 2);
  106. #else
  107. status |= ST0_EXL;
  108. #endif
  109. childregs->cp0_status = status;
  110. return 0;
  111. }
  112. *childregs = *regs;
  113. childregs->regs[7] = 0; /* Clear error flag */
  114. childregs->regs[2] = 0; /* Child gets zero as return value */
  115. if (usp)
  116. childregs->regs[29] = usp;
  117. ti->addr_limit = USER_DS;
  118. p->thread.reg29 = (unsigned long) childregs;
  119. p->thread.reg31 = (unsigned long) ret_from_fork;
  120. /*
  121. * New tasks lose permission to use the fpu. This accelerates context
  122. * switching for most programs since they don't use the fpu.
  123. */
  124. childregs->cp0_status &= ~(ST0_CU2|ST0_CU1);
  125. #ifdef CONFIG_MIPS_MT_SMTC
  126. /*
  127. * SMTC restores TCStatus after Status, and the CU bits
  128. * are aliased there.
  129. */
  130. childregs->cp0_tcstatus &= ~(ST0_CU2|ST0_CU1);
  131. #endif
  132. clear_tsk_thread_flag(p, TIF_USEDFPU);
  133. #ifdef CONFIG_MIPS_MT_FPAFF
  134. clear_tsk_thread_flag(p, TIF_FPUBOUND);
  135. #endif /* CONFIG_MIPS_MT_FPAFF */
  136. if (clone_flags & CLONE_SETTLS)
  137. ti->tp_value = regs->regs[7];
  138. return 0;
  139. }
  140. /* Fill in the fpu structure for a core dump.. */
  141. int dump_fpu(struct pt_regs *regs, elf_fpregset_t *r)
  142. {
  143. memcpy(r, &current->thread.fpu, sizeof(current->thread.fpu));
  144. return 1;
  145. }
  146. void elf_dump_regs(elf_greg_t *gp, struct pt_regs *regs)
  147. {
  148. int i;
  149. for (i = 0; i < EF_R0; i++)
  150. gp[i] = 0;
  151. gp[EF_R0] = 0;
  152. for (i = 1; i <= 31; i++)
  153. gp[EF_R0 + i] = regs->regs[i];
  154. gp[EF_R26] = 0;
  155. gp[EF_R27] = 0;
  156. gp[EF_LO] = regs->lo;
  157. gp[EF_HI] = regs->hi;
  158. gp[EF_CP0_EPC] = regs->cp0_epc;
  159. gp[EF_CP0_BADVADDR] = regs->cp0_badvaddr;
  160. gp[EF_CP0_STATUS] = regs->cp0_status;
  161. gp[EF_CP0_CAUSE] = regs->cp0_cause;
  162. #ifdef EF_UNUSED0
  163. gp[EF_UNUSED0] = 0;
  164. #endif
  165. }
  166. int dump_task_regs(struct task_struct *tsk, elf_gregset_t *regs)
  167. {
  168. elf_dump_regs(*regs, task_pt_regs(tsk));
  169. return 1;
  170. }
  171. int dump_task_fpu(struct task_struct *t, elf_fpregset_t *fpr)
  172. {
  173. memcpy(fpr, &t->thread.fpu, sizeof(current->thread.fpu));
  174. return 1;
  175. }
  176. #ifdef CONFIG_CC_STACKPROTECTOR
  177. #include <linux/stackprotector.h>
  178. unsigned long __stack_chk_guard __read_mostly;
  179. EXPORT_SYMBOL(__stack_chk_guard);
  180. #endif
  181. struct mips_frame_info {
  182. void *func;
  183. unsigned long func_size;
  184. int frame_size;
  185. int pc_offset;
  186. };
  187. #define J_TARGET(pc,target) \
  188. (((unsigned long)(pc) & 0xf0000000) | ((target) << 2))
  189. static inline int is_ra_save_ins(union mips_instruction *ip)
  190. {
  191. #ifdef CONFIG_CPU_MICROMIPS
  192. union mips_instruction mmi;
  193. /*
  194. * swsp ra,offset
  195. * swm16 reglist,offset(sp)
  196. * swm32 reglist,offset(sp)
  197. * sw32 ra,offset(sp)
  198. * jradiussp - NOT SUPPORTED
  199. *
  200. * microMIPS is way more fun...
  201. */
  202. if (mm_insn_16bit(ip->halfword[0])) {
  203. mmi.word = (ip->halfword[0] << 16);
  204. return ((mmi.mm16_r5_format.opcode == mm_swsp16_op &&
  205. mmi.mm16_r5_format.rt == 31) ||
  206. (mmi.mm16_m_format.opcode == mm_pool16c_op &&
  207. mmi.mm16_m_format.func == mm_swm16_op));
  208. }
  209. else {
  210. mmi.halfword[0] = ip->halfword[1];
  211. mmi.halfword[1] = ip->halfword[0];
  212. return ((mmi.mm_m_format.opcode == mm_pool32b_op &&
  213. mmi.mm_m_format.rd > 9 &&
  214. mmi.mm_m_format.base == 29 &&
  215. mmi.mm_m_format.func == mm_swm32_func) ||
  216. (mmi.i_format.opcode == mm_sw32_op &&
  217. mmi.i_format.rs == 29 &&
  218. mmi.i_format.rt == 31));
  219. }
  220. #else
  221. /* sw / sd $ra, offset($sp) */
  222. return (ip->i_format.opcode == sw_op || ip->i_format.opcode == sd_op) &&
  223. ip->i_format.rs == 29 &&
  224. ip->i_format.rt == 31;
  225. #endif
  226. }
  227. static inline int is_jump_ins(union mips_instruction *ip)
  228. {
  229. #ifdef CONFIG_CPU_MICROMIPS
  230. /*
  231. * jr16,jrc,jalr16,jalr16
  232. * jal
  233. * jalr/jr,jalr.hb/jr.hb,jalrs,jalrs.hb
  234. * jraddiusp - NOT SUPPORTED
  235. *
  236. * microMIPS is kind of more fun...
  237. */
  238. union mips_instruction mmi;
  239. mmi.word = (ip->halfword[0] << 16);
  240. if ((mmi.mm16_r5_format.opcode == mm_pool16c_op &&
  241. (mmi.mm16_r5_format.rt & mm_jr16_op) == mm_jr16_op) ||
  242. ip->j_format.opcode == mm_jal32_op)
  243. return 1;
  244. if (ip->r_format.opcode != mm_pool32a_op ||
  245. ip->r_format.func != mm_pool32axf_op)
  246. return 0;
  247. return (((ip->u_format.uimmediate >> 6) & mm_jalr_op) == mm_jalr_op);
  248. #else
  249. if (ip->j_format.opcode == j_op)
  250. return 1;
  251. if (ip->j_format.opcode == jal_op)
  252. return 1;
  253. if (ip->r_format.opcode != spec_op)
  254. return 0;
  255. return ip->r_format.func == jalr_op || ip->r_format.func == jr_op;
  256. #endif
  257. }
  258. static inline int is_sp_move_ins(union mips_instruction *ip)
  259. {
  260. #ifdef CONFIG_CPU_MICROMIPS
  261. /*
  262. * addiusp -imm
  263. * addius5 sp,-imm
  264. * addiu32 sp,sp,-imm
  265. * jradiussp - NOT SUPPORTED
  266. *
  267. * microMIPS is not more fun...
  268. */
  269. if (mm_insn_16bit(ip->halfword[0])) {
  270. union mips_instruction mmi;
  271. mmi.word = (ip->halfword[0] << 16);
  272. return ((mmi.mm16_r3_format.opcode == mm_pool16d_op &&
  273. mmi.mm16_r3_format.simmediate && mm_addiusp_func) ||
  274. (mmi.mm16_r5_format.opcode == mm_pool16d_op &&
  275. mmi.mm16_r5_format.rt == 29));
  276. }
  277. return (ip->mm_i_format.opcode == mm_addiu32_op &&
  278. ip->mm_i_format.rt == 29 && ip->mm_i_format.rs == 29);
  279. #else
  280. /* addiu/daddiu sp,sp,-imm */
  281. if (ip->i_format.rs != 29 || ip->i_format.rt != 29)
  282. return 0;
  283. if (ip->i_format.opcode == addiu_op || ip->i_format.opcode == daddiu_op)
  284. return 1;
  285. #endif
  286. return 0;
  287. }
  288. static int get_frame_info(struct mips_frame_info *info)
  289. {
  290. #ifdef CONFIG_CPU_MICROMIPS
  291. union mips_instruction *ip = (void *) (((char *) info->func) - 1);
  292. #else
  293. union mips_instruction *ip = info->func;
  294. #endif
  295. unsigned max_insns = info->func_size / sizeof(union mips_instruction);
  296. unsigned i;
  297. info->pc_offset = -1;
  298. info->frame_size = 0;
  299. if (!ip)
  300. goto err;
  301. if (max_insns == 0)
  302. max_insns = 128U; /* unknown function size */
  303. max_insns = min(128U, max_insns);
  304. for (i = 0; i < max_insns; i++, ip++) {
  305. if (is_jump_ins(ip))
  306. break;
  307. if (!info->frame_size) {
  308. if (is_sp_move_ins(ip))
  309. {
  310. #ifdef CONFIG_CPU_MICROMIPS
  311. if (mm_insn_16bit(ip->halfword[0]))
  312. {
  313. unsigned short tmp;
  314. if (ip->halfword[0] & mm_addiusp_func)
  315. {
  316. tmp = (((ip->halfword[0] >> 1) & 0x1ff) << 2);
  317. info->frame_size = -(signed short)(tmp | ((tmp & 0x100) ? 0xfe00 : 0));
  318. } else {
  319. tmp = (ip->halfword[0] >> 1);
  320. info->frame_size = -(signed short)(tmp & 0xf);
  321. }
  322. ip = (void *) &ip->halfword[1];
  323. ip--;
  324. } else
  325. #endif
  326. info->frame_size = - ip->i_format.simmediate;
  327. }
  328. continue;
  329. }
  330. if (info->pc_offset == -1 && is_ra_save_ins(ip)) {
  331. info->pc_offset =
  332. ip->i_format.simmediate / sizeof(long);
  333. break;
  334. }
  335. }
  336. if (info->frame_size && info->pc_offset >= 0) /* nested */
  337. return 0;
  338. if (info->pc_offset < 0) /* leaf */
  339. return 1;
  340. /* prologue seems boggus... */
  341. err:
  342. return -1;
  343. }
  344. static struct mips_frame_info schedule_mfi __read_mostly;
  345. #ifdef CONFIG_KALLSYMS
  346. static unsigned long get___schedule_addr(void)
  347. {
  348. return kallsyms_lookup_name("__schedule");
  349. }
  350. #else
  351. static unsigned long get___schedule_addr(void)
  352. {
  353. union mips_instruction *ip = (void *)schedule;
  354. int max_insns = 8;
  355. int i;
  356. for (i = 0; i < max_insns; i++, ip++) {
  357. if (ip->j_format.opcode == j_op)
  358. return J_TARGET(ip, ip->j_format.target);
  359. }
  360. return 0;
  361. }
  362. #endif
  363. static int __init frame_info_init(void)
  364. {
  365. unsigned long size = 0;
  366. #ifdef CONFIG_KALLSYMS
  367. unsigned long ofs;
  368. #endif
  369. unsigned long addr;
  370. addr = get___schedule_addr();
  371. if (!addr)
  372. addr = (unsigned long)schedule;
  373. #ifdef CONFIG_KALLSYMS
  374. kallsyms_lookup_size_offset(addr, &size, &ofs);
  375. #endif
  376. schedule_mfi.func = (void *)addr;
  377. schedule_mfi.func_size = size;
  378. get_frame_info(&schedule_mfi);
  379. /*
  380. * Without schedule() frame info, result given by
  381. * thread_saved_pc() and get_wchan() are not reliable.
  382. */
  383. if (schedule_mfi.pc_offset < 0)
  384. printk("Can't analyze schedule() prologue at %p\n", schedule);
  385. return 0;
  386. }
  387. arch_initcall(frame_info_init);
  388. /*
  389. * Return saved PC of a blocked thread.
  390. */
  391. unsigned long thread_saved_pc(struct task_struct *tsk)
  392. {
  393. struct thread_struct *t = &tsk->thread;
  394. /* New born processes are a special case */
  395. if (t->reg31 == (unsigned long) ret_from_fork)
  396. return t->reg31;
  397. if (schedule_mfi.pc_offset < 0)
  398. return 0;
  399. return ((unsigned long *)t->reg29)[schedule_mfi.pc_offset];
  400. }
  401. #ifdef CONFIG_KALLSYMS
  402. /* generic stack unwinding function */
  403. unsigned long notrace unwind_stack_by_address(unsigned long stack_page,
  404. unsigned long *sp,
  405. unsigned long pc,
  406. unsigned long *ra)
  407. {
  408. struct mips_frame_info info;
  409. unsigned long size, ofs;
  410. int leaf;
  411. extern void ret_from_irq(void);
  412. extern void ret_from_exception(void);
  413. if (!stack_page)
  414. return 0;
  415. /*
  416. * If we reached the bottom of interrupt context,
  417. * return saved pc in pt_regs.
  418. */
  419. if (pc == (unsigned long)ret_from_irq ||
  420. pc == (unsigned long)ret_from_exception) {
  421. struct pt_regs *regs;
  422. if (*sp >= stack_page &&
  423. *sp + sizeof(*regs) <= stack_page + THREAD_SIZE - 32) {
  424. regs = (struct pt_regs *)*sp;
  425. pc = regs->cp0_epc;
  426. if (__kernel_text_address(pc)) {
  427. *sp = regs->regs[29];
  428. *ra = regs->regs[31];
  429. return pc;
  430. }
  431. }
  432. return 0;
  433. }
  434. if (!kallsyms_lookup_size_offset(pc, &size, &ofs))
  435. return 0;
  436. /*
  437. * Return ra if an exception occurred at the first instruction
  438. */
  439. if (unlikely(ofs == 0)) {
  440. pc = *ra;
  441. *ra = 0;
  442. return pc;
  443. }
  444. info.func = (void *)(pc - ofs);
  445. info.func_size = ofs; /* analyze from start to ofs */
  446. leaf = get_frame_info(&info);
  447. if (leaf < 0)
  448. return 0;
  449. if (*sp < stack_page ||
  450. *sp + info.frame_size > stack_page + THREAD_SIZE - 32)
  451. return 0;
  452. if (leaf)
  453. /*
  454. * For some extreme cases, get_frame_info() can
  455. * consider wrongly a nested function as a leaf
  456. * one. In that cases avoid to return always the
  457. * same value.
  458. */
  459. pc = pc != *ra ? *ra : 0;
  460. else
  461. pc = ((unsigned long *)(*sp))[info.pc_offset];
  462. *sp += info.frame_size;
  463. *ra = 0;
  464. return __kernel_text_address(pc) ? pc : 0;
  465. }
  466. EXPORT_SYMBOL(unwind_stack_by_address);
  467. /* used by show_backtrace() */
  468. unsigned long unwind_stack(struct task_struct *task, unsigned long *sp,
  469. unsigned long pc, unsigned long *ra)
  470. {
  471. unsigned long stack_page = (unsigned long)task_stack_page(task);
  472. return unwind_stack_by_address(stack_page, sp, pc, ra);
  473. }
  474. #endif
  475. /*
  476. * get_wchan - a maintenance nightmare^W^Wpain in the ass ...
  477. */
  478. unsigned long get_wchan(struct task_struct *task)
  479. {
  480. unsigned long pc = 0;
  481. #ifdef CONFIG_KALLSYMS
  482. unsigned long sp;
  483. unsigned long ra = 0;
  484. #endif
  485. if (!task || task == current || task->state == TASK_RUNNING)
  486. goto out;
  487. if (!task_stack_page(task))
  488. goto out;
  489. pc = thread_saved_pc(task);
  490. #ifdef CONFIG_KALLSYMS
  491. sp = task->thread.reg29 + schedule_mfi.frame_size;
  492. while (in_sched_functions(pc))
  493. pc = unwind_stack(task, &sp, pc, &ra);
  494. #endif
  495. out:
  496. return pc;
  497. }
  498. /*
  499. * Don't forget that the stack pointer must be aligned on a 8 bytes
  500. * boundary for 32-bits ABI and 16 bytes for 64-bits ABI.
  501. */
  502. unsigned long arch_align_stack(unsigned long sp)
  503. {
  504. if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
  505. sp -= get_random_int() & ~PAGE_MASK;
  506. return sp & ALMASK;
  507. }