/arch/ppc64/kernel/signal.c

https://bitbucket.org/evzijst/gittest · C · 575 lines · 363 code · 82 blank · 130 comment · 77 complexity · 103a9e87281c47b050c082bb18b814fa MD5 · raw file

  1. /*
  2. * linux/arch/ppc64/kernel/signal.c
  3. *
  4. * PowerPC version
  5. * Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
  6. *
  7. * Derived from "arch/i386/kernel/signal.c"
  8. * Copyright (C) 1991, 1992 Linus Torvalds
  9. * 1997-11-28 Modified for POSIX.1b signals by Richard Henderson
  10. *
  11. * This program is free software; you can redistribute it and/or
  12. * modify it under the terms of the GNU General Public License
  13. * as published by the Free Software Foundation; either version
  14. * 2 of the License, or (at your option) any later version.
  15. */
  16. #include <linux/config.h>
  17. #include <linux/sched.h>
  18. #include <linux/mm.h>
  19. #include <linux/smp.h>
  20. #include <linux/smp_lock.h>
  21. #include <linux/kernel.h>
  22. #include <linux/signal.h>
  23. #include <linux/errno.h>
  24. #include <linux/wait.h>
  25. #include <linux/unistd.h>
  26. #include <linux/stddef.h>
  27. #include <linux/elf.h>
  28. #include <linux/ptrace.h>
  29. #include <linux/module.h>
  30. #include <asm/sigcontext.h>
  31. #include <asm/ucontext.h>
  32. #include <asm/uaccess.h>
  33. #include <asm/pgtable.h>
  34. #include <asm/ppcdebug.h>
  35. #include <asm/unistd.h>
  36. #include <asm/cacheflush.h>
  37. #include <asm/vdso.h>
  38. #define DEBUG_SIG 0
  39. #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
  40. #ifndef MIN
  41. #define MIN(a,b) (((a) < (b)) ? (a) : (b))
  42. #endif
  43. #define GP_REGS_SIZE MIN(sizeof(elf_gregset_t), sizeof(struct pt_regs))
  44. #define FP_REGS_SIZE sizeof(elf_fpregset_t)
  45. #define TRAMP_TRACEBACK 3
  46. #define TRAMP_SIZE 6
  47. /*
  48. * When we have signals to deliver, we set up on the user stack,
  49. * going down from the original stack pointer:
  50. * 1) a rt_sigframe struct which contains the ucontext
  51. * 2) a gap of __SIGNAL_FRAMESIZE bytes which acts as a dummy caller
  52. * frame for the signal handler.
  53. */
  54. struct rt_sigframe {
  55. /* sys_rt_sigreturn requires the ucontext be the first field */
  56. struct ucontext uc;
  57. unsigned long _unused[2];
  58. unsigned int tramp[TRAMP_SIZE];
  59. struct siginfo *pinfo;
  60. void *puc;
  61. struct siginfo info;
  62. /* 64 bit ABI allows for 288 bytes below sp before decrementing it. */
  63. char abigap[288];
  64. } __attribute__ ((aligned (16)));
  65. /*
  66. * Atomically swap in the new signal mask, and wait for a signal.
  67. */
  68. long sys_rt_sigsuspend(sigset_t __user *unewset, size_t sigsetsize, int p3, int p4,
  69. int p6, int p7, struct pt_regs *regs)
  70. {
  71. sigset_t saveset, newset;
  72. /* XXX: Don't preclude handling different sized sigset_t's. */
  73. if (sigsetsize != sizeof(sigset_t))
  74. return -EINVAL;
  75. if (copy_from_user(&newset, unewset, sizeof(newset)))
  76. return -EFAULT;
  77. sigdelsetmask(&newset, ~_BLOCKABLE);
  78. spin_lock_irq(&current->sighand->siglock);
  79. saveset = current->blocked;
  80. current->blocked = newset;
  81. recalc_sigpending();
  82. spin_unlock_irq(&current->sighand->siglock);
  83. regs->result = -EINTR;
  84. regs->gpr[3] = EINTR;
  85. regs->ccr |= 0x10000000;
  86. while (1) {
  87. current->state = TASK_INTERRUPTIBLE;
  88. schedule();
  89. if (do_signal(&saveset, regs))
  90. return 0;
  91. }
  92. }
  93. long sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss, unsigned long r5,
  94. unsigned long r6, unsigned long r7, unsigned long r8,
  95. struct pt_regs *regs)
  96. {
  97. return do_sigaltstack(uss, uoss, regs->gpr[1]);
  98. }
  99. /*
  100. * Set up the sigcontext for the signal frame.
  101. */
  102. static long setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs,
  103. int signr, sigset_t *set, unsigned long handler)
  104. {
  105. /* When CONFIG_ALTIVEC is set, we _always_ setup v_regs even if the
  106. * process never used altivec yet (MSR_VEC is zero in pt_regs of
  107. * the context). This is very important because we must ensure we
  108. * don't lose the VRSAVE content that may have been set prior to
  109. * the process doing its first vector operation
  110. * Userland shall check AT_HWCAP to know wether it can rely on the
  111. * v_regs pointer or not
  112. */
  113. #ifdef CONFIG_ALTIVEC
  114. elf_vrreg_t __user *v_regs = (elf_vrreg_t __user *)(((unsigned long)sc->vmx_reserve + 15) & ~0xful);
  115. #endif
  116. long err = 0;
  117. flush_fp_to_thread(current);
  118. /* Make sure signal doesn't get spurrious FP exceptions */
  119. current->thread.fpscr = 0;
  120. #ifdef CONFIG_ALTIVEC
  121. err |= __put_user(v_regs, &sc->v_regs);
  122. /* save altivec registers */
  123. if (current->thread.used_vr) {
  124. flush_altivec_to_thread(current);
  125. /* Copy 33 vec registers (vr0..31 and vscr) to the stack */
  126. err |= __copy_to_user(v_regs, current->thread.vr, 33 * sizeof(vector128));
  127. /* set MSR_VEC in the MSR value in the frame to indicate that sc->v_reg)
  128. * contains valid data.
  129. */
  130. regs->msr |= MSR_VEC;
  131. }
  132. /* We always copy to/from vrsave, it's 0 if we don't have or don't
  133. * use altivec.
  134. */
  135. err |= __put_user(current->thread.vrsave, (u32 __user *)&v_regs[33]);
  136. #else /* CONFIG_ALTIVEC */
  137. err |= __put_user(0, &sc->v_regs);
  138. #endif /* CONFIG_ALTIVEC */
  139. err |= __put_user(&sc->gp_regs, &sc->regs);
  140. err |= __copy_to_user(&sc->gp_regs, regs, GP_REGS_SIZE);
  141. err |= __copy_to_user(&sc->fp_regs, &current->thread.fpr, FP_REGS_SIZE);
  142. err |= __put_user(signr, &sc->signal);
  143. err |= __put_user(handler, &sc->handler);
  144. if (set != NULL)
  145. err |= __put_user(set->sig[0], &sc->oldmask);
  146. return err;
  147. }
  148. /*
  149. * Restore the sigcontext from the signal frame.
  150. */
  151. static long restore_sigcontext(struct pt_regs *regs, sigset_t *set, int sig,
  152. struct sigcontext __user *sc)
  153. {
  154. #ifdef CONFIG_ALTIVEC
  155. elf_vrreg_t __user *v_regs;
  156. #endif
  157. unsigned long err = 0;
  158. unsigned long save_r13 = 0;
  159. elf_greg_t *gregs = (elf_greg_t *)regs;
  160. #ifdef CONFIG_ALTIVEC
  161. unsigned long msr;
  162. #endif
  163. int i;
  164. /* If this is not a signal return, we preserve the TLS in r13 */
  165. if (!sig)
  166. save_r13 = regs->gpr[13];
  167. /* copy everything before MSR */
  168. err |= __copy_from_user(regs, &sc->gp_regs,
  169. PT_MSR*sizeof(unsigned long));
  170. /* skip MSR and SOFTE */
  171. for (i = PT_MSR+1; i <= PT_RESULT; i++) {
  172. if (i == PT_SOFTE)
  173. continue;
  174. err |= __get_user(gregs[i], &sc->gp_regs[i]);
  175. }
  176. if (!sig)
  177. regs->gpr[13] = save_r13;
  178. err |= __copy_from_user(&current->thread.fpr, &sc->fp_regs, FP_REGS_SIZE);
  179. if (set != NULL)
  180. err |= __get_user(set->sig[0], &sc->oldmask);
  181. #ifdef CONFIG_ALTIVEC
  182. err |= __get_user(v_regs, &sc->v_regs);
  183. err |= __get_user(msr, &sc->gp_regs[PT_MSR]);
  184. if (err)
  185. return err;
  186. /* Copy 33 vec registers (vr0..31 and vscr) from the stack */
  187. if (v_regs != 0 && (msr & MSR_VEC) != 0)
  188. err |= __copy_from_user(current->thread.vr, v_regs,
  189. 33 * sizeof(vector128));
  190. else if (current->thread.used_vr)
  191. memset(current->thread.vr, 0, 33 * sizeof(vector128));
  192. /* Always get VRSAVE back */
  193. if (v_regs != 0)
  194. err |= __get_user(current->thread.vrsave, (u32 __user *)&v_regs[33]);
  195. else
  196. current->thread.vrsave = 0;
  197. #endif /* CONFIG_ALTIVEC */
  198. #ifndef CONFIG_SMP
  199. preempt_disable();
  200. if (last_task_used_math == current)
  201. last_task_used_math = NULL;
  202. if (last_task_used_altivec == current)
  203. last_task_used_altivec = NULL;
  204. preempt_enable();
  205. #endif
  206. /* Force reload of FP/VEC */
  207. regs->msr &= ~(MSR_FP | MSR_FE0 | MSR_FE1 | MSR_VEC);
  208. return err;
  209. }
  210. /*
  211. * Allocate space for the signal frame
  212. */
  213. static inline void __user * get_sigframe(struct k_sigaction *ka, struct pt_regs *regs,
  214. size_t frame_size)
  215. {
  216. unsigned long newsp;
  217. /* Default to using normal stack */
  218. newsp = regs->gpr[1];
  219. if (ka->sa.sa_flags & SA_ONSTACK) {
  220. if (! on_sig_stack(regs->gpr[1]))
  221. newsp = (current->sas_ss_sp + current->sas_ss_size);
  222. }
  223. return (void __user *)((newsp - frame_size) & -16ul);
  224. }
  225. /*
  226. * Setup the trampoline code on the stack
  227. */
  228. static long setup_trampoline(unsigned int syscall, unsigned int __user *tramp)
  229. {
  230. int i;
  231. long err = 0;
  232. /* addi r1, r1, __SIGNAL_FRAMESIZE # Pop the dummy stackframe */
  233. err |= __put_user(0x38210000UL | (__SIGNAL_FRAMESIZE & 0xffff), &tramp[0]);
  234. /* li r0, __NR_[rt_]sigreturn| */
  235. err |= __put_user(0x38000000UL | (syscall & 0xffff), &tramp[1]);
  236. /* sc */
  237. err |= __put_user(0x44000002UL, &tramp[2]);
  238. /* Minimal traceback info */
  239. for (i=TRAMP_TRACEBACK; i < TRAMP_SIZE ;i++)
  240. err |= __put_user(0, &tramp[i]);
  241. if (!err)
  242. flush_icache_range((unsigned long) &tramp[0],
  243. (unsigned long) &tramp[TRAMP_SIZE]);
  244. return err;
  245. }
  246. /*
  247. * Restore the user process's signal mask (also used by signal32.c)
  248. */
  249. void restore_sigmask(sigset_t *set)
  250. {
  251. sigdelsetmask(set, ~_BLOCKABLE);
  252. spin_lock_irq(&current->sighand->siglock);
  253. current->blocked = *set;
  254. recalc_sigpending();
  255. spin_unlock_irq(&current->sighand->siglock);
  256. }
  257. /*
  258. * Handle {get,set,swap}_context operations
  259. */
  260. int sys_swapcontext(struct ucontext __user *old_ctx,
  261. struct ucontext __user *new_ctx,
  262. long ctx_size, long r6, long r7, long r8, struct pt_regs *regs)
  263. {
  264. unsigned char tmp;
  265. sigset_t set;
  266. /* Context size is for future use. Right now, we only make sure
  267. * we are passed something we understand
  268. */
  269. if (ctx_size < sizeof(struct ucontext))
  270. return -EINVAL;
  271. if (old_ctx != NULL) {
  272. if (!access_ok(VERIFY_WRITE, old_ctx, sizeof(*old_ctx))
  273. || setup_sigcontext(&old_ctx->uc_mcontext, regs, 0, NULL, 0)
  274. || __copy_to_user(&old_ctx->uc_sigmask,
  275. &current->blocked, sizeof(sigset_t)))
  276. return -EFAULT;
  277. }
  278. if (new_ctx == NULL)
  279. return 0;
  280. if (!access_ok(VERIFY_READ, new_ctx, sizeof(*new_ctx))
  281. || __get_user(tmp, (u8 __user *) new_ctx)
  282. || __get_user(tmp, (u8 __user *) (new_ctx + 1) - 1))
  283. return -EFAULT;
  284. /*
  285. * If we get a fault copying the context into the kernel's
  286. * image of the user's registers, we can't just return -EFAULT
  287. * because the user's registers will be corrupted. For instance
  288. * the NIP value may have been updated but not some of the
  289. * other registers. Given that we have done the access_ok
  290. * and successfully read the first and last bytes of the region
  291. * above, this should only happen in an out-of-memory situation
  292. * or if another thread unmaps the region containing the context.
  293. * We kill the task with a SIGSEGV in this situation.
  294. */
  295. if (__copy_from_user(&set, &new_ctx->uc_sigmask, sizeof(set)))
  296. do_exit(SIGSEGV);
  297. restore_sigmask(&set);
  298. if (restore_sigcontext(regs, NULL, 0, &new_ctx->uc_mcontext))
  299. do_exit(SIGSEGV);
  300. /* This returns like rt_sigreturn */
  301. return 0;
  302. }
  303. /*
  304. * Do a signal return; undo the signal stack.
  305. */
  306. int sys_rt_sigreturn(unsigned long r3, unsigned long r4, unsigned long r5,
  307. unsigned long r6, unsigned long r7, unsigned long r8,
  308. struct pt_regs *regs)
  309. {
  310. struct ucontext __user *uc = (struct ucontext __user *)regs->gpr[1];
  311. sigset_t set;
  312. /* Always make any pending restarted system calls return -EINTR */
  313. current_thread_info()->restart_block.fn = do_no_restart_syscall;
  314. if (!access_ok(VERIFY_READ, uc, sizeof(*uc)))
  315. goto badframe;
  316. if (__copy_from_user(&set, &uc->uc_sigmask, sizeof(set)))
  317. goto badframe;
  318. restore_sigmask(&set);
  319. if (restore_sigcontext(regs, NULL, 1, &uc->uc_mcontext))
  320. goto badframe;
  321. /* do_sigaltstack expects a __user pointer and won't modify
  322. * what's in there anyway
  323. */
  324. do_sigaltstack(&uc->uc_stack, NULL, regs->gpr[1]);
  325. return regs->result;
  326. badframe:
  327. #if DEBUG_SIG
  328. printk("badframe in sys_rt_sigreturn, regs=%p uc=%p &uc->uc_mcontext=%p\n",
  329. regs, uc, &uc->uc_mcontext);
  330. #endif
  331. force_sig(SIGSEGV, current);
  332. return 0;
  333. }
  334. static int setup_rt_frame(int signr, struct k_sigaction *ka, siginfo_t *info,
  335. sigset_t *set, struct pt_regs *regs)
  336. {
  337. /* Handler is *really* a pointer to the function descriptor for
  338. * the signal routine. The first entry in the function
  339. * descriptor is the entry address of signal and the second
  340. * entry is the TOC value we need to use.
  341. */
  342. func_descr_t __user *funct_desc_ptr;
  343. struct rt_sigframe __user *frame;
  344. unsigned long newsp = 0;
  345. long err = 0;
  346. frame = get_sigframe(ka, regs, sizeof(*frame));
  347. if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
  348. goto badframe;
  349. err |= __put_user(&frame->info, &frame->pinfo);
  350. err |= __put_user(&frame->uc, &frame->puc);
  351. err |= copy_siginfo_to_user(&frame->info, info);
  352. if (err)
  353. goto badframe;
  354. /* Create the ucontext. */
  355. err |= __put_user(0, &frame->uc.uc_flags);
  356. err |= __put_user(0, &frame->uc.uc_link);
  357. err |= __put_user(current->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
  358. err |= __put_user(sas_ss_flags(regs->gpr[1]),
  359. &frame->uc.uc_stack.ss_flags);
  360. err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
  361. err |= setup_sigcontext(&frame->uc.uc_mcontext, regs, signr, NULL,
  362. (unsigned long)ka->sa.sa_handler);
  363. err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
  364. if (err)
  365. goto badframe;
  366. /* Set up to return from userspace. */
  367. if (vdso64_rt_sigtramp && current->thread.vdso_base) {
  368. regs->link = current->thread.vdso_base + vdso64_rt_sigtramp;
  369. } else {
  370. err |= setup_trampoline(__NR_rt_sigreturn, &frame->tramp[0]);
  371. if (err)
  372. goto badframe;
  373. regs->link = (unsigned long) &frame->tramp[0];
  374. }
  375. funct_desc_ptr = (func_descr_t __user *) ka->sa.sa_handler;
  376. /* Allocate a dummy caller frame for the signal handler. */
  377. newsp = (unsigned long)frame - __SIGNAL_FRAMESIZE;
  378. err |= put_user(regs->gpr[1], (unsigned long __user *)newsp);
  379. /* Set up "regs" so we "return" to the signal handler. */
  380. err |= get_user(regs->nip, &funct_desc_ptr->entry);
  381. regs->gpr[1] = newsp;
  382. err |= get_user(regs->gpr[2], &funct_desc_ptr->toc);
  383. regs->gpr[3] = signr;
  384. regs->result = 0;
  385. if (ka->sa.sa_flags & SA_SIGINFO) {
  386. err |= get_user(regs->gpr[4], (unsigned long __user *)&frame->pinfo);
  387. err |= get_user(regs->gpr[5], (unsigned long __user *)&frame->puc);
  388. regs->gpr[6] = (unsigned long) frame;
  389. } else {
  390. regs->gpr[4] = (unsigned long)&frame->uc.uc_mcontext;
  391. }
  392. if (err)
  393. goto badframe;
  394. if (test_thread_flag(TIF_SINGLESTEP))
  395. ptrace_notify(SIGTRAP);
  396. return 1;
  397. badframe:
  398. #if DEBUG_SIG
  399. printk("badframe in setup_rt_frame, regs=%p frame=%p newsp=%lx\n",
  400. regs, frame, newsp);
  401. #endif
  402. force_sigsegv(signr, current);
  403. return 0;
  404. }
  405. /*
  406. * OK, we're invoking a handler
  407. */
  408. static int handle_signal(unsigned long sig, struct k_sigaction *ka,
  409. siginfo_t *info, sigset_t *oldset, struct pt_regs *regs)
  410. {
  411. int ret;
  412. /* Set up Signal Frame */
  413. ret = setup_rt_frame(sig, ka, info, oldset, regs);
  414. if (ret && !(ka->sa.sa_flags & SA_NODEFER)) {
  415. spin_lock_irq(&current->sighand->siglock);
  416. sigorsets(&current->blocked, &current->blocked, &ka->sa.sa_mask);
  417. sigaddset(&current->blocked,sig);
  418. recalc_sigpending();
  419. spin_unlock_irq(&current->sighand->siglock);
  420. }
  421. return ret;
  422. }
  423. static inline void syscall_restart(struct pt_regs *regs, struct k_sigaction *ka)
  424. {
  425. switch ((int)regs->result) {
  426. case -ERESTART_RESTARTBLOCK:
  427. case -ERESTARTNOHAND:
  428. /* ERESTARTNOHAND means that the syscall should only be
  429. * restarted if there was no handler for the signal, and since
  430. * we only get here if there is a handler, we dont restart.
  431. */
  432. regs->result = -EINTR;
  433. break;
  434. case -ERESTARTSYS:
  435. /* ERESTARTSYS means to restart the syscall if there is no
  436. * handler or the handler was registered with SA_RESTART
  437. */
  438. if (!(ka->sa.sa_flags & SA_RESTART)) {
  439. regs->result = -EINTR;
  440. break;
  441. }
  442. /* fallthrough */
  443. case -ERESTARTNOINTR:
  444. /* ERESTARTNOINTR means that the syscall should be
  445. * called again after the signal handler returns.
  446. */
  447. regs->gpr[3] = regs->orig_gpr3;
  448. regs->nip -= 4;
  449. regs->result = 0;
  450. break;
  451. }
  452. }
  453. /*
  454. * Note that 'init' is a special process: it doesn't get signals it doesn't
  455. * want to handle. Thus you cannot kill init even with a SIGKILL even by
  456. * mistake.
  457. */
  458. int do_signal(sigset_t *oldset, struct pt_regs *regs)
  459. {
  460. siginfo_t info;
  461. int signr;
  462. struct k_sigaction ka;
  463. /*
  464. * If the current thread is 32 bit - invoke the
  465. * 32 bit signal handling code
  466. */
  467. if (test_thread_flag(TIF_32BIT))
  468. return do_signal32(oldset, regs);
  469. if (!oldset)
  470. oldset = &current->blocked;
  471. signr = get_signal_to_deliver(&info, &ka, regs, NULL);
  472. if (signr > 0) {
  473. /* Whee! Actually deliver the signal. */
  474. if (TRAP(regs) == 0x0C00)
  475. syscall_restart(regs, &ka);
  476. return handle_signal(signr, &ka, &info, oldset, regs);
  477. }
  478. if (TRAP(regs) == 0x0C00) { /* System Call! */
  479. if ((int)regs->result == -ERESTARTNOHAND ||
  480. (int)regs->result == -ERESTARTSYS ||
  481. (int)regs->result == -ERESTARTNOINTR) {
  482. regs->gpr[3] = regs->orig_gpr3;
  483. regs->nip -= 4; /* Back up & retry system call */
  484. regs->result = 0;
  485. } else if ((int)regs->result == -ERESTART_RESTARTBLOCK) {
  486. regs->gpr[0] = __NR_restart_syscall;
  487. regs->nip -= 4;
  488. regs->result = 0;
  489. }
  490. }
  491. return 0;
  492. }
  493. EXPORT_SYMBOL(do_signal);