signal_64.c 16 KB

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  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/unistd.h>
  35. #include <asm/cacheflush.h>
  36. #include <asm/vdso.h>
  37. #define DEBUG_SIG 0
  38. #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
  39. #define GP_REGS_SIZE min(sizeof(elf_gregset_t), sizeof(struct pt_regs))
  40. #define FP_REGS_SIZE sizeof(elf_fpregset_t)
  41. #define TRAMP_TRACEBACK 3
  42. #define TRAMP_SIZE 6
  43. /*
  44. * When we have signals to deliver, we set up on the user stack,
  45. * going down from the original stack pointer:
  46. * 1) a rt_sigframe struct which contains the ucontext
  47. * 2) a gap of __SIGNAL_FRAMESIZE bytes which acts as a dummy caller
  48. * frame for the signal handler.
  49. */
  50. struct rt_sigframe {
  51. /* sys_rt_sigreturn requires the ucontext be the first field */
  52. struct ucontext uc;
  53. unsigned long _unused[2];
  54. unsigned int tramp[TRAMP_SIZE];
  55. struct siginfo *pinfo;
  56. void *puc;
  57. struct siginfo info;
  58. /* 64 bit ABI allows for 288 bytes below sp before decrementing it. */
  59. char abigap[288];
  60. } __attribute__ ((aligned (16)));
  61. /*
  62. * Atomically swap in the new signal mask, and wait for a signal.
  63. */
  64. long sys_rt_sigsuspend(sigset_t __user *unewset, size_t sigsetsize, int p3, int p4,
  65. int p6, int p7, struct pt_regs *regs)
  66. {
  67. sigset_t saveset, newset;
  68. /* XXX: Don't preclude handling different sized sigset_t's. */
  69. if (sigsetsize != sizeof(sigset_t))
  70. return -EINVAL;
  71. if (copy_from_user(&newset, unewset, sizeof(newset)))
  72. return -EFAULT;
  73. sigdelsetmask(&newset, ~_BLOCKABLE);
  74. spin_lock_irq(&current->sighand->siglock);
  75. saveset = current->blocked;
  76. current->blocked = newset;
  77. recalc_sigpending();
  78. spin_unlock_irq(&current->sighand->siglock);
  79. regs->result = -EINTR;
  80. regs->gpr[3] = EINTR;
  81. regs->ccr |= 0x10000000;
  82. while (1) {
  83. current->state = TASK_INTERRUPTIBLE;
  84. schedule();
  85. if (do_signal(&saveset, regs))
  86. return 0;
  87. }
  88. }
  89. long sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss, unsigned long r5,
  90. unsigned long r6, unsigned long r7, unsigned long r8,
  91. struct pt_regs *regs)
  92. {
  93. return do_sigaltstack(uss, uoss, regs->gpr[1]);
  94. }
  95. /*
  96. * Set up the sigcontext for the signal frame.
  97. */
  98. static long setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs,
  99. int signr, sigset_t *set, unsigned long handler)
  100. {
  101. /* When CONFIG_ALTIVEC is set, we _always_ setup v_regs even if the
  102. * process never used altivec yet (MSR_VEC is zero in pt_regs of
  103. * the context). This is very important because we must ensure we
  104. * don't lose the VRSAVE content that may have been set prior to
  105. * the process doing its first vector operation
  106. * Userland shall check AT_HWCAP to know wether it can rely on the
  107. * v_regs pointer or not
  108. */
  109. #ifdef CONFIG_ALTIVEC
  110. elf_vrreg_t __user *v_regs = (elf_vrreg_t __user *)(((unsigned long)sc->vmx_reserve + 15) & ~0xful);
  111. #endif
  112. long err = 0;
  113. flush_fp_to_thread(current);
  114. /* Make sure signal doesn't get spurrious FP exceptions */
  115. current->thread.fpscr.val = 0;
  116. #ifdef CONFIG_ALTIVEC
  117. err |= __put_user(v_regs, &sc->v_regs);
  118. /* save altivec registers */
  119. if (current->thread.used_vr) {
  120. flush_altivec_to_thread(current);
  121. /* Copy 33 vec registers (vr0..31 and vscr) to the stack */
  122. err |= __copy_to_user(v_regs, current->thread.vr, 33 * sizeof(vector128));
  123. /* set MSR_VEC in the MSR value in the frame to indicate that sc->v_reg)
  124. * contains valid data.
  125. */
  126. regs->msr |= MSR_VEC;
  127. }
  128. /* We always copy to/from vrsave, it's 0 if we don't have or don't
  129. * use altivec.
  130. */
  131. err |= __put_user(current->thread.vrsave, (u32 __user *)&v_regs[33]);
  132. #else /* CONFIG_ALTIVEC */
  133. err |= __put_user(0, &sc->v_regs);
  134. #endif /* CONFIG_ALTIVEC */
  135. err |= __put_user(&sc->gp_regs, &sc->regs);
  136. err |= __copy_to_user(&sc->gp_regs, regs, GP_REGS_SIZE);
  137. err |= __copy_to_user(&sc->fp_regs, &current->thread.fpr, FP_REGS_SIZE);
  138. err |= __put_user(signr, &sc->signal);
  139. err |= __put_user(handler, &sc->handler);
  140. if (set != NULL)
  141. err |= __put_user(set->sig[0], &sc->oldmask);
  142. return err;
  143. }
  144. /*
  145. * Restore the sigcontext from the signal frame.
  146. */
  147. static long restore_sigcontext(struct pt_regs *regs, sigset_t *set, int sig,
  148. struct sigcontext __user *sc)
  149. {
  150. #ifdef CONFIG_ALTIVEC
  151. elf_vrreg_t __user *v_regs;
  152. #endif
  153. unsigned long err = 0;
  154. unsigned long save_r13 = 0;
  155. elf_greg_t *gregs = (elf_greg_t *)regs;
  156. #ifdef CONFIG_ALTIVEC
  157. unsigned long msr;
  158. #endif
  159. int i;
  160. /* If this is not a signal return, we preserve the TLS in r13 */
  161. if (!sig)
  162. save_r13 = regs->gpr[13];
  163. /* copy everything before MSR */
  164. err |= __copy_from_user(regs, &sc->gp_regs,
  165. PT_MSR*sizeof(unsigned long));
  166. /* skip MSR and SOFTE */
  167. for (i = PT_MSR+1; i <= PT_RESULT; i++) {
  168. if (i == PT_SOFTE)
  169. continue;
  170. err |= __get_user(gregs[i], &sc->gp_regs[i]);
  171. }
  172. if (!sig)
  173. regs->gpr[13] = save_r13;
  174. err |= __copy_from_user(&current->thread.fpr, &sc->fp_regs, FP_REGS_SIZE);
  175. if (set != NULL)
  176. err |= __get_user(set->sig[0], &sc->oldmask);
  177. #ifdef CONFIG_ALTIVEC
  178. err |= __get_user(v_regs, &sc->v_regs);
  179. err |= __get_user(msr, &sc->gp_regs[PT_MSR]);
  180. if (err)
  181. return err;
  182. /* Copy 33 vec registers (vr0..31 and vscr) from the stack */
  183. if (v_regs != 0 && (msr & MSR_VEC) != 0)
  184. err |= __copy_from_user(current->thread.vr, v_regs,
  185. 33 * sizeof(vector128));
  186. else if (current->thread.used_vr)
  187. memset(current->thread.vr, 0, 33 * sizeof(vector128));
  188. /* Always get VRSAVE back */
  189. if (v_regs != 0)
  190. err |= __get_user(current->thread.vrsave, (u32 __user *)&v_regs[33]);
  191. else
  192. current->thread.vrsave = 0;
  193. #endif /* CONFIG_ALTIVEC */
  194. #ifndef CONFIG_SMP
  195. preempt_disable();
  196. if (last_task_used_math == current)
  197. last_task_used_math = NULL;
  198. if (last_task_used_altivec == current)
  199. last_task_used_altivec = NULL;
  200. preempt_enable();
  201. #endif
  202. /* Force reload of FP/VEC */
  203. regs->msr &= ~(MSR_FP | MSR_FE0 | MSR_FE1 | MSR_VEC);
  204. return err;
  205. }
  206. /*
  207. * Allocate space for the signal frame
  208. */
  209. static inline void __user * get_sigframe(struct k_sigaction *ka, struct pt_regs *regs,
  210. size_t frame_size)
  211. {
  212. unsigned long newsp;
  213. /* Default to using normal stack */
  214. newsp = regs->gpr[1];
  215. if (ka->sa.sa_flags & SA_ONSTACK) {
  216. if (! on_sig_stack(regs->gpr[1]))
  217. newsp = (current->sas_ss_sp + current->sas_ss_size);
  218. }
  219. return (void __user *)((newsp - frame_size) & -16ul);
  220. }
  221. /*
  222. * Setup the trampoline code on the stack
  223. */
  224. static long setup_trampoline(unsigned int syscall, unsigned int __user *tramp)
  225. {
  226. int i;
  227. long err = 0;
  228. /* addi r1, r1, __SIGNAL_FRAMESIZE # Pop the dummy stackframe */
  229. err |= __put_user(0x38210000UL | (__SIGNAL_FRAMESIZE & 0xffff), &tramp[0]);
  230. /* li r0, __NR_[rt_]sigreturn| */
  231. err |= __put_user(0x38000000UL | (syscall & 0xffff), &tramp[1]);
  232. /* sc */
  233. err |= __put_user(0x44000002UL, &tramp[2]);
  234. /* Minimal traceback info */
  235. for (i=TRAMP_TRACEBACK; i < TRAMP_SIZE ;i++)
  236. err |= __put_user(0, &tramp[i]);
  237. if (!err)
  238. flush_icache_range((unsigned long) &tramp[0],
  239. (unsigned long) &tramp[TRAMP_SIZE]);
  240. return err;
  241. }
  242. /*
  243. * Restore the user process's signal mask (also used by signal32.c)
  244. */
  245. void restore_sigmask(sigset_t *set)
  246. {
  247. sigdelsetmask(set, ~_BLOCKABLE);
  248. spin_lock_irq(&current->sighand->siglock);
  249. current->blocked = *set;
  250. recalc_sigpending();
  251. spin_unlock_irq(&current->sighand->siglock);
  252. }
  253. /*
  254. * Handle {get,set,swap}_context operations
  255. */
  256. int sys_swapcontext(struct ucontext __user *old_ctx,
  257. struct ucontext __user *new_ctx,
  258. long ctx_size, long r6, long r7, long r8, struct pt_regs *regs)
  259. {
  260. unsigned char tmp;
  261. sigset_t set;
  262. /* Context size is for future use. Right now, we only make sure
  263. * we are passed something we understand
  264. */
  265. if (ctx_size < sizeof(struct ucontext))
  266. return -EINVAL;
  267. if (old_ctx != NULL) {
  268. if (!access_ok(VERIFY_WRITE, old_ctx, sizeof(*old_ctx))
  269. || setup_sigcontext(&old_ctx->uc_mcontext, regs, 0, NULL, 0)
  270. || __copy_to_user(&old_ctx->uc_sigmask,
  271. &current->blocked, sizeof(sigset_t)))
  272. return -EFAULT;
  273. }
  274. if (new_ctx == NULL)
  275. return 0;
  276. if (!access_ok(VERIFY_READ, new_ctx, sizeof(*new_ctx))
  277. || __get_user(tmp, (u8 __user *) new_ctx)
  278. || __get_user(tmp, (u8 __user *) (new_ctx + 1) - 1))
  279. return -EFAULT;
  280. /*
  281. * If we get a fault copying the context into the kernel's
  282. * image of the user's registers, we can't just return -EFAULT
  283. * because the user's registers will be corrupted. For instance
  284. * the NIP value may have been updated but not some of the
  285. * other registers. Given that we have done the access_ok
  286. * and successfully read the first and last bytes of the region
  287. * above, this should only happen in an out-of-memory situation
  288. * or if another thread unmaps the region containing the context.
  289. * We kill the task with a SIGSEGV in this situation.
  290. */
  291. if (__copy_from_user(&set, &new_ctx->uc_sigmask, sizeof(set)))
  292. do_exit(SIGSEGV);
  293. restore_sigmask(&set);
  294. if (restore_sigcontext(regs, NULL, 0, &new_ctx->uc_mcontext))
  295. do_exit(SIGSEGV);
  296. /* This returns like rt_sigreturn */
  297. return 0;
  298. }
  299. /*
  300. * Do a signal return; undo the signal stack.
  301. */
  302. int sys_rt_sigreturn(unsigned long r3, unsigned long r4, unsigned long r5,
  303. unsigned long r6, unsigned long r7, unsigned long r8,
  304. struct pt_regs *regs)
  305. {
  306. struct ucontext __user *uc = (struct ucontext __user *)regs->gpr[1];
  307. sigset_t set;
  308. /* Always make any pending restarted system calls return -EINTR */
  309. current_thread_info()->restart_block.fn = do_no_restart_syscall;
  310. if (!access_ok(VERIFY_READ, uc, sizeof(*uc)))
  311. goto badframe;
  312. if (__copy_from_user(&set, &uc->uc_sigmask, sizeof(set)))
  313. goto badframe;
  314. restore_sigmask(&set);
  315. if (restore_sigcontext(regs, NULL, 1, &uc->uc_mcontext))
  316. goto badframe;
  317. /* do_sigaltstack expects a __user pointer and won't modify
  318. * what's in there anyway
  319. */
  320. do_sigaltstack(&uc->uc_stack, NULL, regs->gpr[1]);
  321. return regs->result;
  322. badframe:
  323. #if DEBUG_SIG
  324. printk("badframe in sys_rt_sigreturn, regs=%p uc=%p &uc->uc_mcontext=%p\n",
  325. regs, uc, &uc->uc_mcontext);
  326. #endif
  327. force_sig(SIGSEGV, current);
  328. return 0;
  329. }
  330. static int setup_rt_frame(int signr, struct k_sigaction *ka, siginfo_t *info,
  331. sigset_t *set, struct pt_regs *regs)
  332. {
  333. /* Handler is *really* a pointer to the function descriptor for
  334. * the signal routine. The first entry in the function
  335. * descriptor is the entry address of signal and the second
  336. * entry is the TOC value we need to use.
  337. */
  338. func_descr_t __user *funct_desc_ptr;
  339. struct rt_sigframe __user *frame;
  340. unsigned long newsp = 0;
  341. long err = 0;
  342. frame = get_sigframe(ka, regs, sizeof(*frame));
  343. if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
  344. goto badframe;
  345. err |= __put_user(&frame->info, &frame->pinfo);
  346. err |= __put_user(&frame->uc, &frame->puc);
  347. err |= copy_siginfo_to_user(&frame->info, info);
  348. if (err)
  349. goto badframe;
  350. /* Create the ucontext. */
  351. err |= __put_user(0, &frame->uc.uc_flags);
  352. err |= __put_user(0, &frame->uc.uc_link);
  353. err |= __put_user(current->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
  354. err |= __put_user(sas_ss_flags(regs->gpr[1]),
  355. &frame->uc.uc_stack.ss_flags);
  356. err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
  357. err |= setup_sigcontext(&frame->uc.uc_mcontext, regs, signr, NULL,
  358. (unsigned long)ka->sa.sa_handler);
  359. err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
  360. if (err)
  361. goto badframe;
  362. /* Set up to return from userspace. */
  363. if (vdso64_rt_sigtramp && current->thread.vdso_base) {
  364. regs->link = current->thread.vdso_base + vdso64_rt_sigtramp;
  365. } else {
  366. err |= setup_trampoline(__NR_rt_sigreturn, &frame->tramp[0]);
  367. if (err)
  368. goto badframe;
  369. regs->link = (unsigned long) &frame->tramp[0];
  370. }
  371. funct_desc_ptr = (func_descr_t __user *) ka->sa.sa_handler;
  372. /* Allocate a dummy caller frame for the signal handler. */
  373. newsp = (unsigned long)frame - __SIGNAL_FRAMESIZE;
  374. err |= put_user(regs->gpr[1], (unsigned long __user *)newsp);
  375. /* Set up "regs" so we "return" to the signal handler. */
  376. err |= get_user(regs->nip, &funct_desc_ptr->entry);
  377. regs->gpr[1] = newsp;
  378. err |= get_user(regs->gpr[2], &funct_desc_ptr->toc);
  379. regs->gpr[3] = signr;
  380. regs->result = 0;
  381. if (ka->sa.sa_flags & SA_SIGINFO) {
  382. err |= get_user(regs->gpr[4], (unsigned long __user *)&frame->pinfo);
  383. err |= get_user(regs->gpr[5], (unsigned long __user *)&frame->puc);
  384. regs->gpr[6] = (unsigned long) frame;
  385. } else {
  386. regs->gpr[4] = (unsigned long)&frame->uc.uc_mcontext;
  387. }
  388. if (err)
  389. goto badframe;
  390. if (test_thread_flag(TIF_SINGLESTEP))
  391. ptrace_notify(SIGTRAP);
  392. return 1;
  393. badframe:
  394. #if DEBUG_SIG
  395. printk("badframe in setup_rt_frame, regs=%p frame=%p newsp=%lx\n",
  396. regs, frame, newsp);
  397. #endif
  398. force_sigsegv(signr, current);
  399. return 0;
  400. }
  401. /*
  402. * OK, we're invoking a handler
  403. */
  404. static int handle_signal(unsigned long sig, struct k_sigaction *ka,
  405. siginfo_t *info, sigset_t *oldset, struct pt_regs *regs)
  406. {
  407. int ret;
  408. /* Set up Signal Frame */
  409. ret = setup_rt_frame(sig, ka, info, oldset, regs);
  410. if (ret) {
  411. spin_lock_irq(&current->sighand->siglock);
  412. sigorsets(&current->blocked, &current->blocked, &ka->sa.sa_mask);
  413. if (!(ka->sa.sa_flags & SA_NODEFER))
  414. sigaddset(&current->blocked,sig);
  415. recalc_sigpending();
  416. spin_unlock_irq(&current->sighand->siglock);
  417. }
  418. return ret;
  419. }
  420. static inline void syscall_restart(struct pt_regs *regs, struct k_sigaction *ka)
  421. {
  422. switch ((int)regs->result) {
  423. case -ERESTART_RESTARTBLOCK:
  424. case -ERESTARTNOHAND:
  425. /* ERESTARTNOHAND means that the syscall should only be
  426. * restarted if there was no handler for the signal, and since
  427. * we only get here if there is a handler, we dont restart.
  428. */
  429. regs->result = -EINTR;
  430. break;
  431. case -ERESTARTSYS:
  432. /* ERESTARTSYS means to restart the syscall if there is no
  433. * handler or the handler was registered with SA_RESTART
  434. */
  435. if (!(ka->sa.sa_flags & SA_RESTART)) {
  436. regs->result = -EINTR;
  437. break;
  438. }
  439. /* fallthrough */
  440. case -ERESTARTNOINTR:
  441. /* ERESTARTNOINTR means that the syscall should be
  442. * called again after the signal handler returns.
  443. */
  444. regs->gpr[3] = regs->orig_gpr3;
  445. regs->nip -= 4;
  446. regs->result = 0;
  447. break;
  448. }
  449. }
  450. /*
  451. * Note that 'init' is a special process: it doesn't get signals it doesn't
  452. * want to handle. Thus you cannot kill init even with a SIGKILL even by
  453. * mistake.
  454. */
  455. int do_signal(sigset_t *oldset, struct pt_regs *regs)
  456. {
  457. siginfo_t info;
  458. int signr;
  459. struct k_sigaction ka;
  460. /*
  461. * If the current thread is 32 bit - invoke the
  462. * 32 bit signal handling code
  463. */
  464. if (test_thread_flag(TIF_32BIT))
  465. return do_signal32(oldset, regs);
  466. if (!oldset)
  467. oldset = &current->blocked;
  468. signr = get_signal_to_deliver(&info, &ka, regs, NULL);
  469. if (signr > 0) {
  470. /* Whee! Actually deliver the signal. */
  471. if (TRAP(regs) == 0x0C00)
  472. syscall_restart(regs, &ka);
  473. /*
  474. * Reenable the DABR before delivering the signal to
  475. * user space. The DABR will have been cleared if it
  476. * triggered inside the kernel.
  477. */
  478. if (current->thread.dabr)
  479. set_dabr(current->thread.dabr);
  480. return handle_signal(signr, &ka, &info, oldset, regs);
  481. }
  482. if (TRAP(regs) == 0x0C00) { /* System Call! */
  483. if ((int)regs->result == -ERESTARTNOHAND ||
  484. (int)regs->result == -ERESTARTSYS ||
  485. (int)regs->result == -ERESTARTNOINTR) {
  486. regs->gpr[3] = regs->orig_gpr3;
  487. regs->nip -= 4; /* Back up & retry system call */
  488. regs->result = 0;
  489. } else if ((int)regs->result == -ERESTART_RESTARTBLOCK) {
  490. regs->gpr[0] = __NR_restart_syscall;
  491. regs->nip -= 4;
  492. regs->result = 0;
  493. }
  494. }
  495. return 0;
  496. }
  497. EXPORT_SYMBOL(do_signal);