signal.c 17 KB

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248249250251252253254255256257258259260261262263264265266267268269270271272273274275276277278279280281282283284285286287288289290291292293294295296297298299300301302303304305306307308309310311312313314315316317318319320321322323324325326327328329330331332333334335336337338339340341342343344345346347348349350351352353354355356357358359360361362363364365366367368369370371372373374375376377378379380381382383384385386387388389390391392393394395396397398399400401402403404405406407408409410411412413414415416417418419420421422423424425426427428429430431432433434435436437438439440441442443444445446447448449450451452453454455456457458459460461462463464465466467468469470471472473474475476477478479480481482483484485486487488489490491492493494495496497498499500501502503504505506507508509510511512513514515516517518519520521522523524525526527528529530531532533534535536537538539540541542543544545546547548549550551552553554555556557558559560561562563564565566567568569570571572573574575576577578579580581582583584585586587588589590591592593594595596597598599600601602603604605606607608609610611612613614615616617618619620621622623624625626627628629630631632633634635636637638639640641642643644645646647648649650651652653654655656657658659660661
  1. /*
  2. * linux/arch/i386/kernel/signal.c
  3. *
  4. * Copyright (C) 1991, 1992 Linus Torvalds
  5. *
  6. * 1997-11-28 Modified for POSIX.1b signals by Richard Henderson
  7. * 2000-06-20 Pentium III FXSR, SSE support by Gareth Hughes
  8. */
  9. #include <linux/sched.h>
  10. #include <linux/mm.h>
  11. #include <linux/smp.h>
  12. #include <linux/smp_lock.h>
  13. #include <linux/kernel.h>
  14. #include <linux/signal.h>
  15. #include <linux/errno.h>
  16. #include <linux/wait.h>
  17. #include <linux/unistd.h>
  18. #include <linux/stddef.h>
  19. #include <linux/personality.h>
  20. #include <linux/suspend.h>
  21. #include <linux/ptrace.h>
  22. #include <linux/elf.h>
  23. #include <linux/binfmts.h>
  24. #include <asm/processor.h>
  25. #include <asm/ucontext.h>
  26. #include <asm/uaccess.h>
  27. #include <asm/i387.h>
  28. #include "sigframe.h"
  29. #define DEBUG_SIG 0
  30. #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
  31. /*
  32. * Atomically swap in the new signal mask, and wait for a signal.
  33. */
  34. asmlinkage int
  35. sys_sigsuspend(int history0, int history1, old_sigset_t mask)
  36. {
  37. mask &= _BLOCKABLE;
  38. spin_lock_irq(&current->sighand->siglock);
  39. current->saved_sigmask = current->blocked;
  40. siginitset(&current->blocked, mask);
  41. recalc_sigpending();
  42. spin_unlock_irq(&current->sighand->siglock);
  43. current->state = TASK_INTERRUPTIBLE;
  44. schedule();
  45. set_thread_flag(TIF_RESTORE_SIGMASK);
  46. return -ERESTARTNOHAND;
  47. }
  48. asmlinkage int
  49. sys_sigaction(int sig, const struct old_sigaction __user *act,
  50. struct old_sigaction __user *oact)
  51. {
  52. struct k_sigaction new_ka, old_ka;
  53. int ret;
  54. if (act) {
  55. old_sigset_t mask;
  56. if (!access_ok(VERIFY_READ, act, sizeof(*act)) ||
  57. __get_user(new_ka.sa.sa_handler, &act->sa_handler) ||
  58. __get_user(new_ka.sa.sa_restorer, &act->sa_restorer))
  59. return -EFAULT;
  60. __get_user(new_ka.sa.sa_flags, &act->sa_flags);
  61. __get_user(mask, &act->sa_mask);
  62. siginitset(&new_ka.sa.sa_mask, mask);
  63. }
  64. ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
  65. if (!ret && oact) {
  66. if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) ||
  67. __put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||
  68. __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer))
  69. return -EFAULT;
  70. __put_user(old_ka.sa.sa_flags, &oact->sa_flags);
  71. __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask);
  72. }
  73. return ret;
  74. }
  75. asmlinkage int
  76. sys_sigaltstack(unsigned long ebx)
  77. {
  78. /* This is needed to make gcc realize it doesn't own the "struct pt_regs" */
  79. struct pt_regs *regs = (struct pt_regs *)&ebx;
  80. const stack_t __user *uss = (const stack_t __user *)ebx;
  81. stack_t __user *uoss = (stack_t __user *)regs->ecx;
  82. return do_sigaltstack(uss, uoss, regs->esp);
  83. }
  84. /*
  85. * Do a signal return; undo the signal stack.
  86. */
  87. static int
  88. restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc, int *peax)
  89. {
  90. unsigned int err = 0;
  91. /* Always make any pending restarted system calls return -EINTR */
  92. current_thread_info()->restart_block.fn = do_no_restart_syscall;
  93. #define COPY(x) err |= __get_user(regs->x, &sc->x)
  94. #define COPY_SEG(seg) \
  95. { unsigned short tmp; \
  96. err |= __get_user(tmp, &sc->seg); \
  97. regs->x##seg = tmp; }
  98. #define COPY_SEG_STRICT(seg) \
  99. { unsigned short tmp; \
  100. err |= __get_user(tmp, &sc->seg); \
  101. regs->x##seg = tmp|3; }
  102. #define GET_SEG(seg) \
  103. { unsigned short tmp; \
  104. err |= __get_user(tmp, &sc->seg); \
  105. loadsegment(seg,tmp); }
  106. #define FIX_EFLAGS (X86_EFLAGS_AC | X86_EFLAGS_RF | \
  107. X86_EFLAGS_OF | X86_EFLAGS_DF | \
  108. X86_EFLAGS_TF | X86_EFLAGS_SF | X86_EFLAGS_ZF | \
  109. X86_EFLAGS_AF | X86_EFLAGS_PF | X86_EFLAGS_CF)
  110. GET_SEG(gs);
  111. COPY_SEG(fs);
  112. COPY_SEG(es);
  113. COPY_SEG(ds);
  114. COPY(edi);
  115. COPY(esi);
  116. COPY(ebp);
  117. COPY(esp);
  118. COPY(ebx);
  119. COPY(edx);
  120. COPY(ecx);
  121. COPY(eip);
  122. COPY_SEG_STRICT(cs);
  123. COPY_SEG_STRICT(ss);
  124. {
  125. unsigned int tmpflags;
  126. err |= __get_user(tmpflags, &sc->eflags);
  127. regs->eflags = (regs->eflags & ~FIX_EFLAGS) | (tmpflags & FIX_EFLAGS);
  128. regs->orig_eax = -1; /* disable syscall checks */
  129. }
  130. {
  131. struct _fpstate __user * buf;
  132. err |= __get_user(buf, &sc->fpstate);
  133. if (buf) {
  134. if (!access_ok(VERIFY_READ, buf, sizeof(*buf)))
  135. goto badframe;
  136. err |= restore_i387(buf);
  137. } else {
  138. struct task_struct *me = current;
  139. if (used_math()) {
  140. clear_fpu(me);
  141. clear_used_math();
  142. }
  143. }
  144. }
  145. err |= __get_user(*peax, &sc->eax);
  146. return err;
  147. badframe:
  148. return 1;
  149. }
  150. asmlinkage int sys_sigreturn(unsigned long __unused)
  151. {
  152. struct pt_regs *regs = (struct pt_regs *) &__unused;
  153. struct sigframe __user *frame = (struct sigframe __user *)(regs->esp - 8);
  154. sigset_t set;
  155. int eax;
  156. if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
  157. goto badframe;
  158. if (__get_user(set.sig[0], &frame->sc.oldmask)
  159. || (_NSIG_WORDS > 1
  160. && __copy_from_user(&set.sig[1], &frame->extramask,
  161. sizeof(frame->extramask))))
  162. goto badframe;
  163. sigdelsetmask(&set, ~_BLOCKABLE);
  164. spin_lock_irq(&current->sighand->siglock);
  165. current->blocked = set;
  166. recalc_sigpending();
  167. spin_unlock_irq(&current->sighand->siglock);
  168. if (restore_sigcontext(regs, &frame->sc, &eax))
  169. goto badframe;
  170. return eax;
  171. badframe:
  172. force_sig(SIGSEGV, current);
  173. return 0;
  174. }
  175. asmlinkage int sys_rt_sigreturn(unsigned long __unused)
  176. {
  177. struct pt_regs *regs = (struct pt_regs *) &__unused;
  178. struct rt_sigframe __user *frame = (struct rt_sigframe __user *)(regs->esp - 4);
  179. sigset_t set;
  180. int eax;
  181. if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
  182. goto badframe;
  183. if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
  184. goto badframe;
  185. sigdelsetmask(&set, ~_BLOCKABLE);
  186. spin_lock_irq(&current->sighand->siglock);
  187. current->blocked = set;
  188. recalc_sigpending();
  189. spin_unlock_irq(&current->sighand->siglock);
  190. if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &eax))
  191. goto badframe;
  192. if (do_sigaltstack(&frame->uc.uc_stack, NULL, regs->esp) == -EFAULT)
  193. goto badframe;
  194. return eax;
  195. badframe:
  196. force_sig(SIGSEGV, current);
  197. return 0;
  198. }
  199. /*
  200. * Set up a signal frame.
  201. */
  202. static int
  203. setup_sigcontext(struct sigcontext __user *sc, struct _fpstate __user *fpstate,
  204. struct pt_regs *regs, unsigned long mask)
  205. {
  206. int tmp, err = 0;
  207. err |= __put_user(regs->xfs, (unsigned int __user *)&sc->fs);
  208. savesegment(gs, tmp);
  209. err |= __put_user(tmp, (unsigned int __user *)&sc->gs);
  210. err |= __put_user(regs->xes, (unsigned int __user *)&sc->es);
  211. err |= __put_user(regs->xds, (unsigned int __user *)&sc->ds);
  212. err |= __put_user(regs->edi, &sc->edi);
  213. err |= __put_user(regs->esi, &sc->esi);
  214. err |= __put_user(regs->ebp, &sc->ebp);
  215. err |= __put_user(regs->esp, &sc->esp);
  216. err |= __put_user(regs->ebx, &sc->ebx);
  217. err |= __put_user(regs->edx, &sc->edx);
  218. err |= __put_user(regs->ecx, &sc->ecx);
  219. err |= __put_user(regs->eax, &sc->eax);
  220. err |= __put_user(current->thread.trap_no, &sc->trapno);
  221. err |= __put_user(current->thread.error_code, &sc->err);
  222. err |= __put_user(regs->eip, &sc->eip);
  223. err |= __put_user(regs->xcs, (unsigned int __user *)&sc->cs);
  224. err |= __put_user(regs->eflags, &sc->eflags);
  225. err |= __put_user(regs->esp, &sc->esp_at_signal);
  226. err |= __put_user(regs->xss, (unsigned int __user *)&sc->ss);
  227. tmp = save_i387(fpstate);
  228. if (tmp < 0)
  229. err = 1;
  230. else
  231. err |= __put_user(tmp ? fpstate : NULL, &sc->fpstate);
  232. /* non-iBCS2 extensions.. */
  233. err |= __put_user(mask, &sc->oldmask);
  234. err |= __put_user(current->thread.cr2, &sc->cr2);
  235. return err;
  236. }
  237. /*
  238. * Determine which stack to use..
  239. */
  240. static inline void __user *
  241. get_sigframe(struct k_sigaction *ka, struct pt_regs * regs, size_t frame_size)
  242. {
  243. unsigned long esp;
  244. /* Default to using normal stack */
  245. esp = regs->esp;
  246. /* This is the X/Open sanctioned signal stack switching. */
  247. if (ka->sa.sa_flags & SA_ONSTACK) {
  248. if (sas_ss_flags(esp) == 0)
  249. esp = current->sas_ss_sp + current->sas_ss_size;
  250. }
  251. /* This is the legacy signal stack switching. */
  252. else if ((regs->xss & 0xffff) != __USER_DS &&
  253. !(ka->sa.sa_flags & SA_RESTORER) &&
  254. ka->sa.sa_restorer) {
  255. esp = (unsigned long) ka->sa.sa_restorer;
  256. }
  257. esp -= frame_size;
  258. /* Align the stack pointer according to the i386 ABI,
  259. * i.e. so that on function entry ((sp + 4) & 15) == 0. */
  260. esp = ((esp + 4) & -16ul) - 4;
  261. return (void __user *) esp;
  262. }
  263. /* These symbols are defined with the addresses in the vsyscall page.
  264. See vsyscall-sigreturn.S. */
  265. extern void __user __kernel_sigreturn;
  266. extern void __user __kernel_rt_sigreturn;
  267. static int setup_frame(int sig, struct k_sigaction *ka,
  268. sigset_t *set, struct pt_regs * regs)
  269. {
  270. void __user *restorer;
  271. struct sigframe __user *frame;
  272. int err = 0;
  273. int usig;
  274. frame = get_sigframe(ka, regs, sizeof(*frame));
  275. if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
  276. goto give_sigsegv;
  277. usig = current_thread_info()->exec_domain
  278. && current_thread_info()->exec_domain->signal_invmap
  279. && sig < 32
  280. ? current_thread_info()->exec_domain->signal_invmap[sig]
  281. : sig;
  282. err = __put_user(usig, &frame->sig);
  283. if (err)
  284. goto give_sigsegv;
  285. err = setup_sigcontext(&frame->sc, &frame->fpstate, regs, set->sig[0]);
  286. if (err)
  287. goto give_sigsegv;
  288. if (_NSIG_WORDS > 1) {
  289. err = __copy_to_user(&frame->extramask, &set->sig[1],
  290. sizeof(frame->extramask));
  291. if (err)
  292. goto give_sigsegv;
  293. }
  294. if (current->binfmt->hasvdso)
  295. restorer = (void *)VDSO_SYM(&__kernel_sigreturn);
  296. else
  297. restorer = (void *)&frame->retcode;
  298. if (ka->sa.sa_flags & SA_RESTORER)
  299. restorer = ka->sa.sa_restorer;
  300. /* Set up to return from userspace. */
  301. err |= __put_user(restorer, &frame->pretcode);
  302. /*
  303. * This is popl %eax ; movl $,%eax ; int $0x80
  304. *
  305. * WE DO NOT USE IT ANY MORE! It's only left here for historical
  306. * reasons and because gdb uses it as a signature to notice
  307. * signal handler stack frames.
  308. */
  309. err |= __put_user(0xb858, (short __user *)(frame->retcode+0));
  310. err |= __put_user(__NR_sigreturn, (int __user *)(frame->retcode+2));
  311. err |= __put_user(0x80cd, (short __user *)(frame->retcode+6));
  312. if (err)
  313. goto give_sigsegv;
  314. /* Set up registers for signal handler */
  315. regs->esp = (unsigned long) frame;
  316. regs->eip = (unsigned long) ka->sa.sa_handler;
  317. regs->eax = (unsigned long) sig;
  318. regs->edx = (unsigned long) 0;
  319. regs->ecx = (unsigned long) 0;
  320. set_fs(USER_DS);
  321. regs->xds = __USER_DS;
  322. regs->xes = __USER_DS;
  323. regs->xss = __USER_DS;
  324. regs->xcs = __USER_CS;
  325. /*
  326. * Clear TF when entering the signal handler, but
  327. * notify any tracer that was single-stepping it.
  328. * The tracer may want to single-step inside the
  329. * handler too.
  330. */
  331. regs->eflags &= ~TF_MASK;
  332. if (test_thread_flag(TIF_SINGLESTEP))
  333. ptrace_notify(SIGTRAP);
  334. #if DEBUG_SIG
  335. printk("SIG deliver (%s:%d): sp=%p pc=%p ra=%p\n",
  336. current->comm, current->pid, frame, regs->eip, frame->pretcode);
  337. #endif
  338. return 0;
  339. give_sigsegv:
  340. force_sigsegv(sig, current);
  341. return -EFAULT;
  342. }
  343. static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
  344. sigset_t *set, struct pt_regs * regs)
  345. {
  346. void __user *restorer;
  347. struct rt_sigframe __user *frame;
  348. int err = 0;
  349. int usig;
  350. frame = get_sigframe(ka, regs, sizeof(*frame));
  351. if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
  352. goto give_sigsegv;
  353. usig = current_thread_info()->exec_domain
  354. && current_thread_info()->exec_domain->signal_invmap
  355. && sig < 32
  356. ? current_thread_info()->exec_domain->signal_invmap[sig]
  357. : sig;
  358. err |= __put_user(usig, &frame->sig);
  359. err |= __put_user(&frame->info, &frame->pinfo);
  360. err |= __put_user(&frame->uc, &frame->puc);
  361. err |= copy_siginfo_to_user(&frame->info, info);
  362. if (err)
  363. goto give_sigsegv;
  364. /* Create the ucontext. */
  365. err |= __put_user(0, &frame->uc.uc_flags);
  366. err |= __put_user(0, &frame->uc.uc_link);
  367. err |= __put_user(current->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
  368. err |= __put_user(sas_ss_flags(regs->esp),
  369. &frame->uc.uc_stack.ss_flags);
  370. err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
  371. err |= setup_sigcontext(&frame->uc.uc_mcontext, &frame->fpstate,
  372. regs, set->sig[0]);
  373. err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
  374. if (err)
  375. goto give_sigsegv;
  376. /* Set up to return from userspace. */
  377. restorer = (void *)VDSO_SYM(&__kernel_rt_sigreturn);
  378. if (ka->sa.sa_flags & SA_RESTORER)
  379. restorer = ka->sa.sa_restorer;
  380. err |= __put_user(restorer, &frame->pretcode);
  381. /*
  382. * This is movl $,%eax ; int $0x80
  383. *
  384. * WE DO NOT USE IT ANY MORE! It's only left here for historical
  385. * reasons and because gdb uses it as a signature to notice
  386. * signal handler stack frames.
  387. */
  388. err |= __put_user(0xb8, (char __user *)(frame->retcode+0));
  389. err |= __put_user(__NR_rt_sigreturn, (int __user *)(frame->retcode+1));
  390. err |= __put_user(0x80cd, (short __user *)(frame->retcode+5));
  391. if (err)
  392. goto give_sigsegv;
  393. /* Set up registers for signal handler */
  394. regs->esp = (unsigned long) frame;
  395. regs->eip = (unsigned long) ka->sa.sa_handler;
  396. regs->eax = (unsigned long) usig;
  397. regs->edx = (unsigned long) &frame->info;
  398. regs->ecx = (unsigned long) &frame->uc;
  399. set_fs(USER_DS);
  400. regs->xds = __USER_DS;
  401. regs->xes = __USER_DS;
  402. regs->xss = __USER_DS;
  403. regs->xcs = __USER_CS;
  404. /*
  405. * Clear TF when entering the signal handler, but
  406. * notify any tracer that was single-stepping it.
  407. * The tracer may want to single-step inside the
  408. * handler too.
  409. */
  410. regs->eflags &= ~TF_MASK;
  411. if (test_thread_flag(TIF_SINGLESTEP))
  412. ptrace_notify(SIGTRAP);
  413. #if DEBUG_SIG
  414. printk("SIG deliver (%s:%d): sp=%p pc=%p ra=%p\n",
  415. current->comm, current->pid, frame, regs->eip, frame->pretcode);
  416. #endif
  417. return 0;
  418. give_sigsegv:
  419. force_sigsegv(sig, current);
  420. return -EFAULT;
  421. }
  422. /*
  423. * OK, we're invoking a handler
  424. */
  425. static int
  426. handle_signal(unsigned long sig, siginfo_t *info, struct k_sigaction *ka,
  427. sigset_t *oldset, struct pt_regs * regs)
  428. {
  429. int ret;
  430. /* Are we from a system call? */
  431. if (regs->orig_eax >= 0) {
  432. /* If so, check system call restarting.. */
  433. switch (regs->eax) {
  434. case -ERESTART_RESTARTBLOCK:
  435. case -ERESTARTNOHAND:
  436. regs->eax = -EINTR;
  437. break;
  438. case -ERESTARTSYS:
  439. if (!(ka->sa.sa_flags & SA_RESTART)) {
  440. regs->eax = -EINTR;
  441. break;
  442. }
  443. /* fallthrough */
  444. case -ERESTARTNOINTR:
  445. regs->eax = regs->orig_eax;
  446. regs->eip -= 2;
  447. }
  448. }
  449. /*
  450. * If TF is set due to a debugger (PT_DTRACE), clear the TF flag so
  451. * that register information in the sigcontext is correct.
  452. */
  453. if (unlikely(regs->eflags & TF_MASK)
  454. && likely(current->ptrace & PT_DTRACE)) {
  455. current->ptrace &= ~PT_DTRACE;
  456. regs->eflags &= ~TF_MASK;
  457. }
  458. /* Set up the stack frame */
  459. if (ka->sa.sa_flags & SA_SIGINFO)
  460. ret = setup_rt_frame(sig, ka, info, oldset, regs);
  461. else
  462. ret = setup_frame(sig, ka, oldset, regs);
  463. if (ret == 0) {
  464. spin_lock_irq(&current->sighand->siglock);
  465. sigorsets(&current->blocked,&current->blocked,&ka->sa.sa_mask);
  466. if (!(ka->sa.sa_flags & SA_NODEFER))
  467. sigaddset(&current->blocked,sig);
  468. recalc_sigpending();
  469. spin_unlock_irq(&current->sighand->siglock);
  470. }
  471. return ret;
  472. }
  473. /*
  474. * Note that 'init' is a special process: it doesn't get signals it doesn't
  475. * want to handle. Thus you cannot kill init even with a SIGKILL even by
  476. * mistake.
  477. */
  478. static void fastcall do_signal(struct pt_regs *regs)
  479. {
  480. siginfo_t info;
  481. int signr;
  482. struct k_sigaction ka;
  483. sigset_t *oldset;
  484. /*
  485. * We want the common case to go fast, which
  486. * is why we may in certain cases get here from
  487. * kernel mode. Just return without doing anything
  488. * if so. vm86 regs switched out by assembly code
  489. * before reaching here, so testing against kernel
  490. * CS suffices.
  491. */
  492. if (!user_mode(regs))
  493. return;
  494. if (test_thread_flag(TIF_RESTORE_SIGMASK))
  495. oldset = &current->saved_sigmask;
  496. else
  497. oldset = &current->blocked;
  498. signr = get_signal_to_deliver(&info, &ka, regs, NULL);
  499. if (signr > 0) {
  500. /* Reenable any watchpoints before delivering the
  501. * signal to user space. The processor register will
  502. * have been cleared if the watchpoint triggered
  503. * inside the kernel.
  504. */
  505. if (unlikely(current->thread.debugreg[7]))
  506. set_debugreg(current->thread.debugreg[7], 7);
  507. /* Whee! Actually deliver the signal. */
  508. if (handle_signal(signr, &info, &ka, oldset, regs) == 0) {
  509. /* a signal was successfully delivered; the saved
  510. * sigmask will have been stored in the signal frame,
  511. * and will be restored by sigreturn, so we can simply
  512. * clear the TIF_RESTORE_SIGMASK flag */
  513. if (test_thread_flag(TIF_RESTORE_SIGMASK))
  514. clear_thread_flag(TIF_RESTORE_SIGMASK);
  515. }
  516. return;
  517. }
  518. /* Did we come from a system call? */
  519. if (regs->orig_eax >= 0) {
  520. /* Restart the system call - no handlers present */
  521. switch (regs->eax) {
  522. case -ERESTARTNOHAND:
  523. case -ERESTARTSYS:
  524. case -ERESTARTNOINTR:
  525. regs->eax = regs->orig_eax;
  526. regs->eip -= 2;
  527. break;
  528. case -ERESTART_RESTARTBLOCK:
  529. regs->eax = __NR_restart_syscall;
  530. regs->eip -= 2;
  531. break;
  532. }
  533. }
  534. /* if there's no signal to deliver, we just put the saved sigmask
  535. * back */
  536. if (test_thread_flag(TIF_RESTORE_SIGMASK)) {
  537. clear_thread_flag(TIF_RESTORE_SIGMASK);
  538. sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
  539. }
  540. }
  541. /*
  542. * notification of userspace execution resumption
  543. * - triggered by the TIF_WORK_MASK flags
  544. */
  545. __attribute__((regparm(3)))
  546. void do_notify_resume(struct pt_regs *regs, void *_unused,
  547. __u32 thread_info_flags)
  548. {
  549. /* Pending single-step? */
  550. if (thread_info_flags & _TIF_SINGLESTEP) {
  551. regs->eflags |= TF_MASK;
  552. clear_thread_flag(TIF_SINGLESTEP);
  553. }
  554. /* deal with pending signal delivery */
  555. if (thread_info_flags & (_TIF_SIGPENDING | _TIF_RESTORE_SIGMASK))
  556. do_signal(regs);
  557. clear_thread_flag(TIF_IRET);
  558. }