signal.c 20 KB

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  1. /*
  2. * Copyright (C) 1991, 1992 Linus Torvalds
  3. * Copyright (C) 2000, 2001, 2002 Andi Kleen SuSE Labs
  4. *
  5. * 1997-11-28 Modified for POSIX.1b signals by Richard Henderson
  6. * 2000-06-20 Pentium III FXSR, SSE support by Gareth Hughes
  7. * 2000-2002 x86-64 support by Andi Kleen
  8. */
  9. #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  10. #include <linux/sched.h>
  11. #include <linux/mm.h>
  12. #include <linux/smp.h>
  13. #include <linux/kernel.h>
  14. #include <linux/errno.h>
  15. #include <linux/wait.h>
  16. #include <linux/tracehook.h>
  17. #include <linux/unistd.h>
  18. #include <linux/stddef.h>
  19. #include <linux/personality.h>
  20. #include <linux/uaccess.h>
  21. #include <linux/user-return-notifier.h>
  22. #include <linux/uprobes.h>
  23. #include <linux/context_tracking.h>
  24. #include <asm/processor.h>
  25. #include <asm/ucontext.h>
  26. #include <asm/fpu-internal.h>
  27. #include <asm/vdso.h>
  28. #include <asm/mce.h>
  29. #include <asm/sighandling.h>
  30. #ifdef CONFIG_X86_64
  31. #include <asm/proto.h>
  32. #include <asm/ia32_unistd.h>
  33. #include <asm/sys_ia32.h>
  34. #endif /* CONFIG_X86_64 */
  35. #include <asm/syscall.h>
  36. #include <asm/syscalls.h>
  37. #include <asm/sigframe.h>
  38. #define COPY(x) do { \
  39. get_user_ex(regs->x, &sc->x); \
  40. } while (0)
  41. #define GET_SEG(seg) ({ \
  42. unsigned short tmp; \
  43. get_user_ex(tmp, &sc->seg); \
  44. tmp; \
  45. })
  46. #define COPY_SEG(seg) do { \
  47. regs->seg = GET_SEG(seg); \
  48. } while (0)
  49. #define COPY_SEG_CPL3(seg) do { \
  50. regs->seg = GET_SEG(seg) | 3; \
  51. } while (0)
  52. int restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc)
  53. {
  54. void __user *buf;
  55. unsigned int tmpflags;
  56. unsigned int err = 0;
  57. /* Always make any pending restarted system calls return -EINTR */
  58. current->restart_block.fn = do_no_restart_syscall;
  59. get_user_try {
  60. #ifdef CONFIG_X86_32
  61. set_user_gs(regs, GET_SEG(gs));
  62. COPY_SEG(fs);
  63. COPY_SEG(es);
  64. COPY_SEG(ds);
  65. #endif /* CONFIG_X86_32 */
  66. COPY(di); COPY(si); COPY(bp); COPY(sp); COPY(bx);
  67. COPY(dx); COPY(cx); COPY(ip); COPY(ax);
  68. #ifdef CONFIG_X86_64
  69. COPY(r8);
  70. COPY(r9);
  71. COPY(r10);
  72. COPY(r11);
  73. COPY(r12);
  74. COPY(r13);
  75. COPY(r14);
  76. COPY(r15);
  77. #endif /* CONFIG_X86_64 */
  78. COPY_SEG_CPL3(cs);
  79. COPY_SEG_CPL3(ss);
  80. get_user_ex(tmpflags, &sc->flags);
  81. regs->flags = (regs->flags & ~FIX_EFLAGS) | (tmpflags & FIX_EFLAGS);
  82. regs->orig_ax = -1; /* disable syscall checks */
  83. get_user_ex(buf, &sc->fpstate);
  84. } get_user_catch(err);
  85. err |= restore_xstate_sig(buf, config_enabled(CONFIG_X86_32));
  86. force_iret();
  87. return err;
  88. }
  89. int setup_sigcontext(struct sigcontext __user *sc, void __user *fpstate,
  90. struct pt_regs *regs, unsigned long mask)
  91. {
  92. int err = 0;
  93. put_user_try {
  94. #ifdef CONFIG_X86_32
  95. put_user_ex(get_user_gs(regs), (unsigned int __user *)&sc->gs);
  96. put_user_ex(regs->fs, (unsigned int __user *)&sc->fs);
  97. put_user_ex(regs->es, (unsigned int __user *)&sc->es);
  98. put_user_ex(regs->ds, (unsigned int __user *)&sc->ds);
  99. #endif /* CONFIG_X86_32 */
  100. put_user_ex(regs->di, &sc->di);
  101. put_user_ex(regs->si, &sc->si);
  102. put_user_ex(regs->bp, &sc->bp);
  103. put_user_ex(regs->sp, &sc->sp);
  104. put_user_ex(regs->bx, &sc->bx);
  105. put_user_ex(regs->dx, &sc->dx);
  106. put_user_ex(regs->cx, &sc->cx);
  107. put_user_ex(regs->ax, &sc->ax);
  108. #ifdef CONFIG_X86_64
  109. put_user_ex(regs->r8, &sc->r8);
  110. put_user_ex(regs->r9, &sc->r9);
  111. put_user_ex(regs->r10, &sc->r10);
  112. put_user_ex(regs->r11, &sc->r11);
  113. put_user_ex(regs->r12, &sc->r12);
  114. put_user_ex(regs->r13, &sc->r13);
  115. put_user_ex(regs->r14, &sc->r14);
  116. put_user_ex(regs->r15, &sc->r15);
  117. #endif /* CONFIG_X86_64 */
  118. put_user_ex(current->thread.trap_nr, &sc->trapno);
  119. put_user_ex(current->thread.error_code, &sc->err);
  120. put_user_ex(regs->ip, &sc->ip);
  121. #ifdef CONFIG_X86_32
  122. put_user_ex(regs->cs, (unsigned int __user *)&sc->cs);
  123. put_user_ex(regs->flags, &sc->flags);
  124. put_user_ex(regs->sp, &sc->sp_at_signal);
  125. put_user_ex(regs->ss, (unsigned int __user *)&sc->ss);
  126. #else /* !CONFIG_X86_32 */
  127. put_user_ex(regs->flags, &sc->flags);
  128. put_user_ex(regs->cs, &sc->cs);
  129. put_user_ex(0, &sc->__pad2);
  130. put_user_ex(0, &sc->__pad1);
  131. put_user_ex(regs->ss, &sc->ss);
  132. #endif /* CONFIG_X86_32 */
  133. put_user_ex(fpstate, &sc->fpstate);
  134. /* non-iBCS2 extensions.. */
  135. put_user_ex(mask, &sc->oldmask);
  136. put_user_ex(current->thread.cr2, &sc->cr2);
  137. } put_user_catch(err);
  138. return err;
  139. }
  140. /*
  141. * Set up a signal frame.
  142. */
  143. /*
  144. * Determine which stack to use..
  145. */
  146. static unsigned long align_sigframe(unsigned long sp)
  147. {
  148. #ifdef CONFIG_X86_32
  149. /*
  150. * Align the stack pointer according to the i386 ABI,
  151. * i.e. so that on function entry ((sp + 4) & 15) == 0.
  152. */
  153. sp = ((sp + 4) & -16ul) - 4;
  154. #else /* !CONFIG_X86_32 */
  155. sp = round_down(sp, 16) - 8;
  156. #endif
  157. return sp;
  158. }
  159. static inline void __user *
  160. get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size,
  161. void __user **fpstate)
  162. {
  163. /* Default to using normal stack */
  164. unsigned long math_size = 0;
  165. unsigned long sp = regs->sp;
  166. unsigned long buf_fx = 0;
  167. int onsigstack = on_sig_stack(sp);
  168. /* redzone */
  169. if (config_enabled(CONFIG_X86_64))
  170. sp -= 128;
  171. if (!onsigstack) {
  172. /* This is the X/Open sanctioned signal stack switching. */
  173. if (ka->sa.sa_flags & SA_ONSTACK) {
  174. if (current->sas_ss_size)
  175. sp = current->sas_ss_sp + current->sas_ss_size;
  176. } else if (config_enabled(CONFIG_X86_32) &&
  177. (regs->ss & 0xffff) != __USER_DS &&
  178. !(ka->sa.sa_flags & SA_RESTORER) &&
  179. ka->sa.sa_restorer) {
  180. /* This is the legacy signal stack switching. */
  181. sp = (unsigned long) ka->sa.sa_restorer;
  182. }
  183. }
  184. if (current->flags & PF_USED_MATH) {
  185. sp = alloc_mathframe(sp, config_enabled(CONFIG_X86_32),
  186. &buf_fx, &math_size);
  187. *fpstate = (void __user *)sp;
  188. }
  189. sp = align_sigframe(sp - frame_size);
  190. /*
  191. * If we are on the alternate signal stack and would overflow it, don't.
  192. * Return an always-bogus address instead so we will die with SIGSEGV.
  193. */
  194. if (onsigstack && !likely(on_sig_stack(sp)))
  195. return (void __user *)-1L;
  196. /* save i387 and extended state */
  197. if ((current->flags & PF_USED_MATH) &&
  198. save_xstate_sig(*fpstate, (void __user *)buf_fx, math_size) < 0)
  199. return (void __user *)-1L;
  200. return (void __user *)sp;
  201. }
  202. #ifdef CONFIG_X86_32
  203. static const struct {
  204. u16 poplmovl;
  205. u32 val;
  206. u16 int80;
  207. } __attribute__((packed)) retcode = {
  208. 0xb858, /* popl %eax; movl $..., %eax */
  209. __NR_sigreturn,
  210. 0x80cd, /* int $0x80 */
  211. };
  212. static const struct {
  213. u8 movl;
  214. u32 val;
  215. u16 int80;
  216. u8 pad;
  217. } __attribute__((packed)) rt_retcode = {
  218. 0xb8, /* movl $..., %eax */
  219. __NR_rt_sigreturn,
  220. 0x80cd, /* int $0x80 */
  221. 0
  222. };
  223. static int
  224. __setup_frame(int sig, struct ksignal *ksig, sigset_t *set,
  225. struct pt_regs *regs)
  226. {
  227. struct sigframe __user *frame;
  228. void __user *restorer;
  229. int err = 0;
  230. void __user *fpstate = NULL;
  231. frame = get_sigframe(&ksig->ka, regs, sizeof(*frame), &fpstate);
  232. if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
  233. return -EFAULT;
  234. if (__put_user(sig, &frame->sig))
  235. return -EFAULT;
  236. if (setup_sigcontext(&frame->sc, fpstate, regs, set->sig[0]))
  237. return -EFAULT;
  238. if (_NSIG_WORDS > 1) {
  239. if (__copy_to_user(&frame->extramask, &set->sig[1],
  240. sizeof(frame->extramask)))
  241. return -EFAULT;
  242. }
  243. if (current->mm->context.vdso)
  244. restorer = current->mm->context.vdso +
  245. selected_vdso32->sym___kernel_sigreturn;
  246. else
  247. restorer = &frame->retcode;
  248. if (ksig->ka.sa.sa_flags & SA_RESTORER)
  249. restorer = ksig->ka.sa.sa_restorer;
  250. /* Set up to return from userspace. */
  251. err |= __put_user(restorer, &frame->pretcode);
  252. /*
  253. * This is popl %eax ; movl $__NR_sigreturn, %eax ; int $0x80
  254. *
  255. * WE DO NOT USE IT ANY MORE! It's only left here for historical
  256. * reasons and because gdb uses it as a signature to notice
  257. * signal handler stack frames.
  258. */
  259. err |= __put_user(*((u64 *)&retcode), (u64 *)frame->retcode);
  260. if (err)
  261. return -EFAULT;
  262. /* Set up registers for signal handler */
  263. regs->sp = (unsigned long)frame;
  264. regs->ip = (unsigned long)ksig->ka.sa.sa_handler;
  265. regs->ax = (unsigned long)sig;
  266. regs->dx = 0;
  267. regs->cx = 0;
  268. regs->ds = __USER_DS;
  269. regs->es = __USER_DS;
  270. regs->ss = __USER_DS;
  271. regs->cs = __USER_CS;
  272. return 0;
  273. }
  274. static int __setup_rt_frame(int sig, struct ksignal *ksig,
  275. sigset_t *set, struct pt_regs *regs)
  276. {
  277. struct rt_sigframe __user *frame;
  278. void __user *restorer;
  279. int err = 0;
  280. void __user *fpstate = NULL;
  281. frame = get_sigframe(&ksig->ka, regs, sizeof(*frame), &fpstate);
  282. if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
  283. return -EFAULT;
  284. put_user_try {
  285. put_user_ex(sig, &frame->sig);
  286. put_user_ex(&frame->info, &frame->pinfo);
  287. put_user_ex(&frame->uc, &frame->puc);
  288. /* Create the ucontext. */
  289. if (cpu_has_xsave)
  290. put_user_ex(UC_FP_XSTATE, &frame->uc.uc_flags);
  291. else
  292. put_user_ex(0, &frame->uc.uc_flags);
  293. put_user_ex(0, &frame->uc.uc_link);
  294. save_altstack_ex(&frame->uc.uc_stack, regs->sp);
  295. /* Set up to return from userspace. */
  296. restorer = current->mm->context.vdso +
  297. selected_vdso32->sym___kernel_rt_sigreturn;
  298. if (ksig->ka.sa.sa_flags & SA_RESTORER)
  299. restorer = ksig->ka.sa.sa_restorer;
  300. put_user_ex(restorer, &frame->pretcode);
  301. /*
  302. * This is movl $__NR_rt_sigreturn, %ax ; int $0x80
  303. *
  304. * WE DO NOT USE IT ANY MORE! It's only left here for historical
  305. * reasons and because gdb uses it as a signature to notice
  306. * signal handler stack frames.
  307. */
  308. put_user_ex(*((u64 *)&rt_retcode), (u64 *)frame->retcode);
  309. } put_user_catch(err);
  310. err |= copy_siginfo_to_user(&frame->info, &ksig->info);
  311. err |= setup_sigcontext(&frame->uc.uc_mcontext, fpstate,
  312. regs, set->sig[0]);
  313. err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
  314. if (err)
  315. return -EFAULT;
  316. /* Set up registers for signal handler */
  317. regs->sp = (unsigned long)frame;
  318. regs->ip = (unsigned long)ksig->ka.sa.sa_handler;
  319. regs->ax = (unsigned long)sig;
  320. regs->dx = (unsigned long)&frame->info;
  321. regs->cx = (unsigned long)&frame->uc;
  322. regs->ds = __USER_DS;
  323. regs->es = __USER_DS;
  324. regs->ss = __USER_DS;
  325. regs->cs = __USER_CS;
  326. return 0;
  327. }
  328. #else /* !CONFIG_X86_32 */
  329. static int __setup_rt_frame(int sig, struct ksignal *ksig,
  330. sigset_t *set, struct pt_regs *regs)
  331. {
  332. struct rt_sigframe __user *frame;
  333. void __user *fp = NULL;
  334. int err = 0;
  335. frame = get_sigframe(&ksig->ka, regs, sizeof(struct rt_sigframe), &fp);
  336. if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
  337. return -EFAULT;
  338. if (ksig->ka.sa.sa_flags & SA_SIGINFO) {
  339. if (copy_siginfo_to_user(&frame->info, &ksig->info))
  340. return -EFAULT;
  341. }
  342. put_user_try {
  343. /* Create the ucontext. */
  344. if (cpu_has_xsave)
  345. put_user_ex(UC_FP_XSTATE, &frame->uc.uc_flags);
  346. else
  347. put_user_ex(0, &frame->uc.uc_flags);
  348. put_user_ex(0, &frame->uc.uc_link);
  349. save_altstack_ex(&frame->uc.uc_stack, regs->sp);
  350. /* Set up to return from userspace. If provided, use a stub
  351. already in userspace. */
  352. /* x86-64 should always use SA_RESTORER. */
  353. if (ksig->ka.sa.sa_flags & SA_RESTORER) {
  354. put_user_ex(ksig->ka.sa.sa_restorer, &frame->pretcode);
  355. } else {
  356. /* could use a vstub here */
  357. err |= -EFAULT;
  358. }
  359. } put_user_catch(err);
  360. err |= setup_sigcontext(&frame->uc.uc_mcontext, fp, regs, set->sig[0]);
  361. err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
  362. if (err)
  363. return -EFAULT;
  364. /* Set up registers for signal handler */
  365. regs->di = sig;
  366. /* In case the signal handler was declared without prototypes */
  367. regs->ax = 0;
  368. /* This also works for non SA_SIGINFO handlers because they expect the
  369. next argument after the signal number on the stack. */
  370. regs->si = (unsigned long)&frame->info;
  371. regs->dx = (unsigned long)&frame->uc;
  372. regs->ip = (unsigned long) ksig->ka.sa.sa_handler;
  373. regs->sp = (unsigned long)frame;
  374. /*
  375. * Set up the CS and SS registers to run signal handlers in
  376. * 64-bit mode, even if the handler happens to be interrupting
  377. * 32-bit or 16-bit code.
  378. *
  379. * SS is subtle. In 64-bit mode, we don't need any particular
  380. * SS descriptor, but we do need SS to be valid. It's possible
  381. * that the old SS is entirely bogus -- this can happen if the
  382. * signal we're trying to deliver is #GP or #SS caused by a bad
  383. * SS value.
  384. */
  385. regs->cs = __USER_CS;
  386. regs->ss = __USER_DS;
  387. return 0;
  388. }
  389. #endif /* CONFIG_X86_32 */
  390. static int x32_setup_rt_frame(struct ksignal *ksig,
  391. compat_sigset_t *set,
  392. struct pt_regs *regs)
  393. {
  394. #ifdef CONFIG_X86_X32_ABI
  395. struct rt_sigframe_x32 __user *frame;
  396. void __user *restorer;
  397. int err = 0;
  398. void __user *fpstate = NULL;
  399. frame = get_sigframe(&ksig->ka, regs, sizeof(*frame), &fpstate);
  400. if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
  401. return -EFAULT;
  402. if (ksig->ka.sa.sa_flags & SA_SIGINFO) {
  403. if (copy_siginfo_to_user32(&frame->info, &ksig->info))
  404. return -EFAULT;
  405. }
  406. put_user_try {
  407. /* Create the ucontext. */
  408. if (cpu_has_xsave)
  409. put_user_ex(UC_FP_XSTATE, &frame->uc.uc_flags);
  410. else
  411. put_user_ex(0, &frame->uc.uc_flags);
  412. put_user_ex(0, &frame->uc.uc_link);
  413. compat_save_altstack_ex(&frame->uc.uc_stack, regs->sp);
  414. put_user_ex(0, &frame->uc.uc__pad0);
  415. if (ksig->ka.sa.sa_flags & SA_RESTORER) {
  416. restorer = ksig->ka.sa.sa_restorer;
  417. } else {
  418. /* could use a vstub here */
  419. restorer = NULL;
  420. err |= -EFAULT;
  421. }
  422. put_user_ex(restorer, &frame->pretcode);
  423. } put_user_catch(err);
  424. err |= setup_sigcontext(&frame->uc.uc_mcontext, fpstate,
  425. regs, set->sig[0]);
  426. err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
  427. if (err)
  428. return -EFAULT;
  429. /* Set up registers for signal handler */
  430. regs->sp = (unsigned long) frame;
  431. regs->ip = (unsigned long) ksig->ka.sa.sa_handler;
  432. /* We use the x32 calling convention here... */
  433. regs->di = ksig->sig;
  434. regs->si = (unsigned long) &frame->info;
  435. regs->dx = (unsigned long) &frame->uc;
  436. loadsegment(ds, __USER_DS);
  437. loadsegment(es, __USER_DS);
  438. regs->cs = __USER_CS;
  439. regs->ss = __USER_DS;
  440. #endif /* CONFIG_X86_X32_ABI */
  441. return 0;
  442. }
  443. /*
  444. * Do a signal return; undo the signal stack.
  445. */
  446. #ifdef CONFIG_X86_32
  447. asmlinkage unsigned long sys_sigreturn(void)
  448. {
  449. struct pt_regs *regs = current_pt_regs();
  450. struct sigframe __user *frame;
  451. sigset_t set;
  452. frame = (struct sigframe __user *)(regs->sp - 8);
  453. if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
  454. goto badframe;
  455. if (__get_user(set.sig[0], &frame->sc.oldmask) || (_NSIG_WORDS > 1
  456. && __copy_from_user(&set.sig[1], &frame->extramask,
  457. sizeof(frame->extramask))))
  458. goto badframe;
  459. set_current_blocked(&set);
  460. if (restore_sigcontext(regs, &frame->sc))
  461. goto badframe;
  462. return regs->ax;
  463. badframe:
  464. signal_fault(regs, frame, "sigreturn");
  465. return 0;
  466. }
  467. #endif /* CONFIG_X86_32 */
  468. asmlinkage long sys_rt_sigreturn(void)
  469. {
  470. struct pt_regs *regs = current_pt_regs();
  471. struct rt_sigframe __user *frame;
  472. sigset_t set;
  473. frame = (struct rt_sigframe __user *)(regs->sp - sizeof(long));
  474. if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
  475. goto badframe;
  476. if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
  477. goto badframe;
  478. set_current_blocked(&set);
  479. if (restore_sigcontext(regs, &frame->uc.uc_mcontext))
  480. goto badframe;
  481. if (restore_altstack(&frame->uc.uc_stack))
  482. goto badframe;
  483. return regs->ax;
  484. badframe:
  485. signal_fault(regs, frame, "rt_sigreturn");
  486. return 0;
  487. }
  488. static int
  489. setup_rt_frame(struct ksignal *ksig, struct pt_regs *regs)
  490. {
  491. int usig = ksig->sig;
  492. sigset_t *set = sigmask_to_save();
  493. compat_sigset_t *cset = (compat_sigset_t *) set;
  494. /* Set up the stack frame */
  495. if (is_ia32_frame()) {
  496. if (ksig->ka.sa.sa_flags & SA_SIGINFO)
  497. return ia32_setup_rt_frame(usig, ksig, cset, regs);
  498. else
  499. return ia32_setup_frame(usig, ksig, cset, regs);
  500. } else if (is_x32_frame()) {
  501. return x32_setup_rt_frame(ksig, cset, regs);
  502. } else {
  503. return __setup_rt_frame(ksig->sig, ksig, set, regs);
  504. }
  505. }
  506. static void
  507. handle_signal(struct ksignal *ksig, struct pt_regs *regs)
  508. {
  509. bool stepping, failed;
  510. /* Are we from a system call? */
  511. if (syscall_get_nr(current, regs) >= 0) {
  512. /* If so, check system call restarting.. */
  513. switch (syscall_get_error(current, regs)) {
  514. case -ERESTART_RESTARTBLOCK:
  515. case -ERESTARTNOHAND:
  516. regs->ax = -EINTR;
  517. break;
  518. case -ERESTARTSYS:
  519. if (!(ksig->ka.sa.sa_flags & SA_RESTART)) {
  520. regs->ax = -EINTR;
  521. break;
  522. }
  523. /* fallthrough */
  524. case -ERESTARTNOINTR:
  525. regs->ax = regs->orig_ax;
  526. regs->ip -= 2;
  527. break;
  528. }
  529. }
  530. /*
  531. * If TF is set due to a debugger (TIF_FORCED_TF), clear TF now
  532. * so that register information in the sigcontext is correct and
  533. * then notify the tracer before entering the signal handler.
  534. */
  535. stepping = test_thread_flag(TIF_SINGLESTEP);
  536. if (stepping)
  537. user_disable_single_step(current);
  538. failed = (setup_rt_frame(ksig, regs) < 0);
  539. if (!failed) {
  540. /*
  541. * Clear the direction flag as per the ABI for function entry.
  542. *
  543. * Clear RF when entering the signal handler, because
  544. * it might disable possible debug exception from the
  545. * signal handler.
  546. *
  547. * Clear TF for the case when it wasn't set by debugger to
  548. * avoid the recursive send_sigtrap() in SIGTRAP handler.
  549. */
  550. regs->flags &= ~(X86_EFLAGS_DF|X86_EFLAGS_RF|X86_EFLAGS_TF);
  551. /*
  552. * Ensure the signal handler starts with the new fpu state.
  553. */
  554. if (current->flags & PF_USED_MATH)
  555. fpu_reset_state(current);
  556. }
  557. signal_setup_done(failed, ksig, stepping);
  558. }
  559. #ifdef CONFIG_X86_32
  560. #define NR_restart_syscall __NR_restart_syscall
  561. #else /* !CONFIG_X86_32 */
  562. #define NR_restart_syscall \
  563. test_thread_flag(TIF_IA32) ? __NR_ia32_restart_syscall : __NR_restart_syscall
  564. #endif /* CONFIG_X86_32 */
  565. /*
  566. * Note that 'init' is a special process: it doesn't get signals it doesn't
  567. * want to handle. Thus you cannot kill init even with a SIGKILL even by
  568. * mistake.
  569. */
  570. static void do_signal(struct pt_regs *regs)
  571. {
  572. struct ksignal ksig;
  573. if (get_signal(&ksig)) {
  574. /* Whee! Actually deliver the signal. */
  575. handle_signal(&ksig, regs);
  576. return;
  577. }
  578. /* Did we come from a system call? */
  579. if (syscall_get_nr(current, regs) >= 0) {
  580. /* Restart the system call - no handlers present */
  581. switch (syscall_get_error(current, regs)) {
  582. case -ERESTARTNOHAND:
  583. case -ERESTARTSYS:
  584. case -ERESTARTNOINTR:
  585. regs->ax = regs->orig_ax;
  586. regs->ip -= 2;
  587. break;
  588. case -ERESTART_RESTARTBLOCK:
  589. regs->ax = NR_restart_syscall;
  590. regs->ip -= 2;
  591. break;
  592. }
  593. }
  594. /*
  595. * If there's no signal to deliver, we just put the saved sigmask
  596. * back.
  597. */
  598. restore_saved_sigmask();
  599. }
  600. /*
  601. * notification of userspace execution resumption
  602. * - triggered by the TIF_WORK_MASK flags
  603. */
  604. __visible void
  605. do_notify_resume(struct pt_regs *regs, void *unused, __u32 thread_info_flags)
  606. {
  607. user_exit();
  608. if (thread_info_flags & _TIF_UPROBE)
  609. uprobe_notify_resume(regs);
  610. /* deal with pending signal delivery */
  611. if (thread_info_flags & _TIF_SIGPENDING)
  612. do_signal(regs);
  613. if (thread_info_flags & _TIF_NOTIFY_RESUME) {
  614. clear_thread_flag(TIF_NOTIFY_RESUME);
  615. tracehook_notify_resume(regs);
  616. }
  617. if (thread_info_flags & _TIF_USER_RETURN_NOTIFY)
  618. fire_user_return_notifiers();
  619. user_enter();
  620. }
  621. void signal_fault(struct pt_regs *regs, void __user *frame, char *where)
  622. {
  623. struct task_struct *me = current;
  624. if (show_unhandled_signals && printk_ratelimit()) {
  625. printk("%s"
  626. "%s[%d] bad frame in %s frame:%p ip:%lx sp:%lx orax:%lx",
  627. task_pid_nr(current) > 1 ? KERN_INFO : KERN_EMERG,
  628. me->comm, me->pid, where, frame,
  629. regs->ip, regs->sp, regs->orig_ax);
  630. print_vma_addr(" in ", regs->ip);
  631. pr_cont("\n");
  632. }
  633. force_sig(SIGSEGV, me);
  634. }
  635. #ifdef CONFIG_X86_X32_ABI
  636. asmlinkage long sys32_x32_rt_sigreturn(void)
  637. {
  638. struct pt_regs *regs = current_pt_regs();
  639. struct rt_sigframe_x32 __user *frame;
  640. sigset_t set;
  641. frame = (struct rt_sigframe_x32 __user *)(regs->sp - 8);
  642. if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
  643. goto badframe;
  644. if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
  645. goto badframe;
  646. set_current_blocked(&set);
  647. if (restore_sigcontext(regs, &frame->uc.uc_mcontext))
  648. goto badframe;
  649. if (compat_restore_altstack(&frame->uc.uc_stack))
  650. goto badframe;
  651. return regs->ax;
  652. badframe:
  653. signal_fault(regs, frame, "x32 rt_sigreturn");
  654. return 0;
  655. }
  656. #endif