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1 /*  linux/arch/sparc/kernel/signal.c
2  *
3  *  Copyright (C) 1991, 1992  Linus Torvalds
4  *  Copyright (C) 1995 David S. Miller (davem@caip.rutgers.edu)
5  *  Copyright (C) 1996 Miguel de Icaza (miguel@nuclecu.unam.mx)
6  *  Copyright (C) 1997 Eddie C. Dost   (ecd@skynet.be)
7  */
8 
9 #include <linux/sched.h>
10 #include <linux/kernel.h>
11 #include <linux/signal.h>
12 #include <linux/errno.h>
13 #include <linux/wait.h>
14 #include <linux/ptrace.h>
15 #include <linux/unistd.h>
16 #include <linux/mm.h>
17 #include <linux/tty.h>
18 #include <linux/smp.h>
19 #include <linux/binfmts.h>	/* do_coredum */
20 #include <linux/bitops.h>
21 #include <linux/tracehook.h>
22 
23 #include <asm/uaccess.h>
24 #include <asm/ptrace.h>
25 #include <asm/pgalloc.h>
26 #include <asm/pgtable.h>
27 #include <asm/cacheflush.h>	/* flush_sig_insns */
28 
29 #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
30 
31 extern void fpsave(unsigned long *fpregs, unsigned long *fsr,
32 		   void *fpqueue, unsigned long *fpqdepth);
33 extern void fpload(unsigned long *fpregs, unsigned long *fsr);
34 
35 struct signal_frame {
36 	struct sparc_stackf	ss;
37 	__siginfo32_t		info;
38 	__siginfo_fpu_t __user	*fpu_save;
39 	unsigned long		insns[2] __attribute__ ((aligned (8)));
40 	unsigned int		extramask[_NSIG_WORDS - 1];
41 	unsigned int		extra_size; /* Should be 0 */
42 	__siginfo_fpu_t		fpu_state;
43 };
44 
45 struct rt_signal_frame {
46 	struct sparc_stackf	ss;
47 	siginfo_t		info;
48 	struct pt_regs		regs;
49 	sigset_t		mask;
50 	__siginfo_fpu_t __user	*fpu_save;
51 	unsigned int		insns[2];
52 	stack_t			stack;
53 	unsigned int		extra_size; /* Should be 0 */
54 	__siginfo_fpu_t		fpu_state;
55 };
56 
57 /* Align macros */
58 #define SF_ALIGNEDSZ  (((sizeof(struct signal_frame) + 7) & (~7)))
59 #define RT_ALIGNEDSZ  (((sizeof(struct rt_signal_frame) + 7) & (~7)))
60 
_sigpause_common(old_sigset_t set)61 static int _sigpause_common(old_sigset_t set)
62 {
63 	set &= _BLOCKABLE;
64 	spin_lock_irq(&current->sighand->siglock);
65 	current->saved_sigmask = current->blocked;
66 	siginitset(&current->blocked, set);
67 	recalc_sigpending();
68 	spin_unlock_irq(&current->sighand->siglock);
69 
70 	current->state = TASK_INTERRUPTIBLE;
71 	schedule();
72 	set_thread_flag(TIF_RESTORE_SIGMASK);
73 
74 	return -ERESTARTNOHAND;
75 }
76 
sys_sigsuspend(old_sigset_t set)77 asmlinkage int sys_sigsuspend(old_sigset_t set)
78 {
79 	return _sigpause_common(set);
80 }
81 
82 static inline int
restore_fpu_state(struct pt_regs * regs,__siginfo_fpu_t __user * fpu)83 restore_fpu_state(struct pt_regs *regs, __siginfo_fpu_t __user *fpu)
84 {
85 	int err;
86 #ifdef CONFIG_SMP
87 	if (test_tsk_thread_flag(current, TIF_USEDFPU))
88 		regs->psr &= ~PSR_EF;
89 #else
90 	if (current == last_task_used_math) {
91 		last_task_used_math = NULL;
92 		regs->psr &= ~PSR_EF;
93 	}
94 #endif
95 	set_used_math();
96 	clear_tsk_thread_flag(current, TIF_USEDFPU);
97 
98 	if (!access_ok(VERIFY_READ, fpu, sizeof(*fpu)))
99 		return -EFAULT;
100 
101 	err = __copy_from_user(&current->thread.float_regs[0], &fpu->si_float_regs[0],
102 			       (sizeof(unsigned long) * 32));
103 	err |= __get_user(current->thread.fsr, &fpu->si_fsr);
104 	err |= __get_user(current->thread.fpqdepth, &fpu->si_fpqdepth);
105 	if (current->thread.fpqdepth != 0)
106 		err |= __copy_from_user(&current->thread.fpqueue[0],
107 					&fpu->si_fpqueue[0],
108 					((sizeof(unsigned long) +
109 					(sizeof(unsigned long *)))*16));
110 	return err;
111 }
112 
do_sigreturn(struct pt_regs * regs)113 asmlinkage void do_sigreturn(struct pt_regs *regs)
114 {
115 	struct signal_frame __user *sf;
116 	unsigned long up_psr, pc, npc;
117 	sigset_t set;
118 	__siginfo_fpu_t __user *fpu_save;
119 	int err;
120 
121 	/* Always make any pending restarted system calls return -EINTR */
122 	current_thread_info()->restart_block.fn = do_no_restart_syscall;
123 
124 	synchronize_user_stack();
125 
126 	sf = (struct signal_frame __user *) regs->u_regs[UREG_FP];
127 
128 	/* 1. Make sure we are not getting garbage from the user */
129 	if (!access_ok(VERIFY_READ, sf, sizeof(*sf)))
130 		goto segv_and_exit;
131 
132 	if (((unsigned long) sf) & 3)
133 		goto segv_and_exit;
134 
135 	err = __get_user(pc,  &sf->info.si_regs.pc);
136 	err |= __get_user(npc, &sf->info.si_regs.npc);
137 
138 	if ((pc | npc) & 3)
139 		goto segv_and_exit;
140 
141 	/* 2. Restore the state */
142 	up_psr = regs->psr;
143 	err |= __copy_from_user(regs, &sf->info.si_regs, sizeof(struct pt_regs));
144 
145 	/* User can only change condition codes and FPU enabling in %psr. */
146 	regs->psr = (up_psr & ~(PSR_ICC | PSR_EF))
147 		  | (regs->psr & (PSR_ICC | PSR_EF));
148 
149 	/* Prevent syscall restart.  */
150 	pt_regs_clear_syscall(regs);
151 
152 	err |= __get_user(fpu_save, &sf->fpu_save);
153 
154 	if (fpu_save)
155 		err |= restore_fpu_state(regs, fpu_save);
156 
157 	/* This is pretty much atomic, no amount locking would prevent
158 	 * the races which exist anyways.
159 	 */
160 	err |= __get_user(set.sig[0], &sf->info.si_mask);
161 	err |= __copy_from_user(&set.sig[1], &sf->extramask,
162 			        (_NSIG_WORDS-1) * sizeof(unsigned int));
163 
164 	if (err)
165 		goto segv_and_exit;
166 
167 	sigdelsetmask(&set, ~_BLOCKABLE);
168 	spin_lock_irq(&current->sighand->siglock);
169 	current->blocked = set;
170 	recalc_sigpending();
171 	spin_unlock_irq(&current->sighand->siglock);
172 	return;
173 
174 segv_and_exit:
175 	force_sig(SIGSEGV, current);
176 }
177 
do_rt_sigreturn(struct pt_regs * regs)178 asmlinkage void do_rt_sigreturn(struct pt_regs *regs)
179 {
180 	struct rt_signal_frame __user *sf;
181 	unsigned int psr, pc, npc;
182 	__siginfo_fpu_t __user *fpu_save;
183 	mm_segment_t old_fs;
184 	sigset_t set;
185 	stack_t st;
186 	int err;
187 
188 	synchronize_user_stack();
189 	sf = (struct rt_signal_frame __user *) regs->u_regs[UREG_FP];
190 	if (!access_ok(VERIFY_READ, sf, sizeof(*sf)) ||
191 	    (((unsigned long) sf) & 0x03))
192 		goto segv;
193 
194 	err = __get_user(pc, &sf->regs.pc);
195 	err |= __get_user(npc, &sf->regs.npc);
196 	err |= ((pc | npc) & 0x03);
197 
198 	err |= __get_user(regs->y, &sf->regs.y);
199 	err |= __get_user(psr, &sf->regs.psr);
200 
201 	err |= __copy_from_user(&regs->u_regs[UREG_G1],
202 				&sf->regs.u_regs[UREG_G1], 15 * sizeof(u32));
203 
204 	regs->psr = (regs->psr & ~PSR_ICC) | (psr & PSR_ICC);
205 
206 	/* Prevent syscall restart.  */
207 	pt_regs_clear_syscall(regs);
208 
209 	err |= __get_user(fpu_save, &sf->fpu_save);
210 
211 	if (fpu_save)
212 		err |= restore_fpu_state(regs, fpu_save);
213 	err |= __copy_from_user(&set, &sf->mask, sizeof(sigset_t));
214 
215 	err |= __copy_from_user(&st, &sf->stack, sizeof(stack_t));
216 
217 	if (err)
218 		goto segv;
219 
220 	regs->pc = pc;
221 	regs->npc = npc;
222 
223 	/* It is more difficult to avoid calling this function than to
224 	 * call it and ignore errors.
225 	 */
226 	old_fs = get_fs();
227 	set_fs(KERNEL_DS);
228 	do_sigaltstack((const stack_t __user *) &st, NULL, (unsigned long)sf);
229 	set_fs(old_fs);
230 
231 	sigdelsetmask(&set, ~_BLOCKABLE);
232 	spin_lock_irq(&current->sighand->siglock);
233 	current->blocked = set;
234 	recalc_sigpending();
235 	spin_unlock_irq(&current->sighand->siglock);
236 	return;
237 segv:
238 	force_sig(SIGSEGV, current);
239 }
240 
241 /* Checks if the fp is valid */
invalid_frame_pointer(void __user * fp,int fplen)242 static inline int invalid_frame_pointer(void __user *fp, int fplen)
243 {
244 	if ((((unsigned long) fp) & 7) ||
245 	    !__access_ok((unsigned long)fp, fplen) ||
246 	    ((sparc_cpu_model == sun4 || sparc_cpu_model == sun4c) &&
247 	     ((unsigned long) fp < 0xe0000000 && (unsigned long) fp >= 0x20000000)))
248 		return 1;
249 
250 	return 0;
251 }
252 
get_sigframe(struct sigaction * sa,struct pt_regs * regs,unsigned long framesize)253 static inline void __user *get_sigframe(struct sigaction *sa, struct pt_regs *regs, unsigned long framesize)
254 {
255 	unsigned long sp = regs->u_regs[UREG_FP];
256 
257 	/*
258 	 * If we are on the alternate signal stack and would overflow it, don't.
259 	 * Return an always-bogus address instead so we will die with SIGSEGV.
260 	 */
261 	if (on_sig_stack(sp) && !likely(on_sig_stack(sp - framesize)))
262 		return (void __user *) -1L;
263 
264 	/* This is the X/Open sanctioned signal stack switching.  */
265 	if (sa->sa_flags & SA_ONSTACK) {
266 		if (sas_ss_flags(sp) == 0)
267 			sp = current->sas_ss_sp + current->sas_ss_size;
268 	}
269 
270 	/* Always align the stack frame.  This handles two cases.  First,
271 	 * sigaltstack need not be mindful of platform specific stack
272 	 * alignment.  Second, if we took this signal because the stack
273 	 * is not aligned properly, we'd like to take the signal cleanly
274 	 * and report that.
275 	 */
276 	sp &= ~7UL;
277 
278 	return (void __user *)(sp - framesize);
279 }
280 
281 static inline int
save_fpu_state(struct pt_regs * regs,__siginfo_fpu_t __user * fpu)282 save_fpu_state(struct pt_regs *regs, __siginfo_fpu_t __user *fpu)
283 {
284 	int err = 0;
285 #ifdef CONFIG_SMP
286 	if (test_tsk_thread_flag(current, TIF_USEDFPU)) {
287 		put_psr(get_psr() | PSR_EF);
288 		fpsave(&current->thread.float_regs[0], &current->thread.fsr,
289 		       &current->thread.fpqueue[0], &current->thread.fpqdepth);
290 		regs->psr &= ~(PSR_EF);
291 		clear_tsk_thread_flag(current, TIF_USEDFPU);
292 	}
293 #else
294 	if (current == last_task_used_math) {
295 		put_psr(get_psr() | PSR_EF);
296 		fpsave(&current->thread.float_regs[0], &current->thread.fsr,
297 		       &current->thread.fpqueue[0], &current->thread.fpqdepth);
298 		last_task_used_math = NULL;
299 		regs->psr &= ~(PSR_EF);
300 	}
301 #endif
302 	err |= __copy_to_user(&fpu->si_float_regs[0],
303 			      &current->thread.float_regs[0],
304 			      (sizeof(unsigned long) * 32));
305 	err |= __put_user(current->thread.fsr, &fpu->si_fsr);
306 	err |= __put_user(current->thread.fpqdepth, &fpu->si_fpqdepth);
307 	if (current->thread.fpqdepth != 0)
308 		err |= __copy_to_user(&fpu->si_fpqueue[0],
309 				      &current->thread.fpqueue[0],
310 				      ((sizeof(unsigned long) +
311 				      (sizeof(unsigned long *)))*16));
312 	clear_used_math();
313 	return err;
314 }
315 
setup_frame(struct k_sigaction * ka,struct pt_regs * regs,int signo,sigset_t * oldset)316 static void setup_frame(struct k_sigaction *ka, struct pt_regs *regs,
317 			int signo, sigset_t *oldset)
318 {
319 	struct signal_frame __user *sf;
320 	int sigframe_size, err;
321 
322 	/* 1. Make sure everything is clean */
323 	synchronize_user_stack();
324 
325 	sigframe_size = SF_ALIGNEDSZ;
326 	if (!used_math())
327 		sigframe_size -= sizeof(__siginfo_fpu_t);
328 
329 	sf = (struct signal_frame __user *)
330 		get_sigframe(&ka->sa, regs, sigframe_size);
331 
332 	if (invalid_frame_pointer(sf, sigframe_size))
333 		goto sigill_and_return;
334 
335 	if (current_thread_info()->w_saved != 0)
336 		goto sigill_and_return;
337 
338 	/* 2. Save the current process state */
339 	err = __copy_to_user(&sf->info.si_regs, regs, sizeof(struct pt_regs));
340 
341 	err |= __put_user(0, &sf->extra_size);
342 
343 	if (used_math()) {
344 		err |= save_fpu_state(regs, &sf->fpu_state);
345 		err |= __put_user(&sf->fpu_state, &sf->fpu_save);
346 	} else {
347 		err |= __put_user(0, &sf->fpu_save);
348 	}
349 
350 	err |= __put_user(oldset->sig[0], &sf->info.si_mask);
351 	err |= __copy_to_user(sf->extramask, &oldset->sig[1],
352 			      (_NSIG_WORDS - 1) * sizeof(unsigned int));
353 	err |= __copy_to_user(sf, (char *) regs->u_regs[UREG_FP],
354 			      sizeof(struct reg_window32));
355 	if (err)
356 		goto sigsegv;
357 
358 	/* 3. signal handler back-trampoline and parameters */
359 	regs->u_regs[UREG_FP] = (unsigned long) sf;
360 	regs->u_regs[UREG_I0] = signo;
361 	regs->u_regs[UREG_I1] = (unsigned long) &sf->info;
362 	regs->u_regs[UREG_I2] = (unsigned long) &sf->info;
363 
364 	/* 4. signal handler */
365 	regs->pc = (unsigned long) ka->sa.sa_handler;
366 	regs->npc = (regs->pc + 4);
367 
368 	/* 5. return to kernel instructions */
369 	if (ka->ka_restorer)
370 		regs->u_regs[UREG_I7] = (unsigned long)ka->ka_restorer;
371 	else {
372 		regs->u_regs[UREG_I7] = (unsigned long)(&(sf->insns[0]) - 2);
373 
374 		/* mov __NR_sigreturn, %g1 */
375 		err |= __put_user(0x821020d8, &sf->insns[0]);
376 
377 		/* t 0x10 */
378 		err |= __put_user(0x91d02010, &sf->insns[1]);
379 		if (err)
380 			goto sigsegv;
381 
382 		/* Flush instruction space. */
383 		flush_sig_insns(current->mm, (unsigned long) &(sf->insns[0]));
384 	}
385 	return;
386 
387 sigill_and_return:
388 	do_exit(SIGILL);
389 sigsegv:
390 	force_sigsegv(signo, current);
391 }
392 
setup_rt_frame(struct k_sigaction * ka,struct pt_regs * regs,int signo,sigset_t * oldset,siginfo_t * info)393 static void setup_rt_frame(struct k_sigaction *ka, struct pt_regs *regs,
394 			   int signo, sigset_t *oldset, siginfo_t *info)
395 {
396 	struct rt_signal_frame __user *sf;
397 	int sigframe_size;
398 	unsigned int psr;
399 	int err;
400 
401 	synchronize_user_stack();
402 	sigframe_size = RT_ALIGNEDSZ;
403 	if (!used_math())
404 		sigframe_size -= sizeof(__siginfo_fpu_t);
405 	sf = (struct rt_signal_frame __user *)
406 		get_sigframe(&ka->sa, regs, sigframe_size);
407 	if (invalid_frame_pointer(sf, sigframe_size))
408 		goto sigill;
409 	if (current_thread_info()->w_saved != 0)
410 		goto sigill;
411 
412 	err  = __put_user(regs->pc, &sf->regs.pc);
413 	err |= __put_user(regs->npc, &sf->regs.npc);
414 	err |= __put_user(regs->y, &sf->regs.y);
415 	psr = regs->psr;
416 	if (used_math())
417 		psr |= PSR_EF;
418 	err |= __put_user(psr, &sf->regs.psr);
419 	err |= __copy_to_user(&sf->regs.u_regs, regs->u_regs, sizeof(regs->u_regs));
420 	err |= __put_user(0, &sf->extra_size);
421 
422 	if (psr & PSR_EF) {
423 		err |= save_fpu_state(regs, &sf->fpu_state);
424 		err |= __put_user(&sf->fpu_state, &sf->fpu_save);
425 	} else {
426 		err |= __put_user(0, &sf->fpu_save);
427 	}
428 	err |= __copy_to_user(&sf->mask, &oldset->sig[0], sizeof(sigset_t));
429 
430 	/* Setup sigaltstack */
431 	err |= __put_user(current->sas_ss_sp, &sf->stack.ss_sp);
432 	err |= __put_user(sas_ss_flags(regs->u_regs[UREG_FP]), &sf->stack.ss_flags);
433 	err |= __put_user(current->sas_ss_size, &sf->stack.ss_size);
434 
435 	err |= __copy_to_user(sf, (char *) regs->u_regs[UREG_FP],
436 			      sizeof(struct reg_window32));
437 
438 	err |= copy_siginfo_to_user(&sf->info, info);
439 
440 	if (err)
441 		goto sigsegv;
442 
443 	regs->u_regs[UREG_FP] = (unsigned long) sf;
444 	regs->u_regs[UREG_I0] = signo;
445 	regs->u_regs[UREG_I1] = (unsigned long) &sf->info;
446 	regs->u_regs[UREG_I2] = (unsigned long) &sf->regs;
447 
448 	regs->pc = (unsigned long) ka->sa.sa_handler;
449 	regs->npc = (regs->pc + 4);
450 
451 	if (ka->ka_restorer)
452 		regs->u_regs[UREG_I7] = (unsigned long)ka->ka_restorer;
453 	else {
454 		regs->u_regs[UREG_I7] = (unsigned long)(&(sf->insns[0]) - 2);
455 
456 		/* mov __NR_sigreturn, %g1 */
457 		err |= __put_user(0x821020d8, &sf->insns[0]);
458 
459 		/* t 0x10 */
460 		err |= __put_user(0x91d02010, &sf->insns[1]);
461 		if (err)
462 			goto sigsegv;
463 
464 		/* Flush instruction space. */
465 		flush_sig_insns(current->mm, (unsigned long) &(sf->insns[0]));
466 	}
467 	return;
468 
469 sigill:
470 	do_exit(SIGILL);
471 sigsegv:
472 	force_sigsegv(signo, current);
473 }
474 
475 static inline void
handle_signal(unsigned long signr,struct k_sigaction * ka,siginfo_t * info,sigset_t * oldset,struct pt_regs * regs)476 handle_signal(unsigned long signr, struct k_sigaction *ka,
477 	      siginfo_t *info, sigset_t *oldset, struct pt_regs *regs)
478 {
479 	if (ka->sa.sa_flags & SA_SIGINFO)
480 		setup_rt_frame(ka, regs, signr, oldset, info);
481 	else
482 		setup_frame(ka, regs, signr, oldset);
483 
484 	spin_lock_irq(&current->sighand->siglock);
485 	sigorsets(&current->blocked,&current->blocked,&ka->sa.sa_mask);
486 	if (!(ka->sa.sa_flags & SA_NOMASK))
487 		sigaddset(&current->blocked, signr);
488 	recalc_sigpending();
489 	spin_unlock_irq(&current->sighand->siglock);
490 }
491 
syscall_restart(unsigned long orig_i0,struct pt_regs * regs,struct sigaction * sa)492 static inline void syscall_restart(unsigned long orig_i0, struct pt_regs *regs,
493 				   struct sigaction *sa)
494 {
495 	switch(regs->u_regs[UREG_I0]) {
496 	case ERESTART_RESTARTBLOCK:
497 	case ERESTARTNOHAND:
498 	no_system_call_restart:
499 		regs->u_regs[UREG_I0] = EINTR;
500 		regs->psr |= PSR_C;
501 		break;
502 	case ERESTARTSYS:
503 		if (!(sa->sa_flags & SA_RESTART))
504 			goto no_system_call_restart;
505 		/* fallthrough */
506 	case ERESTARTNOINTR:
507 		regs->u_regs[UREG_I0] = orig_i0;
508 		regs->pc -= 4;
509 		regs->npc -= 4;
510 	}
511 }
512 
513 /* Note that 'init' is a special process: it doesn't get signals it doesn't
514  * want to handle. Thus you cannot kill init even with a SIGKILL even by
515  * mistake.
516  */
do_signal(struct pt_regs * regs,unsigned long orig_i0)517 static void do_signal(struct pt_regs *regs, unsigned long orig_i0)
518 {
519 	struct k_sigaction ka;
520 	int restart_syscall;
521 	sigset_t *oldset;
522 	siginfo_t info;
523 	int signr;
524 
525 	if (pt_regs_is_syscall(regs) && (regs->psr & PSR_C))
526 		restart_syscall = 1;
527 	else
528 		restart_syscall = 0;
529 
530 	if (test_thread_flag(TIF_RESTORE_SIGMASK))
531 		oldset = &current->saved_sigmask;
532 	else
533 		oldset = &current->blocked;
534 
535 	signr = get_signal_to_deliver(&info, &ka, regs, NULL);
536 
537 	/* If the debugger messes with the program counter, it clears
538 	 * the software "in syscall" bit, directing us to not perform
539 	 * a syscall restart.
540 	 */
541 	if (restart_syscall && !pt_regs_is_syscall(regs))
542 		restart_syscall = 0;
543 
544 	if (signr > 0) {
545 		if (restart_syscall)
546 			syscall_restart(orig_i0, regs, &ka.sa);
547 		handle_signal(signr, &ka, &info, oldset, regs);
548 
549 		/* a signal was successfully delivered; the saved
550 		 * sigmask will have been stored in the signal frame,
551 		 * and will be restored by sigreturn, so we can simply
552 		 * clear the TIF_RESTORE_SIGMASK flag.
553 		 */
554 		if (test_thread_flag(TIF_RESTORE_SIGMASK))
555 			clear_thread_flag(TIF_RESTORE_SIGMASK);
556 
557 		tracehook_signal_handler(signr, &info, &ka, regs, 0);
558 		return;
559 	}
560 	if (restart_syscall &&
561 	    (regs->u_regs[UREG_I0] == ERESTARTNOHAND ||
562 	     regs->u_regs[UREG_I0] == ERESTARTSYS ||
563 	     regs->u_regs[UREG_I0] == ERESTARTNOINTR)) {
564 		/* replay the system call when we are done */
565 		regs->u_regs[UREG_I0] = orig_i0;
566 		regs->pc -= 4;
567 		regs->npc -= 4;
568 	}
569 	if (restart_syscall &&
570 	    regs->u_regs[UREG_I0] == ERESTART_RESTARTBLOCK) {
571 		regs->u_regs[UREG_G1] = __NR_restart_syscall;
572 		regs->pc -= 4;
573 		regs->npc -= 4;
574 	}
575 
576 	/* if there's no signal to deliver, we just put the saved sigmask
577 	 * back
578 	 */
579 	if (test_thread_flag(TIF_RESTORE_SIGMASK)) {
580 		clear_thread_flag(TIF_RESTORE_SIGMASK);
581 		sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
582 	}
583 }
584 
do_notify_resume(struct pt_regs * regs,unsigned long orig_i0,unsigned long thread_info_flags)585 void do_notify_resume(struct pt_regs *regs, unsigned long orig_i0,
586 		      unsigned long thread_info_flags)
587 {
588 	if (thread_info_flags & (_TIF_SIGPENDING | _TIF_RESTORE_SIGMASK))
589 		do_signal(regs, orig_i0);
590 	if (thread_info_flags & _TIF_NOTIFY_RESUME) {
591 		clear_thread_flag(TIF_NOTIFY_RESUME);
592 		tracehook_notify_resume(regs);
593 	}
594 }
595 
596 asmlinkage int
do_sys_sigstack(struct sigstack __user * ssptr,struct sigstack __user * ossptr,unsigned long sp)597 do_sys_sigstack(struct sigstack __user *ssptr, struct sigstack __user *ossptr,
598 		unsigned long sp)
599 {
600 	int ret = -EFAULT;
601 
602 	/* First see if old state is wanted. */
603 	if (ossptr) {
604 		if (put_user(current->sas_ss_sp + current->sas_ss_size,
605 			     &ossptr->the_stack) ||
606 		    __put_user(on_sig_stack(sp), &ossptr->cur_status))
607 			goto out;
608 	}
609 
610 	/* Now see if we want to update the new state. */
611 	if (ssptr) {
612 		char *ss_sp;
613 
614 		if (get_user(ss_sp, &ssptr->the_stack))
615 			goto out;
616 		/* If the current stack was set with sigaltstack, don't
617 		   swap stacks while we are on it.  */
618 		ret = -EPERM;
619 		if (current->sas_ss_sp && on_sig_stack(sp))
620 			goto out;
621 
622 		/* Since we don't know the extent of the stack, and we don't
623 		   track onstack-ness, but rather calculate it, we must
624 		   presume a size.  Ho hum this interface is lossy.  */
625 		current->sas_ss_sp = (unsigned long)ss_sp - SIGSTKSZ;
626 		current->sas_ss_size = SIGSTKSZ;
627 	}
628 	ret = 0;
629 out:
630 	return ret;
631 }
632