signal.c 13.9 KB
Newer Older
Linus Torvalds's avatar
Linus Torvalds committed
1
2
3
/*
 *  arch/s390/kernel/signal.c
 *
4
 *    Copyright (C) IBM Corp. 1999,2006
Linus Torvalds's avatar
Linus Torvalds committed
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
 *    Author(s): Denis Joseph Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com)
 *
 *    Based on Intel version
 * 
 *  Copyright (C) 1991, 1992  Linus Torvalds
 *
 *  1997-11-28  Modified for POSIX.1b signals by Richard Henderson
 */

#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/smp.h>
#include <linux/smp_lock.h>
#include <linux/kernel.h>
#include <linux/signal.h>
#include <linux/errno.h>
#include <linux/wait.h>
#include <linux/ptrace.h>
#include <linux/unistd.h>
#include <linux/stddef.h>
#include <linux/tty.h>
#include <linux/personality.h>
#include <linux/binfmts.h>
#include <asm/ucontext.h>
#include <asm/uaccess.h>
#include <asm/lowcore.h>

#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))


typedef struct 
{
	__u8 callee_used_stack[__SIGNAL_FRAMESIZE];
	struct sigcontext sc;
	_sigregs sregs;
	int signo;
	__u8 retcode[S390_SYSCALL_SIZE];
} sigframe;

typedef struct 
{
	__u8 callee_used_stack[__SIGNAL_FRAMESIZE];
	__u8 retcode[S390_SYSCALL_SIZE];
	struct siginfo info;
	struct ucontext uc;
} rt_sigframe;

/*
 * Atomically swap in the new signal mask, and wait for a signal.
 */
asmlinkage int
56
sys_sigsuspend(int history0, int history1, old_sigset_t mask)
Linus Torvalds's avatar
Linus Torvalds committed
57
58
59
{
	mask &= _BLOCKABLE;
	spin_lock_irq(&current->sighand->siglock);
60
	current->saved_sigmask = current->blocked;
Linus Torvalds's avatar
Linus Torvalds committed
61
62
63
64
	siginitset(&current->blocked, mask);
	recalc_sigpending();
	spin_unlock_irq(&current->sighand->siglock);

65
66
67
	current->state = TASK_INTERRUPTIBLE;
	schedule();
	set_thread_flag(TIF_RESTORE_SIGMASK);
Linus Torvalds's avatar
Linus Torvalds committed
68

69
	return -ERESTARTNOHAND;
Linus Torvalds's avatar
Linus Torvalds committed
70
71
72
73
74
75
76
77
78
79
80
81
82
}

asmlinkage long
sys_sigaction(int sig, const struct old_sigaction __user *act,
	      struct old_sigaction __user *oact)
{
	struct k_sigaction new_ka, old_ka;
	int ret;

	if (act) {
		old_sigset_t mask;
		if (!access_ok(VERIFY_READ, act, sizeof(*act)) ||
		    __get_user(new_ka.sa.sa_handler, &act->sa_handler) ||
83
84
85
		    __get_user(new_ka.sa.sa_restorer, &act->sa_restorer) ||
		    __get_user(new_ka.sa.sa_flags, &act->sa_flags) ||
		    __get_user(mask, &act->sa_mask))
Linus Torvalds's avatar
Linus Torvalds committed
86
87
88
89
90
91
92
93
94
			return -EFAULT;
		siginitset(&new_ka.sa.sa_mask, mask);
	}

	ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);

	if (!ret && oact) {
		if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) ||
		    __put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||
95
96
97
		    __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer) ||
		    __put_user(old_ka.sa.sa_flags, &oact->sa_flags) ||
		    __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask))
Linus Torvalds's avatar
Linus Torvalds committed
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
			return -EFAULT;
	}

	return ret;
}

asmlinkage long
sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss,
					struct pt_regs *regs)
{
	return do_sigaltstack(uss, uoss, regs->gprs[15]);
}



/* Returns non-zero on fault. */
static int save_sigregs(struct pt_regs *regs, _sigregs __user *sregs)
{
116
117
	_sigregs user_sregs;

Linus Torvalds's avatar
Linus Torvalds committed
118
119
120
121
	save_access_regs(current->thread.acrs);

	/* Copy a 'clean' PSW mask to the user to avoid leaking
	   information about whether PER is currently on.  */
122
123
124
	user_sregs.regs.psw.mask = PSW_MASK_MERGE(PSW_USER_BITS, regs->psw.mask);
	user_sregs.regs.psw.addr = regs->psw.addr;
	memcpy(&user_sregs.regs.gprs, &regs->gprs, sizeof(sregs->regs.gprs));
125
126
	memcpy(&user_sregs.regs.acrs, current->thread.acrs,
	       sizeof(sregs->regs.acrs));
Linus Torvalds's avatar
Linus Torvalds committed
127
128
129
130
131
	/* 
	 * We have to store the fp registers to current->thread.fp_regs
	 * to merge them with the emulated registers.
	 */
	save_fp_regs(&current->thread.fp_regs);
132
133
134
	memcpy(&user_sregs.fpregs, &current->thread.fp_regs,
	       sizeof(s390_fp_regs));
	return __copy_to_user(sregs, &user_sregs, sizeof(_sigregs));
Linus Torvalds's avatar
Linus Torvalds committed
135
136
137
138
139
140
}

/* Returns positive number on error */
static int restore_sigregs(struct pt_regs *regs, _sigregs __user *sregs)
{
	int err;
141
	_sigregs user_sregs;
Linus Torvalds's avatar
Linus Torvalds committed
142
143
144
145

	/* Alwys make any pending restarted system call return -EINTR */
	current_thread_info()->restart_block.fn = do_no_restart_syscall;

146
	err = __copy_from_user(&user_sregs, sregs, sizeof(_sigregs));
Linus Torvalds's avatar
Linus Torvalds committed
147
148
	if (err)
		return err;
149
150
151
152
	regs->psw.mask = PSW_MASK_MERGE(regs->psw.mask,
					user_sregs.regs.psw.mask);
	regs->psw.addr = PSW_ADDR_AMODE | user_sregs.regs.psw.addr;
	memcpy(&regs->gprs, &user_sregs.regs.gprs, sizeof(sregs->regs.gprs));
153
154
	memcpy(&current->thread.acrs, &user_sregs.regs.acrs,
	       sizeof(sregs->regs.acrs));
Linus Torvalds's avatar
Linus Torvalds committed
155
156
	restore_access_regs(current->thread.acrs);

157
158
	memcpy(&current->thread.fp_regs, &user_sregs.fpregs,
	       sizeof(s390_fp_regs));
Linus Torvalds's avatar
Linus Torvalds committed
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
	current->thread.fp_regs.fpc &= FPC_VALID_MASK;

	restore_fp_regs(&current->thread.fp_regs);
	regs->trap = -1;	/* disable syscall checks */
	return 0;
}

asmlinkage long sys_sigreturn(struct pt_regs *regs)
{
	sigframe __user *frame = (sigframe __user *)regs->gprs[15];
	sigset_t set;

	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
		goto badframe;
	if (__copy_from_user(&set.sig, &frame->sc.oldmask, _SIGMASK_COPY_SIZE))
		goto badframe;

	sigdelsetmask(&set, ~_BLOCKABLE);
	spin_lock_irq(&current->sighand->siglock);
	current->blocked = set;
	recalc_sigpending();
	spin_unlock_irq(&current->sighand->siglock);

	if (restore_sigregs(regs, &frame->sregs))
		goto badframe;

	return regs->gprs[2];

badframe:
	force_sig(SIGSEGV, current);
	return 0;
}

asmlinkage long sys_rt_sigreturn(struct pt_regs *regs)
{
	rt_sigframe __user *frame = (rt_sigframe __user *)regs->gprs[15];
	sigset_t set;

	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
		goto badframe;
	if (__copy_from_user(&set.sig, &frame->uc.uc_sigmask, sizeof(set)))
		goto badframe;

	sigdelsetmask(&set, ~_BLOCKABLE);
	spin_lock_irq(&current->sighand->siglock);
	current->blocked = set;
	recalc_sigpending();
	spin_unlock_irq(&current->sighand->siglock);

	if (restore_sigregs(regs, &frame->uc.uc_mcontext))
		goto badframe;

211
212
213
	if (do_sigaltstack(&frame->uc.uc_stack, NULL,
			   regs->gprs[15]) == -EFAULT)
		goto badframe;
Linus Torvalds's avatar
Linus Torvalds committed
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
	return regs->gprs[2];

badframe:
	force_sig(SIGSEGV, current);
	return 0;
}

/*
 * Set up a signal frame.
 */


/*
 * Determine which stack to use..
 */
static inline void __user *
get_sigframe(struct k_sigaction *ka, struct pt_regs * regs, size_t frame_size)
{
	unsigned long sp;

	/* Default to using normal stack */
	sp = regs->gprs[15];

	/* This is the X/Open sanctioned signal stack switching.  */
	if (ka->sa.sa_flags & SA_ONSTACK) {
		if (! sas_ss_flags(sp))
			sp = current->sas_ss_sp + current->sas_ss_size;
	}

	/* This is the legacy signal stack switching. */
	else if (!user_mode(regs) &&
		 !(ka->sa.sa_flags & SA_RESTORER) &&
		 ka->sa.sa_restorer) {
		sp = (unsigned long) ka->sa.sa_restorer;
	}

	return (void __user *)((sp - frame_size) & -8ul);
}

static inline int map_signal(int sig)
{
	if (current_thread_info()->exec_domain
	    && current_thread_info()->exec_domain->signal_invmap
	    && sig < 32)
		return current_thread_info()->exec_domain->signal_invmap[sig];
	else
		return sig;
}

263
264
static int setup_frame(int sig, struct k_sigaction *ka,
		       sigset_t *set, struct pt_regs * regs)
Linus Torvalds's avatar
Linus Torvalds committed
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
{
	sigframe __user *frame;

	frame = get_sigframe(ka, regs, sizeof(sigframe));
	if (!access_ok(VERIFY_WRITE, frame, sizeof(sigframe)))
		goto give_sigsegv;

	if (__copy_to_user(&frame->sc.oldmask, &set->sig, _SIGMASK_COPY_SIZE))
		goto give_sigsegv;

	if (save_sigregs(regs, &frame->sregs))
		goto give_sigsegv;
	if (__put_user(&frame->sregs, &frame->sc.sregs))
		goto give_sigsegv;

	/* Set up to return from userspace.  If provided, use a stub
	   already in userspace.  */
	if (ka->sa.sa_flags & SA_RESTORER) {
                regs->gprs[14] = (unsigned long)
			ka->sa.sa_restorer | PSW_ADDR_AMODE;
	} else {
                regs->gprs[14] = (unsigned long)
			frame->retcode | PSW_ADDR_AMODE;
		if (__put_user(S390_SYSCALL_OPCODE | __NR_sigreturn,
	                       (u16 __user *)(frame->retcode)))
			goto give_sigsegv;
	}

	/* Set up backchain. */
	if (__put_user(regs->gprs[15], (addr_t __user *) frame))
		goto give_sigsegv;

	/* Set up registers for signal handler */
	regs->gprs[15] = (unsigned long) frame;
	regs->psw.addr = (unsigned long) ka->sa.sa_handler | PSW_ADDR_AMODE;

	regs->gprs[2] = map_signal(sig);
	regs->gprs[3] = (unsigned long) &frame->sc;

	/* We forgot to include these in the sigcontext.
	   To avoid breaking binary compatibility, they are passed as args. */
	regs->gprs[4] = current->thread.trap_no;
	regs->gprs[5] = current->thread.prot_addr;

	/* Place signal number on stack to allow backtrace from handler.  */
	if (__put_user(regs->gprs[2], (int __user *) &frame->signo))
		goto give_sigsegv;
312
	return 0;
Linus Torvalds's avatar
Linus Torvalds committed
313
314
315

give_sigsegv:
	force_sigsegv(sig, current);
316
	return -EFAULT;
Linus Torvalds's avatar
Linus Torvalds committed
317
318
}

319
static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
Linus Torvalds's avatar
Linus Torvalds committed
320
321
322
323
324
325
326
327
328
329
330
331
332
333
			   sigset_t *set, struct pt_regs * regs)
{
	int err = 0;
	rt_sigframe __user *frame;

	frame = get_sigframe(ka, regs, sizeof(rt_sigframe));
	if (!access_ok(VERIFY_WRITE, frame, sizeof(rt_sigframe)))
		goto give_sigsegv;

	if (copy_siginfo_to_user(&frame->info, info))
		goto give_sigsegv;

	/* Create the ucontext.  */
	err |= __put_user(0, &frame->uc.uc_flags);
Al Viro's avatar
Al Viro committed
334
335
	err |= __put_user(NULL, &frame->uc.uc_link);
	err |= __put_user((void __user *)current->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
Linus Torvalds's avatar
Linus Torvalds committed
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
	err |= __put_user(sas_ss_flags(regs->gprs[15]),
			  &frame->uc.uc_stack.ss_flags);
	err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
	err |= save_sigregs(regs, &frame->uc.uc_mcontext);
	err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
	if (err)
		goto give_sigsegv;

	/* Set up to return from userspace.  If provided, use a stub
	   already in userspace.  */
	if (ka->sa.sa_flags & SA_RESTORER) {
                regs->gprs[14] = (unsigned long)
			ka->sa.sa_restorer | PSW_ADDR_AMODE;
	} else {
                regs->gprs[14] = (unsigned long)
			frame->retcode | PSW_ADDR_AMODE;
352
353
354
		if (__put_user(S390_SYSCALL_OPCODE | __NR_rt_sigreturn,
			       (u16 __user *)(frame->retcode)))
			goto give_sigsegv;
Linus Torvalds's avatar
Linus Torvalds committed
355
356
357
358
359
360
361
362
363
364
365
366
367
	}

	/* Set up backchain. */
	if (__put_user(regs->gprs[15], (addr_t __user *) frame))
		goto give_sigsegv;

	/* Set up registers for signal handler */
	regs->gprs[15] = (unsigned long) frame;
	regs->psw.addr = (unsigned long) ka->sa.sa_handler | PSW_ADDR_AMODE;

	regs->gprs[2] = map_signal(sig);
	regs->gprs[3] = (unsigned long) &frame->info;
	regs->gprs[4] = (unsigned long) &frame->uc;
368
	return 0;
Linus Torvalds's avatar
Linus Torvalds committed
369
370
371

give_sigsegv:
	force_sigsegv(sig, current);
372
	return -EFAULT;
Linus Torvalds's avatar
Linus Torvalds committed
373
374
375
376
377
378
}

/*
 * OK, we're invoking a handler
 */	

379
static int
Linus Torvalds's avatar
Linus Torvalds committed
380
381
382
handle_signal(unsigned long sig, struct k_sigaction *ka,
	      siginfo_t *info, sigset_t *oldset, struct pt_regs * regs)
{
383
384
	int ret;

Linus Torvalds's avatar
Linus Torvalds committed
385
386
	/* Set up the stack frame */
	if (ka->sa.sa_flags & SA_SIGINFO)
387
		ret = setup_rt_frame(sig, ka, info, oldset, regs);
Linus Torvalds's avatar
Linus Torvalds committed
388
	else
389
390
391
392
393
394
395
396
397
398
		ret = setup_frame(sig, ka, oldset, regs);

	if (ret == 0) {
		spin_lock_irq(&current->sighand->siglock);
		sigorsets(&current->blocked,&current->blocked,&ka->sa.sa_mask);
		if (!(ka->sa.sa_flags & SA_NODEFER))
			sigaddset(&current->blocked,sig);
		recalc_sigpending();
		spin_unlock_irq(&current->sighand->siglock);
	}
Linus Torvalds's avatar
Linus Torvalds committed
399

400
	return ret;
Linus Torvalds's avatar
Linus Torvalds committed
401
402
403
404
405
406
407
408
409
410
411
}

/*
 * Note that 'init' is a special process: it doesn't get signals it doesn't
 * want to handle. Thus you cannot kill init even with a SIGKILL even by
 * mistake.
 *
 * Note that we go through the signals twice: once to check the signals that
 * the kernel can handle, and then we build all the user-level signal handling
 * stack-frames in one go after that.
 */
412
void do_signal(struct pt_regs *regs)
Linus Torvalds's avatar
Linus Torvalds committed
413
414
415
416
417
{
	unsigned long retval = 0, continue_addr = 0, restart_addr = 0;
	siginfo_t info;
	int signr;
	struct k_sigaction ka;
418
	sigset_t *oldset;
Linus Torvalds's avatar
Linus Torvalds committed
419
420
421
422
423
424
425
426

	/*
	 * We want the common case to go fast, which
	 * is why we may in certain cases get here from
	 * kernel mode. Just return without doing anything
	 * if so.
	 */
	if (!user_mode(regs))
427
		return;
Linus Torvalds's avatar
Linus Torvalds committed
428

429
430
431
	if (test_thread_flag(TIF_RESTORE_SIGMASK))
		oldset = &current->saved_sigmask;
	else
Linus Torvalds's avatar
Linus Torvalds committed
432
433
434
435
436
437
438
439
440
441
		oldset = &current->blocked;

	/* Are we from a system call? */
	if (regs->trap == __LC_SVC_OLD_PSW) {
		continue_addr = regs->psw.addr;
		restart_addr = continue_addr - regs->ilc;
		retval = regs->gprs[2];

		/* Prepare for system call restart.  We do this here so that a
		   debugger will see the already changed PSW. */
442
443
444
445
		switch (retval) {
		case -ERESTARTNOHAND:
		case -ERESTARTSYS:
		case -ERESTARTNOINTR:
Linus Torvalds's avatar
Linus Torvalds committed
446
447
			regs->gprs[2] = regs->orig_gpr2;
			regs->psw.addr = restart_addr;
448
449
			break;
		case -ERESTART_RESTARTBLOCK:
Linus Torvalds's avatar
Linus Torvalds committed
450
451
			regs->gprs[2] = -EINTR;
		}
452
		regs->trap = -1;	/* Don't deal with this again. */
Linus Torvalds's avatar
Linus Torvalds committed
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
	}

	/* Get signal to deliver.  When running under ptrace, at this point
	   the debugger may change all our registers ... */
	signr = get_signal_to_deliver(&info, &ka, regs, NULL);

	/* Depending on the signal settings we may need to revert the
	   decision to restart the system call. */
	if (signr > 0 && regs->psw.addr == restart_addr) {
		if (retval == -ERESTARTNOHAND
		    || (retval == -ERESTARTSYS
			 && !(current->sighand->action[signr-1].sa.sa_flags
			      & SA_RESTART))) {
			regs->gprs[2] = -EINTR;
			regs->psw.addr = continue_addr;
		}
	}

	if (signr > 0) {
		/* Whee!  Actually deliver the signal.  */
473
#ifdef CONFIG_COMPAT
Linus Torvalds's avatar
Linus Torvalds committed
474
		if (test_thread_flag(TIF_31BIT)) {
475
476
477
478
479
480
481
482
483
484
485
			extern int handle_signal32(unsigned long sig,
						   struct k_sigaction *ka,
						   siginfo_t *info,
						   sigset_t *oldset,
						   struct pt_regs *regs);
			if (handle_signal32(
				    signr, &ka, &info, oldset, regs) == 0) {
				if (test_thread_flag(TIF_RESTORE_SIGMASK))
					clear_thread_flag(TIF_RESTORE_SIGMASK);
			}
			return;
Linus Torvalds's avatar
Linus Torvalds committed
486
487
	        }
#endif
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
		if (handle_signal(signr, &ka, &info, oldset, regs) == 0) {
			/*
			 * A signal was successfully delivered; the saved
			 * sigmask will have been stored in the signal frame,
			 * and will be restored by sigreturn, so we can simply
			 * clear the TIF_RESTORE_SIGMASK flag.
			 */
			if (test_thread_flag(TIF_RESTORE_SIGMASK))
				clear_thread_flag(TIF_RESTORE_SIGMASK);
		}
		return;
	}

	/*
	 * If there's no signal to deliver, we just put the saved sigmask back.
	 */
	if (test_thread_flag(TIF_RESTORE_SIGMASK)) {
		clear_thread_flag(TIF_RESTORE_SIGMASK);
		sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
Linus Torvalds's avatar
Linus Torvalds committed
507
508
509
510
511
512
513
514
515
	}

	/* Restart a different system call. */
	if (retval == -ERESTART_RESTARTBLOCK
	    && regs->psw.addr == continue_addr) {
		regs->gprs[2] = __NR_restart_syscall;
		set_thread_flag(TIF_RESTART_SVC);
	}
}