signal.c 14.1 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
 *    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/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>
Martin Schwidefsky's avatar
Martin Schwidefsky committed
27
#include <linux/tracehook.h>
28
#include <linux/syscalls.h>
29
#include <linux/compat.h>
Linus Torvalds's avatar
Linus Torvalds committed
30 31 32
#include <asm/ucontext.h>
#include <asm/uaccess.h>
#include <asm/lowcore.h>
33
#include <asm/switch_to.h>
34
#include "entry.h"
Linus Torvalds's avatar
Linus Torvalds committed
35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58

#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.
 */
59
SYSCALL_DEFINE3(sigsuspend, int, history0, int, history1, old_sigset_t, mask)
Linus Torvalds's avatar
Linus Torvalds committed
60
{
61
	sigset_t blocked;
Linus Torvalds's avatar
Linus Torvalds committed
62

63 64 65 66
	current->saved_sigmask = current->blocked;
	mask &= _BLOCKABLE;
	siginitset(&blocked, mask);
	set_current_blocked(&blocked);
67
	set_current_state(TASK_INTERRUPTIBLE);
68
	schedule();
69
	set_restore_sigmask();
70
	return -ERESTARTNOHAND;
Linus Torvalds's avatar
Linus Torvalds committed
71 72
}

73 74
SYSCALL_DEFINE3(sigaction, int, sig, const struct old_sigaction __user *, act,
		struct old_sigaction __user *, oact)
Linus Torvalds's avatar
Linus Torvalds committed
75 76 77 78 79 80 81 82
{
	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
			return -EFAULT;
	}

	return ret;
}

104 105
SYSCALL_DEFINE2(sigaltstack, const stack_t __user *, uss,
		stack_t __user *, uoss)
Linus Torvalds's avatar
Linus Torvalds committed
106
{
107
	struct pt_regs *regs = task_pt_regs(current);
Linus Torvalds's avatar
Linus Torvalds committed
108 109 110 111 112 113
	return do_sigaltstack(uss, uoss, regs->gprs[15]);
}

/* Returns non-zero on fault. */
static int save_sigregs(struct pt_regs *regs, _sigregs __user *sregs)
{
114 115
	_sigregs user_sregs;

Linus Torvalds's avatar
Linus Torvalds committed
116 117 118 119
	save_access_regs(current->thread.acrs);

	/* Copy a 'clean' PSW mask to the user to avoid leaking
	   information about whether PER is currently on.  */
120 121
	user_sregs.regs.psw.mask = psw_user_bits |
		(regs->psw.mask & PSW_MASK_USER);
122 123
	user_sregs.regs.psw.addr = regs->psw.addr;
	memcpy(&user_sregs.regs.gprs, &regs->gprs, sizeof(sregs->regs.gprs));
124 125
	memcpy(&user_sregs.regs.acrs, current->thread.acrs,
	       sizeof(sregs->regs.acrs));
Linus Torvalds's avatar
Linus Torvalds committed
126 127 128 129 130
	/* 
	 * 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);
131 132 133
	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
134 135 136 137 138 139
}

/* Returns positive number on error */
static int restore_sigregs(struct pt_regs *regs, _sigregs __user *sregs)
{
	int err;
140
	_sigregs user_sregs;
Linus Torvalds's avatar
Linus Torvalds committed
141 142 143 144

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

145
	err = __copy_from_user(&user_sregs, sregs, sizeof(_sigregs));
Linus Torvalds's avatar
Linus Torvalds committed
146 147
	if (err)
		return err;
148
	/* Use regs->psw.mask instead of psw_user_bits to preserve PER bit. */
149
	regs->psw.mask = (regs->psw.mask & ~PSW_MASK_USER) |
150 151 152 153 154
		(user_sregs.regs.psw.mask & PSW_MASK_USER);
	/* Check for invalid amode */
	if (regs->psw.mask & PSW_MASK_EA)
		regs->psw.mask |= PSW_MASK_BA;
	regs->psw.addr = user_sregs.regs.psw.addr;
155
	memcpy(&regs->gprs, &user_sregs.regs.gprs, sizeof(sregs->regs.gprs));
156 157
	memcpy(&current->thread.acrs, &user_sregs.regs.acrs,
	       sizeof(sregs->regs.acrs));
Linus Torvalds's avatar
Linus Torvalds committed
158 159
	restore_access_regs(current->thread.acrs);

160 161
	memcpy(&current->thread.fp_regs, &user_sregs.fpregs,
	       sizeof(s390_fp_regs));
Linus Torvalds's avatar
Linus Torvalds committed
162 163 164
	current->thread.fp_regs.fpc &= FPC_VALID_MASK;

	restore_fp_regs(&current->thread.fp_regs);
165
	clear_thread_flag(TIF_SYSCALL);	/* No longer in a system call */
Linus Torvalds's avatar
Linus Torvalds committed
166 167 168
	return 0;
}

169
SYSCALL_DEFINE0(sigreturn)
Linus Torvalds's avatar
Linus Torvalds committed
170
{
171
	struct pt_regs *regs = task_pt_regs(current);
Linus Torvalds's avatar
Linus Torvalds committed
172 173 174 175 176 177 178 179
	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);
180
	set_current_blocked(&set);
Linus Torvalds's avatar
Linus Torvalds committed
181 182 183 184 185 186 187 188
	if (restore_sigregs(regs, &frame->sregs))
		goto badframe;
	return regs->gprs[2];
badframe:
	force_sig(SIGSEGV, current);
	return 0;
}

189
SYSCALL_DEFINE0(rt_sigreturn)
Linus Torvalds's avatar
Linus Torvalds committed
190
{
191
	struct pt_regs *regs = task_pt_regs(current);
Linus Torvalds's avatar
Linus Torvalds committed
192 193 194 195 196 197 198 199
	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);
200
	set_current_blocked(&set);
Linus Torvalds's avatar
Linus Torvalds committed
201 202
	if (restore_sigregs(regs, &frame->uc.uc_mcontext))
		goto badframe;
203 204 205
	if (do_sigaltstack(&frame->uc.uc_stack, NULL,
			   regs->gprs[15]) == -EFAULT)
		goto badframe;
Linus Torvalds's avatar
Linus Torvalds committed
206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227
	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];

228 229 230 231
	/* Overflow on alternate signal stack gives SIGSEGV. */
	if (on_sig_stack(sp) && !on_sig_stack((sp - frame_size) & -8UL))
		return (void __user *) -1UL;

Linus Torvalds's avatar
Linus Torvalds committed
232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250
	/* 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;
	}

	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;
}

251 252
static int setup_frame(int sig, struct k_sigaction *ka,
		       sigset_t *set, struct pt_regs * regs)
Linus Torvalds's avatar
Linus Torvalds committed
253 254 255 256 257 258 259
{
	sigframe __user *frame;

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

260 261 262
	if (frame == (void __user *) -1UL)
		goto give_sigsegv;

Linus Torvalds's avatar
Linus Torvalds committed
263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289
	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;
290
	regs->psw.mask |= PSW_MASK_EA | PSW_MASK_BA;	/* 64 bit amode */
Linus Torvalds's avatar
Linus Torvalds committed
291 292 293 294 295 296 297
	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. */
298 299 300 301 302 303 304
	if (sig == SIGSEGV || sig == SIGBUS || sig == SIGILL ||
	    sig == SIGTRAP || sig == SIGFPE) {
		/* set extra registers only for synchronous signals */
		regs->gprs[4] = regs->int_code & 127;
		regs->gprs[5] = regs->int_parm_long;
		regs->gprs[6] = task_thread_info(current)->last_break;
	}
Linus Torvalds's avatar
Linus Torvalds committed
305 306 307 308

	/* Place signal number on stack to allow backtrace from handler.  */
	if (__put_user(regs->gprs[2], (int __user *) &frame->signo))
		goto give_sigsegv;
309
	return 0;
Linus Torvalds's avatar
Linus Torvalds committed
310 311 312

give_sigsegv:
	force_sigsegv(sig, current);
313
	return -EFAULT;
Linus Torvalds's avatar
Linus Torvalds committed
314 315
}

316
static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
Linus Torvalds's avatar
Linus Torvalds committed
317 318 319 320 321 322 323 324 325
			   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;

326 327 328
	if (frame == (void __user *) -1UL)
		goto give_sigsegv;

Linus Torvalds's avatar
Linus Torvalds committed
329 330 331 332 333
	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
	}

	/* 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;
363
	regs->psw.mask |= PSW_MASK_EA | PSW_MASK_BA;	/* 64 bit amode */
Linus Torvalds's avatar
Linus Torvalds committed
364 365 366 367 368
	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;
369
	regs->gprs[5] = task_thread_info(current)->last_break;
370
	return 0;
Linus Torvalds's avatar
Linus Torvalds committed
371 372 373

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

377 378 379
static int handle_signal(unsigned long sig, struct k_sigaction *ka,
			 siginfo_t *info, sigset_t *oldset,
			 struct pt_regs *regs)
Linus Torvalds's avatar
Linus Torvalds committed
380
{
381 382
	int ret;

Linus Torvalds's avatar
Linus Torvalds committed
383 384
	/* Set up the stack frame */
	if (ka->sa.sa_flags & SA_SIGINFO)
385
		ret = setup_rt_frame(sig, ka, info, oldset, regs);
Linus Torvalds's avatar
Linus Torvalds committed
386
	else
387
		ret = setup_frame(sig, ka, oldset, regs);
388 389
	if (ret)
		return ret;
Matt Fleming's avatar
Matt Fleming committed
390
	block_sigmask(ka, sig);
391
	return 0;
Linus Torvalds's avatar
Linus Torvalds committed
392 393 394 395 396 397 398 399 400 401 402
}

/*
 * 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.
 */
403
void do_signal(struct pt_regs *regs)
Linus Torvalds's avatar
Linus Torvalds committed
404 405 406 407
{
	siginfo_t info;
	int signr;
	struct k_sigaction ka;
408
	sigset_t *oldset;
Linus Torvalds's avatar
Linus Torvalds committed
409

410 411 412
	if (test_thread_flag(TIF_RESTORE_SIGMASK))
		oldset = &current->saved_sigmask;
	else
Linus Torvalds's avatar
Linus Torvalds committed
413 414
		oldset = &current->blocked;

415 416 417 418 419
	/*
	 * Get signal to deliver. When running under ptrace, at this point
	 * the debugger may change all our registers, including the system
	 * call information.
	 */
420
	current_thread_info()->system_call =
421
		test_thread_flag(TIF_SYSCALL) ? regs->int_code : 0;
Linus Torvalds's avatar
Linus Torvalds committed
422 423 424 425
	signr = get_signal_to_deliver(&info, &ka, regs, NULL);

	if (signr > 0) {
		/* Whee!  Actually deliver the signal.  */
426
		if (current_thread_info()->system_call) {
427
			regs->int_code = current_thread_info()->system_call;
428 429 430 431 432 433 434 435 436 437 438 439 440 441
			/* Check for system call restarting. */
			switch (regs->gprs[2]) {
			case -ERESTART_RESTARTBLOCK:
			case -ERESTARTNOHAND:
				regs->gprs[2] = -EINTR;
				break;
			case -ERESTARTSYS:
				if (!(ka.sa.sa_flags & SA_RESTART)) {
					regs->gprs[2] = -EINTR;
					break;
				}
			/* fallthrough */
			case -ERESTARTNOINTR:
				regs->gprs[2] = regs->orig_gpr2;
442 443
				regs->psw.addr =
					__rewind_psw(regs->psw,
444
						     regs->int_code >> 16);
445 446 447
				break;
			}
		}
448 449
		/* No longer in a system call */
		clear_thread_flag(TIF_SYSCALL);
450 451 452 453

		if ((is_compat_task() ?
		     handle_signal32(signr, &ka, &info, oldset, regs) :
		     handle_signal(signr, &ka, &info, oldset, regs)) == 0) {
454 455 456 457 458 459 460 461
			/*
			 * 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);
Roland McGrath's avatar
Roland McGrath committed
462

Martin Schwidefsky's avatar
Martin Schwidefsky committed
463 464 465 466
			/*
			 * Let tracing know that we've done the handler setup.
			 */
			tracehook_signal_handler(signr, &info, &ka, regs,
467
					 test_thread_flag(TIF_SINGLE_STEP));
468 469 470 471
		}
		return;
	}

472
	/* No handlers present - check for system call restart */
473
	clear_thread_flag(TIF_SYSCALL);
474
	if (current_thread_info()->system_call) {
475
		regs->int_code = current_thread_info()->system_call;
476 477 478
		switch (regs->gprs[2]) {
		case -ERESTART_RESTARTBLOCK:
			/* Restart with sys_restart_syscall */
479
			regs->int_code = __NR_restart_syscall;
480 481 482 483 484 485
		/* fallthrough */
		case -ERESTARTNOHAND:
		case -ERESTARTSYS:
		case -ERESTARTNOINTR:
			/* Restart system call with magic TIF bit. */
			regs->gprs[2] = regs->orig_gpr2;
486 487
			set_thread_flag(TIF_SYSCALL);
			break;
488 489 490
		}
	}

491 492 493 494 495 496
	/*
	 * 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
497 498
	}
}
Martin Schwidefsky's avatar
Martin Schwidefsky committed
499 500 501 502 503

void do_notify_resume(struct pt_regs *regs)
{
	clear_thread_flag(TIF_NOTIFY_RESUME);
	tracehook_notify_resume(regs);
504 505
	if (current->replacement_session_keyring)
		key_replace_session_keyring();
Martin Schwidefsky's avatar
Martin Schwidefsky committed
506
}