signal.c 13.2 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

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.
 */
56
SYSCALL_DEFINE3(sigsuspend, int, history0, int, history1, old_sigset_t, mask)
Linus Torvalds's avatar
Linus Torvalds committed
57
{
58 59
	sigset_t blocked;
	siginitset(&blocked, mask);
Al Viro's avatar
Al Viro committed
60
	return sigsuspend(&blocked);
Linus Torvalds's avatar
Linus Torvalds committed
61 62
}

63 64
SYSCALL_DEFINE3(sigaction, int, sig, const struct old_sigaction __user *, act,
		struct old_sigaction __user *, oact)
Linus Torvalds's avatar
Linus Torvalds committed
65 66 67 68 69 70 71 72
{
	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) ||
73 74 75
		    __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
76 77 78 79 80 81 82 83 84
			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) ||
85 86 87
		    __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
88 89 90 91 92 93
			return -EFAULT;
	}

	return ret;
}

94 95
SYSCALL_DEFINE2(sigaltstack, const stack_t __user *, uss,
		stack_t __user *, uoss)
Linus Torvalds's avatar
Linus Torvalds committed
96
{
97
	struct pt_regs *regs = task_pt_regs(current);
Linus Torvalds's avatar
Linus Torvalds committed
98 99 100 101 102 103
	return do_sigaltstack(uss, uoss, regs->gprs[15]);
}

/* Returns non-zero on fault. */
static int save_sigregs(struct pt_regs *regs, _sigregs __user *sregs)
{
104 105
	_sigregs user_sregs;

Linus Torvalds's avatar
Linus Torvalds committed
106 107 108 109
	save_access_regs(current->thread.acrs);

	/* Copy a 'clean' PSW mask to the user to avoid leaking
	   information about whether PER is currently on.  */
110 111
	user_sregs.regs.psw.mask = psw_user_bits |
		(regs->psw.mask & PSW_MASK_USER);
112 113
	user_sregs.regs.psw.addr = regs->psw.addr;
	memcpy(&user_sregs.regs.gprs, &regs->gprs, sizeof(sregs->regs.gprs));
114 115
	memcpy(&user_sregs.regs.acrs, current->thread.acrs,
	       sizeof(sregs->regs.acrs));
Linus Torvalds's avatar
Linus Torvalds committed
116 117 118 119 120
	/* 
	 * 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);
121 122 123
	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
124 125 126 127 128 129
}

/* Returns positive number on error */
static int restore_sigregs(struct pt_regs *regs, _sigregs __user *sregs)
{
	int err;
130
	_sigregs user_sregs;
Linus Torvalds's avatar
Linus Torvalds committed
131 132 133 134

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

135
	err = __copy_from_user(&user_sregs, sregs, sizeof(_sigregs));
Linus Torvalds's avatar
Linus Torvalds committed
136 137
	if (err)
		return err;
138
	/* Use regs->psw.mask instead of psw_user_bits to preserve PER bit. */
139
	regs->psw.mask = (regs->psw.mask & ~PSW_MASK_USER) |
140 141 142 143 144
		(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;
145
	memcpy(&regs->gprs, &user_sregs.regs.gprs, sizeof(sregs->regs.gprs));
146 147
	memcpy(&current->thread.acrs, &user_sregs.regs.acrs,
	       sizeof(sregs->regs.acrs));
Linus Torvalds's avatar
Linus Torvalds committed
148 149
	restore_access_regs(current->thread.acrs);

150 151
	memcpy(&current->thread.fp_regs, &user_sregs.fpregs,
	       sizeof(s390_fp_regs));
Linus Torvalds's avatar
Linus Torvalds committed
152 153 154
	current->thread.fp_regs.fpc &= FPC_VALID_MASK;

	restore_fp_regs(&current->thread.fp_regs);
155
	clear_thread_flag(TIF_SYSCALL);	/* No longer in a system call */
Linus Torvalds's avatar
Linus Torvalds committed
156 157 158
	return 0;
}

159
SYSCALL_DEFINE0(sigreturn)
Linus Torvalds's avatar
Linus Torvalds committed
160
{
161
	struct pt_regs *regs = task_pt_regs(current);
Linus Torvalds's avatar
Linus Torvalds committed
162 163 164 165 166 167 168
	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;
169
	set_current_blocked(&set);
Linus Torvalds's avatar
Linus Torvalds committed
170 171 172 173 174 175 176 177
	if (restore_sigregs(regs, &frame->sregs))
		goto badframe;
	return regs->gprs[2];
badframe:
	force_sig(SIGSEGV, current);
	return 0;
}

178
SYSCALL_DEFINE0(rt_sigreturn)
Linus Torvalds's avatar
Linus Torvalds committed
179
{
180
	struct pt_regs *regs = task_pt_regs(current);
Linus Torvalds's avatar
Linus Torvalds committed
181 182 183 184 185 186 187
	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;
188
	set_current_blocked(&set);
Linus Torvalds's avatar
Linus Torvalds committed
189 190
	if (restore_sigregs(regs, &frame->uc.uc_mcontext))
		goto badframe;
191 192 193
	if (do_sigaltstack(&frame->uc.uc_stack, NULL,
			   regs->gprs[15]) == -EFAULT)
		goto badframe;
Linus Torvalds's avatar
Linus Torvalds committed
194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215
	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];

216 217 218 219
	/* 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
220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238
	/* 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;
}

239 240
static int setup_frame(int sig, struct k_sigaction *ka,
		       sigset_t *set, struct pt_regs * regs)
Linus Torvalds's avatar
Linus Torvalds committed
241 242 243 244 245 246 247
{
	sigframe __user *frame;

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

248 249 250
	if (frame == (void __user *) -1UL)
		goto give_sigsegv;

Linus Torvalds's avatar
Linus Torvalds committed
251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277
	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;
278
	regs->psw.mask |= PSW_MASK_EA | PSW_MASK_BA;	/* 64 bit amode */
Linus Torvalds's avatar
Linus Torvalds committed
279 280 281 282 283 284 285
	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. */
286 287 288 289 290 291 292
	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
293 294 295 296

	/* Place signal number on stack to allow backtrace from handler.  */
	if (__put_user(regs->gprs[2], (int __user *) &frame->signo))
		goto give_sigsegv;
297
	return 0;
Linus Torvalds's avatar
Linus Torvalds committed
298 299 300

give_sigsegv:
	force_sigsegv(sig, current);
301
	return -EFAULT;
Linus Torvalds's avatar
Linus Torvalds committed
302 303
}

304
static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
Linus Torvalds's avatar
Linus Torvalds committed
305 306 307 308 309 310 311 312 313
			   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;

314 315 316
	if (frame == (void __user *) -1UL)
		goto give_sigsegv;

Linus Torvalds's avatar
Linus Torvalds committed
317 318 319 320 321
	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
322 323
	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
324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339
	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;
340 341 342
		if (__put_user(S390_SYSCALL_OPCODE | __NR_rt_sigreturn,
			       (u16 __user *)(frame->retcode)))
			goto give_sigsegv;
Linus Torvalds's avatar
Linus Torvalds committed
343 344 345 346 347 348 349 350
	}

	/* 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;
351
	regs->psw.mask |= PSW_MASK_EA | PSW_MASK_BA;	/* 64 bit amode */
Linus Torvalds's avatar
Linus Torvalds committed
352 353 354 355 356
	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;
357
	regs->gprs[5] = task_thread_info(current)->last_break;
358
	return 0;
Linus Torvalds's avatar
Linus Torvalds committed
359 360 361

give_sigsegv:
	force_sigsegv(sig, current);
362
	return -EFAULT;
Linus Torvalds's avatar
Linus Torvalds committed
363 364
}

365
static void handle_signal(unsigned long sig, struct k_sigaction *ka,
366 367
			 siginfo_t *info, sigset_t *oldset,
			 struct pt_regs *regs)
Linus Torvalds's avatar
Linus Torvalds committed
368
{
369 370
	int ret;

Linus Torvalds's avatar
Linus Torvalds committed
371 372
	/* Set up the stack frame */
	if (ka->sa.sa_flags & SA_SIGINFO)
373
		ret = setup_rt_frame(sig, ka, info, oldset, regs);
Linus Torvalds's avatar
Linus Torvalds committed
374
	else
375
		ret = setup_frame(sig, ka, oldset, regs);
376
	if (ret)
377
		return;
Matt Fleming's avatar
Matt Fleming committed
378
	block_sigmask(ka, sig);
379 380 381 382 383
	/*
	 * Let tracing know that we've done the handler setup.
	 */
	tracehook_signal_handler(sig, info, ka, regs,
				 test_thread_flag(TIF_SINGLE_STEP));
Linus Torvalds's avatar
Linus Torvalds committed
384 385 386 387 388 389 390 391 392 393 394
}

/*
 * 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.
 */
395
void do_signal(struct pt_regs *regs)
Linus Torvalds's avatar
Linus Torvalds committed
396 397 398 399
{
	siginfo_t info;
	int signr;
	struct k_sigaction ka;
Al Viro's avatar
Al Viro committed
400
	sigset_t *oldset = sigmask_to_save();
Linus Torvalds's avatar
Linus Torvalds committed
401

402 403 404 405 406
	/*
	 * Get signal to deliver. When running under ptrace, at this point
	 * the debugger may change all our registers, including the system
	 * call information.
	 */
407
	current_thread_info()->system_call =
408
		test_thread_flag(TIF_SYSCALL) ? regs->int_code : 0;
Linus Torvalds's avatar
Linus Torvalds committed
409 410 411 412
	signr = get_signal_to_deliver(&info, &ka, regs, NULL);

	if (signr > 0) {
		/* Whee!  Actually deliver the signal.  */
413
		if (current_thread_info()->system_call) {
414
			regs->int_code = current_thread_info()->system_call;
415 416 417 418 419 420 421 422 423 424 425 426 427 428
			/* 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;
429 430
				regs->psw.addr =
					__rewind_psw(regs->psw,
431
						     regs->int_code >> 16);
432 433 434
				break;
			}
		}
435 436
		/* No longer in a system call */
		clear_thread_flag(TIF_SYSCALL);
437

438 439 440 441
		if (is_compat_task())
			handle_signal32(signr, &ka, &info, oldset, regs);
		else
			handle_signal(signr, &ka, &info, oldset, regs);
442 443 444
		return;
	}

445
	/* No handlers present - check for system call restart */
446
	clear_thread_flag(TIF_SYSCALL);
447
	if (current_thread_info()->system_call) {
448
		regs->int_code = current_thread_info()->system_call;
449 450 451
		switch (regs->gprs[2]) {
		case -ERESTART_RESTARTBLOCK:
			/* Restart with sys_restart_syscall */
452
			regs->int_code = __NR_restart_syscall;
453 454 455 456 457 458
		/* fallthrough */
		case -ERESTARTNOHAND:
		case -ERESTARTSYS:
		case -ERESTARTNOINTR:
			/* Restart system call with magic TIF bit. */
			regs->gprs[2] = regs->orig_gpr2;
459 460
			set_thread_flag(TIF_SYSCALL);
			break;
461 462 463
		}
	}

464 465 466
	/*
	 * If there's no signal to deliver, we just put the saved sigmask back.
	 */
Al Viro's avatar
Al Viro committed
467
	restore_saved_sigmask();
Linus Torvalds's avatar
Linus Torvalds committed
468
}
Martin Schwidefsky's avatar
Martin Schwidefsky committed
469 470 471 472 473 474

void do_notify_resume(struct pt_regs *regs)
{
	clear_thread_flag(TIF_NOTIFY_RESUME);
	tracehook_notify_resume(regs);
}