1/*
2 * arch/v850/kernel/signal.c -- Signal handling
3 *
4 *  Copyright (C) 2001,02,03  NEC Electronics Corporation
5 *  Copyright (C) 2001,02,03  Miles Bader <miles@gnu.org>
6 *  Copyright (C) 1999,2000,2002  Niibe Yutaka & Kaz Kojima
7 *  Copyright (C) 1991,1992  Linus Torvalds
8 *
9 * This file is subject to the terms and conditions of the GNU General
10 * Public License.  See the file COPYING in the main directory of this
11 * archive for more details.
12 *
13 * 1997-11-28  Modified for POSIX.1b signals by Richard Henderson
14 *
15 * This file was derived from the sh version, arch/sh/kernel/signal.c
16 */
17
18#include <linux/mm.h>
19#include <linux/smp.h>
20#include <linux/kernel.h>
21#include <linux/signal.h>
22#include <linux/errno.h>
23#include <linux/wait.h>
24#include <linux/ptrace.h>
25#include <linux/unistd.h>
26#include <linux/stddef.h>
27#include <linux/personality.h>
28#include <linux/tty.h>
29
30#include <asm/ucontext.h>
31#include <asm/uaccess.h>
32#include <asm/pgtable.h>
33#include <asm/pgalloc.h>
34#include <asm/thread_info.h>
35#include <asm/cacheflush.h>
36
37#define DEBUG_SIG 0
38
39#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
40
41asmlinkage int do_signal(struct pt_regs *regs, sigset_t *oldset);
42
43/*
44 * Atomically swap in the new signal mask, and wait for a signal.
45 */
46asmlinkage int
47sys_sigsuspend(old_sigset_t mask, struct pt_regs *regs)
48{
49	sigset_t saveset;
50
51	mask &= _BLOCKABLE;
52	spin_lock_irq(&current->sighand->siglock);
53	saveset = current->blocked;
54	siginitset(&current->blocked, mask);
55	recalc_sigpending();
56	spin_unlock_irq(&current->sighand->siglock);
57
58	regs->gpr[GPR_RVAL] = -EINTR;
59	while (1) {
60		current->state = TASK_INTERRUPTIBLE;
61		schedule();
62		if (do_signal(regs, &saveset))
63			return -EINTR;
64	}
65}
66
67asmlinkage int
68sys_rt_sigsuspend(sigset_t *unewset, size_t sigsetsize,
69		  struct pt_regs *regs)
70{
71	sigset_t saveset, newset;
72
73	if (sigsetsize != sizeof(sigset_t))
74		return -EINVAL;
75
76	if (copy_from_user(&newset, unewset, sizeof(newset)))
77		return -EFAULT;
78	sigdelsetmask(&newset, ~_BLOCKABLE);
79	spin_lock_irq(&current->sighand->siglock);
80	saveset = current->blocked;
81	current->blocked = newset;
82	recalc_sigpending();
83	spin_unlock_irq(&current->sighand->siglock);
84
85	regs->gpr[GPR_RVAL] = -EINTR;
86	while (1) {
87		current->state = TASK_INTERRUPTIBLE;
88		schedule();
89		if (do_signal(regs, &saveset))
90			return -EINTR;
91	}
92}
93
94asmlinkage int
95sys_sigaction(int sig, const struct old_sigaction *act,
96	      struct old_sigaction *oact)
97{
98	struct k_sigaction new_ka, old_ka;
99	int ret;
100
101	if (act) {
102		old_sigset_t mask;
103		if (!access_ok(VERIFY_READ, act, sizeof(*act)) ||
104		    __get_user(new_ka.sa.sa_handler, &act->sa_handler) ||
105		    __get_user(new_ka.sa.sa_restorer, &act->sa_restorer))
106			return -EFAULT;
107		__get_user(new_ka.sa.sa_flags, &act->sa_flags);
108		__get_user(mask, &act->sa_mask);
109		siginitset(&new_ka.sa.sa_mask, mask);
110	}
111
112	ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
113
114	if (!ret && oact) {
115		if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) ||
116		    __put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||
117		    __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer))
118			return -EFAULT;
119		__put_user(old_ka.sa.sa_flags, &oact->sa_flags);
120		__put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask);
121	}
122
123	return ret;
124}
125
126asmlinkage int
127sys_sigaltstack(const stack_t *uss, stack_t *uoss,
128		struct pt_regs *regs)
129{
130	return do_sigaltstack(uss, uoss, regs->gpr[GPR_SP]);
131}
132
133
134/*
135 * Do a signal return; undo the signal stack.
136 */
137
138struct sigframe
139{
140	struct sigcontext sc;
141	unsigned long extramask[_NSIG_WORDS-1];
142	unsigned long tramp[2];	/* signal trampoline */
143};
144
145struct rt_sigframe
146{
147	struct siginfo info;
148	struct ucontext uc;
149	unsigned long tramp[2];	/* signal trampoline */
150};
151
152static int
153restore_sigcontext(struct pt_regs *regs, struct sigcontext *sc, int *rval_p)
154{
155	unsigned int err = 0;
156
157#define COPY(x)		err |= __get_user(regs->x, &sc->regs.x)
158	COPY(gpr[0]);	COPY(gpr[1]);	COPY(gpr[2]);	COPY(gpr[3]);
159	COPY(gpr[4]);	COPY(gpr[5]);	COPY(gpr[6]);	COPY(gpr[7]);
160	COPY(gpr[8]);	COPY(gpr[9]);	COPY(gpr[10]);	COPY(gpr[11]);
161	COPY(gpr[12]);	COPY(gpr[13]);	COPY(gpr[14]);	COPY(gpr[15]);
162	COPY(gpr[16]);	COPY(gpr[17]);	COPY(gpr[18]);	COPY(gpr[19]);
163	COPY(gpr[20]);	COPY(gpr[21]);	COPY(gpr[22]);	COPY(gpr[23]);
164	COPY(gpr[24]);	COPY(gpr[25]);	COPY(gpr[26]);	COPY(gpr[27]);
165	COPY(gpr[28]);	COPY(gpr[29]);	COPY(gpr[30]);	COPY(gpr[31]);
166	COPY(pc);	COPY(psw);
167	COPY(ctpc);	COPY(ctpsw);	COPY(ctbp);
168#undef COPY
169
170	return err;
171}
172
173asmlinkage int sys_sigreturn(struct pt_regs *regs)
174{
175	struct sigframe *frame = (struct sigframe *)regs->gpr[GPR_SP];
176	sigset_t set;
177	int rval;
178
179	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
180		goto badframe;
181
182	if (__get_user(set.sig[0], &frame->sc.oldmask)
183	    || (_NSIG_WORDS > 1
184		&& __copy_from_user(&set.sig[1], &frame->extramask,
185				    sizeof(frame->extramask))))
186		goto badframe;
187
188	sigdelsetmask(&set, ~_BLOCKABLE);
189	spin_lock_irq(&current->sighand->siglock);
190	current->blocked = set;
191	recalc_sigpending();
192	spin_unlock_irq(&current->sighand->siglock);
193
194	if (restore_sigcontext(regs, &frame->sc, &rval))
195		goto badframe;
196	return rval;
197
198badframe:
199	force_sig(SIGSEGV, current);
200	return 0;
201}
202
203asmlinkage int sys_rt_sigreturn(struct pt_regs *regs)
204{
205	struct rt_sigframe *frame = (struct rt_sigframe *)regs->gpr[GPR_SP];
206	sigset_t set;
207	stack_t st;
208	int rval;
209
210	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
211		goto badframe;
212
213	if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
214		goto badframe;
215
216	sigdelsetmask(&set, ~_BLOCKABLE);
217	spin_lock_irq(&current->sighand->siglock);
218	current->blocked = set;
219	recalc_sigpending();
220	spin_unlock_irq(&current->sighand->siglock);
221
222	if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &rval))
223		goto badframe;
224
225	if (__copy_from_user(&st, &frame->uc.uc_stack, sizeof(st)))
226		goto badframe;
227	/* It is more difficult to avoid calling this function than to
228	   call it and ignore errors.  */
229	do_sigaltstack(&st, NULL, regs->gpr[GPR_SP]);
230
231	return rval;
232
233badframe:
234	force_sig(SIGSEGV, current);
235	return 0;
236}
237
238/*
239 * Set up a signal frame.
240 */
241
242static int
243setup_sigcontext(struct sigcontext *sc, struct pt_regs *regs,
244		 unsigned long mask)
245{
246	int err = 0;
247
248#define COPY(x)		err |= __put_user(regs->x, &sc->regs.x)
249	COPY(gpr[0]);	COPY(gpr[1]);	COPY(gpr[2]);	COPY(gpr[3]);
250	COPY(gpr[4]);	COPY(gpr[5]);	COPY(gpr[6]);	COPY(gpr[7]);
251	COPY(gpr[8]);	COPY(gpr[9]);	COPY(gpr[10]);	COPY(gpr[11]);
252	COPY(gpr[12]);	COPY(gpr[13]);	COPY(gpr[14]);	COPY(gpr[15]);
253	COPY(gpr[16]);	COPY(gpr[17]);	COPY(gpr[18]);	COPY(gpr[19]);
254	COPY(gpr[20]);	COPY(gpr[21]);	COPY(gpr[22]);	COPY(gpr[23]);
255	COPY(gpr[24]);	COPY(gpr[25]);	COPY(gpr[26]);	COPY(gpr[27]);
256	COPY(gpr[28]);	COPY(gpr[29]);	COPY(gpr[30]);	COPY(gpr[31]);
257	COPY(pc);	COPY(psw);
258	COPY(ctpc);	COPY(ctpsw);	COPY(ctbp);
259#undef COPY
260
261	err |= __put_user(mask, &sc->oldmask);
262
263	return err;
264}
265
266/*
267 * Determine which stack to use..
268 */
269static inline void *
270get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size)
271{
272	/* Default to using normal stack */
273	unsigned long sp = regs->gpr[GPR_SP];
274
275	if ((ka->sa.sa_flags & SA_ONSTACK) != 0 && ! sas_ss_flags(sp))
276		sp = current->sas_ss_sp + current->sas_ss_size;
277
278	return (void *)((sp - frame_size) & -8UL);
279}
280
281static void setup_frame(int sig, struct k_sigaction *ka,
282			sigset_t *set, struct pt_regs *regs)
283{
284	struct sigframe *frame;
285	int err = 0;
286	int signal;
287
288	frame = get_sigframe(ka, regs, sizeof(*frame));
289
290	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
291		goto give_sigsegv;
292
293	signal = current_thread_info()->exec_domain
294		&& current_thread_info()->exec_domain->signal_invmap
295		&& sig < 32
296		? current_thread_info()->exec_domain->signal_invmap[sig]
297		: sig;
298
299	err |= setup_sigcontext(&frame->sc, regs, set->sig[0]);
300
301	if (_NSIG_WORDS > 1) {
302		err |= __copy_to_user(frame->extramask, &set->sig[1],
303				      sizeof(frame->extramask));
304	}
305
306	/* Set up to return from userspace.  If provided, use a stub
307	   already in userspace.  */
308	if (ka->sa.sa_flags & SA_RESTORER) {
309		regs->gpr[GPR_LP] = (unsigned long) ka->sa.sa_restorer;
310	} else {
311		/* Note, these encodings are _little endian_!  */
312
313		/* addi  __NR_sigreturn, r0, r12  */
314		err |= __put_user(0x6600 | (__NR_sigreturn << 16),
315				  frame->tramp + 0);
316		/* trap 0 */
317		err |= __put_user(0x010007e0,
318				  frame->tramp + 1);
319
320		regs->gpr[GPR_LP] = (unsigned long)frame->tramp;
321
322		flush_cache_sigtramp (regs->gpr[GPR_LP]);
323	}
324
325	if (err)
326		goto give_sigsegv;
327
328	/* Set up registers for signal handler.  */
329	regs->pc = (v850_reg_t) ka->sa.sa_handler;
330	regs->gpr[GPR_SP] = (v850_reg_t)frame;
331	/* Signal handler args:  */
332	regs->gpr[GPR_ARG0] = signal; /* arg 0: signum */
333	regs->gpr[GPR_ARG1] = (v850_reg_t)&frame->sc;/* arg 1: sigcontext */
334
335	set_fs(USER_DS);
336
337#if DEBUG_SIG
338	printk("SIG deliver (%s:%d): sp=%p pc=%08lx ra=%08lx\n",
339		current->comm, current->pid, frame, regs->pc, );
340#endif
341
342	return;
343
344give_sigsegv:
345	force_sigsegv(sig, current);
346}
347
348static void setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
349			   sigset_t *set, struct pt_regs *regs)
350{
351	struct rt_sigframe *frame;
352	int err = 0;
353	int signal;
354
355	frame = get_sigframe(ka, regs, sizeof(*frame));
356
357	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
358		goto give_sigsegv;
359
360	signal = current_thread_info()->exec_domain
361		&& current_thread_info()->exec_domain->signal_invmap
362		&& sig < 32
363		? current_thread_info()->exec_domain->signal_invmap[sig]
364		: sig;
365
366	err |= copy_siginfo_to_user(&frame->info, info);
367
368	/* Create the ucontext.  */
369	err |= __put_user(0, &frame->uc.uc_flags);
370	err |= __put_user(0, &frame->uc.uc_link);
371	err |= __put_user((void *)current->sas_ss_sp,
372			  &frame->uc.uc_stack.ss_sp);
373	err |= __put_user(sas_ss_flags(regs->gpr[GPR_SP]),
374			  &frame->uc.uc_stack.ss_flags);
375	err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
376	err |= setup_sigcontext(&frame->uc.uc_mcontext,
377			        regs, set->sig[0]);
378	err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
379
380	/* Set up to return from userspace.  If provided, use a stub
381	   already in userspace.  */
382	if (ka->sa.sa_flags & SA_RESTORER) {
383		regs->gpr[GPR_LP] = (unsigned long) ka->sa.sa_restorer;
384	} else {
385		/* Note, these encodings are _little endian_!  */
386
387		/* addi  __NR_sigreturn, r0, r12  */
388		err |= __put_user(0x6600 | (__NR_sigreturn << 16),
389				  frame->tramp + 0);
390		/* trap 0 */
391		err |= __put_user(0x010007e0,
392				  frame->tramp + 1);
393
394		regs->gpr[GPR_LP] = (unsigned long)frame->tramp;
395
396		flush_cache_sigtramp (regs->gpr[GPR_LP]);
397	}
398
399	if (err)
400		goto give_sigsegv;
401
402	/* Set up registers for signal handler.  */
403	regs->pc = (v850_reg_t) ka->sa.sa_handler;
404	regs->gpr[GPR_SP] = (v850_reg_t)frame;
405	/* Signal handler args:  */
406	regs->gpr[GPR_ARG0] = signal; /* arg 0: signum */
407	regs->gpr[GPR_ARG1] = (v850_reg_t)&frame->info; /* arg 1: siginfo */
408	regs->gpr[GPR_ARG2] = (v850_reg_t)&frame->uc; /* arg 2: ucontext */
409
410	set_fs(USER_DS);
411
412#if DEBUG_SIG
413	printk("SIG deliver (%s:%d): sp=%p pc=%08lx pr=%08lx\n",
414		current->comm, current->pid, frame, regs->pc, regs->pr);
415#endif
416
417	return;
418
419give_sigsegv:
420	force_sigsegv(sig, current);
421}
422
423/*
424 * OK, we're invoking a handler
425 */
426
427static void
428handle_signal(unsigned long sig, siginfo_t *info, struct k_sigaction *ka,
429	      sigset_t *oldset,	struct pt_regs * regs)
430{
431	/* Are we from a system call? */
432	if (PT_REGS_SYSCALL (regs)) {
433		/* If so, check system call restarting.. */
434		switch (regs->gpr[GPR_RVAL]) {
435		case -ERESTART_RESTARTBLOCK:
436			current_thread_info()->restart_block.fn =
437				do_no_restart_syscall;
438			/* fall through */
439		case -ERESTARTNOHAND:
440			regs->gpr[GPR_RVAL] = -EINTR;
441			break;
442
443		case -ERESTARTSYS:
444			if (!(ka->sa.sa_flags & SA_RESTART)) {
445				regs->gpr[GPR_RVAL] = -EINTR;
446				break;
447			}
448			/* fallthrough */
449		case -ERESTARTNOINTR:
450			regs->gpr[12] = PT_REGS_SYSCALL (regs);
451			regs->pc -= 4; /* Size of `trap 0' insn.  */
452		}
453
454		PT_REGS_SET_SYSCALL (regs, 0);
455	}
456
457	/* Set up the stack frame */
458	if (ka->sa.sa_flags & SA_SIGINFO)
459		setup_rt_frame(sig, ka, info, oldset, regs);
460	else
461		setup_frame(sig, ka, oldset, regs);
462
463	spin_lock_irq(&current->sighand->siglock);
464	sigorsets(&current->blocked,&current->blocked,&ka->sa.sa_mask);
465	if (!(ka->sa.sa_flags & SA_NODEFER))
466		sigaddset(&current->blocked,sig);
467	recalc_sigpending();
468	spin_unlock_irq(&current->sighand->siglock);
469}
470
471/*
472 * Note that 'init' is a special process: it doesn't get signals it doesn't
473 * want to handle. Thus you cannot kill init even with a SIGKILL even by
474 * mistake.
475 *
476 * Note that we go through the signals twice: once to check the signals that
477 * the kernel can handle, and then we build all the user-level signal handling
478 * stack-frames in one go after that.
479 */
480int do_signal(struct pt_regs *regs, sigset_t *oldset)
481{
482	siginfo_t info;
483	int signr;
484	struct k_sigaction ka;
485
486	/*
487	 * We want the common case to go fast, which
488	 * is why we may in certain cases get here from
489	 * kernel mode. Just return without doing anything
490	 * if so.
491	 */
492	if (!user_mode(regs))
493		return 1;
494
495	if (!oldset)
496		oldset = &current->blocked;
497
498	signr = get_signal_to_deliver(&info, &ka, regs, NULL);
499	if (signr > 0) {
500		/* Whee!  Actually deliver the signal.  */
501		handle_signal(signr, &info, &ka, oldset, regs);
502		return 1;
503	}
504
505	/* Did we come from a system call? */
506	if (PT_REGS_SYSCALL (regs)) {
507		int rval = (int)regs->gpr[GPR_RVAL];
508		/* Restart the system call - no handlers present */
509		if (rval == -ERESTARTNOHAND
510		    || rval == -ERESTARTSYS
511		    || rval == -ERESTARTNOINTR)
512		{
513			regs->gpr[12] = PT_REGS_SYSCALL (regs);
514			regs->pc -= 4; /* Size of `trap 0' insn.  */
515		}
516		else if (rval == -ERESTART_RESTARTBLOCK) {
517			regs->gpr[12] = __NR_restart_syscall;
518			regs->pc -= 4; /* Size of `trap 0' insn.  */
519		}
520	}
521	return 0;
522}
523