1/*
2 *  linux/arch/h8300/kernel/signal.c
3 *
4 *  Copyright (C) 1991, 1992  Linus Torvalds
5 *
6 * This file is subject to the terms and conditions of the GNU General Public
7 * License.  See the file COPYING in the main directory of this archive
8 * for more details.
9 */
10
11/*
12 * uClinux H8/300 support by Yoshinori Sato <ysato@users.sourceforge.jp>
13 *                and David McCullough <davidm@snapgear.com>
14 *
15 * Based on
16 * Linux/m68k by Hamish Macdonald
17 */
18
19/*
20 * ++roman (07/09/96): implemented signal stacks (specially for tosemu on
21 * Atari :-) Current limitation: Only one sigstack can be active at one time.
22 * If a second signal with SA_ONSTACK set arrives while working on a sigstack,
23 * SA_ONSTACK is ignored. This behaviour avoids lots of trouble with nested
24 * signal handlers!
25 */
26
27#include <linux/sched.h>
28#include <linux/mm.h>
29#include <linux/kernel.h>
30#include <linux/signal.h>
31#include <linux/syscalls.h>
32#include <linux/errno.h>
33#include <linux/wait.h>
34#include <linux/ptrace.h>
35#include <linux/unistd.h>
36#include <linux/stddef.h>
37#include <linux/highuid.h>
38#include <linux/personality.h>
39#include <linux/tty.h>
40#include <linux/binfmts.h>
41#include <linux/freezer.h>
42
43#include <asm/setup.h>
44#include <asm/uaccess.h>
45#include <asm/pgtable.h>
46#include <asm/traps.h>
47#include <asm/ucontext.h>
48
49#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
50
51asmlinkage int do_signal(struct pt_regs *regs, sigset_t *oldset);
52
53/*
54 * Atomically swap in the new signal mask, and wait for a signal.
55 */
56asmlinkage int do_sigsuspend(struct pt_regs *regs)
57{
58	old_sigset_t mask = regs->er3;
59	sigset_t saveset;
60
61	mask &= _BLOCKABLE;
62	spin_lock_irq(&current->sighand->siglock);
63	saveset = current->blocked;
64	siginitset(&current->blocked, mask);
65	recalc_sigpending();
66	spin_unlock_irq(&current->sighand->siglock);
67
68	regs->er0 = -EINTR;
69	while (1) {
70		current->state = TASK_INTERRUPTIBLE;
71		schedule();
72		if (do_signal(regs, &saveset))
73			return -EINTR;
74	}
75}
76
77asmlinkage int
78do_rt_sigsuspend(struct pt_regs *regs)
79{
80	sigset_t *unewset = (sigset_t *)regs->er1;
81	size_t sigsetsize = (size_t)regs->er2;
82	sigset_t saveset, newset;
83
84	if (sigsetsize != sizeof(sigset_t))
85		return -EINVAL;
86
87	if (copy_from_user(&newset, unewset, sizeof(newset)))
88		return -EFAULT;
89	sigdelsetmask(&newset, ~_BLOCKABLE);
90
91	spin_lock_irq(&current->sighand->siglock);
92	saveset = current->blocked;
93	current->blocked = newset;
94	recalc_sigpending();
95	spin_unlock_irq(&current->sighand->siglock);
96
97	regs->er0 = -EINTR;
98	while (1) {
99		current->state = TASK_INTERRUPTIBLE;
100		schedule();
101		if (do_signal(regs, &saveset))
102			return -EINTR;
103	}
104}
105
106asmlinkage int
107sys_sigaction(int sig, const struct old_sigaction *act,
108	      struct old_sigaction *oact)
109{
110	struct k_sigaction new_ka, old_ka;
111	int ret;
112
113	if (act) {
114		old_sigset_t mask;
115		if (!access_ok(VERIFY_READ, act, sizeof(*act)) ||
116		    __get_user(new_ka.sa.sa_handler, &act->sa_handler) ||
117		    __get_user(new_ka.sa.sa_restorer, &act->sa_restorer))
118			return -EFAULT;
119		__get_user(new_ka.sa.sa_flags, &act->sa_flags);
120		__get_user(mask, &act->sa_mask);
121		siginitset(&new_ka.sa.sa_mask, mask);
122	}
123
124	ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
125
126	if (!ret && oact) {
127		if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) ||
128		    __put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||
129		    __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer))
130			return -EFAULT;
131		__put_user(old_ka.sa.sa_flags, &oact->sa_flags);
132		__put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask);
133	}
134
135	return ret;
136}
137
138asmlinkage int
139sys_sigaltstack(const stack_t *uss, stack_t *uoss)
140{
141	return do_sigaltstack(uss, uoss, rdusp());
142}
143
144
145/*
146 * Do a signal return; undo the signal stack.
147 *
148 * Keep the return code on the stack quadword aligned!
149 * That makes the cache flush below easier.
150 */
151
152struct sigframe
153{
154	long dummy_er0;
155	long dummy_vector;
156#if defined(CONFIG_CPU_H8S)
157	short dummy_exr;
158#endif
159	long dummy_pc;
160	char *pretcode;
161	unsigned char retcode[8];
162	unsigned long extramask[_NSIG_WORDS-1];
163	struct sigcontext sc;
164	int sig;
165} __attribute__((aligned(2),packed));
166
167struct rt_sigframe
168{
169	long dummy_er0;
170	long dummy_vector;
171#if defined(CONFIG_CPU_H8S)
172	short dummy_exr;
173#endif
174	long dummy_pc;
175	char *pretcode;
176	struct siginfo *pinfo;
177	void *puc;
178	unsigned char retcode[8];
179	struct siginfo info;
180	struct ucontext uc;
181	int sig;
182} __attribute__((aligned(2),packed));
183
184static inline int
185restore_sigcontext(struct pt_regs *regs, struct sigcontext *usc,
186		   int *pd0)
187{
188	int err = 0;
189	unsigned int ccr;
190	unsigned int usp;
191	unsigned int er0;
192
193	/* Always make any pending restarted system calls return -EINTR */
194	current_thread_info()->restart_block.fn = do_no_restart_syscall;
195
196#define COPY(r) err |= __get_user(regs->r, &usc->sc_##r)    /* restore passed registers */
197	COPY(er1);
198	COPY(er2);
199	COPY(er3);
200	COPY(er5);
201	COPY(pc);
202	ccr = regs->ccr & 0x10;
203	COPY(ccr);
204#undef COPY
205	regs->ccr &= 0xef;
206	regs->ccr |= ccr;
207	regs->orig_er0 = -1;		/* disable syscall checks */
208	err |= __get_user(usp, &usc->sc_usp);
209	wrusp(usp);
210
211	err |= __get_user(er0, &usc->sc_er0);
212	*pd0 = er0;
213	return err;
214}
215
216asmlinkage int do_sigreturn(unsigned long __unused,...)
217{
218	struct pt_regs *regs = (struct pt_regs *) (&__unused - 1);
219	unsigned long usp = rdusp();
220	struct sigframe *frame = (struct sigframe *)(usp - 4);
221	sigset_t set;
222	int er0;
223
224	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
225		goto badframe;
226	if (__get_user(set.sig[0], &frame->sc.sc_mask) ||
227	    (_NSIG_WORDS > 1 &&
228	     __copy_from_user(&set.sig[1], &frame->extramask,
229			      sizeof(frame->extramask))))
230		goto badframe;
231
232	sigdelsetmask(&set, ~_BLOCKABLE);
233	spin_lock_irq(&current->sighand->siglock);
234	current->blocked = set;
235	recalc_sigpending();
236	spin_unlock_irq(&current->sighand->siglock);
237
238	if (restore_sigcontext(regs, &frame->sc, &er0))
239		goto badframe;
240	return er0;
241
242badframe:
243	force_sig(SIGSEGV, current);
244	return 0;
245}
246
247asmlinkage int do_rt_sigreturn(unsigned long __unused,...)
248{
249	struct pt_regs *regs = (struct pt_regs *) &__unused;
250	unsigned long usp = rdusp();
251	struct rt_sigframe *frame = (struct rt_sigframe *)(usp - 4);
252	sigset_t set;
253	int er0;
254
255	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
256		goto badframe;
257	if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
258		goto badframe;
259
260	sigdelsetmask(&set, ~_BLOCKABLE);
261	spin_unlock_irq(&current->sighand->siglock);
262	current->blocked = set;
263	recalc_sigpending();
264	spin_lock_irq(&current->sighand->siglock);
265
266	if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &er0))
267		goto badframe;
268
269	if (do_sigaltstack(&frame->uc.uc_stack, NULL, usp) == -EFAULT)
270		goto badframe;
271
272	return er0;
273
274badframe:
275	force_sig(SIGSEGV, current);
276	return 0;
277}
278
279static int setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs,
280			     unsigned long mask)
281{
282	int err = 0;
283
284	err |= __put_user(regs->er0, &sc->sc_er0);
285	err |= __put_user(regs->er1, &sc->sc_er1);
286	err |= __put_user(regs->er2, &sc->sc_er2);
287	err |= __put_user(regs->er3, &sc->sc_er3);
288	err |= __put_user(regs->er4, &sc->sc_er4);
289	err |= __put_user(regs->er5, &sc->sc_er5);
290	err |= __put_user(regs->er6, &sc->sc_er6);
291	err |= __put_user(rdusp(),   &sc->sc_usp);
292	err |= __put_user(regs->pc,  &sc->sc_pc);
293	err |= __put_user(regs->ccr, &sc->sc_ccr);
294	err |= __put_user(mask,      &sc->sc_mask);
295
296	return err;
297}
298
299static inline void *
300get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size)
301{
302	unsigned long usp;
303
304	/* Default to using normal stack.  */
305	usp = rdusp();
306
307	/* This is the X/Open sanctioned signal stack switching.  */
308	if (ka->sa.sa_flags & SA_ONSTACK) {
309		if (!sas_ss_flags(usp))
310			usp = current->sas_ss_sp + current->sas_ss_size;
311	}
312	return (void *)((usp - frame_size) & -8UL);
313}
314
315static void setup_frame (int sig, struct k_sigaction *ka,
316			 sigset_t *set, struct pt_regs *regs)
317{
318	struct sigframe *frame;
319	int err = 0;
320	int usig;
321	unsigned char *ret;
322
323	frame = get_sigframe(ka, regs, sizeof(*frame));
324
325	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
326		goto give_sigsegv;
327
328	usig = current_thread_info()->exec_domain
329		&& current_thread_info()->exec_domain->signal_invmap
330		&& sig < 32
331		? current_thread_info()->exec_domain->signal_invmap[sig]
332		: sig;
333
334	err |= __put_user(usig, &frame->sig);
335	if (err)
336		goto give_sigsegv;
337
338	err |= setup_sigcontext(&frame->sc, regs, set->sig[0]);
339	if (err)
340		goto give_sigsegv;
341
342	if (_NSIG_WORDS > 1) {
343		err |= copy_to_user(frame->extramask, &set->sig[1],
344				    sizeof(frame->extramask));
345		if (err)
346			goto give_sigsegv;
347	}
348
349	ret = frame->retcode;
350	if (ka->sa.sa_flags & SA_RESTORER)
351		ret = (unsigned char *)(ka->sa.sa_restorer);
352	else {
353		/* sub.l er0,er0; mov.b #__NR_sigreturn,r0l; trapa #0 */
354		err != __put_user(0x1a80f800 + (__NR_sigreturn & 0xff),
355				  (unsigned long *)(frame->retcode + 0));
356		err |= __put_user(0x5700, (unsigned short *)(frame->retcode + 4));
357	}
358
359	/* Set up to return from userspace.  */
360	err |= __put_user(ret, &frame->pretcode);
361
362	if (err)
363		goto give_sigsegv;
364
365	/* Set up registers for signal handler */
366	wrusp ((unsigned long) frame);
367	regs->pc = (unsigned long) ka->sa.sa_handler;
368	regs->er0 = (current_thread_info()->exec_domain
369			   && current_thread_info()->exec_domain->signal_invmap
370			   && sig < 32
371			   ? current_thread_info()->exec_domain->signal_invmap[sig]
372		          : sig);
373	regs->er1 = (unsigned long)&(frame->sc);
374	regs->er5 = current->mm->start_data;	/* GOT base */
375
376	return;
377
378give_sigsegv:
379	force_sigsegv(sig, current);
380}
381
382static void setup_rt_frame (int sig, struct k_sigaction *ka, siginfo_t *info,
383			    sigset_t *set, struct pt_regs *regs)
384{
385	struct rt_sigframe *frame;
386	int err = 0;
387	int usig;
388	unsigned char *ret;
389
390	frame = get_sigframe(ka, regs, sizeof(*frame));
391
392	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
393		goto give_sigsegv;
394
395	usig = current_thread_info()->exec_domain
396		&& current_thread_info()->exec_domain->signal_invmap
397		&& sig < 32
398		? current_thread_info()->exec_domain->signal_invmap[sig]
399		: sig;
400
401	err |= __put_user(usig, &frame->sig);
402	if (err)
403		goto give_sigsegv;
404
405	err |= __put_user(&frame->info, &frame->pinfo);
406	err |= __put_user(&frame->uc, &frame->puc);
407	err |= copy_siginfo_to_user(&frame->info, info);
408	if (err)
409		goto give_sigsegv;
410
411	/* Create the ucontext.  */
412	err |= __put_user(0, &frame->uc.uc_flags);
413	err |= __put_user(0, &frame->uc.uc_link);
414	err |= __put_user((void *)current->sas_ss_sp,
415			  &frame->uc.uc_stack.ss_sp);
416	err |= __put_user(sas_ss_flags(rdusp()),
417			  &frame->uc.uc_stack.ss_flags);
418	err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
419	err |= setup_sigcontext(&frame->uc.uc_mcontext, regs, set->sig[0]);
420	err |= copy_to_user (&frame->uc.uc_sigmask, set, sizeof(*set));
421	if (err)
422		goto give_sigsegv;
423
424	/* Set up to return from userspace.  */
425	ret = frame->retcode;
426	if (ka->sa.sa_flags & SA_RESTORER)
427		ret = (unsigned char *)(ka->sa.sa_restorer);
428	else {
429		/* sub.l er0,er0; mov.b #__NR_sigreturn,r0l; trapa #0 */
430		err != __put_user(0x1a80f800 + (__NR_sigreturn & 0xff),
431				  (unsigned long *)(frame->retcode + 0));
432		err |= __put_user(0x5700, (unsigned short *)(frame->retcode + 4));
433	}
434	err |= __put_user(ret, &frame->pretcode);
435
436	if (err)
437		goto give_sigsegv;
438
439	/* Set up registers for signal handler */
440	wrusp ((unsigned long) frame);
441	regs->pc  = (unsigned long) ka->sa.sa_handler;
442	regs->er0 = (current_thread_info()->exec_domain
443		     && current_thread_info()->exec_domain->signal_invmap
444		     && sig < 32
445		     ? current_thread_info()->exec_domain->signal_invmap[sig]
446		     : sig);
447	regs->er1 = (unsigned long)&(frame->info);
448	regs->er2 = (unsigned long)&frame->uc;
449	regs->er5 = current->mm->start_data;	/* GOT base */
450
451	return;
452
453give_sigsegv:
454	force_sigsegv(sig, current);
455}
456
457/*
458 * OK, we're invoking a handler
459 */
460static void
461handle_signal(unsigned long sig, siginfo_t *info, struct k_sigaction *ka,
462	      sigset_t *oldset,	struct pt_regs * regs)
463{
464	/* are we from a system call? */
465	if (regs->orig_er0 >= 0) {
466		switch (regs->er0) {
467		        case -ERESTART_RESTARTBLOCK:
468			case -ERESTARTNOHAND:
469				regs->er0 = -EINTR;
470				break;
471
472			case -ERESTARTSYS:
473				if (!(ka->sa.sa_flags & SA_RESTART)) {
474					regs->er0 = -EINTR;
475					break;
476				}
477			/* fallthrough */
478			case -ERESTARTNOINTR:
479				regs->er0 = regs->orig_er0;
480				regs->pc -= 2;
481		}
482	}
483
484	/* set up the stack frame */
485	if (ka->sa.sa_flags & SA_SIGINFO)
486		setup_rt_frame(sig, ka, info, oldset, regs);
487	else
488		setup_frame(sig, ka, oldset, regs);
489
490	spin_lock_irq(&current->sighand->siglock);
491	sigorsets(&current->blocked,&current->blocked,&ka->sa.sa_mask);
492	if (!(ka->sa.sa_flags & SA_NODEFER))
493		sigaddset(&current->blocked,sig);
494	recalc_sigpending();
495	spin_unlock_irq(&current->sighand->siglock);
496}
497
498/*
499 * Note that 'init' is a special process: it doesn't get signals it doesn't
500 * want to handle. Thus you cannot kill init even with a SIGKILL even by
501 * mistake.
502 */
503asmlinkage int do_signal(struct pt_regs *regs, sigset_t *oldset)
504{
505	siginfo_t info;
506	int signr;
507	struct k_sigaction ka;
508
509	/*
510	 * We want the common case to go fast, which
511	 * is why we may in certain cases get here from
512	 * kernel mode. Just return without doing anything
513	 * if so.
514	 */
515	if ((regs->ccr & 0x10))
516		return 1;
517
518	if (try_to_freeze())
519		goto no_signal;
520
521	current->thread.esp0 = (unsigned long) regs;
522
523	if (!oldset)
524		oldset = &current->blocked;
525
526	signr = get_signal_to_deliver(&info, &ka, regs, NULL);
527	if (signr > 0) {
528		/* Whee!  Actually deliver the signal.  */
529		handle_signal(signr, &info, &ka, oldset, regs);
530		return 1;
531	}
532 no_signal:
533	/* Did we come from a system call? */
534	if (regs->orig_er0 >= 0) {
535		/* Restart the system call - no handlers present */
536		if (regs->er0 == -ERESTARTNOHAND ||
537		    regs->er0 == -ERESTARTSYS ||
538		    regs->er0 == -ERESTARTNOINTR) {
539			regs->er0 = regs->orig_er0;
540			regs->pc -= 2;
541		}
542		if (regs->er0 == -ERESTART_RESTARTBLOCK){
543			regs->er0 = __NR_restart_syscall;
544			regs->pc -= 2;
545		}
546	}
547	return 0;
548}
549