1/*
  2 *  linux/arch/m32r/kernel/signal.c
  3 *
  4 *  Copyright (c) 2003  Hitoshi Yamamoto
  5 *
  6 *  Taken from i386 version.
  7 *  Copyright (C) 1991, 1992  Linus Torvalds
  8 *
  9 *  1997-11-28  Modified for POSIX.1b signals by Richard Henderson
 10 *  2000-06-20  Pentium III FXSR, SSE support by Gareth Hughes
 11 */
 12
 13#include <linux/sched.h>
 14#include <linux/mm.h>
 15#include <linux/smp.h>
 16#include <linux/kernel.h>
 17#include <linux/signal.h>
 18#include <linux/errno.h>
 19#include <linux/wait.h>
 20#include <linux/unistd.h>
 21#include <linux/stddef.h>
 22#include <linux/personality.h>
 23#include <linux/tracehook.h>
 24#include <asm/cacheflush.h>
 25#include <asm/ucontext.h>
 26#include <asm/uaccess.h>
 27
 28#define DEBUG_SIG 0
 29
 30/*
 31 * Do a signal return; undo the signal stack.
 32 */
 33
 34struct rt_sigframe
 35{
 36	int sig;
 37	struct siginfo __user *pinfo;
 38	void __user *puc;
 39	struct siginfo info;
 40	struct ucontext uc;
 41//	struct _fpstate fpstate;
 42};
 43
 44static int
 45restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc,
 46		   int *r0_p)
 47{
 48	unsigned int err = 0;
 49
 50	/* Always make any pending restarted system calls return -EINTR */
 51	current_thread_info()->restart_block.fn = do_no_restart_syscall;
 52
 53#define COPY(x)		err |= __get_user(regs->x, &sc->sc_##x)
 54	COPY(r4);
 55	COPY(r5);
 56	COPY(r6);
 57	COPY(pt_regs);
 58	/* COPY(r0); Skip r0 */
 59	COPY(r1);
 60	COPY(r2);
 61	COPY(r3);
 62	COPY(r7);
 63	COPY(r8);
 64	COPY(r9);
 65	COPY(r10);
 66	COPY(r11);
 67	COPY(r12);
 68	COPY(acc0h);
 69	COPY(acc0l);
 70	COPY(acc1h);		/* ISA_DSP_LEVEL2 only */
 71	COPY(acc1l);		/* ISA_DSP_LEVEL2 only */
 72	COPY(psw);
 73	COPY(bpc);
 74	COPY(bbpsw);
 75	COPY(bbpc);
 76	COPY(spu);
 77	COPY(fp);
 78	COPY(lr);
 79	COPY(spi);
 80#undef COPY
 81
 82	regs->syscall_nr = -1;	/* disable syscall checks */
 83	err |= __get_user(*r0_p, &sc->sc_r0);
 84
 85	return err;
 86}
 87
 88asmlinkage int
 89sys_rt_sigreturn(unsigned long r0, unsigned long r1,
 90		 unsigned long r2, unsigned long r3, unsigned long r4,
 91		 unsigned long r5, unsigned long r6, struct pt_regs *regs)
 92{
 93	struct rt_sigframe __user *frame = (struct rt_sigframe __user *)regs->spu;
 94	sigset_t set;
 95	int result;
 96
 97	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
 98		goto badframe;
 99	if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
100		goto badframe;
101
102	set_current_blocked(&set);
103
104	if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &result))
105		goto badframe;
106
107	if (restore_altstack(&frame->uc.uc_stack))
108		goto badframe;
109
110	return result;
111
112badframe:
113	force_sig(SIGSEGV, current);
114	return 0;
115}
116
117/*
118 * Set up a signal frame.
119 */
120
121static int
122setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs,
123	         unsigned long mask)
124{
125	int err = 0;
126
127#define COPY(x)	err |= __put_user(regs->x, &sc->sc_##x)
128	COPY(r4);
129	COPY(r5);
130	COPY(r6);
131	COPY(pt_regs);
132	COPY(r0);
133	COPY(r1);
134	COPY(r2);
135	COPY(r3);
136	COPY(r7);
137	COPY(r8);
138	COPY(r9);
139	COPY(r10);
140	COPY(r11);
141	COPY(r12);
142	COPY(acc0h);
143	COPY(acc0l);
144	COPY(acc1h);		/* ISA_DSP_LEVEL2 only */
145	COPY(acc1l);		/* ISA_DSP_LEVEL2 only */
146	COPY(psw);
147	COPY(bpc);
148	COPY(bbpsw);
149	COPY(bbpc);
150	COPY(spu);
151	COPY(fp);
152	COPY(lr);
153	COPY(spi);
154#undef COPY
155
156	err |= __put_user(mask, &sc->oldmask);
157
158	return err;
159}
160
161/*
162 * Determine which stack to use..
163 */
164static inline void __user *
165get_sigframe(struct k_sigaction *ka, unsigned long sp, size_t frame_size)
166{
167	/* This is the X/Open sanctioned signal stack switching.  */
168	if (ka->sa.sa_flags & SA_ONSTACK) {
169		if (sas_ss_flags(sp) == 0)
170			sp = current->sas_ss_sp + current->sas_ss_size;
171	}
172
173	return (void __user *)((sp - frame_size) & -8ul);
174}
175
176static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
177			   sigset_t *set, struct pt_regs *regs)
178{
179	struct rt_sigframe __user *frame;
180	int err = 0;
181	int signal;
182
183	frame = get_sigframe(ka, regs->spu, sizeof(*frame));
184
185	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
186		goto give_sigsegv;
187
188	signal = current_thread_info()->exec_domain
189		&& current_thread_info()->exec_domain->signal_invmap
190		&& sig < 32
191		? current_thread_info()->exec_domain->signal_invmap[sig]
192		: sig;
193
194	err |= __put_user(signal, &frame->sig);
195	if (err)
196		goto give_sigsegv;
197
198	err |= __put_user(&frame->info, &frame->pinfo);
199	err |= __put_user(&frame->uc, &frame->puc);
200	err |= copy_siginfo_to_user(&frame->info, info);
201	if (err)
202		goto give_sigsegv;
203
204	/* Create the ucontext.  */
205	err |= __put_user(0, &frame->uc.uc_flags);
206	err |= __put_user(0, &frame->uc.uc_link);
207	err |= __save_altstack(&frame->uc.uc_stack, regs->spu);
208	err |= setup_sigcontext(&frame->uc.uc_mcontext, regs, set->sig[0]);
209	err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
210	if (err)
211		goto give_sigsegv;
212
213	/* Set up to return from userspace.  */
214	regs->lr = (unsigned long)ka->sa.sa_restorer;
215
216	/* Set up registers for signal handler */
217	regs->spu = (unsigned long)frame;
218	regs->r0 = signal;	/* Arg for signal handler */
219	regs->r1 = (unsigned long)&frame->info;
220	regs->r2 = (unsigned long)&frame->uc;
221	regs->bpc = (unsigned long)ka->sa.sa_handler;
222
223	set_fs(USER_DS);
224
225#if DEBUG_SIG
226	printk("SIG deliver (%s:%d): sp=%p pc=%p\n",
227		current->comm, current->pid, frame, regs->pc);
228#endif
229
230	return 0;
231
232give_sigsegv:
233	force_sigsegv(sig, current);
234	return -EFAULT;
235}
236
237static int prev_insn(struct pt_regs *regs)
238{
239	u16 inst;
240	if (get_user(inst, (u16 __user *)(regs->bpc - 2)))
241		return -EFAULT;
242	if ((inst & 0xfff0) == 0x10f0)	/* trap ? */
243		regs->bpc -= 2;
244	else
245		regs->bpc -= 4;
246	regs->syscall_nr = -1;
247	return 0;
248}
249
250/*
251 * OK, we're invoking a handler
252 */
253
254static void
255handle_signal(unsigned long sig, struct k_sigaction *ka, siginfo_t *info,
256	      struct pt_regs *regs)
257{
258	/* Are we from a system call? */
259	if (regs->syscall_nr >= 0) {
260		/* If so, check system call restarting.. */
261		switch (regs->r0) {
262		        case -ERESTART_RESTARTBLOCK:
263			case -ERESTARTNOHAND:
264				regs->r0 = -EINTR;
265				break;
266
267			case -ERESTARTSYS:
268				if (!(ka->sa.sa_flags & SA_RESTART)) {
269					regs->r0 = -EINTR;
270					break;
271				}
272			/* fallthrough */
273			case -ERESTARTNOINTR:
274				regs->r0 = regs->orig_r0;
275				if (prev_insn(regs) < 0)
276					return;
277		}
278	}
279
280	/* Set up the stack frame */
281	if (setup_rt_frame(sig, ka, info, sigmask_to_save(), regs))
282		return;
283
284	signal_delivered(sig, info, ka, regs, 0);
285}
286
287/*
288 * Note that 'init' is a special process: it doesn't get signals it doesn't
289 * want to handle. Thus you cannot kill init even with a SIGKILL even by
290 * mistake.
291 */
292static void do_signal(struct pt_regs *regs)
293{
294	siginfo_t info;
295	int signr;
296	struct k_sigaction ka;
297
298	/*
299	 * We want the common case to go fast, which
300	 * is why we may in certain cases get here from
301	 * kernel mode. Just return without doing anything
302	 * if so.
303	 */
304	if (!user_mode(regs))
305		return;
306
307	signr = get_signal_to_deliver(&info, &ka, regs, NULL);
308	if (signr > 0) {
309		/* Re-enable any watchpoints before delivering the
310		 * signal to user space. The processor register will
311		 * have been cleared if the watchpoint triggered
312		 * inside the kernel.
313		 */
314
315		/* Whee!  Actually deliver the signal.  */
316		handle_signal(signr, &ka, &info, regs);
317
318		return;
319	}
320
321	/* Did we come from a system call? */
322	if (regs->syscall_nr >= 0) {
323		/* Restart the system call - no handlers present */
324		if (regs->r0 == -ERESTARTNOHAND ||
325		    regs->r0 == -ERESTARTSYS ||
326		    regs->r0 == -ERESTARTNOINTR) {
327			regs->r0 = regs->orig_r0;
328			prev_insn(regs);
329		} else if (regs->r0 == -ERESTART_RESTARTBLOCK){
330			regs->r0 = regs->orig_r0;
331			regs->r7 = __NR_restart_syscall;
332			prev_insn(regs);
333		}
334	}
335	restore_saved_sigmask();
336}
337
338/*
339 * notification of userspace execution resumption
340 * - triggered by current->work.notify_resume
341 */
342void do_notify_resume(struct pt_regs *regs, __u32 thread_info_flags)
343{
344	/* Pending single-step? */
345	if (thread_info_flags & _TIF_SINGLESTEP)
346		clear_thread_flag(TIF_SINGLESTEP);
347
348	/* deal with pending signal delivery */
349	if (thread_info_flags & _TIF_SIGPENDING)
350		do_signal(regs);
351
352	if (thread_info_flags & _TIF_NOTIFY_RESUME) {
353		clear_thread_flag(TIF_NOTIFY_RESUME);
354		tracehook_notify_resume(regs);
355	}
356}