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->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 ksignal *ksig, unsigned long sp, size_t frame_size)
166{
167	return (void __user *)((sigsp(sp, ksig) - frame_size) & -8ul);
168}
169
170static int setup_rt_frame(struct ksignal *ksig, sigset_t *set,
171			  struct pt_regs *regs)
172{
173	struct rt_sigframe __user *frame;
174	int err = 0;
175	int sig = ksig->sig;
176
177	frame = get_sigframe(ksig, regs->spu, sizeof(*frame));
178
179	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
180		return -EFAULT;
181
182	err |= __put_user(sig, &frame->sig);
183	if (err)
184		return -EFAULT;
185
186	err |= __put_user(&frame->info, &frame->pinfo);
187	err |= __put_user(&frame->uc, &frame->puc);
188	err |= copy_siginfo_to_user(&frame->info, &ksig->info);
189	if (err)
190		return -EFAULT;
191
192	/* Create the ucontext.  */
193	err |= __put_user(0, &frame->uc.uc_flags);
194	err |= __put_user(0, &frame->uc.uc_link);
195	err |= __save_altstack(&frame->uc.uc_stack, regs->spu);
196	err |= setup_sigcontext(&frame->uc.uc_mcontext, regs, set->sig[0]);
197	err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
198	if (err)
199		return -EFAULT;
200
201	/* Set up to return from userspace.  */
202	regs->lr = (unsigned long)ksig->ka.sa.sa_restorer;
203
204	/* Set up registers for signal handler */
205	regs->spu = (unsigned long)frame;
206	regs->r0 = sig;	/* Arg for signal handler */
207	regs->r1 = (unsigned long)&frame->info;
208	regs->r2 = (unsigned long)&frame->uc;
209	regs->bpc = (unsigned long)ksig->ka.sa.sa_handler;
210
211#if DEBUG_SIG
212	printk("SIG deliver (%s:%d): sp=%p pc=%p\n",
213		current->comm, current->pid, frame, regs->pc);
214#endif
215
216	return 0;
217}
218
219static int prev_insn(struct pt_regs *regs)
220{
221	u16 inst;
222	if (get_user(inst, (u16 __user *)(regs->bpc - 2)))
223		return -EFAULT;
224	if ((inst & 0xfff0) == 0x10f0)	/* trap ? */
225		regs->bpc -= 2;
226	else
227		regs->bpc -= 4;
228	regs->syscall_nr = -1;
229	return 0;
230}
231
232/*
233 * OK, we're invoking a handler
234 */
235
236static void
237handle_signal(struct ksignal *ksig, struct pt_regs *regs)
238{
239	int ret;
240
241	/* Are we from a system call? */
242	if (regs->syscall_nr >= 0) {
243		/* If so, check system call restarting.. */
244		switch (regs->r0) {
245		        case -ERESTART_RESTARTBLOCK:
246			case -ERESTARTNOHAND:
247				regs->r0 = -EINTR;
248				break;
249
250			case -ERESTARTSYS:
251				if (!(ksig->ka.sa.sa_flags & SA_RESTART)) {
252					regs->r0 = -EINTR;
253					break;
254				}
255			/* fallthrough */
256			case -ERESTARTNOINTR:
257				regs->r0 = regs->orig_r0;
258				if (prev_insn(regs) < 0)
259					return;
260		}
261	}
262
263	/* Set up the stack frame */
264	ret = setup_rt_frame(ksig, sigmask_to_save(), regs);
265
266	signal_setup_done(ret, ksig, 0);
267}
268
269/*
270 * Note that 'init' is a special process: it doesn't get signals it doesn't
271 * want to handle. Thus you cannot kill init even with a SIGKILL even by
272 * mistake.
273 */
274static void do_signal(struct pt_regs *regs)
275{
276	struct ksignal ksig;
277
278	/*
279	 * We want the common case to go fast, which
280	 * is why we may in certain cases get here from
281	 * kernel mode. Just return without doing anything
282	 * if so.
283	 */
284	if (!user_mode(regs))
285		return;
286
287	if (get_signal(&ksig)) {
288		/* Re-enable any watchpoints before delivering the
289		 * signal to user space. The processor register will
290		 * have been cleared if the watchpoint triggered
291		 * inside the kernel.
292		 */
293
294		/* Whee!  Actually deliver the signal.  */
295		handle_signal(&ksig, regs);
296
297		return;
298	}
299
300	/* Did we come from a system call? */
301	if (regs->syscall_nr >= 0) {
302		/* Restart the system call - no handlers present */
303		if (regs->r0 == -ERESTARTNOHAND ||
304		    regs->r0 == -ERESTARTSYS ||
305		    regs->r0 == -ERESTARTNOINTR) {
306			regs->r0 = regs->orig_r0;
307			prev_insn(regs);
308		} else if (regs->r0 == -ERESTART_RESTARTBLOCK){
309			regs->r0 = regs->orig_r0;
310			regs->r7 = __NR_restart_syscall;
311			prev_insn(regs);
312		}
313	}
314	restore_saved_sigmask();
315}
316
317/*
318 * notification of userspace execution resumption
319 * - triggered by current->work.notify_resume
320 */
321void do_notify_resume(struct pt_regs *regs, __u32 thread_info_flags)
322{
323	/* Pending single-step? */
324	if (thread_info_flags & _TIF_SINGLESTEP)
325		clear_thread_flag(TIF_SINGLESTEP);
326
327	/* deal with pending signal delivery */
328	if (thread_info_flags & _TIF_SIGPENDING)
329		do_signal(regs);
330
331	if (thread_info_flags & _TIF_NOTIFY_RESUME) {
332		clear_thread_flag(TIF_NOTIFY_RESUME);
333		tracehook_notify_resume(regs);
334	}
335}
336