summaryrefslogtreecommitdiffstats
path: root/arch/mn10300/kernel/signal.c
blob: 2f3cb573423564b52c9227663de5b479d924df9c (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
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
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
/* MN10300 Signal handling
 *
 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells (dhowells@redhat.com)
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public Licence
 * as published by the Free Software Foundation; either version
 * 2 of the Licence, or (at your option) any later version.
 */

#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/suspend.h>
#include <linux/tracehook.h>
#include <asm/cacheflush.h>
#include <asm/ucontext.h>
#include <linux/uaccess.h>
#include <asm/fpu.h>
#include "sigframe.h"

#define DEBUG_SIG 0

/*
 * do a signal return; undo the signal stack.
 */
static int restore_sigcontext(struct pt_regs *regs,
			      struct sigcontext __user *sc, long *_d0)
{
	unsigned int err = 0;

	/* Always make any pending restarted system calls return -EINTR */
	current->restart_block.fn = do_no_restart_syscall;

	if (is_using_fpu(current))
		fpu_kill_state(current);

#define COPY(x) err |= __get_user(regs->x, &sc->x)
	COPY(d1); COPY(d2); COPY(d3);
	COPY(a0); COPY(a1); COPY(a2); COPY(a3);
	COPY(e0); COPY(e1); COPY(e2); COPY(e3);
	COPY(e4); COPY(e5); COPY(e6); COPY(e7);
	COPY(lar); COPY(lir);
	COPY(mdr); COPY(mdrq);
	COPY(mcvf); COPY(mcrl); COPY(mcrh);
	COPY(sp); COPY(pc);
#undef COPY

	{
		unsigned int tmpflags;
#ifndef CONFIG_MN10300_USING_JTAG
#define USER_EPSW (EPSW_FLAG_Z | EPSW_FLAG_N | EPSW_FLAG_C | EPSW_FLAG_V | \
		   EPSW_T | EPSW_nAR)
#else
#define USER_EPSW (EPSW_FLAG_Z | EPSW_FLAG_N | EPSW_FLAG_C | EPSW_FLAG_V | \
		   EPSW_nAR)
#endif
		err |= __get_user(tmpflags, &sc->epsw);
		regs->epsw = (regs->epsw & ~USER_EPSW) |
		  (tmpflags & USER_EPSW);
		regs->orig_d0 = -1;		/* disable syscall checks */
	}

	{
		struct fpucontext *buf;
		err |= __get_user(buf, &sc->fpucontext);
		if (buf) {
			if (!access_ok(VERIFY_READ, buf, sizeof(*buf)))
				goto badframe;
			err |= fpu_restore_sigcontext(buf);
		}
	}

	err |= __get_user(*_d0, &sc->d0);
	return err;

badframe:
	return 1;
}

/*
 * standard signal return syscall
 */
asmlinkage long sys_sigreturn(void)
{
	struct sigframe __user *frame;
	sigset_t set;
	long d0;

	frame = (struct sigframe __user *) current_frame()->sp;
	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
		goto badframe;
	if (__get_user(set.sig[0], &frame->sc.oldmask))
		goto badframe;

	if (_NSIG_WORDS > 1 &&
	    __copy_from_user(&set.sig[1], &frame->extramask,
			     sizeof(frame->extramask)))
		goto badframe;

	set_current_blocked(&set);

	if (restore_sigcontext(current_frame(), &frame->sc, &d0))
		goto badframe;

	return d0;

badframe:
	force_sig(SIGSEGV, current);
	return 0;
}

/*
 * realtime signal return syscall
 */
asmlinkage long sys_rt_sigreturn(void)
{
	struct rt_sigframe __user *frame;
	sigset_t set;
	long d0;

	frame = (struct rt_sigframe __user *) current_frame()->sp;
	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
		goto badframe;
	if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
		goto badframe;

	set_current_blocked(&set);

	if (restore_sigcontext(current_frame(), &frame->uc.uc_mcontext, &d0))
		goto badframe;

	if (restore_altstack(&frame->uc.uc_stack))
		goto badframe;

	return d0;

badframe:
	force_sig(SIGSEGV, current);
	return 0;
}

/*
 * store the userspace context into a signal frame
 */
static int setup_sigcontext(struct sigcontext __user *sc,
			    struct fpucontext *fpuctx,
			    struct pt_regs *regs,
			    unsigned long mask)
{
	int tmp, err = 0;

#define COPY(x) err |= __put_user(regs->x, &sc->x)
	COPY(d0); COPY(d1); COPY(d2); COPY(d3);
	COPY(a0); COPY(a1); COPY(a2); COPY(a3);
	COPY(e0); COPY(e1); COPY(e2); COPY(e3);
	COPY(e4); COPY(e5); COPY(e6); COPY(e7);
	COPY(lar); COPY(lir);
	COPY(mdr); COPY(mdrq);
	COPY(mcvf); COPY(mcrl); COPY(mcrh);
	COPY(sp); COPY(epsw); COPY(pc);
#undef COPY

	tmp = fpu_setup_sigcontext(fpuctx);
	if (tmp < 0)
		err = 1;
	else
		err |= __put_user(tmp ? fpuctx : NULL, &sc->fpucontext);

	/* non-iBCS2 extensions.. */
	err |= __put_user(mask, &sc->oldmask);

	return err;
}

/*
 * determine which stack to use..
 */
static inline void __user *get_sigframe(struct ksignal *ksig,
					struct pt_regs *regs,
					size_t frame_size)
{
	unsigned long sp = sigsp(regs->sp, ksig);

	return (void __user *) ((sp - frame_size) & ~7UL);
}

/*
 * set up a normal signal frame
 */
static int setup_frame(struct ksignal *ksig, sigset_t *set,
		       struct pt_regs *regs)
{
	struct sigframe __user *frame;
	int sig = ksig->sig;

	frame = get_sigframe(ksig, regs, sizeof(*frame));

	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
		return -EFAULT;

	if (__put_user(sig, &frame->sig) < 0 ||
	    __put_user(&frame->sc, &frame->psc) < 0)
		return -EFAULT;

	if (setup_sigcontext(&frame->sc, &frame->fpuctx, regs, set->sig[0]))
		return -EFAULT;

	if (_NSIG_WORDS > 1) {
		if (__copy_to_user(frame->extramask, &set->sig[1],
				   sizeof(frame->extramask)))
			return -EFAULT;
	}

	/* set up to return from userspace.  If provided, use a stub already in
	 * userspace */
	if (ksig->ka.sa.sa_flags & SA_RESTORER) {
		if (__put_user(ksig->ka.sa.sa_restorer, &frame->pretcode))
			return -EFAULT;
	} else {
		if (__put_user((void (*)(void))frame->retcode,
			       &frame->pretcode))
			return -EFAULT;
		/* this is mov $,d0; syscall 0 */
		if (__put_user(0x2c, (char *)(frame->retcode + 0)) ||
		    __put_user(__NR_sigreturn, (char *)(frame->retcode + 1)) ||
		    __put_user(0x00, (char *)(frame->retcode + 2)) ||
		    __put_user(0xf0, (char *)(frame->retcode + 3)) ||
		    __put_user(0xe0, (char *)(frame->retcode + 4)))
			return -EFAULT;
		flush_icache_range((unsigned long) frame->retcode,
				   (unsigned long) frame->retcode + 5);
	}

	/* set up registers for signal handler */
	regs->sp = (unsigned long) frame;
	regs->pc = (unsigned long) ksig->ka.sa.sa_handler;
	regs->d0 = sig;
	regs->d1 = (unsigned long) &frame->sc;

#if DEBUG_SIG
	printk(KERN_DEBUG "SIG deliver %d (%s:%d): sp=%p pc=%lx ra=%p\n",
	       sig, current->comm, current->pid, frame, regs->pc,
	       frame->pretcode);
#endif

	return 0;
}

/*
 * set up a realtime signal frame
 */
static int setup_rt_frame(struct ksignal *ksig, sigset_t *set,
			  struct pt_regs *regs)
{
	struct rt_sigframe __user *frame;
	int sig = ksig->sig;

	frame = get_sigframe(ksig, regs, sizeof(*frame));

	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
		return -EFAULT;

	if (__put_user(sig, &frame->sig) ||
	    __put_user(&frame->info, &frame->pinfo) ||
	    __put_user(&frame->uc, &frame->puc) ||
	    copy_siginfo_to_user(&frame->info, &ksig->info))
		return -EFAULT;

	/* create the ucontext.  */
	if (__put_user(0, &frame->uc.uc_flags) ||
	    __put_user(0, &frame->uc.uc_link) ||
	    __save_altstack(&frame->uc.uc_stack, regs->sp) ||
	    setup_sigcontext(&frame->uc.uc_mcontext,
			     &frame->fpuctx, regs, set->sig[0]) ||
	    __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)))
		return -EFAULT;

	/* set up to return from userspace.  If provided, use a stub already in
	 * userspace */
	if (ksig->ka.sa.sa_flags & SA_RESTORER) {
		if (__put_user(ksig->ka.sa.sa_restorer, &frame->pretcode))
			return -EFAULT;

	} else {
		if (__put_user((void(*)(void))frame->retcode,
			       &frame->pretcode) ||
		    /* This is mov $,d0; syscall 0 */
		    __put_user(0x2c, (char *)(frame->retcode + 0)) ||
		    __put_user(__NR_rt_sigreturn,
			       (char *)(frame->retcode + 1)) ||
		    __put_user(0x00, (char *)(frame->retcode + 2)) ||
		    __put_user(0xf0, (char *)(frame->retcode + 3)) ||
		    __put_user(0xe0, (char *)(frame->retcode + 4)))
			return -EFAULT;

		flush_icache_range((u_long) frame->retcode,
				   (u_long) frame->retcode + 5);
	}

	/* Set up registers for signal handler */
	regs->sp = (unsigned long) frame;
	regs->pc = (unsigned long) ksig->ka.sa.sa_handler;
	regs->d0 = sig;
	regs->d1 = (long) &frame->info;

#if DEBUG_SIG
	printk(KERN_DEBUG "SIG deliver %d (%s:%d): sp=%p pc=%lx ra=%p\n",
	       sig, current->comm, current->pid, frame, regs->pc,
	       frame->pretcode);
#endif

	return 0;
}

static inline void stepback(struct pt_regs *regs)
{
	regs->pc -= 2;
	regs->orig_d0 = -1;
}

/*
 * handle the actual delivery of a signal to userspace
 */
static int handle_signal(struct ksignal *ksig, struct pt_regs *regs)
{
	sigset_t *oldset = sigmask_to_save();
	int ret;

	/* Are we from a system call? */
	if (regs->orig_d0 >= 0) {
		/* If so, check system call restarting.. */
		switch (regs->d0) {
		case -ERESTART_RESTARTBLOCK:
		case -ERESTARTNOHAND:
			regs->d0 = -EINTR;
			break;

		case -ERESTARTSYS:
			if (!(ksig->ka.sa.sa_flags & SA_RESTART)) {
				regs->d0 = -EINTR;
				break;
			}

			/* fallthrough */
		case -ERESTARTNOINTR:
			regs->d0 = regs->orig_d0;
			stepback(regs);
		}
	}

	/* Set up the stack frame */
	if (ksig->ka.sa.sa_flags & SA_SIGINFO)
		ret = setup_rt_frame(ksig, oldset, regs);
	else
		ret = setup_frame(ksig, oldset, regs);

	signal_setup_done(ret, ksig, test_thread_flag(TIF_SINGLESTEP));
	return 0;
}

/*
 * handle a potential signal
 */
static void do_signal(struct pt_regs *regs)
{
	struct ksignal ksig;

	if (get_signal(&ksig)) {
		handle_signal(&ksig, regs);
		return;
	}

	/* did we come from a system call? */
	if (regs->orig_d0 >= 0) {
		/* restart the system call - no handlers present */
		switch (regs->d0) {
		case -ERESTARTNOHAND:
		case -ERESTARTSYS:
		case -ERESTARTNOINTR:
			regs->d0 = regs->orig_d0;
			stepback(regs);
			break;

		case -ERESTART_RESTARTBLOCK:
			regs->d0 = __NR_restart_syscall;
			stepback(regs);
			break;
		}
	}

	/* if there's no signal to deliver, we just put the saved sigmask
	 * back */
	restore_saved_sigmask();
}

/*
 * notification of userspace execution resumption
 * - triggered by current->work.notify_resume
 */
asmlinkage void do_notify_resume(struct pt_regs *regs, u32 thread_info_flags)
{
	/* Pending single-step? */
	if (thread_info_flags & _TIF_SINGLESTEP) {
#ifndef CONFIG_MN10300_USING_JTAG
		regs->epsw |= EPSW_T;
		clear_thread_flag(TIF_SINGLESTEP);
#else
		BUG(); /* no h/w single-step if using JTAG unit */
#endif
	}

	/* deal with pending signal delivery */
	if (thread_info_flags & _TIF_SIGPENDING)
		do_signal(regs);

	if (thread_info_flags & _TIF_NOTIFY_RESUME) {
		clear_thread_flag(TIF_NOTIFY_RESUME);
		tracehook_notify_resume(current_frame());
	}
}
OpenPOWER on IntegriCloud