summaryrefslogtreecommitdiff
path: root/arch/h8300/kernel/signal.c
blob: 1e8070d08770a0cfaa0a4c05c48148ece129de0b (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
/*
 *  linux/arch/h8300/kernel/signal.c
 *
 *  Copyright (C) 1991, 1992  Linus Torvalds
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file COPYING in the main directory of this archive
 * for more details.
 */

/*
 * uClinux H8/300 support by Yoshinori Sato <ysato@users.sourceforge.jp>
 *                and David McCullough <davidm@snapgear.com>
 *
 * Based on
 * Linux/m68k by Hamish Macdonald
 */

/*
 * ++roman (07/09/96): implemented signal stacks (specially for tosemu on
 * Atari :-) Current limitation: Only one sigstack can be active at one time.
 * If a second signal with SA_ONSTACK set arrives while working on a sigstack,
 * SA_ONSTACK is ignored. This behaviour avoids lots of trouble with nested
 * signal handlers!
 */

#include <linux/sched.h>
#include <linux/sched/task_stack.h>
#include <linux/mm.h>
#include <linux/kernel.h>
#include <linux/signal.h>
#include <linux/syscalls.h>
#include <linux/errno.h>
#include <linux/wait.h>
#include <linux/ptrace.h>
#include <linux/unistd.h>
#include <linux/stddef.h>
#include <linux/highuid.h>
#include <linux/personality.h>
#include <linux/tty.h>
#include <linux/binfmts.h>
#include <linux/tracehook.h>

#include <asm/setup.h>
#include <linux/uaccess.h>
#include <asm/pgtable.h>
#include <asm/traps.h>
#include <asm/ucontext.h>

/*
 * Do a signal return; undo the signal stack.
 *
 * Keep the return code on the stack quadword aligned!
 * That makes the cache flush below easier.
 */

struct rt_sigframe {
	long dummy_er0;
	long dummy_vector;
#if defined(CONFIG_CPU_H8S)
	short dummy_exr;
#endif
	long dummy_pc;
	char *pretcode;
	struct siginfo *pinfo;
	void *puc;
	unsigned char retcode[8];
	struct siginfo info;
	struct ucontext uc;
	int sig;
} __packed __aligned(2);

static inline int
restore_sigcontext(struct sigcontext *usc, int *pd0)
{
	struct pt_regs *regs = current_pt_regs();
	int err = 0;
	unsigned int ccr;
	unsigned int usp;
	unsigned int er0;

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

	/* restore passed registers */
#define COPY(r)  do { err |= get_user(regs->r, &usc->sc_##r); } while (0)
	COPY(er1);
	COPY(er2);
	COPY(er3);
	COPY(er5);
	COPY(pc);
	ccr = regs->ccr & 0x10;
	COPY(ccr);
#undef COPY
	regs->ccr &= 0xef;
	regs->ccr |= ccr;
	regs->orig_er0 = -1;		/* disable syscall checks */
	err |= __get_user(usp, &usc->sc_usp);
	regs->sp = usp;

	err |= __get_user(er0, &usc->sc_er0);
	*pd0 = er0;
	return err;
}

asmlinkage int sys_rt_sigreturn(void)
{
	unsigned long usp = rdusp();
	struct rt_sigframe *frame = (struct rt_sigframe *)(usp - 4);
	sigset_t set;
	int er0;

	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(&frame->uc.uc_mcontext, &er0))
		goto badframe;

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

	return er0;

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

static int setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs,
			     unsigned long mask)
{
	int err = 0;

	err |= __put_user(regs->er0, &sc->sc_er0);
	err |= __put_user(regs->er1, &sc->sc_er1);
	err |= __put_user(regs->er2, &sc->sc_er2);
	err |= __put_user(regs->er3, &sc->sc_er3);
	err |= __put_user(regs->er4, &sc->sc_er4);
	err |= __put_user(regs->er5, &sc->sc_er5);
	err |= __put_user(regs->er6, &sc->sc_er6);
	err |= __put_user(rdusp(),   &sc->sc_usp);
	err |= __put_user(regs->pc,  &sc->sc_pc);
	err |= __put_user(regs->ccr, &sc->sc_ccr);
	err |= __put_user(mask,      &sc->sc_mask);

	return err;
}

static inline void __user *
get_sigframe(struct ksignal *ksig, struct pt_regs *regs, size_t frame_size)
{
	return (void __user *)((sigsp(rdusp(), ksig) - frame_size) & -8UL);
}

static int setup_rt_frame(struct ksignal *ksig, sigset_t *set,
			  struct pt_regs *regs)
{
	struct rt_sigframe *frame;
	int err = 0;
	unsigned char *ret;

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

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

	if (ksig->ka.sa.sa_flags & SA_SIGINFO)
		err |= copy_siginfo_to_user(&frame->info, &ksig->info);

	/* Create the ucontext.  */
	err |= __put_user(0, &frame->uc.uc_flags);
	err |= __put_user(0, &frame->uc.uc_link);
	err |= __save_altstack(&frame->uc.uc_stack, rdusp());
	err |= setup_sigcontext(&frame->uc.uc_mcontext, regs, set->sig[0]);
	err |= copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
	if (err)
		return -EFAULT;

	/* Set up to return from userspace.  */
	ret = (unsigned char *)&frame->retcode;
	if (ksig->ka.sa.sa_flags & SA_RESTORER)
		ret = (unsigned char *)(ksig->ka.sa.sa_restorer);
	else {
		/* sub.l er0,er0; mov.b #__NR_rt_sigreturn,r0l; trapa #0 */
		err |= __put_user(0x1a80f800 + (__NR_rt_sigreturn & 0xff),
				  (unsigned long *)(frame->retcode + 0));
		err |= __put_user(0x5700,
				  (unsigned short *)(frame->retcode + 4));
	}
	err |= __put_user(ret, &frame->pretcode);

	if (err)
		return -EFAULT;

	/* Set up registers for signal handler */
	regs->sp  = (unsigned long)frame;
	regs->pc  = (unsigned long)ksig->ka.sa.sa_handler;
	regs->er0 = ksig->sig;
	regs->er1 = (unsigned long)&(frame->info);
	regs->er2 = (unsigned long)&frame->uc;
	regs->er5 = current->mm->start_data;	/* GOT base */

	return 0;
}

static void
handle_restart(struct pt_regs *regs, struct k_sigaction *ka)
{
	switch (regs->er0) {
	case -ERESTARTNOHAND:
		if (!ka)
			goto do_restart;
		regs->er0 = -EINTR;
		break;
	case -ERESTART_RESTARTBLOCK:
		if (!ka) {
			regs->er0 = __NR_restart_syscall;
			regs->pc -= 2;
		} else
			regs->er0 = -EINTR;
		break;
	case -ERESTARTSYS:
		if (!(ka->sa.sa_flags & SA_RESTART)) {
			regs->er0 = -EINTR;
			break;
		}
		/* fallthrough */
	case -ERESTARTNOINTR:
do_restart:
		regs->er0 = regs->orig_er0;
		regs->pc -= 2;
		break;
	}
}

/*
 * OK, we're invoking a handler
 */
static void
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_er0 >= 0)
		handle_restart(regs, &ksig->ka);

	ret = setup_rt_frame(ksig, oldset, regs);

	signal_setup_done(ret, ksig, 0);
}

/*
 * Note that 'init' is a special process: it doesn't get signals it doesn't
 * want to handle. Thus you cannot kill init even with a SIGKILL even by
 * mistake.
 */
static void do_signal(struct pt_regs *regs)
{
	struct ksignal ksig;

	current->thread.esp0 = (unsigned long) regs;

	if (get_signal(&ksig)) {
		/* Whee!  Actually deliver the signal.  */
		handle_signal(&ksig, regs);
		return;
	}
	/* Did we come from a system call? */
	if (regs->orig_er0 >= 0)
		handle_restart(regs, NULL);

	/* If there's no signal to deliver, we just restore the saved mask.  */
	restore_saved_sigmask();
}

asmlinkage void do_notify_resume(struct pt_regs *regs, u32 thread_info_flags)
{
	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(regs);
	}
}