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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/tracehook.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/*
50 * Do a signal return; undo the signal stack.
51 *
52 * Keep the return code on the stack quadword aligned!
53 * That makes the cache flush below easier.
54 */
55
56struct rt_sigframe {
57 long dummy_er0;
58 long dummy_vector;
59#if defined(CONFIG_CPU_H8S)
60 short dummy_exr;
61#endif
62 long dummy_pc;
63 char *pretcode;
64 struct siginfo *pinfo;
65 void *puc;
66 unsigned char retcode[8];
67 struct siginfo info;
68 struct ucontext uc;
69 int sig;
70} __packed __aligned(2);
71
72static inline int
73restore_sigcontext(struct sigcontext *usc, int *pd0)
74{
75 struct pt_regs *regs = current_pt_regs();
76 int err = 0;
77 unsigned int ccr;
78 unsigned int usp;
79 unsigned int er0;
80
81 /* Always make any pending restarted system calls return -EINTR */
82 current_thread_info()->restart_block.fn = do_no_restart_syscall;
83
84 /* restore passed registers */
85#define COPY(r) do { err |= get_user(regs->r, &usc->sc_##r); } while (0)
86 COPY(er1);
87 COPY(er2);
88 COPY(er3);
89 COPY(er5);
90 COPY(pc);
91 ccr = regs->ccr & 0x10;
92 COPY(ccr);
93#undef COPY
94 regs->ccr &= 0xef;
95 regs->ccr |= ccr;
96 regs->orig_er0 = -1; /* disable syscall checks */
97 err |= __get_user(usp, &usc->sc_usp);
98 regs->sp = usp;
99
100 err |= __get_user(er0, &usc->sc_er0);
101 *pd0 = er0;
102 return err;
103}
104
105asmlinkage int sys_rt_sigreturn(void)
106{
107 unsigned long usp = rdusp();
108 struct rt_sigframe *frame = (struct rt_sigframe *)(usp - 4);
109 sigset_t set;
110 int er0;
111
112 if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
113 goto badframe;
114 if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
115 goto badframe;
116
117 set_current_blocked(&set);
118
119 if (restore_sigcontext(&frame->uc.uc_mcontext, &er0))
120 goto badframe;
121
122 if (restore_altstack(&frame->uc.uc_stack))
123 goto badframe;
124
125 return er0;
126
127badframe:
128 force_sig(SIGSEGV, current);
129 return 0;
130}
131
132static int setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs,
133 unsigned long mask)
134{
135 int err = 0;
136
137 err |= __put_user(regs->er0, &sc->sc_er0);
138 err |= __put_user(regs->er1, &sc->sc_er1);
139 err |= __put_user(regs->er2, &sc->sc_er2);
140 err |= __put_user(regs->er3, &sc->sc_er3);
141 err |= __put_user(regs->er4, &sc->sc_er4);
142 err |= __put_user(regs->er5, &sc->sc_er5);
143 err |= __put_user(regs->er6, &sc->sc_er6);
144 err |= __put_user(rdusp(), &sc->sc_usp);
145 err |= __put_user(regs->pc, &sc->sc_pc);
146 err |= __put_user(regs->ccr, &sc->sc_ccr);
147 err |= __put_user(mask, &sc->sc_mask);
148
149 return err;
150}
151
152static inline void __user *
153get_sigframe(struct ksignal *ksig, struct pt_regs *regs, size_t frame_size)
154{
155 return (void __user *)((sigsp(rdusp(), ksig) - frame_size) & -8UL);
156}
157
158static int setup_rt_frame(struct ksignal *ksig, sigset_t *set,
159 struct pt_regs *regs)
160{
161 struct rt_sigframe *frame;
162 int err = 0;
163 unsigned char *ret;
164
165 frame = get_sigframe(ksig, regs, sizeof(*frame));
166
167 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
168 return -EFAULT;
169
170 if (ksig->ka.sa.sa_flags & SA_SIGINFO)
171 err |= copy_siginfo_to_user(&frame->info, &ksig->info);
172
173 /* Create the ucontext. */
174 err |= __put_user(0, &frame->uc.uc_flags);
175 err |= __put_user(0, &frame->uc.uc_link);
176 err |= __save_altstack(&frame->uc.uc_stack, rdusp());
177 err |= setup_sigcontext(&frame->uc.uc_mcontext, regs, set->sig[0]);
178 err |= copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
179 if (err)
180 return -EFAULT;
181
182 /* Set up to return from userspace. */
183 ret = (unsigned char *)&frame->retcode;
184 if (ksig->ka.sa.sa_flags & SA_RESTORER)
185 ret = (unsigned char *)(ksig->ka.sa.sa_restorer);
186 else {
187 /* sub.l er0,er0; mov.b #__NR_rt_sigreturn,r0l; trapa #0 */
188 err |= __put_user(0x1a80f800 + (__NR_rt_sigreturn & 0xff),
189 (unsigned long *)(frame->retcode + 0));
190 err |= __put_user(0x5700,
191 (unsigned short *)(frame->retcode + 4));
192 }
193 err |= __put_user(ret, &frame->pretcode);
194
195 if (err)
196 return -EFAULT;
197
198 /* Set up registers for signal handler */
199 regs->sp = (unsigned long)frame;
200 regs->pc = (unsigned long)ksig->ka.sa.sa_handler;
201 regs->er0 = ksig->sig;
202 regs->er1 = (unsigned long)&(frame->info);
203 regs->er2 = (unsigned long)&frame->uc;
204 regs->er5 = current->mm->start_data; /* GOT base */
205
206 return 0;
207}
208
209static void
210handle_restart(struct pt_regs *regs, struct k_sigaction *ka)
211{
212 switch (regs->er0) {
213 case -ERESTARTNOHAND:
214 if (!ka)
215 goto do_restart;
216 regs->er0 = -EINTR;
217 break;
218 case -ERESTART_RESTARTBLOCK:
219 if (!ka) {
220 regs->er0 = __NR_restart_syscall;
221 regs->pc -= 2;
222 } else
223 regs->er0 = -EINTR;
224 break;
225 case -ERESTARTSYS:
226 if (!(ka->sa.sa_flags & SA_RESTART)) {
227 regs->er0 = -EINTR;
228 break;
229 }
230 /* fallthrough */
231 case -ERESTARTNOINTR:
232do_restart:
233 regs->er0 = regs->orig_er0;
234 regs->pc -= 2;
235 break;
236 }
237}
238
239/*
240 * OK, we're invoking a handler
241 */
242static void
243handle_signal(struct ksignal *ksig, struct pt_regs *regs)
244{
245 sigset_t *oldset = sigmask_to_save();
246 int ret;
247 /* are we from a system call? */
248 if (regs->orig_er0 >= 0)
249 handle_restart(regs, &ksig->ka);
250
251 ret = setup_rt_frame(ksig, oldset, regs);
252
253 signal_setup_done(ret, ksig, 0);
254}
255
256/*
257 * Note that 'init' is a special process: it doesn't get signals it doesn't
258 * want to handle. Thus you cannot kill init even with a SIGKILL even by
259 * mistake.
260 */
261static void do_signal(struct pt_regs *regs)
262{
263 struct ksignal ksig;
264
265 current->thread.esp0 = (unsigned long) regs;
266
267 if (get_signal(&ksig)) {
268 /* Whee! Actually deliver the signal. */
269 handle_signal(&ksig, regs);
270 return;
271 }
272 /* Did we come from a system call? */
273 if (regs->orig_er0 >= 0)
274 handle_restart(regs, NULL);
275
276 /* If there's no signal to deliver, we just restore the saved mask. */
277 restore_saved_sigmask();
278}
279
280asmlinkage void do_notify_resume(struct pt_regs *regs, u32 thread_info_flags)
281{
282 if (thread_info_flags & _TIF_SIGPENDING)
283 do_signal(regs);
284
285 if (thread_info_flags & _TIF_NOTIFY_RESUME) {
286 clear_thread_flag(TIF_NOTIFY_RESUME);
287 tracehook_notify_resume(regs);
288 }
289}