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/sched/task_stack.h>
29 #include <linux/mm.h>
30 #include <linux/kernel.h>
31 #include <linux/signal.h>
32 #include <linux/syscalls.h>
33 #include <linux/errno.h>
34 #include <linux/wait.h>
35 #include <linux/ptrace.h>
36 #include <linux/unistd.h>
37 #include <linux/stddef.h>
38 #include <linux/highuid.h>
39 #include <linux/personality.h>
40 #include <linux/tty.h>
41 #include <linux/binfmts.h>
42 #include <linux/tracehook.h>
43
44 #include <asm/setup.h>
45 #include <linux/uaccess.h>
46 #include <asm/pgtable.h>
47 #include <asm/traps.h>
48 #include <asm/ucontext.h>
49
50 /*
51 * Do a signal return; undo the signal stack.
52 *
53 * Keep the return code on the stack quadword aligned!
54 * That makes the cache flush below easier.
55 */
56
57 struct rt_sigframe {
58 long dummy_er0;
59 long dummy_vector;
60 #if defined(CONFIG_CPU_H8S)
61 short dummy_exr;
62 #endif
63 long dummy_pc;
64 char *pretcode;
65 struct siginfo *pinfo;
66 void *puc;
67 unsigned char retcode[8];
68 struct siginfo info;
69 struct ucontext uc;
70 int sig;
71 } __packed __aligned(2);
72
73 static inline int
74 restore_sigcontext(struct sigcontext *usc, int *pd0)
75 {
76 struct pt_regs *regs = current_pt_regs();
77 int err = 0;
78 unsigned int ccr;
79 unsigned int usp;
80 unsigned int er0;
81
82 /* Always make any pending restarted system calls return -EINTR */
83 current->restart_block.fn = do_no_restart_syscall;
84
85 /* restore passed registers */
86 #define COPY(r) do { err |= get_user(regs->r, &usc->sc_##r); } while (0)
87 COPY(er1);
88 COPY(er2);
89 COPY(er3);
90 COPY(er5);
91 COPY(pc);
92 ccr = regs->ccr & 0x10;
93 COPY(ccr);
94 #undef COPY
95 regs->ccr &= 0xef;
96 regs->ccr |= ccr;
97 regs->orig_er0 = -1; /* disable syscall checks */
98 err |= __get_user(usp, &usc->sc_usp);
99 regs->sp = usp;
100
101 err |= __get_user(er0, &usc->sc_er0);
102 *pd0 = er0;
103 return err;
104 }
105
106 asmlinkage int sys_rt_sigreturn(void)
107 {
108 unsigned long usp = rdusp();
109 struct rt_sigframe *frame = (struct rt_sigframe *)(usp - 4);
110 sigset_t set;
111 int er0;
112
113 if (!access_ok(frame, sizeof(*frame)))
114 goto badframe;
115 if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
116 goto badframe;
117
118 set_current_blocked(&set);
119
120 if (restore_sigcontext(&frame->uc.uc_mcontext, &er0))
121 goto badframe;
122
123 if (restore_altstack(&frame->uc.uc_stack))
124 goto badframe;
125
126 return er0;
127
128 badframe:
129 force_sig(SIGSEGV, current);
130 return 0;
131 }
132
133 static int setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs,
134 unsigned long mask)
135 {
136 int err = 0;
137
138 err |= __put_user(regs->er0, &sc->sc_er0);
139 err |= __put_user(regs->er1, &sc->sc_er1);
140 err |= __put_user(regs->er2, &sc->sc_er2);
141 err |= __put_user(regs->er3, &sc->sc_er3);
142 err |= __put_user(regs->er4, &sc->sc_er4);
143 err |= __put_user(regs->er5, &sc->sc_er5);
144 err |= __put_user(regs->er6, &sc->sc_er6);
145 err |= __put_user(rdusp(), &sc->sc_usp);
146 err |= __put_user(regs->pc, &sc->sc_pc);
147 err |= __put_user(regs->ccr, &sc->sc_ccr);
148 err |= __put_user(mask, &sc->sc_mask);
149
150 return err;
151 }
152
153 static inline void __user *
154 get_sigframe(struct ksignal *ksig, struct pt_regs *regs, size_t frame_size)
155 {
156 return (void __user *)((sigsp(rdusp(), ksig) - frame_size) & -8UL);
157 }
158
159 static int setup_rt_frame(struct ksignal *ksig, sigset_t *set,
160 struct pt_regs *regs)
161 {
162 struct rt_sigframe *frame;
163 int err = 0;
164 unsigned char *ret;
165
166 frame = get_sigframe(ksig, regs, sizeof(*frame));
167
168 if (!access_ok(frame, sizeof(*frame)))
169 return -EFAULT;
170
171 if (ksig->ka.sa.sa_flags & SA_SIGINFO)
172 err |= copy_siginfo_to_user(&frame->info, &ksig->info);
173
174 /* Create the ucontext. */
175 err |= __put_user(0, &frame->uc.uc_flags);
176 err |= __put_user(0, &frame->uc.uc_link);
177 err |= __save_altstack(&frame->uc.uc_stack, rdusp());
178 err |= setup_sigcontext(&frame->uc.uc_mcontext, regs, set->sig[0]);
179 err |= copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
180 if (err)
181 return -EFAULT;
182
183 /* Set up to return from userspace. */
184 ret = (unsigned char *)&frame->retcode;
185 if (ksig->ka.sa.sa_flags & SA_RESTORER)
186 ret = (unsigned char *)(ksig->ka.sa.sa_restorer);
187 else {
188 /* sub.l er0,er0; mov.b #__NR_rt_sigreturn,r0l; trapa #0 */
189 err |= __put_user(0x1a80f800 + (__NR_rt_sigreturn & 0xff),
190 (unsigned long *)(frame->retcode + 0));
191 err |= __put_user(0x5700,
192 (unsigned short *)(frame->retcode + 4));
193 }
194 err |= __put_user(ret, &frame->pretcode);
195
196 if (err)
197 return -EFAULT;
198
199 /* Set up registers for signal handler */
200 regs->sp = (unsigned long)frame;
201 regs->pc = (unsigned long)ksig->ka.sa.sa_handler;
202 regs->er0 = ksig->sig;
203 regs->er1 = (unsigned long)&(frame->info);
204 regs->er2 = (unsigned long)&frame->uc;
205 regs->er5 = current->mm->start_data; /* GOT base */
206
207 return 0;
208 }
209
210 static void
211 handle_restart(struct pt_regs *regs, struct k_sigaction *ka)
212 {
213 switch (regs->er0) {
214 case -ERESTARTNOHAND:
215 if (!ka)
216 goto do_restart;
217 regs->er0 = -EINTR;
218 break;
219 case -ERESTART_RESTARTBLOCK:
220 if (!ka) {
221 regs->er0 = __NR_restart_syscall;
222 regs->pc -= 2;
223 } else
224 regs->er0 = -EINTR;
225 break;
226 case -ERESTARTSYS:
227 if (!(ka->sa.sa_flags & SA_RESTART)) {
228 regs->er0 = -EINTR;
229 break;
230 }
231 /* fallthrough */
232 case -ERESTARTNOINTR:
233 do_restart:
234 regs->er0 = regs->orig_er0;
235 regs->pc -= 2;
236 break;
237 }
238 }
239
240 /*
241 * OK, we're invoking a handler
242 */
243 static void
244 handle_signal(struct ksignal *ksig, struct pt_regs *regs)
245 {
246 sigset_t *oldset = sigmask_to_save();
247 int ret;
248 /* are we from a system call? */
249 if (regs->orig_er0 >= 0)
250 handle_restart(regs, &ksig->ka);
251
252 ret = setup_rt_frame(ksig, oldset, regs);
253
254 signal_setup_done(ret, ksig, 0);
255 }
256
257 /*
258 * Note that 'init' is a special process: it doesn't get signals it doesn't
259 * want to handle. Thus you cannot kill init even with a SIGKILL even by
260 * mistake.
261 */
262 static void do_signal(struct pt_regs *regs)
263 {
264 struct ksignal ksig;
265
266 current->thread.esp0 = (unsigned long) regs;
267
268 if (get_signal(&ksig)) {
269 /* Whee! Actually deliver the signal. */
270 handle_signal(&ksig, regs);
271 return;
272 }
273 /* Did we come from a system call? */
274 if (regs->orig_er0 >= 0)
275 handle_restart(regs, NULL);
276
277 /* If there's no signal to deliver, we just restore the saved mask. */
278 restore_saved_sigmask();
279 }
280
281 asmlinkage void do_notify_resume(struct pt_regs *regs, u32 thread_info_flags)
282 {
283 if (thread_info_flags & _TIF_SIGPENDING)
284 do_signal(regs);
285
286 if (thread_info_flags & _TIF_NOTIFY_RESUME) {
287 clear_thread_flag(TIF_NOTIFY_RESUME);
288 tracehook_notify_resume(regs);
289 }
290 }
291
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