1 /* MN10300 Signal handling
2 *
3 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells (dhowells@redhat.com)
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public Licence
8 * as published by the Free Software Foundation; either version
9 * 2 of the Licence, or (at your option) any later version.
10 */
11
12 #include <linux/sched.h>
13 #include <linux/mm.h>
14 #include <linux/smp.h>
15 #include <linux/kernel.h>
16 #include <linux/signal.h>
17 #include <linux/errno.h>
18 #include <linux/wait.h>
19 #include <linux/ptrace.h>
20 #include <linux/unistd.h>
21 #include <linux/stddef.h>
22 #include <linux/tty.h>
23 #include <linux/personality.h>
24 #include <linux/suspend.h>
25 #include <linux/tracehook.h>
26 #include <asm/cacheflush.h>
27 #include <asm/ucontext.h>
28 #include <asm/uaccess.h>
29 #include <asm/fpu.h>
30 #include "sigframe.h"
31
32 #define DEBUG_SIG 0
33
34 /*
35 * do a signal return; undo the signal stack.
36 */
restore_sigcontext(struct pt_regs * regs,struct sigcontext __user * sc,long * _d0)37 static int restore_sigcontext(struct pt_regs *regs,
38 struct sigcontext __user *sc, long *_d0)
39 {
40 unsigned int err = 0;
41
42 /* Always make any pending restarted system calls return -EINTR */
43 current->restart_block.fn = do_no_restart_syscall;
44
45 if (is_using_fpu(current))
46 fpu_kill_state(current);
47
48 #define COPY(x) err |= __get_user(regs->x, &sc->x)
49 COPY(d1); COPY(d2); COPY(d3);
50 COPY(a0); COPY(a1); COPY(a2); COPY(a3);
51 COPY(e0); COPY(e1); COPY(e2); COPY(e3);
52 COPY(e4); COPY(e5); COPY(e6); COPY(e7);
53 COPY(lar); COPY(lir);
54 COPY(mdr); COPY(mdrq);
55 COPY(mcvf); COPY(mcrl); COPY(mcrh);
56 COPY(sp); COPY(pc);
57 #undef COPY
58
59 {
60 unsigned int tmpflags;
61 #ifndef CONFIG_MN10300_USING_JTAG
62 #define USER_EPSW (EPSW_FLAG_Z | EPSW_FLAG_N | EPSW_FLAG_C | EPSW_FLAG_V | \
63 EPSW_T | EPSW_nAR)
64 #else
65 #define USER_EPSW (EPSW_FLAG_Z | EPSW_FLAG_N | EPSW_FLAG_C | EPSW_FLAG_V | \
66 EPSW_nAR)
67 #endif
68 err |= __get_user(tmpflags, &sc->epsw);
69 regs->epsw = (regs->epsw & ~USER_EPSW) |
70 (tmpflags & USER_EPSW);
71 regs->orig_d0 = -1; /* disable syscall checks */
72 }
73
74 {
75 struct fpucontext *buf;
76 err |= __get_user(buf, &sc->fpucontext);
77 if (buf) {
78 if (verify_area(VERIFY_READ, buf, sizeof(*buf)))
79 goto badframe;
80 err |= fpu_restore_sigcontext(buf);
81 }
82 }
83
84 err |= __get_user(*_d0, &sc->d0);
85 return err;
86
87 badframe:
88 return 1;
89 }
90
91 /*
92 * standard signal return syscall
93 */
sys_sigreturn(void)94 asmlinkage long sys_sigreturn(void)
95 {
96 struct sigframe __user *frame;
97 sigset_t set;
98 long d0;
99
100 frame = (struct sigframe __user *) current_frame()->sp;
101 if (verify_area(VERIFY_READ, frame, sizeof(*frame)))
102 goto badframe;
103 if (__get_user(set.sig[0], &frame->sc.oldmask))
104 goto badframe;
105
106 if (_NSIG_WORDS > 1 &&
107 __copy_from_user(&set.sig[1], &frame->extramask,
108 sizeof(frame->extramask)))
109 goto badframe;
110
111 set_current_blocked(&set);
112
113 if (restore_sigcontext(current_frame(), &frame->sc, &d0))
114 goto badframe;
115
116 return d0;
117
118 badframe:
119 force_sig(SIGSEGV, current);
120 return 0;
121 }
122
123 /*
124 * realtime signal return syscall
125 */
sys_rt_sigreturn(void)126 asmlinkage long sys_rt_sigreturn(void)
127 {
128 struct rt_sigframe __user *frame;
129 sigset_t set;
130 long d0;
131
132 frame = (struct rt_sigframe __user *) current_frame()->sp;
133 if (verify_area(VERIFY_READ, frame, sizeof(*frame)))
134 goto badframe;
135 if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
136 goto badframe;
137
138 set_current_blocked(&set);
139
140 if (restore_sigcontext(current_frame(), &frame->uc.uc_mcontext, &d0))
141 goto badframe;
142
143 if (restore_altstack(&frame->uc.uc_stack))
144 goto badframe;
145
146 return d0;
147
148 badframe:
149 force_sig(SIGSEGV, current);
150 return 0;
151 }
152
153 /*
154 * store the userspace context into a signal frame
155 */
setup_sigcontext(struct sigcontext __user * sc,struct fpucontext * fpuctx,struct pt_regs * regs,unsigned long mask)156 static int setup_sigcontext(struct sigcontext __user *sc,
157 struct fpucontext *fpuctx,
158 struct pt_regs *regs,
159 unsigned long mask)
160 {
161 int tmp, err = 0;
162
163 #define COPY(x) err |= __put_user(regs->x, &sc->x)
164 COPY(d0); COPY(d1); COPY(d2); COPY(d3);
165 COPY(a0); COPY(a1); COPY(a2); COPY(a3);
166 COPY(e0); COPY(e1); COPY(e2); COPY(e3);
167 COPY(e4); COPY(e5); COPY(e6); COPY(e7);
168 COPY(lar); COPY(lir);
169 COPY(mdr); COPY(mdrq);
170 COPY(mcvf); COPY(mcrl); COPY(mcrh);
171 COPY(sp); COPY(epsw); COPY(pc);
172 #undef COPY
173
174 tmp = fpu_setup_sigcontext(fpuctx);
175 if (tmp < 0)
176 err = 1;
177 else
178 err |= __put_user(tmp ? fpuctx : NULL, &sc->fpucontext);
179
180 /* non-iBCS2 extensions.. */
181 err |= __put_user(mask, &sc->oldmask);
182
183 return err;
184 }
185
186 /*
187 * determine which stack to use..
188 */
get_sigframe(struct ksignal * ksig,struct pt_regs * regs,size_t frame_size)189 static inline void __user *get_sigframe(struct ksignal *ksig,
190 struct pt_regs *regs,
191 size_t frame_size)
192 {
193 unsigned long sp = sigsp(regs->sp, ksig);
194
195 return (void __user *) ((sp - frame_size) & ~7UL);
196 }
197
198 /*
199 * set up a normal signal frame
200 */
setup_frame(struct ksignal * ksig,sigset_t * set,struct pt_regs * regs)201 static int setup_frame(struct ksignal *ksig, sigset_t *set,
202 struct pt_regs *regs)
203 {
204 struct sigframe __user *frame;
205 int rsig, sig = ksig->sig;
206
207 frame = get_sigframe(ksig, regs, sizeof(*frame));
208
209 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
210 return -EFAULT;
211
212 rsig = sig;
213 if (sig < 32 &&
214 current_thread_info()->exec_domain &&
215 current_thread_info()->exec_domain->signal_invmap)
216 rsig = current_thread_info()->exec_domain->signal_invmap[sig];
217
218 if (__put_user(rsig, &frame->sig) < 0 ||
219 __put_user(&frame->sc, &frame->psc) < 0)
220 return -EFAULT;
221
222 if (setup_sigcontext(&frame->sc, &frame->fpuctx, regs, set->sig[0]))
223 return -EFAULT;
224
225 if (_NSIG_WORDS > 1) {
226 if (__copy_to_user(frame->extramask, &set->sig[1],
227 sizeof(frame->extramask)))
228 return -EFAULT;
229 }
230
231 /* set up to return from userspace. If provided, use a stub already in
232 * userspace */
233 if (ksig->ka.sa.sa_flags & SA_RESTORER) {
234 if (__put_user(ksig->ka.sa.sa_restorer, &frame->pretcode))
235 return -EFAULT;
236 } else {
237 if (__put_user((void (*)(void))frame->retcode,
238 &frame->pretcode))
239 return -EFAULT;
240 /* this is mov $,d0; syscall 0 */
241 if (__put_user(0x2c, (char *)(frame->retcode + 0)) ||
242 __put_user(__NR_sigreturn, (char *)(frame->retcode + 1)) ||
243 __put_user(0x00, (char *)(frame->retcode + 2)) ||
244 __put_user(0xf0, (char *)(frame->retcode + 3)) ||
245 __put_user(0xe0, (char *)(frame->retcode + 4)))
246 return -EFAULT;
247 flush_icache_range((unsigned long) frame->retcode,
248 (unsigned long) frame->retcode + 5);
249 }
250
251 /* set up registers for signal handler */
252 regs->sp = (unsigned long) frame;
253 regs->pc = (unsigned long) ksig->ka.sa.sa_handler;
254 regs->d0 = sig;
255 regs->d1 = (unsigned long) &frame->sc;
256
257 #if DEBUG_SIG
258 printk(KERN_DEBUG "SIG deliver %d (%s:%d): sp=%p pc=%lx ra=%p\n",
259 sig, current->comm, current->pid, frame, regs->pc,
260 frame->pretcode);
261 #endif
262
263 return 0;
264 }
265
266 /*
267 * set up a realtime signal frame
268 */
setup_rt_frame(struct ksignal * ksig,sigset_t * set,struct pt_regs * regs)269 static int setup_rt_frame(struct ksignal *ksig, sigset_t *set,
270 struct pt_regs *regs)
271 {
272 struct rt_sigframe __user *frame;
273 int rsig, sig = ksig->sig;
274
275 frame = get_sigframe(ksig, regs, sizeof(*frame));
276
277 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
278 return -EFAULT;
279
280 rsig = sig;
281 if (sig < 32 &&
282 current_thread_info()->exec_domain &&
283 current_thread_info()->exec_domain->signal_invmap)
284 rsig = current_thread_info()->exec_domain->signal_invmap[sig];
285
286 if (__put_user(rsig, &frame->sig) ||
287 __put_user(&frame->info, &frame->pinfo) ||
288 __put_user(&frame->uc, &frame->puc) ||
289 copy_siginfo_to_user(&frame->info, &ksig->info))
290 return -EFAULT;
291
292 /* create the ucontext. */
293 if (__put_user(0, &frame->uc.uc_flags) ||
294 __put_user(0, &frame->uc.uc_link) ||
295 __save_altstack(&frame->uc.uc_stack, regs->sp) ||
296 setup_sigcontext(&frame->uc.uc_mcontext,
297 &frame->fpuctx, regs, set->sig[0]) ||
298 __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)))
299 return -EFAULT;
300
301 /* set up to return from userspace. If provided, use a stub already in
302 * userspace */
303 if (ksig->ka.sa.sa_flags & SA_RESTORER) {
304 if (__put_user(ksig->ka.sa.sa_restorer, &frame->pretcode))
305 return -EFAULT;
306
307 } else {
308 if (__put_user((void(*)(void))frame->retcode,
309 &frame->pretcode) ||
310 /* This is mov $,d0; syscall 0 */
311 __put_user(0x2c, (char *)(frame->retcode + 0)) ||
312 __put_user(__NR_rt_sigreturn,
313 (char *)(frame->retcode + 1)) ||
314 __put_user(0x00, (char *)(frame->retcode + 2)) ||
315 __put_user(0xf0, (char *)(frame->retcode + 3)) ||
316 __put_user(0xe0, (char *)(frame->retcode + 4)))
317 return -EFAULT;
318
319 flush_icache_range((u_long) frame->retcode,
320 (u_long) frame->retcode + 5);
321 }
322
323 /* Set up registers for signal handler */
324 regs->sp = (unsigned long) frame;
325 regs->pc = (unsigned long) ksig->ka.sa.sa_handler;
326 regs->d0 = sig;
327 regs->d1 = (long) &frame->info;
328
329 #if DEBUG_SIG
330 printk(KERN_DEBUG "SIG deliver %d (%s:%d): sp=%p pc=%lx ra=%p\n",
331 sig, current->comm, current->pid, frame, regs->pc,
332 frame->pretcode);
333 #endif
334
335 return 0;
336 }
337
stepback(struct pt_regs * regs)338 static inline void stepback(struct pt_regs *regs)
339 {
340 regs->pc -= 2;
341 regs->orig_d0 = -1;
342 }
343
344 /*
345 * handle the actual delivery of a signal to userspace
346 */
handle_signal(struct ksignal * ksig,struct pt_regs * regs)347 static int handle_signal(struct ksignal *ksig, struct pt_regs *regs)
348 {
349 sigset_t *oldset = sigmask_to_save();
350 int ret;
351
352 /* Are we from a system call? */
353 if (regs->orig_d0 >= 0) {
354 /* If so, check system call restarting.. */
355 switch (regs->d0) {
356 case -ERESTART_RESTARTBLOCK:
357 case -ERESTARTNOHAND:
358 regs->d0 = -EINTR;
359 break;
360
361 case -ERESTARTSYS:
362 if (!(ksig->ka.sa.sa_flags & SA_RESTART)) {
363 regs->d0 = -EINTR;
364 break;
365 }
366
367 /* fallthrough */
368 case -ERESTARTNOINTR:
369 regs->d0 = regs->orig_d0;
370 stepback(regs);
371 }
372 }
373
374 /* Set up the stack frame */
375 if (ksig->ka.sa.sa_flags & SA_SIGINFO)
376 ret = setup_rt_frame(ksig, oldset, regs);
377 else
378 ret = setup_frame(ksig, oldset, regs);
379
380 signal_setup_done(ret, ksig, test_thread_flag(TIF_SINGLESTEP));
381 return 0;
382 }
383
384 /*
385 * handle a potential signal
386 */
do_signal(struct pt_regs * regs)387 static void do_signal(struct pt_regs *regs)
388 {
389 struct ksignal ksig;
390
391 if (get_signal(&ksig)) {
392 handle_signal(&ksig, regs);
393 return;
394 }
395
396 /* did we come from a system call? */
397 if (regs->orig_d0 >= 0) {
398 /* restart the system call - no handlers present */
399 switch (regs->d0) {
400 case -ERESTARTNOHAND:
401 case -ERESTARTSYS:
402 case -ERESTARTNOINTR:
403 regs->d0 = regs->orig_d0;
404 stepback(regs);
405 break;
406
407 case -ERESTART_RESTARTBLOCK:
408 regs->d0 = __NR_restart_syscall;
409 stepback(regs);
410 break;
411 }
412 }
413
414 /* if there's no signal to deliver, we just put the saved sigmask
415 * back */
416 restore_saved_sigmask();
417 }
418
419 /*
420 * notification of userspace execution resumption
421 * - triggered by current->work.notify_resume
422 */
do_notify_resume(struct pt_regs * regs,u32 thread_info_flags)423 asmlinkage void do_notify_resume(struct pt_regs *regs, u32 thread_info_flags)
424 {
425 /* Pending single-step? */
426 if (thread_info_flags & _TIF_SINGLESTEP) {
427 #ifndef CONFIG_MN10300_USING_JTAG
428 regs->epsw |= EPSW_T;
429 clear_thread_flag(TIF_SINGLESTEP);
430 #else
431 BUG(); /* no h/w single-step if using JTAG unit */
432 #endif
433 }
434
435 /* deal with pending signal delivery */
436 if (thread_info_flags & _TIF_SIGPENDING)
437 do_signal(regs);
438
439 if (thread_info_flags & _TIF_NOTIFY_RESUME) {
440 clear_thread_flag(TIF_NOTIFY_RESUME);
441 tracehook_notify_resume(current_frame());
442 }
443 }
444