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_thread_info()->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 k_sigaction * ka,struct pt_regs * regs,size_t frame_size)189 static inline void __user *get_sigframe(struct k_sigaction *ka,
190 struct pt_regs *regs,
191 size_t frame_size)
192 {
193 unsigned long sp;
194
195 /* default to using normal stack */
196 sp = regs->sp;
197
198 /* this is the X/Open sanctioned signal stack switching. */
199 if (ka->sa.sa_flags & SA_ONSTACK) {
200 if (sas_ss_flags(sp) == 0)
201 sp = current->sas_ss_sp + current->sas_ss_size;
202 }
203
204 return (void __user *) ((sp - frame_size) & ~7UL);
205 }
206
207 /*
208 * set up a normal signal frame
209 */
setup_frame(int sig,struct k_sigaction * ka,sigset_t * set,struct pt_regs * regs)210 static int setup_frame(int sig, struct k_sigaction *ka, sigset_t *set,
211 struct pt_regs *regs)
212 {
213 struct sigframe __user *frame;
214 int rsig;
215
216 frame = get_sigframe(ka, regs, sizeof(*frame));
217
218 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
219 goto give_sigsegv;
220
221 rsig = sig;
222 if (sig < 32 &&
223 current_thread_info()->exec_domain &&
224 current_thread_info()->exec_domain->signal_invmap)
225 rsig = current_thread_info()->exec_domain->signal_invmap[sig];
226
227 if (__put_user(rsig, &frame->sig) < 0 ||
228 __put_user(&frame->sc, &frame->psc) < 0)
229 goto give_sigsegv;
230
231 if (setup_sigcontext(&frame->sc, &frame->fpuctx, regs, set->sig[0]))
232 goto give_sigsegv;
233
234 if (_NSIG_WORDS > 1) {
235 if (__copy_to_user(frame->extramask, &set->sig[1],
236 sizeof(frame->extramask)))
237 goto give_sigsegv;
238 }
239
240 /* set up to return from userspace. If provided, use a stub already in
241 * userspace */
242 if (ka->sa.sa_flags & SA_RESTORER) {
243 if (__put_user(ka->sa.sa_restorer, &frame->pretcode))
244 goto give_sigsegv;
245 } else {
246 if (__put_user((void (*)(void))frame->retcode,
247 &frame->pretcode))
248 goto give_sigsegv;
249 /* this is mov $,d0; syscall 0 */
250 if (__put_user(0x2c, (char *)(frame->retcode + 0)) ||
251 __put_user(__NR_sigreturn, (char *)(frame->retcode + 1)) ||
252 __put_user(0x00, (char *)(frame->retcode + 2)) ||
253 __put_user(0xf0, (char *)(frame->retcode + 3)) ||
254 __put_user(0xe0, (char *)(frame->retcode + 4)))
255 goto give_sigsegv;
256 flush_icache_range((unsigned long) frame->retcode,
257 (unsigned long) frame->retcode + 5);
258 }
259
260 /* set up registers for signal handler */
261 regs->sp = (unsigned long) frame;
262 regs->pc = (unsigned long) ka->sa.sa_handler;
263 regs->d0 = sig;
264 regs->d1 = (unsigned long) &frame->sc;
265
266 #if DEBUG_SIG
267 printk(KERN_DEBUG "SIG deliver %d (%s:%d): sp=%p pc=%lx ra=%p\n",
268 sig, current->comm, current->pid, frame, regs->pc,
269 frame->pretcode);
270 #endif
271
272 return 0;
273
274 give_sigsegv:
275 force_sigsegv(sig, current);
276 return -EFAULT;
277 }
278
279 /*
280 * set up a realtime signal frame
281 */
setup_rt_frame(int sig,struct k_sigaction * ka,siginfo_t * info,sigset_t * set,struct pt_regs * regs)282 static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
283 sigset_t *set, struct pt_regs *regs)
284 {
285 struct rt_sigframe __user *frame;
286 int rsig;
287
288 frame = get_sigframe(ka, regs, sizeof(*frame));
289
290 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
291 goto give_sigsegv;
292
293 rsig = sig;
294 if (sig < 32 &&
295 current_thread_info()->exec_domain &&
296 current_thread_info()->exec_domain->signal_invmap)
297 rsig = current_thread_info()->exec_domain->signal_invmap[sig];
298
299 if (__put_user(rsig, &frame->sig) ||
300 __put_user(&frame->info, &frame->pinfo) ||
301 __put_user(&frame->uc, &frame->puc) ||
302 copy_siginfo_to_user(&frame->info, info))
303 goto give_sigsegv;
304
305 /* create the ucontext. */
306 if (__put_user(0, &frame->uc.uc_flags) ||
307 __put_user(0, &frame->uc.uc_link) ||
308 __save_altstack(&frame->uc.uc_stack, regs->sp) ||
309 setup_sigcontext(&frame->uc.uc_mcontext,
310 &frame->fpuctx, regs, set->sig[0]) ||
311 __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)))
312 goto give_sigsegv;
313
314 /* set up to return from userspace. If provided, use a stub already in
315 * userspace */
316 if (ka->sa.sa_flags & SA_RESTORER) {
317 if (__put_user(ka->sa.sa_restorer, &frame->pretcode))
318 goto give_sigsegv;
319 } else {
320 if (__put_user((void(*)(void))frame->retcode,
321 &frame->pretcode) ||
322 /* This is mov $,d0; syscall 0 */
323 __put_user(0x2c, (char *)(frame->retcode + 0)) ||
324 __put_user(__NR_rt_sigreturn,
325 (char *)(frame->retcode + 1)) ||
326 __put_user(0x00, (char *)(frame->retcode + 2)) ||
327 __put_user(0xf0, (char *)(frame->retcode + 3)) ||
328 __put_user(0xe0, (char *)(frame->retcode + 4)))
329 goto give_sigsegv;
330
331 flush_icache_range((u_long) frame->retcode,
332 (u_long) frame->retcode + 5);
333 }
334
335 /* Set up registers for signal handler */
336 regs->sp = (unsigned long) frame;
337 regs->pc = (unsigned long) ka->sa.sa_handler;
338 regs->d0 = sig;
339 regs->d1 = (long) &frame->info;
340
341 #if DEBUG_SIG
342 printk(KERN_DEBUG "SIG deliver %d (%s:%d): sp=%p pc=%lx ra=%p\n",
343 sig, current->comm, current->pid, frame, regs->pc,
344 frame->pretcode);
345 #endif
346
347 return 0;
348
349 give_sigsegv:
350 force_sigsegv(sig, current);
351 return -EFAULT;
352 }
353
stepback(struct pt_regs * regs)354 static inline void stepback(struct pt_regs *regs)
355 {
356 regs->pc -= 2;
357 regs->orig_d0 = -1;
358 }
359
360 /*
361 * handle the actual delivery of a signal to userspace
362 */
handle_signal(int sig,siginfo_t * info,struct k_sigaction * ka,struct pt_regs * regs)363 static int handle_signal(int sig,
364 siginfo_t *info, struct k_sigaction *ka,
365 struct pt_regs *regs)
366 {
367 sigset_t *oldset = sigmask_to_save();
368 int ret;
369
370 /* Are we from a system call? */
371 if (regs->orig_d0 >= 0) {
372 /* If so, check system call restarting.. */
373 switch (regs->d0) {
374 case -ERESTART_RESTARTBLOCK:
375 case -ERESTARTNOHAND:
376 regs->d0 = -EINTR;
377 break;
378
379 case -ERESTARTSYS:
380 if (!(ka->sa.sa_flags & SA_RESTART)) {
381 regs->d0 = -EINTR;
382 break;
383 }
384
385 /* fallthrough */
386 case -ERESTARTNOINTR:
387 regs->d0 = regs->orig_d0;
388 stepback(regs);
389 }
390 }
391
392 /* Set up the stack frame */
393 if (ka->sa.sa_flags & SA_SIGINFO)
394 ret = setup_rt_frame(sig, ka, info, oldset, regs);
395 else
396 ret = setup_frame(sig, ka, oldset, regs);
397 if (ret)
398 return ret;
399
400 signal_delivered(sig, info, ka, regs,
401 test_thread_flag(TIF_SINGLESTEP));
402 return 0;
403 }
404
405 /*
406 * handle a potential signal
407 */
do_signal(struct pt_regs * regs)408 static void do_signal(struct pt_regs *regs)
409 {
410 struct k_sigaction ka;
411 siginfo_t info;
412 int signr;
413
414 signr = get_signal_to_deliver(&info, &ka, regs, NULL);
415 if (signr > 0) {
416 if (handle_signal(signr, &info, &ka, regs) == 0) {
417 }
418
419 return;
420 }
421
422 /* did we come from a system call? */
423 if (regs->orig_d0 >= 0) {
424 /* restart the system call - no handlers present */
425 switch (regs->d0) {
426 case -ERESTARTNOHAND:
427 case -ERESTARTSYS:
428 case -ERESTARTNOINTR:
429 regs->d0 = regs->orig_d0;
430 stepback(regs);
431 break;
432
433 case -ERESTART_RESTARTBLOCK:
434 regs->d0 = __NR_restart_syscall;
435 stepback(regs);
436 break;
437 }
438 }
439
440 /* if there's no signal to deliver, we just put the saved sigmask
441 * back */
442 restore_saved_sigmask();
443 }
444
445 /*
446 * notification of userspace execution resumption
447 * - triggered by current->work.notify_resume
448 */
do_notify_resume(struct pt_regs * regs,u32 thread_info_flags)449 asmlinkage void do_notify_resume(struct pt_regs *regs, u32 thread_info_flags)
450 {
451 /* Pending single-step? */
452 if (thread_info_flags & _TIF_SINGLESTEP) {
453 #ifndef CONFIG_MN10300_USING_JTAG
454 regs->epsw |= EPSW_T;
455 clear_thread_flag(TIF_SINGLESTEP);
456 #else
457 BUG(); /* no h/w single-step if using JTAG unit */
458 #endif
459 }
460
461 /* deal with pending signal delivery */
462 if (thread_info_flags & _TIF_SIGPENDING)
463 do_signal(regs);
464
465 if (thread_info_flags & _TIF_NOTIFY_RESUME) {
466 clear_thread_flag(TIF_NOTIFY_RESUME);
467 tracehook_notify_resume(current_frame());
468 }
469 }
470