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1/* signal.c: FRV specific bits of signal handling
2 *
3 * Copyright (C) 2003-5 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells (dhowells@redhat.com)
5 * - Derived from arch/m68k/kernel/signal.c
6 *
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License
9 * as published by the Free Software Foundation; either version
10 * 2 of the License, or (at your option) any later version.
11 */
12
13#include <linux/sched.h>
14#include <linux/mm.h>
15#include <linux/smp.h>
16#include <linux/kernel.h>
17#include <linux/signal.h>
18#include <linux/errno.h>
19#include <linux/wait.h>
20#include <linux/ptrace.h>
21#include <linux/unistd.h>
22#include <linux/personality.h>
23#include <linux/freezer.h>
24#include <linux/tracehook.h>
25#include <asm/ucontext.h>
26#include <asm/uaccess.h>
27#include <asm/cacheflush.h>
28
29#define DEBUG_SIG 0
30
31struct fdpic_func_descriptor {
32 unsigned long text;
33 unsigned long GOT;
34};
35
36/*
37 * Atomically swap in the new signal mask, and wait for a signal.
38 */
39asmlinkage int sys_sigsuspend(int history0, int history1, old_sigset_t mask)
40{
41 sigset_t blocked;
42 siginitset(&blocked, mask);
43 return sigsuspend(&blocked);
44}
45
46asmlinkage int sys_sigaction(int sig,
47 const struct old_sigaction __user *act,
48 struct old_sigaction __user *oact)
49{
50 struct k_sigaction new_ka, old_ka;
51 int ret;
52
53 if (act) {
54 old_sigset_t mask;
55 if (!access_ok(VERIFY_READ, act, sizeof(*act)) ||
56 __get_user(new_ka.sa.sa_handler, &act->sa_handler) ||
57 __get_user(new_ka.sa.sa_restorer, &act->sa_restorer) ||
58 __get_user(new_ka.sa.sa_flags, &act->sa_flags) ||
59 __get_user(mask, &act->sa_mask))
60 return -EFAULT;
61 siginitset(&new_ka.sa.sa_mask, mask);
62 }
63
64 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
65
66 if (!ret && oact) {
67 if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) ||
68 __put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||
69 __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer) ||
70 __put_user(old_ka.sa.sa_flags, &oact->sa_flags) ||
71 __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask))
72 return -EFAULT;
73 }
74
75 return ret;
76}
77
78asmlinkage
79int sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss)
80{
81 return do_sigaltstack(uss, uoss, __frame->sp);
82}
83
84
85/*
86 * Do a signal return; undo the signal stack.
87 */
88
89struct sigframe
90{
91 __sigrestore_t pretcode;
92 int sig;
93 struct sigcontext sc;
94 unsigned long extramask[_NSIG_WORDS-1];
95 uint32_t retcode[2];
96};
97
98struct rt_sigframe
99{
100 __sigrestore_t pretcode;
101 int sig;
102 struct siginfo __user *pinfo;
103 void __user *puc;
104 struct siginfo info;
105 struct ucontext uc;
106 uint32_t retcode[2];
107};
108
109static int restore_sigcontext(struct sigcontext __user *sc, int *_gr8)
110{
111 struct user_context *user = current->thread.user;
112 unsigned long tbr, psr;
113
114 /* Always make any pending restarted system calls return -EINTR */
115 current_thread_info()->restart_block.fn = do_no_restart_syscall;
116
117 tbr = user->i.tbr;
118 psr = user->i.psr;
119 if (copy_from_user(user, &sc->sc_context, sizeof(sc->sc_context)))
120 goto badframe;
121 user->i.tbr = tbr;
122 user->i.psr = psr;
123
124 restore_user_regs(user);
125
126 user->i.syscallno = -1; /* disable syscall checks */
127
128 *_gr8 = user->i.gr[8];
129 return 0;
130
131 badframe:
132 return 1;
133}
134
135asmlinkage int sys_sigreturn(void)
136{
137 struct sigframe __user *frame = (struct sigframe __user *) __frame->sp;
138 sigset_t set;
139 int gr8;
140
141 if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
142 goto badframe;
143 if (__get_user(set.sig[0], &frame->sc.sc_oldmask))
144 goto badframe;
145
146 if (_NSIG_WORDS > 1 &&
147 __copy_from_user(&set.sig[1], &frame->extramask, sizeof(frame->extramask)))
148 goto badframe;
149
150 set_current_blocked(&set);
151
152 if (restore_sigcontext(&frame->sc, &gr8))
153 goto badframe;
154 return gr8;
155
156 badframe:
157 force_sig(SIGSEGV, current);
158 return 0;
159}
160
161asmlinkage int sys_rt_sigreturn(void)
162{
163 struct rt_sigframe __user *frame = (struct rt_sigframe __user *) __frame->sp;
164 sigset_t set;
165 int gr8;
166
167 if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
168 goto badframe;
169 if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
170 goto badframe;
171
172 set_current_blocked(&set);
173
174 if (restore_sigcontext(&frame->uc.uc_mcontext, &gr8))
175 goto badframe;
176
177 if (do_sigaltstack(&frame->uc.uc_stack, NULL, __frame->sp) == -EFAULT)
178 goto badframe;
179
180 return gr8;
181
182badframe:
183 force_sig(SIGSEGV, current);
184 return 0;
185}
186
187/*
188 * Set up a signal frame
189 */
190static int setup_sigcontext(struct sigcontext __user *sc, unsigned long mask)
191{
192 save_user_regs(current->thread.user);
193
194 if (copy_to_user(&sc->sc_context, current->thread.user, sizeof(sc->sc_context)) != 0)
195 goto badframe;
196
197 /* non-iBCS2 extensions.. */
198 if (__put_user(mask, &sc->sc_oldmask) < 0)
199 goto badframe;
200
201 return 0;
202
203 badframe:
204 return 1;
205}
206
207/*****************************************************************************/
208/*
209 * Determine which stack to use..
210 */
211static inline void __user *get_sigframe(struct k_sigaction *ka,
212 size_t frame_size)
213{
214 unsigned long sp;
215
216 /* Default to using normal stack */
217 sp = __frame->sp;
218
219 /* This is the X/Open sanctioned signal stack switching. */
220 if (ka->sa.sa_flags & SA_ONSTACK) {
221 if (! sas_ss_flags(sp))
222 sp = current->sas_ss_sp + current->sas_ss_size;
223 }
224
225 return (void __user *) ((sp - frame_size) & ~7UL);
226
227} /* end get_sigframe() */
228
229/*****************************************************************************/
230/*
231 *
232 */
233static int setup_frame(int sig, struct k_sigaction *ka, sigset_t *set)
234{
235 struct sigframe __user *frame;
236 int rsig;
237
238 set_fs(USER_DS);
239
240 frame = get_sigframe(ka, sizeof(*frame));
241
242 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
243 goto give_sigsegv;
244
245 rsig = sig;
246 if (sig < 32 &&
247 __current_thread_info->exec_domain &&
248 __current_thread_info->exec_domain->signal_invmap)
249 rsig = __current_thread_info->exec_domain->signal_invmap[sig];
250
251 if (__put_user(rsig, &frame->sig) < 0)
252 goto give_sigsegv;
253
254 if (setup_sigcontext(&frame->sc, set->sig[0]))
255 goto give_sigsegv;
256
257 if (_NSIG_WORDS > 1) {
258 if (__copy_to_user(frame->extramask, &set->sig[1],
259 sizeof(frame->extramask)))
260 goto give_sigsegv;
261 }
262
263 /* Set up to return from userspace. If provided, use a stub
264 * already in userspace. */
265 if (ka->sa.sa_flags & SA_RESTORER) {
266 if (__put_user(ka->sa.sa_restorer, &frame->pretcode) < 0)
267 goto give_sigsegv;
268 }
269 else {
270 /* Set up the following code on the stack:
271 * setlos #__NR_sigreturn,gr7
272 * tira gr0,0
273 */
274 if (__put_user((__sigrestore_t)frame->retcode, &frame->pretcode) ||
275 __put_user(0x8efc0000|__NR_sigreturn, &frame->retcode[0]) ||
276 __put_user(0xc0700000, &frame->retcode[1]))
277 goto give_sigsegv;
278
279 flush_icache_range((unsigned long) frame->retcode,
280 (unsigned long) (frame->retcode + 2));
281 }
282
283 /* Set up registers for the signal handler */
284 if (current->personality & FDPIC_FUNCPTRS) {
285 struct fdpic_func_descriptor __user *funcptr =
286 (struct fdpic_func_descriptor __user *) ka->sa.sa_handler;
287 struct fdpic_func_descriptor desc;
288 if (copy_from_user(&desc, funcptr, sizeof(desc)))
289 goto give_sigsegv;
290 __frame->pc = desc.text;
291 __frame->gr15 = desc.GOT;
292 } else {
293 __frame->pc = (unsigned long) ka->sa.sa_handler;
294 __frame->gr15 = 0;
295 }
296
297 __frame->sp = (unsigned long) frame;
298 __frame->lr = (unsigned long) &frame->retcode;
299 __frame->gr8 = sig;
300
301 /* the tracer may want to single-step inside the handler */
302 if (test_thread_flag(TIF_SINGLESTEP))
303 ptrace_notify(SIGTRAP);
304
305#if DEBUG_SIG
306 printk("SIG deliver %d (%s:%d): sp=%p pc=%lx ra=%p\n",
307 sig, current->comm, current->pid, frame, __frame->pc,
308 frame->pretcode);
309#endif
310
311 return 0;
312
313give_sigsegv:
314 force_sigsegv(sig, current);
315 return -EFAULT;
316
317} /* end setup_frame() */
318
319/*****************************************************************************/
320/*
321 *
322 */
323static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
324 sigset_t *set)
325{
326 struct rt_sigframe __user *frame;
327 int rsig;
328
329 set_fs(USER_DS);
330
331 frame = get_sigframe(ka, sizeof(*frame));
332
333 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
334 goto give_sigsegv;
335
336 rsig = sig;
337 if (sig < 32 &&
338 __current_thread_info->exec_domain &&
339 __current_thread_info->exec_domain->signal_invmap)
340 rsig = __current_thread_info->exec_domain->signal_invmap[sig];
341
342 if (__put_user(rsig, &frame->sig) ||
343 __put_user(&frame->info, &frame->pinfo) ||
344 __put_user(&frame->uc, &frame->puc))
345 goto give_sigsegv;
346
347 if (copy_siginfo_to_user(&frame->info, info))
348 goto give_sigsegv;
349
350 /* Create the ucontext. */
351 if (__put_user(0, &frame->uc.uc_flags) ||
352 __put_user(NULL, &frame->uc.uc_link) ||
353 __put_user((void __user *)current->sas_ss_sp, &frame->uc.uc_stack.ss_sp) ||
354 __put_user(sas_ss_flags(__frame->sp), &frame->uc.uc_stack.ss_flags) ||
355 __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size))
356 goto give_sigsegv;
357
358 if (setup_sigcontext(&frame->uc.uc_mcontext, set->sig[0]))
359 goto give_sigsegv;
360
361 if (__copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)))
362 goto give_sigsegv;
363
364 /* Set up to return from userspace. If provided, use a stub
365 * already in userspace. */
366 if (ka->sa.sa_flags & SA_RESTORER) {
367 if (__put_user(ka->sa.sa_restorer, &frame->pretcode))
368 goto give_sigsegv;
369 }
370 else {
371 /* Set up the following code on the stack:
372 * setlos #__NR_sigreturn,gr7
373 * tira gr0,0
374 */
375 if (__put_user((__sigrestore_t)frame->retcode, &frame->pretcode) ||
376 __put_user(0x8efc0000|__NR_rt_sigreturn, &frame->retcode[0]) ||
377 __put_user(0xc0700000, &frame->retcode[1]))
378 goto give_sigsegv;
379
380 flush_icache_range((unsigned long) frame->retcode,
381 (unsigned long) (frame->retcode + 2));
382 }
383
384 /* Set up registers for signal handler */
385 if (current->personality & FDPIC_FUNCPTRS) {
386 struct fdpic_func_descriptor __user *funcptr =
387 (struct fdpic_func_descriptor __user *) ka->sa.sa_handler;
388 struct fdpic_func_descriptor desc;
389 if (copy_from_user(&desc, funcptr, sizeof(desc)))
390 goto give_sigsegv;
391 __frame->pc = desc.text;
392 __frame->gr15 = desc.GOT;
393 } else {
394 __frame->pc = (unsigned long) ka->sa.sa_handler;
395 __frame->gr15 = 0;
396 }
397
398 __frame->sp = (unsigned long) frame;
399 __frame->lr = (unsigned long) &frame->retcode;
400 __frame->gr8 = sig;
401 __frame->gr9 = (unsigned long) &frame->info;
402
403 /* the tracer may want to single-step inside the handler */
404 if (test_thread_flag(TIF_SINGLESTEP))
405 ptrace_notify(SIGTRAP);
406
407#if DEBUG_SIG
408 printk("SIG deliver %d (%s:%d): sp=%p pc=%lx ra=%p\n",
409 sig, current->comm, current->pid, frame, __frame->pc,
410 frame->pretcode);
411#endif
412
413 return 0;
414
415give_sigsegv:
416 force_sigsegv(sig, current);
417 return -EFAULT;
418
419} /* end setup_rt_frame() */
420
421/*****************************************************************************/
422/*
423 * OK, we're invoking a handler
424 */
425static void handle_signal(unsigned long sig, siginfo_t *info,
426 struct k_sigaction *ka)
427{
428 sigset_t *oldset = sigmask_to_save();
429 int ret;
430
431 /* Are we from a system call? */
432 if (__frame->syscallno != -1) {
433 /* If so, check system call restarting.. */
434 switch (__frame->gr8) {
435 case -ERESTART_RESTARTBLOCK:
436 case -ERESTARTNOHAND:
437 __frame->gr8 = -EINTR;
438 break;
439
440 case -ERESTARTSYS:
441 if (!(ka->sa.sa_flags & SA_RESTART)) {
442 __frame->gr8 = -EINTR;
443 break;
444 }
445
446 /* fallthrough */
447 case -ERESTARTNOINTR:
448 __frame->gr8 = __frame->orig_gr8;
449 __frame->pc -= 4;
450 }
451 __frame->syscallno = -1;
452 }
453
454 /* Set up the stack frame */
455 if (ka->sa.sa_flags & SA_SIGINFO)
456 ret = setup_rt_frame(sig, ka, info, oldset);
457 else
458 ret = setup_frame(sig, ka, oldset);
459
460 if (ret)
461 return;
462
463 signal_delivered(sig, info, ka, __frame,
464 test_thread_flag(TIF_SINGLESTEP));
465} /* end handle_signal() */
466
467/*****************************************************************************/
468/*
469 * Note that 'init' is a special process: it doesn't get signals it doesn't
470 * want to handle. Thus you cannot kill init even with a SIGKILL even by
471 * mistake.
472 */
473static void do_signal(void)
474{
475 struct k_sigaction ka;
476 siginfo_t info;
477 int signr;
478
479 signr = get_signal_to_deliver(&info, &ka, __frame, NULL);
480 if (signr > 0) {
481 handle_signal(signr, &info, &ka);
482 return;
483 }
484
485 /* Did we come from a system call? */
486 if (__frame->syscallno != -1) {
487 /* Restart the system call - no handlers present */
488 switch (__frame->gr8) {
489 case -ERESTARTNOHAND:
490 case -ERESTARTSYS:
491 case -ERESTARTNOINTR:
492 __frame->gr8 = __frame->orig_gr8;
493 __frame->pc -= 4;
494 break;
495
496 case -ERESTART_RESTARTBLOCK:
497 __frame->gr7 = __NR_restart_syscall;
498 __frame->pc -= 4;
499 break;
500 }
501 __frame->syscallno = -1;
502 }
503
504 /* if there's no signal to deliver, we just put the saved sigmask
505 * back */
506 restore_saved_sigmask();
507} /* end do_signal() */
508
509/*****************************************************************************/
510/*
511 * notification of userspace execution resumption
512 * - triggered by the TIF_WORK_MASK flags
513 */
514asmlinkage void do_notify_resume(__u32 thread_info_flags)
515{
516 /* pending single-step? */
517 if (thread_info_flags & _TIF_SINGLESTEP)
518 clear_thread_flag(TIF_SINGLESTEP);
519
520 /* deal with pending signal delivery */
521 if (thread_info_flags & _TIF_SIGPENDING)
522 do_signal();
523
524 /* deal with notification on about to resume userspace execution */
525 if (thread_info_flags & _TIF_NOTIFY_RESUME) {
526 clear_thread_flag(TIF_NOTIFY_RESUME);
527 tracehook_notify_resume(__frame);
528 }
529
530} /* end do_notify_resume() */