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/tracehook.h>
24 #include <asm/ucontext.h>
25 #include <asm/uaccess.h>
26 #include <asm/cacheflush.h>
27
28 #define DEBUG_SIG 0
29
30 struct fdpic_func_descriptor {
31 unsigned long text;
32 unsigned long GOT;
33 };
34
35 /*
36 * Do a signal return; undo the signal stack.
37 */
38
39 struct sigframe
40 {
41 __sigrestore_t pretcode;
42 int sig;
43 struct sigcontext sc;
44 unsigned long extramask[_NSIG_WORDS-1];
45 uint32_t retcode[2];
46 };
47
48 struct rt_sigframe
49 {
50 __sigrestore_t pretcode;
51 int sig;
52 struct siginfo __user *pinfo;
53 void __user *puc;
54 struct siginfo info;
55 struct ucontext uc;
56 uint32_t retcode[2];
57 };
58
restore_sigcontext(struct sigcontext __user * sc,int * _gr8)59 static int restore_sigcontext(struct sigcontext __user *sc, int *_gr8)
60 {
61 struct user_context *user = current->thread.user;
62 unsigned long tbr, psr;
63
64 /* Always make any pending restarted system calls return -EINTR */
65 current->restart_block.fn = do_no_restart_syscall;
66
67 tbr = user->i.tbr;
68 psr = user->i.psr;
69 if (copy_from_user(user, &sc->sc_context, sizeof(sc->sc_context)))
70 goto badframe;
71 user->i.tbr = tbr;
72 user->i.psr = psr;
73
74 restore_user_regs(user);
75
76 user->i.syscallno = -1; /* disable syscall checks */
77
78 *_gr8 = user->i.gr[8];
79 return 0;
80
81 badframe:
82 return 1;
83 }
84
sys_sigreturn(void)85 asmlinkage int sys_sigreturn(void)
86 {
87 struct sigframe __user *frame = (struct sigframe __user *) __frame->sp;
88 sigset_t set;
89 int gr8;
90
91 if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
92 goto badframe;
93 if (__get_user(set.sig[0], &frame->sc.sc_oldmask))
94 goto badframe;
95
96 if (_NSIG_WORDS > 1 &&
97 __copy_from_user(&set.sig[1], &frame->extramask, sizeof(frame->extramask)))
98 goto badframe;
99
100 set_current_blocked(&set);
101
102 if (restore_sigcontext(&frame->sc, &gr8))
103 goto badframe;
104 return gr8;
105
106 badframe:
107 force_sig(SIGSEGV, current);
108 return 0;
109 }
110
sys_rt_sigreturn(void)111 asmlinkage int sys_rt_sigreturn(void)
112 {
113 struct rt_sigframe __user *frame = (struct rt_sigframe __user *) __frame->sp;
114 sigset_t set;
115 int gr8;
116
117 if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
118 goto badframe;
119 if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
120 goto badframe;
121
122 set_current_blocked(&set);
123
124 if (restore_sigcontext(&frame->uc.uc_mcontext, &gr8))
125 goto badframe;
126
127 if (restore_altstack(&frame->uc.uc_stack))
128 goto badframe;
129
130 return gr8;
131
132 badframe:
133 force_sig(SIGSEGV, current);
134 return 0;
135 }
136
137 /*
138 * Set up a signal frame
139 */
setup_sigcontext(struct sigcontext __user * sc,unsigned long mask)140 static int setup_sigcontext(struct sigcontext __user *sc, unsigned long mask)
141 {
142 save_user_regs(current->thread.user);
143
144 if (copy_to_user(&sc->sc_context, current->thread.user, sizeof(sc->sc_context)) != 0)
145 goto badframe;
146
147 /* non-iBCS2 extensions.. */
148 if (__put_user(mask, &sc->sc_oldmask) < 0)
149 goto badframe;
150
151 return 0;
152
153 badframe:
154 return 1;
155 }
156
157 /*****************************************************************************/
158 /*
159 * Determine which stack to use..
160 */
get_sigframe(struct ksignal * ksig,size_t frame_size)161 static inline void __user *get_sigframe(struct ksignal *ksig,
162 size_t frame_size)
163 {
164 unsigned long sp = sigsp(__frame->sp, ksig);
165
166 return (void __user *) ((sp - frame_size) & ~7UL);
167
168 } /* end get_sigframe() */
169
170 /*****************************************************************************/
171 /*
172 *
173 */
setup_frame(struct ksignal * ksig,sigset_t * set)174 static int setup_frame(struct ksignal *ksig, sigset_t *set)
175 {
176 struct sigframe __user *frame;
177 int rsig, sig = ksig->sig;
178
179 set_fs(USER_DS);
180
181 frame = get_sigframe(ksig, sizeof(*frame));
182
183 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
184 return -EFAULT;
185
186 rsig = sig;
187 if (sig < 32 &&
188 __current_thread_info->exec_domain &&
189 __current_thread_info->exec_domain->signal_invmap)
190 rsig = __current_thread_info->exec_domain->signal_invmap[sig];
191
192 if (__put_user(rsig, &frame->sig) < 0)
193 return -EFAULT;
194
195 if (setup_sigcontext(&frame->sc, set->sig[0]))
196 return -EFAULT;
197
198 if (_NSIG_WORDS > 1) {
199 if (__copy_to_user(frame->extramask, &set->sig[1],
200 sizeof(frame->extramask)))
201 return -EFAULT;
202 }
203
204 /* Set up to return from userspace. If provided, use a stub
205 * already in userspace. */
206 if (ksig->ka.sa.sa_flags & SA_RESTORER) {
207 if (__put_user(ksig->ka.sa.sa_restorer, &frame->pretcode) < 0)
208 return -EFAULT;
209 }
210 else {
211 /* Set up the following code on the stack:
212 * setlos #__NR_sigreturn,gr7
213 * tira gr0,0
214 */
215 if (__put_user((__sigrestore_t)frame->retcode, &frame->pretcode) ||
216 __put_user(0x8efc0000|__NR_sigreturn, &frame->retcode[0]) ||
217 __put_user(0xc0700000, &frame->retcode[1]))
218 return -EFAULT;
219
220 flush_icache_range((unsigned long) frame->retcode,
221 (unsigned long) (frame->retcode + 2));
222 }
223
224 /* Set up registers for the signal handler */
225 if (current->personality & FDPIC_FUNCPTRS) {
226 struct fdpic_func_descriptor __user *funcptr =
227 (struct fdpic_func_descriptor __user *) ksig->ka.sa.sa_handler;
228 struct fdpic_func_descriptor desc;
229 if (copy_from_user(&desc, funcptr, sizeof(desc)))
230 return -EFAULT;
231 __frame->pc = desc.text;
232 __frame->gr15 = desc.GOT;
233 } else {
234 __frame->pc = (unsigned long) ksig->ka.sa.sa_handler;
235 __frame->gr15 = 0;
236 }
237
238 __frame->sp = (unsigned long) frame;
239 __frame->lr = (unsigned long) &frame->retcode;
240 __frame->gr8 = sig;
241
242 #if DEBUG_SIG
243 printk("SIG deliver %d (%s:%d): sp=%p pc=%lx ra=%p\n",
244 sig, current->comm, current->pid, frame, __frame->pc,
245 frame->pretcode);
246 #endif
247
248 return 0;
249 } /* end setup_frame() */
250
251 /*****************************************************************************/
252 /*
253 *
254 */
setup_rt_frame(struct ksignal * ksig,sigset_t * set)255 static int setup_rt_frame(struct ksignal *ksig, sigset_t *set)
256 {
257 struct rt_sigframe __user *frame;
258 int rsig, sig = ksig->sig;
259
260 set_fs(USER_DS);
261
262 frame = get_sigframe(ksig, sizeof(*frame));
263
264 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
265 return -EFAULT;
266
267 rsig = sig;
268 if (sig < 32 &&
269 __current_thread_info->exec_domain &&
270 __current_thread_info->exec_domain->signal_invmap)
271 rsig = __current_thread_info->exec_domain->signal_invmap[sig];
272
273 if (__put_user(rsig, &frame->sig) ||
274 __put_user(&frame->info, &frame->pinfo) ||
275 __put_user(&frame->uc, &frame->puc))
276 return -EFAULT;
277
278 if (copy_siginfo_to_user(&frame->info, &ksig->info))
279 return -EFAULT;
280
281 /* Create the ucontext. */
282 if (__put_user(0, &frame->uc.uc_flags) ||
283 __put_user(NULL, &frame->uc.uc_link) ||
284 __save_altstack(&frame->uc.uc_stack, __frame->sp))
285 return -EFAULT;
286
287 if (setup_sigcontext(&frame->uc.uc_mcontext, set->sig[0]))
288 return -EFAULT;
289
290 if (__copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)))
291 return -EFAULT;
292
293 /* Set up to return from userspace. If provided, use a stub
294 * already in userspace. */
295 if (ksig->ka.sa.sa_flags & SA_RESTORER) {
296 if (__put_user(ksig->ka.sa.sa_restorer, &frame->pretcode))
297 return -EFAULT;
298 }
299 else {
300 /* Set up the following code on the stack:
301 * setlos #__NR_sigreturn,gr7
302 * tira gr0,0
303 */
304 if (__put_user((__sigrestore_t)frame->retcode, &frame->pretcode) ||
305 __put_user(0x8efc0000|__NR_rt_sigreturn, &frame->retcode[0]) ||
306 __put_user(0xc0700000, &frame->retcode[1]))
307 return -EFAULT;
308
309 flush_icache_range((unsigned long) frame->retcode,
310 (unsigned long) (frame->retcode + 2));
311 }
312
313 /* Set up registers for signal handler */
314 if (current->personality & FDPIC_FUNCPTRS) {
315 struct fdpic_func_descriptor __user *funcptr =
316 (struct fdpic_func_descriptor __user *) ksig->ka.sa.sa_handler;
317 struct fdpic_func_descriptor desc;
318 if (copy_from_user(&desc, funcptr, sizeof(desc)))
319 return -EFAULT;
320 __frame->pc = desc.text;
321 __frame->gr15 = desc.GOT;
322 } else {
323 __frame->pc = (unsigned long) ksig->ka.sa.sa_handler;
324 __frame->gr15 = 0;
325 }
326
327 __frame->sp = (unsigned long) frame;
328 __frame->lr = (unsigned long) &frame->retcode;
329 __frame->gr8 = sig;
330 __frame->gr9 = (unsigned long) &frame->info;
331
332 #if DEBUG_SIG
333 printk("SIG deliver %d (%s:%d): sp=%p pc=%lx ra=%p\n",
334 sig, current->comm, current->pid, frame, __frame->pc,
335 frame->pretcode);
336 #endif
337 return 0;
338
339 } /* end setup_rt_frame() */
340
341 /*****************************************************************************/
342 /*
343 * OK, we're invoking a handler
344 */
handle_signal(struct ksignal * ksig)345 static void handle_signal(struct ksignal *ksig)
346 {
347 sigset_t *oldset = sigmask_to_save();
348 int ret;
349
350 /* Are we from a system call? */
351 if (__frame->syscallno != -1) {
352 /* If so, check system call restarting.. */
353 switch (__frame->gr8) {
354 case -ERESTART_RESTARTBLOCK:
355 case -ERESTARTNOHAND:
356 __frame->gr8 = -EINTR;
357 break;
358
359 case -ERESTARTSYS:
360 if (!(ksig->ka.sa.sa_flags & SA_RESTART)) {
361 __frame->gr8 = -EINTR;
362 break;
363 }
364
365 /* fallthrough */
366 case -ERESTARTNOINTR:
367 __frame->gr8 = __frame->orig_gr8;
368 __frame->pc -= 4;
369 }
370 __frame->syscallno = -1;
371 }
372
373 /* Set up the stack frame */
374 if (ksig->ka.sa.sa_flags & SA_SIGINFO)
375 ret = setup_rt_frame(ksig, oldset);
376 else
377 ret = setup_frame(ksig, oldset);
378
379 signal_setup_done(ret, ksig, test_thread_flag(TIF_SINGLESTEP));
380 } /* end handle_signal() */
381
382 /*****************************************************************************/
383 /*
384 * Note that 'init' is a special process: it doesn't get signals it doesn't
385 * want to handle. Thus you cannot kill init even with a SIGKILL even by
386 * mistake.
387 */
do_signal(void)388 static void do_signal(void)
389 {
390 struct ksignal ksig;
391
392 if (get_signal(&ksig)) {
393 handle_signal(&ksig);
394 return;
395 }
396
397 /* Did we come from a system call? */
398 if (__frame->syscallno != -1) {
399 /* Restart the system call - no handlers present */
400 switch (__frame->gr8) {
401 case -ERESTARTNOHAND:
402 case -ERESTARTSYS:
403 case -ERESTARTNOINTR:
404 __frame->gr8 = __frame->orig_gr8;
405 __frame->pc -= 4;
406 break;
407
408 case -ERESTART_RESTARTBLOCK:
409 __frame->gr7 = __NR_restart_syscall;
410 __frame->pc -= 4;
411 break;
412 }
413 __frame->syscallno = -1;
414 }
415
416 /* if there's no signal to deliver, we just put the saved sigmask
417 * back */
418 restore_saved_sigmask();
419 } /* end do_signal() */
420
421 /*****************************************************************************/
422 /*
423 * notification of userspace execution resumption
424 * - triggered by the TIF_WORK_MASK flags
425 */
do_notify_resume(__u32 thread_info_flags)426 asmlinkage void do_notify_resume(__u32 thread_info_flags)
427 {
428 /* pending single-step? */
429 if (thread_info_flags & _TIF_SINGLESTEP)
430 clear_thread_flag(TIF_SINGLESTEP);
431
432 /* deal with pending signal delivery */
433 if (thread_info_flags & _TIF_SIGPENDING)
434 do_signal();
435
436 /* deal with notification on about to resume userspace execution */
437 if (thread_info_flags & _TIF_NOTIFY_RESUME) {
438 clear_thread_flag(TIF_NOTIFY_RESUME);
439 tracehook_notify_resume(__frame);
440 }
441
442 } /* end do_notify_resume() */
443