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 sig = ksig->sig;
178
179 frame = get_sigframe(ksig, sizeof(*frame));
180
181 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
182 return -EFAULT;
183
184 if (__put_user(sig, &frame->sig) < 0)
185 return -EFAULT;
186
187 if (setup_sigcontext(&frame->sc, set->sig[0]))
188 return -EFAULT;
189
190 if (_NSIG_WORDS > 1) {
191 if (__copy_to_user(frame->extramask, &set->sig[1],
192 sizeof(frame->extramask)))
193 return -EFAULT;
194 }
195
196 /* Set up to return from userspace. If provided, use a stub
197 * already in userspace. */
198 if (ksig->ka.sa.sa_flags & SA_RESTORER) {
199 if (__put_user(ksig->ka.sa.sa_restorer, &frame->pretcode) < 0)
200 return -EFAULT;
201 }
202 else {
203 /* Set up the following code on the stack:
204 * setlos #__NR_sigreturn,gr7
205 * tira gr0,0
206 */
207 if (__put_user((__sigrestore_t)frame->retcode, &frame->pretcode) ||
208 __put_user(0x8efc0000|__NR_sigreturn, &frame->retcode[0]) ||
209 __put_user(0xc0700000, &frame->retcode[1]))
210 return -EFAULT;
211
212 flush_icache_range((unsigned long) frame->retcode,
213 (unsigned long) (frame->retcode + 2));
214 }
215
216 /* Set up registers for the signal handler */
217 if (current->personality & FDPIC_FUNCPTRS) {
218 struct fdpic_func_descriptor __user *funcptr =
219 (struct fdpic_func_descriptor __user *) ksig->ka.sa.sa_handler;
220 struct fdpic_func_descriptor desc;
221 if (copy_from_user(&desc, funcptr, sizeof(desc)))
222 return -EFAULT;
223 __frame->pc = desc.text;
224 __frame->gr15 = desc.GOT;
225 } else {
226 __frame->pc = (unsigned long) ksig->ka.sa.sa_handler;
227 __frame->gr15 = 0;
228 }
229
230 __frame->sp = (unsigned long) frame;
231 __frame->lr = (unsigned long) &frame->retcode;
232 __frame->gr8 = sig;
233
234 #if DEBUG_SIG
235 printk("SIG deliver %d (%s:%d): sp=%p pc=%lx ra=%p\n",
236 sig, current->comm, current->pid, frame, __frame->pc,
237 frame->pretcode);
238 #endif
239
240 return 0;
241 } /* end setup_frame() */
242
243 /*****************************************************************************/
244 /*
245 *
246 */
setup_rt_frame(struct ksignal * ksig,sigset_t * set)247 static int setup_rt_frame(struct ksignal *ksig, sigset_t *set)
248 {
249 struct rt_sigframe __user *frame;
250 int sig = ksig->sig;
251
252 frame = get_sigframe(ksig, sizeof(*frame));
253
254 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
255 return -EFAULT;
256
257 if (__put_user(sig, &frame->sig) ||
258 __put_user(&frame->info, &frame->pinfo) ||
259 __put_user(&frame->uc, &frame->puc))
260 return -EFAULT;
261
262 if (copy_siginfo_to_user(&frame->info, &ksig->info))
263 return -EFAULT;
264
265 /* Create the ucontext. */
266 if (__put_user(0, &frame->uc.uc_flags) ||
267 __put_user(NULL, &frame->uc.uc_link) ||
268 __save_altstack(&frame->uc.uc_stack, __frame->sp))
269 return -EFAULT;
270
271 if (setup_sigcontext(&frame->uc.uc_mcontext, set->sig[0]))
272 return -EFAULT;
273
274 if (__copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)))
275 return -EFAULT;
276
277 /* Set up to return from userspace. If provided, use a stub
278 * already in userspace. */
279 if (ksig->ka.sa.sa_flags & SA_RESTORER) {
280 if (__put_user(ksig->ka.sa.sa_restorer, &frame->pretcode))
281 return -EFAULT;
282 }
283 else {
284 /* Set up the following code on the stack:
285 * setlos #__NR_sigreturn,gr7
286 * tira gr0,0
287 */
288 if (__put_user((__sigrestore_t)frame->retcode, &frame->pretcode) ||
289 __put_user(0x8efc0000|__NR_rt_sigreturn, &frame->retcode[0]) ||
290 __put_user(0xc0700000, &frame->retcode[1]))
291 return -EFAULT;
292
293 flush_icache_range((unsigned long) frame->retcode,
294 (unsigned long) (frame->retcode + 2));
295 }
296
297 /* Set up registers for signal handler */
298 if (current->personality & FDPIC_FUNCPTRS) {
299 struct fdpic_func_descriptor __user *funcptr =
300 (struct fdpic_func_descriptor __user *) ksig->ka.sa.sa_handler;
301 struct fdpic_func_descriptor desc;
302 if (copy_from_user(&desc, funcptr, sizeof(desc)))
303 return -EFAULT;
304 __frame->pc = desc.text;
305 __frame->gr15 = desc.GOT;
306 } else {
307 __frame->pc = (unsigned long) ksig->ka.sa.sa_handler;
308 __frame->gr15 = 0;
309 }
310
311 __frame->sp = (unsigned long) frame;
312 __frame->lr = (unsigned long) &frame->retcode;
313 __frame->gr8 = sig;
314 __frame->gr9 = (unsigned long) &frame->info;
315
316 #if DEBUG_SIG
317 printk("SIG deliver %d (%s:%d): sp=%p pc=%lx ra=%p\n",
318 sig, current->comm, current->pid, frame, __frame->pc,
319 frame->pretcode);
320 #endif
321 return 0;
322
323 } /* end setup_rt_frame() */
324
325 /*****************************************************************************/
326 /*
327 * OK, we're invoking a handler
328 */
handle_signal(struct ksignal * ksig)329 static void handle_signal(struct ksignal *ksig)
330 {
331 sigset_t *oldset = sigmask_to_save();
332 int ret;
333
334 /* Are we from a system call? */
335 if (__frame->syscallno != -1) {
336 /* If so, check system call restarting.. */
337 switch (__frame->gr8) {
338 case -ERESTART_RESTARTBLOCK:
339 case -ERESTARTNOHAND:
340 __frame->gr8 = -EINTR;
341 break;
342
343 case -ERESTARTSYS:
344 if (!(ksig->ka.sa.sa_flags & SA_RESTART)) {
345 __frame->gr8 = -EINTR;
346 break;
347 }
348
349 /* fallthrough */
350 case -ERESTARTNOINTR:
351 __frame->gr8 = __frame->orig_gr8;
352 __frame->pc -= 4;
353 }
354 __frame->syscallno = -1;
355 }
356
357 /* Set up the stack frame */
358 if (ksig->ka.sa.sa_flags & SA_SIGINFO)
359 ret = setup_rt_frame(ksig, oldset);
360 else
361 ret = setup_frame(ksig, oldset);
362
363 signal_setup_done(ret, ksig, test_thread_flag(TIF_SINGLESTEP));
364 } /* end handle_signal() */
365
366 /*****************************************************************************/
367 /*
368 * Note that 'init' is a special process: it doesn't get signals it doesn't
369 * want to handle. Thus you cannot kill init even with a SIGKILL even by
370 * mistake.
371 */
do_signal(void)372 static void do_signal(void)
373 {
374 struct ksignal ksig;
375
376 if (get_signal(&ksig)) {
377 handle_signal(&ksig);
378 return;
379 }
380
381 /* Did we come from a system call? */
382 if (__frame->syscallno != -1) {
383 /* Restart the system call - no handlers present */
384 switch (__frame->gr8) {
385 case -ERESTARTNOHAND:
386 case -ERESTARTSYS:
387 case -ERESTARTNOINTR:
388 __frame->gr8 = __frame->orig_gr8;
389 __frame->pc -= 4;
390 break;
391
392 case -ERESTART_RESTARTBLOCK:
393 __frame->gr7 = __NR_restart_syscall;
394 __frame->pc -= 4;
395 break;
396 }
397 __frame->syscallno = -1;
398 }
399
400 /* if there's no signal to deliver, we just put the saved sigmask
401 * back */
402 restore_saved_sigmask();
403 } /* end do_signal() */
404
405 /*****************************************************************************/
406 /*
407 * notification of userspace execution resumption
408 * - triggered by the TIF_WORK_MASK flags
409 */
do_notify_resume(__u32 thread_info_flags)410 asmlinkage void do_notify_resume(__u32 thread_info_flags)
411 {
412 /* pending single-step? */
413 if (thread_info_flags & _TIF_SINGLESTEP)
414 clear_thread_flag(TIF_SINGLESTEP);
415
416 /* deal with pending signal delivery */
417 if (thread_info_flags & _TIF_SIGPENDING)
418 do_signal();
419
420 /* deal with notification on about to resume userspace execution */
421 if (thread_info_flags & _TIF_NOTIFY_RESUME) {
422 clear_thread_flag(TIF_NOTIFY_RESUME);
423 tracehook_notify_resume(__frame);
424 }
425
426 } /* end do_notify_resume() */
427