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