1 /*
2 * arch/sh/kernel/signal_64.c
3 *
4 * Copyright (C) 2000, 2001 Paolo Alberelli
5 * Copyright (C) 2003 - 2008 Paul Mundt
6 * Copyright (C) 2004 Richard Curnow
7 *
8 * This file is subject to the terms and conditions of the GNU General Public
9 * License. See the file "COPYING" in the main directory of this archive
10 * for more details.
11 */
12 #include <linux/rwsem.h>
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/personality.h>
21 #include <linux/ptrace.h>
22 #include <linux/unistd.h>
23 #include <linux/stddef.h>
24 #include <linux/tracehook.h>
25 #include <asm/ucontext.h>
26 #include <asm/uaccess.h>
27 #include <asm/pgtable.h>
28 #include <asm/cacheflush.h>
29 #include <asm/fpu.h>
30
31 #define REG_RET 9
32 #define REG_ARG1 2
33 #define REG_ARG2 3
34 #define REG_ARG3 4
35 #define REG_SP 15
36 #define REG_PR 18
37 #define REF_REG_RET regs->regs[REG_RET]
38 #define REF_REG_SP regs->regs[REG_SP]
39 #define DEREF_REG_PR regs->regs[REG_PR]
40
41 #define DEBUG_SIG 0
42
43 static void
44 handle_signal(struct ksignal *ksig, struct pt_regs *regs);
45
46 static inline void
handle_syscall_restart(struct pt_regs * regs,struct sigaction * sa)47 handle_syscall_restart(struct pt_regs *regs, struct sigaction *sa)
48 {
49 /* If we're not from a syscall, bail out */
50 if (regs->syscall_nr < 0)
51 return;
52
53 /* check for system call restart.. */
54 switch (regs->regs[REG_RET]) {
55 case -ERESTART_RESTARTBLOCK:
56 case -ERESTARTNOHAND:
57 no_system_call_restart:
58 regs->regs[REG_RET] = -EINTR;
59 break;
60
61 case -ERESTARTSYS:
62 if (!(sa->sa_flags & SA_RESTART))
63 goto no_system_call_restart;
64 /* fallthrough */
65 case -ERESTARTNOINTR:
66 /* Decode syscall # */
67 regs->regs[REG_RET] = regs->syscall_nr;
68 regs->pc -= 4;
69 break;
70 }
71 }
72
73 /*
74 * Note that 'init' is a special process: it doesn't get signals it doesn't
75 * want to handle. Thus you cannot kill init even with a SIGKILL even by
76 * mistake.
77 *
78 * Note that we go through the signals twice: once to check the signals that
79 * the kernel can handle, and then we build all the user-level signal handling
80 * stack-frames in one go after that.
81 */
do_signal(struct pt_regs * regs)82 static void do_signal(struct pt_regs *regs)
83 {
84 struct ksignal ksig;
85
86 /*
87 * We want the common case to go fast, which
88 * is why we may in certain cases get here from
89 * kernel mode. Just return without doing anything
90 * if so.
91 */
92 if (!user_mode(regs))
93 return;
94
95 if (get_signal(&ksig)) {
96 handle_syscall_restart(regs, &ksig.ka.sa);
97
98 /* Whee! Actually deliver the signal. */
99 handle_signal(&ksig, regs);
100 return;
101 }
102
103 /* Did we come from a system call? */
104 if (regs->syscall_nr >= 0) {
105 /* Restart the system call - no handlers present */
106 switch (regs->regs[REG_RET]) {
107 case -ERESTARTNOHAND:
108 case -ERESTARTSYS:
109 case -ERESTARTNOINTR:
110 /* Decode Syscall # */
111 regs->regs[REG_RET] = regs->syscall_nr;
112 regs->pc -= 4;
113 break;
114
115 case -ERESTART_RESTARTBLOCK:
116 regs->regs[REG_RET] = __NR_restart_syscall;
117 regs->pc -= 4;
118 break;
119 }
120 }
121
122 /* No signal to deliver -- put the saved sigmask back */
123 restore_saved_sigmask();
124 }
125
126 /*
127 * Do a signal return; undo the signal stack.
128 */
129 struct sigframe {
130 struct sigcontext sc;
131 unsigned long extramask[_NSIG_WORDS-1];
132 long long retcode[2];
133 };
134
135 struct rt_sigframe {
136 struct siginfo __user *pinfo;
137 void *puc;
138 struct siginfo info;
139 struct ucontext uc;
140 long long retcode[2];
141 };
142
143 #ifdef CONFIG_SH_FPU
144 static inline int
restore_sigcontext_fpu(struct pt_regs * regs,struct sigcontext __user * sc)145 restore_sigcontext_fpu(struct pt_regs *regs, struct sigcontext __user *sc)
146 {
147 int err = 0;
148 int fpvalid;
149
150 err |= __get_user (fpvalid, &sc->sc_fpvalid);
151 conditional_used_math(fpvalid);
152 if (! fpvalid)
153 return err;
154
155 if (current == last_task_used_math) {
156 last_task_used_math = NULL;
157 regs->sr |= SR_FD;
158 }
159
160 err |= __copy_from_user(¤t->thread.xstate->hardfpu, &sc->sc_fpregs[0],
161 (sizeof(long long) * 32) + (sizeof(int) * 1));
162
163 return err;
164 }
165
166 static inline int
setup_sigcontext_fpu(struct pt_regs * regs,struct sigcontext __user * sc)167 setup_sigcontext_fpu(struct pt_regs *regs, struct sigcontext __user *sc)
168 {
169 int err = 0;
170 int fpvalid;
171
172 fpvalid = !!used_math();
173 err |= __put_user(fpvalid, &sc->sc_fpvalid);
174 if (! fpvalid)
175 return err;
176
177 if (current == last_task_used_math) {
178 enable_fpu();
179 save_fpu(current);
180 disable_fpu();
181 last_task_used_math = NULL;
182 regs->sr |= SR_FD;
183 }
184
185 err |= __copy_to_user(&sc->sc_fpregs[0], ¤t->thread.xstate->hardfpu,
186 (sizeof(long long) * 32) + (sizeof(int) * 1));
187 clear_used_math();
188
189 return err;
190 }
191 #else
192 static inline int
restore_sigcontext_fpu(struct pt_regs * regs,struct sigcontext __user * sc)193 restore_sigcontext_fpu(struct pt_regs *regs, struct sigcontext __user *sc)
194 {
195 return 0;
196 }
197 static inline int
setup_sigcontext_fpu(struct pt_regs * regs,struct sigcontext __user * sc)198 setup_sigcontext_fpu(struct pt_regs *regs, struct sigcontext __user *sc)
199 {
200 return 0;
201 }
202 #endif
203
204 static int
restore_sigcontext(struct pt_regs * regs,struct sigcontext __user * sc,long long * r2_p)205 restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc, long long *r2_p)
206 {
207 unsigned int err = 0;
208 unsigned long long current_sr, new_sr;
209 #define SR_MASK 0xffff8cfd
210
211 #define COPY(x) err |= __get_user(regs->x, &sc->sc_##x)
212
213 COPY(regs[0]); COPY(regs[1]); COPY(regs[2]); COPY(regs[3]);
214 COPY(regs[4]); COPY(regs[5]); COPY(regs[6]); COPY(regs[7]);
215 COPY(regs[8]); COPY(regs[9]); COPY(regs[10]); COPY(regs[11]);
216 COPY(regs[12]); COPY(regs[13]); COPY(regs[14]); COPY(regs[15]);
217 COPY(regs[16]); COPY(regs[17]); COPY(regs[18]); COPY(regs[19]);
218 COPY(regs[20]); COPY(regs[21]); COPY(regs[22]); COPY(regs[23]);
219 COPY(regs[24]); COPY(regs[25]); COPY(regs[26]); COPY(regs[27]);
220 COPY(regs[28]); COPY(regs[29]); COPY(regs[30]); COPY(regs[31]);
221 COPY(regs[32]); COPY(regs[33]); COPY(regs[34]); COPY(regs[35]);
222 COPY(regs[36]); COPY(regs[37]); COPY(regs[38]); COPY(regs[39]);
223 COPY(regs[40]); COPY(regs[41]); COPY(regs[42]); COPY(regs[43]);
224 COPY(regs[44]); COPY(regs[45]); COPY(regs[46]); COPY(regs[47]);
225 COPY(regs[48]); COPY(regs[49]); COPY(regs[50]); COPY(regs[51]);
226 COPY(regs[52]); COPY(regs[53]); COPY(regs[54]); COPY(regs[55]);
227 COPY(regs[56]); COPY(regs[57]); COPY(regs[58]); COPY(regs[59]);
228 COPY(regs[60]); COPY(regs[61]); COPY(regs[62]);
229 COPY(tregs[0]); COPY(tregs[1]); COPY(tregs[2]); COPY(tregs[3]);
230 COPY(tregs[4]); COPY(tregs[5]); COPY(tregs[6]); COPY(tregs[7]);
231
232 /* Prevent the signal handler manipulating SR in a way that can
233 crash the kernel. i.e. only allow S, Q, M, PR, SZ, FR to be
234 modified */
235 current_sr = regs->sr;
236 err |= __get_user(new_sr, &sc->sc_sr);
237 regs->sr &= SR_MASK;
238 regs->sr |= (new_sr & ~SR_MASK);
239
240 COPY(pc);
241
242 #undef COPY
243
244 /* Must do this last in case it sets regs->sr.fd (i.e. after rest of sr
245 * has been restored above.) */
246 err |= restore_sigcontext_fpu(regs, sc);
247
248 regs->syscall_nr = -1; /* disable syscall checks */
249 err |= __get_user(*r2_p, &sc->sc_regs[REG_RET]);
250 return err;
251 }
252
sys_sigreturn(unsigned long r2,unsigned long r3,unsigned long r4,unsigned long r5,unsigned long r6,unsigned long r7,struct pt_regs * regs)253 asmlinkage int sys_sigreturn(unsigned long r2, unsigned long r3,
254 unsigned long r4, unsigned long r5,
255 unsigned long r6, unsigned long r7,
256 struct pt_regs * regs)
257 {
258 struct sigframe __user *frame = (struct sigframe __user *) (long) REF_REG_SP;
259 sigset_t set;
260 long long ret;
261
262 /* Always make any pending restarted system calls return -EINTR */
263 current->restart_block.fn = do_no_restart_syscall;
264
265 if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
266 goto badframe;
267
268 if (__get_user(set.sig[0], &frame->sc.oldmask)
269 || (_NSIG_WORDS > 1
270 && __copy_from_user(&set.sig[1], &frame->extramask,
271 sizeof(frame->extramask))))
272 goto badframe;
273
274 set_current_blocked(&set);
275
276 if (restore_sigcontext(regs, &frame->sc, &ret))
277 goto badframe;
278 regs->pc -= 4;
279
280 return (int) ret;
281
282 badframe:
283 force_sig(SIGSEGV, current);
284 return 0;
285 }
286
sys_rt_sigreturn(unsigned long r2,unsigned long r3,unsigned long r4,unsigned long r5,unsigned long r6,unsigned long r7,struct pt_regs * regs)287 asmlinkage int sys_rt_sigreturn(unsigned long r2, unsigned long r3,
288 unsigned long r4, unsigned long r5,
289 unsigned long r6, unsigned long r7,
290 struct pt_regs * regs)
291 {
292 struct rt_sigframe __user *frame = (struct rt_sigframe __user *) (long) REF_REG_SP;
293 sigset_t set;
294 long long ret;
295
296 /* Always make any pending restarted system calls return -EINTR */
297 current->restart_block.fn = do_no_restart_syscall;
298
299 if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
300 goto badframe;
301
302 if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
303 goto badframe;
304
305 set_current_blocked(&set);
306
307 if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &ret))
308 goto badframe;
309 regs->pc -= 4;
310
311 if (restore_altstack(&frame->uc.uc_stack))
312 goto badframe;
313
314 return (int) ret;
315
316 badframe:
317 force_sig(SIGSEGV, current);
318 return 0;
319 }
320
321 /*
322 * Set up a signal frame.
323 */
324 static int
setup_sigcontext(struct sigcontext __user * sc,struct pt_regs * regs,unsigned long mask)325 setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs,
326 unsigned long mask)
327 {
328 int err = 0;
329
330 /* Do this first, otherwise is this sets sr->fd, that value isn't preserved. */
331 err |= setup_sigcontext_fpu(regs, sc);
332
333 #define COPY(x) err |= __put_user(regs->x, &sc->sc_##x)
334
335 COPY(regs[0]); COPY(regs[1]); COPY(regs[2]); COPY(regs[3]);
336 COPY(regs[4]); COPY(regs[5]); COPY(regs[6]); COPY(regs[7]);
337 COPY(regs[8]); COPY(regs[9]); COPY(regs[10]); COPY(regs[11]);
338 COPY(regs[12]); COPY(regs[13]); COPY(regs[14]); COPY(regs[15]);
339 COPY(regs[16]); COPY(regs[17]); COPY(regs[18]); COPY(regs[19]);
340 COPY(regs[20]); COPY(regs[21]); COPY(regs[22]); COPY(regs[23]);
341 COPY(regs[24]); COPY(regs[25]); COPY(regs[26]); COPY(regs[27]);
342 COPY(regs[28]); COPY(regs[29]); COPY(regs[30]); COPY(regs[31]);
343 COPY(regs[32]); COPY(regs[33]); COPY(regs[34]); COPY(regs[35]);
344 COPY(regs[36]); COPY(regs[37]); COPY(regs[38]); COPY(regs[39]);
345 COPY(regs[40]); COPY(regs[41]); COPY(regs[42]); COPY(regs[43]);
346 COPY(regs[44]); COPY(regs[45]); COPY(regs[46]); COPY(regs[47]);
347 COPY(regs[48]); COPY(regs[49]); COPY(regs[50]); COPY(regs[51]);
348 COPY(regs[52]); COPY(regs[53]); COPY(regs[54]); COPY(regs[55]);
349 COPY(regs[56]); COPY(regs[57]); COPY(regs[58]); COPY(regs[59]);
350 COPY(regs[60]); COPY(regs[61]); COPY(regs[62]);
351 COPY(tregs[0]); COPY(tregs[1]); COPY(tregs[2]); COPY(tregs[3]);
352 COPY(tregs[4]); COPY(tregs[5]); COPY(tregs[6]); COPY(tregs[7]);
353 COPY(sr); COPY(pc);
354
355 #undef COPY
356
357 err |= __put_user(mask, &sc->oldmask);
358
359 return err;
360 }
361
362 /*
363 * Determine which stack to use..
364 */
365 static inline void __user *
get_sigframe(struct k_sigaction * ka,unsigned long sp,size_t frame_size)366 get_sigframe(struct k_sigaction *ka, unsigned long sp, size_t frame_size)
367 {
368 if ((ka->sa.sa_flags & SA_ONSTACK) != 0 && ! sas_ss_flags(sp))
369 sp = current->sas_ss_sp + current->sas_ss_size;
370
371 return (void __user *)((sp - frame_size) & -8ul);
372 }
373
374 void sa_default_restorer(void); /* See comments below */
375 void sa_default_rt_restorer(void); /* See comments below */
376
setup_frame(struct ksignal * ksig,sigset_t * set,struct pt_regs * regs)377 static int setup_frame(struct ksignal *ksig, sigset_t *set, struct pt_regs *regs)
378 {
379 struct sigframe __user *frame;
380 int err = 0, sig = ksig->sig;
381 int signal;
382
383 frame = get_sigframe(&ksig->ka, regs->regs[REG_SP], sizeof(*frame));
384
385 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
386 return -EFAULT;
387
388 err |= setup_sigcontext(&frame->sc, regs, set->sig[0]);
389
390 /* Give up earlier as i386, in case */
391 if (err)
392 return -EFAULT;
393
394 if (_NSIG_WORDS > 1) {
395 err |= __copy_to_user(frame->extramask, &set->sig[1],
396 sizeof(frame->extramask)); }
397
398 /* Give up earlier as i386, in case */
399 if (err)
400 return -EFAULT;
401
402 /* Set up to return from userspace. If provided, use a stub
403 already in userspace. */
404 if (ksig->ka.sa.sa_flags & SA_RESTORER) {
405 /*
406 * On SH5 all edited pointers are subject to NEFF
407 */
408 DEREF_REG_PR = neff_sign_extend((unsigned long)
409 ksig->ka->sa.sa_restorer | 0x1);
410 } else {
411 /*
412 * Different approach on SH5.
413 * . Endianness independent asm code gets placed in entry.S .
414 * This is limited to four ASM instructions corresponding
415 * to two long longs in size.
416 * . err checking is done on the else branch only
417 * . flush_icache_range() is called upon __put_user() only
418 * . all edited pointers are subject to NEFF
419 * . being code, linker turns ShMedia bit on, always
420 * dereference index -1.
421 */
422 DEREF_REG_PR = neff_sign_extend((unsigned long)
423 frame->retcode | 0x01);
424
425 if (__copy_to_user(frame->retcode,
426 (void *)((unsigned long)sa_default_restorer & (~1)), 16) != 0)
427 return -EFAULT;
428
429 /* Cohere the trampoline with the I-cache. */
430 flush_cache_sigtramp(DEREF_REG_PR-1);
431 }
432
433 /*
434 * Set up registers for signal handler.
435 * All edited pointers are subject to NEFF.
436 */
437 regs->regs[REG_SP] = neff_sign_extend((unsigned long)frame);
438 regs->regs[REG_ARG1] = sig; /* Arg for signal handler */
439
440 /* FIXME:
441 The glibc profiling support for SH-5 needs to be passed a sigcontext
442 so it can retrieve the PC. At some point during 2003 the glibc
443 support was changed to receive the sigcontext through the 2nd
444 argument, but there are still versions of libc.so in use that use
445 the 3rd argument. Until libc.so is stabilised, pass the sigcontext
446 through both 2nd and 3rd arguments.
447 */
448
449 regs->regs[REG_ARG2] = (unsigned long long)(unsigned long)(signed long)&frame->sc;
450 regs->regs[REG_ARG3] = (unsigned long long)(unsigned long)(signed long)&frame->sc;
451
452 regs->pc = neff_sign_extend((unsigned long)ksig->ka.sa.sa_handler);
453
454 /* Broken %016Lx */
455 pr_debug("SIG deliver (#%d,%s:%d): sp=%p pc=%08Lx%08Lx link=%08Lx%08Lx\n",
456 sig, current->comm, current->pid, frame,
457 regs->pc >> 32, regs->pc & 0xffffffff,
458 DEREF_REG_PR >> 32, DEREF_REG_PR & 0xffffffff);
459
460 return 0;
461 }
462
setup_rt_frame(struct ksignal * kig,sigset_t * set,struct pt_regs * regs)463 static int setup_rt_frame(struct ksignal *kig, sigset_t *set,
464 struct pt_regs *regs)
465 {
466 struct rt_sigframe __user *frame;
467 int err = 0, sig = ksig->sig;
468
469 frame = get_sigframe(&ksig->ka, regs->regs[REG_SP], sizeof(*frame));
470
471 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
472 return -EFAULT;
473
474 err |= __put_user(&frame->info, &frame->pinfo);
475 err |= __put_user(&frame->uc, &frame->puc);
476 err |= copy_siginfo_to_user(&frame->info, &ksig->info);
477
478 /* Give up earlier as i386, in case */
479 if (err)
480 return -EFAULT;
481
482 /* Create the ucontext. */
483 err |= __put_user(0, &frame->uc.uc_flags);
484 err |= __put_user(0, &frame->uc.uc_link);
485 err |= __save_altstack(&frame->uc.uc_stack, regs->regs[REG_SP]);
486 err |= setup_sigcontext(&frame->uc.uc_mcontext,
487 regs, set->sig[0]);
488 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
489
490 /* Give up earlier as i386, in case */
491 if (err)
492 return -EFAULT;
493
494 /* Set up to return from userspace. If provided, use a stub
495 already in userspace. */
496 if (ksig->ka.sa.sa_flags & SA_RESTORER) {
497 /*
498 * On SH5 all edited pointers are subject to NEFF
499 */
500 DEREF_REG_PR = neff_sign_extend((unsigned long)
501 ksig->ka.sa.sa_restorer | 0x1);
502 } else {
503 /*
504 * Different approach on SH5.
505 * . Endianness independent asm code gets placed in entry.S .
506 * This is limited to four ASM instructions corresponding
507 * to two long longs in size.
508 * . err checking is done on the else branch only
509 * . flush_icache_range() is called upon __put_user() only
510 * . all edited pointers are subject to NEFF
511 * . being code, linker turns ShMedia bit on, always
512 * dereference index -1.
513 */
514 DEREF_REG_PR = neff_sign_extend((unsigned long)
515 frame->retcode | 0x01);
516
517 if (__copy_to_user(frame->retcode,
518 (void *)((unsigned long)sa_default_rt_restorer & (~1)), 16) != 0)
519 return -EFAULT;
520
521 /* Cohere the trampoline with the I-cache. */
522 flush_icache_range(DEREF_REG_PR-1, DEREF_REG_PR-1+15);
523 }
524
525 /*
526 * Set up registers for signal handler.
527 * All edited pointers are subject to NEFF.
528 */
529 regs->regs[REG_SP] = neff_sign_extend((unsigned long)frame);
530 regs->regs[REG_ARG1] = sig; /* Arg for signal handler */
531 regs->regs[REG_ARG2] = (unsigned long long)(unsigned long)(signed long)&frame->info;
532 regs->regs[REG_ARG3] = (unsigned long long)(unsigned long)(signed long)&frame->uc.uc_mcontext;
533 regs->pc = neff_sign_extend((unsigned long)ksig->ka.sa.sa_handler);
534
535 pr_debug("SIG deliver (#%d,%s:%d): sp=%p pc=%08Lx%08Lx link=%08Lx%08Lx\n",
536 sig, current->comm, current->pid, frame,
537 regs->pc >> 32, regs->pc & 0xffffffff,
538 DEREF_REG_PR >> 32, DEREF_REG_PR & 0xffffffff);
539
540 return 0;
541 }
542
543 /*
544 * OK, we're invoking a handler
545 */
546 static void
handle_signal(struct ksignal * ksig,struct pt_regs * regs)547 handle_signal(struct ksignal *ksig, struct pt_regs *regs)
548 {
549 sigset_t *oldset = sigmask_to_save();
550 int ret;
551
552 /* Set up the stack frame */
553 if (ksig->ka.sa.sa_flags & SA_SIGINFO)
554 ret = setup_rt_frame(ksig, oldset, regs);
555 else
556 ret = setup_frame(ksig, oldset, regs);
557
558 signal_setup_done(ret, ksig, test_thread_flag(TIF_SINGLESTEP));
559 }
560
do_notify_resume(struct pt_regs * regs,unsigned long thread_info_flags)561 asmlinkage void do_notify_resume(struct pt_regs *regs, unsigned long thread_info_flags)
562 {
563 if (thread_info_flags & _TIF_SIGPENDING)
564 do_signal(regs);
565
566 if (thread_info_flags & _TIF_NOTIFY_RESUME) {
567 clear_thread_flag(TIF_NOTIFY_RESUME);
568 tracehook_notify_resume(regs);
569 }
570 }
571