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1da177e4 LT |
1 | /* |
2 | * arch/s390/kernel/signal.c | |
3 | * | |
4 | * S390 version | |
5 | * Copyright (C) 1999,2000 IBM Deutschland Entwicklung GmbH, IBM Corporation | |
6 | * Author(s): Denis Joseph Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com) | |
7 | * | |
8 | * Based on Intel version | |
9 | * | |
10 | * Copyright (C) 1991, 1992 Linus Torvalds | |
11 | * | |
12 | * 1997-11-28 Modified for POSIX.1b signals by Richard Henderson | |
13 | */ | |
14 | ||
15 | #include <linux/config.h> | |
16 | #include <linux/sched.h> | |
17 | #include <linux/mm.h> | |
18 | #include <linux/smp.h> | |
19 | #include <linux/smp_lock.h> | |
20 | #include <linux/kernel.h> | |
21 | #include <linux/signal.h> | |
22 | #include <linux/errno.h> | |
23 | #include <linux/wait.h> | |
24 | #include <linux/ptrace.h> | |
25 | #include <linux/unistd.h> | |
26 | #include <linux/stddef.h> | |
27 | #include <linux/tty.h> | |
28 | #include <linux/personality.h> | |
29 | #include <linux/binfmts.h> | |
30 | #include <asm/ucontext.h> | |
31 | #include <asm/uaccess.h> | |
32 | #include <asm/lowcore.h> | |
33 | ||
34 | #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP))) | |
35 | ||
36 | ||
37 | typedef struct | |
38 | { | |
39 | __u8 callee_used_stack[__SIGNAL_FRAMESIZE]; | |
40 | struct sigcontext sc; | |
41 | _sigregs sregs; | |
42 | int signo; | |
43 | __u8 retcode[S390_SYSCALL_SIZE]; | |
44 | } sigframe; | |
45 | ||
46 | typedef struct | |
47 | { | |
48 | __u8 callee_used_stack[__SIGNAL_FRAMESIZE]; | |
49 | __u8 retcode[S390_SYSCALL_SIZE]; | |
50 | struct siginfo info; | |
51 | struct ucontext uc; | |
52 | } rt_sigframe; | |
53 | ||
54 | int do_signal(struct pt_regs *regs, sigset_t *oldset); | |
55 | ||
56 | /* | |
57 | * Atomically swap in the new signal mask, and wait for a signal. | |
58 | */ | |
59 | asmlinkage int | |
60 | sys_sigsuspend(struct pt_regs * regs, int history0, int history1, | |
61 | old_sigset_t mask) | |
62 | { | |
63 | sigset_t saveset; | |
64 | ||
65 | mask &= _BLOCKABLE; | |
66 | spin_lock_irq(¤t->sighand->siglock); | |
67 | saveset = current->blocked; | |
68 | siginitset(¤t->blocked, mask); | |
69 | recalc_sigpending(); | |
70 | spin_unlock_irq(¤t->sighand->siglock); | |
71 | regs->gprs[2] = -EINTR; | |
72 | ||
73 | while (1) { | |
74 | set_current_state(TASK_INTERRUPTIBLE); | |
75 | schedule(); | |
76 | if (do_signal(regs, &saveset)) | |
77 | return -EINTR; | |
78 | } | |
79 | } | |
80 | ||
81 | asmlinkage long | |
82 | sys_rt_sigsuspend(struct pt_regs *regs, sigset_t __user *unewset, | |
83 | size_t sigsetsize) | |
84 | { | |
85 | sigset_t saveset, newset; | |
86 | ||
87 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
88 | if (sigsetsize != sizeof(sigset_t)) | |
89 | return -EINVAL; | |
90 | ||
91 | if (copy_from_user(&newset, unewset, sizeof(newset))) | |
92 | return -EFAULT; | |
93 | sigdelsetmask(&newset, ~_BLOCKABLE); | |
94 | ||
95 | spin_lock_irq(¤t->sighand->siglock); | |
96 | saveset = current->blocked; | |
97 | current->blocked = newset; | |
98 | recalc_sigpending(); | |
99 | spin_unlock_irq(¤t->sighand->siglock); | |
100 | regs->gprs[2] = -EINTR; | |
101 | ||
102 | while (1) { | |
103 | set_current_state(TASK_INTERRUPTIBLE); | |
104 | schedule(); | |
105 | if (do_signal(regs, &saveset)) | |
106 | return -EINTR; | |
107 | } | |
108 | } | |
109 | ||
110 | asmlinkage long | |
111 | sys_sigaction(int sig, const struct old_sigaction __user *act, | |
112 | struct old_sigaction __user *oact) | |
113 | { | |
114 | struct k_sigaction new_ka, old_ka; | |
115 | int ret; | |
116 | ||
117 | if (act) { | |
118 | old_sigset_t mask; | |
119 | if (!access_ok(VERIFY_READ, act, sizeof(*act)) || | |
120 | __get_user(new_ka.sa.sa_handler, &act->sa_handler) || | |
121 | __get_user(new_ka.sa.sa_restorer, &act->sa_restorer)) | |
122 | return -EFAULT; | |
123 | __get_user(new_ka.sa.sa_flags, &act->sa_flags); | |
124 | __get_user(mask, &act->sa_mask); | |
125 | siginitset(&new_ka.sa.sa_mask, mask); | |
126 | } | |
127 | ||
128 | ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL); | |
129 | ||
130 | if (!ret && oact) { | |
131 | if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) || | |
132 | __put_user(old_ka.sa.sa_handler, &oact->sa_handler) || | |
133 | __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer)) | |
134 | return -EFAULT; | |
135 | __put_user(old_ka.sa.sa_flags, &oact->sa_flags); | |
136 | __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask); | |
137 | } | |
138 | ||
139 | return ret; | |
140 | } | |
141 | ||
142 | asmlinkage long | |
143 | sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss, | |
144 | struct pt_regs *regs) | |
145 | { | |
146 | return do_sigaltstack(uss, uoss, regs->gprs[15]); | |
147 | } | |
148 | ||
149 | ||
150 | ||
151 | /* Returns non-zero on fault. */ | |
152 | static int save_sigregs(struct pt_regs *regs, _sigregs __user *sregs) | |
153 | { | |
154 | unsigned long old_mask = regs->psw.mask; | |
155 | int err; | |
156 | ||
157 | save_access_regs(current->thread.acrs); | |
158 | ||
159 | /* Copy a 'clean' PSW mask to the user to avoid leaking | |
160 | information about whether PER is currently on. */ | |
161 | regs->psw.mask = PSW_MASK_MERGE(PSW_USER_BITS, regs->psw.mask); | |
162 | err = __copy_to_user(&sregs->regs.psw, ®s->psw, | |
163 | sizeof(sregs->regs.psw)+sizeof(sregs->regs.gprs)); | |
164 | regs->psw.mask = old_mask; | |
165 | if (err != 0) | |
166 | return err; | |
167 | err = __copy_to_user(&sregs->regs.acrs, current->thread.acrs, | |
168 | sizeof(sregs->regs.acrs)); | |
169 | if (err != 0) | |
170 | return err; | |
171 | /* | |
172 | * We have to store the fp registers to current->thread.fp_regs | |
173 | * to merge them with the emulated registers. | |
174 | */ | |
175 | save_fp_regs(¤t->thread.fp_regs); | |
176 | return __copy_to_user(&sregs->fpregs, ¤t->thread.fp_regs, | |
177 | sizeof(s390_fp_regs)); | |
178 | } | |
179 | ||
180 | /* Returns positive number on error */ | |
181 | static int restore_sigregs(struct pt_regs *regs, _sigregs __user *sregs) | |
182 | { | |
183 | unsigned long old_mask = regs->psw.mask; | |
184 | int err; | |
185 | ||
186 | /* Alwys make any pending restarted system call return -EINTR */ | |
187 | current_thread_info()->restart_block.fn = do_no_restart_syscall; | |
188 | ||
189 | err = __copy_from_user(®s->psw, &sregs->regs.psw, | |
190 | sizeof(sregs->regs.psw)+sizeof(sregs->regs.gprs)); | |
191 | regs->psw.mask = PSW_MASK_MERGE(old_mask, regs->psw.mask); | |
192 | regs->psw.addr |= PSW_ADDR_AMODE; | |
193 | if (err) | |
194 | return err; | |
195 | err = __copy_from_user(¤t->thread.acrs, &sregs->regs.acrs, | |
196 | sizeof(sregs->regs.acrs)); | |
197 | if (err) | |
198 | return err; | |
199 | restore_access_regs(current->thread.acrs); | |
200 | ||
201 | err = __copy_from_user(¤t->thread.fp_regs, &sregs->fpregs, | |
202 | sizeof(s390_fp_regs)); | |
203 | current->thread.fp_regs.fpc &= FPC_VALID_MASK; | |
204 | if (err) | |
205 | return err; | |
206 | ||
207 | restore_fp_regs(¤t->thread.fp_regs); | |
208 | regs->trap = -1; /* disable syscall checks */ | |
209 | return 0; | |
210 | } | |
211 | ||
212 | asmlinkage long sys_sigreturn(struct pt_regs *regs) | |
213 | { | |
214 | sigframe __user *frame = (sigframe __user *)regs->gprs[15]; | |
215 | sigset_t set; | |
216 | ||
217 | if (!access_ok(VERIFY_READ, frame, sizeof(*frame))) | |
218 | goto badframe; | |
219 | if (__copy_from_user(&set.sig, &frame->sc.oldmask, _SIGMASK_COPY_SIZE)) | |
220 | goto badframe; | |
221 | ||
222 | sigdelsetmask(&set, ~_BLOCKABLE); | |
223 | spin_lock_irq(¤t->sighand->siglock); | |
224 | current->blocked = set; | |
225 | recalc_sigpending(); | |
226 | spin_unlock_irq(¤t->sighand->siglock); | |
227 | ||
228 | if (restore_sigregs(regs, &frame->sregs)) | |
229 | goto badframe; | |
230 | ||
231 | return regs->gprs[2]; | |
232 | ||
233 | badframe: | |
234 | force_sig(SIGSEGV, current); | |
235 | return 0; | |
236 | } | |
237 | ||
238 | asmlinkage long sys_rt_sigreturn(struct pt_regs *regs) | |
239 | { | |
240 | rt_sigframe __user *frame = (rt_sigframe __user *)regs->gprs[15]; | |
241 | sigset_t set; | |
242 | ||
243 | if (!access_ok(VERIFY_READ, frame, sizeof(*frame))) | |
244 | goto badframe; | |
245 | if (__copy_from_user(&set.sig, &frame->uc.uc_sigmask, sizeof(set))) | |
246 | goto badframe; | |
247 | ||
248 | sigdelsetmask(&set, ~_BLOCKABLE); | |
249 | spin_lock_irq(¤t->sighand->siglock); | |
250 | current->blocked = set; | |
251 | recalc_sigpending(); | |
252 | spin_unlock_irq(¤t->sighand->siglock); | |
253 | ||
254 | if (restore_sigregs(regs, &frame->uc.uc_mcontext)) | |
255 | goto badframe; | |
256 | ||
4e3df37e CLG |
257 | if (do_sigaltstack(&frame->uc.uc_stack, NULL, |
258 | regs->gprs[15]) == -EFAULT) | |
259 | goto badframe; | |
1da177e4 LT |
260 | return regs->gprs[2]; |
261 | ||
262 | badframe: | |
263 | force_sig(SIGSEGV, current); | |
264 | return 0; | |
265 | } | |
266 | ||
267 | /* | |
268 | * Set up a signal frame. | |
269 | */ | |
270 | ||
271 | ||
272 | /* | |
273 | * Determine which stack to use.. | |
274 | */ | |
275 | static inline void __user * | |
276 | get_sigframe(struct k_sigaction *ka, struct pt_regs * regs, size_t frame_size) | |
277 | { | |
278 | unsigned long sp; | |
279 | ||
280 | /* Default to using normal stack */ | |
281 | sp = regs->gprs[15]; | |
282 | ||
283 | /* This is the X/Open sanctioned signal stack switching. */ | |
284 | if (ka->sa.sa_flags & SA_ONSTACK) { | |
285 | if (! sas_ss_flags(sp)) | |
286 | sp = current->sas_ss_sp + current->sas_ss_size; | |
287 | } | |
288 | ||
289 | /* This is the legacy signal stack switching. */ | |
290 | else if (!user_mode(regs) && | |
291 | !(ka->sa.sa_flags & SA_RESTORER) && | |
292 | ka->sa.sa_restorer) { | |
293 | sp = (unsigned long) ka->sa.sa_restorer; | |
294 | } | |
295 | ||
296 | return (void __user *)((sp - frame_size) & -8ul); | |
297 | } | |
298 | ||
299 | static inline int map_signal(int sig) | |
300 | { | |
301 | if (current_thread_info()->exec_domain | |
302 | && current_thread_info()->exec_domain->signal_invmap | |
303 | && sig < 32) | |
304 | return current_thread_info()->exec_domain->signal_invmap[sig]; | |
305 | else | |
306 | return sig; | |
307 | } | |
308 | ||
309 | static void setup_frame(int sig, struct k_sigaction *ka, | |
310 | sigset_t *set, struct pt_regs * regs) | |
311 | { | |
312 | sigframe __user *frame; | |
313 | ||
314 | frame = get_sigframe(ka, regs, sizeof(sigframe)); | |
315 | if (!access_ok(VERIFY_WRITE, frame, sizeof(sigframe))) | |
316 | goto give_sigsegv; | |
317 | ||
318 | if (__copy_to_user(&frame->sc.oldmask, &set->sig, _SIGMASK_COPY_SIZE)) | |
319 | goto give_sigsegv; | |
320 | ||
321 | if (save_sigregs(regs, &frame->sregs)) | |
322 | goto give_sigsegv; | |
323 | if (__put_user(&frame->sregs, &frame->sc.sregs)) | |
324 | goto give_sigsegv; | |
325 | ||
326 | /* Set up to return from userspace. If provided, use a stub | |
327 | already in userspace. */ | |
328 | if (ka->sa.sa_flags & SA_RESTORER) { | |
329 | regs->gprs[14] = (unsigned long) | |
330 | ka->sa.sa_restorer | PSW_ADDR_AMODE; | |
331 | } else { | |
332 | regs->gprs[14] = (unsigned long) | |
333 | frame->retcode | PSW_ADDR_AMODE; | |
334 | if (__put_user(S390_SYSCALL_OPCODE | __NR_sigreturn, | |
335 | (u16 __user *)(frame->retcode))) | |
336 | goto give_sigsegv; | |
337 | } | |
338 | ||
339 | /* Set up backchain. */ | |
340 | if (__put_user(regs->gprs[15], (addr_t __user *) frame)) | |
341 | goto give_sigsegv; | |
342 | ||
343 | /* Set up registers for signal handler */ | |
344 | regs->gprs[15] = (unsigned long) frame; | |
345 | regs->psw.addr = (unsigned long) ka->sa.sa_handler | PSW_ADDR_AMODE; | |
346 | ||
347 | regs->gprs[2] = map_signal(sig); | |
348 | regs->gprs[3] = (unsigned long) &frame->sc; | |
349 | ||
350 | /* We forgot to include these in the sigcontext. | |
351 | To avoid breaking binary compatibility, they are passed as args. */ | |
352 | regs->gprs[4] = current->thread.trap_no; | |
353 | regs->gprs[5] = current->thread.prot_addr; | |
354 | ||
355 | /* Place signal number on stack to allow backtrace from handler. */ | |
356 | if (__put_user(regs->gprs[2], (int __user *) &frame->signo)) | |
357 | goto give_sigsegv; | |
358 | return; | |
359 | ||
360 | give_sigsegv: | |
361 | force_sigsegv(sig, current); | |
362 | } | |
363 | ||
364 | static void setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info, | |
365 | sigset_t *set, struct pt_regs * regs) | |
366 | { | |
367 | int err = 0; | |
368 | rt_sigframe __user *frame; | |
369 | ||
370 | frame = get_sigframe(ka, regs, sizeof(rt_sigframe)); | |
371 | if (!access_ok(VERIFY_WRITE, frame, sizeof(rt_sigframe))) | |
372 | goto give_sigsegv; | |
373 | ||
374 | if (copy_siginfo_to_user(&frame->info, info)) | |
375 | goto give_sigsegv; | |
376 | ||
377 | /* Create the ucontext. */ | |
378 | err |= __put_user(0, &frame->uc.uc_flags); | |
c2814476 AV |
379 | err |= __put_user(NULL, &frame->uc.uc_link); |
380 | err |= __put_user((void __user *)current->sas_ss_sp, &frame->uc.uc_stack.ss_sp); | |
1da177e4 LT |
381 | err |= __put_user(sas_ss_flags(regs->gprs[15]), |
382 | &frame->uc.uc_stack.ss_flags); | |
383 | err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size); | |
384 | err |= save_sigregs(regs, &frame->uc.uc_mcontext); | |
385 | err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)); | |
386 | if (err) | |
387 | goto give_sigsegv; | |
388 | ||
389 | /* Set up to return from userspace. If provided, use a stub | |
390 | already in userspace. */ | |
391 | if (ka->sa.sa_flags & SA_RESTORER) { | |
392 | regs->gprs[14] = (unsigned long) | |
393 | ka->sa.sa_restorer | PSW_ADDR_AMODE; | |
394 | } else { | |
395 | regs->gprs[14] = (unsigned long) | |
396 | frame->retcode | PSW_ADDR_AMODE; | |
397 | err |= __put_user(S390_SYSCALL_OPCODE | __NR_rt_sigreturn, | |
398 | (u16 __user *)(frame->retcode)); | |
399 | } | |
400 | ||
401 | /* Set up backchain. */ | |
402 | if (__put_user(regs->gprs[15], (addr_t __user *) frame)) | |
403 | goto give_sigsegv; | |
404 | ||
405 | /* Set up registers for signal handler */ | |
406 | regs->gprs[15] = (unsigned long) frame; | |
407 | regs->psw.addr = (unsigned long) ka->sa.sa_handler | PSW_ADDR_AMODE; | |
408 | ||
409 | regs->gprs[2] = map_signal(sig); | |
410 | regs->gprs[3] = (unsigned long) &frame->info; | |
411 | regs->gprs[4] = (unsigned long) &frame->uc; | |
412 | return; | |
413 | ||
414 | give_sigsegv: | |
415 | force_sigsegv(sig, current); | |
416 | } | |
417 | ||
418 | /* | |
419 | * OK, we're invoking a handler | |
420 | */ | |
421 | ||
422 | static void | |
423 | handle_signal(unsigned long sig, struct k_sigaction *ka, | |
424 | siginfo_t *info, sigset_t *oldset, struct pt_regs * regs) | |
425 | { | |
426 | /* Set up the stack frame */ | |
427 | if (ka->sa.sa_flags & SA_SIGINFO) | |
428 | setup_rt_frame(sig, ka, info, oldset, regs); | |
429 | else | |
430 | setup_frame(sig, ka, oldset, regs); | |
431 | ||
69be8f18 SR |
432 | spin_lock_irq(¤t->sighand->siglock); |
433 | sigorsets(¤t->blocked,¤t->blocked,&ka->sa.sa_mask); | |
434 | if (!(ka->sa.sa_flags & SA_NODEFER)) | |
1da177e4 | 435 | sigaddset(¤t->blocked,sig); |
69be8f18 SR |
436 | recalc_sigpending(); |
437 | spin_unlock_irq(¤t->sighand->siglock); | |
1da177e4 LT |
438 | } |
439 | ||
440 | /* | |
441 | * Note that 'init' is a special process: it doesn't get signals it doesn't | |
442 | * want to handle. Thus you cannot kill init even with a SIGKILL even by | |
443 | * mistake. | |
444 | * | |
445 | * Note that we go through the signals twice: once to check the signals that | |
446 | * the kernel can handle, and then we build all the user-level signal handling | |
447 | * stack-frames in one go after that. | |
448 | */ | |
449 | int do_signal(struct pt_regs *regs, sigset_t *oldset) | |
450 | { | |
451 | unsigned long retval = 0, continue_addr = 0, restart_addr = 0; | |
452 | siginfo_t info; | |
453 | int signr; | |
454 | struct k_sigaction ka; | |
455 | ||
456 | /* | |
457 | * We want the common case to go fast, which | |
458 | * is why we may in certain cases get here from | |
459 | * kernel mode. Just return without doing anything | |
460 | * if so. | |
461 | */ | |
462 | if (!user_mode(regs)) | |
463 | return 1; | |
464 | ||
465 | if (!oldset) | |
466 | oldset = ¤t->blocked; | |
467 | ||
468 | /* Are we from a system call? */ | |
469 | if (regs->trap == __LC_SVC_OLD_PSW) { | |
470 | continue_addr = regs->psw.addr; | |
471 | restart_addr = continue_addr - regs->ilc; | |
472 | retval = regs->gprs[2]; | |
473 | ||
474 | /* Prepare for system call restart. We do this here so that a | |
475 | debugger will see the already changed PSW. */ | |
476 | if (retval == -ERESTARTNOHAND || | |
477 | retval == -ERESTARTSYS || | |
478 | retval == -ERESTARTNOINTR) { | |
479 | regs->gprs[2] = regs->orig_gpr2; | |
480 | regs->psw.addr = restart_addr; | |
481 | } else if (retval == -ERESTART_RESTARTBLOCK) { | |
482 | regs->gprs[2] = -EINTR; | |
483 | } | |
484 | } | |
485 | ||
486 | /* Get signal to deliver. When running under ptrace, at this point | |
487 | the debugger may change all our registers ... */ | |
488 | signr = get_signal_to_deliver(&info, &ka, regs, NULL); | |
489 | ||
490 | /* Depending on the signal settings we may need to revert the | |
491 | decision to restart the system call. */ | |
492 | if (signr > 0 && regs->psw.addr == restart_addr) { | |
493 | if (retval == -ERESTARTNOHAND | |
494 | || (retval == -ERESTARTSYS | |
495 | && !(current->sighand->action[signr-1].sa.sa_flags | |
496 | & SA_RESTART))) { | |
497 | regs->gprs[2] = -EINTR; | |
498 | regs->psw.addr = continue_addr; | |
499 | } | |
500 | } | |
501 | ||
502 | if (signr > 0) { | |
503 | /* Whee! Actually deliver the signal. */ | |
347a8dc3 | 504 | #ifdef CONFIG_COMPAT |
1da177e4 LT |
505 | if (test_thread_flag(TIF_31BIT)) { |
506 | extern void handle_signal32(unsigned long sig, | |
507 | struct k_sigaction *ka, | |
508 | siginfo_t *info, | |
509 | sigset_t *oldset, | |
510 | struct pt_regs *regs); | |
511 | handle_signal32(signr, &ka, &info, oldset, regs); | |
512 | return 1; | |
513 | } | |
514 | #endif | |
515 | handle_signal(signr, &ka, &info, oldset, regs); | |
516 | return 1; | |
517 | } | |
518 | ||
519 | /* Restart a different system call. */ | |
520 | if (retval == -ERESTART_RESTARTBLOCK | |
521 | && regs->psw.addr == continue_addr) { | |
522 | regs->gprs[2] = __NR_restart_syscall; | |
523 | set_thread_flag(TIF_RESTART_SVC); | |
524 | } | |
525 | return 0; | |
526 | } |