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1da177e4 LT |
1 | /* |
2 | * linux/arch/x86_64/kernel/signal.c | |
3 | * | |
4 | * Copyright (C) 1991, 1992 Linus Torvalds | |
5 | * Copyright (C) 2000, 2001, 2002 Andi Kleen SuSE Labs | |
6 | * | |
7 | * 1997-11-28 Modified for POSIX.1b signals by Richard Henderson | |
8 | * 2000-06-20 Pentium III FXSR, SSE support by Gareth Hughes | |
9 | * 2000-2002 x86-64 support by Andi Kleen | |
10 | * | |
11 | * $Id: signal.c,v 1.18 2001/10/17 22:30:37 ak Exp $ | |
12 | */ | |
13 | ||
14 | #include <linux/sched.h> | |
15 | #include <linux/mm.h> | |
16 | #include <linux/smp.h> | |
17 | #include <linux/smp_lock.h> | |
18 | #include <linux/kernel.h> | |
19 | #include <linux/signal.h> | |
20 | #include <linux/errno.h> | |
21 | #include <linux/wait.h> | |
22 | #include <linux/ptrace.h> | |
23 | #include <linux/unistd.h> | |
24 | #include <linux/stddef.h> | |
25 | #include <linux/personality.h> | |
26 | #include <linux/compiler.h> | |
27 | #include <asm/ucontext.h> | |
28 | #include <asm/uaccess.h> | |
29 | #include <asm/i387.h> | |
30 | #include <asm/proto.h> | |
c5924b7d | 31 | #include <asm/ia32_unistd.h> |
1da177e4 LT |
32 | |
33 | /* #define DEBUG_SIG 1 */ | |
34 | ||
35 | #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP))) | |
36 | ||
0928d6ef | 37 | int ia32_setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info, |
1da177e4 | 38 | sigset_t *set, struct pt_regs * regs); |
0928d6ef | 39 | int ia32_setup_frame(int sig, struct k_sigaction *ka, |
1da177e4 LT |
40 | sigset_t *set, struct pt_regs * regs); |
41 | ||
42 | asmlinkage long | |
43 | sys_rt_sigsuspend(sigset_t __user *unewset, size_t sigsetsize, struct pt_regs *regs) | |
44 | { | |
45 | sigset_t saveset, newset; | |
46 | ||
47 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
48 | if (sigsetsize != sizeof(sigset_t)) | |
49 | return -EINVAL; | |
50 | ||
51 | if (copy_from_user(&newset, unewset, sizeof(newset))) | |
52 | return -EFAULT; | |
53 | sigdelsetmask(&newset, ~_BLOCKABLE); | |
54 | ||
55 | spin_lock_irq(¤t->sighand->siglock); | |
56 | saveset = current->blocked; | |
57 | current->blocked = newset; | |
58 | recalc_sigpending(); | |
59 | spin_unlock_irq(¤t->sighand->siglock); | |
60 | #ifdef DEBUG_SIG | |
61 | printk("rt_sigsuspend savset(%lx) newset(%lx) regs(%p) rip(%lx)\n", | |
62 | saveset, newset, regs, regs->rip); | |
63 | #endif | |
64 | regs->rax = -EINTR; | |
65 | while (1) { | |
66 | current->state = TASK_INTERRUPTIBLE; | |
67 | schedule(); | |
68 | if (do_signal(regs, &saveset)) | |
69 | return -EINTR; | |
70 | } | |
71 | } | |
72 | ||
73 | asmlinkage long | |
74 | sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss, | |
75 | struct pt_regs *regs) | |
76 | { | |
77 | return do_sigaltstack(uss, uoss, regs->rsp); | |
78 | } | |
79 | ||
80 | ||
81 | /* | |
82 | * Do a signal return; undo the signal stack. | |
83 | */ | |
84 | ||
85 | struct rt_sigframe | |
86 | { | |
993fb38b | 87 | char __user *pretcode; |
1da177e4 LT |
88 | struct ucontext uc; |
89 | struct siginfo info; | |
90 | }; | |
91 | ||
92 | static int | |
93 | restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc, unsigned long *prax) | |
94 | { | |
95 | unsigned int err = 0; | |
96 | ||
97 | /* Always make any pending restarted system calls return -EINTR */ | |
98 | current_thread_info()->restart_block.fn = do_no_restart_syscall; | |
99 | ||
100 | #define COPY(x) err |= __get_user(regs->x, &sc->x) | |
101 | ||
102 | COPY(rdi); COPY(rsi); COPY(rbp); COPY(rsp); COPY(rbx); | |
103 | COPY(rdx); COPY(rcx); COPY(rip); | |
104 | COPY(r8); | |
105 | COPY(r9); | |
106 | COPY(r10); | |
107 | COPY(r11); | |
108 | COPY(r12); | |
109 | COPY(r13); | |
110 | COPY(r14); | |
111 | COPY(r15); | |
112 | ||
113 | { | |
114 | unsigned int tmpflags; | |
115 | err |= __get_user(tmpflags, &sc->eflags); | |
116 | regs->eflags = (regs->eflags & ~0x40DD5) | (tmpflags & 0x40DD5); | |
117 | regs->orig_rax = -1; /* disable syscall checks */ | |
118 | } | |
119 | ||
120 | { | |
121 | struct _fpstate __user * buf; | |
122 | err |= __get_user(buf, &sc->fpstate); | |
123 | ||
124 | if (buf) { | |
125 | if (!access_ok(VERIFY_READ, buf, sizeof(*buf))) | |
126 | goto badframe; | |
127 | err |= restore_i387(buf); | |
128 | } else { | |
129 | struct task_struct *me = current; | |
130 | if (used_math()) { | |
131 | clear_fpu(me); | |
132 | clear_used_math(); | |
133 | } | |
134 | } | |
135 | } | |
136 | ||
137 | err |= __get_user(*prax, &sc->rax); | |
138 | return err; | |
139 | ||
140 | badframe: | |
141 | return 1; | |
142 | } | |
143 | ||
144 | asmlinkage long sys_rt_sigreturn(struct pt_regs *regs) | |
145 | { | |
146 | struct rt_sigframe __user *frame; | |
147 | sigset_t set; | |
148 | unsigned long eax; | |
149 | ||
150 | frame = (struct rt_sigframe __user *)(regs->rsp - 8); | |
151 | if (!access_ok(VERIFY_READ, frame, sizeof(*frame))) { | |
152 | goto badframe; | |
153 | } | |
154 | if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set))) { | |
155 | goto badframe; | |
156 | } | |
157 | ||
158 | sigdelsetmask(&set, ~_BLOCKABLE); | |
159 | spin_lock_irq(¤t->sighand->siglock); | |
160 | current->blocked = set; | |
161 | recalc_sigpending(); | |
162 | spin_unlock_irq(¤t->sighand->siglock); | |
163 | ||
164 | if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &eax)) | |
165 | goto badframe; | |
166 | ||
167 | #ifdef DEBUG_SIG | |
168 | printk("%d sigreturn rip:%lx rsp:%lx frame:%p rax:%lx\n",current->pid,regs.rip,regs.rsp,frame,eax); | |
169 | #endif | |
170 | ||
171 | if (do_sigaltstack(&frame->uc.uc_stack, NULL, regs->rsp) == -EFAULT) | |
172 | goto badframe; | |
173 | ||
174 | return eax; | |
175 | ||
176 | badframe: | |
177 | signal_fault(regs,frame,"sigreturn"); | |
178 | return 0; | |
179 | } | |
180 | ||
181 | /* | |
182 | * Set up a signal frame. | |
183 | */ | |
184 | ||
185 | static inline int | |
186 | setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs, unsigned long mask, struct task_struct *me) | |
187 | { | |
188 | int err = 0; | |
1da177e4 LT |
189 | |
190 | err |= __put_user(0, &sc->gs); | |
191 | err |= __put_user(0, &sc->fs); | |
192 | ||
193 | err |= __put_user(regs->rdi, &sc->rdi); | |
194 | err |= __put_user(regs->rsi, &sc->rsi); | |
195 | err |= __put_user(regs->rbp, &sc->rbp); | |
196 | err |= __put_user(regs->rsp, &sc->rsp); | |
197 | err |= __put_user(regs->rbx, &sc->rbx); | |
198 | err |= __put_user(regs->rdx, &sc->rdx); | |
199 | err |= __put_user(regs->rcx, &sc->rcx); | |
200 | err |= __put_user(regs->rax, &sc->rax); | |
201 | err |= __put_user(regs->r8, &sc->r8); | |
202 | err |= __put_user(regs->r9, &sc->r9); | |
203 | err |= __put_user(regs->r10, &sc->r10); | |
204 | err |= __put_user(regs->r11, &sc->r11); | |
205 | err |= __put_user(regs->r12, &sc->r12); | |
206 | err |= __put_user(regs->r13, &sc->r13); | |
207 | err |= __put_user(regs->r14, &sc->r14); | |
208 | err |= __put_user(regs->r15, &sc->r15); | |
209 | err |= __put_user(me->thread.trap_no, &sc->trapno); | |
210 | err |= __put_user(me->thread.error_code, &sc->err); | |
211 | err |= __put_user(regs->rip, &sc->rip); | |
be61bff7 | 212 | err |= __put_user(regs->eflags, &sc->eflags); |
1da177e4 LT |
213 | err |= __put_user(mask, &sc->oldmask); |
214 | err |= __put_user(me->thread.cr2, &sc->cr2); | |
215 | ||
216 | return err; | |
217 | } | |
218 | ||
219 | /* | |
220 | * Determine which stack to use.. | |
221 | */ | |
222 | ||
223 | static void __user * | |
224 | get_stack(struct k_sigaction *ka, struct pt_regs *regs, unsigned long size) | |
225 | { | |
226 | unsigned long rsp; | |
227 | ||
228 | /* Default to using normal stack - redzone*/ | |
229 | rsp = regs->rsp - 128; | |
230 | ||
231 | /* This is the X/Open sanctioned signal stack switching. */ | |
232 | /* RED-PEN: redzone on that stack? */ | |
233 | if (ka->sa.sa_flags & SA_ONSTACK) { | |
234 | if (sas_ss_flags(rsp) == 0) | |
235 | rsp = current->sas_ss_sp + current->sas_ss_size; | |
236 | } | |
237 | ||
238 | return (void __user *)round_down(rsp - size, 16); | |
239 | } | |
240 | ||
0928d6ef | 241 | static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info, |
1da177e4 LT |
242 | sigset_t *set, struct pt_regs * regs) |
243 | { | |
244 | struct rt_sigframe __user *frame; | |
245 | struct _fpstate __user *fp = NULL; | |
246 | int err = 0; | |
247 | struct task_struct *me = current; | |
248 | ||
249 | if (used_math()) { | |
250 | fp = get_stack(ka, regs, sizeof(struct _fpstate)); | |
251 | frame = (void __user *)round_down( | |
252 | (unsigned long)fp - sizeof(struct rt_sigframe), 16) - 8; | |
253 | ||
254 | if (!access_ok(VERIFY_WRITE, fp, sizeof(struct _fpstate))) | |
255 | goto give_sigsegv; | |
256 | ||
257 | if (save_i387(fp) < 0) | |
258 | err |= -1; | |
259 | } else | |
260 | frame = get_stack(ka, regs, sizeof(struct rt_sigframe)) - 8; | |
261 | ||
262 | if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) | |
263 | goto give_sigsegv; | |
264 | ||
265 | if (ka->sa.sa_flags & SA_SIGINFO) { | |
266 | err |= copy_siginfo_to_user(&frame->info, info); | |
267 | if (err) | |
268 | goto give_sigsegv; | |
269 | } | |
270 | ||
271 | /* Create the ucontext. */ | |
272 | err |= __put_user(0, &frame->uc.uc_flags); | |
273 | err |= __put_user(0, &frame->uc.uc_link); | |
274 | err |= __put_user(me->sas_ss_sp, &frame->uc.uc_stack.ss_sp); | |
275 | err |= __put_user(sas_ss_flags(regs->rsp), | |
276 | &frame->uc.uc_stack.ss_flags); | |
277 | err |= __put_user(me->sas_ss_size, &frame->uc.uc_stack.ss_size); | |
278 | err |= setup_sigcontext(&frame->uc.uc_mcontext, regs, set->sig[0], me); | |
279 | err |= __put_user(fp, &frame->uc.uc_mcontext.fpstate); | |
280 | if (sizeof(*set) == 16) { | |
281 | __put_user(set->sig[0], &frame->uc.uc_sigmask.sig[0]); | |
282 | __put_user(set->sig[1], &frame->uc.uc_sigmask.sig[1]); | |
283 | } else | |
284 | err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)); | |
285 | ||
286 | /* Set up to return from userspace. If provided, use a stub | |
287 | already in userspace. */ | |
288 | /* x86-64 should always use SA_RESTORER. */ | |
289 | if (ka->sa.sa_flags & SA_RESTORER) { | |
290 | err |= __put_user(ka->sa.sa_restorer, &frame->pretcode); | |
291 | } else { | |
292 | /* could use a vstub here */ | |
293 | goto give_sigsegv; | |
294 | } | |
295 | ||
296 | if (err) | |
297 | goto give_sigsegv; | |
298 | ||
299 | #ifdef DEBUG_SIG | |
300 | printk("%d old rip %lx old rsp %lx old rax %lx\n", current->pid,regs->rip,regs->rsp,regs->rax); | |
301 | #endif | |
302 | ||
303 | /* Set up registers for signal handler */ | |
304 | { | |
305 | struct exec_domain *ed = current_thread_info()->exec_domain; | |
306 | if (unlikely(ed && ed->signal_invmap && sig < 32)) | |
307 | sig = ed->signal_invmap[sig]; | |
308 | } | |
309 | regs->rdi = sig; | |
310 | /* In case the signal handler was declared without prototypes */ | |
311 | regs->rax = 0; | |
312 | ||
313 | /* This also works for non SA_SIGINFO handlers because they expect the | |
314 | next argument after the signal number on the stack. */ | |
315 | regs->rsi = (unsigned long)&frame->info; | |
316 | regs->rdx = (unsigned long)&frame->uc; | |
317 | regs->rip = (unsigned long) ka->sa.sa_handler; | |
318 | ||
319 | regs->rsp = (unsigned long)frame; | |
320 | ||
321 | set_fs(USER_DS); | |
be61bff7 AK |
322 | regs->eflags &= ~TF_MASK; |
323 | if (test_thread_flag(TIF_SINGLESTEP)) | |
324 | ptrace_notify(SIGTRAP); | |
1da177e4 LT |
325 | #ifdef DEBUG_SIG |
326 | printk("SIG deliver (%s:%d): sp=%p pc=%p ra=%p\n", | |
327 | current->comm, current->pid, frame, regs->rip, frame->pretcode); | |
328 | #endif | |
329 | ||
0928d6ef | 330 | return 1; |
1da177e4 LT |
331 | |
332 | give_sigsegv: | |
333 | force_sigsegv(sig, current); | |
0928d6ef | 334 | return 0; |
1da177e4 LT |
335 | } |
336 | ||
337 | /* | |
338 | * OK, we're invoking a handler | |
339 | */ | |
340 | ||
0928d6ef | 341 | static int |
1da177e4 LT |
342 | handle_signal(unsigned long sig, siginfo_t *info, struct k_sigaction *ka, |
343 | sigset_t *oldset, struct pt_regs *regs) | |
344 | { | |
0928d6ef RM |
345 | int ret; |
346 | ||
1da177e4 LT |
347 | #ifdef DEBUG_SIG |
348 | printk("handle_signal pid:%d sig:%lu rip:%lx rsp:%lx regs=%p\n", | |
349 | current->pid, sig, | |
350 | regs->rip, regs->rsp, regs); | |
351 | #endif | |
352 | ||
353 | /* Are we from a system call? */ | |
354 | if ((long)regs->orig_rax >= 0) { | |
355 | /* If so, check system call restarting.. */ | |
356 | switch (regs->rax) { | |
357 | case -ERESTART_RESTARTBLOCK: | |
358 | case -ERESTARTNOHAND: | |
359 | regs->rax = -EINTR; | |
360 | break; | |
361 | ||
362 | case -ERESTARTSYS: | |
363 | if (!(ka->sa.sa_flags & SA_RESTART)) { | |
364 | regs->rax = -EINTR; | |
365 | break; | |
366 | } | |
367 | /* fallthrough */ | |
368 | case -ERESTARTNOINTR: | |
369 | regs->rax = regs->orig_rax; | |
370 | regs->rip -= 2; | |
371 | break; | |
372 | } | |
373 | } | |
374 | ||
d61915da AK |
375 | /* |
376 | * If TF is set due to a debugger (PT_DTRACE), clear the TF | |
377 | * flag so that register information in the sigcontext is | |
378 | * correct. | |
379 | */ | |
380 | if (unlikely(regs->eflags & TF_MASK)) { | |
381 | if (likely(current->ptrace & PT_DTRACE)) { | |
382 | current->ptrace &= ~PT_DTRACE; | |
383 | regs->eflags &= ~TF_MASK; | |
384 | } | |
385 | } | |
386 | ||
1da177e4 LT |
387 | #ifdef CONFIG_IA32_EMULATION |
388 | if (test_thread_flag(TIF_IA32)) { | |
389 | if (ka->sa.sa_flags & SA_SIGINFO) | |
0928d6ef | 390 | ret = ia32_setup_rt_frame(sig, ka, info, oldset, regs); |
1da177e4 | 391 | else |
0928d6ef | 392 | ret = ia32_setup_frame(sig, ka, oldset, regs); |
1da177e4 LT |
393 | } else |
394 | #endif | |
0928d6ef | 395 | ret = setup_rt_frame(sig, ka, info, oldset, regs); |
1da177e4 | 396 | |
69be8f18 | 397 | if (ret) { |
1da177e4 LT |
398 | spin_lock_irq(¤t->sighand->siglock); |
399 | sigorsets(¤t->blocked,¤t->blocked,&ka->sa.sa_mask); | |
69be8f18 SR |
400 | if (!(ka->sa.sa_flags & SA_NODEFER)) |
401 | sigaddset(¤t->blocked,sig); | |
1da177e4 LT |
402 | recalc_sigpending(); |
403 | spin_unlock_irq(¤t->sighand->siglock); | |
404 | } | |
0928d6ef RM |
405 | |
406 | return ret; | |
1da177e4 LT |
407 | } |
408 | ||
409 | /* | |
410 | * Note that 'init' is a special process: it doesn't get signals it doesn't | |
411 | * want to handle. Thus you cannot kill init even with a SIGKILL even by | |
412 | * mistake. | |
413 | */ | |
414 | int do_signal(struct pt_regs *regs, sigset_t *oldset) | |
415 | { | |
416 | struct k_sigaction ka; | |
417 | siginfo_t info; | |
418 | int signr; | |
419 | ||
420 | /* | |
421 | * We want the common case to go fast, which | |
422 | * is why we may in certain cases get here from | |
423 | * kernel mode. Just return without doing anything | |
424 | * if so. | |
425 | */ | |
76381fee | 426 | if (!user_mode(regs)) |
1da177e4 LT |
427 | return 1; |
428 | ||
3e1d1d28 | 429 | if (try_to_freeze()) |
1da177e4 LT |
430 | goto no_signal; |
431 | ||
432 | if (!oldset) | |
433 | oldset = ¤t->blocked; | |
434 | ||
435 | signr = get_signal_to_deliver(&info, &ka, regs, NULL); | |
436 | if (signr > 0) { | |
437 | /* Reenable any watchpoints before delivering the | |
438 | * signal to user space. The processor register will | |
439 | * have been cleared if the watchpoint triggered | |
440 | * inside the kernel. | |
441 | */ | |
442 | if (current->thread.debugreg7) | |
e9129e56 | 443 | set_debugreg(current->thread.debugreg7, 7); |
1da177e4 LT |
444 | |
445 | /* Whee! Actually deliver the signal. */ | |
0928d6ef | 446 | return handle_signal(signr, &info, &ka, oldset, regs); |
1da177e4 LT |
447 | } |
448 | ||
449 | no_signal: | |
450 | /* Did we come from a system call? */ | |
451 | if ((long)regs->orig_rax >= 0) { | |
452 | /* Restart the system call - no handlers present */ | |
453 | long res = regs->rax; | |
454 | if (res == -ERESTARTNOHAND || | |
455 | res == -ERESTARTSYS || | |
456 | res == -ERESTARTNOINTR) { | |
457 | regs->rax = regs->orig_rax; | |
458 | regs->rip -= 2; | |
459 | } | |
460 | if (regs->rax == (unsigned long)-ERESTART_RESTARTBLOCK) { | |
607a1685 AK |
461 | regs->rax = test_thread_flag(TIF_IA32) ? |
462 | __NR_ia32_restart_syscall : | |
463 | __NR_restart_syscall; | |
1da177e4 LT |
464 | regs->rip -= 2; |
465 | } | |
466 | } | |
467 | return 0; | |
468 | } | |
469 | ||
470 | void do_notify_resume(struct pt_regs *regs, sigset_t *oldset, __u32 thread_info_flags) | |
471 | { | |
472 | #ifdef DEBUG_SIG | |
473 | printk("do_notify_resume flags:%x rip:%lx rsp:%lx caller:%lx pending:%lx\n", | |
474 | thread_info_flags, regs->rip, regs->rsp, __builtin_return_address(0),signal_pending(current)); | |
475 | #endif | |
476 | ||
477 | /* Pending single-step? */ | |
478 | if (thread_info_flags & _TIF_SINGLESTEP) { | |
479 | regs->eflags |= TF_MASK; | |
480 | clear_thread_flag(TIF_SINGLESTEP); | |
481 | } | |
482 | ||
483 | /* deal with pending signal delivery */ | |
484 | if (thread_info_flags & _TIF_SIGPENDING) | |
485 | do_signal(regs,oldset); | |
486 | } | |
487 | ||
488 | void signal_fault(struct pt_regs *regs, void __user *frame, char *where) | |
489 | { | |
490 | struct task_struct *me = current; | |
491 | if (exception_trace) | |
492 | printk("%s[%d] bad frame in %s frame:%p rip:%lx rsp:%lx orax:%lx\n", | |
493 | me->comm,me->pid,where,frame,regs->rip,regs->rsp,regs->orig_rax); | |
494 | ||
495 | force_sig(SIGSEGV, me); | |
496 | } |