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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 | |
1da177e4 LT |
10 | */ |
11 | ||
12 | #include <linux/sched.h> | |
13 | #include <linux/mm.h> | |
14 | #include <linux/smp.h> | |
15 | #include <linux/smp_lock.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/stddef.h> | |
23 | #include <linux/personality.h> | |
24 | #include <linux/compiler.h> | |
25 | #include <asm/ucontext.h> | |
26 | #include <asm/uaccess.h> | |
27 | #include <asm/i387.h> | |
28 | #include <asm/proto.h> | |
c5924b7d | 29 | #include <asm/ia32_unistd.h> |
1da177e4 LT |
30 | |
31 | /* #define DEBUG_SIG 1 */ | |
32 | ||
33 | #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP))) | |
34 | ||
0928d6ef | 35 | int ia32_setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info, |
1da177e4 | 36 | sigset_t *set, struct pt_regs * regs); |
0928d6ef | 37 | int ia32_setup_frame(int sig, struct k_sigaction *ka, |
1da177e4 LT |
38 | sigset_t *set, struct pt_regs * regs); |
39 | ||
1da177e4 LT |
40 | asmlinkage long |
41 | sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss, | |
42 | struct pt_regs *regs) | |
43 | { | |
44 | return do_sigaltstack(uss, uoss, regs->rsp); | |
45 | } | |
46 | ||
47 | ||
48 | /* | |
49 | * Do a signal return; undo the signal stack. | |
50 | */ | |
51 | ||
52 | struct rt_sigframe | |
53 | { | |
993fb38b | 54 | char __user *pretcode; |
1da177e4 LT |
55 | struct ucontext uc; |
56 | struct siginfo info; | |
57 | }; | |
58 | ||
59 | static int | |
60 | restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc, unsigned long *prax) | |
61 | { | |
62 | unsigned int err = 0; | |
63 | ||
64 | /* Always make any pending restarted system calls return -EINTR */ | |
65 | current_thread_info()->restart_block.fn = do_no_restart_syscall; | |
66 | ||
67 | #define COPY(x) err |= __get_user(regs->x, &sc->x) | |
68 | ||
69 | COPY(rdi); COPY(rsi); COPY(rbp); COPY(rsp); COPY(rbx); | |
70 | COPY(rdx); COPY(rcx); COPY(rip); | |
71 | COPY(r8); | |
72 | COPY(r9); | |
73 | COPY(r10); | |
74 | COPY(r11); | |
75 | COPY(r12); | |
76 | COPY(r13); | |
77 | COPY(r14); | |
78 | COPY(r15); | |
79 | ||
e4e5d324 BF |
80 | /* Kernel saves and restores only the CS segment register on signals, |
81 | * which is the bare minimum needed to allow mixed 32/64-bit code. | |
82 | * App's signal handler can save/restore other segments if needed. */ | |
83 | { | |
84 | unsigned cs; | |
85 | err |= __get_user(cs, &sc->cs); | |
86 | regs->cs = cs | 3; /* Force into user mode */ | |
87 | } | |
88 | ||
1da177e4 LT |
89 | { |
90 | unsigned int tmpflags; | |
91 | err |= __get_user(tmpflags, &sc->eflags); | |
92 | regs->eflags = (regs->eflags & ~0x40DD5) | (tmpflags & 0x40DD5); | |
93 | regs->orig_rax = -1; /* disable syscall checks */ | |
94 | } | |
95 | ||
96 | { | |
97 | struct _fpstate __user * buf; | |
98 | err |= __get_user(buf, &sc->fpstate); | |
99 | ||
100 | if (buf) { | |
101 | if (!access_ok(VERIFY_READ, buf, sizeof(*buf))) | |
102 | goto badframe; | |
103 | err |= restore_i387(buf); | |
104 | } else { | |
105 | struct task_struct *me = current; | |
106 | if (used_math()) { | |
107 | clear_fpu(me); | |
108 | clear_used_math(); | |
109 | } | |
110 | } | |
111 | } | |
112 | ||
113 | err |= __get_user(*prax, &sc->rax); | |
114 | return err; | |
115 | ||
116 | badframe: | |
117 | return 1; | |
118 | } | |
119 | ||
120 | asmlinkage long sys_rt_sigreturn(struct pt_regs *regs) | |
121 | { | |
122 | struct rt_sigframe __user *frame; | |
123 | sigset_t set; | |
124 | unsigned long eax; | |
125 | ||
126 | frame = (struct rt_sigframe __user *)(regs->rsp - 8); | |
127 | if (!access_ok(VERIFY_READ, frame, sizeof(*frame))) { | |
128 | goto badframe; | |
129 | } | |
130 | if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set))) { | |
131 | goto badframe; | |
132 | } | |
133 | ||
134 | sigdelsetmask(&set, ~_BLOCKABLE); | |
135 | spin_lock_irq(¤t->sighand->siglock); | |
136 | current->blocked = set; | |
137 | recalc_sigpending(); | |
138 | spin_unlock_irq(¤t->sighand->siglock); | |
139 | ||
140 | if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &eax)) | |
141 | goto badframe; | |
142 | ||
143 | #ifdef DEBUG_SIG | |
144 | printk("%d sigreturn rip:%lx rsp:%lx frame:%p rax:%lx\n",current->pid,regs.rip,regs.rsp,frame,eax); | |
145 | #endif | |
146 | ||
147 | if (do_sigaltstack(&frame->uc.uc_stack, NULL, regs->rsp) == -EFAULT) | |
148 | goto badframe; | |
149 | ||
150 | return eax; | |
151 | ||
152 | badframe: | |
153 | signal_fault(regs,frame,"sigreturn"); | |
154 | return 0; | |
155 | } | |
156 | ||
157 | /* | |
158 | * Set up a signal frame. | |
159 | */ | |
160 | ||
161 | static inline int | |
162 | setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs, unsigned long mask, struct task_struct *me) | |
163 | { | |
164 | int err = 0; | |
1da177e4 | 165 | |
e4e5d324 | 166 | err |= __put_user(regs->cs, &sc->cs); |
1da177e4 LT |
167 | err |= __put_user(0, &sc->gs); |
168 | err |= __put_user(0, &sc->fs); | |
169 | ||
170 | err |= __put_user(regs->rdi, &sc->rdi); | |
171 | err |= __put_user(regs->rsi, &sc->rsi); | |
172 | err |= __put_user(regs->rbp, &sc->rbp); | |
173 | err |= __put_user(regs->rsp, &sc->rsp); | |
174 | err |= __put_user(regs->rbx, &sc->rbx); | |
175 | err |= __put_user(regs->rdx, &sc->rdx); | |
176 | err |= __put_user(regs->rcx, &sc->rcx); | |
177 | err |= __put_user(regs->rax, &sc->rax); | |
178 | err |= __put_user(regs->r8, &sc->r8); | |
179 | err |= __put_user(regs->r9, &sc->r9); | |
180 | err |= __put_user(regs->r10, &sc->r10); | |
181 | err |= __put_user(regs->r11, &sc->r11); | |
182 | err |= __put_user(regs->r12, &sc->r12); | |
183 | err |= __put_user(regs->r13, &sc->r13); | |
184 | err |= __put_user(regs->r14, &sc->r14); | |
185 | err |= __put_user(regs->r15, &sc->r15); | |
186 | err |= __put_user(me->thread.trap_no, &sc->trapno); | |
187 | err |= __put_user(me->thread.error_code, &sc->err); | |
188 | err |= __put_user(regs->rip, &sc->rip); | |
be61bff7 | 189 | err |= __put_user(regs->eflags, &sc->eflags); |
1da177e4 LT |
190 | err |= __put_user(mask, &sc->oldmask); |
191 | err |= __put_user(me->thread.cr2, &sc->cr2); | |
192 | ||
193 | return err; | |
194 | } | |
195 | ||
196 | /* | |
197 | * Determine which stack to use.. | |
198 | */ | |
199 | ||
200 | static void __user * | |
201 | get_stack(struct k_sigaction *ka, struct pt_regs *regs, unsigned long size) | |
202 | { | |
203 | unsigned long rsp; | |
204 | ||
205 | /* Default to using normal stack - redzone*/ | |
206 | rsp = regs->rsp - 128; | |
207 | ||
208 | /* This is the X/Open sanctioned signal stack switching. */ | |
1da177e4 LT |
209 | if (ka->sa.sa_flags & SA_ONSTACK) { |
210 | if (sas_ss_flags(rsp) == 0) | |
211 | rsp = current->sas_ss_sp + current->sas_ss_size; | |
212 | } | |
213 | ||
214 | return (void __user *)round_down(rsp - size, 16); | |
215 | } | |
216 | ||
0928d6ef | 217 | static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info, |
1da177e4 LT |
218 | sigset_t *set, struct pt_regs * regs) |
219 | { | |
220 | struct rt_sigframe __user *frame; | |
221 | struct _fpstate __user *fp = NULL; | |
222 | int err = 0; | |
223 | struct task_struct *me = current; | |
224 | ||
225 | if (used_math()) { | |
226 | fp = get_stack(ka, regs, sizeof(struct _fpstate)); | |
227 | frame = (void __user *)round_down( | |
228 | (unsigned long)fp - sizeof(struct rt_sigframe), 16) - 8; | |
229 | ||
230 | if (!access_ok(VERIFY_WRITE, fp, sizeof(struct _fpstate))) | |
231 | goto give_sigsegv; | |
232 | ||
233 | if (save_i387(fp) < 0) | |
234 | err |= -1; | |
235 | } else | |
236 | frame = get_stack(ka, regs, sizeof(struct rt_sigframe)) - 8; | |
237 | ||
238 | if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) | |
239 | goto give_sigsegv; | |
240 | ||
241 | if (ka->sa.sa_flags & SA_SIGINFO) { | |
242 | err |= copy_siginfo_to_user(&frame->info, info); | |
243 | if (err) | |
244 | goto give_sigsegv; | |
245 | } | |
246 | ||
247 | /* Create the ucontext. */ | |
248 | err |= __put_user(0, &frame->uc.uc_flags); | |
249 | err |= __put_user(0, &frame->uc.uc_link); | |
250 | err |= __put_user(me->sas_ss_sp, &frame->uc.uc_stack.ss_sp); | |
251 | err |= __put_user(sas_ss_flags(regs->rsp), | |
252 | &frame->uc.uc_stack.ss_flags); | |
253 | err |= __put_user(me->sas_ss_size, &frame->uc.uc_stack.ss_size); | |
254 | err |= setup_sigcontext(&frame->uc.uc_mcontext, regs, set->sig[0], me); | |
255 | err |= __put_user(fp, &frame->uc.uc_mcontext.fpstate); | |
256 | if (sizeof(*set) == 16) { | |
257 | __put_user(set->sig[0], &frame->uc.uc_sigmask.sig[0]); | |
258 | __put_user(set->sig[1], &frame->uc.uc_sigmask.sig[1]); | |
259 | } else | |
260 | err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)); | |
261 | ||
262 | /* Set up to return from userspace. If provided, use a stub | |
263 | already in userspace. */ | |
264 | /* x86-64 should always use SA_RESTORER. */ | |
265 | if (ka->sa.sa_flags & SA_RESTORER) { | |
266 | err |= __put_user(ka->sa.sa_restorer, &frame->pretcode); | |
267 | } else { | |
268 | /* could use a vstub here */ | |
269 | goto give_sigsegv; | |
270 | } | |
271 | ||
272 | if (err) | |
273 | goto give_sigsegv; | |
274 | ||
275 | #ifdef DEBUG_SIG | |
276 | printk("%d old rip %lx old rsp %lx old rax %lx\n", current->pid,regs->rip,regs->rsp,regs->rax); | |
277 | #endif | |
278 | ||
279 | /* Set up registers for signal handler */ | |
1da177e4 LT |
280 | regs->rdi = sig; |
281 | /* In case the signal handler was declared without prototypes */ | |
282 | regs->rax = 0; | |
283 | ||
284 | /* This also works for non SA_SIGINFO handlers because they expect the | |
285 | next argument after the signal number on the stack. */ | |
286 | regs->rsi = (unsigned long)&frame->info; | |
287 | regs->rdx = (unsigned long)&frame->uc; | |
288 | regs->rip = (unsigned long) ka->sa.sa_handler; | |
289 | ||
290 | regs->rsp = (unsigned long)frame; | |
291 | ||
e4e5d324 BF |
292 | /* Set up the CS register to run signal handlers in 64-bit mode, |
293 | even if the handler happens to be interrupting 32-bit code. */ | |
294 | regs->cs = __USER_CS; | |
295 | ||
296 | /* This, by contrast, has nothing to do with segment registers - | |
297 | see include/asm-x86_64/uaccess.h for details. */ | |
1da177e4 | 298 | set_fs(USER_DS); |
e4e5d324 | 299 | |
be61bff7 AK |
300 | regs->eflags &= ~TF_MASK; |
301 | if (test_thread_flag(TIF_SINGLESTEP)) | |
302 | ptrace_notify(SIGTRAP); | |
1da177e4 LT |
303 | #ifdef DEBUG_SIG |
304 | printk("SIG deliver (%s:%d): sp=%p pc=%p ra=%p\n", | |
305 | current->comm, current->pid, frame, regs->rip, frame->pretcode); | |
306 | #endif | |
307 | ||
1d001df1 | 308 | return 0; |
1da177e4 LT |
309 | |
310 | give_sigsegv: | |
311 | force_sigsegv(sig, current); | |
1d001df1 | 312 | return -EFAULT; |
1da177e4 LT |
313 | } |
314 | ||
315 | /* | |
316 | * OK, we're invoking a handler | |
317 | */ | |
318 | ||
0928d6ef | 319 | static int |
1da177e4 LT |
320 | handle_signal(unsigned long sig, siginfo_t *info, struct k_sigaction *ka, |
321 | sigset_t *oldset, struct pt_regs *regs) | |
322 | { | |
0928d6ef RM |
323 | int ret; |
324 | ||
1da177e4 LT |
325 | #ifdef DEBUG_SIG |
326 | printk("handle_signal pid:%d sig:%lu rip:%lx rsp:%lx regs=%p\n", | |
327 | current->pid, sig, | |
328 | regs->rip, regs->rsp, regs); | |
329 | #endif | |
330 | ||
331 | /* Are we from a system call? */ | |
332 | if ((long)regs->orig_rax >= 0) { | |
333 | /* If so, check system call restarting.. */ | |
334 | switch (regs->rax) { | |
335 | case -ERESTART_RESTARTBLOCK: | |
336 | case -ERESTARTNOHAND: | |
337 | regs->rax = -EINTR; | |
338 | break; | |
339 | ||
340 | case -ERESTARTSYS: | |
341 | if (!(ka->sa.sa_flags & SA_RESTART)) { | |
342 | regs->rax = -EINTR; | |
343 | break; | |
344 | } | |
345 | /* fallthrough */ | |
346 | case -ERESTARTNOINTR: | |
347 | regs->rax = regs->orig_rax; | |
348 | regs->rip -= 2; | |
349 | break; | |
350 | } | |
351 | } | |
352 | ||
d61915da AK |
353 | /* |
354 | * If TF is set due to a debugger (PT_DTRACE), clear the TF | |
355 | * flag so that register information in the sigcontext is | |
356 | * correct. | |
357 | */ | |
358 | if (unlikely(regs->eflags & TF_MASK)) { | |
359 | if (likely(current->ptrace & PT_DTRACE)) { | |
360 | current->ptrace &= ~PT_DTRACE; | |
361 | regs->eflags &= ~TF_MASK; | |
362 | } | |
363 | } | |
364 | ||
1da177e4 LT |
365 | #ifdef CONFIG_IA32_EMULATION |
366 | if (test_thread_flag(TIF_IA32)) { | |
367 | if (ka->sa.sa_flags & SA_SIGINFO) | |
0928d6ef | 368 | ret = ia32_setup_rt_frame(sig, ka, info, oldset, regs); |
1da177e4 | 369 | else |
0928d6ef | 370 | ret = ia32_setup_frame(sig, ka, oldset, regs); |
1da177e4 LT |
371 | } else |
372 | #endif | |
0928d6ef | 373 | ret = setup_rt_frame(sig, ka, info, oldset, regs); |
1da177e4 | 374 | |
1d001df1 | 375 | if (ret == 0) { |
1da177e4 LT |
376 | spin_lock_irq(¤t->sighand->siglock); |
377 | sigorsets(¤t->blocked,¤t->blocked,&ka->sa.sa_mask); | |
69be8f18 SR |
378 | if (!(ka->sa.sa_flags & SA_NODEFER)) |
379 | sigaddset(¤t->blocked,sig); | |
1da177e4 LT |
380 | recalc_sigpending(); |
381 | spin_unlock_irq(¤t->sighand->siglock); | |
382 | } | |
0928d6ef RM |
383 | |
384 | return ret; | |
1da177e4 LT |
385 | } |
386 | ||
387 | /* | |
388 | * Note that 'init' is a special process: it doesn't get signals it doesn't | |
389 | * want to handle. Thus you cannot kill init even with a SIGKILL even by | |
390 | * mistake. | |
391 | */ | |
1d001df1 | 392 | static void do_signal(struct pt_regs *regs) |
1da177e4 LT |
393 | { |
394 | struct k_sigaction ka; | |
395 | siginfo_t info; | |
396 | int signr; | |
1d001df1 | 397 | sigset_t *oldset; |
1da177e4 LT |
398 | |
399 | /* | |
400 | * We want the common case to go fast, which | |
401 | * is why we may in certain cases get here from | |
402 | * kernel mode. Just return without doing anything | |
403 | * if so. | |
404 | */ | |
76381fee | 405 | if (!user_mode(regs)) |
1d001df1 | 406 | return; |
1da177e4 | 407 | |
1d001df1 AK |
408 | if (test_thread_flag(TIF_RESTORE_SIGMASK)) |
409 | oldset = ¤t->saved_sigmask; | |
410 | else | |
1da177e4 LT |
411 | oldset = ¤t->blocked; |
412 | ||
413 | signr = get_signal_to_deliver(&info, &ka, regs, NULL); | |
414 | if (signr > 0) { | |
415 | /* Reenable any watchpoints before delivering the | |
416 | * signal to user space. The processor register will | |
417 | * have been cleared if the watchpoint triggered | |
418 | * inside the kernel. | |
419 | */ | |
420 | if (current->thread.debugreg7) | |
e9129e56 | 421 | set_debugreg(current->thread.debugreg7, 7); |
1da177e4 LT |
422 | |
423 | /* Whee! Actually deliver the signal. */ | |
1d001df1 AK |
424 | if (handle_signal(signr, &info, &ka, oldset, regs) == 0) { |
425 | /* a signal was successfully delivered; the saved | |
426 | * sigmask will have been stored in the signal frame, | |
427 | * and will be restored by sigreturn, so we can simply | |
428 | * clear the TIF_RESTORE_SIGMASK flag */ | |
429 | clear_thread_flag(TIF_RESTORE_SIGMASK); | |
430 | } | |
431 | return; | |
1da177e4 LT |
432 | } |
433 | ||
1da177e4 LT |
434 | /* Did we come from a system call? */ |
435 | if ((long)regs->orig_rax >= 0) { | |
436 | /* Restart the system call - no handlers present */ | |
437 | long res = regs->rax; | |
1d001df1 AK |
438 | switch (res) { |
439 | case -ERESTARTNOHAND: | |
440 | case -ERESTARTSYS: | |
441 | case -ERESTARTNOINTR: | |
1da177e4 LT |
442 | regs->rax = regs->orig_rax; |
443 | regs->rip -= 2; | |
1d001df1 AK |
444 | break; |
445 | case -ERESTART_RESTARTBLOCK: | |
607a1685 AK |
446 | regs->rax = test_thread_flag(TIF_IA32) ? |
447 | __NR_ia32_restart_syscall : | |
448 | __NR_restart_syscall; | |
1da177e4 | 449 | regs->rip -= 2; |
1d001df1 | 450 | break; |
1da177e4 LT |
451 | } |
452 | } | |
1d001df1 AK |
453 | |
454 | /* if there's no signal to deliver, we just put the saved sigmask | |
455 | back. */ | |
456 | if (test_thread_flag(TIF_RESTORE_SIGMASK)) { | |
457 | clear_thread_flag(TIF_RESTORE_SIGMASK); | |
458 | sigprocmask(SIG_SETMASK, ¤t->saved_sigmask, NULL); | |
459 | } | |
1da177e4 LT |
460 | } |
461 | ||
1d001df1 AK |
462 | void |
463 | do_notify_resume(struct pt_regs *regs, void *unused, __u32 thread_info_flags) | |
1da177e4 LT |
464 | { |
465 | #ifdef DEBUG_SIG | |
466 | printk("do_notify_resume flags:%x rip:%lx rsp:%lx caller:%lx pending:%lx\n", | |
467 | thread_info_flags, regs->rip, regs->rsp, __builtin_return_address(0),signal_pending(current)); | |
468 | #endif | |
469 | ||
470 | /* Pending single-step? */ | |
471 | if (thread_info_flags & _TIF_SINGLESTEP) { | |
472 | regs->eflags |= TF_MASK; | |
473 | clear_thread_flag(TIF_SINGLESTEP); | |
474 | } | |
475 | ||
476 | /* deal with pending signal delivery */ | |
1d001df1 AK |
477 | if (thread_info_flags & (_TIF_SIGPENDING|_TIF_RESTORE_SIGMASK)) |
478 | do_signal(regs); | |
1da177e4 LT |
479 | } |
480 | ||
481 | void signal_fault(struct pt_regs *regs, void __user *frame, char *where) | |
482 | { | |
483 | struct task_struct *me = current; | |
484 | if (exception_trace) | |
485 | printk("%s[%d] bad frame in %s frame:%p rip:%lx rsp:%lx orax:%lx\n", | |
486 | me->comm,me->pid,where,frame,regs->rip,regs->rsp,regs->orig_rax); | |
487 | ||
488 | force_sig(SIGSEGV, me); | |
489 | } |