blob: 290f5d8037cd804e6fedbc9e1b7b602e5db10b58 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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
Linus Torvalds1da177e2005-04-16 15:20:36 -070010 */
11
12#include <linux/sched.h>
13#include <linux/mm.h>
14#include <linux/smp.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070015#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/personality.h>
23#include <linux/compiler.h>
24#include <asm/ucontext.h>
25#include <asm/uaccess.h>
26#include <asm/i387.h>
27#include <asm/proto.h>
Oliver Korpillac5924b72005-05-27 12:52:55 -070028#include <asm/ia32_unistd.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070029
30/* #define DEBUG_SIG 1 */
31
32#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
33
Roland McGrath0928d6e2005-06-23 00:08:37 -070034int ia32_setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
Linus Torvalds1da177e2005-04-16 15:20:36 -070035 sigset_t *set, struct pt_regs * regs);
Roland McGrath0928d6e2005-06-23 00:08:37 -070036int ia32_setup_frame(int sig, struct k_sigaction *ka,
Linus Torvalds1da177e2005-04-16 15:20:36 -070037 sigset_t *set, struct pt_regs * regs);
38
39asmlinkage long
Linus Torvalds1da177e2005-04-16 15:20:36 -070040sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss,
41 struct pt_regs *regs)
42{
43 return do_sigaltstack(uss, uoss, regs->rsp);
44}
45
46
47/*
48 * Do a signal return; undo the signal stack.
49 */
50
51struct rt_sigframe
52{
Al Viro993fb382005-04-26 07:43:42 -070053 char __user *pretcode;
Linus Torvalds1da177e2005-04-16 15:20:36 -070054 struct ucontext uc;
55 struct siginfo info;
56};
57
58static int
59restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc, unsigned long *prax)
60{
61 unsigned int err = 0;
62
63 /* Always make any pending restarted system calls return -EINTR */
64 current_thread_info()->restart_block.fn = do_no_restart_syscall;
65
66#define COPY(x) err |= __get_user(regs->x, &sc->x)
67
68 COPY(rdi); COPY(rsi); COPY(rbp); COPY(rsp); COPY(rbx);
69 COPY(rdx); COPY(rcx); COPY(rip);
70 COPY(r8);
71 COPY(r9);
72 COPY(r10);
73 COPY(r11);
74 COPY(r12);
75 COPY(r13);
76 COPY(r14);
77 COPY(r15);
78
Bryan Forde4e5d3242005-11-05 17:25:54 +010079 /* Kernel saves and restores only the CS segment register on signals,
80 * which is the bare minimum needed to allow mixed 32/64-bit code.
81 * App's signal handler can save/restore other segments if needed. */
82 {
83 unsigned cs;
84 err |= __get_user(cs, &sc->cs);
85 regs->cs = cs | 3; /* Force into user mode */
86 }
87
Linus Torvalds1da177e2005-04-16 15:20:36 -070088 {
89 unsigned int tmpflags;
90 err |= __get_user(tmpflags, &sc->eflags);
91 regs->eflags = (regs->eflags & ~0x40DD5) | (tmpflags & 0x40DD5);
92 regs->orig_rax = -1; /* disable syscall checks */
93 }
94
95 {
96 struct _fpstate __user * buf;
97 err |= __get_user(buf, &sc->fpstate);
98
99 if (buf) {
100 if (!access_ok(VERIFY_READ, buf, sizeof(*buf)))
101 goto badframe;
102 err |= restore_i387(buf);
103 } else {
104 struct task_struct *me = current;
105 if (used_math()) {
106 clear_fpu(me);
107 clear_used_math();
108 }
109 }
110 }
111
112 err |= __get_user(*prax, &sc->rax);
113 return err;
114
115badframe:
116 return 1;
117}
118
119asmlinkage long sys_rt_sigreturn(struct pt_regs *regs)
120{
121 struct rt_sigframe __user *frame;
122 sigset_t set;
123 unsigned long eax;
124
125 frame = (struct rt_sigframe __user *)(regs->rsp - 8);
126 if (!access_ok(VERIFY_READ, frame, sizeof(*frame))) {
127 goto badframe;
128 }
129 if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set))) {
130 goto badframe;
131 }
132
133 sigdelsetmask(&set, ~_BLOCKABLE);
134 spin_lock_irq(&current->sighand->siglock);
135 current->blocked = set;
136 recalc_sigpending();
137 spin_unlock_irq(&current->sighand->siglock);
138
139 if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &eax))
140 goto badframe;
141
142#ifdef DEBUG_SIG
Glauber de Oliveira Costa1c3d99c2007-05-02 19:27:13 +0200143 printk("%d sigreturn rip:%lx rsp:%lx frame:%p rax:%lx\n",current->pid,regs->rip,regs->rsp,frame,eax);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700144#endif
145
146 if (do_sigaltstack(&frame->uc.uc_stack, NULL, regs->rsp) == -EFAULT)
147 goto badframe;
148
149 return eax;
150
151badframe:
152 signal_fault(regs,frame,"sigreturn");
153 return 0;
154}
155
156/*
157 * Set up a signal frame.
158 */
159
160static inline int
161setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs, unsigned long mask, struct task_struct *me)
162{
163 int err = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700164
Bryan Forde4e5d3242005-11-05 17:25:54 +0100165 err |= __put_user(regs->cs, &sc->cs);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700166 err |= __put_user(0, &sc->gs);
167 err |= __put_user(0, &sc->fs);
168
169 err |= __put_user(regs->rdi, &sc->rdi);
170 err |= __put_user(regs->rsi, &sc->rsi);
171 err |= __put_user(regs->rbp, &sc->rbp);
172 err |= __put_user(regs->rsp, &sc->rsp);
173 err |= __put_user(regs->rbx, &sc->rbx);
174 err |= __put_user(regs->rdx, &sc->rdx);
175 err |= __put_user(regs->rcx, &sc->rcx);
176 err |= __put_user(regs->rax, &sc->rax);
177 err |= __put_user(regs->r8, &sc->r8);
178 err |= __put_user(regs->r9, &sc->r9);
179 err |= __put_user(regs->r10, &sc->r10);
180 err |= __put_user(regs->r11, &sc->r11);
181 err |= __put_user(regs->r12, &sc->r12);
182 err |= __put_user(regs->r13, &sc->r13);
183 err |= __put_user(regs->r14, &sc->r14);
184 err |= __put_user(regs->r15, &sc->r15);
185 err |= __put_user(me->thread.trap_no, &sc->trapno);
186 err |= __put_user(me->thread.error_code, &sc->err);
187 err |= __put_user(regs->rip, &sc->rip);
Andi Kleenbe61bff2005-04-16 15:24:57 -0700188 err |= __put_user(regs->eflags, &sc->eflags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700189 err |= __put_user(mask, &sc->oldmask);
190 err |= __put_user(me->thread.cr2, &sc->cr2);
191
192 return err;
193}
194
195/*
196 * Determine which stack to use..
197 */
198
199static void __user *
200get_stack(struct k_sigaction *ka, struct pt_regs *regs, unsigned long size)
201{
202 unsigned long rsp;
203
204 /* Default to using normal stack - redzone*/
205 rsp = regs->rsp - 128;
206
207 /* This is the X/Open sanctioned signal stack switching. */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700208 if (ka->sa.sa_flags & SA_ONSTACK) {
209 if (sas_ss_flags(rsp) == 0)
210 rsp = current->sas_ss_sp + current->sas_ss_size;
211 }
212
213 return (void __user *)round_down(rsp - size, 16);
214}
215
Roland McGrath0928d6e2005-06-23 00:08:37 -0700216static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700217 sigset_t *set, struct pt_regs * regs)
218{
219 struct rt_sigframe __user *frame;
220 struct _fpstate __user *fp = NULL;
221 int err = 0;
222 struct task_struct *me = current;
223
224 if (used_math()) {
225 fp = get_stack(ka, regs, sizeof(struct _fpstate));
226 frame = (void __user *)round_down(
227 (unsigned long)fp - sizeof(struct rt_sigframe), 16) - 8;
228
229 if (!access_ok(VERIFY_WRITE, fp, sizeof(struct _fpstate)))
230 goto give_sigsegv;
231
232 if (save_i387(fp) < 0)
233 err |= -1;
234 } else
235 frame = get_stack(ka, regs, sizeof(struct rt_sigframe)) - 8;
236
237 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
238 goto give_sigsegv;
239
240 if (ka->sa.sa_flags & SA_SIGINFO) {
241 err |= copy_siginfo_to_user(&frame->info, info);
242 if (err)
243 goto give_sigsegv;
244 }
245
246 /* Create the ucontext. */
247 err |= __put_user(0, &frame->uc.uc_flags);
248 err |= __put_user(0, &frame->uc.uc_link);
249 err |= __put_user(me->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
250 err |= __put_user(sas_ss_flags(regs->rsp),
251 &frame->uc.uc_stack.ss_flags);
252 err |= __put_user(me->sas_ss_size, &frame->uc.uc_stack.ss_size);
253 err |= setup_sigcontext(&frame->uc.uc_mcontext, regs, set->sig[0], me);
254 err |= __put_user(fp, &frame->uc.uc_mcontext.fpstate);
255 if (sizeof(*set) == 16) {
256 __put_user(set->sig[0], &frame->uc.uc_sigmask.sig[0]);
257 __put_user(set->sig[1], &frame->uc.uc_sigmask.sig[1]);
258 } else
259 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
260
261 /* Set up to return from userspace. If provided, use a stub
262 already in userspace. */
263 /* x86-64 should always use SA_RESTORER. */
264 if (ka->sa.sa_flags & SA_RESTORER) {
265 err |= __put_user(ka->sa.sa_restorer, &frame->pretcode);
266 } else {
267 /* could use a vstub here */
268 goto give_sigsegv;
269 }
270
271 if (err)
272 goto give_sigsegv;
273
274#ifdef DEBUG_SIG
275 printk("%d old rip %lx old rsp %lx old rax %lx\n", current->pid,regs->rip,regs->rsp,regs->rax);
276#endif
277
278 /* Set up registers for signal handler */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700279 regs->rdi = sig;
280 /* In case the signal handler was declared without prototypes */
281 regs->rax = 0;
282
283 /* This also works for non SA_SIGINFO handlers because they expect the
284 next argument after the signal number on the stack. */
285 regs->rsi = (unsigned long)&frame->info;
286 regs->rdx = (unsigned long)&frame->uc;
287 regs->rip = (unsigned long) ka->sa.sa_handler;
288
289 regs->rsp = (unsigned long)frame;
290
Bryan Forde4e5d3242005-11-05 17:25:54 +0100291 /* Set up the CS register to run signal handlers in 64-bit mode,
292 even if the handler happens to be interrupting 32-bit code. */
293 regs->cs = __USER_CS;
294
295 /* This, by contrast, has nothing to do with segment registers -
296 see include/asm-x86_64/uaccess.h for details. */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700297 set_fs(USER_DS);
Bryan Forde4e5d3242005-11-05 17:25:54 +0100298
Andi Kleenbe61bff2005-04-16 15:24:57 -0700299 regs->eflags &= ~TF_MASK;
300 if (test_thread_flag(TIF_SINGLESTEP))
301 ptrace_notify(SIGTRAP);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700302#ifdef DEBUG_SIG
Glauber de Oliveira Costa1c3d99c2007-05-02 19:27:13 +0200303 printk("SIG deliver (%s:%d): sp=%p pc=%lx ra=%p\n",
Linus Torvalds1da177e2005-04-16 15:20:36 -0700304 current->comm, current->pid, frame, regs->rip, frame->pretcode);
305#endif
306
Andi Kleen1d001df2006-09-26 10:52:26 +0200307 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700308
309give_sigsegv:
310 force_sigsegv(sig, current);
Andi Kleen1d001df2006-09-26 10:52:26 +0200311 return -EFAULT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700312}
313
314/*
315 * OK, we're invoking a handler
316 */
317
Roland McGrath0928d6e2005-06-23 00:08:37 -0700318static int
Linus Torvalds1da177e2005-04-16 15:20:36 -0700319handle_signal(unsigned long sig, siginfo_t *info, struct k_sigaction *ka,
320 sigset_t *oldset, struct pt_regs *regs)
321{
Roland McGrath0928d6e2005-06-23 00:08:37 -0700322 int ret;
323
Linus Torvalds1da177e2005-04-16 15:20:36 -0700324#ifdef DEBUG_SIG
325 printk("handle_signal pid:%d sig:%lu rip:%lx rsp:%lx regs=%p\n",
326 current->pid, sig,
327 regs->rip, regs->rsp, regs);
328#endif
329
330 /* Are we from a system call? */
331 if ((long)regs->orig_rax >= 0) {
332 /* If so, check system call restarting.. */
333 switch (regs->rax) {
334 case -ERESTART_RESTARTBLOCK:
335 case -ERESTARTNOHAND:
336 regs->rax = -EINTR;
337 break;
338
339 case -ERESTARTSYS:
340 if (!(ka->sa.sa_flags & SA_RESTART)) {
341 regs->rax = -EINTR;
342 break;
343 }
344 /* fallthrough */
345 case -ERESTARTNOINTR:
346 regs->rax = regs->orig_rax;
347 regs->rip -= 2;
348 break;
349 }
350 }
351
Andi Kleend61915d2005-04-16 15:25:00 -0700352 /*
353 * If TF is set due to a debugger (PT_DTRACE), clear the TF
354 * flag so that register information in the sigcontext is
355 * correct.
356 */
357 if (unlikely(regs->eflags & TF_MASK)) {
358 if (likely(current->ptrace & PT_DTRACE)) {
359 current->ptrace &= ~PT_DTRACE;
360 regs->eflags &= ~TF_MASK;
361 }
362 }
363
Linus Torvalds1da177e2005-04-16 15:20:36 -0700364#ifdef CONFIG_IA32_EMULATION
365 if (test_thread_flag(TIF_IA32)) {
366 if (ka->sa.sa_flags & SA_SIGINFO)
Roland McGrath0928d6e2005-06-23 00:08:37 -0700367 ret = ia32_setup_rt_frame(sig, ka, info, oldset, regs);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700368 else
Roland McGrath0928d6e2005-06-23 00:08:37 -0700369 ret = ia32_setup_frame(sig, ka, oldset, regs);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700370 } else
371#endif
Roland McGrath0928d6e2005-06-23 00:08:37 -0700372 ret = setup_rt_frame(sig, ka, info, oldset, regs);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700373
Andi Kleen1d001df2006-09-26 10:52:26 +0200374 if (ret == 0) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700375 spin_lock_irq(&current->sighand->siglock);
376 sigorsets(&current->blocked,&current->blocked,&ka->sa.sa_mask);
Steven Rostedt69be8f12005-08-29 11:44:09 -0400377 if (!(ka->sa.sa_flags & SA_NODEFER))
378 sigaddset(&current->blocked,sig);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700379 recalc_sigpending();
380 spin_unlock_irq(&current->sighand->siglock);
381 }
Roland McGrath0928d6e2005-06-23 00:08:37 -0700382
383 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700384}
385
386/*
387 * Note that 'init' is a special process: it doesn't get signals it doesn't
388 * want to handle. Thus you cannot kill init even with a SIGKILL even by
389 * mistake.
390 */
Andi Kleen1d001df2006-09-26 10:52:26 +0200391static void do_signal(struct pt_regs *regs)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700392{
393 struct k_sigaction ka;
394 siginfo_t info;
395 int signr;
Andi Kleen1d001df2006-09-26 10:52:26 +0200396 sigset_t *oldset;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700397
398 /*
399 * We want the common case to go fast, which
400 * is why we may in certain cases get here from
401 * kernel mode. Just return without doing anything
402 * if so.
403 */
Vincent Hanquez76381fe2005-06-23 00:08:46 -0700404 if (!user_mode(regs))
Andi Kleen1d001df2006-09-26 10:52:26 +0200405 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700406
Andi Kleen1d001df2006-09-26 10:52:26 +0200407 if (test_thread_flag(TIF_RESTORE_SIGMASK))
408 oldset = &current->saved_sigmask;
409 else
Linus Torvalds1da177e2005-04-16 15:20:36 -0700410 oldset = &current->blocked;
411
412 signr = get_signal_to_deliver(&info, &ka, regs, NULL);
413 if (signr > 0) {
414 /* Reenable any watchpoints before delivering the
415 * signal to user space. The processor register will
416 * have been cleared if the watchpoint triggered
417 * inside the kernel.
418 */
419 if (current->thread.debugreg7)
Vincent Hanqueze9129e52005-06-23 00:08:46 -0700420 set_debugreg(current->thread.debugreg7, 7);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700421
422 /* Whee! Actually deliver the signal. */
Andi Kleen1d001df2006-09-26 10:52:26 +0200423 if (handle_signal(signr, &info, &ka, oldset, regs) == 0) {
424 /* a signal was successfully delivered; the saved
425 * sigmask will have been stored in the signal frame,
426 * and will be restored by sigreturn, so we can simply
427 * clear the TIF_RESTORE_SIGMASK flag */
428 clear_thread_flag(TIF_RESTORE_SIGMASK);
429 }
430 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700431 }
432
Linus Torvalds1da177e2005-04-16 15:20:36 -0700433 /* Did we come from a system call? */
434 if ((long)regs->orig_rax >= 0) {
435 /* Restart the system call - no handlers present */
436 long res = regs->rax;
Andi Kleen1d001df2006-09-26 10:52:26 +0200437 switch (res) {
438 case -ERESTARTNOHAND:
439 case -ERESTARTSYS:
440 case -ERESTARTNOINTR:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700441 regs->rax = regs->orig_rax;
442 regs->rip -= 2;
Andi Kleen1d001df2006-09-26 10:52:26 +0200443 break;
444 case -ERESTART_RESTARTBLOCK:
Andi Kleen607a1682005-05-20 14:27:58 -0700445 regs->rax = test_thread_flag(TIF_IA32) ?
446 __NR_ia32_restart_syscall :
447 __NR_restart_syscall;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700448 regs->rip -= 2;
Andi Kleen1d001df2006-09-26 10:52:26 +0200449 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700450 }
451 }
Andi Kleen1d001df2006-09-26 10:52:26 +0200452
453 /* if there's no signal to deliver, we just put the saved sigmask
454 back. */
455 if (test_thread_flag(TIF_RESTORE_SIGMASK)) {
456 clear_thread_flag(TIF_RESTORE_SIGMASK);
457 sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
458 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700459}
460
Andi Kleen1d001df2006-09-26 10:52:26 +0200461void
462do_notify_resume(struct pt_regs *regs, void *unused, __u32 thread_info_flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700463{
464#ifdef DEBUG_SIG
Glauber de Oliveira Costa1c3d99c2007-05-02 19:27:13 +0200465 printk("do_notify_resume flags:%x rip:%lx rsp:%lx caller:%p pending:%x\n",
Linus Torvalds1da177e2005-04-16 15:20:36 -0700466 thread_info_flags, regs->rip, regs->rsp, __builtin_return_address(0),signal_pending(current));
467#endif
468
469 /* Pending single-step? */
470 if (thread_info_flags & _TIF_SINGLESTEP) {
471 regs->eflags |= TF_MASK;
472 clear_thread_flag(TIF_SINGLESTEP);
473 }
474
475 /* deal with pending signal delivery */
Andi Kleen1d001df2006-09-26 10:52:26 +0200476 if (thread_info_flags & (_TIF_SIGPENDING|_TIF_RESTORE_SIGMASK))
477 do_signal(regs);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700478}
479
480void signal_fault(struct pt_regs *regs, void __user *frame, char *where)
481{
482 struct task_struct *me = current;
483 if (exception_trace)
484 printk("%s[%d] bad frame in %s frame:%p rip:%lx rsp:%lx orax:%lx\n",
485 me->comm,me->pid,where,frame,regs->rip,regs->rsp,regs->orig_rax);
486
487 force_sig(SIGSEGV, me);
488}