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Diffstat (limited to 'arch/x86/kernel/signal_64.c')
-rw-r--r--arch/x86/kernel/signal_64.c495
1 files changed, 495 insertions, 0 deletions
diff --git a/arch/x86/kernel/signal_64.c b/arch/x86/kernel/signal_64.c
new file mode 100644
index 000000000000..739175b01e06
--- /dev/null
+++ b/arch/x86/kernel/signal_64.c
@@ -0,0 +1,495 @@
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
12#include <linux/sched.h>
13#include <linux/mm.h>
14#include <linux/smp.h>
15#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>
28#include <asm/ia32_unistd.h>
29#include <asm/mce.h>
30
31/* #define DEBUG_SIG 1 */
32
33#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
34
35int ia32_setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
36 sigset_t *set, struct pt_regs * regs);
37int ia32_setup_frame(int sig, struct k_sigaction *ka,
38 sigset_t *set, struct pt_regs * regs);
39
40asmlinkage long
41sys_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
52struct rt_sigframe
53{
54 char __user *pretcode;
55 struct ucontext uc;
56 struct siginfo info;
57};
58
59static int
60restore_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
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
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
116badframe:
117 return 1;
118}
119
120asmlinkage 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(&current->sighand->siglock);
136 current->blocked = set;
137 recalc_sigpending();
138 spin_unlock_irq(&current->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
152badframe:
153 signal_fault(regs,frame,"sigreturn");
154 return 0;
155}
156
157/*
158 * Set up a signal frame.
159 */
160
161static inline int
162setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs, unsigned long mask, struct task_struct *me)
163{
164 int err = 0;
165
166 err |= __put_user(regs->cs, &sc->cs);
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);
189 err |= __put_user(regs->eflags, &sc->eflags);
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
200static void __user *
201get_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. */
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
217static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
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 */
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
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. */
298 set_fs(USER_DS);
299
300 regs->eflags &= ~TF_MASK;
301 if (test_thread_flag(TIF_SINGLESTEP))
302 ptrace_notify(SIGTRAP);
303#ifdef DEBUG_SIG
304 printk("SIG deliver (%s:%d): sp=%p pc=%lx ra=%p\n",
305 current->comm, current->pid, frame, regs->rip, frame->pretcode);
306#endif
307
308 return 0;
309
310give_sigsegv:
311 force_sigsegv(sig, current);
312 return -EFAULT;
313}
314
315/*
316 * OK, we're invoking a handler
317 */
318
319static int
320handle_signal(unsigned long sig, siginfo_t *info, struct k_sigaction *ka,
321 sigset_t *oldset, struct pt_regs *regs)
322{
323 int ret;
324
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
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
365#ifdef CONFIG_IA32_EMULATION
366 if (test_thread_flag(TIF_IA32)) {
367 if (ka->sa.sa_flags & SA_SIGINFO)
368 ret = ia32_setup_rt_frame(sig, ka, info, oldset, regs);
369 else
370 ret = ia32_setup_frame(sig, ka, oldset, regs);
371 } else
372#endif
373 ret = setup_rt_frame(sig, ka, info, oldset, regs);
374
375 if (ret == 0) {
376 spin_lock_irq(&current->sighand->siglock);
377 sigorsets(&current->blocked,&current->blocked,&ka->sa.sa_mask);
378 if (!(ka->sa.sa_flags & SA_NODEFER))
379 sigaddset(&current->blocked,sig);
380 recalc_sigpending();
381 spin_unlock_irq(&current->sighand->siglock);
382 }
383
384 return ret;
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 */
392static void do_signal(struct pt_regs *regs)
393{
394 struct k_sigaction ka;
395 siginfo_t info;
396 int signr;
397 sigset_t *oldset;
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 */
405 if (!user_mode(regs))
406 return;
407
408 if (test_thread_flag(TIF_RESTORE_SIGMASK))
409 oldset = &current->saved_sigmask;
410 else
411 oldset = &current->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)
421 set_debugreg(current->thread.debugreg7, 7);
422
423 /* Whee! Actually deliver the signal. */
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;
432 }
433
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;
438 switch (res) {
439 case -ERESTARTNOHAND:
440 case -ERESTARTSYS:
441 case -ERESTARTNOINTR:
442 regs->rax = regs->orig_rax;
443 regs->rip -= 2;
444 break;
445 case -ERESTART_RESTARTBLOCK:
446 regs->rax = test_thread_flag(TIF_IA32) ?
447 __NR_ia32_restart_syscall :
448 __NR_restart_syscall;
449 regs->rip -= 2;
450 break;
451 }
452 }
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, &current->saved_sigmask, NULL);
459 }
460}
461
462void
463do_notify_resume(struct pt_regs *regs, void *unused, __u32 thread_info_flags)
464{
465#ifdef DEBUG_SIG
466 printk("do_notify_resume flags:%x rip:%lx rsp:%lx caller:%p pending:%x\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#ifdef CONFIG_X86_MCE
477 /* notify userspace of pending MCEs */
478 if (thread_info_flags & _TIF_MCE_NOTIFY)
479 mce_notify_user();
480#endif /* CONFIG_X86_MCE */
481
482 /* deal with pending signal delivery */
483 if (thread_info_flags & (_TIF_SIGPENDING|_TIF_RESTORE_SIGMASK))
484 do_signal(regs);
485}
486
487void signal_fault(struct pt_regs *regs, void __user *frame, char *where)
488{
489 struct task_struct *me = current;
490 if (show_unhandled_signals && printk_ratelimit())
491 printk("%s[%d] bad frame in %s frame:%p rip:%lx rsp:%lx orax:%lx\n",
492 me->comm,me->pid,where,frame,regs->rip,regs->rsp,regs->orig_rax);
493
494 force_sig(SIGSEGV, me);
495}
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