2 * Copyright (C) 1991, 1992 Linus Torvalds
3 * Copyright 2010 Tilera Corporation. All Rights Reserved.
5 * This program is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU General Public License
7 * as published by the Free Software Foundation, version 2.
9 * This program is distributed in the hope that it will be useful, but
10 * WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
12 * NON INFRINGEMENT. See the GNU General Public License for
16 #include <linux/sched.h>
18 #include <linux/smp.h>
19 #include <linux/kernel.h>
20 #include <linux/signal.h>
21 #include <linux/errno.h>
22 #include <linux/wait.h>
23 #include <linux/unistd.h>
24 #include <linux/stddef.h>
25 #include <linux/personality.h>
26 #include <linux/suspend.h>
27 #include <linux/ptrace.h>
28 #include <linux/elf.h>
29 #include <linux/compat.h>
30 #include <linux/syscalls.h>
31 #include <linux/uaccess.h>
32 #include <asm/processor.h>
33 #include <asm/ucontext.h>
34 #include <asm/sigframe.h>
35 #include <asm/syscalls.h>
36 #include <arch/interrupts.h>
40 #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
42 SYSCALL_DEFINE3(sigaltstack, const stack_t __user *, uss,
43 stack_t __user *, uoss, struct pt_regs *, regs)
45 return do_sigaltstack(uss, uoss, regs->sp);
50 * Do a signal return; undo the signal stack.
53 int restore_sigcontext(struct pt_regs *regs,
54 struct sigcontext __user *sc)
59 /* Always make any pending restarted system calls return -EINTR */
60 current_thread_info()->restart_block.fn = do_no_restart_syscall;
63 * Enforce that sigcontext is like pt_regs, and doesn't mess
64 * up our stack alignment rules.
66 BUILD_BUG_ON(sizeof(struct sigcontext) != sizeof(struct pt_regs));
67 BUILD_BUG_ON(sizeof(struct sigcontext) % 8 != 0);
69 for (i = 0; i < sizeof(struct pt_regs)/sizeof(long); ++i)
70 err |= __get_user(regs->regs[i], &sc->gregs[i]);
72 /* Ensure that the PL is always set to USER_PL. */
73 regs->ex1 = PL_ICS_EX1(USER_PL, EX1_ICS(regs->ex1));
75 regs->faultnum = INT_SWINT_1_SIGRETURN;
80 void signal_fault(const char *type, struct pt_regs *regs,
81 void __user *frame, int sig)
83 trace_unhandled_signal(type, regs, (unsigned long)frame, SIGSEGV);
84 force_sigsegv(sig, current);
87 /* The assembly shim for this function arranges to ignore the return value. */
88 SYSCALL_DEFINE1(rt_sigreturn, struct pt_regs *, regs)
90 struct rt_sigframe __user *frame =
91 (struct rt_sigframe __user *)(regs->sp);
94 if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
96 if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
99 sigdelsetmask(&set, ~_BLOCKABLE);
100 spin_lock_irq(¤t->sighand->siglock);
101 current->blocked = set;
103 spin_unlock_irq(¤t->sighand->siglock);
105 if (restore_sigcontext(regs, &frame->uc.uc_mcontext))
108 if (do_sigaltstack(&frame->uc.uc_stack, NULL, regs->sp) == -EFAULT)
114 signal_fault("bad sigreturn frame", regs, frame, 0);
119 * Set up a signal frame.
122 int setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs)
126 for (i = 0; i < sizeof(struct pt_regs)/sizeof(long); ++i)
127 err |= __put_user(regs->regs[i], &sc->gregs[i]);
133 * Determine which stack to use..
135 static inline void __user *get_sigframe(struct k_sigaction *ka,
136 struct pt_regs *regs,
141 /* Default to using normal stack */
145 * If we are on the alternate signal stack and would overflow
146 * it, don't. Return an always-bogus address instead so we
147 * will die with SIGSEGV.
149 if (on_sig_stack(sp) && !likely(on_sig_stack(sp - frame_size)))
150 return (void __user __force *)-1UL;
152 /* This is the X/Open sanctioned signal stack switching. */
153 if (ka->sa.sa_flags & SA_ONSTACK) {
154 if (sas_ss_flags(sp) == 0)
155 sp = current->sas_ss_sp + current->sas_ss_size;
160 * Align the stack pointer according to the TILE ABI,
161 * i.e. so that on function entry (sp & 15) == 0.
164 return (void __user *) sp;
167 static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
168 sigset_t *set, struct pt_regs *regs)
170 unsigned long restorer;
171 struct rt_sigframe __user *frame;
175 frame = get_sigframe(ka, regs, sizeof(*frame));
177 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
180 usig = current_thread_info()->exec_domain
181 && current_thread_info()->exec_domain->signal_invmap
183 ? current_thread_info()->exec_domain->signal_invmap[sig]
186 /* Always write at least the signal number for the stack backtracer. */
187 if (ka->sa.sa_flags & SA_SIGINFO) {
188 /* At sigreturn time, restore the callee-save registers too. */
189 err |= copy_siginfo_to_user(&frame->info, info);
190 regs->flags |= PT_FLAGS_RESTORE_REGS;
192 err |= __put_user(info->si_signo, &frame->info.si_signo);
195 /* Create the ucontext. */
196 err |= __clear_user(&frame->save_area, sizeof(frame->save_area));
197 err |= __put_user(0, &frame->uc.uc_flags);
198 err |= __put_user(NULL, &frame->uc.uc_link);
199 err |= __put_user((void __user *)(current->sas_ss_sp),
200 &frame->uc.uc_stack.ss_sp);
201 err |= __put_user(sas_ss_flags(regs->sp),
202 &frame->uc.uc_stack.ss_flags);
203 err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
204 err |= setup_sigcontext(&frame->uc.uc_mcontext, regs);
205 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
209 restorer = VDSO_BASE;
210 if (ka->sa.sa_flags & SA_RESTORER)
211 restorer = (unsigned long) ka->sa.sa_restorer;
214 * Set up registers for signal handler.
215 * Registers that we don't modify keep the value they had from
216 * user-space at the time we took the signal.
217 * We always pass siginfo and mcontext, regardless of SA_SIGINFO,
218 * since some things rely on this (e.g. glibc's debug/segfault.c).
220 regs->pc = (unsigned long) ka->sa.sa_handler;
221 regs->ex1 = PL_ICS_EX1(USER_PL, 1); /* set crit sec in handler */
222 regs->sp = (unsigned long) frame;
224 regs->regs[0] = (unsigned long) usig;
225 regs->regs[1] = (unsigned long) &frame->info;
226 regs->regs[2] = (unsigned long) &frame->uc;
227 regs->flags |= PT_FLAGS_CALLER_SAVES;
230 * Notify any tracer that was single-stepping it.
231 * The tracer may want to single-step inside the
234 if (test_thread_flag(TIF_SINGLESTEP))
235 ptrace_notify(SIGTRAP);
240 signal_fault("bad setup frame", regs, frame, sig);
245 * OK, we're invoking a handler
248 static int handle_signal(unsigned long sig, siginfo_t *info,
249 struct k_sigaction *ka, sigset_t *oldset,
250 struct pt_regs *regs)
254 /* Are we from a system call? */
255 if (regs->faultnum == INT_SWINT_1) {
256 /* If so, check system call restarting.. */
257 switch (regs->regs[0]) {
258 case -ERESTART_RESTARTBLOCK:
259 case -ERESTARTNOHAND:
260 regs->regs[0] = -EINTR;
264 if (!(ka->sa.sa_flags & SA_RESTART)) {
265 regs->regs[0] = -EINTR;
269 case -ERESTARTNOINTR:
270 /* Reload caller-saves to restore r0..r5 and r10. */
271 regs->flags |= PT_FLAGS_CALLER_SAVES;
272 regs->regs[0] = regs->orig_r0;
277 /* Set up the stack frame */
279 if (is_compat_task())
280 ret = compat_setup_rt_frame(sig, ka, info, oldset, regs);
283 ret = setup_rt_frame(sig, ka, info, oldset, regs);
285 /* This code is only called from system calls or from
286 * the work_pending path in the return-to-user code, and
287 * either way we can re-enable interrupts unconditionally.
289 spin_lock_irq(¤t->sighand->siglock);
290 sigorsets(¤t->blocked,
291 ¤t->blocked, &ka->sa.sa_mask);
292 if (!(ka->sa.sa_flags & SA_NODEFER))
293 sigaddset(¤t->blocked, sig);
295 spin_unlock_irq(¤t->sighand->siglock);
302 * Note that 'init' is a special process: it doesn't get signals it doesn't
303 * want to handle. Thus you cannot kill init even with a SIGKILL even by
306 void do_signal(struct pt_regs *regs)
310 struct k_sigaction ka;
314 * i386 will check if we're coming from kernel mode and bail out
315 * here. In my experience this just turns weird crashes into
316 * weird spin-hangs. But if we find a case where this seems
317 * helpful, we can reinstate the check on "!user_mode(regs)".
320 if (current_thread_info()->status & TS_RESTORE_SIGMASK)
321 oldset = ¤t->saved_sigmask;
323 oldset = ¤t->blocked;
325 signr = get_signal_to_deliver(&info, &ka, regs, NULL);
327 /* Whee! Actually deliver the signal. */
328 if (handle_signal(signr, &info, &ka, oldset, regs) == 0) {
330 * A signal was successfully delivered; the saved
331 * sigmask will have been stored in the signal frame,
332 * and will be restored by sigreturn, so we can simply
333 * clear the TS_RESTORE_SIGMASK flag.
335 current_thread_info()->status &= ~TS_RESTORE_SIGMASK;
341 /* Did we come from a system call? */
342 if (regs->faultnum == INT_SWINT_1) {
343 /* Restart the system call - no handlers present */
344 switch (regs->regs[0]) {
345 case -ERESTARTNOHAND:
347 case -ERESTARTNOINTR:
348 regs->flags |= PT_FLAGS_CALLER_SAVES;
349 regs->regs[0] = regs->orig_r0;
353 case -ERESTART_RESTARTBLOCK:
354 regs->flags |= PT_FLAGS_CALLER_SAVES;
355 regs->regs[TREG_SYSCALL_NR] = __NR_restart_syscall;
361 /* If there's no signal to deliver, just put the saved sigmask back. */
362 if (current_thread_info()->status & TS_RESTORE_SIGMASK) {
363 current_thread_info()->status &= ~TS_RESTORE_SIGMASK;
364 sigprocmask(SIG_SETMASK, ¤t->saved_sigmask, NULL);
368 /* Avoid double syscall restart if there are nested signals. */
369 regs->faultnum = INT_SWINT_1_SIGRETURN;
372 int show_unhandled_signals = 1;
374 static int __init crashinfo(char *str)
381 else if (*str != '=' || strict_strtoul(++str, 0, &val) != 0)
383 show_unhandled_signals = val;
384 switch (show_unhandled_signals) {
395 pr_info("%s crash reports will be generated on the console\n", word);
398 __setup("crashinfo", crashinfo);
400 static void dump_mem(void __user *address)
403 enum { region_size = 256, bytes_per_line = 16 };
405 int found_readable_mem = 0;
408 if (!access_ok(VERIFY_READ, address, 1)) {
409 pr_err("Not dumping at address 0x%lx (kernel address)\n",
410 (unsigned long)address);
414 addr = (void __user *)
415 (((unsigned long)address & -bytes_per_line) - region_size/2);
418 for (i = 0; i < region_size;
419 addr += bytes_per_line, i += bytes_per_line) {
420 unsigned char buf[bytes_per_line];
422 if (copy_from_user(buf, addr, bytes_per_line))
424 if (!found_readable_mem) {
425 pr_err("Dumping memory around address 0x%lx:\n",
426 (unsigned long)address);
427 found_readable_mem = 1;
429 j = sprintf(line, REGFMT":", (unsigned long)addr);
430 for (k = 0; k < bytes_per_line; ++k)
431 j += sprintf(&line[j], " %02x", buf[k]);
432 pr_err("%s\n", line);
434 if (!found_readable_mem)
435 pr_err("No readable memory around address 0x%lx\n",
436 (unsigned long)address);
439 void trace_unhandled_signal(const char *type, struct pt_regs *regs,
440 unsigned long address, int sig)
442 struct task_struct *tsk = current;
444 if (show_unhandled_signals == 0)
447 /* If the signal is handled, don't show it here. */
448 if (!is_global_init(tsk)) {
449 void __user *handler =
450 tsk->sighand->action[sig-1].sa.sa_handler;
451 if (handler != SIG_IGN && handler != SIG_DFL)
455 /* Rate-limit the one-line output, not the detailed output. */
456 if (show_unhandled_signals <= 1 && !printk_ratelimit())
459 printk("%s%s[%d]: %s at %lx pc "REGFMT" signal %d",
460 task_pid_nr(tsk) > 1 ? KERN_INFO : KERN_EMERG,
461 tsk->comm, task_pid_nr(tsk), type, address, regs->pc, sig);
463 print_vma_addr(KERN_CONT " in ", regs->pc);
465 printk(KERN_CONT "\n");
467 if (show_unhandled_signals > 1) {
473 pr_err("User crash: signal %d,"
474 " trap %ld, address 0x%lx\n",
475 sig, regs->faultnum, address);
477 dump_mem((void __user *)address);
480 pr_err("User crash: signal %d, trap %ld\n",
481 sig, regs->faultnum);