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 SYSCALL_DEFINE2(sigaltstack, const stack_t __user *, uss,
41 stack_t __user *, uoss)
43 return do_sigaltstack(uss, uoss, current_pt_regs()->sp);
48 * Do a signal return; undo the signal stack.
51 int restore_sigcontext(struct pt_regs *regs,
52 struct sigcontext __user *sc)
57 /* Always make any pending restarted system calls return -EINTR */
58 current_thread_info()->restart_block.fn = do_no_restart_syscall;
61 * Enforce that sigcontext is like pt_regs, and doesn't mess
62 * up our stack alignment rules.
64 BUILD_BUG_ON(sizeof(struct sigcontext) != sizeof(struct pt_regs));
65 BUILD_BUG_ON(sizeof(struct sigcontext) % 8 != 0);
67 for (i = 0; i < sizeof(struct pt_regs)/sizeof(long); ++i)
68 err |= __get_user(regs->regs[i], &sc->gregs[i]);
70 /* Ensure that the PL is always set to USER_PL. */
71 regs->ex1 = PL_ICS_EX1(USER_PL, EX1_ICS(regs->ex1));
73 regs->faultnum = INT_SWINT_1_SIGRETURN;
78 void signal_fault(const char *type, struct pt_regs *regs,
79 void __user *frame, int sig)
81 trace_unhandled_signal(type, regs, (unsigned long)frame, SIGSEGV);
82 force_sigsegv(sig, current);
85 /* The assembly shim for this function arranges to ignore the return value. */
86 SYSCALL_DEFINE0(rt_sigreturn)
88 struct pt_regs *regs = current_pt_regs();
89 struct rt_sigframe __user *frame =
90 (struct rt_sigframe __user *)(regs->sp);
93 if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
95 if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
98 set_current_blocked(&set);
100 if (restore_sigcontext(regs, &frame->uc.uc_mcontext))
103 if (do_sigaltstack(&frame->uc.uc_stack, NULL, regs->sp) == -EFAULT)
109 signal_fault("bad sigreturn frame", regs, frame, 0);
114 * Set up a signal frame.
117 int setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs)
121 for (i = 0; i < sizeof(struct pt_regs)/sizeof(long); ++i)
122 err |= __put_user(regs->regs[i], &sc->gregs[i]);
128 * Determine which stack to use..
130 static inline void __user *get_sigframe(struct k_sigaction *ka,
131 struct pt_regs *regs,
136 /* Default to using normal stack */
140 * If we are on the alternate signal stack and would overflow
141 * it, don't. Return an always-bogus address instead so we
142 * will die with SIGSEGV.
144 if (on_sig_stack(sp) && !likely(on_sig_stack(sp - frame_size)))
145 return (void __user __force *)-1UL;
147 /* This is the X/Open sanctioned signal stack switching. */
148 if (ka->sa.sa_flags & SA_ONSTACK) {
149 if (sas_ss_flags(sp) == 0)
150 sp = current->sas_ss_sp + current->sas_ss_size;
155 * Align the stack pointer according to the TILE ABI,
156 * i.e. so that on function entry (sp & 15) == 0.
159 return (void __user *) sp;
162 static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
163 sigset_t *set, struct pt_regs *regs)
165 unsigned long restorer;
166 struct rt_sigframe __user *frame;
170 frame = get_sigframe(ka, regs, sizeof(*frame));
172 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
175 usig = current_thread_info()->exec_domain
176 && current_thread_info()->exec_domain->signal_invmap
178 ? current_thread_info()->exec_domain->signal_invmap[sig]
181 /* Always write at least the signal number for the stack backtracer. */
182 if (ka->sa.sa_flags & SA_SIGINFO) {
183 /* At sigreturn time, restore the callee-save registers too. */
184 err |= copy_siginfo_to_user(&frame->info, info);
185 regs->flags |= PT_FLAGS_RESTORE_REGS;
187 err |= __put_user(info->si_signo, &frame->info.si_signo);
190 /* Create the ucontext. */
191 err |= __clear_user(&frame->save_area, sizeof(frame->save_area));
192 err |= __put_user(0, &frame->uc.uc_flags);
193 err |= __put_user(NULL, &frame->uc.uc_link);
194 err |= __put_user((void __user *)(current->sas_ss_sp),
195 &frame->uc.uc_stack.ss_sp);
196 err |= __put_user(sas_ss_flags(regs->sp),
197 &frame->uc.uc_stack.ss_flags);
198 err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
199 err |= setup_sigcontext(&frame->uc.uc_mcontext, regs);
200 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
204 restorer = VDSO_BASE;
205 if (ka->sa.sa_flags & SA_RESTORER)
206 restorer = (unsigned long) ka->sa.sa_restorer;
209 * Set up registers for signal handler.
210 * Registers that we don't modify keep the value they had from
211 * user-space at the time we took the signal.
212 * We always pass siginfo and mcontext, regardless of SA_SIGINFO,
213 * since some things rely on this (e.g. glibc's debug/segfault.c).
215 regs->pc = (unsigned long) ka->sa.sa_handler;
216 regs->ex1 = PL_ICS_EX1(USER_PL, 1); /* set crit sec in handler */
217 regs->sp = (unsigned long) frame;
219 regs->regs[0] = (unsigned long) usig;
220 regs->regs[1] = (unsigned long) &frame->info;
221 regs->regs[2] = (unsigned long) &frame->uc;
222 regs->flags |= PT_FLAGS_CALLER_SAVES;
226 signal_fault("bad setup frame", regs, frame, sig);
231 * OK, we're invoking a handler
234 static void handle_signal(unsigned long sig, siginfo_t *info,
235 struct k_sigaction *ka,
236 struct pt_regs *regs)
238 sigset_t *oldset = sigmask_to_save();
241 /* Are we from a system call? */
242 if (regs->faultnum == INT_SWINT_1) {
243 /* If so, check system call restarting.. */
244 switch (regs->regs[0]) {
245 case -ERESTART_RESTARTBLOCK:
246 case -ERESTARTNOHAND:
247 regs->regs[0] = -EINTR;
251 if (!(ka->sa.sa_flags & SA_RESTART)) {
252 regs->regs[0] = -EINTR;
256 case -ERESTARTNOINTR:
257 /* Reload caller-saves to restore r0..r5 and r10. */
258 regs->flags |= PT_FLAGS_CALLER_SAVES;
259 regs->regs[0] = regs->orig_r0;
264 /* Set up the stack frame */
266 if (is_compat_task())
267 ret = compat_setup_rt_frame(sig, ka, info, oldset, regs);
270 ret = setup_rt_frame(sig, ka, info, oldset, regs);
273 signal_delivered(sig, info, ka, regs,
274 test_thread_flag(TIF_SINGLESTEP));
278 * Note that 'init' is a special process: it doesn't get signals it doesn't
279 * want to handle. Thus you cannot kill init even with a SIGKILL even by
282 void do_signal(struct pt_regs *regs)
286 struct k_sigaction ka;
289 * i386 will check if we're coming from kernel mode and bail out
290 * here. In my experience this just turns weird crashes into
291 * weird spin-hangs. But if we find a case where this seems
292 * helpful, we can reinstate the check on "!user_mode(regs)".
295 signr = get_signal_to_deliver(&info, &ka, regs, NULL);
297 /* Whee! Actually deliver the signal. */
298 handle_signal(signr, &info, &ka, regs);
302 /* Did we come from a system call? */
303 if (regs->faultnum == INT_SWINT_1) {
304 /* Restart the system call - no handlers present */
305 switch (regs->regs[0]) {
306 case -ERESTARTNOHAND:
308 case -ERESTARTNOINTR:
309 regs->flags |= PT_FLAGS_CALLER_SAVES;
310 regs->regs[0] = regs->orig_r0;
314 case -ERESTART_RESTARTBLOCK:
315 regs->flags |= PT_FLAGS_CALLER_SAVES;
316 regs->regs[TREG_SYSCALL_NR] = __NR_restart_syscall;
322 /* If there's no signal to deliver, just put the saved sigmask back. */
323 restore_saved_sigmask();
326 /* Avoid double syscall restart if there are nested signals. */
327 regs->faultnum = INT_SWINT_1_SIGRETURN;
330 int show_unhandled_signals = 1;
332 static int __init crashinfo(char *str)
339 else if (*str != '=' || strict_strtoul(++str, 0, &val) != 0)
341 show_unhandled_signals = val;
342 switch (show_unhandled_signals) {
353 pr_info("%s crash reports will be generated on the console\n", word);
356 __setup("crashinfo", crashinfo);
358 static void dump_mem(void __user *address)
361 enum { region_size = 256, bytes_per_line = 16 };
363 int found_readable_mem = 0;
366 if (!access_ok(VERIFY_READ, address, 1)) {
367 pr_err("Not dumping at address 0x%lx (kernel address)\n",
368 (unsigned long)address);
372 addr = (void __user *)
373 (((unsigned long)address & -bytes_per_line) - region_size/2);
376 for (i = 0; i < region_size;
377 addr += bytes_per_line, i += bytes_per_line) {
378 unsigned char buf[bytes_per_line];
380 if (copy_from_user(buf, addr, bytes_per_line))
382 if (!found_readable_mem) {
383 pr_err("Dumping memory around address 0x%lx:\n",
384 (unsigned long)address);
385 found_readable_mem = 1;
387 j = sprintf(line, REGFMT":", (unsigned long)addr);
388 for (k = 0; k < bytes_per_line; ++k)
389 j += sprintf(&line[j], " %02x", buf[k]);
390 pr_err("%s\n", line);
392 if (!found_readable_mem)
393 pr_err("No readable memory around address 0x%lx\n",
394 (unsigned long)address);
397 void trace_unhandled_signal(const char *type, struct pt_regs *regs,
398 unsigned long address, int sig)
400 struct task_struct *tsk = current;
402 if (show_unhandled_signals == 0)
405 /* If the signal is handled, don't show it here. */
406 if (!is_global_init(tsk)) {
407 void __user *handler =
408 tsk->sighand->action[sig-1].sa.sa_handler;
409 if (handler != SIG_IGN && handler != SIG_DFL)
413 /* Rate-limit the one-line output, not the detailed output. */
414 if (show_unhandled_signals <= 1 && !printk_ratelimit())
417 printk("%s%s[%d]: %s at %lx pc "REGFMT" signal %d",
418 task_pid_nr(tsk) > 1 ? KERN_INFO : KERN_EMERG,
419 tsk->comm, task_pid_nr(tsk), type, address, regs->pc, sig);
421 print_vma_addr(KERN_CONT " in ", regs->pc);
423 printk(KERN_CONT "\n");
425 if (show_unhandled_signals > 1) {
431 pr_err("User crash: signal %d,"
432 " trap %ld, address 0x%lx\n",
433 sig, regs->faultnum, address);
435 dump_mem((void __user *)address);
438 pr_err("User crash: signal %d, trap %ld\n",
439 sig, regs->faultnum);