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>
41 * Do a signal return; undo the signal stack.
44 int restore_sigcontext(struct pt_regs *regs,
45 struct sigcontext __user *sc)
50 /* Always make any pending restarted system calls return -EINTR */
51 current_thread_info()->restart_block.fn = do_no_restart_syscall;
54 * Enforce that sigcontext is like pt_regs, and doesn't mess
55 * up our stack alignment rules.
57 BUILD_BUG_ON(sizeof(struct sigcontext) != sizeof(struct pt_regs));
58 BUILD_BUG_ON(sizeof(struct sigcontext) % 8 != 0);
60 for (i = 0; i < sizeof(struct pt_regs)/sizeof(long); ++i)
61 err |= __get_user(regs->regs[i], &sc->gregs[i]);
63 /* Ensure that the PL is always set to USER_PL. */
64 regs->ex1 = PL_ICS_EX1(USER_PL, EX1_ICS(regs->ex1));
66 regs->faultnum = INT_SWINT_1_SIGRETURN;
71 void signal_fault(const char *type, struct pt_regs *regs,
72 void __user *frame, int sig)
74 trace_unhandled_signal(type, regs, (unsigned long)frame, SIGSEGV);
75 force_sigsegv(sig, current);
78 /* The assembly shim for this function arranges to ignore the return value. */
79 SYSCALL_DEFINE0(rt_sigreturn)
81 struct pt_regs *regs = current_pt_regs();
82 struct rt_sigframe __user *frame =
83 (struct rt_sigframe __user *)(regs->sp);
86 if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
88 if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
91 set_current_blocked(&set);
93 if (restore_sigcontext(regs, &frame->uc.uc_mcontext))
96 if (restore_altstack(&frame->uc.uc_stack))
102 signal_fault("bad sigreturn frame", regs, frame, 0);
107 * Set up a signal frame.
110 int setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs)
114 for (i = 0; i < sizeof(struct pt_regs)/sizeof(long); ++i)
115 err |= __put_user(regs->regs[i], &sc->gregs[i]);
121 * Determine which stack to use..
123 static inline void __user *get_sigframe(struct k_sigaction *ka,
124 struct pt_regs *regs,
129 /* Default to using normal stack */
133 * If we are on the alternate signal stack and would overflow
134 * it, don't. Return an always-bogus address instead so we
135 * will die with SIGSEGV.
137 if (on_sig_stack(sp) && !likely(on_sig_stack(sp - frame_size)))
138 return (void __user __force *)-1UL;
140 /* This is the X/Open sanctioned signal stack switching. */
141 if (ka->sa.sa_flags & SA_ONSTACK) {
142 if (sas_ss_flags(sp) == 0)
143 sp = current->sas_ss_sp + current->sas_ss_size;
148 * Align the stack pointer according to the TILE ABI,
149 * i.e. so that on function entry (sp & 15) == 0.
152 return (void __user *) sp;
155 static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
156 sigset_t *set, struct pt_regs *regs)
158 unsigned long restorer;
159 struct rt_sigframe __user *frame;
163 frame = get_sigframe(ka, regs, sizeof(*frame));
165 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
168 usig = current_thread_info()->exec_domain
169 && current_thread_info()->exec_domain->signal_invmap
171 ? current_thread_info()->exec_domain->signal_invmap[sig]
174 /* Always write at least the signal number for the stack backtracer. */
175 if (ka->sa.sa_flags & SA_SIGINFO) {
176 /* At sigreturn time, restore the callee-save registers too. */
177 err |= copy_siginfo_to_user(&frame->info, info);
178 regs->flags |= PT_FLAGS_RESTORE_REGS;
180 err |= __put_user(info->si_signo, &frame->info.si_signo);
183 /* Create the ucontext. */
184 err |= __clear_user(&frame->save_area, sizeof(frame->save_area));
185 err |= __put_user(0, &frame->uc.uc_flags);
186 err |= __put_user(NULL, &frame->uc.uc_link);
187 err |= __save_altstack(&frame->uc.uc_stack, regs->sp);
188 err |= setup_sigcontext(&frame->uc.uc_mcontext, regs);
189 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
193 restorer = VDSO_BASE;
194 if (ka->sa.sa_flags & SA_RESTORER)
195 restorer = (unsigned long) ka->sa.sa_restorer;
198 * Set up registers for signal handler.
199 * Registers that we don't modify keep the value they had from
200 * user-space at the time we took the signal.
201 * We always pass siginfo and mcontext, regardless of SA_SIGINFO,
202 * since some things rely on this (e.g. glibc's debug/segfault.c).
204 regs->pc = (unsigned long) ka->sa.sa_handler;
205 regs->ex1 = PL_ICS_EX1(USER_PL, 1); /* set crit sec in handler */
206 regs->sp = (unsigned long) frame;
208 regs->regs[0] = (unsigned long) usig;
209 regs->regs[1] = (unsigned long) &frame->info;
210 regs->regs[2] = (unsigned long) &frame->uc;
211 regs->flags |= PT_FLAGS_CALLER_SAVES;
215 signal_fault("bad setup frame", regs, frame, sig);
220 * OK, we're invoking a handler
223 static void handle_signal(unsigned long sig, siginfo_t *info,
224 struct k_sigaction *ka,
225 struct pt_regs *regs)
227 sigset_t *oldset = sigmask_to_save();
230 /* Are we from a system call? */
231 if (regs->faultnum == INT_SWINT_1) {
232 /* If so, check system call restarting.. */
233 switch (regs->regs[0]) {
234 case -ERESTART_RESTARTBLOCK:
235 case -ERESTARTNOHAND:
236 regs->regs[0] = -EINTR;
240 if (!(ka->sa.sa_flags & SA_RESTART)) {
241 regs->regs[0] = -EINTR;
245 case -ERESTARTNOINTR:
246 /* Reload caller-saves to restore r0..r5 and r10. */
247 regs->flags |= PT_FLAGS_CALLER_SAVES;
248 regs->regs[0] = regs->orig_r0;
253 /* Set up the stack frame */
255 if (is_compat_task())
256 ret = compat_setup_rt_frame(sig, ka, info, oldset, regs);
259 ret = setup_rt_frame(sig, ka, info, oldset, regs);
262 signal_delivered(sig, info, ka, regs,
263 test_thread_flag(TIF_SINGLESTEP));
267 * Note that 'init' is a special process: it doesn't get signals it doesn't
268 * want to handle. Thus you cannot kill init even with a SIGKILL even by
271 void do_signal(struct pt_regs *regs)
275 struct k_sigaction ka;
278 * i386 will check if we're coming from kernel mode and bail out
279 * here. In my experience this just turns weird crashes into
280 * weird spin-hangs. But if we find a case where this seems
281 * helpful, we can reinstate the check on "!user_mode(regs)".
284 signr = get_signal_to_deliver(&info, &ka, regs, NULL);
286 /* Whee! Actually deliver the signal. */
287 handle_signal(signr, &info, &ka, regs);
291 /* Did we come from a system call? */
292 if (regs->faultnum == INT_SWINT_1) {
293 /* Restart the system call - no handlers present */
294 switch (regs->regs[0]) {
295 case -ERESTARTNOHAND:
297 case -ERESTARTNOINTR:
298 regs->flags |= PT_FLAGS_CALLER_SAVES;
299 regs->regs[0] = regs->orig_r0;
303 case -ERESTART_RESTARTBLOCK:
304 regs->flags |= PT_FLAGS_CALLER_SAVES;
305 regs->regs[TREG_SYSCALL_NR] = __NR_restart_syscall;
311 /* If there's no signal to deliver, just put the saved sigmask back. */
312 restore_saved_sigmask();
315 /* Avoid double syscall restart if there are nested signals. */
316 regs->faultnum = INT_SWINT_1_SIGRETURN;
319 int show_unhandled_signals = 1;
321 static int __init crashinfo(char *str)
328 else if (*str != '=' || strict_strtoul(++str, 0, &val) != 0)
330 show_unhandled_signals = val;
331 switch (show_unhandled_signals) {
342 pr_info("%s crash reports will be generated on the console\n", word);
345 __setup("crashinfo", crashinfo);
347 static void dump_mem(void __user *address)
350 enum { region_size = 256, bytes_per_line = 16 };
352 int found_readable_mem = 0;
355 if (!access_ok(VERIFY_READ, address, 1)) {
356 pr_err("Not dumping at address 0x%lx (kernel address)\n",
357 (unsigned long)address);
361 addr = (void __user *)
362 (((unsigned long)address & -bytes_per_line) - region_size/2);
365 for (i = 0; i < region_size;
366 addr += bytes_per_line, i += bytes_per_line) {
367 unsigned char buf[bytes_per_line];
369 if (copy_from_user(buf, addr, bytes_per_line))
371 if (!found_readable_mem) {
372 pr_err("Dumping memory around address 0x%lx:\n",
373 (unsigned long)address);
374 found_readable_mem = 1;
376 j = sprintf(line, REGFMT":", (unsigned long)addr);
377 for (k = 0; k < bytes_per_line; ++k)
378 j += sprintf(&line[j], " %02x", buf[k]);
379 pr_err("%s\n", line);
381 if (!found_readable_mem)
382 pr_err("No readable memory around address 0x%lx\n",
383 (unsigned long)address);
386 void trace_unhandled_signal(const char *type, struct pt_regs *regs,
387 unsigned long address, int sig)
389 struct task_struct *tsk = current;
391 if (show_unhandled_signals == 0)
394 /* If the signal is handled, don't show it here. */
395 if (!is_global_init(tsk)) {
396 void __user *handler =
397 tsk->sighand->action[sig-1].sa.sa_handler;
398 if (handler != SIG_IGN && handler != SIG_DFL)
402 /* Rate-limit the one-line output, not the detailed output. */
403 if (show_unhandled_signals <= 1 && !printk_ratelimit())
406 printk("%s%s[%d]: %s at %lx pc "REGFMT" signal %d",
407 task_pid_nr(tsk) > 1 ? KERN_INFO : KERN_EMERG,
408 tsk->comm, task_pid_nr(tsk), type, address, regs->pc, sig);
410 print_vma_addr(KERN_CONT " in ", regs->pc);
412 printk(KERN_CONT "\n");
414 if (show_unhandled_signals > 1) {
420 pr_err("User crash: signal %d,"
421 " trap %ld, address 0x%lx\n",
422 sig, regs->faultnum, address);
424 dump_mem((void __user *)address);
427 pr_err("User crash: signal %d, trap %ld\n",
428 sig, regs->faultnum);