- 根目录:
- arch
- tile
- kernel
- signal.c
/*
* Copyright (C) 1991, 1992 Linus Torvalds
* Copyright 2010 Tilera Corporation. All Rights Reserved.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation, version 2.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
* NON INFRINGEMENT. See the GNU General Public License for
* more details.
*/
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/smp.h>
#include <linux/kernel.h>
#include <linux/signal.h>
#include <linux/errno.h>
#include <linux/wait.h>
#include <linux/unistd.h>
#include <linux/stddef.h>
#include <linux/personality.h>
#include <linux/suspend.h>
#include <linux/ptrace.h>
#include <linux/elf.h>
#include <linux/compat.h>
#include <linux/syscalls.h>
#include <linux/uaccess.h>
#include <asm/processor.h>
#include <asm/ucontext.h>
#include <asm/sigframe.h>
#include <asm/syscalls.h>
#include <asm/vdso.h>
#include <arch/interrupts.h>
#define DEBUG_SIG 0
/*
* Do a signal return; undo the signal stack.
*/
int restore_sigcontext(struct pt_regs *regs,
struct sigcontext __user *sc)
{
int err = 0;
int i;
/* Always make any pending restarted system calls return -EINTR */
current_thread_info()->restart_block.fn = do_no_restart_syscall;
/*
* Enforce that sigcontext is like pt_regs, and doesn't mess
* up our stack alignment rules.
*/
BUILD_BUG_ON(sizeof(struct sigcontext) != sizeof(struct pt_regs));
BUILD_BUG_ON(sizeof(struct sigcontext) % 8 != 0);
for (i = 0; i < sizeof(struct pt_regs)/sizeof(long); ++i)
err |= __get_user(regs->regs[i], &sc->gregs[i]);
/* Ensure that the PL is always set to USER_PL. */
regs->ex1 = PL_ICS_EX1(USER_PL, EX1_ICS(regs->ex1));
regs->faultnum = INT_SWINT_1_SIGRETURN;
return err;
}
void signal_fault(const char *type, struct pt_regs *regs,
void __user *frame, int sig)
{
trace_unhandled_signal(type, regs, (unsigned long)frame, SIGSEGV);
force_sigsegv(sig, current);
}
/* The assembly shim for this function arranges to ignore the return value. */
SYSCALL_DEFINE0(rt_sigreturn)
{
struct pt_regs *regs = current_pt_regs();
struct rt_sigframe __user *frame =
(struct rt_sigframe __user *)(regs->sp);
sigset_t set;
if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
goto badframe;
if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
goto badframe;
set_current_blocked(&set);
if (restore_sigcontext(regs, &frame->uc.uc_mcontext))
goto badframe;
if (restore_altstack(&frame->uc.uc_stack))
goto badframe;
return 0;
badframe:
signal_fault("bad sigreturn frame", regs, frame, 0);
return 0;
}
/*
* Set up a signal frame.
*/
int setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs)
{
int i, err = 0;
for (i = 0; i < sizeof(struct pt_regs)/sizeof(long); ++i)
err |= __put_user(regs->regs[i], &sc->gregs[i]);
return err;
}
/*
* Determine which stack to use..
*/
static inline void __user *get_sigframe(struct k_sigaction *ka,
struct pt_regs *regs,
size_t frame_size)
{
unsigned long sp;
/* Default to using normal stack */
sp = regs->sp;
/*
* If we are on the alternate signal stack and would overflow
* it, don't. Return an always-bogus address instead so we
* will die with SIGSEGV.
*/
if (on_sig_stack(sp) && !likely(on_sig_stack(sp - frame_size)))
return (void __user __force *)-1UL;
/* This is the X/Open sanctioned signal stack switching. */
if (ka->sa.sa_flags & SA_ONSTACK) {
if (sas_ss_flags(sp) == 0)
sp = current->sas_ss_sp + current->sas_ss_size;
}
sp -= frame_size;
/*
* Align the stack pointer according to the TILE ABI,
* i.e. so that on function entry (sp & 15) == 0.
*/
sp &= -16UL;
return (void __user *) sp;
}
static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
sigset_t *set, struct pt_regs *regs)
{
unsigned long restorer;
struct rt_sigframe __user *frame;
int err = 0;
int usig;
frame = get_sigframe(ka, regs, sizeof(*frame));
if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
goto give_sigsegv;
usig = current_thread_info()->exec_domain
&& current_thread_info()->exec_domain->signal_invmap
&& sig < 32
? current_thread_info()->exec_domain->signal_invmap[sig]
: sig;
/* Always write at least the signal number for the stack backtracer. */
if (ka->sa.sa_flags & SA_SIGINFO) {
/* At sigreturn time, restore the callee-save registers too. */
err |= copy_siginfo_to_user(&frame->info, info);
regs->flags |= PT_FLAGS_RESTORE_REGS;
} else {
err |= __put_user(info->si_signo, &frame->info.si_signo);
}
/* Create the ucontext. */
err |= __clear_user(&frame->save_area, sizeof(frame->save_area));
err |= __put_user(0, &frame->uc.uc_flags);
err |= __put_user(NULL, &frame->uc.uc_link);
err |= __save_altstack(&frame->uc.uc_stack, regs->sp);
err |= setup_sigcontext(&frame->uc.uc_mcontext, regs);
err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
if (err)
goto give_sigsegv;
restorer = VDSO_SYM(&__vdso_rt_sigreturn);
if (ka->sa.sa_flags & SA_RESTORER)
restorer = (unsigned long) ka->sa.sa_restorer;
/*
* Set up registers for signal handler.
* Registers that we don't modify keep the value they had from
* user-space at the time we took the signal.
* We always pass siginfo and mcontext, regardless of SA_SIGINFO,
* since some things rely on this (e.g. glibc's debug/segfault.c).
*/
regs->pc = (unsigned long) ka->sa.sa_handler;
regs->ex1 = PL_ICS_EX1(USER_PL, 1); /* set crit sec in handler */
regs->sp = (unsigned long) frame;
regs->lr = restorer;
regs->regs[0] = (unsigned long) usig;
regs->regs[1] = (unsigned long) &frame->info;
regs->regs[2] = (unsigned long) &frame->uc;
regs->flags |= PT_FLAGS_CALLER_SAVES;
return 0;
give_sigsegv:
signal_fault("bad setup frame", regs, frame, sig);
return -EFAULT;
}
/*
* OK, we're invoking a handler
*/
static void handle_signal(unsigned long sig, siginfo_t *info,
struct k_sigaction *ka,
struct pt_regs *regs)
{
sigset_t *oldset = sigmask_to_save();
int ret;
/* Are we from a system call? */
if (regs->faultnum == INT_SWINT_1) {
/* If so, check system call restarting.. */
switch (regs->regs[0]) {
case -ERESTART_RESTARTBLOCK:
case -ERESTARTNOHAND:
regs->regs[0] = -EINTR;
break;
case -ERESTARTSYS:
if (!(ka->sa.sa_flags & SA_RESTART)) {
regs->regs[0] = -EINTR;
break;
}
/* fallthrough */
case -ERESTARTNOINTR:
/* Reload caller-saves to restore r0..r5 and r10. */
regs->flags |= PT_FLAGS_CALLER_SAVES;
regs->regs[0] = regs->orig_r0;
regs->pc -= 8;
}
}
/* Set up the stack frame */
#ifdef CONFIG_COMPAT
if (is_compat_task())
ret = compat_setup_rt_frame(sig, ka, info, oldset, regs);
else
#endif
ret = setup_rt_frame(sig, ka, info, oldset, regs);
if (ret)
return;
signal_delivered(sig, info, ka, regs,
test_thread_flag(TIF_SINGLESTEP));
}
/*
* Note that 'init' is a special process: it doesn't get signals it doesn't
* want to handle. Thus you cannot kill init even with a SIGKILL even by
* mistake.
*/
void do_signal(struct pt_regs *regs)
{
siginfo_t info;
int signr;
struct k_sigaction ka;
/*
* i386 will check if we're coming from kernel mode and bail out
* here. In my experience this just turns weird crashes into
* weird spin-hangs. But if we find a case where this seems
* helpful, we can reinstate the check on "!user_mode(regs)".
*/
signr = get_signal_to_deliver(&info, &ka, regs, NULL);
if (signr > 0) {
/* Whee! Actually deliver the signal. */
handle_signal(signr, &info, &ka, regs);
goto done;
}
/* Did we come from a system call? */
if (regs->faultnum == INT_SWINT_1) {
/* Restart the system call - no handlers present */
switch (regs->regs[0]) {
case -ERESTARTNOHAND:
case -ERESTARTSYS:
case -ERESTARTNOINTR:
regs->flags |= PT_FLAGS_CALLER_SAVES;
regs->regs[0] = regs->orig_r0;
regs->pc -= 8;
break;
case -ERESTART_RESTARTBLOCK:
regs->flags |= PT_FLAGS_CALLER_SAVES;
regs->regs[TREG_SYSCALL_NR] = __NR_restart_syscall;
regs->pc -= 8;
break;
}
}
/* If there's no signal to deliver, just put the saved sigmask back. */
restore_saved_sigmask();
done:
/* Avoid double syscall restart if there are nested signals. */
regs->faultnum = INT_SWINT_1_SIGRETURN;
}
int show_unhandled_signals = 1;
static int __init crashinfo(char *str)
{
unsigned long val;
const char *word;
if (*str == '\0')
val = 2;
else if (*str != '=' || strict_strtoul(++str, 0, &val) != 0)
return 0;
show_unhandled_signals = val;
switch (show_unhandled_signals) {
case 0:
word = "No";
break;
case 1:
word = "One-line";
break;
default:
word = "Detailed";
break;
}
pr_info("%s crash reports will be generated on the console\n", word);
return 1;
}
__setup("crashinfo", crashinfo);
static void dump_mem(void __user *address)
{
void __user *addr;
enum { region_size = 256, bytes_per_line = 16 };
int i, j, k;
int found_readable_mem = 0;
pr_err("\n");
if (!access_ok(VERIFY_READ, address, 1)) {
pr_err("Not dumping at address 0x%lx (kernel address)\n",
(unsigned long)address);
return;
}
addr = (void __user *)
(((unsigned long)address & -bytes_per_line) - region_size/2);
if (addr > address)
addr = NULL;
for (i = 0; i < region_size;
addr += bytes_per_line, i += bytes_per_line) {
unsigned char buf[bytes_per_line];
char line[100];
if (copy_from_user(buf, addr, bytes_per_line))
continue;
if (!found_readable_mem) {
pr_err("Dumping memory around address 0x%lx:\n",
(unsigned long)address);
found_readable_mem = 1;
}
j = sprintf(line, REGFMT":", (unsigned long)addr);
for (k = 0; k < bytes_per_line; ++k)
j += sprintf(&line[j], " %02x", buf[k]);
pr_err("%s\n", line);
}
if (!found_readable_mem)
pr_err("No readable memory around address 0x%lx\n",
(unsigned long)address);
}
void trace_unhandled_signal(const char *type, struct pt_regs *regs,
unsigned long address, int sig)
{
struct task_struct *tsk = current;
if (show_unhandled_signals == 0)
return;
/* If the signal is handled, don't show it here. */
if (!is_global_init(tsk)) {
void __user *handler =
tsk->sighand->action[sig-1].sa.sa_handler;
if (handler != SIG_IGN && handler != SIG_DFL)
return;
}
/* Rate-limit the one-line output, not the detailed output. */
if (show_unhandled_signals <= 1 && !printk_ratelimit())
return;
printk("%s%s[%d]: %s at %lx pc "REGFMT" signal %d",
task_pid_nr(tsk) > 1 ? KERN_INFO : KERN_EMERG,
tsk->comm, task_pid_nr(tsk), type, address, regs->pc, sig);
print_vma_addr(KERN_CONT " in ", regs->pc);
printk(KERN_CONT "\n");
if (show_unhandled_signals > 1) {
switch (sig) {
case SIGILL:
case SIGFPE:
case SIGSEGV:
case SIGBUS:
pr_err("User crash: signal %d,"
" trap %ld, address 0x%lx\n",
sig, regs->faultnum, address);
show_regs(regs);
dump_mem((void __user *)address);
break;
default:
pr_err("User crash: signal %d, trap %ld\n",
sig, regs->faultnum);
break;
}
}
}