diff options
author | Chris Metcalf <cmetcalf@tilera.com> | 2011-05-16 14:23:44 -0400 |
---|---|---|
committer | Chris Metcalf <cmetcalf@tilera.com> | 2011-05-19 22:55:59 -0400 |
commit | 571d76acdab95876aeff869ab6449f826c23aa43 (patch) | |
tree | b52ceacfa83b1ab4c5a6950007ce8be03cec192e /arch/tile/kernel/signal.c | |
parent | 8aaf1dda42576b0f8dffb004065baa806f4df9b6 (diff) | |
download | op-kernel-dev-571d76acdab95876aeff869ab6449f826c23aa43.zip op-kernel-dev-571d76acdab95876aeff869ab6449f826c23aa43.tar.gz |
arch/tile: support signal "exception-trace" hook
This change adds support for /proc/sys/debug/exception-trace to tile.
Like x86 and sparc, by default it is set to "1", generating a one-line
printk whenever a user process crashes. By setting it to "2", we get
a much more complete userspace diagnostic at crash time, including
a user-space backtrace, register dump, and memory dump around the
address of the crash.
Some vestiges of the Tilera-internal version of this support are
removed with this patch (the show_crashinfo variable and the
arch_coredump_signal function). We retain a "crashinfo" boot parameter
which allows you to set the boot-time value of exception-trace.
Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
Diffstat (limited to 'arch/tile/kernel/signal.c')
-rw-r--r-- | arch/tile/kernel/signal.c | 128 |
1 files changed, 124 insertions, 4 deletions
diff --git a/arch/tile/kernel/signal.c b/arch/tile/kernel/signal.c index 1260321..bedaf4e 100644 --- a/arch/tile/kernel/signal.c +++ b/arch/tile/kernel/signal.c @@ -39,7 +39,6 @@ #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP))) - SYSCALL_DEFINE3(sigaltstack, const stack_t __user *, uss, stack_t __user *, uoss, struct pt_regs *, regs) { @@ -78,6 +77,13 @@ int restore_sigcontext(struct pt_regs *regs, 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_DEFINE1(rt_sigreturn, struct pt_regs *, regs) { @@ -105,7 +111,7 @@ SYSCALL_DEFINE1(rt_sigreturn, struct pt_regs *, regs) return 0; badframe: - force_sig(SIGSEGV, current); + signal_fault("bad sigreturn frame", regs, frame, 0); return 0; } @@ -231,7 +237,7 @@ static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info, return 0; give_sigsegv: - force_sigsegv(sig, current); + signal_fault("bad setup frame", regs, frame, sig); return -EFAULT; } @@ -245,7 +251,6 @@ static int handle_signal(unsigned long sig, siginfo_t *info, { int ret; - /* Are we from a system call? */ if (regs->faultnum == INT_SWINT_1) { /* If so, check system call restarting.. */ @@ -363,3 +368,118 @@ 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; + } + } +} |