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authorAnton Blanchard <anton@samba.org>2011-11-30 00:23:13 +0000
committerBenjamin Herrenschmidt <benh@kernel.crashing.org>2011-12-08 14:02:23 +1100
commit760ca4dc90e624eb8f7ff85a5925151e25577758 (patch)
treeecdcf387c51b5752206fb546945b1f1ccd27b884 /arch/powerpc/kernel/traps.c
parent8c27474a252e84e8a71ae4a43e18f0193a08e3f7 (diff)
powerpc: Rework die()
Our die() code was based off a very old x86 version. Update it to mirror the current x86 code. Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Diffstat (limited to 'arch/powerpc/kernel/traps.c')
-rw-r--r--arch/powerpc/kernel/traps.c128
1 files changed, 73 insertions, 55 deletions
diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c
index 014f88f03d3..c091527efd8 100644
--- a/arch/powerpc/kernel/traps.c
+++ b/arch/powerpc/kernel/traps.c
@@ -98,18 +98,14 @@ static void pmac_backlight_unblank(void)
static inline void pmac_backlight_unblank(void) { }
#endif
-int die(const char *str, struct pt_regs *regs, long err)
+static arch_spinlock_t die_lock = __ARCH_SPIN_LOCK_UNLOCKED;
+static int die_owner = -1;
+static unsigned int die_nest_count;
+static int die_counter;
+
+static unsigned __kprobes long oops_begin(struct pt_regs *regs)
{
- static struct {
- raw_spinlock_t lock;
- u32 lock_owner;
- int lock_owner_depth;
- } die = {
- .lock = __RAW_SPIN_LOCK_UNLOCKED(die.lock),
- .lock_owner = -1,
- .lock_owner_depth = 0
- };
- static int die_counter;
+ int cpu;
unsigned long flags;
if (debugger(regs))
@@ -117,50 +113,37 @@ int die(const char *str, struct pt_regs *regs, long err)
oops_enter();
- if (die.lock_owner != raw_smp_processor_id()) {
- console_verbose();
- raw_spin_lock_irqsave(&die.lock, flags);
- die.lock_owner = smp_processor_id();
- die.lock_owner_depth = 0;
- bust_spinlocks(1);
- if (machine_is(powermac))
- pmac_backlight_unblank();
- } else {
- local_save_flags(flags);
- }
-
- if (++die.lock_owner_depth < 3) {
- printk("Oops: %s, sig: %ld [#%d]\n", str, err, ++die_counter);
-#ifdef CONFIG_PREEMPT
- printk("PREEMPT ");
-#endif
-#ifdef CONFIG_SMP
- printk("SMP NR_CPUS=%d ", NR_CPUS);
-#endif
-#ifdef CONFIG_DEBUG_PAGEALLOC
- printk("DEBUG_PAGEALLOC ");
-#endif
-#ifdef CONFIG_NUMA
- printk("NUMA ");
-#endif
- printk("%s\n", ppc_md.name ? ppc_md.name : "");
-
- if (notify_die(DIE_OOPS, str, regs, err, 255,
- SIGSEGV) == NOTIFY_STOP)
- return 1;
-
- print_modules();
- show_regs(regs);
- } else {
- printk("Recursive die() failure, output suppressed\n");
+ /* racy, but better than risking deadlock. */
+ raw_local_irq_save(flags);
+ cpu = smp_processor_id();
+ if (!arch_spin_trylock(&die_lock)) {
+ if (cpu == die_owner)
+ /* nested oops. should stop eventually */;
+ else
+ arch_spin_lock(&die_lock);
}
+ die_nest_count++;
+ die_owner = cpu;
+ console_verbose();
+ bust_spinlocks(1);
+ if (machine_is(powermac))
+ pmac_backlight_unblank();
+ return flags;
+}
+static void __kprobes oops_end(unsigned long flags, struct pt_regs *regs,
+ int signr)
+{
bust_spinlocks(0);
- die.lock_owner = -1;
+ die_owner = -1;
add_taint(TAINT_DIE);
+ die_nest_count--;
oops_exit();
printk("\n");
- raw_spin_unlock_irqrestore(&die.lock, flags);
+ if (!die_nest_count)
+ /* Nest count reaches zero, release the lock. */
+ arch_spin_unlock(&die_lock);
+ raw_local_irq_restore(flags);
/*
* A system reset (0x100) is a request to dump, so we always send
@@ -177,6 +160,9 @@ int die(const char *str, struct pt_regs *regs, long err)
crash_kexec_secondary(regs);
}
+ if (!signr)
+ return;
+
/*
* While our oops output is serialised by a spinlock, output
* from panic() called below can race and corrupt it. If we
@@ -190,15 +176,46 @@ int die(const char *str, struct pt_regs *regs, long err)
if (in_interrupt())
panic("Fatal exception in interrupt");
-
if (panic_on_oops)
panic("Fatal exception");
+ do_exit(signr);
+}
- do_exit(err);
+static int __kprobes __die(const char *str, struct pt_regs *regs, long err)
+{
+ printk("Oops: %s, sig: %ld [#%d]\n", str, err, ++die_counter);
+#ifdef CONFIG_PREEMPT
+ printk("PREEMPT ");
+#endif
+#ifdef CONFIG_SMP
+ printk("SMP NR_CPUS=%d ", NR_CPUS);
+#endif
+#ifdef CONFIG_DEBUG_PAGEALLOC
+ printk("DEBUG_PAGEALLOC ");
+#endif
+#ifdef CONFIG_NUMA
+ printk("NUMA ");
+#endif
+ printk("%s\n", ppc_md.name ? ppc_md.name : "");
+
+ if (notify_die(DIE_OOPS, str, regs, err, 255, SIGSEGV) == NOTIFY_STOP)
+ return 1;
+
+ print_modules();
+ show_regs(regs);
return 0;
}
+void die(const char *str, struct pt_regs *regs, long err)
+{
+ unsigned long flags = oops_begin(regs);
+
+ if (__die(str, regs, err))
+ err = 0;
+ oops_end(flags, regs, err);
+}
+
void user_single_step_siginfo(struct task_struct *tsk,
struct pt_regs *regs, siginfo_t *info)
{
@@ -217,10 +234,11 @@ void _exception(int signr, struct pt_regs *regs, int code, unsigned long addr)
"at %016lx nip %016lx lr %016lx code %x\n";
if (!user_mode(regs)) {
- if (die("Exception in kernel mode", regs, signr))
- return;
- } else if (show_unhandled_signals &&
- unhandled_signal(current, signr)) {
+ die("Exception in kernel mode", regs, signr);
+ return;
+ }
+
+ if (show_unhandled_signals && unhandled_signal(current, signr)) {
printk_ratelimited(regs->msr & MSR_64BIT ? fmt64 : fmt32,
current->comm, current->pid, signr,
addr, regs->nip, regs->link, code);