X-Git-Url: http://git.cascardo.info/?a=blobdiff_plain;f=kernel%2Fpanic.c;h=535c96510a448f351dc89f3a36c01b2372f0decf;hb=45e876f794e8e566bf827c25ef0791875081724f;hp=fa400852bf6ca318b4b1e843f8b4f6967ce262b3;hpb=8c6d4082fc6ad2214e945b5b7368b828fb16e9a9;p=cascardo%2Flinux.git

diff --git a/kernel/panic.c b/kernel/panic.c
index fa400852bf6c..535c96510a44 100644
--- a/kernel/panic.c
+++ b/kernel/panic.c
@@ -73,6 +73,26 @@ void __weak nmi_panic_self_stop(struct pt_regs *regs)
 
 atomic_t panic_cpu = ATOMIC_INIT(PANIC_CPU_INVALID);
 
+/*
+ * A variant of panic() called from NMI context. We return if we've already
+ * panicked on this CPU. If another CPU already panicked, loop in
+ * nmi_panic_self_stop() which can provide architecture dependent code such
+ * as saving register state for crash dump.
+ */
+void nmi_panic(struct pt_regs *regs, const char *msg)
+{
+	int old_cpu, cpu;
+
+	cpu = raw_smp_processor_id();
+	old_cpu = atomic_cmpxchg(&panic_cpu, PANIC_CPU_INVALID, cpu);
+
+	if (old_cpu == PANIC_CPU_INVALID)
+		panic("%s", msg);
+	else if (old_cpu != cpu)
+		nmi_panic_self_stop(regs);
+}
+EXPORT_SYMBOL(nmi_panic);
+
 /**
  *	panic - halt the system
  *	@fmt: The text string to print