[PATCH v2 3/3] powerpc: machine check interrupt is a non-maskable interrupt

[Nicholas Piggin]

Use nmi_enter similarly to system reset interrupts. This uses NMI
printk NMI buffers and turns off various debugging facilities that
helps avoid tripping on ourselves or other CPUs.

Signed-off-by: Nicholas Piggin <npig...@gmail.com>
---
 arch/powerpc/kernel/traps.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c
index 2849c4f50324..6d31f9d7c333 100644
--- a/arch/powerpc/kernel/traps.c
+++ b/arch/powerpc/kernel/traps.c
@@ -789,8 +789,10 @@ int machine_check_generic(struct pt_regs *regs)
 
 void machine_check_exception(struct pt_regs *regs)
 {
-       enum ctx_state prev_state = exception_enter();
        int recover = 0;
+       bool nested = in_nmi();
+       if (!nested)
+               nmi_enter();
 
        __this_cpu_inc(irq_stat.mce_exceptions);
 
@@ -820,10 +822,11 @@ void machine_check_exception(struct pt_regs *regs)
 
        /* Must die if the interrupt is not recoverable */
        if (!(regs->msr & MSR_RI))
-               panic("Unrecoverable Machine check");
+               nmi_panic(regs, "Unrecoverable Machine check");
 
 bail:
-       exception_exit(prev_state);
+       if (!nested)
+               nmi_exit();
 }
 
 void SMIException(struct pt_regs *regs)
-- 
2.11.0