[PATCH v6 21/24] arm64: Handle serror in NMI context

From: Julien Thierry
Date: Mon Nov 12 2018 - 06:58:17 EST


Per definition of the daifflags, Serrors can occur during any interrupt
context, that includes NMI contexts. Trying to nmi_enter in an nmi context
will crash.

Skip nmi_enter/nmi_exit when serror occurred during an NMI.

Suggested-by: James Morse <james.morse@xxxxxxx>
Signed-off-by: Julien Thierry <julien.thierry@xxxxxxx>
Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: Will Deacon <will.deacon@xxxxxxx>
Cc: Mark Rutland <mark.rutland@xxxxxxx>
Cc: Dave Martin <dave.martin@xxxxxxx>
Cc: James Morse <james.morse@xxxxxxx>
---
arch/arm64/kernel/traps.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c
index 5f4d9ac..66344cd 100644
--- a/arch/arm64/kernel/traps.c
+++ b/arch/arm64/kernel/traps.c
@@ -897,13 +897,17 @@ bool arm64_is_fatal_ras_serror(struct pt_regs *regs, unsigned int esr)

asmlinkage void do_serror(struct pt_regs *regs, unsigned int esr)
{
- nmi_enter();
+ const bool was_in_nmi = in_nmi();
+
+ if (!was_in_nmi)
+ nmi_enter();

/* non-RAS errors are not containable */
if (!arm64_is_ras_serror(esr) || arm64_is_fatal_ras_serror(regs, esr))
arm64_serror_panic(regs, esr);

- nmi_exit();
+ if (!was_in_nmi)
+ nmi_exit();
}

void __pte_error(const char *file, int line, unsigned long val)
--
1.9.1