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Subject[PATCH v10 24/25] arm64: Skip irqflags tracing for NMI in IRQs disabled context
Date
When an NMI is raised while interrupts where disabled, the IRQ tracing
already is in the correct state (i.e. hardirqs_off) and should be left
as such when returning to the interrupted context.

Check whether PMR was masking interrupts when the NMI was raised and
skip IRQ tracing if necessary.

Signed-off-by: Julien Thierry <julien.thierry@arm.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
---
arch/arm64/kernel/entry.S | 21 +++++++++++++++++++++
1 file changed, 21 insertions(+)

diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S
index acf1250..e2251bb 100644
--- a/arch/arm64/kernel/entry.S
+++ b/arch/arm64/kernel/entry.S
@@ -617,7 +617,18 @@ el1_irq:
kernel_entry 1
enable_da_f
#ifdef CONFIG_TRACE_IRQFLAGS
+#ifdef CONFIG_ARM64_PSEUDO_NMI
+alternative_if ARM64_HAS_IRQ_PRIO_MASKING
+ ldr x20, [sp, #S_PMR_SAVE]
+alternative_else
+ mov x20, #GIC_PRIO_IRQON
+alternative_endif
+ cmp x20, #GIC_PRIO_IRQOFF
+ /* Irqs were disabled, don't trace */
+ b.ls 1f
+#endif
bl trace_hardirqs_off
+1:
#endif

irq_handler
@@ -637,8 +648,18 @@ alternative_else_nop_endif
1:
#endif
#ifdef CONFIG_TRACE_IRQFLAGS
+#ifdef CONFIG_ARM64_PSEUDO_NMI
+ /*
+ * if IRQs were disabled when we received the interrupt, we have an NMI
+ * and we are not re-enabling interrupt upon eret. Skip tracing.
+ */
+ cmp x20, #GIC_PRIO_IRQOFF
+ b.ls 1f
+#endif
bl trace_hardirqs_on
+1:
#endif
+
kernel_exit 1
ENDPROC(el1_irq)

--
1.9.1
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