diff mbox series

[v8,25/26] arm64: Skip irqflags tracing for NMI in IRQs disabled context

Message ID 1546956464-48825-26-git-send-email-julien.thierry@arm.com (mailing list archive)
State New, archived
Headers show
Series arm64: provide pseudo NMI with GICv3 | expand

Commit Message

Julien Thierry Jan. 8, 2019, 2:07 p.m. UTC 
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>
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 mbox series

Patch

diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S
index a0b0a22..bd0b078 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)