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[v10,01/17] powerpc/64: do not trace irqs-off at interrupt return to soft-disabled context

Message ID 1513742157-28768-2-git-send-email-maddy@linux.vnet.ibm.com
State New
Headers show
Series powerpc: "paca->soft_enabled" based local atomic operation implementation | expand

Commit Message

maddy Dec. 20, 2017, 3:55 a.m. UTC
From: Nicholas Piggin <npiggin@gmail.com>

When an interrupt is returning to a soft-disabled context (which can
happen for non-maskable interrupts or synchronous interrupts), it goes
through the motions of soft-disabling again, including calling
TRACE_DISABLE_INTS (i.e., trace_hardirqs_off()).

This is not necessary, because we must already be soft-disabled in the
interrupt context, it also may be causing crashes in the irq tracing
code to re-enter as an nmi. Replace it with a warning to ensure that
soft-interrupts are still disabled.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
 arch/powerpc/kernel/entry_64.S | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)
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diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S
index 3320bcac7192..b3055ebf20d1 100644
--- a/arch/powerpc/kernel/entry_64.S
+++ b/arch/powerpc/kernel/entry_64.S
@@ -911,9 +911,13 @@  END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR)
 	beq	1f
 	rlwinm	r7,r7,0,~PACA_IRQ_HARD_DIS
-1:	li	r0,0
-	stb	r0,PACASOFTIRQEN(r13);
+#if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_BUG)
+	/* The interrupt should not have soft enabled. */
+	lbz	r7,PACASOFTIRQEN(r13)
+	tdnei	r7,0
 	b	.Ldo_restore