Commit acb1feab authored Nov 17, 2017 by Nicholas Piggin Committed by Michael Ellerman Dec 11, 2017

powerpc/64: Don't trace irqs-off at interrupt return to soft-disabled context

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.

Fixes: 7c0482e3 ("powerpc/irq: Fix another case of lazy IRQ state getting out of sync")
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

parent 7813043e

arch/powerpc/kernel/entry_64.S

+7 −3

Original line number	Diff line number	Diff line
		@@ -911,9 +911,13 @@ END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR)
		beq 1f
		rlwinm r7,r7,0,~PACA_IRQ_HARD_DIS
		stb r7,PACAIRQHAPPENED(r13)
		1: li r0,0
		stb r0,PACASOFTIRQEN(r13);
		TRACE_DISABLE_INTS
		1:
		#if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_BUG)
		/* The interrupt should not have soft enabled. */
		lbz r7,PACASOFTIRQEN(r13)
		1: tdnei r7,0
		EMIT_BUG_ENTRY 1b,__FILE__,__LINE__,BUGFLAG_WARNING
		#endif
		b .Ldo_restore

		/*

Admin message