From ec3c90f3c8aea103d8a2789caffdea652a3cfda0 Mon Sep 17 00:00:00 2001 From: Nathan Whitehorn Date: Tue, 9 Mar 2010 02:00:53 +0000 Subject: [PATCH] Place interrupt handling in a critical section and remove double counting in incrementing the interrupt nesting level. This fixes a number of bugs in which the interrupt thread could be preempted by an IPI, indefinitely delaying acknowledgement of the interrupt to the PIC, causing interrupt starvation and hangs. Reported by: linimon Reviewed by: marcel, jhb MFC after: 1 week --- sys/powerpc/aim/interrupt.c | 6 ++++-- sys/powerpc/booke/interrupt.c | 8 ++++---- 2 files changed, 8 insertions(+), 6 deletions(-) diff --git a/sys/powerpc/aim/interrupt.c b/sys/powerpc/aim/interrupt.c index d7f489ad4e2..b4360384155 100644 --- a/sys/powerpc/aim/interrupt.c +++ b/sys/powerpc/aim/interrupt.c @@ -80,15 +80,17 @@ powerpc_interrupt(struct trapframe *framep) switch (framep->exc) { case EXC_EXI: - atomic_add_int(&td->td_intr_nesting_level, 1); + critical_enter(); PIC_DISPATCH(pic, framep); - atomic_subtract_int(&td->td_intr_nesting_level, 1); + critical_exit(); break; case EXC_DECR: + critical_enter(); atomic_add_int(&td->td_intr_nesting_level, 1); decr_intr(framep); atomic_subtract_int(&td->td_intr_nesting_level, 1); + critical_exit(); break; default: diff --git a/sys/powerpc/booke/interrupt.c b/sys/powerpc/booke/interrupt.c index 01ee3d9fa83..2367bf94b33 100644 --- a/sys/powerpc/booke/interrupt.c +++ b/sys/powerpc/booke/interrupt.c @@ -118,9 +118,11 @@ powerpc_decr_interrupt(struct trapframe *framep) struct thread *td; td = PCPU_GET(curthread); + critical_enter(); atomic_add_int(&td->td_intr_nesting_level, 1); decr_intr(framep); atomic_subtract_int(&td->td_intr_nesting_level, 1); + critical_exit(); } /* @@ -129,10 +131,8 @@ powerpc_decr_interrupt(struct trapframe *framep) void powerpc_extr_interrupt(struct trapframe *framep) { - struct thread *td; - td = PCPU_GET(curthread); - atomic_add_int(&td->td_intr_nesting_level, 1); + critical_enter(); PIC_DISPATCH(pic, framep); - atomic_subtract_int(&td->td_intr_nesting_level, 1); + critical_exit(); }