[Xen-changelog] [xen master] xen/arm: Disable interrupts for the entire duration of the context switch

[patchbot@xxxxxxx]

commit 9f5179a4ecafd9a15e0a066e0f935ded681bf997
Author:     Jaeyong Yoo <jaeyong.yoo@xxxxxxxxxxx>
AuthorDate: Wed May 22 02:34:18 2013 +0000
Commit:     Ian Campbell <ian.campbell@xxxxxxxxxx>
CommitDate: Thu May 23 12:51:51 2013 +0100

    xen/arm: Disable interrupts for the entire duration of the context switch
    
    Not just while saving state. Otherwise there is a race between interrupts
    arriving and updating the LR state and gic_restore_state overwriting them 
with
    the saved state.
    
    With this change we no longer need to disable interrupts in 
gic_restore_state.
    
    Signed-off-by: Jaeyong Yoo <jaeyong.yoo@xxxxxxxxxxx>
    Acked-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
    [ ijc -- rewrote commit message ]
---
 xen/arch/arm/domain.c |    4 ++--
 xen/arch/arm/gic.c    |    2 --
 2 files changed, 2 insertions(+), 4 deletions(-)

diff --git a/xen/arch/arm/domain.c b/xen/arch/arm/domain.c
index 9ca44ea..ee12b5f 100644
--- a/xen/arch/arm/domain.c
+++ b/xen/arch/arm/domain.c
@@ -226,10 +226,10 @@ static void schedule_tail(struct vcpu *prev)
 {
     ctxt_switch_from(prev);
 
-    local_irq_enable();
-
     ctxt_switch_to(current);
 
+    local_irq_enable();
+
     if ( prev != current )
         update_runstate_area(current);
 }
diff --git a/xen/arch/arm/gic.c b/xen/arch/arm/gic.c
index 30bf8d1..d9940ea 100644
--- a/xen/arch/arm/gic.c
+++ b/xen/arch/arm/gic.c
@@ -93,11 +93,9 @@ void gic_restore_state(struct vcpu *v)
     if ( is_idle_vcpu(v) )
         return;
 
-    spin_lock_irq(&gic.lock);
     this_cpu(lr_mask) = v->arch.lr_mask;
     for ( i=0; i<nr_lrs; i++)
         GICH[GICH_LR + i] = v->arch.gic_lr[i];
-    spin_unlock_irq(&gic.lock);
     GICH[GICH_APR] = v->arch.gic_apr;
     GICH[GICH_HCR] = GICH_HCR_EN;
     isb();
--
generated by git-patchbot for /home/xen/git/xen.git#master

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