xen/arm: gic_shutdown_irq must only disable the right IRQ

When GICD_ICENABLERn is read, all the 1s bit represent enabled IRQs.
Currently gic_shutdown_irq:
    - read GICD_ICENABLER
    - set the corresping bit to 1
    - write back the new value
That means, Xen will disable more IRQs than necessary.

Signed-off-by: Julien Grall <julien.grall@linaro.org>
Acked-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>

diff --git a/xen/arch/arm/gic.c b/xen/arch/arm/gic.c
index 177560e3d1f7941cdfbae238422268a9fb6ae02d..cafb68110a8e05ebaa3d2bc8dce5c382b4b81471 100644 (file)
--- a/xen/arch/arm/gic.c
+++ b/xen/arch/arm/gic.c
@@ -117,12 +117,10 @@ static unsigned int gic_irq_startup(struct irq_desc *desc)
 
 static void gic_irq_shutdown(struct irq_desc *desc)
 {
-    uint32_t enabler;
     int irq = desc->irq;
 
     /* Disable routing */
-    enabler = GICD[GICD_ICENABLER + irq / 32];
-    GICD[GICD_ICENABLER + irq / 32] = enabler | (1u << (irq % 32));
+    GICD[GICD_ICENABLER + irq / 32] = (1u << (irq % 32));
 }
 
 static void gic_irq_enable(struct irq_desc *desc)