[Xen-changelog] [xen master] xen/arm: gic: Document how gic_set_irq_type should be called

[patchbot@xxxxxxx]

commit 84e8aaa5a0cd59f774cada9b04fb6db4512f8692
Author:     Julien Grall <julien.grall@xxxxxxx>
AuthorDate: Wed Jul 27 14:58:26 2016 +0100
Commit:     Stefano Stabellini <sstabellini@xxxxxxxxxx>
CommitDate: Wed Jul 27 12:23:35 2016 -0700

    xen/arm: gic: Document how gic_set_irq_type should be called
    
    Changing the value of Int_config is UNPREDICTABLE when the corresponding
    interrupt is not disabled.
    
    The driver is assuming the interrupt will be disabled by the caller of
    gic_set_irq_type. Add an ASSERT to ensure it.
    
    Signed-off-by: Julien Grall <julien.grall@xxxxxxx>
    Acked-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>
---
 xen/arch/arm/gic.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/xen/arch/arm/gic.c b/xen/arch/arm/gic.c
index b9371a7..72bb885 100644
--- a/xen/arch/arm/gic.c
+++ b/xen/arch/arm/gic.c
@@ -96,8 +96,14 @@ void gic_restore_state(struct vcpu *v)
     gic_restore_pending_irqs(v);
 }
 
+/* desc->irq needs to be disabled before calling this function */
 static void gic_set_irq_type(struct irq_desc *desc, unsigned int type)
 {
+    /*
+     * IRQ must be disabled before configuring it (see 4.3.13 in ARM IHI
+     * 0048B.b). We rely on the caller to do it.
+     */
+    ASSERT(test_bit(_IRQ_DISABLED, &desc->status));
     ASSERT(spin_is_locked(&desc->lock));
     ASSERT(type != IRQ_TYPE_INVALID);
 
--
generated by git-patchbot for /home/xen/git/xen.git#master

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