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[PATCH] xen/arm: vgic: Add missing 'U' in VGIC_ICFG_MASK for shifted constant



With UBSAN on some arm64 platforms, e.g. FVP_Base_RevC-2xAEMvA, the
following splat will be printed while Dom0 is booting:
```
(XEN) ==================================================================
(XEN) UBSAN: Undefined behaviour in arch/arm/vgic.c:372:15
(XEN) left shift of 1 by 31 places cannot be represented in type 'int'
(XEN) Xen WARN at common/ubsan/ubsan.c:172
(XEN) ----[ Xen-4.18-unstable  arm64  debug=y ubsan=y  Not tainted ]----
```

This is because there is a device node in the device tree with 0xf
as the interrupts property. Example of the device tree node is shown
below:
```
ethernet@202000000 {
    compatible = "smsc,lan91c111";
    reg = <0x2 0x2000000 0x10000>;
    interrupts = <0xf>;
};
```
and this value is passed to vgic_get_virq_type() as "index" then "intr"
in VGIC_ICFG_MASK.

Add the missing 'U' in VGIC_ICFG_MASK as a fix, and this should also
addressing MISRA Rule 7.2:

    A "u" or "U" suffix shall be applied to all integer constants that
    are represented in an unsigned type

Signed-off-by: Henry Wang <Henry.Wang@xxxxxxx>
---
This patch should be based on top of Julien's series
"xen/arm: Enable UBSAN support" to test.
---
 xen/arch/arm/vgic.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/xen/arch/arm/vgic.c b/xen/arch/arm/vgic.c
index c61c68870c..97d6f61066 100644
--- a/xen/arch/arm/vgic.c
+++ b/xen/arch/arm/vgic.c
@@ -358,7 +358,7 @@ void vgic_disable_irqs(struct vcpu *v, uint32_t r, int n)
     }
 }
 
-#define VGIC_ICFG_MASK(intr) (1 << ((2 * ((intr) % 16)) + 1))
+#define VGIC_ICFG_MASK(intr) (1U << ((2 * ((intr) % 16)) + 1))
 
 /* The function should be called with the rank lock taken */
 static inline unsigned int vgic_get_virq_type(struct vcpu *v, int n, int index)
-- 
2.25.1




 


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