Re: [PATCH] iommu/arm: ipmmu-vmsa: Use 1U << 31 rather than 1 << 31

[Stefano Stabellini <sstabellini@xxxxxxxxxx>]

On Mon, 11 Jan 2021, Oleksandr Tyshchenko wrote:
> From: Oleksandr Tyshchenko <oleksandr_tyshchenko@xxxxxxxx>
> 
> Replace all the use of 1 << 31 with 1U << 31 to prevent undefined
> behavior in the IPMMU-VMSA driver.
> 
> Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@xxxxxxxx>

Reviewed-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>


> ---
> This is a follow-up to
> https://patchew.org/Xen/20201224152419.22453-1-julien@xxxxxxx/
> ---
>  xen/drivers/passthrough/arm/ipmmu-vmsa.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/xen/drivers/passthrough/arm/ipmmu-vmsa.c 
> b/xen/drivers/passthrough/arm/ipmmu-vmsa.c
> index 346165c..aef358d 100644
> --- a/xen/drivers/passthrough/arm/ipmmu-vmsa.c
> +++ b/xen/drivers/passthrough/arm/ipmmu-vmsa.c
> @@ -187,7 +187,7 @@ static DEFINE_SPINLOCK(ipmmu_devices_lock);
>  #define IMCAAR               0x0004
>  
>  #define IMTTBCR                        0x0008
> -#define IMTTBCR_EAE                    (1 << 31)
> +#define IMTTBCR_EAE                    (1U << 31)
>  #define IMTTBCR_PMB                    (1 << 30)
>  #define IMTTBCR_SH1_NON_SHAREABLE      (0 << 28)
>  #define IMTTBCR_SH1_OUTER_SHAREABLE    (2 << 28)
> @@ -251,7 +251,7 @@ static DEFINE_SPINLOCK(ipmmu_devices_lock);
>  #define IMUCTR(n)              ((n) < 32 ? IMUCTR0(n) : IMUCTR32(n))
>  #define IMUCTR0(n)             (0x0300 + ((n) * 16))
>  #define IMUCTR32(n)            (0x0600 + (((n) - 32) * 16))
> -#define IMUCTR_FIXADDEN        (1 << 31)
> +#define IMUCTR_FIXADDEN        (1U << 31)
>  #define IMUCTR_FIXADD_MASK     (0xff << 16)
>  #define IMUCTR_FIXADD_SHIFT    16
>  #define IMUCTR_TTSEL_MMU(n)    ((n) << 4)
> -- 
> 2.7.4
>