Re: [XEN v1 2/9] xen/arm: Define translate_dt_address_size() for the translation between u64 and paddr_t

[Julien Grall <julien@xxxxxxx>]

Hi Ayan,

On 15/12/2022 19:32, Ayan Kumar Halder wrote:
> paddr_t may be u64 or u32 depending of the type of architecture.
> Thus, while translating between u64 and paddr_t, one should check that the
> truncated bits are 0. If not, then raise an appropriate error.
I am not entirely convinced this extra helper is worth it. If the user 
can't provide 32-bit address in the DT, then there are also a lot of 
other part that can go wrong.
Bertrand, Stefano, what do you think?

> Signed-off-by: Ayan Kumar Halder <ayan.kumar.halder@xxxxxxx>
> ---
>   xen/arch/arm/include/asm/platform.h | 26 ++++++++++++++++++++++++++
>   1 file changed, 26 insertions(+)
>
> diff --git a/xen/arch/arm/include/asm/platform.h 
> b/xen/arch/arm/include/asm/platform.h
> index 997eb25216..6be1549f09 100644
> --- a/xen/arch/arm/include/asm/platform.h
> +++ b/xen/arch/arm/include/asm/platform.h
> @@ -42,6 +42,32 @@ struct platform_desc {
>       unsigned int dma_bitsize;
>   };
>   
> +static inline int translate_dt_address_size(u64 *dt_addr, u64 *dt_size,
> +                                            paddr_t *addr, paddr_t *size)
> +{
> +#ifdef CONFIG_ARM_PA_32
This is not yet defined. So you want to mention it in the commit message.

> +    if ( dt_addr && (*dt_addr >> PADDR_SHIFT) )
> +    {
> +        dprintk(XENLOG_ERR, "Error in DT. Invalid address\n");
> +        return -ENXIO;
> +    }
> +
> +    if ( dt_size && (*dt_size >> PADDR_SHIFT) )
> +    {
> +        dprintk(XENLOG_ERR, "Error in DT. Invalid size\n");
> +        return -ENXIO;
> +    }
> +#endif
> +
> +    if ( dt_addr && addr )
> +        *addr = (paddr_t) (*dt_addr);
> +
> +    if ( dt_size && size )
> +        *size = (paddr_t) (*dt_size);
> +
> +    return 0;
> +}
> +
>   /*
>    * Quirk for platforms where device tree incorrectly reports 4K GICC
>    * size, but actually the two GICC register ranges are placed at 64K
Cheers,

--
Julien Grall