Re: [PATCH 1/3] xen/lzo: Implement COPY{4,8} using memcpy()

[Stefano Stabellini <sstabellini@xxxxxxxxxx>]

On Tue, 21 May 2024, Andrew Cooper wrote:
> This is simpler and easier for both humans and compilers to read.
> 
> It also addresses 6 instances of MISRA R5.3 violation (shadowing of the ptr_
> local variable inside both {put,get}_unaligned()).
> 
> No change, not even in the compiled binary.
> 
> Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>

Reviewed-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>


> ---
> CC: George Dunlap <George.Dunlap@xxxxxxxxxx>
> CC: Jan Beulich <JBeulich@xxxxxxxx>
> CC: Stefano Stabellini <sstabellini@xxxxxxxxxx>
> CC: Julien Grall <julien@xxxxxxx>
> CC: Roberto Bagnara <roberto.bagnara@xxxxxxxxxxx>
> CC: consulting@xxxxxxxxxxx <consulting@xxxxxxxxxxx>
> CC: Oleksii Kurochko <oleksii.kurochko@xxxxxxxxx>
> ---
>  xen/common/lzo.c | 11 ++---------
>  1 file changed, 2 insertions(+), 9 deletions(-)
> 
> diff --git a/xen/common/lzo.c b/xen/common/lzo.c
> index cc03f0f5547f..3454ce4a7e24 100644
> --- a/xen/common/lzo.c
> +++ b/xen/common/lzo.c
> @@ -25,15 +25,8 @@
>   */
>  
>  
> -#define COPY4(dst, src)    \
> -        put_unaligned(get_unaligned((const u32 *)(src)), (u32 *)(dst))
> -#if defined(__x86_64__)
> -#define COPY8(dst, src)    \
> -        put_unaligned(get_unaligned((const u64 *)(src)), (u64 *)(dst))
> -#else
> -#define COPY8(dst, src)    \
> -        COPY4(dst, src); COPY4((dst) + 4, (src) + 4)
> -#endif
> +#define COPY4(dst, src) memcpy(dst, src, 4)
> +#define COPY8(dst, src) memcpy(dst, src, 8)
>  
>  #ifdef __MINIOS__
>  # include <lib.h>
> -- 
> 2.30.2
>