Re: [PATCH 2/2] sha1/sha256: use be32_to_cpu and cpu_to_be32

[Andre <armccurdy@gmail.com>]

On 09/21/2010 06:28 AM, Jean-Christophe PLAGNIOL-VILLARD wrote:

> Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD<plagnioj at jcrosoft.com>
> ---
>   lib/sha1.c   |   20 +++-----------------
>   lib/sha256.c |   19 +++----------------
>   2 files changed, 6 insertions(+), 33 deletions(-)
>
> diff --git a/lib/sha1.c b/lib/sha1.c
> index 0e8aed1..b4e2abc 100644
> --- a/lib/sha1.c
> +++ b/lib/sha1.c
> @@ -29,6 +29,7 @@
>   #include<digest.h>
>   #include<init.h>
>   #include<linux/string.h>
> +#include<asm/byteorder.h>
>
>   #define SHA1_SUM_POS	-0x20
>   #define SHA1_SUM_LEN	20
> @@ -44,23 +45,8 @@ sha1_context;
>   /*
>    * 32-bit integer manipulation macros (big endian)
>    */
> -#ifndef GET_UINT32_BE
> -#define GET_UINT32_BE(n,b,i) {				\
> -	(n) = ( (uint32_t) (b)[(i)    ]<<  24 )	\
> -	    | ( (uint32_t) (b)[(i) + 1]<<  16 )	\
> -	    | ( (uint32_t) (b)[(i) + 2]<<   8 )	\
> -	    | ( (uint32_t) (b)[(i) + 3]       );	\
> -}
> -#endif
> -
> -#ifndef PUT_UINT32_BE
> -#define PUT_UINT32_BE(n,b,i) {				\
> -	(b)[(i)    ] = (unsigned char) ( (n)>>  24 );	\
> -	(b)[(i) + 1] = (unsigned char) ( (n)>>  16 );	\
> -	(b)[(i) + 2] = (unsigned char) ( (n)>>   8 );	\
> -	(b)[(i) + 3] = (unsigned char) ( (n)       );	\
> -}
> -#endif
> +#define GET_UINT32_BE(n,b,i) (n) = be32_to_cpu(((uint32_t*)(b))[i / 4])
> +#define PUT_UINT32_BE(n,b,i) ((uint32_t*)(b))[i / 4] = cpu_to_be32(n)
>
>    

The previous macros served two purposes: endian swapping and performing 
the memory accesses byte-by-byte. New versions are unsafe for CPUs which 
do not support misaligned 32bit memory accesses.

Andre
--



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