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

[Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>]

On 09:43 Fri 24 Sep     , Sascha Hauer wrote:
> On Fri, Sep 24, 2010 at 12:00:42AM -0700, Andre wrote:
> > 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.
> 
> Indeed. We have get_unaligned_be32() / put_unaligned_be32(). These should be
> the correct functions, right?
no-nned IIRC as be32_to_cpu and cpu_to_be32 already handle this
depending on the arch

Best Regards,
J.

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