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

From: Sascha Hauer <s.hauer@pengutronix.de>
To: Andre <armccurdy@gmail.com>
Cc: barebox@lists.infradead.org
Subject: Re: [PATCH 2/2] sha1/sha256: use be32_to_cpu and cpu_to_be32
Date: Fri, 24 Sep 2010 09:43:03 +0200	[thread overview]
Message-ID: <20100924074303.GO23406@pengutronix.de> (raw)
In-Reply-To: <4C9C4C9A.7010504@gmail.com>

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?

Sascha

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