Re: [PATCH] powerpc/32: fix csum_partial_copy_generic()

Christophe Leroy
2016-08-01T13:46:51Z

Le 01/08/2016 à 15:15, Segher Boessenkool a écrit :
> On Mon, Aug 01, 2016 at 02:56:05PM +0200, Christophe Leroy wrote:
>> --- a/arch/powerpc/lib/checksum_32.S
>> +++ b/arch/powerpc/lib/checksum_32.S
>> @@ -127,7 +127,8 @@ _GLOBAL(csum_partial_copy_generic)
>> stw r7,12(r1)
>> stw r8,8(r1)
>>
>> - andi. r0,r4,1 /* is destination address even ? */
>> + rlwinm r0,r4,3,0x8 /* is destination address even ? */
>> + rlwnm r6,r6,r0,0,31 /* swap bytes for odd destination */
>> cmplwi cr7,r0,0
>> addic r12,r6,0
>> addi r6,r4,-4
>
> That does not "swap bytes"; it shifts the word up by 8 bits, instead.
> That may or may not do what is intended.
>

Indeed it does what is intended, similar to what is done at the end of
the function:

...
beqlr+ cr7
rlwinm r3,r3,8,0,31 /* swap bytes for odd destination */
blr

Should I fix the (both) comment(s) ?

Christophe