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

[Christophe Leroy]

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