[PATCH] arm64: mm: use ubfm for dcache_line_size

Will Deacon will.deacon at arm.com
Fri Jan 17 07:24:00 EST 2014


On Fri, Jan 17, 2014 at 11:22:27AM +0000, Ard Biesheuvel wrote:
> On 17 January 2014 09:04, Jingoo Han <jg1.han at samsung.com> wrote:
> > Use 'ubfm' for the bitfield move instruction; thus, single
> > instruction can be used instead of two instructions, when
> > getting the minimum D-cache line size from CTR_EL0 register.
> >
> > Signed-off-by: Jingoo Han <jg1.han at samsung.com>
> > ---
> >  arch/arm64/mm/proc-macros.S |    3 +--
> >  1 file changed, 1 insertion(+), 2 deletions(-)
> >
> > diff --git a/arch/arm64/mm/proc-macros.S b/arch/arm64/mm/proc-macros.S
> > index 8957b82..c31f41e 100644
> > --- a/arch/arm64/mm/proc-macros.S
> > +++ b/arch/arm64/mm/proc-macros.S
> > @@ -38,8 +38,7 @@
> >   */
> >         .macro  dcache_line_size, reg, tmp
> >         mrs     \tmp, ctr_el0                   // read CTR
> > -       lsr     \tmp, \tmp, #16
> > -       and     \tmp, \tmp, #0xf                // cache line size encoding
> > +       ubfm    \tmp, \tmp, #0x16, 0x19         // cache line size encoding
> 
> Even if the # is optional for immediates these days, perhaps it is
> better to adhere to a single style in one line?

In ARM assembler syntax, the preferred prefix for decimal immediates is '#'
not 0x ;)

Will



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