Messages in this thread | | | From | James Jones <> | Subject | Re: [PATCH] ARM: Fix find_next_zero_bit and related assembly | Date | Tue, 23 Nov 2010 15:28:25 -0800 |
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On Tuesday 23 November 2010 13:26:47 Nicolas Pitre wrote: > On Thu, 11 Nov 2010, James Jones wrote: > > The find_next_bit, find_first_bit, find_next_zero_bit > > and find_first_zero_bit functions were not properly > > clamping to the maxbit argument at the bit level. They > > were instead only checking maxbit at the byte level. > > To fix this, add a compare and a conditional move > > instruction to the end of the common bit-within-the- > > byte code used by all the functions and be sure not to > > clobber the maxbit argument before it is used. > > > > Signed-off-by: James Jones <jajones@nvidia.com> > > Tested-by: Stephen Warren <swarren@nvidia.com> > > Reviewed-by: Nicolas Pitre <nicolas.pitre@linaro.org> > > Please send to RMK's patch system.
Thanks for the review. It's already in the patch system, but I updated the entry to include your reviewed-by line.
-James
> > --- > > > > arch/arm/lib/findbit.S | 6 ++++-- > > 1 files changed, 4 insertions(+), 2 deletions(-) > > > > diff --git a/arch/arm/lib/findbit.S b/arch/arm/lib/findbit.S > > index 1e4cbd4..64f6bc1 100644 > > --- a/arch/arm/lib/findbit.S > > +++ b/arch/arm/lib/findbit.S > > @@ -174,8 +174,8 @@ ENDPROC(_find_next_bit_be) > > > > */ > > > > .L_found: > > #if __LINUX_ARM_ARCH__ >= 5 > > > > - rsb r1, r3, #0 > > - and r3, r3, r1 > > + rsb r0, r3, #0 > > + and r3, r3, r0 > > > > clz r3, r3 > > rsb r3, r3, #31 > > add r0, r2, r3 > > > > @@ -190,5 +190,7 @@ ENDPROC(_find_next_bit_be) > > > > addeq r2, r2, #1 > > mov r0, r2 > > > > #endif > > > > + cmp r1, r0 @ Clamp to maxbit > > + movlo r0, r1 > > > > mov pc, lr
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