From: James Jones Date: Tue, 23 Nov 2010 23:21:37 +0000 (+0100) Subject: ARM: 6482/2: Fix find_next_zero_bit and related assembly X-Git-Tag: firefly_0821_release~7613^2~3354^2 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=0e91ec0c06d2cd15071a6021c94840a50e6671aa;p=firefly-linux-kernel-4.4.55.git ARM: 6482/2: Fix find_next_zero_bit and related assembly 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. Cc: Reviewed-by: Nicolas Pitre Tested-by: Stephen Warren Signed-off-by: James Jones Signed-off-by: Russell King --- diff --git a/arch/arm/lib/findbit.S b/arch/arm/lib/findbit.S index 1e4cbd4e7be9..64f6bc1a9132 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