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-Url: https://rtime.felk.cvut.cz/gitweb/lisovros/linux_canprio.git/commitdiff_plain/5dc21210d51aaf6db74c91c31b4e4f4f57a7691d ARM: 6482/2: Fix find_next_zero_bit and related assembly commit 0e91ec0c06d2cd15071a6021c94840a50e6671aa upstream. 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. Reviewed-by: Nicolas Pitre Tested-by: Stephen Warren Signed-off-by: James Jones Signed-off-by: Russell King Signed-off-by: Greg Kroah-Hartman --- diff --git a/arch/arm/lib/findbit.S b/arch/arm/lib/findbit.S index 1e4cbd4e7be..64f6bc1a913 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