From mboxrd@z Thu Jan 1 00:00:00 1970 From: dave.martin@linaro.org (Dave Martin) Date: Wed, 2 Feb 2011 18:53:44 +0000 Subject: [PATCH] ARM: bitops: Fix low-level code to be Thumb-2 compatible Message-ID: <1296672824-22743-1-git-send-email-dave.martin@linaro.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org The new bitops code cunningly str , [r1, -r1] to trigger a fault by attempting to store to address zero. This code doesn't assemble in Thumb-2, since Thumb-2 doesn't allow negative register offsets at all for loads and stores. The patch loads 0 into r2 and uses that as a base register instead for the Thumb-2 case: r2 seems non-live at every instance of this problem. The ARM case is unaffected. Signed-off-by: Dave Martin --- arch/arm/lib/bitops.h | 16 ++++++++++++---- 1 files changed, 12 insertions(+), 4 deletions(-) diff --git a/arch/arm/lib/bitops.h b/arch/arm/lib/bitops.h index f8a2bd3..87d6b17 100644 --- a/arch/arm/lib/bitops.h +++ b/arch/arm/lib/bitops.h @@ -1,7 +1,9 @@ #if __LINUX_ARM_ARCH__ >= 6 .macro bitop, instr tst r1, #3 - strne r1, [r1, -r1] @ assert word-aligned + ARM( strne r1, [r1, -r1] ) @ assert word-aligned + THUMB( movne r2, #0 ) + THUMB( strne r1, [r2] ) mov r2, #1 and r3, r0, #31 @ Get bit offset mov r0, r0, lsr #5 @@ -17,7 +19,9 @@ .macro testop, instr, store tst r1, #3 - strne r1, [r1, -r1] @ assert word-aligned + ARM( strne r1, [r1, -r1] ) @ assert word-aligned + THUMB( movne r2, #0 ) + THUMB( strne r1, [r2] ) mov r2, #1 and r3, r0, #31 @ Get bit offset mov r0, r0, lsr #5 @@ -38,7 +42,9 @@ #else .macro bitop, instr tst r1, #3 - strne r1, [r1, -r1] @ assert word-aligned + ARM( strne r1, [r1, -r1] ) @ assert word-aligned + THUMB( movne r2, #0 ) + THUMB( strne r1, [r2] ) and r2, r0, #31 mov r0, r0, lsr #5 mov r3, #1 @@ -61,7 +67,9 @@ */ .macro testop, instr, store tst r1, #3 - strne r1, [r1, -r1] @ assert word-aligned + ARM( strne r1, [r1, -r1] ) @ assert word-aligned + THUMB( movne r2, #0 ) + THUMB( strne r1, [r2] ) and r3, r0, #31 mov r0, r0, lsr #5 save_and_disable_irqs ip -- 1.7.1