From f8b435bb918412c9410da4c4b0b02b6b3d99b27c Mon Sep 17 00:00:00 2001 From: Rabin Vincent Date: Wed, 4 Jul 2012 07:37:37 +0100 Subject: [PATCH] ARM: 7440/1: kprobes: only test 'sub pc, pc, #1b-2b+8-2' on ARMv6 'sub pc, pc, #1b-2b+8-2' results in address<1:0> == '10'. sub pc, pc, #const (== ADR pc, #const) performs an interworking branch (BXWritePC()) on ARMv7+ and a simple branch (BranchWritePC()) on earlier versions. In ARM state, BXWritePC() is UNPREDICTABLE when address<1:0> == '10'. In ARM state on ARMv6+, BranchWritePC() ignores address<1:0>. Before ARMv6, BranchWritePC() is UNPREDICTABLE if address<1:0> != '00' So the instruction is UNPREDICTABLE both before and after v6. Acked-by: Jon Medhurst Signed-off-by: Rabin Vincent Signed-off-by: Russell King --- arch/arm/kernel/kprobes-test-arm.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/arm/kernel/kprobes-test-arm.c b/arch/arm/kernel/kprobes-test-arm.c index ba32b393b3f0..38c1a3b103a0 100644 --- a/arch/arm/kernel/kprobes-test-arm.c +++ b/arch/arm/kernel/kprobes-test-arm.c @@ -187,8 +187,8 @@ void kprobe_arm_test_cases(void) TEST_BF_R ("mov pc, r",0,2f,"") TEST_BF_RR("mov pc, r",0,2f,", asl r",1,0,"") TEST_BB( "sub pc, pc, #1b-2b+8") -#if __LINUX_ARM_ARCH__ >= 6 - TEST_BB( "sub pc, pc, #1b-2b+8-2") /* UNPREDICTABLE before ARMv6 */ +#if __LINUX_ARM_ARCH__ == 6 && !defined(CONFIG_CPU_V7) + TEST_BB( "sub pc, pc, #1b-2b+8-2") /* UNPREDICTABLE before and after ARMv6 */ #endif TEST_BB_R( "sub pc, pc, r",14, 1f-2f+8,"") TEST_BB_R( "rsb pc, r",14,1f-2f+8,", pc") -- 2.39.5