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authorWang Nan <wangnan0@huawei.com>2015-02-10 04:34:05 +0300
committerIngo Molnar <mingo@kernel.org>2015-02-18 23:50:12 +0300
commitb7e37567d080301d38a302bb93ba79d1ca446dca (patch)
tree88fa4b505c504dcd75a80c4ed24df03804329c2c /arch/x86/kernel/kprobes
parent5154d4f2adfdabe5aeb247e5b2b6b10fae5f6d50 (diff)
downloadlinux-b7e37567d080301d38a302bb93ba79d1ca446dca.tar.xz
kprobes/x86: Mark 2 bytes NOP as boostable
Currently, x86 kprobes is unable to boost 2 bytes nop like: nopl 0x0(%rax,%rax,1) which is 0x0f 0x1f 0x44 0x00 0x00. Such nops have exactly 5 bytes to hold a relative jmp instruction. Boosting them should be obviously safe. This patch enable boosting such nops by simply updating twobyte_is_boostable[] array. Signed-off-by: Wang Nan <wangnan0@huawei.com> Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: <lizefan@huawei.com> Link: http://lkml.kernel.org/r/1423532045-41049-1-git-send-email-wangnan0@huawei.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/kernel/kprobes')
-rw-r--r--arch/x86/kernel/kprobes/core.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c
index 98f654d466e5..6a1146ea4d4d 100644
--- a/arch/x86/kernel/kprobes/core.c
+++ b/arch/x86/kernel/kprobes/core.c
@@ -84,7 +84,7 @@ static volatile u32 twobyte_is_boostable[256 / 32] = {
/* 0 1 2 3 4 5 6 7 8 9 a b c d e f */
/* ---------------------------------------------- */
W(0x00, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0, 0, 0, 0, 0, 0) | /* 00 */
- W(0x10, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) , /* 10 */
+ W(0x10, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1) , /* 10 */
W(0x20, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) | /* 20 */
W(0x30, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) , /* 30 */
W(0x40, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) | /* 40 */