Since Grp5 far indirect JMP is FF "mod 101 r/m", it should be
(modrm & 0x38) == 0x28, and near indirect JMP is also 0x38 == 0x20.
So we can mask modrm with 0x30 and check 0x20.
This is actually what the original code does, it also doesn't care
the last bit. So the result code is same.
Thus, I think this is just a cosmetic cleanup.
Signed-off-by: Masami Hiramatsu <mhira...@kernel.org>
---
arch/x86/kernel/kprobes/core.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c
index 08674e7a5d7b..be76568d57a5 100644
--- a/arch/x86/kernel/kprobes/core.c
+++ b/arch/x86/kernel/kprobes/core.c
@@ -462,8 +462,7 @@ static void set_resume_flags(struct kprobe *p, struct insn
*insn)
p->ainsn.is_call = 1;
p->ainsn.is_abs_ip = 1;
break;
- } else if (((opcode & 0x31) == 0x20) ||
- ((opcode & 0x31) == 0x21)) {
+ } else if ((opcode & 0x30) == 0x20) {
/*
* jmp near and far, absolute indirect
* ip is correct.
