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| author | Chuang Wang <nashuiliang@gmail.com> | 2022-11-29 11:39:51 +0300 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2023-01-10 14:37:14 +0300 |
| commit | 9fcad995c6c52cc9791f7ee9f1386a5684055f9c (patch) | |
| tree | 59debf93ae4d59458c437d624b16ac4da9d78d7f /arch/x86/kernel/kprobes | |
| parent | 7bdb1767bf011c7f6065ac483ad2f00e434c3979 (diff) | |
| download | linux-9fcad995c6c52cc9791f7ee9f1386a5684055f9c.tar.xz | |
x86/kprobes: Use switch-case for 0xFF opcodes in prepare_emulation
For the `FF /digit` opcodes in prepare_emulation, use switch-case
instead of hand-written code to make the logic easier to understand.
Signed-off-by: Chuang Wang <nashuiliang@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Link: https://lore.kernel.org/r/20221129084022.718355-1-nashuiliang@gmail.com
Diffstat (limited to 'arch/x86/kernel/kprobes')
| -rw-r--r-- | arch/x86/kernel/kprobes/core.c | 20 |
1 files changed, 11 insertions, 9 deletions
diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c index 33390ed4dcf3..fd0420a3e72e 100644 --- a/arch/x86/kernel/kprobes/core.c +++ b/arch/x86/kernel/kprobes/core.c @@ -655,17 +655,19 @@ static int prepare_emulation(struct kprobe *p, struct insn *insn) * is determined by the MOD/RM byte. */ opcode = insn->modrm.bytes[0]; - if ((opcode & 0x30) == 0x10) { - if ((opcode & 0x8) == 0x8) - return -EOPNOTSUPP; /* far call */ - /* call absolute, indirect */ + switch (X86_MODRM_REG(opcode)) { + case 0b010: /* FF /2, call near, absolute indirect */ p->ainsn.emulate_op = kprobe_emulate_call_indirect; - } else if ((opcode & 0x30) == 0x20) { - if ((opcode & 0x8) == 0x8) - return -EOPNOTSUPP; /* far jmp */ - /* jmp near absolute indirect */ + break; + case 0b100: /* FF /4, jmp near, absolute indirect */ p->ainsn.emulate_op = kprobe_emulate_jmp_indirect; - } else + break; + case 0b011: /* FF /3, call far, absolute indirect */ + case 0b101: /* FF /5, jmp far, absolute indirect */ + return -EOPNOTSUPP; + } + + if (!p->ainsn.emulate_op) break; if (insn->addr_bytes != sizeof(unsigned long)) |