diff options
| author | Harvey Harrison <harvey.harrison@gmail.com> | 2008-01-30 13:32:14 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2008-01-30 13:32:14 +0100 |
| commit | 9930927f36ac3e39ffa674dc23ef06f13c39cef7 (patch) | |
| tree | 23c92c361ba87fca19e7d9ffd741b1343b89dcf9 /arch/x86/kernel/kprobes.c | |
| parent | e419190683cdeeda9be69af1dbc77031478559af (diff) | |
| download | lwn-9930927f36ac3e39ffa674dc23ef06f13c39cef7.tar.gz lwn-9930927f36ac3e39ffa674dc23ef06f13c39cef7.zip | |
x86: introduce REX prefix helper for kprobes
Fold some small ifdefs into a helper function.
Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'arch/x86/kernel/kprobes.c')
| -rw-r--r-- | arch/x86/kernel/kprobes.c | 27 |
1 files changed, 19 insertions, 8 deletions
diff --git a/arch/x86/kernel/kprobes.c b/arch/x86/kernel/kprobes.c index 4e33329ce8a3..b1804e40235d 100644 --- a/arch/x86/kernel/kprobes.c +++ b/arch/x86/kernel/kprobes.c @@ -171,6 +171,19 @@ static void __kprobes set_jmp_op(void *from, void *to) } /* + * Check for the REX prefix which can only exist on X86_64 + * X86_32 always returns 0 + */ +static int __kprobes is_REX_prefix(kprobe_opcode_t *insn) +{ +#ifdef CONFIG_X86_64 + if ((*insn & 0xf0) == 0x40) + return 1; +#endif + return 0; +} + +/* * Returns non-zero if opcode is boostable. * RIP relative instructions are adjusted at copying time in 64 bits mode */ @@ -239,14 +252,14 @@ static int __kprobes is_IF_modifier(kprobe_opcode_t *insn) case 0x9d: /* popf/popfd */ return 1; } -#ifdef CONFIG_X86_64 + /* - * on 64 bit x86, 0x40-0x4f are prefixes so we need to look + * on X86_64, 0x40-0x4f are REX prefixes so we need to look * at the next byte instead.. but of course not recurse infinitely */ - if (*insn >= 0x40 && *insn <= 0x4f) + if (is_REX_prefix(insn)) return is_IF_modifier(++insn); -#endif + return 0; } @@ -284,7 +297,7 @@ static void __kprobes fix_riprel(struct kprobe *p) } /* Skip REX instruction prefix. */ - if ((*insn & 0xf0) == 0x40) + if (is_REX_prefix(insn)) ++insn; if (*insn == 0x0f) { @@ -748,11 +761,9 @@ static void __kprobes resume_execution(struct kprobe *p, unsigned long orig_ip = (unsigned long)p->addr; kprobe_opcode_t *insn = p->ainsn.insn; -#ifdef CONFIG_X86_64 /*skip the REX prefix*/ - if (*insn >= 0x40 && *insn <= 0x4f) + if (is_REX_prefix(insn)) insn++; -#endif regs->flags &= ~X86_EFLAGS_TF; switch (*insn) { |