On 2018/10/30 16:36, Peter Zijlstra wrote:
On Mon, Oct 29, 2018 at 11:55:06PM -0700, Zhenzhong Duan wrote:
Since CONFIG_RETPOLINE hard depends on compiler support now, so
replacing indirect-jump check with the range check is safe in that case.
Can we put kprobes on module init text before we run alternatives on it?
Forgive me I doesn't understand your question. Do you mean this patch
impact kprobes on module init text?
@@ -240,20 +242,16 @@ static int insn_jump_into_range(struct insn *insn,
unsigned long start, int len)
static int insn_is_indirect_jump(struct insn *insn)
{
- int ret = __insn_is_indirect_jump(insn);
+ int ret;
#ifdef CONFIG_RETPOLINE
- /*
- * Jump to x86_indirect_thunk_* is treated as an indirect jump.
- * Note that even with CONFIG_RETPOLINE=y, the kernel compiled with
- * older gcc may use indirect jump. So we add this check instead of
- * replace indirect-jump check.
- */
- if (!ret)
+ /* Jump to x86_indirect_thunk_* is treated as an indirect jump. */
ret = insn_jump_into_range(insn,
(unsigned long)__indirect_thunk_start,
(unsigned long)__indirect_thunk_end -
(unsigned long)__indirect_thunk_start);
+#else
+ ret = __insn_is_indirect_jump(insn);
#endif
return ret;
}
The resulting code is indented wrong.
Oh, yes. Thanks for point out.
Zhenzhong
