From f64366efd8c60b93138b813d071d2cd201fd0f6e Mon Sep 17 00:00:00 2001
From: Peter Zijlstra <peterz@infradead.org>
Date: Thu, 20 Feb 2020 13:28:06 +0100
Subject: [PATCH] x86/int3: Inline bsearch()
Avoid calling out to bsearch() by inlining it, for normal kernel configs
this was the last external call and poke_int3_handler() is now fully self
sufficient -- no calls to external code.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Acked-by: Andy Lutomirski <luto@kernel.org>
Link: https://lkml.kernel.org/r/20200505135313.731774429@linutronix.de
---
arch/x86/kernel/alternative.c | 8 ++++----
arch/x86/kernel/traps.c | 5 +++++
2 files changed, 9 insertions(+), 4 deletions(-)
diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
index 50a8d24a417ed..8fd39ff74a499 100644
--- a/arch/x86/kernel/alternative.c
+++ b/arch/x86/kernel/alternative.c
@@ -1033,7 +1033,7 @@ static __always_inline void *text_poke_addr(struct text_poke_loc *tp)
return _stext + tp->rel_addr;
}
-static int noinstr patch_cmp(const void *key, const void *elt)
+static __always_inline int patch_cmp(const void *key, const void *elt)
{
struct text_poke_loc *tp = (struct text_poke_loc *) elt;
@@ -1077,9 +1077,9 @@ int noinstr poke_int3_handler(struct pt_regs *regs)
* Skip the binary search if there is a single member in the vector.
*/
if (unlikely(desc->nr_entries > 1)) {
- tp = bsearch(ip, desc->vec, desc->nr_entries,
- sizeof(struct text_poke_loc),
- patch_cmp);
+ tp = __inline_bsearch(ip, desc->vec, desc->nr_entries,
+ sizeof(struct text_poke_loc),
+ patch_cmp);
if (!tp)
goto out_put;
} else {
diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index b28a64d7691fb..280c290f414f0 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -570,6 +570,11 @@ exit:
dotraplinkage void notrace do_int3(struct pt_regs *regs, long error_code)
{
+ /*
+ * poke_int3_handler() is completely self contained code; it does (and
+ * must) *NOT* call out to anything, lest it hits upon yet another
+ * INT3.
+ */
if (poke_int3_handler(regs))
return;
--
2.30.2