From 83a6fdd6c27d4f6f51fa1092805676b24e0f8827 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Paul=20Heidekr=C3=BCger?= <paul.heidekrueger@tum.de>
Date: Thu, 9 Nov 2023 15:51:00 +0000
Subject: [PATCH] kasan: default to inline instrumentation
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KASan inline instrumentation can yield up to a 2x performance gain at the
cost of a larger binary.

Make inline instrumentation the default, as suggested in the bug report
below.

When an architecture does not support inline instrumentation, it should
set ARCH_DISABLE_KASAN_INLINE, as done by PowerPC, for instance.

Link: https://lkml.kernel.org/r/20231109155101.186028-1-paul.heidekrueger@tum.de
Signed-off-by: Paul Heidekrüger <paul.heidekrueger@tum.de>
Reported-by: Andrey Konovalov <andreyknvl@gmail.com>
Reviewed-by: Marco Elver <elver@google.com>
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=203495
Acked-by: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
 lib/Kconfig.kasan | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/Kconfig.kasan b/lib/Kconfig.kasan
index fdca89c05745..935eda08b1e1 100644
--- a/lib/Kconfig.kasan
+++ b/lib/Kconfig.kasan
@@ -134,7 +134,7 @@ endchoice
 choice
 	prompt "Instrumentation type"
 	depends on KASAN_GENERIC || KASAN_SW_TAGS
-	default KASAN_OUTLINE
+	default KASAN_INLINE if !ARCH_DISABLE_KASAN_INLINE
 
 config KASAN_OUTLINE
 	bool "Outline instrumentation"