kasan: default to inline instrumentation

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>

diff --git a/lib/Kconfig.kasan b/lib/Kconfig.kasan
index fdca89c057452e7715a21316a1d3b763a525d785..935eda08b1e1efd89ef2b65b2ba0ab2f8ab4a889 100644 (file)
--- 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"