[PATCH -tip v3 11/11] compiler_types.h, kasan: Use __SANITIZE_ADDRESS__ instead of CONFIG_KASAN to decide inlining

[Marco Elver]

Like is done for KCSAN, for KASAN we should also use __always_inline in
compilation units that have instrumentation disabled
(KASAN_SANITIZE_foo.o := n). Adds common documentation for KASAN and
KCSAN explaining the attribute.

Acked-by: Will Deacon <will@xxxxxxxxxx>
Signed-off-by: Marco Elver <elver@xxxxxxxxxx>
---
 include/linux/compiler_types.h | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/include/linux/compiler_types.h b/include/linux/compiler_types.h
index b190a12e7089..5faf68eae204 100644
--- a/include/linux/compiler_types.h
+++ b/include/linux/compiler_types.h
@@ -167,7 +167,14 @@ struct ftrace_likely_data {
  */
 #define noinline_for_stack noinline
 
-#ifdef CONFIG_KASAN
+/*
+ * Sanitizer helper attributes: Because using __always_inline and
+ * __no_sanitize_* conflict, provide helper attributes that will either expand
+ * to __no_sanitize_* in compilation units where instrumentation is enabled
+ * (__SANITIZE_*__), or __always_inline in compilation units without
+ * instrumentation (__SANITIZE_*__ undefined).
+ */
+#ifdef __SANITIZE_ADDRESS__
 /*
  * We can't declare function 'inline' because __no_sanitize_address conflicts
  * with inlining. Attempt to inline it may cause a build failure.
@@ -182,10 +189,6 @@ struct ftrace_likely_data {
 
 #define __no_kcsan __no_sanitize_thread
 #ifdef __SANITIZE_THREAD__
-/*
- * Rely on __SANITIZE_THREAD__ instead of CONFIG_KCSAN, to avoid not inlining in
- * compilation units where instrumentation is disabled.
- */
 # define __no_kcsan_or_inline __no_kcsan notrace __maybe_unused
 # define __no_sanitize_or_inline __no_kcsan_or_inline
 #else
-- 
2.26.2.761.g0e0b3e54be-goog