[tip: locking/kcsan] compiler_types.h, kasan: Use __SANITIZE_ADDRESS__ instead of CONFIG_KASAN to decide inlining

[tip-bot2 for Marco Elver]

The following commit has been merged into the locking/kcsan branch of tip:

Commit-ID:     b91caf58f6fb88738f444cf40d247475c367de47
Gitweb:        https://git.kernel.org/tip/b91caf58f6fb88738f444cf40d247475c367de47
Author:        Marco Elver <elver@xxxxxxxxxx>
AuthorDate:    Thu, 21 May 2020 16:20:47 +02:00
Committer:     Borislav Petkov <bp@xxxxxxx>
CommitterDate: Fri, 22 May 2020 15:31:04 +02:00

compiler_types.h, kasan: Use __SANITIZE_ADDRESS__ instead of CONFIG_KASAN to decide inlining

Use __always_inline in compilation units that have instrumentation
disabled (KASAN_SANITIZE_foo.o := n) for KASAN, like it is done for
KCSAN.

Also, add common documentation for KASAN and KCSAN explaining the
attribute.

 [ bp: Massage commit message. ]

Signed-off-by: Marco Elver <elver@xxxxxxxxxx>
Signed-off-by: Borislav Petkov <bp@xxxxxxx>
Acked-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Acked-by: Will Deacon <will@xxxxxxxxxx>
Link: https://lkml.kernel.org/r/20200521142047.169334-12-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 b190a12..5faf68e 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