[PATCH 1/2] compiler: define __ll_elem for linker list elements

[Ahmad Fatoum <a.fatoum@pengutronix.de>]

When built with clang + AddressSanitizer, global variables end up with
a redzone that breaks linker list elements.

The __no_sanitize_address attribute prevents these redzones, but GCC
isn't happy about applying it to anything but functions. Therefore
define a __ll_elem macro for defining linker list elements that takes
care to avoid these redzones when building with clang.

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
---
 include/linux/compiler_types.h | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/include/linux/compiler_types.h b/include/linux/compiler_types.h
index 9ef8115a396f..d925b3da296d 100644
--- a/include/linux/compiler_types.h
+++ b/include/linux/compiler_types.h
@@ -274,6 +274,12 @@ struct ftrace_likely_data {
 #define __cold			__attribute__((cold))
 #define __section(S)		__attribute__((__section__(#S)))
 
+#ifdef __clang__
+#define __ll_elem(S)		__section(S) __used __no_sanitize_address
+#else
+#define __ll_elem(S)		__section(S) __used
+#endif
+
 
 #ifdef CONFIG_ENABLE_MUST_CHECK
 #define __must_check		__attribute__((warn_unused_result))
-- 
2.39.2