[RFC PATCH v4 16/37] arm64: Add annotate_reachable() for objtools

[Chen Zhongjin <chenzhongjin@huawei.com>]

x86 removed annotate_reachable and replaced it with ASM_REACHABLE
which is not suitable for arm64 micro because there are some cases
GCC will merge duplicate inline asm.

Re-add annotation_reachable() for arm64.

Signed-off-by: Chen Zhongjin <chenzhongjin@huawei.com>
---
 include/linux/compiler.h | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/include/linux/compiler.h b/include/linux/compiler.h
index 219aa5ddbc73..6a14e4bae37d 100644
--- a/include/linux/compiler.h
+++ b/include/linux/compiler.h
@@ -117,6 +117,14 @@ void ftrace_likely_update(struct ftrace_likely_data *f, int val,
  */
 #define __stringify_label(n) #n
 
+#define __annotate_reachable(c) ({					\
+	asm volatile(__stringify_label(c) ":\n\t"			\
+			".pushsection .discard.reachable\n\t"		\
+			".long " __stringify_label(c) "b - .\n\t"		\
+			".popsection\n\t");				\
+})
+#define annotate_reachable() __annotate_reachable(__COUNTER__)
+
 #define __annotate_unreachable(c) ({					\
 	asm volatile(__stringify_label(c) ":\n\t"			\
 		     ".pushsection .discard.unreachable\n\t"		\
@@ -129,6 +137,7 @@ void ftrace_likely_update(struct ftrace_likely_data *f, int val,
 #define __annotate_jump_table __section(".rodata..c_jump_table")
 
 #else
+#define annotate_reachable()
 #define annotate_unreachable()
 #define __annotate_jump_table
 #endif
-- 
2.17.1