[PATCH v3 1/1] arm64: simplify arch_static_branch/_jump function

George Guo dongtai.guo at linux.dev
Tue Apr 30 01:56:55 PDT 2024


From: George Guo <guodongtai at kylinos.cn>

Extracted the jump table definition code from the arch_static_branch and
arch_static_branch_jump functions into a macro JUMP_TABLE_ENTRY to reduce
code duplication.

Signed-off-by: George Guo <guodongtai at kylinos.cn>
---
 arch/arm64/include/asm/jump_label.h | 28 +++++++++++++++-------------
 1 file changed, 15 insertions(+), 13 deletions(-)

diff --git a/arch/arm64/include/asm/jump_label.h b/arch/arm64/include/asm/jump_label.h
index 6aafbb789991..d43fce47feb9 100644
--- a/arch/arm64/include/asm/jump_label.h
+++ b/arch/arm64/include/asm/jump_label.h
@@ -15,17 +15,23 @@
 
 #define JUMP_LABEL_NOP_SIZE		AARCH64_INSN_SIZE
 
+#define JUMP_TABLE_ENTRY(key, label)			\
+	".pushsection	__jump_table, \"aw\"\n\t"	\
+	".align		3\n\t"				\
+	".long		1b - ., %l["#label"] - .\n\t"	\
+	".quad		%c0 - .\n\t"			\
+	".popsection\n\t"				\
+	:  :  "i"(key) :  : label
+
 static __always_inline bool arch_static_branch(struct static_key * const key,
 					       const bool branch)
 {
+	char *k = &((char *)key)[branch];
+
 	asm goto(
 		"1:	nop					\n\t"
-		 "	.pushsection	__jump_table, \"aw\"	\n\t"
-		 "	.align		3			\n\t"
-		 "	.long		1b - ., %l[l_yes] - .	\n\t"
-		 "	.quad		%c0 - .			\n\t"
-		 "	.popsection				\n\t"
-		 :  :  "i"(&((char *)key)[branch]) :  : l_yes);
+		JUMP_TABLE_ENTRY(k, l_yes)
+		);
 
 	return false;
 l_yes:
@@ -35,15 +41,11 @@ static __always_inline bool arch_static_branch(struct static_key * const key,
 static __always_inline bool arch_static_branch_jump(struct static_key * const key,
 						    const bool branch)
 {
+	char *k = &((char *)key)[branch];
 	asm goto(
 		"1:	b		%l[l_yes]		\n\t"
-		 "	.pushsection	__jump_table, \"aw\"	\n\t"
-		 "	.align		3			\n\t"
-		 "	.long		1b - ., %l[l_yes] - .	\n\t"
-		 "	.quad		%c0 - .			\n\t"
-		 "	.popsection				\n\t"
-		 :  :  "i"(&((char *)key)[branch]) :  : l_yes);
-
+		JUMP_TABLE_ENTRY(k, l_yes)
+		);
 	return false;
 l_yes:
 	return true;
-- 
2.34.1




More information about the linux-arm-kernel mailing list