linux-kernel - [PATCH v3 1/1] arm64: simplify arch_static_branch/

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Date: Tue, 30 Apr 2024 16:56:55 +0800
From: George Guo <dongtai.guo@...ux.dev>
To: mark.rutland@....com
Cc: ardb@...nel.org,
	catalin.marinas@....com,
	dongtai.guo@...ux.dev,
	guodongtai@...inos.cn,
	jbaron@...mai.com,
	jpoimboe@...nel.org,
	linux-arm-kernel@...ts.infradead.org,
	linux-kernel@...r.kernel.org,
	peterz@...radead.org,
	rostedt@...dmis.org,
	will@...nel.org
Subject: [PATCH v3 1/1] arm64: simplify arch_static_branch/_jump function

From: George Guo <guodongtai@...inos.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@...inos.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