To avoid duplication of inline asm between C and Rust, we need to
import the inline asm from the relevant `jump_label.h` header into Rust.
To make that easier, this patch updates the header files to expose the
inline asm via a new ARCH_STATIC_BRANCH_ASM macro.

The header files are all updated to define a ARCH_STATIC_BRANCH_ASM that
takes the same arguments in a consistent order so that Rust can use the
same logic for every architecture.

Suggested-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Co-developed-by: Miguel Ojeda <ojeda@kernel.org>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Alice Ryhl <aliceryhl@google.com>
---
 arch/arm/include/asm/jump_label.h       | 14 +++++----
 arch/arm64/include/asm/jump_label.h     | 20 ++++++++-----
 arch/loongarch/include/asm/jump_label.h | 16 +++++++----
 arch/riscv/include/asm/jump_label.h     | 50 ++++++++++++++++++---------------
 arch/x86/include/asm/jump_label.h       | 39 +++++++++++--------------
 5 files changed, 76 insertions(+), 63 deletions(-)

diff --git a/arch/arm/include/asm/jump_label.h b/arch/arm/include/asm/jump_label.h
index e4eb54f6cd9f..a35aba7f548c 100644
--- a/arch/arm/include/asm/jump_label.h
+++ b/arch/arm/include/asm/jump_label.h
@@ -9,13 +9,17 @@
 
 #define JUMP_LABEL_NOP_SIZE 4
 
+/* This macro is also expanded on the Rust side. */
+#define ARCH_STATIC_BRANCH_ASM(key, label)		\
+	"1:\n\t"					\
+	WASM(nop) "\n\t"				\
+	".pushsection __jump_table,  \"aw\"\n\t"	\
+	".word 1b, " label ", " key "\n\t"		\
+	".popsection\n\t"				\
+
 static __always_inline bool arch_static_branch(struct static_key *key, bool branch)
 {
-	asm goto("1:\n\t"
-		 WASM(nop) "\n\t"
-		 ".pushsection __jump_table,  \"aw\"\n\t"
-		 ".word 1b, %l[l_yes], %c0\n\t"
-		 ".popsection\n\t"
+	asm goto(ARCH_STATIC_BRANCH_ASM("%c0", "%l[l_yes]")
 		 : :  "i" (&((char *)key)[branch]) :  : l_yes);
 
 	return false;
diff --git a/arch/arm64/include/asm/jump_label.h b/arch/arm64/include/asm/jump_label.h
index a0a5bbae7229..424ed421cd97 100644
--- a/arch/arm64/include/asm/jump_label.h
+++ b/arch/arm64/include/asm/jump_label.h
@@ -19,10 +19,14 @@
 #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
+	".long		1b - ., " label " - .\n\t"	\
+	".quad		" key " - .\n\t"		\
+	".popsection\n\t"
+
+/* This macro is also expanded on the Rust side. */
+#define ARCH_STATIC_BRANCH_ASM(key, label)		\
+	"1:	nop\n\t"				\
+	JUMP_TABLE_ENTRY(key, label)
 
 static __always_inline bool arch_static_branch(struct static_key * const key,
 					       const bool branch)
@@ -30,8 +34,8 @@ static __always_inline bool arch_static_branch(struct static_key * const key,
 	char *k = &((char *)key)[branch];
 
 	asm goto(
-		"1:	nop					\n\t"
-		JUMP_TABLE_ENTRY(k, l_yes)
+		ARCH_STATIC_BRANCH_ASM("%c0", "%l[l_yes]")
+		:  :  "i"(k) :  : l_yes
 		);
 
 	return false;
@@ -43,9 +47,11 @@ static __always_inline bool arch_static_branch_jump(struct static_key * const ke
 						    const bool branch)
 {
 	char *k = &((char *)key)[branch];
+
 	asm goto(
 		"1:	b		%l[l_yes]		\n\t"
-		JUMP_TABLE_ENTRY(k, l_yes)
+		JUMP_TABLE_ENTRY("%c0", "%l[l_yes]")
+		:  :  "i"(k) :  : l_yes
 		);
 	return false;
 l_yes:
diff --git a/arch/loongarch/include/asm/jump_label.h b/arch/loongarch/include/asm/jump_label.h
index 29acfe3de3fa..8a924bd69d19 100644
--- a/arch/loongarch/include/asm/jump_label.h
+++ b/arch/loongarch/include/asm/jump_label.h
@@ -13,18 +13,22 @@
 
 #define JUMP_LABEL_NOP_SIZE	4
 
-#define JUMP_TABLE_ENTRY				\
+/* This macro is also expanded on the Rust side. */
+#define JUMP_TABLE_ENTRY(key, label)			\
 	 ".pushsection	__jump_table, \"aw\"	\n\t"	\
 	 ".align	3			\n\t"	\
-	 ".long		1b - ., %l[l_yes] - .	\n\t"	\
-	 ".quad		%0 - .			\n\t"	\
+	 ".long		1b - ., " label " - .	\n\t"	\
+	 ".quad		" key " - .		\n\t"	\
 	 ".popsection				\n\t"
 
+#define ARCH_STATIC_BRANCH_ASM(key, label)		\
+	"1:	nop				\n\t"	\
+	JUMP_TABLE_ENTRY(key, label)
+
 static __always_inline bool arch_static_branch(struct static_key * const key, const bool branch)
 {
 	asm goto(
-		"1:	nop			\n\t"
-		JUMP_TABLE_ENTRY
+		ARCH_STATIC_BRANCH_ASM("%0", "%l[l_yes]")
 		:  :  "i"(&((char *)key)[branch]) :  : l_yes);
 
 	return false;
@@ -37,7 +41,7 @@ static __always_inline bool arch_static_branch_jump(struct static_key * const ke
 {
 	asm goto(
 		"1:	b	%l[l_yes]	\n\t"
-		JUMP_TABLE_ENTRY
+		JUMP_TABLE_ENTRY("%0", "%l[l_yes]")
 		:  :  "i"(&((char *)key)[branch]) :  : l_yes);
 
 	return false;
diff --git a/arch/riscv/include/asm/jump_label.h b/arch/riscv/include/asm/jump_label.h
index 1c768d02bd0c..87a71cc6d146 100644
--- a/arch/riscv/include/asm/jump_label.h
+++ b/arch/riscv/include/asm/jump_label.h
@@ -16,21 +16,28 @@
 
 #define JUMP_LABEL_NOP_SIZE 4
 
+#define JUMP_TABLE_ENTRY(key, label)			\
+	".pushsection	__jump_table, \"aw\"	\n\t"	\
+	".align		" RISCV_LGPTR "		\n\t"	\
+	".long		1b - ., " label " - .	\n\t"	\
+	"" RISCV_PTR "	" key " - .		\n\t"	\
+	".popsection				\n\t"
+
+/* This macro is also expanded on the Rust side. */
+#define ARCH_STATIC_BRANCH_ASM(key, label)		\
+	"	.align		2		\n\t"	\
+	"	.option push			\n\t"	\
+	"	.option norelax			\n\t"	\
+	"	.option norvc			\n\t"	\
+	"1:	nop				\n\t"	\
+	"	.option pop			\n\t"	\
+	JUMP_TABLE_ENTRY(key, label)
+
 static __always_inline bool arch_static_branch(struct static_key * const key,
 					       const bool branch)
 {
 	asm goto(
-		"	.align		2			\n\t"
-		"	.option push				\n\t"
-		"	.option norelax				\n\t"
-		"	.option norvc				\n\t"
-		"1:	nop					\n\t"
-		"	.option pop				\n\t"
-		"	.pushsection	__jump_table, \"aw\"	\n\t"
-		"	.align		" RISCV_LGPTR "		\n\t"
-		"	.long		1b - ., %l[label] - .	\n\t"
-		"	" RISCV_PTR "	%0 - .			\n\t"
-		"	.popsection				\n\t"
+		ARCH_STATIC_BRANCH_ASM("%0", "%l[label]")
 		:  :  "i"(&((char *)key)[branch]) :  : label);
 
 	return false;
@@ -38,21 +45,20 @@ static __always_inline bool arch_static_branch(struct static_key * const key,
 	return true;
 }
 
+#define ARCH_STATIC_BRANCH_JUMP_ASM(key, label)		\
+	"	.align		2		\n\t"	\
+	"	.option push			\n\t"	\
+	"	.option norelax			\n\t"	\
+	"	.option norvc			\n\t"	\
+	"1:	j	" label "		\n\t" \
+	"	.option pop			\n\t"	\
+	JUMP_TABLE_ENTRY(key, label)
+
 static __always_inline bool arch_static_branch_jump(struct static_key * const key,
 						    const bool branch)
 {
 	asm goto(
-		"	.align		2			\n\t"
-		"	.option push				\n\t"
-		"	.option norelax				\n\t"
-		"	.option norvc				\n\t"
-		"1:	j		%l[label]		\n\t"
-		"	.option pop				\n\t"
-		"	.pushsection	__jump_table, \"aw\"	\n\t"
-		"	.align		" RISCV_LGPTR "		\n\t"
-		"	.long		1b - ., %l[label] - .	\n\t"
-		"	" RISCV_PTR "	%0 - .			\n\t"
-		"	.popsection				\n\t"
+		ARCH_STATIC_BRANCH_JUMP_ASM("%0", "%l[label]")
 		:  :  "i"(&((char *)key)[branch]) :  : label);
 
 	return false;
diff --git a/arch/x86/include/asm/jump_label.h b/arch/x86/include/asm/jump_label.h
index cbbef32517f0..ffd0d1a1a4af 100644
--- a/arch/x86/include/asm/jump_label.h
+++ b/arch/x86/include/asm/jump_label.h
@@ -12,49 +12,42 @@
 #include <linux/stringify.h>
 #include <linux/types.h>
 
-#define JUMP_TABLE_ENTRY				\
+#define JUMP_TABLE_ENTRY(key, label)			\
 	".pushsection __jump_table,  \"aw\" \n\t"	\
 	_ASM_ALIGN "\n\t"				\
 	".long 1b - . \n\t"				\
-	".long %l[l_yes] - . \n\t"			\
-	_ASM_PTR "%c0 + %c1 - .\n\t"			\
+	".long " label " - . \n\t"			\
+	_ASM_PTR " " key " - . \n\t"			\
 	".popsection \n\t"
 
+/* This macro is also expanded on the Rust side. */
 #ifdef CONFIG_HAVE_JUMP_LABEL_HACK
-
-static __always_inline bool arch_static_branch(struct static_key *key, bool branch)
-{
-	asm goto("1:"
-		"jmp %l[l_yes] # objtool NOPs this \n\t"
-		JUMP_TABLE_ENTRY
-		: :  "i" (key), "i" (2 | branch) : : l_yes);
-
-	return false;
-l_yes:
-	return true;
-}
-
+#define ARCH_STATIC_BRANCH_ASM(key, label)		\
+	"1: jmp " label " # objtool NOPs this \n\t"	\
+	JUMP_TABLE_ENTRY(key, label)
 #else /* !CONFIG_HAVE_JUMP_LABEL_HACK */
+#define ARCH_STATIC_BRANCH_ASM(key, label)		\
+	"1: .byte " __stringify(BYTES_NOP5) "\n\t"	\
+	JUMP_TABLE_ENTRY(key, label)
+#endif /* CONFIG_HAVE_JUMP_LABEL_HACK */
 
 static __always_inline bool arch_static_branch(struct static_key * const key, const bool branch)
 {
-	asm goto("1:"
-		".byte " __stringify(BYTES_NOP5) "\n\t"
-		JUMP_TABLE_ENTRY
-		: :  "i" (key), "i" (branch) : : l_yes);
+	int hack_bit = IS_ENABLED(CONFIG_HAVE_JUMP_LABEL_HACK) ? 2 : 0;
+
+	asm goto(ARCH_STATIC_BRANCH_ASM("%c0 + %c1", "%l[l_yes]")
+		: :  "i" (key), "i" (hack_bit | branch) : : l_yes);
 
 	return false;
 l_yes:
 	return true;
 }
 
-#endif /* CONFIG_HAVE_JUMP_LABEL_HACK */
-
 static __always_inline bool arch_static_branch_jump(struct static_key * const key, const bool branch)
 {
 	asm goto("1:"
 		"jmp %l[l_yes]\n\t"
-		JUMP_TABLE_ENTRY
+		JUMP_TABLE_ENTRY("%c0 + %c1", "%l[l_yes]")
 		: :  "i" (key), "i" (branch) : : l_yes);
 
 	return false;

-- 
2.47.0.rc1.288.g06298d1525-goog