[PATCH v1 1/2] riscv: introduce assembly version of jump table

[Andy Chiu]

This is the introductary patch for us to call the user copy that
supports fast unaligned access after the runtime detection.

Signed-off-by: Andy Chiu <tchiu at tenstorrent.com>
---
 arch/riscv/include/asm/jump_label.h | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)

diff --git a/arch/riscv/include/asm/jump_label.h b/arch/riscv/include/asm/jump_label.h
index 3ab5f2e3212b..d75961ed3324 100644
--- a/arch/riscv/include/asm/jump_label.h
+++ b/arch/riscv/include/asm/jump_label.h
@@ -65,6 +65,32 @@ static __always_inline bool arch_static_branch_jump(struct static_key * const ke
 label:
 	return true;
 }
+#else
+#include <asm/asm.h>
+
+#define JUMP_TABLE_ENTRY(key, label)			\
+	.pushsection	__jump_table, "aw";		\
+	.align		RISCV_LGPTR;			\
+	.long		1b - ., label - .;		\
+	RISCV_PTR	key - .;			\
+	.popsection
+
+#define ARCH_STATIC_BRANCH_ASM(key, label)		\
+	.align		2;				\
+	.option push;					\
+	.option norelax;				\
+	.option norvc;					\
+1:	nop;						\
+	.option pop;					\
+	JUMP_TABLE_ENTRY(key, label)
 
+#define ARCH_STATIC_BRANCH_JUMP_ASM(key, label)		\
+	.align		2;				\
+	.option push;					\
+	.option norelax;				\
+	.option norvc;					\
+1:	j		label;				\
+	.option pop;					\
+	JUMP_TABLE_ENTRY(key, label)
 #endif  /* __ASSEMBLER__ */
 #endif	/* __ASM_JUMP_LABEL_H */
-- 
2.43.0