There exists a common function sign_extend64() to sign extend a 64-bit
value using specified bit as sign-bit in include/linux/bitops.h, it is
more efficient, let us use it and remove the arch-specific sign_extend()
under arch/loongarch.

Suggested-by: Jinyang He <hejinyang@loongson.cn>
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
---
 arch/loongarch/include/asm/inst.h   | 8 --------
 arch/loongarch/kernel/alternative.c | 6 +++---
 2 files changed, 3 insertions(+), 11 deletions(-)

diff --git a/arch/loongarch/include/asm/inst.h b/arch/loongarch/include/asm/inst.h
index e0771d2..ba18ce8 100644
--- a/arch/loongarch/include/asm/inst.h
+++ b/arch/loongarch/include/asm/inst.h
@@ -397,14 +397,6 @@ static inline bool unsigned_imm_check(unsigned long val, unsigned int bit)
 	return val < (1UL << bit);
 }
 
-static inline unsigned long sign_extend(unsigned long val, unsigned int idx)
-{
-	if (!is_imm_negative(val, idx + 1))
-		return ((1UL << idx) - 1) & val;
-	else
-		return ~((1UL << idx) - 1) | val;
-}
-
 #define DEF_EMIT_REG0I26_FORMAT(NAME, OP)				\
 static inline void emit_##NAME(union loongarch_instruction *insn,	\
 			       int offset)				\
diff --git a/arch/loongarch/kernel/alternative.c b/arch/loongarch/kernel/alternative.c
index c5aebea..4ad1384 100644
--- a/arch/loongarch/kernel/alternative.c
+++ b/arch/loongarch/kernel/alternative.c
@@ -74,7 +74,7 @@ static void __init_or_module recompute_jump(union loongarch_instruction *buf,
 	switch (src->reg0i26_format.opcode) {
 	case b_op:
 	case bl_op:
-		jump_addr = cur_pc + sign_extend((si_h << 16 | si_l) << 2, 27);
+		jump_addr = cur_pc + sign_extend64((si_h << 16 | si_l) << 2, 27);
 		if (in_alt_jump(jump_addr, start, end))
 			return;
 		offset = jump_addr - pc;
@@ -93,7 +93,7 @@ static void __init_or_module recompute_jump(union loongarch_instruction *buf,
 		fallthrough;
 	case beqz_op:
 	case bnez_op:
-		jump_addr = cur_pc + sign_extend((si_h << 16 | si_l) << 2, 22);
+		jump_addr = cur_pc + sign_extend64((si_h << 16 | si_l) << 2, 22);
 		if (in_alt_jump(jump_addr, start, end))
 			return;
 		offset = jump_addr - pc;
@@ -112,7 +112,7 @@ static void __init_or_module recompute_jump(union loongarch_instruction *buf,
 	case bge_op:
 	case bltu_op:
 	case bgeu_op:
-		jump_addr = cur_pc + sign_extend(si << 2, 17);
+		jump_addr = cur_pc + sign_extend64(si << 2, 17);
 		if (in_alt_jump(jump_addr, start, end))
 			return;
 		offset = jump_addr - pc;
-- 
2.1.0

I queued this patch, but others need more reviews.

Huacai

On Sat, Jan 14, 2023 at 5:27 PM Tiezhu Yang <yangtiezhu@loongson.cn> wrote:
>
> There exists a common function sign_extend64() to sign extend a 64-bit
> value using specified bit as sign-bit in include/linux/bitops.h, it is
> more efficient, let us use it and remove the arch-specific sign_extend()
> under arch/loongarch.
>
> Suggested-by: Jinyang He <hejinyang@loongson.cn>
> Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
> ---
>  arch/loongarch/include/asm/inst.h   | 8 --------
>  arch/loongarch/kernel/alternative.c | 6 +++---
>  2 files changed, 3 insertions(+), 11 deletions(-)
>
> diff --git a/arch/loongarch/include/asm/inst.h b/arch/loongarch/include/asm/inst.h
> index e0771d2..ba18ce8 100644
> --- a/arch/loongarch/include/asm/inst.h
> +++ b/arch/loongarch/include/asm/inst.h
> @@ -397,14 +397,6 @@ static inline bool unsigned_imm_check(unsigned long val, unsigned int bit)
>         return val < (1UL << bit);
>  }
>
> -static inline unsigned long sign_extend(unsigned long val, unsigned int idx)
> -{
> -       if (!is_imm_negative(val, idx + 1))
> -               return ((1UL << idx) - 1) & val;
> -       else
> -               return ~((1UL << idx) - 1) | val;
> -}
> -
>  #define DEF_EMIT_REG0I26_FORMAT(NAME, OP)                              \
>  static inline void emit_##NAME(union loongarch_instruction *insn,      \
>                                int offset)                              \
> diff --git a/arch/loongarch/kernel/alternative.c b/arch/loongarch/kernel/alternative.c
> index c5aebea..4ad1384 100644
> --- a/arch/loongarch/kernel/alternative.c
> +++ b/arch/loongarch/kernel/alternative.c
> @@ -74,7 +74,7 @@ static void __init_or_module recompute_jump(union loongarch_instruction *buf,
>         switch (src->reg0i26_format.opcode) {
>         case b_op:
>         case bl_op:
> -               jump_addr = cur_pc + sign_extend((si_h << 16 | si_l) << 2, 27);
> +               jump_addr = cur_pc + sign_extend64((si_h << 16 | si_l) << 2, 27);
>                 if (in_alt_jump(jump_addr, start, end))
>                         return;
>                 offset = jump_addr - pc;
> @@ -93,7 +93,7 @@ static void __init_or_module recompute_jump(union loongarch_instruction *buf,
>                 fallthrough;
>         case beqz_op:
>         case bnez_op:
> -               jump_addr = cur_pc + sign_extend((si_h << 16 | si_l) << 2, 22);
> +               jump_addr = cur_pc + sign_extend64((si_h << 16 | si_l) << 2, 22);
>                 if (in_alt_jump(jump_addr, start, end))
>                         return;
>                 offset = jump_addr - pc;
> @@ -112,7 +112,7 @@ static void __init_or_module recompute_jump(union loongarch_instruction *buf,
>         case bge_op:
>         case bltu_op:
>         case bgeu_op:
> -               jump_addr = cur_pc + sign_extend(si << 2, 17);
> +               jump_addr = cur_pc + sign_extend64(si << 2, 17);
>                 if (in_alt_jump(jump_addr, start, end))
>                         return;
>                 offset = jump_addr - pc;
> --
> 2.1.0
>