[PATCH] riscv: remove redundant mv instructions

[PATCH] riscv: remove redundant mv instructions

[Nam Cao]

Some mv instructions were useful when first introduced to preserve a0 and
a1 before function calls. However the code has changed and they are now
redundant. Remove them.

Signed-off-by: Nam Cao <namcaov@gmail.com>
---
 arch/riscv/kernel/head.S | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/arch/riscv/kernel/head.S b/arch/riscv/kernel/head.S
index 11c3b94c4534..3710ea5d160f 100644
--- a/arch/riscv/kernel/head.S
+++ b/arch/riscv/kernel/head.S
@@ -289,10 +289,6 @@ clear_bss:
 	blt a3, a4, clear_bss
 clear_bss_done:
 #endif
-	/* Save hart ID and DTB physical address */
-	mv s0, a0
-	mv s1, a1
-
 	la a2, boot_cpu_hartid
 	XIP_FIXUP_OFFSET a2
 	REG_S a0, (a2)
@@ -306,7 +302,7 @@ clear_bss_done:
 	la a0, __dtb_start
 	XIP_FIXUP_OFFSET a0
 #else
-	mv a0, s1
+	mv a0, a1
 #endif /* CONFIG_BUILTIN_DTB */
 	call setup_vm
 #ifdef CONFIG_MMU
-- 
2.34.1

Re: [PATCH] riscv: remove redundant mv instructions

[Alexandre Ghiti]

Hi Nam,


On 25/07/2023 07:38, Nam Cao wrote:
> Some mv instructions were useful when first introduced to preserve a0 and
> a1 before function calls. However the code has changed and they are now
> redundant. Remove them.
>
> Signed-off-by: Nam Cao <namcaov@gmail.com>
> ---
>   arch/riscv/kernel/head.S | 6 +-----
>   1 file changed, 1 insertion(+), 5 deletions(-)
>
> diff --git a/arch/riscv/kernel/head.S b/arch/riscv/kernel/head.S
> index 11c3b94c4534..3710ea5d160f 100644
> --- a/arch/riscv/kernel/head.S
> +++ b/arch/riscv/kernel/head.S
> @@ -289,10 +289,6 @@ clear_bss:
>   	blt a3, a4, clear_bss
>   clear_bss_done:
>   #endif
> -	/* Save hart ID and DTB physical address */
> -	mv s0, a0
> -	mv s1, a1
> -
>   	la a2, boot_cpu_hartid
>   	XIP_FIXUP_OFFSET a2
>   	REG_S a0, (a2)
> @@ -306,7 +302,7 @@ clear_bss_done:
>   	la a0, __dtb_start
>   	XIP_FIXUP_OFFSET a0
>   #else
> -	mv a0, s1
> +	mv a0, a1
>   #endif /* CONFIG_BUILTIN_DTB */
>   	call setup_vm
>   #ifdef CONFIG_MMU


You can add:

Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com>

Thanks,

Alex

Re: [PATCH] riscv: remove redundant mv instructions

[patchwork-bot+linux-riscv]

Hello:

This patch was applied to riscv/linux.git (for-next)
by Palmer Dabbelt <palmer@rivosinc.com>:

On Tue, 25 Jul 2023 07:38:35 +0200 you wrote:
> Some mv instructions were useful when first introduced to preserve a0 and
> a1 before function calls. However the code has changed and they are now
> redundant. Remove them.
> 
> Signed-off-by: Nam Cao <namcaov@gmail.com>
> ---
>  arch/riscv/kernel/head.S | 6 +-----
>  1 file changed, 1 insertion(+), 5 deletions(-)

Here is the summary with links:
  - riscv: remove redundant mv instructions
    https://git.kernel.org/riscv/c/10f763532d58

You are awesome, thank you!
-- 
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html

Re: [PATCH] riscv: remove redundant mv instructions

[Palmer Dabbelt]

On Tue, 25 Jul 2023 07:38:35 +0200, Nam Cao wrote:
> Some mv instructions were useful when first introduced to preserve a0 and
> a1 before function calls. However the code has changed and they are now
> redundant. Remove them.
> 
> 

Applied, thanks!

[1/1] riscv: remove redundant mv instructions
      https://git.kernel.org/palmer/c/10f763532d58

Best regards,
-- 
Palmer Dabbelt <palmer@rivosinc.com>