[PATCH] [arch/i386/boot]: for better readability in clearing BSS

[PATCH] [arch/i386/boot]: for better readability in clearing BSS

[Denis Cheng]

there are three different linker scripts with different usages,

	arch/i386/boot/setup.ld
	arch/i386/boot/compressed/vmlinux.lds
	arch/i386/kernel/vmlinux.lds

accompanlying with three different sections of clearing BSS,

	arch/i386/boot/header.S
	arch/i386/boot/compressed/head.S
	arch/i386/kernel/head.S

but their label names in .bss section are different,
when reading these files, they are apt to confuse,

this patch kept them in the same style of clearing.

Signed-off-by: Denis Cheng <crquan@gmail.com>
---
 arch/i386/boot/compressed/head.S |    2 +-
 arch/i386/boot/header.S          |    2 +-
 arch/i386/boot/setup.ld          |    4 ++--
 3 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/arch/i386/boot/compressed/head.S b/arch/i386/boot/compressed/head.S
index f35ea22..e499db0 100644
--- a/arch/i386/boot/compressed/head.S
+++ b/arch/i386/boot/compressed/head.S
@@ -113,7 +113,7 @@ relocated:
  * Clear BSS
  */
 	xorl %eax,%eax
-	leal _edata(%ebx),%edi
+	leal _bss(%ebx),%edi
 	leal _end(%ebx), %ecx
 	subl %edi,%ecx
 	cld
diff --git a/arch/i386/boot/header.S b/arch/i386/boot/header.S
index 7f4a2c5..cd074c1 100644
--- a/arch/i386/boot/header.S
+++ b/arch/i386/boot/header.S
@@ -254,7 +254,7 @@ setup2:
 
 # Zero the bss
 	movw	$__bss_start, %di
-	movw	$_end+3, %cx
+	movw	$__bss_end, %cx
 	xorl	%eax, %eax
 	subw	%di, %cx
 	shrw	$2, %cx
diff --git a/arch/i386/boot/setup.ld b/arch/i386/boot/setup.ld
index df9234b..f9d6897 100644
--- a/arch/i386/boot/setup.ld
+++ b/arch/i386/boot/setup.ld
@@ -36,15 +36,15 @@ SECTIONS
 		LONG(0x5a5aaa55)
 	}
 
-
 	. = ALIGN(16);
 	.bss		:
 	{
 		__bss_start = .;
 		*(.bss)
+		. = ALIGN(16);
 		__bss_end = .;
 	}
-	. = ALIGN(16);
+
 	_end = .;
 
 	/DISCARD/ : { *(.note*) }
-- 
1.5.3.rc4

Re: [PATCH] [arch/i386/boot]: for better readability in clearing BSS

[H. Peter Anvin]

Denis Cheng wrote:
> 
> but their label names in .bss section are different,
> when reading these files, they are apt to confuse,
> 
> this patch kept them in the same style of clearing.
> 

Bullsh*t.

> diff --git a/arch/i386/boot/compressed/head.S b/arch/i386/boot/compressed/head.S
> index f35ea22..e499db0 100644
> --- a/arch/i386/boot/compressed/head.S
> +++ b/arch/i386/boot/compressed/head.S
> @@ -113,7 +113,7 @@ relocated:
>   * Clear BSS
>   */
>  	xorl %eax,%eax
> -	leal _edata(%ebx),%edi
> +	leal _bss(%ebx),%edi
>  	leal _end(%ebx), %ecx
>  	subl %edi,%ecx
>  	cld

Here you change _edata.._end into _bss.._end.

> diff --git a/arch/i386/boot/header.S b/arch/i386/boot/header.S
> index 7f4a2c5..cd074c1 100644
> --- a/arch/i386/boot/header.S
> +++ b/arch/i386/boot/header.S
> @@ -254,7 +254,7 @@ setup2:
>  
>  # Zero the bss
>  	movw	$__bss_start, %di
> -	movw	$_end+3, %cx
> +	movw	$__bss_end, %cx
>  	xorl	%eax, %eax
>  	subw	%di, %cx
>  	shrw	$2, %cx

Here you change __bss_start..to __bss_end, and have to change the linker
script for it not to break.

There is no consistency improvement, and as such, it's just churn.

	-hpa

Re: [PATCH] [arch/i386/boot]: for better readability in clearing BSS

[H. Peter Anvin]

Denis Cheng wrote:
> 
> but their label names in .bss section are different,
> when reading these files, they are apt to confuse,
> 
> this patch kept them in the same style of clearing.
> 

Bullsh*t.

> diff --git a/arch/i386/boot/compressed/head.S b/arch/i386/boot/compressed/head.S
> index f35ea22..e499db0 100644
> --- a/arch/i386/boot/compressed/head.S
> +++ b/arch/i386/boot/compressed/head.S
> @@ -113,7 +113,7 @@ relocated:
>   * Clear BSS
>   */
>  	xorl %eax,%eax
> -	leal _edata(%ebx),%edi
> +	leal _bss(%ebx),%edi
>  	leal _end(%ebx), %ecx
>  	subl %edi,%ecx
>  	cld

Here you change _edata.._end into _bss.._end.

> diff --git a/arch/i386/boot/header.S b/arch/i386/boot/header.S
> index 7f4a2c5..cd074c1 100644
> --- a/arch/i386/boot/header.S
> +++ b/arch/i386/boot/header.S
> @@ -254,7 +254,7 @@ setup2:
>  
>  # Zero the bss
>  	movw	$__bss_start, %di
> -	movw	$_end+3, %cx
> +	movw	$__bss_end, %cx
>  	xorl	%eax, %eax
>  	subw	%di, %cx
>  	shrw	$2, %cx

Here you change __bss_start.._end to __bss_start..__bss_end, and have to
change the linker script for it not to break.

There is no consistency improvement, and as such, it's just churn.

	-hpa