[PATCH] arm: move _end to linker symbols

Eugen Hristev eugen.hristev at collabora.com
Tue May 28 08:40:42 CEST 2024


On 5/28/24 09:18, Ilias Apalodimas wrote:
> commit 6e2228fb052b ("Merge patch series "Clean up arm linker scripts")
> was cleaning up linker scripts for armv7 and v8 but was leaving
> _end and __secure_stack_start/end.
> 
> commit d0b5d9da5de2 ("arm: make _end compiler-generated")
> was moving _end to be compiler generated. _end is defined as c variable
> in its own section to force the compiler emit relative a reference.
> However, defining those in the linker script will do the same thing
> since [0].
> 
> So let's remove the special sections from the linker scripts, the
> variable definitions from sections.c and define them as a symbols.
> It's worth noting that _image_binary_end symbol is now redundant and
> can be removed in the future.
> 
> - SPL
> 
> The .end section has been removed from the new binary
> [ 5] .end
>      PROGBITS         00000000fffdf488  000000000002f488  0
>      0000000000000000 0000000000000000  0                 1
>      [0000000000000003]: WRITE, ALLOC
> 
> $~ bloat-o-meter kria_old/spl/u-boot-spl krina_new/spl/u-boot-spl
> add/remove: 0/0 grow/shrink: 0/0 up/down: 0/0 (0)
> Function                                     old     new   delta
> Total: Before=115980, After=115980, chg +0.00%
> 
> $~ readelf -sW kria_old/u-boot kria_new/u-boot | grep -w _end
>  12047: 000000000813a0f0     0 OBJECT  GLOBAL DEFAULT   11 _end
>  12047: 000000000813a118     0 NOTYPE  GLOBAL DEFAULT   11 _end
> 
> $~ readelf -sW kria_old/spl/u-boot-spl kria_new/spl/u-boot-spl | grep -w _end
>   1605: 00000000fffdf488     0 OBJECT  GLOBAL DEFAULT    5 _end
>   1603: 00000000fffdf498     0 NOTYPE  GLOBAL DEFAULT    4 _end
> 
> $~ readelf -sW old/u-boot new/u-boot | grep -w _end
>   8847: 0000000000103710     0 OBJECT  GLOBAL DEFAULT   11 _end
>   8847: 0000000000103738     0 NOTYPE  GLOBAL DEFAULT   11 _end
> 
> $~ readelf -sW old_v7/u-boot new_v7/u-boot | grep -w _end
>  10638: 000da824     0 OBJECT  GLOBAL DEFAULT   10 _end
>  10637: 000da84c     0 NOTYPE  GLOBAL DEFAULT   10 _end
> 
> - For both QEMU instances
> $~ bloat-o-meter old/u-boot new/u-boot
> add/remove: 0/0 grow/shrink: 1/0 up/down: 20/0 (20)
> Function                                     old     new   delta
> version_string                                50      70     +20
> Total: Before=656915, After=656935, chg +0.00%
> 
> [0] binutils commit 6b3b0ab89663 ("Make linker assigned symbol dynamic only for shared object")
> 
> Signed-off-by: Ilias Apalodimas <ilias.apalodimas at linaro.org>
> ---
>  arch/arm/cpu/arm1136/u-boot-spl.lds            | 6 +-----
>  arch/arm/cpu/arm926ejs/mxs/u-boot-spl.lds      | 6 +-----
>  arch/arm/cpu/armv8/u-boot-spl.lds              | 7 +------
>  arch/arm/cpu/u-boot-spl.lds                    | 6 +-----
>  arch/arm/cpu/u-boot.lds                        | 6 +-----
>  arch/arm/lib/sections.c                        | 1 -
>  arch/arm/mach-aspeed/ast2600/u-boot-spl.lds    | 6 +-----
>  arch/arm/mach-at91/arm926ejs/u-boot-spl.lds    | 7 +------
>  arch/arm/mach-at91/armv7/u-boot-spl.lds        | 7 +------
>  arch/arm/mach-omap2/u-boot-spl.lds             | 7 +------
>  arch/arm/mach-rockchip/u-boot-tpl-v8.lds       | 7 +------
>  arch/arm/mach-zynq/u-boot.lds                  | 6 +-----
>  board/davinci/da8xxevm/u-boot-spl-da850evm.lds | 7 +------
>  board/samsung/common/exynos-uboot-spl.lds      | 6 +-----
>  14 files changed, 13 insertions(+), 72 deletions(-)
> 
> diff --git a/arch/arm/cpu/arm1136/u-boot-spl.lds b/arch/arm/cpu/arm1136/u-boot-spl.lds
> index f83988fd7e6a..b7af29183a97 100644
> --- a/arch/arm/cpu/arm1136/u-boot-spl.lds
> +++ b/arch/arm/cpu/arm1136/u-boot-spl.lds
> @@ -33,11 +33,7 @@ SECTIONS
>  	.data : { *(SORT_BY_ALIGNMENT(.data*)) } >.sram
>  	. = ALIGN(4);
>  	__image_copy_end = .;
> -
> -	.end :
> -	{
> -		*(.__end)
> -	}
> +	_end = .;
>  
>  	.bss :
>  	{
> diff --git a/arch/arm/cpu/arm926ejs/mxs/u-boot-spl.lds b/arch/arm/cpu/arm926ejs/mxs/u-boot-spl.lds
> index 7e20448f8108..7c6309246f8b 100644
> --- a/arch/arm/cpu/arm926ejs/mxs/u-boot-spl.lds
> +++ b/arch/arm/cpu/arm926ejs/mxs/u-boot-spl.lds
> @@ -49,11 +49,7 @@ SECTIONS
>  		__bss_end = .;
>  	}
>  
> -	.end :
> -	{
> -		*(.__end)
> -	}
> -
> +	_end = .;
>  	_image_binary_end = .;
>  
>  	.dynsym _image_binary_end : { *(.dynsym) }
> diff --git a/arch/arm/cpu/armv8/u-boot-spl.lds b/arch/arm/cpu/armv8/u-boot-spl.lds
> index ef8af67e11c3..215cedd69a8c 100644
> --- a/arch/arm/cpu/armv8/u-boot-spl.lds
> +++ b/arch/arm/cpu/armv8/u-boot-spl.lds
> @@ -53,12 +53,7 @@ SECTIONS
>  
>  	. = ALIGN(8);
>  	__image_copy_end = .;
> -
> -	.end : {
> -		. = ALIGN(8);
> -		*(.__end)
> -	} >.sram
> -
> +	_end = .;
>  	_image_binary_end = .;
>  
>  	.bss : {
> diff --git a/arch/arm/cpu/u-boot-spl.lds b/arch/arm/cpu/u-boot-spl.lds
> index 9ed62395a9c5..eee463a1b1c6 100644
> --- a/arch/arm/cpu/u-boot-spl.lds
> +++ b/arch/arm/cpu/u-boot-spl.lds
> @@ -53,12 +53,8 @@ SECTIONS
>  		__rel_dyn_end = .;
>  	}
>  
> -	.end :
> -	{
> -		*(.__end)
> -	}
> -
>  	_image_binary_end = .;
> +	_end = .;
>  
>  	.bss __rel_dyn_start (OVERLAY) : {
>  		__bss_start = .;
> diff --git a/arch/arm/cpu/u-boot.lds b/arch/arm/cpu/u-boot.lds
> index 707b19795f08..2f50087f57a9 100644
> --- a/arch/arm/cpu/u-boot.lds
> +++ b/arch/arm/cpu/u-boot.lds
> @@ -166,11 +166,7 @@ SECTIONS
>  		__rel_dyn_end = .;
>  	}
>  
> -	.end :
> -	{
> -		*(.__end)
> -	}
> -
> +	_end = .;
>  	_image_binary_end = .;
>  
>  	/*
> diff --git a/arch/arm/lib/sections.c b/arch/arm/lib/sections.c
> index db5463b2bbbc..07efabaa7dc8 100644
> --- a/arch/arm/lib/sections.c
> +++ b/arch/arm/lib/sections.c
> @@ -23,4 +23,3 @@ char __secure_start[0] __section(".__secure_start");
>  char __secure_end[0] __section(".__secure_end");
>  char __secure_stack_start[0] __section(".__secure_stack_start");
>  char __secure_stack_end[0] __section(".__secure_stack_end");
> -char _end[0] __section(".__end");
> diff --git a/arch/arm/mach-aspeed/ast2600/u-boot-spl.lds b/arch/arm/mach-aspeed/ast2600/u-boot-spl.lds
> index ada6570d9712..9502a7384b53 100644
> --- a/arch/arm/mach-aspeed/ast2600/u-boot-spl.lds
> +++ b/arch/arm/mach-aspeed/ast2600/u-boot-spl.lds
> @@ -61,11 +61,7 @@ SECTIONS
>  		__rel_dyn_end = .;
>  	} > .nor
>  
> -	.end :
> -	{
> -		*(.__end)
> -	} > .nor
> -
> +	_end = .;
>  	_image_binary_end = .;
>  
>  	.bss : {
> diff --git a/arch/arm/mach-at91/arm926ejs/u-boot-spl.lds b/arch/arm/mach-at91/arm926ejs/u-boot-spl.lds
> index 1a8bf94dee0c..09cf838cf96e 100644
> --- a/arch/arm/mach-at91/arm926ejs/u-boot-spl.lds
> +++ b/arch/arm/mach-at91/arm926ejs/u-boot-spl.lds
> @@ -33,12 +33,7 @@ SECTIONS
>  
>  	. = ALIGN(4);
>  	__image_copy_end = .;
> -
> -	.end :
> -	{
> -		*(.__end)
> -	} >.sram
> -
> +	_end = .;
>  	_image_binary_end = .;
>  
>  	.bss :
> diff --git a/arch/arm/mach-at91/armv7/u-boot-spl.lds b/arch/arm/mach-at91/armv7/u-boot-spl.lds
> index 6ca725fc4ce0..460a91d93ec4 100644
> --- a/arch/arm/mach-at91/armv7/u-boot-spl.lds
> +++ b/arch/arm/mach-at91/armv7/u-boot-spl.lds
> @@ -40,12 +40,7 @@ SECTIONS
>  
>  	. = ALIGN(4);
>  	__image_copy_end = .;
> -
> -	.end :
> -	{
> -		*(.__end)
> -	} >.sram
> -
> +	_end = .;

Does this have any kind of consequence in terms of checking the offset of .end vs
the SRAM size ? (.sram)

>  	_image_binary_end = .;
>  
>  	.bss :



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