[PATCH v4 15/22] ARM: linker script: create separate PT_LOAD segments for text, rodata, and data

[Ahmad Fatoum]

On 1/14/26 1:14 PM, Sascha Hauer wrote:
> Fix the linker scripts to generate three distinct PT_LOAD segments with
> correct permissions instead of combining .rodata with .data.
> 
> Before this fix, the linker auto-generated only two PT_LOAD segments:
> 1. Text segment (PF_R|PF_X)
> 2. Data segment (PF_R|PF_W) - containing .rodata, .data, .bss, etc.
> 
> With explicit PHDRS directives, we now generate three segments:
> 1. text segment (PF_R|PF_X): .text and related code sections
> 2. rodata segment (PF_R): .rodata and unwind tables
> 3. data segment (PF_R|PF_W): .data, .bss, and related sections
> 
> With this we can setup the MMU properly from outside the ELF binary.
> 
> 🤖 Generated with [Claude Code](https://claude.com/claude-code)
> 
> Co-Authored-By: Claude Sonnet 4.5 <noreply at anthropic.com>
> Signed-off-by: Sascha Hauer <s.hauer at pengutronix.de>

Reviewed-by: Ahmad Fatoum <a.fatoum at pengutronix.de>

> ---
>  arch/arm/lib32/barebox.lds.S | 35 +++++++++++++++++++++++------------
>  arch/arm/lib64/barebox.lds.S | 31 ++++++++++++++++++++-----------
>  2 files changed, 43 insertions(+), 23 deletions(-)
> 
> diff --git a/arch/arm/lib32/barebox.lds.S b/arch/arm/lib32/barebox.lds.S
> index c704dd6d70f3ab157ceb67dfb14760e03f2a5d62..c09899361599dfc8d50b38e35b68c08f48ea9913 100644
> --- a/arch/arm/lib32/barebox.lds.S
> +++ b/arch/arm/lib32/barebox.lds.S
> @@ -7,14 +7,23 @@
>  OUTPUT_FORMAT(BAREBOX_OUTPUT_FORMAT)
>  OUTPUT_ARCH(BAREBOX_OUTPUT_ARCH)
>  ENTRY(start)
> +
> +PHDRS
> +{
> +	text PT_LOAD FLAGS(5);		/* PF_R | PF_X */
> +	rodata PT_LOAD FLAGS(4);	/* PF_R */
> +	dynamic PT_DYNAMIC FLAGS(4);	/* PF_R */
> +	data PT_LOAD FLAGS(6);		/* PF_R | PF_W */
> +}
> +
>  SECTIONS
>  {
>  	. = 0x0;
> -	.image_start : { *(.__image_start) }
> +	.image_start : { *(.__image_start) } :text
>  
>  	. = ALIGN(4);
>  
> -	._text : { *(._text) }
> +	._text : { *(._text) } :text
>  	.text      :
>  	{
>  		_stext = .;
> @@ -27,7 +36,7 @@ SECTIONS
>  		KEEP(*(.text_exceptions*))
>  		__exceptions_stop = .;
>  		*(.text*)
> -	}
> +	} :text
>  	BAREBOX_BARE_INIT_SIZE
>  
>  	. = ALIGN(4096);
> @@ -35,7 +44,7 @@ SECTIONS
>  	.rodata : {
>  		*(.rodata*)
>  		RO_DATA_SECTION
> -	}
> +	} :rodata
>  
>  #ifdef CONFIG_ARM_UNWIND
>  	/*
> @@ -46,20 +55,22 @@ SECTIONS
>  		__start_unwind_idx = .;
>  		*(.ARM.exidx*)
>  		__stop_unwind_idx = .;
> -	}
> +	} :rodata
>  	.ARM.unwind_tab : {
>  		__start_unwind_tab = .;
>  		*(.ARM.extab*)
>  		__stop_unwind_tab = .;
> -	}
> +	} :rodata
>  #endif
> +	.dynamic : { *(.dynamic) } :rodata :dynamic
> +
>  	. = ALIGN(4096);
> +
>  	__end_rodata = .;
>  	_etext = .;
>  	_sdata = .;
>  
> -	. = ALIGN(4);
> -	.data : { *(.data*) }
> +	.data : { *(.data*) } :data
>  
>  	. = .;
>  
> @@ -69,12 +80,12 @@ SECTIONS
>  
>  	BAREBOX_EFI_RUNTIME
>  
> -	.image_end : { *(.__image_end) }
> +	.image_end : { *(.__image_end) } :data
>  
>  	. = ALIGN(4);
> -	.__bss_start :  { *(.__bss_start) }
> -	.bss : { *(.bss*) }
> -	.__bss_stop :  { *(.__bss_stop) }
> +	.__bss_start :  { *(.__bss_start) } :data
> +	.bss : { *(.bss*) } :data
> +	.__bss_stop :  { *(.__bss_stop) } :data
>  
>  #ifdef CONFIG_ARM_SECURE_MONITOR
>  	. = ALIGN(16);
> diff --git a/arch/arm/lib64/barebox.lds.S b/arch/arm/lib64/barebox.lds.S
> index 5ee5fbc3741e1f7644c00f9b37c0903c27704a3e..1ce2c67df03068e5328a41b394aa1bcbbe63c027 100644
> --- a/arch/arm/lib64/barebox.lds.S
> +++ b/arch/arm/lib64/barebox.lds.S
> @@ -6,14 +6,23 @@
>  OUTPUT_FORMAT(BAREBOX_OUTPUT_FORMAT)
>  OUTPUT_ARCH(BAREBOX_OUTPUT_ARCH)
>  ENTRY(start)
> +
> +PHDRS
> +{
> +	text PT_LOAD FLAGS(5);		/* PF_R | PF_X */
> +	rodata PT_LOAD FLAGS(4);	/* PF_R */
> +	dynamic PT_DYNAMIC FLAGS(4);	/* PF_R */
> +	data PT_LOAD FLAGS(6);		/* PF_R | PF_W */
> +}
> +
>  SECTIONS
>  {
>  	. = 0x0;
>  
> -	.image_start : { *(.__image_start) }
> +	.image_start : { *(.__image_start) } :text
>  
>  	. = ALIGN(4);
> -	._text : { *(._text) }
> +	._text : { *(._text) } :text
>  	.text      :
>  	{
>  		_stext = .;
> @@ -22,7 +31,7 @@ SECTIONS
>  		*(.text_bare_init*)
>  		__bare_init_end = .;
>  		*(.text*)
> -	}
> +	} :text
>  	BAREBOX_BARE_INIT_SIZE
>  
>  	. = ALIGN(4096);
> @@ -30,7 +39,9 @@ SECTIONS
>  	.rodata : {
>  		*(.rodata*)
>  		RO_DATA_SECTION
> -	}
> +	} :rodata
> +
> +	.dynamic : { *(.dynamic) } :rodata :dynamic
>  
>  	. = ALIGN(4096);
>  
> @@ -38,20 +49,18 @@ SECTIONS
>  	_etext = .;
>  	_sdata = .;
>  
> -	.data : { *(.data*) }
> -
> -	BAREBOX_RELOCATION_TABLE
> +	.data : { *(.data*) } :data
>  
>  	_edata = .;
>  
>  	BAREBOX_EFI_RUNTIME
>  
> -	.image_end : { *(.__image_end) }
> +	.image_end : { *(.__image_end) } :data
>  
>  	. = ALIGN(4);
> -	.__bss_start :  { *(.__bss_start) }
> -	.bss : { *(.bss*) }
> -	.__bss_stop :  { *(.__bss_stop) }
> +	.__bss_start :  { *(.__bss_start) } :data
> +	.bss : { *(.bss*) } :data
> +	.__bss_stop :  { *(.__bss_stop) } :data
>  	_end = .;
>  	_barebox_image_size = __bss_start;
>  }
> 

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