Re: [PATCH v4 19/22] riscv: linker script: create separate PT_LOAD segments for text, rodata, and data

[Ahmad Fatoum <a.fatoum@pengutronix.de>]

On 1/14/26 1:14 PM, Sascha Hauer wrote:
> Fix the linker script 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 related read-only sections
> 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.
> 
> Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

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

> ---
>  arch/riscv/lib/barebox.lds.S | 38 +++++++++++++++++++++++++-------------
>  1 file changed, 25 insertions(+), 13 deletions(-)
> 
> diff --git a/arch/riscv/lib/barebox.lds.S b/arch/riscv/lib/barebox.lds.S
> index 03b3a967193cfee1c67b96632cf972a553e8bec4..0cfa4bff57920bfaed822cb62c553c49f543994c 100644
> --- a/arch/riscv/lib/barebox.lds.S
> +++ b/arch/riscv/lib/barebox.lds.S
> @@ -16,14 +16,23 @@
>  OUTPUT_ARCH(BAREBOX_OUTPUT_ARCH)
>  ENTRY(start)
>  OUTPUT_FORMAT(BAREBOX_OUTPUT_FORMAT)
> +
> +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 = .;
> @@ -35,44 +44,47 @@ SECTIONS
>  		KEEP(*(.text_exceptions*))
>  		__exceptions_stop = .;
>  		*(.text*)
> -	}
> +	} :text
>  	BAREBOX_BARE_INIT_SIZE
>  
> -	. = ALIGN(4);
> +	. = ALIGN(4096);
>  	__start_rodata = .;
>  	.rodata : {
>  		*(.rodata*)
>  		RO_DATA_SECTION
> -	}
> +	} :rodata
> +
> +	.dynamic : { *(.dynamic) } :rodata :dynamic
>  
>  	__end_rodata = .;
>  	_etext = .;
>  	_sdata = .;
>  
> -	. = ALIGN(4);
> -	.data : { *(.data*) }
> +	. = ALIGN(4096);
> +
> +	.data : { *(.data*) } :data
>  
>  	/DISCARD/ : { *(.rela.plt*) }
>  	.rela.dyn : {
>  		__rel_dyn_start = .;
>  		*(.rel*)
>  		__rel_dyn_end = .;
> -	}
> +	} :data
>  
>  	.dynsym : {
>  		__dynsym_start = .;
>  		*(.dynsym)
>  		__dynsym_end = .;
> -	}
> +	} :data
>  
>  	_edata = .;
>  
> -	.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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