Re: [PATCH v3 6/9] x86/entry/vdso: include GNU_PROPERTY and GNU_STACK PHDRs

[Andrew Cooper <andrew.cooper3@citrix.com>]

On 12/11/2025 8:22 pm, H. Peter Anvin wrote:
>  arch/x86/entry/vdso/common/vdso-layout.lds.S | 51 +++++++++++---------
>  1 file changed, 28 insertions(+), 23 deletions(-)
>
> diff --git a/arch/x86/entry/vdso/common/vdso-layout.lds.S b/arch/x86/entry/vdso/common/vdso-layout.lds.S
> index ec1ac191a057..696bacb99ed8 100644
> --- a/arch/x86/entry/vdso/common/vdso-layout.lds.S
> +++ b/arch/x86/entry/vdso/common/vdso-layout.lds.S
> @@ -26,7 +26,7 @@ SECTIONS
>  
>  	. = SIZEOF_HEADERS;
>  
> -	.hash		: { *(.hash) }			:text
> +	.hash		: { *(.hash) }		:text
>  	.gnu.hash	: { *(.gnu.hash) }
>  	.dynsym		: { *(.dynsym) }
>  	.dynstr		: { *(.dynstr) }
> @@ -34,7 +34,7 @@ SECTIONS
>  	.gnu.version_d	: { *(.gnu.version_d) }
>  	.gnu.version_r	: { *(.gnu.version_r) }
>  
> -	.dynamic	: { *(.dynamic) }		:text	:dynamic
> +	.dynamic	: { *(.dynamic) }	:text :dynamic
>  
>  	.rodata		: {
>  		*(.rodata*)
> @@ -45,31 +45,28 @@ SECTIONS
>  		*(.bss*)
>  		*(.dynbss*)
>  		*(.gnu.linkonce.b.*)
> -	}						:text
> +	}					:text
>  
> -	/*
> -	 * Discard .note.gnu.property sections which are unused and have
> -	 * different alignment requirement from vDSO note sections.
> -	 */
> -	/DISCARD/ : {
> +	.note.gnu.property : {
>  		*(.note.gnu.property)
> -	}
> -	.note		: { *(.note.*) }		:text	:note
> -
> -	.eh_frame_hdr	: { *(.eh_frame_hdr) }		:text	:eh_frame_hdr
> -	.eh_frame	: { KEEP (*(.eh_frame)) }	:text
> +	}					:text :note :gnu_property
> +	.note		: {
> +		*(.note*)
> +	}					:text :note
>  
> +	.eh_frame_hdr	: { *(.eh_frame_hdr) }	:text :eh_frame_hdr
> +	.eh_frame	: {
> +		KEEP (*(.eh_frame))
> +		*(.eh_frame.*)
> +	}					:text
>  
>  	/*
>  	 * Text is well-separated from actual data: there's plenty of
>  	 * stuff that isn't used at runtime in between.
> -	 */
> -
> +	*/
>  	.text		: {
>  		*(.text*)
> -	}						:text	=0x90909090,
> -
> -
> +	}					:text	=0x90909090
>  

Almost all of these hunks look to be whitespace changes only.  Was that
intentional?  It certainly makes it harder to read.

>  	.altinstructions	: { *(.altinstructions) }	:text
>  	.altinstr_replacement	: { *(.altinstr_replacement) }	:text
> @@ -87,15 +84,23 @@ SECTIONS
>   * Very old versions of ld do not recognize this name token; use the constant.
>   */
>  #define PT_GNU_EH_FRAME	0x6474e550
> +#define PT_GNU_STACK	0x6474e551
> +#define PT_GNU_PROPERTY	0x6474e553
>  
>  /*
>   * We must supply the ELF program headers explicitly to get just one
>   * PT_LOAD segment, and set the flags explicitly to make segments read-only.
> - */
> +*/

This looks like it wants undoing too.

That said, I do strongly agree with the reasoning behind this patch.

~Andrew