Re: [Xen-devel] [PATCH v6 17/24] build_id: Provide ld-embedded build-ids

[Julien Grall <julien.grall@xxxxxxx>]

Hi Konrad,

On 07/04/16 04:49, Konrad Rzeszutek Wilk wrote:
> This patch enables the Elf to be built with the build-id
> and provide in the Xen hypervisor the code to extract it.
>
> One can also retrieve the value of the build-id by doing
> 'readelf -n xen-syms'.
>
> For EFI builds we re-use the same build-id that the xen-syms
> was built with.
>
> The version of ld that first implemented --build-id is v2.18.
> We check for to see if the linker supports the --build-id
> parameter and if so use it.
>
> For x86 we have two binaries - the xen-syms and the xen - an
> smaller version with lots of sections removed. To make it possible
> for readelf -n xen we also modify mkelf32 and xen.lds.S to include
> the PT_NOTE ELF section.
>
> The EFI binary is more complicated. Having any non-recognizable
> sections (.note, .data.note, etc) causes the boot to hang.
> Moving the .note in the .data section makes it work. It is also
> worth noting that the PE/COFF does not have any "comment"
> sections to the author.
>
> Lastly, we MUST call --binary-id=sha1 on all linker invocation so that
> symbol offsets don't changes (which means we have multiple binary
> ids - except that the last one is the final one). Without this change,
> the symbol table embedded in Xen are incorrect - some of the values it
> contains are offset by the size of the included build id.
> This obviously causes problems when resolving symbols.
>
> Suggested-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
> Signed-off-by: Martin Pohlack <mpohlack@xxxxxxxxx>
> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
For the ARM bits:

Acked-by: Julien Grall <julien.grall@xxxxxxx>

Regards,

--
Julien Grall

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel