Re: [PATCH-next v4] arm32: enable HAVE_LD_DEAD_CODE_DATA_ELIMINATION

[liuyuntao (F)]

Gentle ping

On 2024/3/20 1:12, Ard Biesheuvel wrote:
> On Sat, 16 Mar 2024 at 03:44, Yuntao Liu <liuyuntao12@xxxxxxxxxx> wrote:
> > The current arm32 architecture does not yet support the
> > HAVE_LD_DEAD_CODE_DATA_ELIMINATION feature. arm32 is widely used in
> > embedded scenarios, and enabling this feature would be beneficial for
> > reducing the size of the kernel image.
> >
> > In order to make this work, we keep the necessary tables by annotating
> > them with KEEP, also it requires further changes to linker script to KEEP
> > some tables and wildcard compiler generated sections into the right place.
> > When using ld.lld for linking, KEEP is not recognized within the OVERLAY
> > command, and Ard proposed a concise method to solve this problem.
> >
> > It boots normally with defconfig, vexpress_defconfig and tinyconfig.
> >
> > The size comparison of zImage is as follows:
> > defconfig       vexpress_defconfig      tinyconfig
> > 5137712         5138024                 424192          no dce
> > 5032560         4997824                 298384          dce
> > 2.0%            2.7%                    29.7%           shrink
> >
> > When using smaller config file, there is a significant reduction in the
> > size of the zImage.
> >
> > We also tested this patch on a commercially available single-board
> > computer, and the comparison is as follows:
> > a15eb_config
> > 2161384         no dce
> > 2092240         dce
> > 3.2%            shrink
> >
> > The zImage size has been reduced by approximately 3.2%, which is 70KB on
> > 2.1M.
> >
> > Signed-off-by: Yuntao Liu <liuyuntao12@xxxxxxxxxx>
> > Tested-by: Arnd Bergmann <arnd@xxxxxxxx>
> > Reviewed-by: Arnd Bergmann <arnd@xxxxxxxx>
>
> Reviewed-by: Ard Biesheuvel <ardb@xxxxxxxxxx>