Re: [PATCH] uselib: default depending if libc5 was used

From: Josh Triplett
Date: Fri Nov 27 2015 - 04:33:28 EST


On Fri, Nov 27, 2015 at 11:11:26AM +0200, Riku Voipio wrote:
> uselib hasn't been used since libc5; glibc does not use it.
> Deprecate uselib a bit more, by making the default y only
> if libc5 was widely used on the plaform.
>
> This makes arm64 kernel built with defconfig slighly smaller
>
> bloat-o-meter:
> add/remove: 0/3 grow/shrink: 0/2 up/down: 0/-1390 (-1390)
> function old new delta
> kernel_config_data 18164 18162 -2
> uselib_flags 20 - -20
> padzero 216 192 -24
> sys_uselib 380 - -380
> load_elf_library 964 - -964
>
> Signed-off-by: Riku Voipio <riku.voipio@xxxxxxxxxx>
> Cc: Josh Triplett <josh@xxxxxxxxxxxxxxxx>

Seems sensible. Can you also make it only "default y" on 32-bit x86,
not 64-bit x86, since the latter never had libc5?

With that change:
Reviewed-by: Josh Triplett <josh@xxxxxxxxxxxxxxxx>

> init/Kconfig | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/init/Kconfig b/init/Kconfig
> index c24b6f7..bef326d 100644
> --- a/init/Kconfig
> +++ b/init/Kconfig
> @@ -285,7 +285,7 @@ config FHANDLE
>
> config USELIB
> bool "uselib syscall"
> - default y
> + def_bool ALPHA || M68K || SPARC || X86
> help
> This option enables the uselib syscall, a system call used in the
> dynamic linker from libc5 and earlier. glibc does not use this
> --
> 2.6.2
>
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