linux-kernel - Re: [PATCH 4/5] LoongArch: Stop using undocumented assembler options

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Date:   Thu, 28 Jul 2022 18:58:40 +0800
From:   Xi Ruoyao <xry111@...111.site>
To:     Youling Tang <tangyouling@...ngson.cn>, loongarch@...ts.linux.dev
Cc:     linux-kernel@...r.kernel.org, WANG Xuerui <kernel@...0n.name>,
        Huacai Chen <chenhuacai@...nel.org>
Subject: Re: [PATCH 4/5] LoongArch: Stop using undocumented assembler options

On Thu, 2022-07-28 at 17:46 +0800, Youling Tang wrote:
> 
> On 07/28/2022 12:29 AM, Xi Ruoyao wrote:
> > Now we can handle GOT and GOT-based relocations properly, remove the
> > undocumented `-Wa,-mla-{global,local}-with-{pcrel,abs}` assembler
> > hacks.
> > 
> > Adjust assembly code to explicitly use "la.pcrel" where necessary.
> > 
> > Signed-off-by: Xi Ruoyao <xry111@...111.site>
> > ---
> >  arch/loongarch/Makefile      |  5 +----
> >  arch/loongarch/kernel/head.S | 10 +++++-----
> >  2 files changed, 6 insertions(+), 9 deletions(-)
> > 
> > diff --git a/arch/loongarch/Makefile b/arch/loongarch/Makefile
> > index 039dcc4fe1f3..9552c7880d34 100644
> > --- a/arch/loongarch/Makefile
> > +++ b/arch/loongarch/Makefile
> > @@ -40,10 +40,7 @@ endif
> > 
> >  cflags-y                       += -G0 -pipe -msoft-float
> >  LDFLAGS_vmlinux                        += -G0 -static -n -nostdlib
> > -KBUILD_AFLAGS_KERNEL           += -Wa,-mla-global-with-pcrel
> > -KBUILD_CFLAGS_KERNEL           += -Wa,-mla-global-with-pcrel
> > -KBUILD_AFLAGS_MODULE           += -Wa,-mla-global-with-abs
> > -KBUILD_CFLAGS_MODULE           += -fplt -Wa,-mla-global-with-abs,-
> > mla-local-with-abs
> > +KBUILD_CFLAGS_MODULE           += -fplt
> 
> The -fplt flag may be removed, the compiler defaults to -fplt if not
> specified (riscv is also not manually specified as -fplt).

Will remove explicit -fplt in V2.

By the way, how do you think about "-G0"?  It does not have any effect
now because the toolchain does not attempt to use sbss/sdata sections.
Do we have any plan to add sbss and sdata support in the toolchain?


-- 
Xi Ruoyao <xry111@...111.site>
School of Aerospace Science and Technology, Xidian University