Drop explicit --hash-style= setting for new

[PATCH 0/3] Drop explicit --hash-style= setting for new

Posted by Xi Ruoyao 11 months, 2 weeks ago

For riscv, csky, and LoongArch, GNU hash had already become the de-facto
standard when they borned, so there's no Glibc/Musl releases for them
without GNU hash support, and the traditional SysV hash is just wasting
space for them.

Remove those settings and follow the distro toolchain default, which is
likely --hash-style=gnu.  In the past it could break vDSO self tests,
but now the issue has been addressed by commit
e0746bde6f82 ("selftests/vDSO: support DT_GNU_HASH").

Xi Ruoyao (3):
  riscv: vDSO: Remove --hash-style=both
  csky: vDSO: Remove --hash-style=both
  LoongArch: vDSO: Remove --hash-style=sysv

 arch/csky/kernel/vdso/Makefile  | 2 +-
 arch/loongarch/vdso/Makefile    | 2 +-
 arch/riscv/kernel/vdso/Makefile | 2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)

-- 
2.48.1

Ping: [PATCH 0/3] Drop explicit --hash-style= setting for new

Posted by Xi Ruoyao 11 months, 1 week ago

Ping.

On Mon, 2025-02-24 at 19:20 +0800, Xi Ruoyao wrote:
> For riscv, csky, and LoongArch, GNU hash had already become the de-
> facto
> standard when they borned, so there's no Glibc/Musl releases for them
> without GNU hash support, and the traditional SysV hash is just
> wasting
> space for them.
> 
> Remove those settings and follow the distro toolchain default, which
> is
> likely --hash-style=gnu.  In the past it could break vDSO self tests,
> but now the issue has been addressed by commit
> e0746bde6f82 ("selftests/vDSO: support DT_GNU_HASH").
> 
> Xi Ruoyao (3):
>   riscv: vDSO: Remove --hash-style=both
>   csky: vDSO: Remove --hash-style=both
>   LoongArch: vDSO: Remove --hash-style=sysv
> 
>  arch/csky/kernel/vdso/Makefile  | 2 +-
>  arch/loongarch/vdso/Makefile    | 2 +-
>  arch/riscv/kernel/vdso/Makefile | 2 +-
>  3 files changed, 3 insertions(+), 3 deletions(-)
> 

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

Re: Ping: [PATCH 0/3] Drop explicit --hash-style= setting for new

Posted by Guo Ren 11 months ago

On Wed, Mar 5, 2025 at 9:27 PM Xi Ruoyao <xry111@xry111.site> wrote:
>
> Ping.
>
> On Mon, 2025-02-24 at 19:20 +0800, Xi Ruoyao wrote:
> > For riscv, csky, and LoongArch, GNU hash had already become the de-
> > facto
> > standard when they borned, so there's no Glibc/Musl releases for them
> > without GNU hash support, and the traditional SysV hash is just
> > wasting
> > space for them.
> >
> > Remove those settings and follow the distro toolchain default, which
> > is
> > likely --hash-style=gnu.  In the past it could break vDSO self tests,
> > but now the issue has been addressed by commit
> > e0746bde6f82 ("selftests/vDSO: support DT_GNU_HASH").
> >
> > Xi Ruoyao (3):
> >   riscv: vDSO: Remove --hash-style=both
The patch's comment is incorrect; when I removed --hash-style=both,
the output still contained the HASH, and no space was saved.

--hash-style=both and after the patch are the same:
Section Headers:
  [Nr] Name              Type             Address           Offset
       Size              EntSize          Flags  Link  Info  Align
  [ 0]                   NULL             0000000000000000  00000000
       0000000000000000  0000000000000000           0     0     0
  [ 1] .hash             HASH             0000000000000120  00000120
       000000000000003c  0000000000000004   A       3     0     8
  [ 2] .gnu.hash         GNU_HASH         0000000000000160  00000160
       0000000000000044  0000000000000000   A       3     0     8

But, --hash-style=gnu could save space:
Section Headers:
  [Nr] Name              Type             Address           Offset
       Size              EntSize          Flags  Link  Info  Align
  [ 0]                   NULL             0000000000000000  00000000
       0000000000000000  0000000000000000           0     0     0
  [ 1] .gnu.hash         GNU_HASH         0000000000000120  00000120
       0000000000000044  0000000000000000   A       2     0     8


Here is my GCC VERSION:
Using built-in specs.
COLLECT_GCC=/rvhome/ren.guo/source/toolchain/rv64lp64/bin/riscv64-unknown-linux-gnu-gcc
COLLECT_LTO_WRAPPER=/rvhome/ren.guo/source/toolchain/rv64lp64/bin/../libexec/gcc/riscv64-unknown-linux-gnu/13.2.0/lto-wrapper
Target: riscv64-unknown-linux-gnu
Configured with:
/home/runner/work/riscv-gnu-toolchain/riscv-gnu-toolchain/gcc/configure
--target=riscv64-unknown-linux-gnu --prefix=/opt/riscv
--with-sysroot=/opt/riscv/sysroot --with-pkgversion=
--with-system-zlib --enable-shared --enable-tls
--enable-languages=c,c++,fortran --disable-libmudflap --disable-libssp
--disable-libquadmath --disable-libsanitizer --disable-nls
--disable-bootstrap --src=.././gcc --disable-default-pie
--disable-multilib --with-abi=lp64d --with-arch=rv64gc
--with-tune=rocket --with-isa-spec=20191213 'CFLAGS_FOR_TARGET=-O2
-mcmodel=medlow' 'CXXFLAGS_FOR_TARGET=-O2    -mcmodel=medlow'
Thread model: posix
Supported LTO compression algorithms: zlib
gcc version 13.2.0 ()

So, do you mean "--hash-style=gnu"?

> >   csky: vDSO: Remove --hash-style=both
> >   LoongArch: vDSO: Remove --hash-style=sysv
> >
> >  arch/csky/kernel/vdso/Makefile  | 2 +-
> >  arch/loongarch/vdso/Makefile    | 2 +-
> >  arch/riscv/kernel/vdso/Makefile | 2 +-
> >  3 files changed, 3 insertions(+), 3 deletions(-)
> >
>
> --
> Xi Ruoyao <xry111@xry111.site>
> School of Aerospace Science and Technology, Xidian University



-- 
Best Regards
 Guo Ren

Re: Ping: [PATCH 0/3] Drop explicit --hash-style= setting for new

Posted by Xi Ruoyao 10 months, 2 weeks ago

On Mon, 2025-03-10 at 10:13 +0800, Guo Ren wrote:
> On Wed, Mar 5, 2025 at 9:27 PM Xi Ruoyao <xry111@xry111.site> wrote:
> > 
> > Ping.
> > 
> > On Mon, 2025-02-24 at 19:20 +0800, Xi Ruoyao wrote:
> > > For riscv, csky, and LoongArch, GNU hash had already become the de-
> > > facto
> > > standard when they borned, so there's no Glibc/Musl releases for them
> > > without GNU hash support, and the traditional SysV hash is just
> > > wasting
> > > space for them.
> > > 
> > > Remove those settings and follow the distro toolchain default, which
> > > is
> > > likely --hash-style=gnu.  In the past it could break vDSO self tests,
> > > but now the issue has been addressed by commit
> > > e0746bde6f82 ("selftests/vDSO: support DT_GNU_HASH").
> > > 
> > > Xi Ruoyao (3):
> > >   riscv: vDSO: Remove --hash-style=both
> The patch's comment is incorrect; when I removed --hash-style=both,
> the output still contained the HASH, and no space was saved.

The idea is following the distro toolchain default (which can be
configured building binutils).

If the distro toolchain default is gnu, we'll use gnu.

If the distro toolchain default is both, the distro is already wasting
space everywhere for (a) some bizarre applications depending on DT_HASH
for some bizzare reason; or (b) an oversight.

In the case of (a) the bizarre application may needs DT_HASH in vDSO as
well, and in the case of (b) it should be fixed for the entire distro,
not only vDSO, for example what we are doing for AOSC:
https://github.com/AOSC-Dev/aosc-os-abbs/pull/9531

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