linux-kernel - Re: [PATCH 2/3] riscv: vdso.lds.S: merge .data section into .rodata section

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Message-ID: <ZMPMfMPoG/KnuWLN@xhacker>
Date:   Fri, 28 Jul 2023 22:11:08 +0800
From:   Jisheng Zhang <jszhang@...nel.org>
To:     Andrew Jones <ajones@...tanamicro.com>
Cc:     Paul Walmsley <paul.walmsley@...ive.com>,
        Palmer Dabbelt <palmer@...belt.com>,
        Albert Ou <aou@...s.berkeley.edu>,
        linux-riscv@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/3] riscv: vdso.lds.S: merge .data section into .rodata
 section

On Fri, Jul 28, 2023 at 02:57:03PM +0200, Andrew Jones wrote:
> On Thu, Jul 27, 2023 at 01:30:23AM +0800, Jisheng Zhang wrote:
> > The .data section doesn't need to be separate from .rodata section,
> > they are both readonly.
> > 
> > Signed-off-by: Jisheng Zhang <jszhang@...nel.org>
> > ---
> >  arch/riscv/kernel/vdso/vdso.lds.S | 15 +++++++--------
> >  1 file changed, 7 insertions(+), 8 deletions(-)
> > 
> > diff --git a/arch/riscv/kernel/vdso/vdso.lds.S b/arch/riscv/kernel/vdso/vdso.lds.S
> > index d43fd7c7dd11..671aa21769bc 100644
> > --- a/arch/riscv/kernel/vdso/vdso.lds.S
> > +++ b/arch/riscv/kernel/vdso/vdso.lds.S
> > @@ -29,7 +29,13 @@ SECTIONS
> >  	.eh_frame_hdr	: { *(.eh_frame_hdr) }		:text	:eh_frame_hdr
> >  	.eh_frame	: { KEEP (*(.eh_frame)) }	:text
> >  
> > -	.rodata		: { *(.rodata .rodata.* .gnu.linkonce.r.*) }
> > +	.rodata		: {
> > +		*(.rodata .rodata.* .gnu.linkonce.r.*)
> > +		*(.got.plt) *(.got)
> > +		*(.data .data.* .gnu.linkonce.d.*)
> > +		*(.dynbss)
> > +		*(.bss .bss.* .gnu.linkonce.b.*)
> 
> Looking at other architectures, it appears the last three lines of
> sections could be discarded, but I don't know enough about this to

Hi Andrew,

I checked x86, they still keep those sections. From another side,
even if those sections are not needed, removing unused sections could
be an independent patch, for safe reason or bisect reason.

Thanks


> state they should be.
> 
> Thanks,
> drew
> 
> 
> > +	}
> >  
> >  	/*
> >  	 * This linker script is used both with -r and with -shared.
> > @@ -44,13 +50,6 @@ SECTIONS
> >  	.alternative : {
> >  		*(.alternative)
> >  	}
> > -
> > -	.data		: {
> > -		*(.got.plt) *(.got)
> > -		*(.data .data.* .gnu.linkonce.d.*)
> > -		*(.dynbss)
> > -		*(.bss .bss.* .gnu.linkonce.b.*)
> > -	}
> >  }
> >  
> >  /*
> > -- 
> > 2.40.1
> >