From: "H.J. Lu" <hjl.tools@gmail.com>
To: Jan Beulich <jbeulich@suse.com>
Cc: Binutils <binutils@sourceware.org>
Subject: Re: [PATCH] elf/x86-64: Subtract __ImageBase for R_AMD64_IMAGEBASE
Date: Tue, 23 Feb 2021 05:31:28 -0800 [thread overview]
Message-ID: <CAMe9rOpk+jHx++pTLiDye6duP_mNzeGzHSMsB_XgjYkRPB_b1w@mail.gmail.com> (raw)
In-Reply-To: <77fa2de7-91ad-5f33-ea60-91c097d1c8ff@suse.com>
On Tue, Feb 23, 2021 at 5:15 AM Jan Beulich <jbeulich@suse.com> wrote:
>
> On 23.02.2021 13:15, H.J. Lu via Binutils wrote:
> > When linking PE/x86-64 inputs to generate ELF executable, we need to
> > subtract __ImageBase, aka __executable_start, for R_AMD64_IMAGEBASE
> > relocation.
>
> Do you really mean PE/x86-64, not the respective COFF objects? In the
What is the difference? How should I call object files generated by
Microsoft Visual Studio?
> description this may not matter much, but since there's at least one
> code comment also saying so, which may confuse readers, I'd like to
> understand this.
>
> Also, in how far is this x86-64-specific?
I don't know.
> > --- a/ld/testsuite/ld-x86-64/pe-x86-64-1.od
> > +++ b/ld/testsuite/ld-x86-64/pe-x86-64-1.od
> > @@ -2,6 +2,7 @@
> > .*: +file format .*
> >
> > SYMBOL TABLE:
> > +0+400000 g .text\$mn 0000000000000000 __executable_start
> > 0+401000 g .text\$mn 0000000000000000 getaddr1
> > 0+401020 g .text\$mn 0000000000000000 begin
> > 0+403014 g .bss 0000000000000000 __bss_start
>
> I don't think this artifical symbol should appear in the symbol
This symbol is generated by linker. It should be harmless.
> table. I also wonder what the consequences are if a set of linked
> object files specifies a symbol of this name.
__executable_start is generated by linker. If __ImageBase is
defined to another value, that value will be used as image base.
--
H.J.
next prev parent reply other threads:[~2021-02-23 13:32 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-23 12:15 H.J. Lu
2021-02-23 13:15 ` Jan Beulich
2021-02-23 13:31 ` H.J. Lu [this message]
2021-02-23 14:10 ` Jan Beulich
2021-02-23 14:47 ` H.J. Lu
2021-02-23 15:02 ` Jan Beulich
2021-02-23 15:07 ` H.J. Lu
2021-02-23 15:11 ` Jan Beulich
2021-02-23 17:50 ` [PATCH v2] " H.J. Lu
2021-02-25 2:09 ` Alan Modra
2021-02-28 2:38 ` [PATCH v3] " H.J. Lu
2021-03-01 12:19 ` Alan Modra
2021-03-01 13:44 ` H.J. Lu
2021-03-04 13:14 ` Alan Modra
2021-03-04 13:54 ` [PATCH v4] " H.J. Lu
2021-03-05 5:17 ` Alan Modra
2021-03-05 5:29 ` H.J. Lu
2021-03-05 13:57 ` Alan Modra
2021-03-05 18:26 ` [PATCH v5] " H.J. Lu
2021-03-06 0:11 ` Alan Modra
2021-03-06 1:00 ` [PATCH v6] " H.J. Lu
2021-03-07 4:16 ` Alan Modra
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