From: Florian Weimer <fweimer@redhat.com>
To: "H.J. Lu" <hjl.tools@gmail.com>
Cc: Szabolcs Nagy <nsz@port70.net>, Jan Beulich <JBeulich@suse.com>,
Rich Felker <dalias@libc.org>,
Binutils <binutils@sourceware.org>,
gnu-gabi@sourceware.org
Subject: Re: RFC: Add SHT_GNU_PHDRS
Date: Mon, 01 Jan 2018 00:00:00 -0000 [thread overview]
Message-ID: <87r2hfqes1.fsf@oldenburg.str.redhat.com> (raw)
In-Reply-To: <CAMe9rOrATHE+Hv2NScV4b2qg3xh_tqJgz7B0kZmurkbZ2Ld4aA@mail.gmail.com> (H. J. Lu's message of "Thu, 27 Sep 2018 05:54:05 -0700")
* H. J. Lu:
> On Thu, Sep 27, 2018 at 5:42 AM, Florian Weimer <fweimer@redhat.com> wrote:
>> * H. J. Lu:
>>
>>> On Thu, Sep 27, 2018 at 3:35 AM, Szabolcs Nagy <nsz@port70.net> wrote:
>>>> an alloc .phdr section covering the program headers solves
>>>> this problem. if sections are not required for segments
>>>> then simply the linker should ensure that there is always
>>>> a load segment covering the program headers, possibly
>>>> without containing any sections, however elf says
>>>> "An object file segment contains one or more sections".
>>>>
>>>> i don't understand why a zero-size section is enough, what
>>>> if phdr > pagesize? will that get covered by the load
>>>> segment that is created for the zero-size section?
>>>
>>> Linker must keep this zero-size section in output and
>>> create a PT_LOAD segment to cover it even if it is
>>> the only SHF_ALLOC section in the PT_LOAD segment.
>>
>> Based on Szabolcs' comment, I don't think the section can be zero-sized.
>>
>
> Why can't we put a zero-size section in a PT_LOAD segment?
> Of course, we need to change linker to do it.
I'm now under the impression that the bits that are PT_LOAD'ed all need
to be covered by (allocated) sections. A zero-sized section doesn't
cover anything, so it doesn't address this requirement of the ELF
specification.
Thanks,
Florian
next prev parent reply other threads:[~2018-09-27 12:57 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-01 0:00 H.J. Lu
2018-01-01 0:00 ` Carlos O'Donell
2018-01-01 0:00 ` H.J. Lu
[not found] ` <CAORpzuOWtHeqBLEE+MMN4-TZyp6Z1r-MdmyNv7Zj-BhxMstr=g@mail.gmail.com>
2018-01-01 0:00 ` H.J. Lu
2018-01-01 0:00 ` Florian Weimer
2018-01-01 0:00 ` Jan Beulich
2018-01-01 0:00 ` Florian Weimer
2018-01-01 0:00 ` Szabolcs Nagy
2018-01-01 0:00 ` H.J. Lu
2018-01-01 0:00 ` Florian Weimer
2018-01-01 0:00 ` H.J. Lu
2018-01-01 0:00 ` Florian Weimer [this message]
2018-01-01 0:00 ` Carlos O'Donell
2018-01-01 0:00 ` Cary Coutant
2018-01-01 0:00 ` H.J. Lu
2018-01-01 0:00 ` Rich Felker
2018-01-01 0:00 ` H.J. Lu
2018-01-01 0:00 ` Carlos O'Donell
2018-01-01 0:00 ` H.J. Lu
2018-01-01 0:00 ` Carlos O'Donell
2018-01-01 0:00 ` Michael Matz
2018-01-01 0:00 ` Florian Weimer
2018-01-01 0:00 ` Michael Matz
2018-01-01 0:00 ` Florian Weimer
2018-01-01 0:00 ` Cary Coutant
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