From: "H.J. Lu" <hjl.tools@gmail.com>
To: Fangrui Song <i@maskray.me>
Cc: Binutils <binutils@sourceware.org>
Subject: Re: [PATCH] ELF: Don't check relocations in non-loaded, non-alloced sections
Date: Tue, 2 Jun 2020 18:29:16 -0700 [thread overview]
Message-ID: <CAMe9rOqtub-8Cu=bQ=EThXP_-SM3X=Fo6S0qHcZcSykR-tftmA@mail.gmail.com> (raw)
In-Reply-To: <MWHPR12MB14567E24AED5430AAE2497A8CB880@MWHPR12MB1456.namprd12.prod.outlook.com>
On Tue, Jun 2, 2020 at 5:06 PM Fangrui Song <i@maskray.me> wrote:
>
> I haven't really read the patch, but just wanted to express a point.
> It is sometimes useful to check relocations even for a non-SHF_ALLOC
> section. For example, a PC relative relocation type does not make
> sense from a non-SHF_ALLOC section referencing a SHF_ALLOC section.
>
> Conceptually, even if a non-SHF_ALLOC is loaded as part of the memory
> image, the distance between it and a SHF_ALLOC section may not be a
> constant, so the linker cannot reasonably resolve the relocation.
>
Since non-SHF_ALLOC sections have no impact on run-time behavior,
ld.so ignores dynamic relocations on non-SHF_ALLOC section. In
checking phase, relocations on non-SHF_ALLOC section shouldn't
alter other relocatitons against the same symbol. When resolving
such relocations, linker should ignore any relocation errors for such
relocations.
--
H.J.
next prev parent reply other threads:[~2020-06-03 1:29 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-02 20:38 H.J. Lu
2020-06-03 0:05 ` Fangrui Song
[not found] ` <MWHPR12MB14567E24AED5430AAE2497A8CB880@MWHPR12MB1456.namprd12.prod.outlook.com>
2020-06-03 1:29 ` H.J. Lu [this message]
2020-06-03 16:48 ` V2 " H.J. Lu
2020-06-03 18:55 ` V3 " H.J. Lu
2020-06-04 7:47 ` Alan Modra
2020-06-04 11:24 ` V4 " H.J. Lu
2020-06-04 12:41 ` Alan Modra
2020-06-05 3:07 ` Alan Modra
2020-06-05 12:32 ` [PATCH] bfin: Skip non SEC_ALLOC section H.J. Lu
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