From: "Maciej W. Rozycki" <macro@orcam.me.uk>
To: YunQiang Su <syq@gcc.gnu.org>
Cc: Nick Clifton <nickc@redhat.com>,
binutils@sourceware.org, xry111@xry111.site
Subject: Re: [PATCH v4] MIPS/Gas: Disallow branch to absolute address for PIC
Date: Tue, 6 Feb 2024 19:20:14 +0000 (GMT) [thread overview]
Message-ID: <alpine.DEB.2.21.2402061910440.2376@angie.orcam.me.uk> (raw)
In-Reply-To: <20240206170538.2937169-1-syq@gcc.gnu.org>
On Wed, 7 Feb 2024, YunQiang Su wrote:
> The asm code like
> b (0)
> will generate binary like:
>
> 00000000 <.text>:
> 0: 1000ffff b 0x0
> 0: R_MIPS_PC16 *ABS*
> 4: 00000000 nop
> If this object is linked into an PIC/PIC dynamic executable,
> this branch instruction will jump to a wrong address, with low
> 16bit unset.
NAK, `mips_pic' may be set to SVR4_PIC and still produce de facto non-PIC
code, as per the original SVR4 MIPS ABI (with lazy binding stubs rather
than PLT). We continue supporting this mode.
Originally NO_PIC was intended for bare metal code only, statically
linked only, which was later extended to Linux, etc. with the addition of
PLT and copy reloc support.
PR31343 has to be sorted in the linker.
Maciej
next prev parent reply other threads:[~2024-02-06 19:20 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-02-06 17:05 YunQiang Su
2024-02-06 19:20 ` Maciej W. Rozycki [this message]
2024-02-07 4:37 ` YunQiang Su
2024-02-07 11:03 ` Maciej W. Rozycki
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