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Re: [PATCH][RFC] aarch64: fix start code for static pie
- From: Szabolcs Nagy <szabolcs dot nagy at arm dot com>
- To: GNU C Library <libc-alpha at sourceware dot org>
- Cc: nd at arm dot com, "H.J. Lu" <hjl dot tools at gmail dot com>
- Date: Mon, 18 Dec 2017 10:22:00 +0000
- Subject: Re: [PATCH][RFC] aarch64: fix start code for static pie
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On 24/11/17 12:39, Szabolcs Nagy wrote:
> 2017-11-24 Szabolcs Nagy <firstname.lastname@example.org>
> * sysdeps/aarch64/start.S (_start): Handle PIC && !SHARED case.
committed with updated commit message:
There are three flavors of the crt startup code:
1) crt1.o used for non-pie,
2) Scrt1.o used for dynamic linked pie (dynamic linker relocates),
3) rcrt1.o used for static linked pie (self relocation is needed)
In the --enable-static-pie case crt1.o is built with -DPIC and in case
of static linking it interposes _dl_relocate_static_pie in libc to
avoid self relocation.
Scrt1.o is built with -DPIC -DSHARED and it relies on GOT entries that
the static linker cannot relax and thus need relocation before the
start code is executed, so rcrt1.o needs separate implementation.
This implementation does not work for .text > 4G position independent
executables, which is fine since the toolchain does not support
-mcmodel=large with -fPIE.
Tests pass with ld/22269 and ld/22263 binutils bugs fixed.
* sysdeps/aarch64/start.S (_start): Handle PIC && !SHARED case.