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x86: Update _dl_tlsdesc_dynamic to preserve caller-saved registers

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Compiler generates the following instruction sequence for GNU2 dynamic
TLS access:

	leaq	tls_var@TLSDESC(%rip), %rax
	call	*tls_var@TLSCALL(%rax)

or

	leal	tls_var@TLSDESC(%ebx), %eax
	call	*tls_var@TLSCALL(%eax)

CALL instruction is transparent to compiler which assumes all registers,
except for EFLAGS and RAX/EAX, are unchanged after CALL.  When
_dl_tlsdesc_dynamic is called, it calls __tls_get_addr on the slow
path.  __tls_get_addr is a normal function which doesn't preserve any
caller-saved registers.  _dl_tlsdesc_dynamic saved and restored integer
caller-saved registers, but didn't preserve any other caller-saved
registers.  Add _dl_tlsdesc_dynamic IFUNC functions for FNSAVE, FXSAVE,
XSAVE and XSAVEC to save and restore all caller-saved registers.  This
fixes BZ #31372.

Add GLRO(dl_x86_64_runtime_resolve) with GLRO(dl_x86_tlsdesc_dynamic)
to optimize elf_machine_runtime_setup.
Reviewed-by: Noah Goldstein <goldstein.w.n@gmail.com>
This commit is contained in:
H.J. Lu
2024-02-26 06:37:03 -08:00
parent e6350be7e9
commit 0aac205a81
24 changed files with 914 additions and 207 deletions
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31
elf/tst-gnu2-tls2mod0.c Normal file
View File

@@ -0,0 +1,31 @@
/* DSO used by tst-gnu2-tls2.
Copyright (C) 2024 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
#include "tst-gnu2-tls2.h"
__thread struct tls tls_var0 __attribute__ ((visibility ("hidden")));
struct tls *
apply_tls (struct tls *p)
{
BEFORE_TLSDESC_CALL ();
tls_var0 = *p;
struct tls *ret = &tls_var0;
AFTER_TLSDESC_CALL ();
return ret;
}