mirror of
https://sourceware.org/git/glibc.git
synced 2024-12-14 07:10:05 +00:00
a364304718
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>
(cherry picked from commit 0aac205a81)
119 lines
3.7 KiB
ArmAsm
119 lines
3.7 KiB
ArmAsm
/* Thread-local storage handling in the ELF dynamic linker. i386 version.
|
|
Copyright (C) 2004-2024 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 <sysdep.h>
|
|
#include <tls.h>
|
|
#include <cpu-features-offsets.h>
|
|
#include <features-offsets.h>
|
|
#include "tlsdesc.h"
|
|
|
|
#ifndef DL_STACK_ALIGNMENT
|
|
/* Due to GCC bug:
|
|
|
|
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58066
|
|
|
|
__tls_get_addr may be called with 4-byte stack alignment. Although
|
|
this bug has been fixed in GCC 4.9.4, 5.3 and 6, we can't assume
|
|
that stack will be always aligned at 16 bytes. */
|
|
# define DL_STACK_ALIGNMENT 4
|
|
#endif
|
|
|
|
/* True if _dl_tlsdesc_dynamic should align stack for STATE_SAVE or align
|
|
stack to MINIMUM_ALIGNMENT bytes before calling ___tls_get_addr. */
|
|
#define DL_RUNTIME_RESOLVE_REALIGN_STACK \
|
|
(STATE_SAVE_ALIGNMENT > DL_STACK_ALIGNMENT \
|
|
|| MINIMUM_ALIGNMENT > DL_STACK_ALIGNMENT)
|
|
|
|
.text
|
|
|
|
/* This function is used to compute the TP offset for symbols in
|
|
Static TLS, i.e., whose TP offset is the same for all
|
|
threads.
|
|
|
|
The incoming %eax points to the TLS descriptor, such that
|
|
0(%eax) points to _dl_tlsdesc_return itself, and 4(%eax) holds
|
|
the TP offset of the symbol corresponding to the object
|
|
denoted by the argument. */
|
|
|
|
.hidden _dl_tlsdesc_return
|
|
.global _dl_tlsdesc_return
|
|
.type _dl_tlsdesc_return,@function
|
|
cfi_startproc
|
|
.align 16
|
|
_dl_tlsdesc_return:
|
|
movl 4(%eax), %eax
|
|
ret
|
|
cfi_endproc
|
|
.size _dl_tlsdesc_return, .-_dl_tlsdesc_return
|
|
|
|
/* This function is used for undefined weak TLS symbols, for
|
|
which the base address (i.e., disregarding any addend) should
|
|
resolve to NULL.
|
|
|
|
%eax points to the TLS descriptor, such that 0(%eax) points to
|
|
_dl_tlsdesc_undefweak itself, and 4(%eax) holds the addend.
|
|
We return the addend minus the TP, such that, when the caller
|
|
adds TP, it gets the addend back. If that's zero, as usual,
|
|
that's most likely a NULL pointer. */
|
|
|
|
.hidden _dl_tlsdesc_undefweak
|
|
.global _dl_tlsdesc_undefweak
|
|
.type _dl_tlsdesc_undefweak,@function
|
|
cfi_startproc
|
|
.align 16
|
|
_dl_tlsdesc_undefweak:
|
|
movl 4(%eax), %eax
|
|
subl %gs:0, %eax
|
|
ret
|
|
cfi_endproc
|
|
.size _dl_tlsdesc_undefweak, .-_dl_tlsdesc_undefweak
|
|
|
|
#ifdef SHARED
|
|
# define USE_FNSAVE
|
|
# define MINIMUM_ALIGNMENT 4
|
|
# define STATE_SAVE_ALIGNMENT 4
|
|
# define _dl_tlsdesc_dynamic _dl_tlsdesc_dynamic_fnsave
|
|
# include "dl-tlsdesc-dynamic.h"
|
|
# undef _dl_tlsdesc_dynamic
|
|
# undef MINIMUM_ALIGNMENT
|
|
# undef USE_FNSAVE
|
|
|
|
# define MINIMUM_ALIGNMENT 16
|
|
|
|
# define USE_FXSAVE
|
|
# define STATE_SAVE_ALIGNMENT 16
|
|
# define _dl_tlsdesc_dynamic _dl_tlsdesc_dynamic_fxsave
|
|
# include "dl-tlsdesc-dynamic.h"
|
|
# undef _dl_tlsdesc_dynamic
|
|
# undef USE_FXSAVE
|
|
|
|
# define USE_XSAVE
|
|
# define STATE_SAVE_ALIGNMENT 64
|
|
# define _dl_tlsdesc_dynamic _dl_tlsdesc_dynamic_xsave
|
|
# include "dl-tlsdesc-dynamic.h"
|
|
# undef _dl_tlsdesc_dynamic
|
|
# undef USE_XSAVE
|
|
|
|
# define USE_XSAVEC
|
|
# define STATE_SAVE_ALIGNMENT 64
|
|
# define _dl_tlsdesc_dynamic _dl_tlsdesc_dynamic_xsavec
|
|
# include "dl-tlsdesc-dynamic.h"
|
|
# undef _dl_tlsdesc_dynamic
|
|
# undef USE_XSAVEC
|
|
#endif /* SHARED */
|