mirror of
https://sourceware.org/git/glibc.git
synced 2024-11-14 09:01:07 +00:00
0aac205a81
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>
35 lines
1.4 KiB
C
35 lines
1.4 KiB
C
/* x86-64 PLT trampoline register save macros.
|
|
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/>. */
|
|
|
|
#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 8-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 8
|
|
#endif
|
|
|
|
/* True if _dl_runtime_resolve should align stack for STATE_SAVE or align
|
|
stack to 16 bytes before calling _dl_fixup. */
|
|
#define DL_RUNTIME_RESOLVE_REALIGN_STACK \
|
|
(STATE_SAVE_ALIGNMENT > DL_STACK_ALIGNMENT \
|
|
|| 16 > DL_STACK_ALIGNMENT)
|