glibc/sysdeps/x86_64/dl-trampoline-state.h
H.J. Lu 0aac205a81 x86: Update _dl_tlsdesc_dynamic to preserve caller-saved registers
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>
2024-02-28 09:02:56 -08:00

52 lines
1.8 KiB
C

/* x86-64 PLT dl-trampoline state 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/>. */
#if (STATE_SAVE_ALIGNMENT % 16) != 0
# error STATE_SAVE_ALIGNMENT must be multiple of 16
#endif
#if (STATE_SAVE_OFFSET % STATE_SAVE_ALIGNMENT) != 0
# error STATE_SAVE_OFFSET must be multiple of STATE_SAVE_ALIGNMENT
#endif
#if DL_RUNTIME_RESOLVE_REALIGN_STACK
/* Local stack area before jumping to function address: RBX. */
# define LOCAL_STORAGE_AREA 8
# define BASE rbx
# ifdef USE_FXSAVE
/* Use fxsave to save XMM registers. */
# define REGISTER_SAVE_AREA (512 + STATE_SAVE_OFFSET)
# if (REGISTER_SAVE_AREA % 16) != 0
# error REGISTER_SAVE_AREA must be multiple of 16
# endif
# endif
#else
# ifndef USE_FXSAVE
# error USE_FXSAVE must be defined
# endif
/* Use fxsave to save XMM registers. */
# define REGISTER_SAVE_AREA (512 + STATE_SAVE_OFFSET + 8)
/* Local stack area before jumping to function address: All saved
registers. */
# define LOCAL_STORAGE_AREA REGISTER_SAVE_AREA
# define BASE rsp
# if (REGISTER_SAVE_AREA % 16) != 8
# error REGISTER_SAVE_AREA must be odd multiple of 8
# endif
#endif