mirror of
https://sourceware.org/git/glibc.git
synced 2025-08-08 17:42:12 +03:00
848f0e46f0
Compiler generates the following instruction sequence for dynamic TLS access: leal tls_var@tlsgd(,%ebx,1), %eax call ___tls_get_addr@PLT CALL instruction is transparent to compiler which assumes all registers, except for EFLAGS, AX, CX, and DX, are unchanged after CALL. But ___tls_get_addr is a normal function which doesn't preserve any vector registers. 1. Rename the generic __tls_get_addr function to ___tls_get_addr_internal. 2. Change ___tls_get_addr to a wrapper function with implementations for FNSAVE, FXSAVE, XSAVE and XSAVEC to save and restore all vector registers. 3. dl-tlsdesc-dynamic.h has: _dl_tlsdesc_dynamic: /* Like all TLS resolvers, preserve call-clobbered registers. We need two scratch regs anyway. */ subl $32, %esp cfi_adjust_cfa_offset (32) It is wrong to use movl %ebx, -28(%esp) movl %esp, %ebx cfi_def_cfa_register(%ebx) ... mov %ebx, %esp cfi_def_cfa_register(%esp) movl -28(%esp), %ebx to preserve EBX on stack. Fix it with: movl %ebx, 28(%esp) movl %esp, %ebx cfi_def_cfa_register(%ebx) ... mov %ebx, %esp cfi_def_cfa_register(%esp) movl 28(%esp), %ebx 4. Update _dl_tlsdesc_dynamic to call ___tls_get_addr_internal directly. 5. Add have-test-mtls-traditional to compile tst-tls23-mod.c with traditional TLS variant to verify the fix. 6. Define DL_RUNTIME_RESOLVE_REALIGN_STACK in sysdeps/x86/sysdep.h. This fixes BZ #32996. Co-Authored-By: Adhemerval Zanella <adhemerval.zanella@linaro.org> Signed-off-by: H.J. Lu <hjl.tools@gmail.com> Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
105 lines
3.3 KiB
ArmAsm
105 lines
3.3 KiB
ArmAsm
/* Thread-local storage handling in the ELF dynamic linker. x86_64 version.
|
|
Copyright (C) 2004-2025 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 <isa-level.h>
|
|
#include "tlsdesc.h"
|
|
|
|
/* Area on stack to save and restore registers used for parameter
|
|
passing when calling _dl_tlsdesc_dynamic. */
|
|
#define REGISTER_SAVE_RCX 0
|
|
#define REGISTER_SAVE_RDX (REGISTER_SAVE_RCX + 8)
|
|
#define REGISTER_SAVE_R8 (REGISTER_SAVE_RDX + 8)
|
|
#define REGISTER_SAVE_R9 (REGISTER_SAVE_R8 + 8)
|
|
#define REGISTER_SAVE_R10 (REGISTER_SAVE_R9 + 8)
|
|
#define REGISTER_SAVE_R11 (REGISTER_SAVE_R10 + 8)
|
|
|
|
.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 %rax points to the TLS descriptor, such that
|
|
0(%rax) points to _dl_tlsdesc_return itself, and 8(%rax) 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:
|
|
_CET_ENDBR
|
|
movq 8(%rax), %rax
|
|
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.
|
|
|
|
%rax points to the TLS descriptor, such that 0(%rax) points to
|
|
_dl_tlsdesc_undefweak itself, and 8(%rax) 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:
|
|
_CET_ENDBR
|
|
movq 8(%rax), %rax
|
|
sub %fs:0, %RAX_LP
|
|
ret
|
|
cfi_endproc
|
|
.size _dl_tlsdesc_undefweak, .-_dl_tlsdesc_undefweak
|
|
|
|
#ifdef SHARED
|
|
# if MINIMUM_X86_ISA_LEVEL < AVX_X86_ISA_LEVEL
|
|
# 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
|
|
# endif
|
|
|
|
# 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 */
|