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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>
102 lines
3.1 KiB
ArmAsm
102 lines
3.1 KiB
ArmAsm
/* Thread-local storage handling in the ELF dynamic linker. i386 version.
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Copyright (C) 2004-2025 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<https://www.gnu.org/licenses/>. */
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#include <sysdep.h>
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#include <tls.h>
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#include <cpu-features-offsets.h>
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#include <features-offsets.h>
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#include "tlsdesc.h"
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.text
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/* This function is used to compute the TP offset for symbols in
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Static TLS, i.e., whose TP offset is the same for all
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threads.
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The incoming %eax points to the TLS descriptor, such that
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0(%eax) points to _dl_tlsdesc_return itself, and 4(%eax) holds
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the TP offset of the symbol corresponding to the object
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denoted by the argument. */
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.hidden _dl_tlsdesc_return
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.global _dl_tlsdesc_return
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.type _dl_tlsdesc_return,@function
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cfi_startproc
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.align 16
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_dl_tlsdesc_return:
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movl 4(%eax), %eax
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ret
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cfi_endproc
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.size _dl_tlsdesc_return, .-_dl_tlsdesc_return
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/* This function is used for undefined weak TLS symbols, for
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which the base address (i.e., disregarding any addend) should
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resolve to NULL.
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%eax points to the TLS descriptor, such that 0(%eax) points to
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_dl_tlsdesc_undefweak itself, and 4(%eax) holds the addend.
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We return the addend minus the TP, such that, when the caller
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adds TP, it gets the addend back. If that's zero, as usual,
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that's most likely a NULL pointer. */
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.hidden _dl_tlsdesc_undefweak
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.global _dl_tlsdesc_undefweak
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.type _dl_tlsdesc_undefweak,@function
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cfi_startproc
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.align 16
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_dl_tlsdesc_undefweak:
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movl 4(%eax), %eax
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subl %gs:0, %eax
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ret
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cfi_endproc
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.size _dl_tlsdesc_undefweak, .-_dl_tlsdesc_undefweak
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#ifdef SHARED
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# define USE_FNSAVE
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# define MINIMUM_ALIGNMENT 4
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# define STATE_SAVE_ALIGNMENT 4
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# define _dl_tlsdesc_dynamic _dl_tlsdesc_dynamic_fnsave
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# include "dl-tlsdesc-dynamic.h"
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# undef _dl_tlsdesc_dynamic
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# undef MINIMUM_ALIGNMENT
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# undef USE_FNSAVE
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# define MINIMUM_ALIGNMENT 16
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# define USE_FXSAVE
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# define STATE_SAVE_ALIGNMENT 16
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# define _dl_tlsdesc_dynamic _dl_tlsdesc_dynamic_fxsave
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# include "dl-tlsdesc-dynamic.h"
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# undef _dl_tlsdesc_dynamic
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# undef USE_FXSAVE
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# define USE_XSAVE
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# define STATE_SAVE_ALIGNMENT 64
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# define _dl_tlsdesc_dynamic _dl_tlsdesc_dynamic_xsave
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# include "dl-tlsdesc-dynamic.h"
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# undef _dl_tlsdesc_dynamic
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# undef USE_XSAVE
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# define USE_XSAVEC
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# define STATE_SAVE_ALIGNMENT 64
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# define _dl_tlsdesc_dynamic _dl_tlsdesc_dynamic_xsavec
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# include "dl-tlsdesc-dynamic.h"
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# undef _dl_tlsdesc_dynamic
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# undef USE_XSAVEC
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#endif /* SHARED */
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