glibc/elf/tst-tls23-mod.c

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i386: Update ___tls_get_addr to preserve vector registers 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>
2025-06-08 21:22:10 +00:00
/* DSO used by tst-tls23.
Copyright (C) 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/>. */
i386: Update ___tls_get_addr to preserve vector registers 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>
2025-06-08 21:22:10 +00:00
#include <tst-tls23.h>
i386: Update ___tls_get_addr to preserve vector registers 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>
2025-06-08 21:22:10 +00:00
__thread struct tls tls_var0 __attribute__ ((visibility ("hidden")));
i386: Update ___tls_get_addr to preserve vector registers 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>
2025-06-08 21:22:10 +00:00
struct tls *
apply_tls (struct tls *p)
{
INIT_TLS_CALL ();
BEFORE_TLS_CALL ();
tls_var0 = *p;
struct tls *ret = &tls_var0;
AFTER_TLS_CALL ();
return ret;
}