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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>
212 lines
7.3 KiB
C
212 lines
7.3 KiB
C
/* Assembler macros for x86.
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Copyright (C) 2017-2025 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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#ifndef _X86_SYSDEP_H
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#define _X86_SYSDEP_H 1
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#include <sysdeps/generic/sysdep.h>
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/* The extended state feature IDs in the state component bitmap. */
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#define X86_XSTATE_X87_ID 0
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#define X86_XSTATE_SSE_ID 1
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#define X86_XSTATE_AVX_ID 2
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#define X86_XSTATE_BNDREGS_ID 3
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#define X86_XSTATE_BNDCFG_ID 4
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#define X86_XSTATE_K_ID 5
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#define X86_XSTATE_ZMM_H_ID 6
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#define X86_XSTATE_ZMM_ID 7
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#define X86_XSTATE_PKRU_ID 9
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#define X86_XSTATE_TILECFG_ID 17
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#define X86_XSTATE_TILEDATA_ID 18
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#define X86_XSTATE_APX_F_ID 19
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#ifdef __x86_64__
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/* Offset for fxsave/xsave area used by _dl_runtime_resolve. Also need
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space to preserve RCX, RDX, RSI, RDI, R8, R9 and RAX. It must be
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aligned to 16 bytes for fxsave and 64 bytes for xsave. It is non-zero
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because MOV, instead of PUSH, is used to save registers onto stack.
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+==================+<- stack frame start aligned at 8 or 16 bytes
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| |<- paddings for stack realignment of 64 bytes
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|------------------|<- xsave buffer end aligned at 64 bytes
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| |<-
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| |<-
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| |<-
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|------------------|<- xsave buffer start at STATE_SAVE_OFFSET(%rsp)
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| |<- 8-byte padding for 64-byte alignment
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| |<- R9
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| |<- R8
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| |<- RDI
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| |<- RSI
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| |<- RDX
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| |<- RCX
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| |<- RAX
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+==================+<- RSP aligned at 64 bytes
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*/
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# define STATE_SAVE_OFFSET (8 * 7 + 8)
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/* _dl_tlsdesc_dynamic preserves RDI, RSI and RBX before realigning
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stack. After realigning stack, it saves RCX, RDX, R8, R9, R10 and
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R11. Allocate space for RDI, RSI and RBX to avoid clobbering saved
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RDI, RSI and RBX values on stack by xsave.
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+==================+<- stack frame start aligned at 8 or 16 bytes
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| |<- RDI saved in the red zone
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| |<- RSI saved in the red zone
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| |<- RBX saved in the red zone
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| |<- paddings for stack realignment of 64 bytes
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|------------------|<- xsave buffer end aligned at 64 bytes
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| |<-
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| |<-
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| |<-
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|------------------|<- xsave buffer start at STATE_SAVE_OFFSET(%rsp)
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| |<- 8-byte padding for 64-byte alignment
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| |<- 8-byte padding for 64-byte alignment
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| |<- R11
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| |<- R10
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| |<- R9
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| |<- R8
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| |<- RDX
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| |<- RCX
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+==================+<- RSP aligned at 64 bytes
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Define the total register save area size for all integer registers by
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adding 24 to STATE_SAVE_OFFSET since RDI, RSI and RBX are saved onto
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stack without adjusting stack pointer first, using the red-zone. */
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# define TLSDESC_CALL_REGISTER_SAVE_AREA (STATE_SAVE_OFFSET + 24)
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/* Save SSE, AVX, AVX512, mask, bound and APX registers. Bound and APX
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registers are mutually exclusive. */
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# define STATE_SAVE_MASK \
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((1 << X86_XSTATE_SSE_ID) \
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| (1 << X86_XSTATE_AVX_ID) \
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| (1 << X86_XSTATE_BNDREGS_ID) \
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| (1 << X86_XSTATE_K_ID) \
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| (1 << X86_XSTATE_ZMM_H_ID) \
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| (1 << X86_XSTATE_ZMM_ID) \
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| (1 << X86_XSTATE_APX_F_ID))
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/* The maximum supported xstate ID. */
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# define X86_XSTATE_MAX_ID X86_XSTATE_APX_F_ID
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/* AMX state mask. */
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# define AMX_STATE_SAVE_MASK \
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((1 << X86_XSTATE_TILECFG_ID) | (1 << X86_XSTATE_TILEDATA_ID))
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/* States to be included in xsave_state_full_size. */
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# define FULL_STATE_SAVE_MASK \
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(STATE_SAVE_MASK | AMX_STATE_SAVE_MASK)
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#else
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/* Offset for fxsave/xsave area used by _dl_tlsdesc_dynamic. Since i386
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uses PUSH to save registers onto stack, use 0 here. */
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# define STATE_SAVE_OFFSET 0
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# define TLSDESC_CALL_REGISTER_SAVE_AREA 0
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/* Save SSE, AVX, AXV512, mask and bound registers. */
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# define STATE_SAVE_MASK \
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((1 << X86_XSTATE_SSE_ID) \
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| (1 << X86_XSTATE_AVX_ID) \
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| (1 << X86_XSTATE_BNDREGS_ID) \
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| (1 << X86_XSTATE_K_ID) \
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| (1 << X86_XSTATE_ZMM_H_ID))
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/* The maximum supported xstate ID. */
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# define X86_XSTATE_MAX_ID X86_XSTATE_ZMM_H_ID
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/* States to be included in xsave_state_size. */
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# define FULL_STATE_SAVE_MASK STATE_SAVE_MASK
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#endif
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/* States which should be saved for TLSDESC_CALL and TLS_DESC_CALL.
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Compiler assumes that all registers, including AMX and x87 FPU
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stack registers, are unchanged after CALL, except for EFLAGS and
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RAX/EAX. */
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#define TLSDESC_CALL_STATE_SAVE_MASK \
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(FULL_STATE_SAVE_MASK | (1 << X86_XSTATE_X87_ID))
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/* Constants for bits in __x86_string_control: */
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/* Avoid short distance REP MOVSB. */
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#define X86_STRING_CONTROL_AVOID_SHORT_DISTANCE_REP_MOVSB (1 << 0)
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#ifdef __ASSEMBLER__
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/* Syntactic details of assembler. */
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/* ELF uses byte-counts for .align, most others use log2 of count of bytes. */
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#define ALIGNARG(log2) 1<<log2
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#define ASM_SIZE_DIRECTIVE(name) .size name,.-name;
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/* Common entry 16 byte aligns. */
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#define ENTRY(name) ENTRY_P2ALIGN (name, 4)
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#undef END
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#define END(name) \
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cfi_endproc; \
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ASM_SIZE_DIRECTIVE(name)
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#define ENTRY_CHK(name) ENTRY (name)
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#define END_CHK(name) END (name)
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/* Since C identifiers are not normally prefixed with an underscore
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on this system, the asm identifier `syscall_error' intrudes on the
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C name space. Make sure we use an innocuous name. */
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#define syscall_error __syscall_error
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#define mcount _mcount
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#undef PSEUDO_END
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#define PSEUDO_END(name) \
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END (name)
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/* Local label name for asm code. */
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#ifndef L
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/* ELF-like local names start with `.L'. */
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# define LOCAL_LABEL(name) .L##name
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# define L(name) LOCAL_LABEL(name)
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#endif
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#define atom_text_section .section ".text.atom", "ax"
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#ifndef DL_STACK_ALIGNMENT
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/* Due to GCC bug:
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58066
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__tls_get_addr may be called with 8-byte/4-byte stack alignment.
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Although this bug has been fixed in GCC 4.9.4, 5.3 and 6, we can't
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assume that stack will be always aligned at 16 bytes. */
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# ifdef __x86_64__
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# define DL_STACK_ALIGNMENT 8
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# define MINIMUM_ALIGNMENT 16
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# else
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# define DL_STACK_ALIGNMENT 4
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# endif
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#endif
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/* True if _dl_runtime_resolve/_dl_tlsdesc_dynamic should align stack for
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STATE_SAVE or align stack to MINIMUM_ALIGNMENT bytes before calling
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_dl_fixup/__tls_get_addr. */
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#define DL_RUNTIME_RESOLVE_REALIGN_STACK \
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(STATE_SAVE_ALIGNMENT > DL_STACK_ALIGNMENT \
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|| MINIMUM_ALIGNMENT > DL_STACK_ALIGNMENT)
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#endif /* __ASSEMBLER__ */
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#endif /* _X86_SYSDEP_H */
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