diff options
Diffstat (limited to 'sysdeps/x86_64/dl-tlsdesc-dynamic.h')
| -rw-r--r-- | sysdeps/x86_64/dl-tlsdesc-dynamic.h | 166 |
1 files changed, 166 insertions, 0 deletions
diff --git a/sysdeps/x86_64/dl-tlsdesc-dynamic.h b/sysdeps/x86_64/dl-tlsdesc-dynamic.h new file mode 100644 index 0000000000..0c2e8d5320 --- /dev/null +++ b/sysdeps/x86_64/dl-tlsdesc-dynamic.h @@ -0,0 +1,166 @@ +/* Thread-local storage handling in the ELF dynamic linker. x86_64 version. + Copyright (C) 2004-2024 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/>. */ + +#ifndef SECTION +# define SECTION(p) p +#endif + +#undef REGISTER_SAVE_AREA +#undef LOCAL_STORAGE_AREA +#undef BASE + +#include "dl-trampoline-state.h" + + .section SECTION(.text),"ax",@progbits + + .hidden _dl_tlsdesc_dynamic + .global _dl_tlsdesc_dynamic + .type _dl_tlsdesc_dynamic,@function + + /* %rax points to the TLS descriptor, such that 0(%rax) points to + _dl_tlsdesc_dynamic itself, and 8(%rax) points to a struct + tlsdesc_dynamic_arg object. It must return in %rax the offset + between the thread pointer and the object denoted by the + argument, without clobbering any registers. + + The assembly code that follows is a rendition of the following + C code, hand-optimized a little bit. + +ptrdiff_t +_dl_tlsdesc_dynamic (register struct tlsdesc *tdp asm ("%rax")) +{ + struct tlsdesc_dynamic_arg *td = tdp->arg; + dtv_t *dtv = *(dtv_t **)((char *)__thread_pointer + DTV_OFFSET); + if (__builtin_expect (td->gen_count <= dtv[0].counter + && (dtv[td->tlsinfo.ti_module].pointer.val + != TLS_DTV_UNALLOCATED), + 1)) + return dtv[td->tlsinfo.ti_module].pointer.val + td->tlsinfo.ti_offset + - __thread_pointer; + + return __tls_get_addr_internal (&td->tlsinfo) - __thread_pointer; +} +*/ + cfi_startproc + .align 16 +_dl_tlsdesc_dynamic: + _CET_ENDBR + /* Preserve call-clobbered registers that we modify. + We need two scratch regs anyway. */ + movq %rsi, -16(%rsp) + mov %fs:DTV_OFFSET, %RSI_LP + movq %rdi, -8(%rsp) + movq TLSDESC_ARG(%rax), %rdi + movq (%rsi), %rax + cmpq %rax, TLSDESC_GEN_COUNT(%rdi) + ja 2f + movq TLSDESC_MODID(%rdi), %rax + salq $4, %rax + movq (%rax,%rsi), %rax + cmpq $-1, %rax + je 2f + addq TLSDESC_MODOFF(%rdi), %rax +1: + movq -16(%rsp), %rsi + sub %fs:0, %RAX_LP + movq -8(%rsp), %rdi + ret +2: +#if DL_RUNTIME_RESOLVE_REALIGN_STACK + movq %rbx, -24(%rsp) + mov %RSP_LP, %RBX_LP + cfi_def_cfa_register(%rbx) + and $-STATE_SAVE_ALIGNMENT, %RSP_LP +#endif +#ifdef REGISTER_SAVE_AREA +# if DL_RUNTIME_RESOLVE_REALIGN_STACK + /* STATE_SAVE_OFFSET has space for 8 integer registers. But we + need space for RCX, RDX, RSI, RDI, R8, R9, R10 and R11, plus + RBX above. */ + sub $(REGISTER_SAVE_AREA + STATE_SAVE_ALIGNMENT), %RSP_LP +# else + sub $REGISTER_SAVE_AREA, %RSP_LP + cfi_adjust_cfa_offset(REGISTER_SAVE_AREA) +# endif +#else + /* Allocate stack space of the required size to save the state. */ + sub _rtld_local_ro+RTLD_GLOBAL_RO_DL_X86_CPU_FEATURES_OFFSET+XSAVE_STATE_SIZE_OFFSET(%rip), %RSP_LP +#endif + /* Besides rdi and rsi, saved above, save rcx, rdx, r8, r9, + r10 and r11. */ + movq %rcx, REGISTER_SAVE_RCX(%rsp) + movq %rdx, REGISTER_SAVE_RDX(%rsp) + movq %r8, REGISTER_SAVE_R8(%rsp) + movq %r9, REGISTER_SAVE_R9(%rsp) + movq %r10, REGISTER_SAVE_R10(%rsp) + movq %r11, REGISTER_SAVE_R11(%rsp) +#ifdef USE_FXSAVE + fxsave STATE_SAVE_OFFSET(%rsp) +#else + movl $TLSDESC_CALL_STATE_SAVE_MASK, %eax + xorl %edx, %edx + /* Clear the XSAVE Header. */ +# ifdef USE_XSAVE + movq %rdx, (STATE_SAVE_OFFSET + 512)(%rsp) + movq %rdx, (STATE_SAVE_OFFSET + 512 + 8)(%rsp) +# endif + movq %rdx, (STATE_SAVE_OFFSET + 512 + 8 * 2)(%rsp) + movq %rdx, (STATE_SAVE_OFFSET + 512 + 8 * 3)(%rsp) + movq %rdx, (STATE_SAVE_OFFSET + 512 + 8 * 4)(%rsp) + movq %rdx, (STATE_SAVE_OFFSET + 512 + 8 * 5)(%rsp) + movq %rdx, (STATE_SAVE_OFFSET + 512 + 8 * 6)(%rsp) + movq %rdx, (STATE_SAVE_OFFSET + 512 + 8 * 7)(%rsp) +# ifdef USE_XSAVE + xsave STATE_SAVE_OFFSET(%rsp) +# else + xsavec STATE_SAVE_OFFSET(%rsp) +# endif +#endif + /* %rdi already points to the tlsinfo data structure. */ + call HIDDEN_JUMPTARGET (__tls_get_addr) + # Get register content back. +#ifdef USE_FXSAVE + fxrstor STATE_SAVE_OFFSET(%rsp) +#else + /* Save and retore __tls_get_addr return value stored in RAX. */ + mov %RAX_LP, %RCX_LP + movl $TLSDESC_CALL_STATE_SAVE_MASK, %eax + xorl %edx, %edx + xrstor STATE_SAVE_OFFSET(%rsp) + mov %RCX_LP, %RAX_LP +#endif + movq REGISTER_SAVE_R11(%rsp), %r11 + movq REGISTER_SAVE_R10(%rsp), %r10 + movq REGISTER_SAVE_R9(%rsp), %r9 + movq REGISTER_SAVE_R8(%rsp), %r8 + movq REGISTER_SAVE_RDX(%rsp), %rdx + movq REGISTER_SAVE_RCX(%rsp), %rcx +#if DL_RUNTIME_RESOLVE_REALIGN_STACK + mov %RBX_LP, %RSP_LP + cfi_def_cfa_register(%rsp) + movq -24(%rsp), %rbx + cfi_restore(%rbx) +#else + add $REGISTER_SAVE_AREA, %RSP_LP + cfi_adjust_cfa_offset(-REGISTER_SAVE_AREA) +#endif + jmp 1b + cfi_endproc + .size _dl_tlsdesc_dynamic, .-_dl_tlsdesc_dynamic + +#undef STATE_SAVE_ALIGNMENT |