diff options
Diffstat (limited to 'sysdeps/i386/dl-tlsdesc-dynamic.h')
| -rw-r--r-- | sysdeps/i386/dl-tlsdesc-dynamic.h | 190 |
1 files changed, 190 insertions, 0 deletions
diff --git a/sysdeps/i386/dl-tlsdesc-dynamic.h b/sysdeps/i386/dl-tlsdesc-dynamic.h new file mode 100644 index 0000000000..3627028577 --- /dev/null +++ b/sysdeps/i386/dl-tlsdesc-dynamic.h @@ -0,0 +1,190 @@ +/* Thread-local storage handling in the ELF dynamic linker. i386 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/>. */ + +#undef REGISTER_SAVE_AREA + +#if !defined USE_FNSAVE && (STATE_SAVE_ALIGNMENT % 16) != 0 +# error STATE_SAVE_ALIGNMENT must be multiple of 16 +#endif + +#if DL_RUNTIME_RESOLVE_REALIGN_STACK +# ifdef USE_FNSAVE +# error USE_FNSAVE shouldn't be defined +# endif +# ifdef USE_FXSAVE +/* Use fxsave to save all registers. */ +# define REGISTER_SAVE_AREA 512 +# endif +#else +# ifdef USE_FNSAVE +/* Use fnsave to save x87 FPU stack registers. */ +# define REGISTER_SAVE_AREA 108 +# else +# ifndef USE_FXSAVE +# error USE_FXSAVE must be defined +# endif +/* Use fxsave to save all registers. Add 12 bytes to align the stack + to 16 bytes. */ +# define REGISTER_SAVE_AREA (512 + 12) +# endif +#endif + + .hidden _dl_tlsdesc_dynamic + .global _dl_tlsdesc_dynamic + .type _dl_tlsdesc_dynamic,@function + + /* This function is used for symbols that need dynamic TLS. + + %eax points to the TLS descriptor, such that 0(%eax) points to + _dl_tlsdesc_dynamic itself, and 4(%eax) points to a struct + tlsdesc_dynamic_arg object. It must return in %eax 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 +__attribute__ ((__regparm__ (1))) +_dl_tlsdesc_dynamic (struct tlsdesc *tdp) +{ + 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 (&td->tlsinfo) - __thread_pointer; +} +*/ + cfi_startproc + .align 16 +_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) + movl %ecx, 20(%esp) + movl %edx, 24(%esp) + movl TLSDESC_ARG(%eax), %eax + movl %gs:DTV_OFFSET, %edx + movl TLSDESC_GEN_COUNT(%eax), %ecx + cmpl (%edx), %ecx + ja 2f + movl TLSDESC_MODID(%eax), %ecx + movl (%edx,%ecx,8), %edx + cmpl $-1, %edx + je 2f + movl TLSDESC_MODOFF(%eax), %eax + addl %edx, %eax +1: + movl 20(%esp), %ecx + subl %gs:0, %eax + movl 24(%esp), %edx + addl $32, %esp + cfi_adjust_cfa_offset (-32) + ret + .p2align 4,,7 +2: + cfi_adjust_cfa_offset (32) +#if DL_RUNTIME_RESOLVE_REALIGN_STACK + movl %ebx, -28(%esp) + movl %esp, %ebx + cfi_def_cfa_register(%ebx) + and $-STATE_SAVE_ALIGNMENT, %esp +#endif +#ifdef REGISTER_SAVE_AREA + subl $REGISTER_SAVE_AREA, %esp +# if !DL_RUNTIME_RESOLVE_REALIGN_STACK + cfi_adjust_cfa_offset(REGISTER_SAVE_AREA) +# endif +#else +# if !DL_RUNTIME_RESOLVE_REALIGN_STACK +# error DL_RUNTIME_RESOLVE_REALIGN_STACK must be true +# endif + /* Allocate stack space of the required size to save the state. */ + LOAD_PIC_REG (cx) + subl RTLD_GLOBAL_RO_DL_X86_CPU_FEATURES_OFFSET+XSAVE_STATE_SIZE_OFFSET+_rtld_local_ro@GOTOFF(%ecx), %esp +#endif +#ifdef USE_FNSAVE + fnsave (%esp) +#elif defined USE_FXSAVE + fxsave (%esp) +#else + /* Save the argument for ___tls_get_addr in EAX. */ + movl %eax, %ecx + movl $TLSDESC_CALL_STATE_SAVE_MASK, %eax + xorl %edx, %edx + /* Clear the XSAVE Header. */ +# ifdef USE_XSAVE + movl %edx, (512)(%esp) + movl %edx, (512 + 4 * 1)(%esp) + movl %edx, (512 + 4 * 2)(%esp) + movl %edx, (512 + 4 * 3)(%esp) +# endif + movl %edx, (512 + 4 * 4)(%esp) + movl %edx, (512 + 4 * 5)(%esp) + movl %edx, (512 + 4 * 6)(%esp) + movl %edx, (512 + 4 * 7)(%esp) + movl %edx, (512 + 4 * 8)(%esp) + movl %edx, (512 + 4 * 9)(%esp) + movl %edx, (512 + 4 * 10)(%esp) + movl %edx, (512 + 4 * 11)(%esp) + movl %edx, (512 + 4 * 12)(%esp) + movl %edx, (512 + 4 * 13)(%esp) + movl %edx, (512 + 4 * 14)(%esp) + movl %edx, (512 + 4 * 15)(%esp) +# ifdef USE_XSAVE + xsave (%esp) +# else + xsavec (%esp) +# endif + /* Restore the argument for ___tls_get_addr in EAX. */ + movl %ecx, %eax +#endif + call HIDDEN_JUMPTARGET (___tls_get_addr) + /* Get register content back. */ +#ifdef USE_FNSAVE + frstor (%esp) +#elif defined USE_FXSAVE + fxrstor (%esp) +#else + /* Save and retore ___tls_get_addr return value stored in EAX. */ + movl %eax, %ecx + movl $TLSDESC_CALL_STATE_SAVE_MASK, %eax + xorl %edx, %edx + xrstor (%esp) + movl %ecx, %eax +#endif +#if DL_RUNTIME_RESOLVE_REALIGN_STACK + mov %ebx, %esp + cfi_def_cfa_register(%esp) + movl -28(%esp), %ebx + cfi_restore(%ebx) +#else + addl $REGISTER_SAVE_AREA, %esp + cfi_adjust_cfa_offset(-REGISTER_SAVE_AREA) +#endif + jmp 1b + cfi_endproc + .size _dl_tlsdesc_dynamic, .-_dl_tlsdesc_dynamic + +#undef STATE_SAVE_ALIGNMENT |