1/* Thread-local storage handling in the ELF dynamic linker. 2 AArch64 version. 3 Copyright (C) 2011-2022 Free Software Foundation, Inc. 4 5 This file is part of the GNU C Library. 6 7 The GNU C Library is free software; you can redistribute it and/or 8 modify it under the terms of the GNU Lesser General Public 9 License as published by the Free Software Foundation; either 10 version 2.1 of the License, or (at your option) any later version. 11 12 The GNU C Library is distributed in the hope that it will be useful, 13 but WITHOUT ANY WARRANTY; without even the implied warranty of 14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 15 Lesser General Public License for more details. 16 17 You should have received a copy of the GNU Lesser General Public 18 License along with the GNU C Library; if not, see 19 <https://www.gnu.org/licenses/>. */ 20 21#include <sysdep.h> 22#include <tls.h> 23#include "tlsdesc.h" 24 25#define NSAVEDQREGPAIRS 16 26#define SAVE_Q_REGISTERS \ 27 stp q0, q1, [sp, #-32*NSAVEDQREGPAIRS]!; \ 28 cfi_adjust_cfa_offset (32*NSAVEDQREGPAIRS); \ 29 stp q2, q3, [sp, #32*1]; \ 30 stp q4, q5, [sp, #32*2]; \ 31 stp q6, q7, [sp, #32*3]; \ 32 stp q8, q9, [sp, #32*4]; \ 33 stp q10, q11, [sp, #32*5]; \ 34 stp q12, q13, [sp, #32*6]; \ 35 stp q14, q15, [sp, #32*7]; \ 36 stp q16, q17, [sp, #32*8]; \ 37 stp q18, q19, [sp, #32*9]; \ 38 stp q20, q21, [sp, #32*10]; \ 39 stp q22, q23, [sp, #32*11]; \ 40 stp q24, q25, [sp, #32*12]; \ 41 stp q26, q27, [sp, #32*13]; \ 42 stp q28, q29, [sp, #32*14]; \ 43 stp q30, q31, [sp, #32*15]; 44 45#define RESTORE_Q_REGISTERS \ 46 ldp q2, q3, [sp, #32*1]; \ 47 ldp q4, q5, [sp, #32*2]; \ 48 ldp q6, q7, [sp, #32*3]; \ 49 ldp q8, q9, [sp, #32*4]; \ 50 ldp q10, q11, [sp, #32*5]; \ 51 ldp q12, q13, [sp, #32*6]; \ 52 ldp q14, q15, [sp, #32*7]; \ 53 ldp q16, q17, [sp, #32*8]; \ 54 ldp q18, q19, [sp, #32*9]; \ 55 ldp q20, q21, [sp, #32*10]; \ 56 ldp q22, q23, [sp, #32*11]; \ 57 ldp q24, q25, [sp, #32*12]; \ 58 ldp q26, q27, [sp, #32*13]; \ 59 ldp q28, q29, [sp, #32*14]; \ 60 ldp q30, q31, [sp, #32*15]; \ 61 ldp q0, q1, [sp], #32*NSAVEDQREGPAIRS; \ 62 cfi_adjust_cfa_offset (-32*NSAVEDQREGPAIRS); 63 64 .text 65 66 /* Compute the thread pointer offset for symbols in the static 67 TLS block. The offset is the same for all threads. 68 Prototype: 69 _dl_tlsdesc_return (tlsdesc *) ; 70 */ 71 .hidden _dl_tlsdesc_return 72 .global _dl_tlsdesc_return 73 .type _dl_tlsdesc_return,%function 74 cfi_startproc 75 .align 2 76_dl_tlsdesc_return: 77 BTI_C 78 PTR_ARG (0) 79 ldr PTR_REG (0), [x0, #PTR_SIZE] 80 RET 81 cfi_endproc 82 .size _dl_tlsdesc_return, .-_dl_tlsdesc_return 83 84 /* Handler for undefined weak TLS symbols. 85 Prototype: 86 _dl_tlsdesc_undefweak (tlsdesc *); 87 88 The second word of the descriptor contains the addend. 89 Return the addend minus the thread pointer. This ensures 90 that when the caller adds on the thread pointer it gets back 91 the addend. */ 92 93 .hidden _dl_tlsdesc_undefweak 94 .global _dl_tlsdesc_undefweak 95 .type _dl_tlsdesc_undefweak,%function 96 cfi_startproc 97 .align 2 98_dl_tlsdesc_undefweak: 99 BTI_C 100 str x1, [sp, #-16]! 101 cfi_adjust_cfa_offset (16) 102 PTR_ARG (0) 103 ldr PTR_REG (0), [x0, #PTR_SIZE] 104 mrs x1, tpidr_el0 105 sub PTR_REG (0), PTR_REG (0), PTR_REG (1) 106 ldr x1, [sp], #16 107 cfi_adjust_cfa_offset (-16) 108 RET 109 cfi_endproc 110 .size _dl_tlsdesc_undefweak, .-_dl_tlsdesc_undefweak 111 112#ifdef SHARED 113 /* Handler for dynamic TLS symbols. 114 Prototype: 115 _dl_tlsdesc_dynamic (tlsdesc *) ; 116 117 The second word of the descriptor points to a 118 tlsdesc_dynamic_arg structure. 119 120 Returns the offset between the thread pointer and the 121 object referenced by the argument. 122 123 ptrdiff_t 124 __attribute__ ((__regparm__ (1))) 125 _dl_tlsdesc_dynamic (struct tlsdesc *tdp) 126 { 127 struct tlsdesc_dynamic_arg *td = tdp->arg; 128 dtv_t *dtv = *(dtv_t **)((char *)__thread_pointer + TCBHEAD_DTV); 129 if (__builtin_expect (td->gen_count <= dtv[0].counter 130 && (dtv[td->tlsinfo.ti_module].pointer.val 131 != TLS_DTV_UNALLOCATED), 132 1)) 133 return dtv[td->tlsinfo.ti_module].pointer.val 134 + td->tlsinfo.ti_offset 135 - __thread_pointer; 136 137 return ___tls_get_addr (&td->tlsinfo) - __thread_pointer; 138 } 139 */ 140 141 .hidden _dl_tlsdesc_dynamic 142 .global _dl_tlsdesc_dynamic 143 .type _dl_tlsdesc_dynamic,%function 144 cfi_startproc 145 .align 2 146_dl_tlsdesc_dynamic: 147 BTI_C 148 PTR_ARG (0) 149 150 /* Save just enough registers to support fast path, if we fall 151 into slow path we will save additional registers. */ 152 stp x1, x2, [sp, #-32]! 153 cfi_adjust_cfa_offset (32) 154 stp x3, x4, [sp, #16] 155 cfi_rel_offset (x1, 0) 156 cfi_rel_offset (x2, 8) 157 cfi_rel_offset (x3, 16) 158 cfi_rel_offset (x4, 24) 159 160 mrs x4, tpidr_el0 161 ldr PTR_REG (1), [x0,#TLSDESC_ARG] 162 ldr PTR_REG (0), [x4,#TCBHEAD_DTV] 163 ldr PTR_REG (3), [x1,#TLSDESC_GEN_COUNT] 164 ldr PTR_REG (2), [x0,#DTV_COUNTER] 165 cmp PTR_REG (3), PTR_REG (2) 166 b.hi 2f 167 /* Load r2 = td->tlsinfo.ti_module and r3 = td->tlsinfo.ti_offset. */ 168 ldp PTR_REG (2), PTR_REG (3), [x1,#TLSDESC_MODID] 169 add PTR_REG (0), PTR_REG (0), PTR_REG (2), lsl #(PTR_LOG_SIZE + 1) 170 ldr PTR_REG (0), [x0] /* Load val member of DTV entry. */ 171 cmp PTR_REG (0), #TLS_DTV_UNALLOCATED 172 b.eq 2f 173 cfi_remember_state 174 sub PTR_REG (3), PTR_REG (3), PTR_REG (4) 175 add PTR_REG (0), PTR_REG (0), PTR_REG (3) 1761: 177 ldp x3, x4, [sp, #16] 178 ldp x1, x2, [sp], #32 179 cfi_adjust_cfa_offset (-32) 180 RET 1812: 182 /* This is the slow path. We need to call __tls_get_addr() which 183 means we need to save and restore all the register that the 184 callee will trash. */ 185 186 /* Save the remaining registers that we must treat as caller save. */ 187 cfi_restore_state 188# if HAVE_AARCH64_PAC_RET 189 PACIASP 190 cfi_window_save 191# endif 192# define NSAVEXREGPAIRS 8 193 stp x29, x30, [sp,#-16*NSAVEXREGPAIRS]! 194 cfi_adjust_cfa_offset (16*NSAVEXREGPAIRS) 195 cfi_rel_offset (x29, 0) 196 cfi_rel_offset (x30, 8) 197 mov x29, sp 198 stp x5, x6, [sp, #16*1] 199 stp x7, x8, [sp, #16*2] 200 stp x9, x10, [sp, #16*3] 201 stp x11, x12, [sp, #16*4] 202 stp x13, x14, [sp, #16*5] 203 stp x15, x16, [sp, #16*6] 204 stp x17, x18, [sp, #16*7] 205 cfi_rel_offset (x5, 16*1) 206 cfi_rel_offset (x6, 16*1+8) 207 cfi_rel_offset (x7, 16*2) 208 cfi_rel_offset (x8, 16*2+8) 209 cfi_rel_offset (x9, 16*3) 210 cfi_rel_offset (x10, 16*3+8) 211 cfi_rel_offset (x11, 16*4) 212 cfi_rel_offset (x12, 16*4+8) 213 cfi_rel_offset (x13, 16*5) 214 cfi_rel_offset (x14, 16*5+8) 215 cfi_rel_offset (x15, 16*6) 216 cfi_rel_offset (x16, 16*6+8) 217 cfi_rel_offset (x17, 16*7) 218 cfi_rel_offset (x18, 16*7+8) 219 220 SAVE_Q_REGISTERS 221 222 mov x0, x1 223 bl __tls_get_addr 224 225 mrs x1, tpidr_el0 226 sub PTR_REG (0), PTR_REG (0), PTR_REG (1) 227 228 RESTORE_Q_REGISTERS 229 230 ldp x5, x6, [sp, #16*1] 231 ldp x7, x8, [sp, #16*2] 232 ldp x9, x10, [sp, #16*3] 233 ldp x11, x12, [sp, #16*4] 234 ldp x13, x14, [sp, #16*5] 235 ldp x15, x16, [sp, #16*6] 236 ldp x17, x18, [sp, #16*7] 237 238 ldp x29, x30, [sp], #16*NSAVEXREGPAIRS 239 cfi_adjust_cfa_offset (-16*NSAVEXREGPAIRS) 240 cfi_restore (x29) 241 cfi_restore (x30) 242# if HAVE_AARCH64_PAC_RET 243 AUTIASP 244 cfi_window_save 245# endif 246 b 1b 247 cfi_endproc 248 .size _dl_tlsdesc_dynamic, .-_dl_tlsdesc_dynamic 249# undef NSAVEXREGPAIRS 250#endif 251