1 /* Thread-local storage handling in the ELF dynamic linker. s390 version. 2 Copyright (C) 2003-2021 Free Software Foundation, Inc. 3 This file is part of the GNU C Library. 4 5 The GNU C Library is free software; you can redistribute it and/or 6 modify it under the terms of the GNU Lesser General Public 7 License as published by the Free Software Foundation; either 8 version 2.1 of the License, or (at your option) any later version. 9 10 The GNU C Library is distributed in the hope that it will be useful, 11 but WITHOUT ANY WARRANTY; without even the implied warranty of 12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 13 Lesser General Public License for more details. 14 15 You should have received a copy of the GNU Lesser General Public 16 License along with the GNU C Library; if not, see 17 <https://www.gnu.org/licenses/>. */ 18 19 20 /* Type used for the representation of TLS information in the GOT. */ 21 typedef struct 22 { 23 unsigned long int ti_module; 24 unsigned long int ti_offset; 25 } tls_index; 26 27 28 #ifdef SHARED 29 30 extern unsigned long __tls_get_offset (unsigned long got_offset); 31 32 # if IS_IN (rtld) 33 34 # include <shlib-compat.h> 35 36 /* dl-tls.c declares __tls_get_addr as an exported symbol if it is not defined 37 as a macro. It seems suitable to do that in the generic code because all 38 architectures other than s390 export __tls_get_addr. The declaration causes 39 problems in s390 though, so we define __tls_get_addr here to avoid declaring 40 __tls_get_addr again. */ 41 # define __tls_get_addr __tls_get_addr 42 43 extern void *__tls_get_addr (tls_index *ti) attribute_hidden; 44 /* Make a temporary alias of __tls_get_addr to remove the hidden 45 attribute. Then export __tls_get_addr as __tls_get_addr_internal 46 for use from libc. We do not want to export __tls_get_addr, but we 47 do need to use it from libc when looking up the address of a TLS 48 variable. We don't use __tls_get_offset because it requires r12 to 49 be setup and that might not always be true. Either way it's more 50 optimal to use __tls_get_addr directly (that's what 51 __tls_get_offset does anyways). */ 52 strong_alias (__tls_get_addr, __tls_get_addr_internal_tmp); 53 versioned_symbol (ld, __tls_get_addr_internal_tmp, 54 __tls_get_addr_internal, GLIBC_PRIVATE); 55 56 /* The special thing about the s390 TLS ABI is that we do not have the 57 standard __tls_get_addr function but the __tls_get_offset function 58 which differs in two important aspects: 59 1) __tls_get_offset gets a got offset instead of a pointer to the 60 tls_index structure 61 2) __tls_get_offset returns the offset of the requested variable to 62 the thread descriptor instead of a pointer to the variable. 63 */ 64 # ifdef __s390x__ 65 __asm__("\n\ 66 .text\n\ 67 .globl __tls_get_offset\n\ 68 .type __tls_get_offset, @function\n\ 69 .align 4\n\ 70 __tls_get_offset:\n\ 71 la %r2,0(%r2,%r12)\n\ 72 jg __tls_get_addr\n\ 73 "); 74 # elif defined __s390__ 75 __asm__("\n\ 76 .text\n\ 77 .globl __tls_get_offset\n\ 78 .type __tls_get_offset, @function\n\ 79 .align 4\n\ 80 __tls_get_offset:\n\ 81 basr %r3,0\n\ 82 0: la %r2,0(%r2,%r12)\n\ 83 l %r4,1f-0b(%r3)\n\ 84 b 0(%r4,%r3)\n\ 85 1: .long __tls_get_addr - 0b\n\ 86 "); 87 # endif 88 # else /* IS_IN (rtld) */ 89 extern void *__tls_get_addr_internal (tls_index *ti); 90 # endif /* !IS_IN (rtld) */ 91 92 # define GET_ADDR_OFFSET \ 93 (ti->ti_offset - (unsigned long) __builtin_thread_pointer ()) 94 95 /* Use the privately exported __tls_get_addr_internal instead of 96 __tls_get_offset in order to avoid the __tls_get_offset special 97 linkage requiring the GOT pointer to be set up in r12. The 98 compiler will take care of setting up r12 only if itself issued the 99 __tls_get_offset call. */ 100 # define __TLS_GET_ADDR(__ti) \ 101 ({ __tls_get_addr_internal (__ti) \ 102 + (unsigned long) __builtin_thread_pointer (); }) 103 104 #endif 105