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1 | /* Thread-local storage handling in the ELF dynamic linker. s390 version. |
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2 | Copyright (C) 2003-2022 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 |
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