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031e519c | 1 | /* Stack-aligning implementation of __tls_get_addr. x86-64 version. |
2b778ceb | 2 | Copyright (C) 2017-2021 Free Software Foundation, Inc. |
031e519c L |
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 | |
5a82c748 | 17 | <https://www.gnu.org/licenses/>. */ |
031e519c L |
18 | |
19 | #ifdef SHARED | |
20 | ||
21 | # include <sysdep.h> | |
22 | # include "tlsdesc.h" | |
23 | # include "rtld-offsets.h" | |
24 | ||
25 | /* See __tls_get_addr and __tls_get_addr_slow in dl-tls.c. This function | |
26 | call __tls_get_addr_slow on both slow paths. It realigns the stack | |
27 | before the call to work around GCC PR58066. */ | |
28 | ||
29 | ENTRY (__tls_get_addr) | |
30 | mov %fs:DTV_OFFSET, %RDX_LP | |
31 | mov GL_TLS_GENERATION_OFFSET+_rtld_local(%rip), %RAX_LP | |
32 | /* GL(dl_tls_generation) == dtv[0].counter */ | |
33 | cmp %RAX_LP, (%rdx) | |
34 | jne 1f | |
35 | mov TI_MODULE_OFFSET(%rdi), %RAX_LP | |
36 | /* dtv[ti->ti_module] */ | |
37 | # ifdef __LP64__ | |
38 | salq $4, %rax | |
39 | movq (%rdx,%rax), %rax | |
40 | # else | |
41 | movl (%rdx,%rax, 8), %eax | |
42 | # endif | |
43 | cmp $-1, %RAX_LP | |
44 | je 1f | |
45 | add TI_OFFSET_OFFSET(%rdi), %RAX_LP | |
46 | ret | |
47 | 1: | |
48 | /* On the slow path, align the stack. */ | |
49 | pushq %rbp | |
50 | cfi_def_cfa_offset (16) | |
51 | cfi_offset (%rbp, -16) | |
52 | mov %RSP_LP, %RBP_LP | |
53 | cfi_def_cfa_register (%rbp) | |
54 | and $-16, %RSP_LP | |
55 | call __tls_get_addr_slow | |
56 | mov %RBP_LP, %RSP_LP | |
57 | popq %rbp | |
58 | cfi_def_cfa (%rsp, 8) | |
59 | ret | |
60 | END (__tls_get_addr) | |
61 | #endif /* SHARED */ |