1/* Stack-aligning implementation of __tls_get_addr.  x86-64 version.
2   Copyright (C) 2017-2022 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#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
29ENTRY (__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
471:
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
60END (__tls_get_addr)
61#endif /* SHARED */
62