xref: /linux/arch/x86/entry/vdso/vdso-layout.lds.S (revision 7f71507851fc7764b36a3221839607d3a45c2025)
1/* SPDX-License-Identifier: GPL-2.0 */
2#include <asm/vdso.h>
3#include <asm/vdso/vsyscall.h>
4
5/*
6 * Linker script for vDSO.  This is an ELF shared object prelinked to
7 * its virtual address, and with only one read-only segment.
8 * This script controls its layout.
9 */
10
11SECTIONS
12{
13	/*
14	 * User/kernel shared data is before the vDSO.  This may be a little
15	 * uglier than putting it after the vDSO, but it avoids issues with
16	 * non-allocatable things that dangle past the end of the PT_LOAD
17	 * segment.
18	 */
19
20	vvar_start = . - __VVAR_PAGES * PAGE_SIZE;
21	vvar_page  = vvar_start;
22
23	vdso_rng_data = vvar_page + __VDSO_RND_DATA_OFFSET;
24
25	timens_page  = vvar_start + PAGE_SIZE;
26
27	vclock_pages = vvar_start + VDSO_NR_VCLOCK_PAGES * PAGE_SIZE;
28	pvclock_page = vclock_pages + VDSO_PAGE_PVCLOCK_OFFSET * PAGE_SIZE;
29	hvclock_page = vclock_pages + VDSO_PAGE_HVCLOCK_OFFSET * PAGE_SIZE;
30
31	. = SIZEOF_HEADERS;
32
33	.hash		: { *(.hash) }			:text
34	.gnu.hash	: { *(.gnu.hash) }
35	.dynsym		: { *(.dynsym) }
36	.dynstr		: { *(.dynstr) }
37	.gnu.version	: { *(.gnu.version) }
38	.gnu.version_d	: { *(.gnu.version_d) }
39	.gnu.version_r	: { *(.gnu.version_r) }
40
41	.dynamic	: { *(.dynamic) }		:text	:dynamic
42
43	.rodata		: {
44		*(.rodata*)
45		*(.data*)
46		*(.sdata*)
47		*(.got.plt) *(.got)
48		*(.gnu.linkonce.d.*)
49		*(.bss*)
50		*(.dynbss*)
51		*(.gnu.linkonce.b.*)
52	}						:text
53
54	/*
55	 * Discard .note.gnu.property sections which are unused and have
56	 * different alignment requirement from vDSO note sections.
57	 */
58	/DISCARD/ : {
59		*(.note.gnu.property)
60	}
61	.note		: { *(.note.*) }		:text	:note
62
63	.eh_frame_hdr	: { *(.eh_frame_hdr) }		:text	:eh_frame_hdr
64	.eh_frame	: { KEEP (*(.eh_frame)) }	:text
65
66
67	/*
68	 * Text is well-separated from actual data: there's plenty of
69	 * stuff that isn't used at runtime in between.
70	 */
71
72	.text		: {
73		*(.text*)
74	}						:text	=0x90909090,
75
76
77
78	.altinstructions	: { *(.altinstructions) }	:text
79	.altinstr_replacement	: { *(.altinstr_replacement) }	:text
80
81	__ex_table		: { *(__ex_table) }		:text
82
83	/DISCARD/ : {
84		*(.discard)
85		*(.discard.*)
86		*(__bug_table)
87	}
88}
89
90/*
91 * Very old versions of ld do not recognize this name token; use the constant.
92 */
93#define PT_GNU_EH_FRAME	0x6474e550
94
95/*
96 * We must supply the ELF program headers explicitly to get just one
97 * PT_LOAD segment, and set the flags explicitly to make segments read-only.
98 */
99PHDRS
100{
101	text		PT_LOAD		FLAGS(5) FILEHDR PHDRS; /* PF_R|PF_X */
102	dynamic		PT_DYNAMIC	FLAGS(4);		/* PF_R */
103	note		PT_NOTE		FLAGS(4);		/* PF_R */
104	eh_frame_hdr	PT_GNU_EH_FRAME;
105}
106