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1/*
2 * Copyright (C) 2004 Benjamin Herrenschmidt, IBM Corp.
3 * <benh@kernel.crashing.org>
4 * Copyright (C) 2012 ARM Limited
5 * Copyright (C) 2015 Regents of the University of California
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program. If not, see <http://www.gnu.org/licenses/>.
18 */
19
20#include <linux/mm.h>
21#include <linux/slab.h>
22#include <linux/binfmts.h>
23#include <linux/err.h>
24
25#include <asm/vdso.h>
26
27extern char vdso_start[], vdso_end[];
28
29static unsigned int vdso_pages;
30static struct page **vdso_pagelist;
31
32/*
33 * The vDSO data page.
34 */
35static union {
36 struct vdso_data data;
37 u8 page[PAGE_SIZE];
38} vdso_data_store __page_aligned_data;
39struct vdso_data *vdso_data = &vdso_data_store.data;
40
41static int __init vdso_init(void)
42{
43 unsigned int i;
44
45 vdso_pages = (vdso_end - vdso_start) >> PAGE_SHIFT;
46 vdso_pagelist =
47 kcalloc(vdso_pages + 1, sizeof(struct page *), GFP_KERNEL);
48 if (unlikely(vdso_pagelist == NULL)) {
49 pr_err("vdso: pagelist allocation failed\n");
50 return -ENOMEM;
51 }
52
53 for (i = 0; i < vdso_pages; i++) {
54 struct page *pg;
55
56 pg = virt_to_page(vdso_start + (i << PAGE_SHIFT));
57 ClearPageReserved(pg);
58 vdso_pagelist[i] = pg;
59 }
60 vdso_pagelist[i] = virt_to_page(vdso_data);
61
62 return 0;
63}
64arch_initcall(vdso_init);
65
66int arch_setup_additional_pages(struct linux_binprm *bprm,
67 int uses_interp)
68{
69 struct mm_struct *mm = current->mm;
70 unsigned long vdso_base, vdso_len;
71 int ret;
72
73 vdso_len = (vdso_pages + 1) << PAGE_SHIFT;
74
75 down_write(&mm->mmap_sem);
76 vdso_base = get_unmapped_area(NULL, 0, vdso_len, 0, 0);
77 if (IS_ERR_VALUE(vdso_base)) {
78 ret = vdso_base;
79 goto end;
80 }
81
82 /*
83 * Put vDSO base into mm struct. We need to do this before calling
84 * install_special_mapping or the perf counter mmap tracking code
85 * will fail to recognise it as a vDSO (since arch_vma_name fails).
86 */
87 mm->context.vdso = (void *)vdso_base;
88
89 ret = install_special_mapping(mm, vdso_base, vdso_len,
90 (VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC),
91 vdso_pagelist);
92
93 if (unlikely(ret))
94 mm->context.vdso = NULL;
95
96end:
97 up_write(&mm->mmap_sem);
98 return ret;
99}
100
101const char *arch_vma_name(struct vm_area_struct *vma)
102{
103 if (vma->vm_mm && (vma->vm_start == (long)vma->vm_mm->context.vdso))
104 return "[vdso]";
105 return NULL;
106}
107
108/*
109 * Function stubs to prevent linker errors when AT_SYSINFO_EHDR is defined
110 */
111
112int in_gate_area_no_mm(unsigned long addr)
113{
114 return 0;
115}
116
117int in_gate_area(struct mm_struct *mm, unsigned long addr)
118{
119 return 0;
120}
121
122struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
123{
124 return NULL;
125}
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) 2004 Benjamin Herrenschmidt, IBM Corp.
4 * <benh@kernel.crashing.org>
5 * Copyright (C) 2012 ARM Limited
6 * Copyright (C) 2015 Regents of the University of California
7 */
8
9#include <linux/elf.h>
10#include <linux/mm.h>
11#include <linux/slab.h>
12#include <linux/binfmts.h>
13#include <linux/err.h>
14#include <asm/page.h>
15#include <asm/vdso.h>
16
17#ifdef CONFIG_GENERIC_TIME_VSYSCALL
18#include <vdso/datapage.h>
19#else
20struct vdso_data {
21};
22#endif
23
24extern char vdso_start[], vdso_end[];
25
26enum vvar_pages {
27 VVAR_DATA_PAGE_OFFSET,
28 VVAR_NR_PAGES,
29};
30
31#define VVAR_SIZE (VVAR_NR_PAGES << PAGE_SHIFT)
32
33static unsigned int vdso_pages __ro_after_init;
34static struct page **vdso_pagelist __ro_after_init;
35
36/*
37 * The vDSO data page.
38 */
39static union {
40 struct vdso_data data;
41 u8 page[PAGE_SIZE];
42} vdso_data_store __page_aligned_data;
43struct vdso_data *vdso_data = &vdso_data_store.data;
44
45static int __init vdso_init(void)
46{
47 unsigned int i;
48
49 vdso_pages = (vdso_end - vdso_start) >> PAGE_SHIFT;
50 vdso_pagelist =
51 kcalloc(vdso_pages + VVAR_NR_PAGES, sizeof(struct page *), GFP_KERNEL);
52 if (unlikely(vdso_pagelist == NULL)) {
53 pr_err("vdso: pagelist allocation failed\n");
54 return -ENOMEM;
55 }
56
57 for (i = 0; i < vdso_pages; i++) {
58 struct page *pg;
59
60 pg = virt_to_page(vdso_start + (i << PAGE_SHIFT));
61 vdso_pagelist[i] = pg;
62 }
63 vdso_pagelist[i] = virt_to_page(vdso_data);
64
65 return 0;
66}
67arch_initcall(vdso_init);
68
69int arch_setup_additional_pages(struct linux_binprm *bprm,
70 int uses_interp)
71{
72 struct mm_struct *mm = current->mm;
73 unsigned long vdso_base, vdso_len;
74 int ret;
75
76 BUILD_BUG_ON(VVAR_NR_PAGES != __VVAR_PAGES);
77
78 vdso_len = (vdso_pages + VVAR_NR_PAGES) << PAGE_SHIFT;
79
80 if (mmap_write_lock_killable(mm))
81 return -EINTR;
82
83 vdso_base = get_unmapped_area(NULL, 0, vdso_len, 0, 0);
84 if (IS_ERR_VALUE(vdso_base)) {
85 ret = vdso_base;
86 goto end;
87 }
88
89 mm->context.vdso = NULL;
90 ret = install_special_mapping(mm, vdso_base, VVAR_SIZE,
91 (VM_READ | VM_MAYREAD), &vdso_pagelist[vdso_pages]);
92 if (unlikely(ret))
93 goto end;
94
95 ret =
96 install_special_mapping(mm, vdso_base + VVAR_SIZE,
97 vdso_pages << PAGE_SHIFT,
98 (VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC),
99 vdso_pagelist);
100
101 if (unlikely(ret))
102 goto end;
103
104 /*
105 * Put vDSO base into mm struct. We need to do this before calling
106 * install_special_mapping or the perf counter mmap tracking code
107 * will fail to recognise it as a vDSO (since arch_vma_name fails).
108 */
109 mm->context.vdso = (void *)vdso_base + VVAR_SIZE;
110
111end:
112 mmap_write_unlock(mm);
113 return ret;
114}
115
116const char *arch_vma_name(struct vm_area_struct *vma)
117{
118 if (vma->vm_mm && (vma->vm_start == (long)vma->vm_mm->context.vdso))
119 return "[vdso]";
120 if (vma->vm_mm && (vma->vm_start ==
121 (long)vma->vm_mm->context.vdso - VVAR_SIZE))
122 return "[vdso_data]";
123 return NULL;
124}