1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Author: Huacai Chen <chenhuacai@loongson.cn>
4 * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
5 */
6
7#include <linux/binfmts.h>
8#include <linux/elf.h>
9#include <linux/err.h>
10#include <linux/init.h>
11#include <linux/ioport.h>
12#include <linux/kernel.h>
13#include <linux/mm.h>
14#include <linux/random.h>
15#include <linux/sched.h>
16#include <linux/slab.h>
17#include <linux/vdso_datastore.h>
18
19#include <asm/page.h>
20#include <asm/vdso.h>
21#include <vdso/helpers.h>
22#include <vdso/vsyscall.h>
23#include <vdso/datapage.h>
24#include <generated/vdso-offsets.h>
25
26extern char vdso_start[], vdso_end[];
27
28static int vdso_mremap(const struct vm_special_mapping *sm, struct vm_area_struct *new_vma)
29{
30 current->mm->context.vdso = (void *)(new_vma->vm_start);
31
32 return 0;
33}
34
35struct loongarch_vdso_info vdso_info = {
36 .vdso = vdso_start,
37 .code_mapping = {
38 .name = "[vdso]",
39 .mremap = vdso_mremap,
40 },
41 .offset_sigreturn = vdso_offset_sigreturn,
42};
43
44static int __init init_vdso(void)
45{
46 unsigned long i, cpu, pfn;
47
48 BUG_ON(!PAGE_ALIGNED(vdso_info.vdso));
49
50 for_each_possible_cpu(cpu)
51 vdso_k_arch_data->pdata[cpu].node = cpu_to_node(cpu);
52
53 vdso_info.size = PAGE_ALIGN(vdso_end - vdso_start);
54 vdso_info.code_mapping.pages =
55 kcalloc(vdso_info.size / PAGE_SIZE, sizeof(struct page *), GFP_KERNEL);
56
57 if (!vdso_info.code_mapping.pages)
58 return -ENOMEM;
59
60 pfn = __phys_to_pfn(__pa_symbol(vdso_info.vdso));
61 for (i = 0; i < vdso_info.size / PAGE_SIZE; i++)
62 vdso_info.code_mapping.pages[i] = pfn_to_page(pfn + i);
63
64 return 0;
65}
66subsys_initcall(init_vdso);
67
68static unsigned long vdso_base(void)
69{
70 unsigned long base = STACK_TOP;
71
72 if (current->flags & PF_RANDOMIZE) {
73 base += get_random_u32_below(ceil: VDSO_RANDOMIZE_SIZE);
74 base = PAGE_ALIGN(base);
75 }
76
77 return base;
78}
79
80int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
81{
82 int ret;
83 unsigned long size, data_addr, vdso_addr;
84 struct mm_struct *mm = current->mm;
85 struct vm_area_struct *vma;
86 struct loongarch_vdso_info *info = current->thread.vdso;
87
88 if (mmap_write_lock_killable(mm))
89 return -EINTR;
90
91 /*
92 * Determine total area size. This includes the VDSO data itself
93 * and the data pages.
94 */
95 size = VVAR_SIZE + info->size;
96
97 data_addr = get_unmapped_area(NULL, addr: vdso_base(), len: size, pgoff: 0, flags: 0);
98 if (IS_ERR_VALUE(data_addr)) {
99 ret = data_addr;
100 goto out;
101 }
102
103 vma = vdso_install_vvar_mapping(mm, addr: data_addr);
104 if (IS_ERR(ptr: vma)) {
105 ret = PTR_ERR(ptr: vma);
106 goto out;
107 }
108
109 vdso_addr = data_addr + VVAR_SIZE;
110 vma = _install_special_mapping(mm, addr: vdso_addr, len: info->size,
111 VM_READ | VM_EXEC |
112 VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC |
113 VM_SEALED_SYSMAP,
114 spec: &info->code_mapping);
115 if (IS_ERR(ptr: vma)) {
116 ret = PTR_ERR(ptr: vma);
117 goto out;
118 }
119
120 mm->context.vdso = (void *)vdso_addr;
121 ret = 0;
122
123out:
124 mmap_write_unlock(mm);
125 return ret;
126}
127

source code of linux/arch/loongarch/kernel/vdso.c