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
26 extern char vdso_start[], vdso_end[];
27
vdso_mremap(const struct vm_special_mapping * sm,struct vm_area_struct * new_vma)28 static 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
35 struct 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
init_vdso(void)44 static 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 pfn = __phys_to_pfn(__pa_symbol(vdso_info.vdso));
58 for (i = 0; i < vdso_info.size / PAGE_SIZE; i++)
59 vdso_info.code_mapping.pages[i] = pfn_to_page(pfn + i);
60
61 return 0;
62 }
63 subsys_initcall(init_vdso);
64
vdso_base(void)65 static unsigned long vdso_base(void)
66 {
67 unsigned long base = STACK_TOP;
68
69 if (current->flags & PF_RANDOMIZE) {
70 base += get_random_u32_below(VDSO_RANDOMIZE_SIZE);
71 base = PAGE_ALIGN(base);
72 }
73
74 return base;
75 }
76
arch_setup_additional_pages(struct linux_binprm * bprm,int uses_interp)77 int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
78 {
79 int ret;
80 unsigned long size, data_addr, vdso_addr;
81 struct mm_struct *mm = current->mm;
82 struct vm_area_struct *vma;
83 struct loongarch_vdso_info *info = current->thread.vdso;
84
85 if (mmap_write_lock_killable(mm))
86 return -EINTR;
87
88 /*
89 * Determine total area size. This includes the VDSO data itself
90 * and the data pages.
91 */
92 size = VVAR_SIZE + info->size;
93
94 data_addr = get_unmapped_area(NULL, vdso_base(), size, 0, 0);
95 if (IS_ERR_VALUE(data_addr)) {
96 ret = data_addr;
97 goto out;
98 }
99
100 vma = vdso_install_vvar_mapping(mm, data_addr);
101 if (IS_ERR(vma)) {
102 ret = PTR_ERR(vma);
103 goto out;
104 }
105
106 vdso_addr = data_addr + VVAR_SIZE;
107 vma = _install_special_mapping(mm, vdso_addr, info->size,
108 VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC,
109 &info->code_mapping);
110 if (IS_ERR(vma)) {
111 ret = PTR_ERR(vma);
112 goto out;
113 }
114
115 mm->context.vdso = (void *)vdso_addr;
116 ret = 0;
117
118 out:
119 mmap_write_unlock(mm);
120 return ret;
121 }
122