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2874c5fd | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
c52d0d30 | 2 | /* |
ebb5e78c AS |
3 | * Copyright (C) 2015 Imagination Technologies |
4 | * Author: Alex Smith <alex.smith@imgtec.com> | |
c52d0d30 DD |
5 | */ |
6 | ||
c52d0d30 DD |
7 | #include <linux/binfmts.h> |
8 | #include <linux/elf.h> | |
ebb5e78c AS |
9 | #include <linux/err.h> |
10 | #include <linux/init.h> | |
a7f4df4e | 11 | #include <linux/ioport.h> |
0f02cfbc | 12 | #include <linux/kernel.h> |
ebb5e78c | 13 | #include <linux/mm.h> |
ea7e0480 | 14 | #include <linux/random.h> |
ebb5e78c AS |
15 | #include <linux/sched.h> |
16 | #include <linux/slab.h> | |
a7f4df4e | 17 | #include <linux/timekeeper_internal.h> |
c52d0d30 | 18 | |
ebb5e78c | 19 | #include <asm/abi.h> |
00578cd8 | 20 | #include <asm/mips-cps.h> |
0f02cfbc | 21 | #include <asm/page.h> |
c52d0d30 | 22 | #include <asm/vdso.h> |
24640f23 VF |
23 | #include <vdso/helpers.h> |
24 | #include <vdso/vsyscall.h> | |
ebb5e78c AS |
25 | |
26 | /* Kernel-provided data used by the VDSO. */ | |
24640f23 VF |
27 | static union mips_vdso_data mips_vdso_data __page_aligned_data; |
28 | struct vdso_data *vdso_data = mips_vdso_data.data; | |
c52d0d30 DD |
29 | |
30 | /* | |
a7f4df4e | 31 | * Mapping for the VDSO data/GIC pages. The real pages are mapped manually, as |
ebb5e78c AS |
32 | * what we map and where within the area they are mapped is determined at |
33 | * runtime. | |
c52d0d30 | 34 | */ |
ebb5e78c AS |
35 | static struct page *no_pages[] = { NULL }; |
36 | static struct vm_special_mapping vdso_vvar_mapping = { | |
37 | .name = "[vvar]", | |
38 | .pages = no_pages, | |
39 | }; | |
c52d0d30 | 40 | |
ebb5e78c | 41 | static void __init init_vdso_image(struct mips_vdso_image *image) |
c52d0d30 | 42 | { |
ebb5e78c | 43 | unsigned long num_pages, i; |
554af0c3 | 44 | unsigned long data_pfn; |
ebb5e78c AS |
45 | |
46 | BUG_ON(!PAGE_ALIGNED(image->data)); | |
47 | BUG_ON(!PAGE_ALIGNED(image->size)); | |
48 | ||
49 | num_pages = image->size / PAGE_SIZE; | |
50 | ||
554af0c3 JH |
51 | data_pfn = __phys_to_pfn(__pa_symbol(image->data)); |
52 | for (i = 0; i < num_pages; i++) | |
53 | image->mapping.pages[i] = pfn_to_page(data_pfn + i); | |
c52d0d30 DD |
54 | } |
55 | ||
56 | static int __init init_vdso(void) | |
57 | { | |
ebb5e78c AS |
58 | init_vdso_image(&vdso_image); |
59 | ||
60 | #ifdef CONFIG_MIPS32_O32 | |
61 | init_vdso_image(&vdso_image_o32); | |
c52d0d30 DD |
62 | #endif |
63 | ||
ebb5e78c AS |
64 | #ifdef CONFIG_MIPS32_N32 |
65 | init_vdso_image(&vdso_image_n32); | |
66 | #endif | |
c52d0d30 | 67 | |
c52d0d30 DD |
68 | return 0; |
69 | } | |
1ed84537 | 70 | subsys_initcall(init_vdso); |
c52d0d30 | 71 | |
ea7e0480 PB |
72 | static unsigned long vdso_base(void) |
73 | { | |
aebdc6ff | 74 | unsigned long base = STACK_TOP; |
ea7e0480 | 75 | |
aebdc6ff YZ |
76 | if (IS_ENABLED(CONFIG_MIPS_FP_SUPPORT)) { |
77 | /* Skip the delay slot emulation page */ | |
78 | base += PAGE_SIZE; | |
79 | } | |
ea7e0480 PB |
80 | |
81 | if (current->flags & PF_RANDOMIZE) { | |
82 | base += get_random_int() & (VDSO_RANDOMIZE_SIZE - 1); | |
83 | base = PAGE_ALIGN(base); | |
84 | } | |
85 | ||
86 | return base; | |
87 | } | |
88 | ||
c52d0d30 DD |
89 | int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp) |
90 | { | |
ebb5e78c | 91 | struct mips_vdso_image *image = current->thread.abi->vdso; |
c52d0d30 | 92 | struct mm_struct *mm = current->mm; |
00578cd8 | 93 | unsigned long gic_size, vvar_size, size, base, data_addr, vdso_addr, gic_pfn; |
ebb5e78c AS |
94 | struct vm_area_struct *vma; |
95 | int ret; | |
c52d0d30 | 96 | |
d8ed45c5 | 97 | if (mmap_write_lock_killable(mm)) |
69048176 | 98 | return -EINTR; |
c52d0d30 | 99 | |
aebdc6ff YZ |
100 | if (IS_ENABLED(CONFIG_MIPS_FP_SUPPORT)) { |
101 | /* Map delay slot emulation page */ | |
102 | base = mmap_region(NULL, STACK_TOP, PAGE_SIZE, | |
103 | VM_READ | VM_EXEC | | |
104 | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC, | |
105 | 0, NULL); | |
106 | if (IS_ERR_VALUE(base)) { | |
107 | ret = base; | |
108 | goto out; | |
109 | } | |
432c6bac PB |
110 | } |
111 | ||
a7f4df4e AS |
112 | /* |
113 | * Determine total area size. This includes the VDSO data itself, the | |
114 | * data page, and the GIC user page if present. Always create a mapping | |
115 | * for the GIC user area if the GIC is present regardless of whether it | |
116 | * is the current clocksource, in case it comes into use later on. We | |
117 | * only map a page even though the total area is 64K, as we only need | |
118 | * the counter registers at the start. | |
119 | */ | |
00578cd8 | 120 | gic_size = mips_gic_present() ? PAGE_SIZE : 0; |
a7f4df4e AS |
121 | vvar_size = gic_size + PAGE_SIZE; |
122 | size = vvar_size + image->size; | |
123 | ||
0f02cfbc PB |
124 | /* |
125 | * Find a region that's large enough for us to perform the | |
126 | * colour-matching alignment below. | |
127 | */ | |
128 | if (cpu_has_dc_aliases) | |
129 | size += shm_align_mask + 1; | |
130 | ||
ea7e0480 | 131 | base = get_unmapped_area(NULL, vdso_base(), size, 0, 0); |
ebb5e78c AS |
132 | if (IS_ERR_VALUE(base)) { |
133 | ret = base; | |
134 | goto out; | |
c52d0d30 DD |
135 | } |
136 | ||
0f02cfbc PB |
137 | /* |
138 | * If we suffer from dcache aliasing, ensure that the VDSO data page | |
139 | * mapping is coloured the same as the kernel's mapping of that memory. | |
140 | * This ensures that when the kernel updates the VDSO data userland | |
141 | * will observe it without requiring cache invalidations. | |
142 | */ | |
143 | if (cpu_has_dc_aliases) { | |
144 | base = __ALIGN_MASK(base, shm_align_mask); | |
24640f23 | 145 | base += ((unsigned long)vdso_data - gic_size) & shm_align_mask; |
0f02cfbc PB |
146 | } |
147 | ||
a7f4df4e AS |
148 | data_addr = base + gic_size; |
149 | vdso_addr = data_addr + PAGE_SIZE; | |
ebb5e78c | 150 | |
a7f4df4e | 151 | vma = _install_special_mapping(mm, base, vvar_size, |
ebb5e78c AS |
152 | VM_READ | VM_MAYREAD, |
153 | &vdso_vvar_mapping); | |
154 | if (IS_ERR(vma)) { | |
155 | ret = PTR_ERR(vma); | |
156 | goto out; | |
157 | } | |
c52d0d30 | 158 | |
a7f4df4e AS |
159 | /* Map GIC user page. */ |
160 | if (gic_size) { | |
00578cd8 | 161 | gic_pfn = virt_to_phys(mips_gic_base + MIPS_GIC_USER_OFS) >> PAGE_SHIFT; |
a7f4df4e | 162 | |
00578cd8 | 163 | ret = io_remap_pfn_range(vma, base, gic_pfn, gic_size, |
a7f4df4e AS |
164 | pgprot_noncached(PAGE_READONLY)); |
165 | if (ret) | |
166 | goto out; | |
167 | } | |
168 | ||
ebb5e78c | 169 | /* Map data page. */ |
a7f4df4e | 170 | ret = remap_pfn_range(vma, data_addr, |
24640f23 | 171 | virt_to_phys(vdso_data) >> PAGE_SHIFT, |
ebb5e78c | 172 | PAGE_SIZE, PAGE_READONLY); |
c52d0d30 | 173 | if (ret) |
ebb5e78c AS |
174 | goto out; |
175 | ||
176 | /* Map VDSO image. */ | |
177 | vma = _install_special_mapping(mm, vdso_addr, image->size, | |
178 | VM_READ | VM_EXEC | | |
179 | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC, | |
180 | &image->mapping); | |
181 | if (IS_ERR(vma)) { | |
182 | ret = PTR_ERR(vma); | |
183 | goto out; | |
184 | } | |
c52d0d30 | 185 | |
ebb5e78c AS |
186 | mm->context.vdso = (void *)vdso_addr; |
187 | ret = 0; | |
c52d0d30 | 188 | |
ebb5e78c | 189 | out: |
d8ed45c5 | 190 | mmap_write_unlock(mm); |
c52d0d30 DD |
191 | return ret; |
192 | } |