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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Copyright (C) 2015 Imagination Technologies
4 * Author: Alex Smith <alex.smith@imgtec.com>
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/timekeeper_internal.h>
18
19#include <asm/abi.h>
20#include <asm/mips-cps.h>
21#include <asm/page.h>
22#include <asm/vdso.h>
23#include <vdso/helpers.h>
24#include <vdso/vsyscall.h>
25
26/* Kernel-provided data used by the VDSO. */
27static union mips_vdso_data mips_vdso_data __page_aligned_data;
28struct vdso_data *vdso_data = mips_vdso_data.data;
29
30/*
31 * Mapping for the VDSO data/GIC pages. The real pages are mapped manually, as
32 * what we map and where within the area they are mapped is determined at
33 * runtime.
34 */
35static struct page *no_pages[] = { NULL };
36static struct vm_special_mapping vdso_vvar_mapping = {
37 .name = "[vvar]",
38 .pages = no_pages,
39};
40
41static void __init init_vdso_image(struct mips_vdso_image *image)
42{
43 unsigned long num_pages, i;
44 unsigned long data_pfn;
45
46 BUG_ON(!PAGE_ALIGNED(image->data));
47 BUG_ON(!PAGE_ALIGNED(image->size));
48
49 num_pages = image->size / PAGE_SIZE;
50
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);
54}
55
56static int __init init_vdso(void)
57{
58 init_vdso_image(&vdso_image);
59
60#ifdef CONFIG_MIPS32_O32
61 init_vdso_image(&vdso_image_o32);
62#endif
63
64#ifdef CONFIG_MIPS32_N32
65 init_vdso_image(&vdso_image_n32);
66#endif
67
68 return 0;
69}
70subsys_initcall(init_vdso);
71
72static unsigned long vdso_base(void)
73{
74 unsigned long base;
75
76 /* Skip the delay slot emulation page */
77 base = STACK_TOP + PAGE_SIZE;
78
79 if (current->flags & PF_RANDOMIZE) {
80 base += get_random_int() & (VDSO_RANDOMIZE_SIZE - 1);
81 base = PAGE_ALIGN(base);
82 }
83
84 return base;
85}
86
87int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
88{
89 struct mips_vdso_image *image = current->thread.abi->vdso;
90 struct mm_struct *mm = current->mm;
91 unsigned long gic_size, vvar_size, size, base, data_addr, vdso_addr, gic_pfn;
92 struct vm_area_struct *vma;
93 int ret;
94
95 if (down_write_killable(&mm->mmap_sem))
96 return -EINTR;
97
98 /* Map delay slot emulation page */
99 base = mmap_region(NULL, STACK_TOP, PAGE_SIZE,
100 VM_READ | VM_EXEC |
101 VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC,
102 0, NULL);
103 if (IS_ERR_VALUE(base)) {
104 ret = base;
105 goto out;
106 }
107
108 /*
109 * Determine total area size. This includes the VDSO data itself, the
110 * data page, and the GIC user page if present. Always create a mapping
111 * for the GIC user area if the GIC is present regardless of whether it
112 * is the current clocksource, in case it comes into use later on. We
113 * only map a page even though the total area is 64K, as we only need
114 * the counter registers at the start.
115 */
116 gic_size = mips_gic_present() ? PAGE_SIZE : 0;
117 vvar_size = gic_size + PAGE_SIZE;
118 size = vvar_size + image->size;
119
120 /*
121 * Find a region that's large enough for us to perform the
122 * colour-matching alignment below.
123 */
124 if (cpu_has_dc_aliases)
125 size += shm_align_mask + 1;
126
127 base = get_unmapped_area(NULL, vdso_base(), size, 0, 0);
128 if (IS_ERR_VALUE(base)) {
129 ret = base;
130 goto out;
131 }
132
133 /*
134 * If we suffer from dcache aliasing, ensure that the VDSO data page
135 * mapping is coloured the same as the kernel's mapping of that memory.
136 * This ensures that when the kernel updates the VDSO data userland
137 * will observe it without requiring cache invalidations.
138 */
139 if (cpu_has_dc_aliases) {
140 base = __ALIGN_MASK(base, shm_align_mask);
141 base += ((unsigned long)vdso_data - gic_size) & shm_align_mask;
142 }
143
144 data_addr = base + gic_size;
145 vdso_addr = data_addr + PAGE_SIZE;
146
147 vma = _install_special_mapping(mm, base, vvar_size,
148 VM_READ | VM_MAYREAD,
149 &vdso_vvar_mapping);
150 if (IS_ERR(vma)) {
151 ret = PTR_ERR(vma);
152 goto out;
153 }
154
155 /* Map GIC user page. */
156 if (gic_size) {
157 gic_pfn = virt_to_phys(mips_gic_base + MIPS_GIC_USER_OFS) >> PAGE_SHIFT;
158
159 ret = io_remap_pfn_range(vma, base, gic_pfn, gic_size,
160 pgprot_noncached(PAGE_READONLY));
161 if (ret)
162 goto out;
163 }
164
165 /* Map data page. */
166 ret = remap_pfn_range(vma, data_addr,
167 virt_to_phys(vdso_data) >> PAGE_SHIFT,
168 PAGE_SIZE, PAGE_READONLY);
169 if (ret)
170 goto out;
171
172 /* Map VDSO image. */
173 vma = _install_special_mapping(mm, vdso_addr, image->size,
174 VM_READ | VM_EXEC |
175 VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC,
176 &image->mapping);
177 if (IS_ERR(vma)) {
178 ret = PTR_ERR(vma);
179 goto out;
180 }
181
182 mm->context.vdso = (void *)vdso_addr;
183 ret = 0;
184
185out:
186 up_write(&mm->mmap_sem);
187 return ret;
188}
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Copyright (C) 2015 Imagination Technologies
4 * Author: Alex Smith <alex.smith@imgtec.com>
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
18#include <asm/abi.h>
19#include <asm/mips-cps.h>
20#include <asm/page.h>
21#include <asm/vdso.h>
22#include <vdso/helpers.h>
23#include <vdso/vsyscall.h>
24
25/* Kernel-provided data used by the VDSO. */
26static union vdso_data_store mips_vdso_data __page_aligned_data;
27struct vdso_data *vdso_data = mips_vdso_data.data;
28
29/*
30 * Mapping for the VDSO data/GIC pages. The real pages are mapped manually, as
31 * what we map and where within the area they are mapped is determined at
32 * runtime.
33 */
34static struct page *no_pages[] = { NULL };
35static struct vm_special_mapping vdso_vvar_mapping = {
36 .name = "[vvar]",
37 .pages = no_pages,
38};
39
40static void __init init_vdso_image(struct mips_vdso_image *image)
41{
42 unsigned long num_pages, i;
43 unsigned long data_pfn;
44
45 BUG_ON(!PAGE_ALIGNED(image->data));
46 BUG_ON(!PAGE_ALIGNED(image->size));
47
48 num_pages = image->size / PAGE_SIZE;
49
50 data_pfn = __phys_to_pfn(__pa_symbol(image->data));
51 for (i = 0; i < num_pages; i++)
52 image->mapping.pages[i] = pfn_to_page(data_pfn + i);
53}
54
55static int __init init_vdso(void)
56{
57 init_vdso_image(&vdso_image);
58
59#ifdef CONFIG_MIPS32_O32
60 init_vdso_image(&vdso_image_o32);
61#endif
62
63#ifdef CONFIG_MIPS32_N32
64 init_vdso_image(&vdso_image_n32);
65#endif
66
67 return 0;
68}
69subsys_initcall(init_vdso);
70
71static unsigned long vdso_base(void)
72{
73 unsigned long base = STACK_TOP;
74
75 if (IS_ENABLED(CONFIG_MIPS_FP_SUPPORT)) {
76 /* Skip the delay slot emulation page */
77 base += PAGE_SIZE;
78 }
79
80 if (current->flags & PF_RANDOMIZE) {
81 base += get_random_u32_below(VDSO_RANDOMIZE_SIZE);
82 base = PAGE_ALIGN(base);
83 }
84
85 return base;
86}
87
88int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
89{
90 struct mips_vdso_image *image = current->thread.abi->vdso;
91 struct mm_struct *mm = current->mm;
92 unsigned long gic_size, vvar_size, size, base, data_addr, vdso_addr, gic_pfn, gic_base;
93 struct vm_area_struct *vma;
94 int ret;
95
96 if (mmap_write_lock_killable(mm))
97 return -EINTR;
98
99 if (IS_ENABLED(CONFIG_MIPS_FP_SUPPORT)) {
100 /* Map delay slot emulation page */
101 base = mmap_region(NULL, STACK_TOP, PAGE_SIZE,
102 VM_READ | VM_EXEC |
103 VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC,
104 0, NULL);
105 if (IS_ERR_VALUE(base)) {
106 ret = base;
107 goto out;
108 }
109 }
110
111 /*
112 * Determine total area size. This includes the VDSO data itself, the
113 * data page, and the GIC user page if present. Always create a mapping
114 * for the GIC user area if the GIC is present regardless of whether it
115 * is the current clocksource, in case it comes into use later on. We
116 * only map a page even though the total area is 64K, as we only need
117 * the counter registers at the start.
118 */
119 gic_size = mips_gic_present() ? PAGE_SIZE : 0;
120 vvar_size = gic_size + PAGE_SIZE;
121 size = vvar_size + image->size;
122
123 /*
124 * Find a region that's large enough for us to perform the
125 * colour-matching alignment below.
126 */
127 if (cpu_has_dc_aliases)
128 size += shm_align_mask + 1;
129
130 base = get_unmapped_area(NULL, vdso_base(), size, 0, 0);
131 if (IS_ERR_VALUE(base)) {
132 ret = base;
133 goto out;
134 }
135
136 /*
137 * If we suffer from dcache aliasing, ensure that the VDSO data page
138 * mapping is coloured the same as the kernel's mapping of that memory.
139 * This ensures that when the kernel updates the VDSO data userland
140 * will observe it without requiring cache invalidations.
141 */
142 if (cpu_has_dc_aliases) {
143 base = __ALIGN_MASK(base, shm_align_mask);
144 base += ((unsigned long)vdso_data - gic_size) & shm_align_mask;
145 }
146
147 data_addr = base + gic_size;
148 vdso_addr = data_addr + PAGE_SIZE;
149
150 vma = _install_special_mapping(mm, base, vvar_size,
151 VM_READ | VM_MAYREAD,
152 &vdso_vvar_mapping);
153 if (IS_ERR(vma)) {
154 ret = PTR_ERR(vma);
155 goto out;
156 }
157
158 /* Map GIC user page. */
159 if (gic_size) {
160 gic_base = (unsigned long)mips_gic_base + MIPS_GIC_USER_OFS;
161 gic_pfn = PFN_DOWN(__pa(gic_base));
162
163 ret = io_remap_pfn_range(vma, base, gic_pfn, gic_size,
164 pgprot_noncached(vma->vm_page_prot));
165 if (ret)
166 goto out;
167 }
168
169 /* Map data page. */
170 ret = remap_pfn_range(vma, data_addr,
171 virt_to_phys(vdso_data) >> PAGE_SHIFT,
172 PAGE_SIZE, vma->vm_page_prot);
173 if (ret)
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 }
185
186 mm->context.vdso = (void *)vdso_addr;
187 ret = 0;
188
189out:
190 mmap_write_unlock(mm);
191 return ret;
192}