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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#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 = STACK_TOP;
75
76 if (IS_ENABLED(CONFIG_MIPS_FP_SUPPORT)) {
77 /* Skip the delay slot emulation page */
78 base += PAGE_SIZE;
79 }
80
81 if (current->flags & PF_RANDOMIZE) {
82 base += get_random_u32_below(VDSO_RANDOMIZE_SIZE);
83 base = PAGE_ALIGN(base);
84 }
85
86 return base;
87}
88
89int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
90{
91 struct mips_vdso_image *image = current->thread.abi->vdso;
92 struct mm_struct *mm = current->mm;
93 unsigned long gic_size, vvar_size, size, base, data_addr, vdso_addr, gic_pfn, gic_base;
94 struct vm_area_struct *vma;
95 int ret;
96
97 if (mmap_write_lock_killable(mm))
98 return -EINTR;
99
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 }
110 }
111
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 */
120 gic_size = mips_gic_present() ? PAGE_SIZE : 0;
121 vvar_size = gic_size + PAGE_SIZE;
122 size = vvar_size + image->size;
123
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
131 base = get_unmapped_area(NULL, vdso_base(), size, 0, 0);
132 if (IS_ERR_VALUE(base)) {
133 ret = base;
134 goto out;
135 }
136
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);
145 base += ((unsigned long)vdso_data - gic_size) & shm_align_mask;
146 }
147
148 data_addr = base + gic_size;
149 vdso_addr = data_addr + PAGE_SIZE;
150
151 vma = _install_special_mapping(mm, base, vvar_size,
152 VM_READ | VM_MAYREAD,
153 &vdso_vvar_mapping);
154 if (IS_ERR(vma)) {
155 ret = PTR_ERR(vma);
156 goto out;
157 }
158
159 /* Map GIC user page. */
160 if (gic_size) {
161 gic_base = (unsigned long)mips_gic_base + MIPS_GIC_USER_OFS;
162 gic_pfn = PFN_DOWN(__pa(gic_base));
163
164 ret = io_remap_pfn_range(vma, base, gic_pfn, gic_size,
165 pgprot_noncached(vma->vm_page_prot));
166 if (ret)
167 goto out;
168 }
169
170 /* Map data page. */
171 ret = remap_pfn_range(vma, data_addr,
172 virt_to_phys(vdso_data) >> PAGE_SHIFT,
173 PAGE_SIZE, vma->vm_page_prot);
174 if (ret)
175 goto out;
176
177 /* Map VDSO image. */
178 vma = _install_special_mapping(mm, vdso_addr, image->size,
179 VM_READ | VM_EXEC |
180 VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC,
181 &image->mapping);
182 if (IS_ERR(vma)) {
183 ret = PTR_ERR(vma);
184 goto out;
185 }
186
187 mm->context.vdso = (void *)vdso_addr;
188 ret = 0;
189
190out:
191 mmap_write_unlock(mm);
192 return ret;
193}