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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/*
2 * This file is subject to the terms and conditions of the GNU General Public
3 * License. See the file "COPYING" in the main directory of this archive
4 * for more details.
5 *
6 * Copyright (C) 2009, 2010 Cavium Networks, Inc.
7 */
8
9
10#include <linux/kernel.h>
11#include <linux/err.h>
12#include <linux/sched.h>
13#include <linux/mm.h>
14#include <linux/init.h>
15#include <linux/binfmts.h>
16#include <linux/elf.h>
17#include <linux/vmalloc.h>
18#include <linux/unistd.h>
19
20#include <asm/vdso.h>
21#include <asm/uasm.h>
22
23/*
24 * Including <asm/unistd.h> would give use the 64-bit syscall numbers ...
25 */
26#define __NR_O32_sigreturn 4119
27#define __NR_O32_rt_sigreturn 4193
28#define __NR_N32_rt_sigreturn 6211
29
30static struct page *vdso_page;
31
32static void __init install_trampoline(u32 *tramp, unsigned int sigreturn)
33{
34 uasm_i_addiu(&tramp, 2, 0, sigreturn); /* li v0, sigreturn */
35 uasm_i_syscall(&tramp, 0);
36}
37
38static int __init init_vdso(void)
39{
40 struct mips_vdso *vdso;
41
42 vdso_page = alloc_page(GFP_KERNEL);
43 if (!vdso_page)
44 panic("Cannot allocate vdso");
45
46 vdso = vmap(&vdso_page, 1, 0, PAGE_KERNEL);
47 if (!vdso)
48 panic("Cannot map vdso");
49 clear_page(vdso);
50
51 install_trampoline(vdso->rt_signal_trampoline, __NR_rt_sigreturn);
52#ifdef CONFIG_32BIT
53 install_trampoline(vdso->signal_trampoline, __NR_sigreturn);
54#else
55 install_trampoline(vdso->n32_rt_signal_trampoline,
56 __NR_N32_rt_sigreturn);
57 install_trampoline(vdso->o32_signal_trampoline, __NR_O32_sigreturn);
58 install_trampoline(vdso->o32_rt_signal_trampoline,
59 __NR_O32_rt_sigreturn);
60#endif
61
62 vunmap(vdso);
63
64 return 0;
65}
66subsys_initcall(init_vdso);
67
68static unsigned long vdso_addr(unsigned long start)
69{
70 return STACK_TOP;
71}
72
73int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
74{
75 int ret;
76 unsigned long addr;
77 struct mm_struct *mm = current->mm;
78
79 down_write(&mm->mmap_sem);
80
81 addr = vdso_addr(mm->start_stack);
82
83 addr = get_unmapped_area(NULL, addr, PAGE_SIZE, 0, 0);
84 if (IS_ERR_VALUE(addr)) {
85 ret = addr;
86 goto up_fail;
87 }
88
89 ret = install_special_mapping(mm, addr, PAGE_SIZE,
90 VM_READ|VM_EXEC|
91 VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC|
92 VM_ALWAYSDUMP,
93 &vdso_page);
94
95 if (ret)
96 goto up_fail;
97
98 mm->context.vdso = (void *)addr;
99
100up_fail:
101 up_write(&mm->mmap_sem);
102 return ret;
103}
104
105const char *arch_vma_name(struct vm_area_struct *vma)
106{
107 if (vma->vm_mm && vma->vm_start == (long)vma->vm_mm->context.vdso)
108 return "[vdso]";
109 return NULL;
110}