2 * Copyright (C) 2015 Imagination Technologies
3 * Author: Alex Smith <alex.smith@imgtec.com>
5 * This program is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License as published by the
7 * Free Software Foundation; either version 2 of the License, or (at your
8 * option) any later version.
11 #include <linux/binfmts.h>
12 #include <linux/elf.h>
13 #include <linux/err.h>
14 #include <linux/init.h>
15 #include <linux/ioport.h>
16 #include <linux/kernel.h>
18 #include <linux/sched.h>
19 #include <linux/slab.h>
20 #include <linux/timekeeper_internal.h>
23 #include <asm/mips-cps.h>
27 /* Kernel-provided data used by the VDSO. */
28 static union mips_vdso_data vdso_data __page_aligned_data;
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
35 static struct page *no_pages[] = { NULL };
36 static struct vm_special_mapping vdso_vvar_mapping = {
41 static void __init init_vdso_image(struct mips_vdso_image *image)
43 unsigned long num_pages, i;
44 unsigned long data_pfn;
46 BUG_ON(!PAGE_ALIGNED(image->data));
47 BUG_ON(!PAGE_ALIGNED(image->size));
49 num_pages = image->size / PAGE_SIZE;
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);
56 static int __init init_vdso(void)
58 init_vdso_image(&vdso_image);
60 #ifdef CONFIG_MIPS32_O32
61 init_vdso_image(&vdso_image_o32);
64 #ifdef CONFIG_MIPS32_N32
65 init_vdso_image(&vdso_image_n32);
70 subsys_initcall(init_vdso);
72 void update_vsyscall(struct timekeeper *tk)
74 vdso_data_write_begin(&vdso_data);
76 vdso_data.xtime_sec = tk->xtime_sec;
77 vdso_data.xtime_nsec = tk->tkr_mono.xtime_nsec;
78 vdso_data.wall_to_mono_sec = tk->wall_to_monotonic.tv_sec;
79 vdso_data.wall_to_mono_nsec = tk->wall_to_monotonic.tv_nsec;
80 vdso_data.cs_shift = tk->tkr_mono.shift;
82 vdso_data.clock_mode = tk->tkr_mono.clock->archdata.vdso_clock_mode;
83 if (vdso_data.clock_mode != VDSO_CLOCK_NONE) {
84 vdso_data.cs_mult = tk->tkr_mono.mult;
85 vdso_data.cs_cycle_last = tk->tkr_mono.cycle_last;
86 vdso_data.cs_mask = tk->tkr_mono.mask;
89 vdso_data_write_end(&vdso_data);
92 void update_vsyscall_tz(void)
94 if (vdso_data.clock_mode != VDSO_CLOCK_NONE) {
95 vdso_data.tz_minuteswest = sys_tz.tz_minuteswest;
96 vdso_data.tz_dsttime = sys_tz.tz_dsttime;
100 int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
102 struct mips_vdso_image *image = current->thread.abi->vdso;
103 struct mm_struct *mm = current->mm;
104 unsigned long gic_size, vvar_size, size, base, data_addr, vdso_addr, gic_pfn;
105 struct vm_area_struct *vma;
108 if (down_write_killable(&mm->mmap_sem))
111 /* Map delay slot emulation page */
112 base = mmap_region(NULL, STACK_TOP, PAGE_SIZE,
113 VM_READ|VM_WRITE|VM_EXEC|
114 VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC,
116 if (IS_ERR_VALUE(base)) {
122 * Determine total area size. This includes the VDSO data itself, the
123 * data page, and the GIC user page if present. Always create a mapping
124 * for the GIC user area if the GIC is present regardless of whether it
125 * is the current clocksource, in case it comes into use later on. We
126 * only map a page even though the total area is 64K, as we only need
127 * the counter registers at the start.
129 gic_size = mips_gic_present() ? PAGE_SIZE : 0;
130 vvar_size = gic_size + PAGE_SIZE;
131 size = vvar_size + image->size;
134 * Find a region that's large enough for us to perform the
135 * colour-matching alignment below.
137 if (cpu_has_dc_aliases)
138 size += shm_align_mask + 1;
140 base = get_unmapped_area(NULL, 0, size, 0, 0);
141 if (IS_ERR_VALUE(base)) {
147 * If we suffer from dcache aliasing, ensure that the VDSO data page
148 * mapping is coloured the same as the kernel's mapping of that memory.
149 * This ensures that when the kernel updates the VDSO data userland
150 * will observe it without requiring cache invalidations.
152 if (cpu_has_dc_aliases) {
153 base = __ALIGN_MASK(base, shm_align_mask);
154 base += ((unsigned long)&vdso_data - gic_size) & shm_align_mask;
157 data_addr = base + gic_size;
158 vdso_addr = data_addr + PAGE_SIZE;
160 vma = _install_special_mapping(mm, base, vvar_size,
161 VM_READ | VM_MAYREAD,
168 /* Map GIC user page. */
170 gic_pfn = virt_to_phys(mips_gic_base + MIPS_GIC_USER_OFS) >> PAGE_SHIFT;
172 ret = io_remap_pfn_range(vma, base, gic_pfn, gic_size,
173 pgprot_noncached(PAGE_READONLY));
179 ret = remap_pfn_range(vma, data_addr,
180 virt_to_phys(&vdso_data) >> PAGE_SHIFT,
181 PAGE_SIZE, PAGE_READONLY);
185 /* Map VDSO image. */
186 vma = _install_special_mapping(mm, vdso_addr, image->size,
188 VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC,
195 mm->context.vdso = (void *)vdso_addr;
199 up_write(&mm->mmap_sem);