1 /* 2 * Copyright (C) 2015 Imagination Technologies 3 * Author: Alex Smith <alex.smith@imgtec.com> 4 * 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. 9 */ 10 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/irqchip/mips-gic.h> 17 #include <linux/mm.h> 18 #include <linux/sched.h> 19 #include <linux/slab.h> 20 #include <linux/timekeeper_internal.h> 21 22 #include <asm/abi.h> 23 #include <asm/vdso.h> 24 25 /* Kernel-provided data used by the VDSO. */ 26 static union mips_vdso_data vdso_data __page_aligned_data; 27 28 /* 29 * Mapping for the VDSO data/GIC pages. The real pages are mapped manually, as 30 * what we map and where within the area they are mapped is determined at 31 * runtime. 32 */ 33 static struct page *no_pages[] = { NULL }; 34 static struct vm_special_mapping vdso_vvar_mapping = { 35 .name = "[vvar]", 36 .pages = no_pages, 37 }; 38 39 static void __init init_vdso_image(struct mips_vdso_image *image) 40 { 41 unsigned long num_pages, i; 42 unsigned long data_pfn; 43 44 BUG_ON(!PAGE_ALIGNED(image->data)); 45 BUG_ON(!PAGE_ALIGNED(image->size)); 46 47 num_pages = image->size / PAGE_SIZE; 48 49 data_pfn = __phys_to_pfn(__pa_symbol(image->data)); 50 for (i = 0; i < num_pages; i++) 51 image->mapping.pages[i] = pfn_to_page(data_pfn + i); 52 } 53 54 static int __init init_vdso(void) 55 { 56 init_vdso_image(&vdso_image); 57 58 #ifdef CONFIG_MIPS32_O32 59 init_vdso_image(&vdso_image_o32); 60 #endif 61 62 #ifdef CONFIG_MIPS32_N32 63 init_vdso_image(&vdso_image_n32); 64 #endif 65 66 return 0; 67 } 68 subsys_initcall(init_vdso); 69 70 void update_vsyscall(struct timekeeper *tk) 71 { 72 vdso_data_write_begin(&vdso_data); 73 74 vdso_data.xtime_sec = tk->xtime_sec; 75 vdso_data.xtime_nsec = tk->tkr_mono.xtime_nsec; 76 vdso_data.wall_to_mono_sec = tk->wall_to_monotonic.tv_sec; 77 vdso_data.wall_to_mono_nsec = tk->wall_to_monotonic.tv_nsec; 78 vdso_data.cs_shift = tk->tkr_mono.shift; 79 80 vdso_data.clock_mode = tk->tkr_mono.clock->archdata.vdso_clock_mode; 81 if (vdso_data.clock_mode != VDSO_CLOCK_NONE) { 82 vdso_data.cs_mult = tk->tkr_mono.mult; 83 vdso_data.cs_cycle_last = tk->tkr_mono.cycle_last; 84 vdso_data.cs_mask = tk->tkr_mono.mask; 85 } 86 87 vdso_data_write_end(&vdso_data); 88 } 89 90 void update_vsyscall_tz(void) 91 { 92 if (vdso_data.clock_mode != VDSO_CLOCK_NONE) { 93 vdso_data.tz_minuteswest = sys_tz.tz_minuteswest; 94 vdso_data.tz_dsttime = sys_tz.tz_dsttime; 95 } 96 } 97 98 int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp) 99 { 100 struct mips_vdso_image *image = current->thread.abi->vdso; 101 struct mm_struct *mm = current->mm; 102 unsigned long gic_size, vvar_size, size, base, data_addr, vdso_addr; 103 struct vm_area_struct *vma; 104 struct resource gic_res; 105 int ret; 106 107 if (down_write_killable(&mm->mmap_sem)) 108 return -EINTR; 109 110 /* Map delay slot emulation page */ 111 base = mmap_region(NULL, STACK_TOP, PAGE_SIZE, 112 VM_READ|VM_WRITE|VM_EXEC| 113 VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC, 114 0); 115 if (IS_ERR_VALUE(base)) { 116 ret = base; 117 goto out; 118 } 119 120 /* 121 * Determine total area size. This includes the VDSO data itself, the 122 * data page, and the GIC user page if present. Always create a mapping 123 * for the GIC user area if the GIC is present regardless of whether it 124 * is the current clocksource, in case it comes into use later on. We 125 * only map a page even though the total area is 64K, as we only need 126 * the counter registers at the start. 127 */ 128 gic_size = gic_present ? PAGE_SIZE : 0; 129 vvar_size = gic_size + PAGE_SIZE; 130 size = vvar_size + image->size; 131 132 base = get_unmapped_area(NULL, 0, size, 0, 0); 133 if (IS_ERR_VALUE(base)) { 134 ret = base; 135 goto out; 136 } 137 138 data_addr = base + gic_size; 139 vdso_addr = data_addr + PAGE_SIZE; 140 141 vma = _install_special_mapping(mm, base, vvar_size, 142 VM_READ | VM_MAYREAD, 143 &vdso_vvar_mapping); 144 if (IS_ERR(vma)) { 145 ret = PTR_ERR(vma); 146 goto out; 147 } 148 149 /* Map GIC user page. */ 150 if (gic_size) { 151 ret = gic_get_usm_range(&gic_res); 152 if (ret) 153 goto out; 154 155 ret = io_remap_pfn_range(vma, base, 156 gic_res.start >> PAGE_SHIFT, 157 gic_size, 158 pgprot_noncached(PAGE_READONLY)); 159 if (ret) 160 goto out; 161 } 162 163 /* Map data page. */ 164 ret = remap_pfn_range(vma, data_addr, 165 virt_to_phys(&vdso_data) >> PAGE_SHIFT, 166 PAGE_SIZE, PAGE_READONLY); 167 if (ret) 168 goto out; 169 170 /* Map VDSO image. */ 171 vma = _install_special_mapping(mm, vdso_addr, image->size, 172 VM_READ | VM_EXEC | 173 VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC, 174 &image->mapping); 175 if (IS_ERR(vma)) { 176 ret = PTR_ERR(vma); 177 goto out; 178 } 179 180 mm->context.vdso = (void *)vdso_addr; 181 ret = 0; 182 183 out: 184 up_write(&mm->mmap_sem); 185 return ret; 186 } 187