1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Author: Huacai Chen <chenhuacai@loongson.cn> 4 * Copyright (C) 2020-2022 Loongson Technology Corporation Limited 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/page.h> 20 #include <asm/vdso.h> 21 #include <vdso/helpers.h> 22 #include <vdso/vsyscall.h> 23 #include <generated/vdso-offsets.h> 24 25 extern char vdso_start[], vdso_end[]; 26 27 /* Kernel-provided data used by the VDSO. */ 28 static union { 29 u8 page[VDSO_DATA_SIZE]; 30 struct loongarch_vdso_data vdata; 31 } loongarch_vdso_data __page_aligned_data; 32 33 static struct page *vdso_pages[] = { NULL }; 34 struct vdso_data *vdso_data = loongarch_vdso_data.vdata.data; 35 struct vdso_pcpu_data *vdso_pdata = loongarch_vdso_data.vdata.pdata; 36 37 static int vdso_mremap(const struct vm_special_mapping *sm, struct vm_area_struct *new_vma) 38 { 39 current->mm->context.vdso = (void *)(new_vma->vm_start); 40 41 return 0; 42 } 43 44 struct loongarch_vdso_info vdso_info = { 45 .vdso = vdso_start, 46 .size = PAGE_SIZE, 47 .code_mapping = { 48 .name = "[vdso]", 49 .pages = vdso_pages, 50 .mremap = vdso_mremap, 51 }, 52 .data_mapping = { 53 .name = "[vvar]", 54 }, 55 .offset_sigreturn = vdso_offset_sigreturn, 56 }; 57 58 static int __init init_vdso(void) 59 { 60 unsigned long i, cpu, pfn; 61 62 BUG_ON(!PAGE_ALIGNED(vdso_info.vdso)); 63 BUG_ON(!PAGE_ALIGNED(vdso_info.size)); 64 65 for_each_possible_cpu(cpu) 66 vdso_pdata[cpu].node = cpu_to_node(cpu); 67 68 pfn = __phys_to_pfn(__pa_symbol(vdso_info.vdso)); 69 for (i = 0; i < vdso_info.size / PAGE_SIZE; i++) 70 vdso_info.code_mapping.pages[i] = pfn_to_page(pfn + i); 71 72 return 0; 73 } 74 subsys_initcall(init_vdso); 75 76 static unsigned long vdso_base(void) 77 { 78 unsigned long base = STACK_TOP; 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 88 int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp) 89 { 90 int ret; 91 unsigned long vvar_size, size, data_addr, vdso_addr; 92 struct mm_struct *mm = current->mm; 93 struct vm_area_struct *vma; 94 struct loongarch_vdso_info *info = current->thread.vdso; 95 96 if (mmap_write_lock_killable(mm)) 97 return -EINTR; 98 99 /* 100 * Determine total area size. This includes the VDSO data itself 101 * and the data pages. 102 */ 103 vvar_size = VDSO_DATA_SIZE; 104 size = vvar_size + info->size; 105 106 data_addr = get_unmapped_area(NULL, vdso_base(), size, 0, 0); 107 if (IS_ERR_VALUE(data_addr)) { 108 ret = data_addr; 109 goto out; 110 } 111 vdso_addr = data_addr + VDSO_DATA_SIZE; 112 113 vma = _install_special_mapping(mm, data_addr, vvar_size, 114 VM_READ | VM_MAYREAD, 115 &info->data_mapping); 116 if (IS_ERR(vma)) { 117 ret = PTR_ERR(vma); 118 goto out; 119 } 120 121 /* Map VDSO data page. */ 122 ret = remap_pfn_range(vma, data_addr, 123 virt_to_phys(&loongarch_vdso_data) >> PAGE_SHIFT, 124 vvar_size, PAGE_READONLY); 125 if (ret) 126 goto out; 127 128 /* Map VDSO code page. */ 129 vma = _install_special_mapping(mm, vdso_addr, info->size, 130 VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC, 131 &info->code_mapping); 132 if (IS_ERR(vma)) { 133 ret = PTR_ERR(vma); 134 goto out; 135 } 136 137 mm->context.vdso = (void *)vdso_addr; 138 ret = 0; 139 140 out: 141 mmap_write_unlock(mm); 142 return ret; 143 } 144