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/vdso_datastore.h> 18 19 #include <asm/page.h> 20 #include <asm/vdso.h> 21 #include <asm/vdso/vdso.h> 22 #include <vdso/helpers.h> 23 #include <vdso/vsyscall.h> 24 #include <vdso/datapage.h> 25 #include <generated/vdso-offsets.h> 26 27 extern char vdso_start[], vdso_end[]; 28 29 static int vdso_mremap(const struct vm_special_mapping *sm, struct vm_area_struct *new_vma) 30 { 31 current->mm->context.vdso = (void *)(new_vma->vm_start); 32 33 return 0; 34 } 35 36 struct loongarch_vdso_info vdso_info = { 37 .vdso = vdso_start, 38 .code_mapping = { 39 .name = "[vdso]", 40 .mremap = vdso_mremap, 41 }, 42 .offset_sigreturn = vdso_offset_sigreturn, 43 }; 44 45 static int __init init_vdso(void) 46 { 47 unsigned long i, cpu, pfn; 48 49 BUG_ON(!PAGE_ALIGNED(vdso_info.vdso)); 50 51 for_each_possible_cpu(cpu) 52 vdso_k_arch_data->pdata[cpu].node = cpu_to_node(cpu); 53 54 vdso_info.size = PAGE_ALIGN(vdso_end - vdso_start); 55 vdso_info.code_mapping.pages = 56 kzalloc_objs(struct page *, vdso_info.size / PAGE_SIZE); 57 58 if (!vdso_info.code_mapping.pages) 59 return -ENOMEM; 60 61 pfn = __phys_to_pfn(__pa_symbol(vdso_info.vdso)); 62 for (i = 0; i < vdso_info.size / PAGE_SIZE; i++) 63 vdso_info.code_mapping.pages[i] = pfn_to_page(pfn + i); 64 65 return 0; 66 } 67 subsys_initcall(init_vdso); 68 69 static unsigned long vdso_base(void) 70 { 71 unsigned long base = STACK_TOP; 72 73 if (current->flags & PF_RANDOMIZE) { 74 base += get_random_u32_below(VDSO_RANDOMIZE_SIZE); 75 base = PAGE_ALIGN(base); 76 } 77 78 return base; 79 } 80 81 int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp) 82 { 83 int ret; 84 unsigned long size, data_addr, vdso_addr; 85 struct mm_struct *mm = current->mm; 86 struct vm_area_struct *vma; 87 struct loongarch_vdso_info *info = current->thread.vdso; 88 89 if (mmap_write_lock_killable(mm)) 90 return -EINTR; 91 92 /* 93 * Determine total area size. This includes the VDSO data itself 94 * and the data pages. 95 */ 96 size = VVAR_SIZE + info->size; 97 98 data_addr = get_unmapped_area(NULL, vdso_base(), size, 0, 0); 99 if (IS_ERR_VALUE(data_addr)) { 100 ret = data_addr; 101 goto out; 102 } 103 104 vma = vdso_install_vvar_mapping(mm, data_addr); 105 if (IS_ERR(vma)) { 106 ret = PTR_ERR(vma); 107 goto out; 108 } 109 110 vdso_addr = data_addr + VVAR_SIZE; 111 vma = _install_special_mapping(mm, vdso_addr, info->size, 112 VM_READ | VM_EXEC | 113 VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC | 114 VM_SEALED_SYSMAP, 115 &info->code_mapping); 116 if (IS_ERR(vma)) { 117 ret = PTR_ERR(vma); 118 goto out; 119 } 120 121 mm->context.vdso = (void *)vdso_addr; 122 ret = 0; 123 124 out: 125 mmap_write_unlock(mm); 126 return ret; 127 } 128