1 // SPDX-License-Identifier: GPL-2.0 2 // Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd. 3 4 #include <linux/binfmts.h> 5 #include <linux/elf.h> 6 #include <linux/err.h> 7 #include <linux/mm.h> 8 #include <linux/slab.h> 9 10 #include <asm/page.h> 11 #ifdef GENERIC_TIME_VSYSCALL 12 #include <vdso/datapage.h> 13 #else 14 #include <asm/vdso.h> 15 #endif 16 17 extern char vdso_start[], vdso_end[]; 18 19 static unsigned int vdso_pages; 20 static struct page **vdso_pagelist; 21 22 /* 23 * The vDSO data page. 24 */ 25 static union { 26 struct vdso_data data; 27 u8 page[PAGE_SIZE]; 28 } vdso_data_store __page_aligned_data; 29 struct vdso_data *vdso_data = &vdso_data_store.data; 30 31 static int __init vdso_init(void) 32 { 33 unsigned int i; 34 35 vdso_pages = (vdso_end - vdso_start) >> PAGE_SHIFT; 36 vdso_pagelist = 37 kcalloc(vdso_pages + 1, sizeof(struct page *), GFP_KERNEL); 38 if (unlikely(vdso_pagelist == NULL)) { 39 pr_err("vdso: pagelist allocation failed\n"); 40 return -ENOMEM; 41 } 42 43 for (i = 0; i < vdso_pages; i++) { 44 struct page *pg; 45 46 pg = virt_to_page(vdso_start + (i << PAGE_SHIFT)); 47 vdso_pagelist[i] = pg; 48 } 49 vdso_pagelist[i] = virt_to_page(vdso_data); 50 51 return 0; 52 } 53 arch_initcall(vdso_init); 54 55 int arch_setup_additional_pages(struct linux_binprm *bprm, 56 int uses_interp) 57 { 58 struct mm_struct *mm = current->mm; 59 unsigned long vdso_base, vdso_len; 60 int ret; 61 62 vdso_len = (vdso_pages + 1) << PAGE_SHIFT; 63 64 mmap_write_lock(mm); 65 vdso_base = get_unmapped_area(NULL, 0, vdso_len, 0, 0); 66 if (IS_ERR_VALUE(vdso_base)) { 67 ret = vdso_base; 68 goto end; 69 } 70 71 /* 72 * Put vDSO base into mm struct. We need to do this before calling 73 * install_special_mapping or the perf counter mmap tracking code 74 * will fail to recognise it as a vDSO (since arch_vma_name fails). 75 */ 76 mm->context.vdso = (void *)vdso_base; 77 78 ret = 79 install_special_mapping(mm, vdso_base, vdso_pages << PAGE_SHIFT, 80 (VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC), 81 vdso_pagelist); 82 83 if (unlikely(ret)) { 84 mm->context.vdso = NULL; 85 goto end; 86 } 87 88 vdso_base += (vdso_pages << PAGE_SHIFT); 89 ret = install_special_mapping(mm, vdso_base, PAGE_SIZE, 90 (VM_READ | VM_MAYREAD), &vdso_pagelist[vdso_pages]); 91 92 if (unlikely(ret)) 93 mm->context.vdso = NULL; 94 end: 95 mmap_write_unlock(mm); 96 return ret; 97 } 98 99 const char *arch_vma_name(struct vm_area_struct *vma) 100 { 101 if (vma->vm_mm && (vma->vm_start == (long)vma->vm_mm->context.vdso)) 102 return "[vdso]"; 103 if (vma->vm_mm && (vma->vm_start == 104 (long)vma->vm_mm->context.vdso + PAGE_SIZE)) 105 return "[vdso_data]"; 106 return NULL; 107 } 108