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