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