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
 17extern char vdso_start[], vdso_end[];
 18
 19static unsigned int vdso_pages;
 20static struct page **vdso_pagelist;
 21
 22/*
 23 * The vDSO data page.
 24 */
 25static union {
 26	struct vdso_data	data;
 27	u8			page[PAGE_SIZE];
 28} vdso_data_store __page_aligned_data;
 29struct vdso_data *vdso_data = &vdso_data_store.data;
 30
 31static 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}
 53arch_initcall(vdso_init);
 54
 55int 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;
 94end:
 95	mmap_write_unlock(mm);
 96	return ret;
 97}
 98
 99const 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}