cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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vdso.c (2492B)

      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}