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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pageattr.c (2638B)

      1// SPDX-License-Identifier: GPL-2.0-only
      2/*
      3 * Copyright (c) 2014, The Linux Foundation. All rights reserved.
      4 */
      5#include <linux/mm.h>
      6#include <linux/module.h>
      7
      8#include <asm/tlbflush.h>
      9#include <asm/set_memory.h>
     10
     11struct page_change_data {
     12	pgprot_t set_mask;
     13	pgprot_t clear_mask;
     14};
     15
     16static int change_page_range(pte_t *ptep, unsigned long addr, void *data)
     17{
     18	struct page_change_data *cdata = data;
     19	pte_t pte = *ptep;
     20
     21	pte = clear_pte_bit(pte, cdata->clear_mask);
     22	pte = set_pte_bit(pte, cdata->set_mask);
     23
     24	set_pte_ext(ptep, pte, 0);
     25	return 0;
     26}
     27
     28static bool in_range(unsigned long start, unsigned long size,
     29	unsigned long range_start, unsigned long range_end)
     30{
     31	return start >= range_start && start < range_end &&
     32		size <= range_end - start;
     33}
     34
     35/*
     36 * This function assumes that the range is mapped with PAGE_SIZE pages.
     37 */
     38static int __change_memory_common(unsigned long start, unsigned long size,
     39				pgprot_t set_mask, pgprot_t clear_mask)
     40{
     41	struct page_change_data data;
     42	int ret;
     43
     44	data.set_mask = set_mask;
     45	data.clear_mask = clear_mask;
     46
     47	ret = apply_to_page_range(&init_mm, start, size, change_page_range,
     48				  &data);
     49
     50	flush_tlb_kernel_range(start, start + size);
     51	return ret;
     52}
     53
     54static int change_memory_common(unsigned long addr, int numpages,
     55				pgprot_t set_mask, pgprot_t clear_mask)
     56{
     57	unsigned long start = addr & PAGE_MASK;
     58	unsigned long end = PAGE_ALIGN(addr) + numpages * PAGE_SIZE;
     59	unsigned long size = end - start;
     60
     61	WARN_ON_ONCE(start != addr);
     62
     63	if (!size)
     64		return 0;
     65
     66	if (!in_range(start, size, MODULES_VADDR, MODULES_END) &&
     67	    !in_range(start, size, VMALLOC_START, VMALLOC_END))
     68		return -EINVAL;
     69
     70	return __change_memory_common(start, size, set_mask, clear_mask);
     71}
     72
     73int set_memory_ro(unsigned long addr, int numpages)
     74{
     75	return change_memory_common(addr, numpages,
     76					__pgprot(L_PTE_RDONLY),
     77					__pgprot(0));
     78}
     79
     80int set_memory_rw(unsigned long addr, int numpages)
     81{
     82	return change_memory_common(addr, numpages,
     83					__pgprot(0),
     84					__pgprot(L_PTE_RDONLY));
     85}
     86
     87int set_memory_nx(unsigned long addr, int numpages)
     88{
     89	return change_memory_common(addr, numpages,
     90					__pgprot(L_PTE_XN),
     91					__pgprot(0));
     92}
     93
     94int set_memory_x(unsigned long addr, int numpages)
     95{
     96	return change_memory_common(addr, numpages,
     97					__pgprot(0),
     98					__pgprot(L_PTE_XN));
     99}
    100
    101int set_memory_valid(unsigned long addr, int numpages, int enable)
    102{
    103	if (enable)
    104		return __change_memory_common(addr, PAGE_SIZE * numpages,
    105					      __pgprot(L_PTE_VALID),
    106					      __pgprot(0));
    107	else
    108		return __change_memory_common(addr, PAGE_SIZE * numpages,
    109					      __pgprot(0),
    110					      __pgprot(L_PTE_VALID));
    111}