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/*
* Copyright (c) 2014, The Linux Foundation. All rights reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 and
* only version 2 as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#include <linux/mm.h>
#include <linux/module.h>
#include <asm/pgtable.h>
#include <asm/tlbflush.h>
#include <asm/set_memory.h>
struct page_change_data {
pgprot_t set_mask;
pgprot_t clear_mask;
};
static int change_page_range(pte_t *ptep, pgtable_t token, unsigned long addr,
void *data)
{
struct page_change_data *cdata = data;
pte_t pte = *ptep;
pte = clear_pte_bit(pte, cdata->clear_mask);
pte = set_pte_bit(pte, cdata->set_mask);
set_pte_ext(ptep, pte, 0);
return 0;
}
static bool in_range(unsigned long start, unsigned long size,
unsigned long range_start, unsigned long range_end)
{
return start >= range_start && start < range_end &&
size <= range_end - start;
}
static int change_memory_common(unsigned long addr, int numpages,
pgprot_t set_mask, pgprot_t clear_mask)
{
unsigned long start = addr & PAGE_MASK;
unsigned long end = PAGE_ALIGN(addr) + numpages * PAGE_SIZE;
unsigned long size = end - start;
int ret;
struct page_change_data data;
WARN_ON_ONCE(start != addr);
if (!size)
return 0;
if (!in_range(start, size, MODULES_VADDR, MODULES_END) &&
!in_range(start, size, VMALLOC_START, VMALLOC_END))
return -EINVAL;
data.set_mask = set_mask;
data.clear_mask = clear_mask;
ret = apply_to_page_range(&init_mm, start, size, change_page_range,
&data);
flush_tlb_kernel_range(start, end);
return ret;
}
int set_memory_ro(unsigned long addr, int numpages)
{
return change_memory_common(addr, numpages,
__pgprot(L_PTE_RDONLY),
__pgprot(0));
}
int set_memory_rw(unsigned long addr, int numpages)
{
return change_memory_common(addr, numpages,
__pgprot(0),
__pgprot(L_PTE_RDONLY));
}
int set_memory_nx(unsigned long addr, int numpages)
{
return change_memory_common(addr, numpages,
__pgprot(L_PTE_XN),
__pgprot(0));
}
int set_memory_x(unsigned long addr, int numpages)
{
return change_memory_common(addr, numpages,
__pgprot(0),
__pgprot(L_PTE_XN));
}
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