124 lines
3.0 KiB
C
124 lines
3.0 KiB
C
/*
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* Copyright (c) 2014, The Linux Foundation. All rights reserved.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 and
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* only version 2 as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*/
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#include <linux/kernel.h>
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#include <linux/mm.h>
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#include <linux/sched.h>
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#include <asm/pgtable.h>
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#include <asm/tlbflush.h>
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static pte_t clear_pte_bit(pte_t pte, pgprot_t prot)
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{
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pte_val(pte) &= ~pgprot_val(prot);
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return pte;
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}
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static pte_t set_pte_bit(pte_t pte, pgprot_t prot)
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{
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pte_val(pte) |= pgprot_val(prot);
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return pte;
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}
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static int __change_memory(pte_t *ptep, pgtable_t token, unsigned long addr,
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pgprot_t prot, bool set)
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{
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pte_t pte;
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if (set)
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pte = set_pte_bit(*ptep, prot);
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else
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pte = clear_pte_bit(*ptep, prot);
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set_pte(ptep, pte);
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return 0;
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}
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static int set_page_range(pte_t *ptep, pgtable_t token, unsigned long addr,
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void *data)
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{
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pgprot_t prot = (pgprot_t)data;
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return __change_memory(ptep, token, addr, prot, true);
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}
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static int clear_page_range(pte_t *ptep, pgtable_t token, unsigned long addr,
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void *data)
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{
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pgprot_t prot = (pgprot_t)data;
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return __change_memory(ptep, token, addr, prot, false);
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}
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static int change_memory_common(unsigned long addr, int numpages,
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pgprot_t prot, bool set)
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{
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unsigned long start = addr;
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unsigned long size = PAGE_SIZE*numpages;
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unsigned long end = start + size;
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int ret;
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if (!IS_ENABLED(CONFIG_FORCE_PAGES)) {
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if (start < MODULES_VADDR || start >= MODULES_END)
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return -EINVAL;
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if (end < MODULES_VADDR || end >= MODULES_END)
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return -EINVAL;
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}
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if (set)
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ret = apply_to_page_range(&init_mm, start, size,
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set_page_range, (void *)prot);
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else
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ret = apply_to_page_range(&init_mm, start, size,
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clear_page_range, (void *)prot);
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flush_tlb_kernel_range(start, end);
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isb();
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return ret;
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}
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static int change_memory_set_bit(unsigned long addr, int numpages,
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pgprot_t prot)
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{
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return change_memory_common(addr, numpages, prot, true);
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}
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static int change_memory_clear_bit(unsigned long addr, int numpages,
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pgprot_t prot)
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{
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return change_memory_common(addr, numpages, prot, false);
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}
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int set_memory_ro(unsigned long addr, int numpages)
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{
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return change_memory_set_bit(addr, numpages, __pgprot(PTE_RDONLY));
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}
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EXPORT_SYMBOL(set_memory_ro);
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int set_memory_rw(unsigned long addr, int numpages)
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{
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return change_memory_clear_bit(addr, numpages, __pgprot(PTE_RDONLY));
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}
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EXPORT_SYMBOL(set_memory_rw);
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int set_memory_nx(unsigned long addr, int numpages)
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{
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return change_memory_set_bit(addr, numpages, __pgprot(PTE_PXN));
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}
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EXPORT_SYMBOL(set_memory_nx);
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int set_memory_x(unsigned long addr, int numpages)
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{
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return change_memory_clear_bit(addr, numpages, __pgprot(PTE_PXN));
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}
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EXPORT_SYMBOL(set_memory_x);
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