58 lines
1.5 KiB
C
58 lines
1.5 KiB
C
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// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Based on arch/arm/mm/mmap.c
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*
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* Copyright (C) 2012 ARM Ltd.
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*/
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#include <linux/io.h>
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#include <linux/memblock.h>
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#include <linux/mm.h>
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#include <linux/types.h>
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#include <asm/cpufeature.h>
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#include <asm/page.h>
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/*
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* You really shouldn't be using read() or write() on /dev/mem. This might go
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* away in the future.
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*/
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int valid_phys_addr_range(phys_addr_t addr, size_t size)
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{
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/*
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* Check whether addr is covered by a memory region without the
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* MEMBLOCK_NOMAP attribute, and whether that region covers the
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* entire range. In theory, this could lead to false negatives
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* if the range is covered by distinct but adjacent memory regions
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* that only differ in other attributes. However, few of such
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* attributes have been defined, and it is debatable whether it
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* follows that /dev/mem read() calls should be able traverse
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* such boundaries.
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*/
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return memblock_is_region_memory(addr, size) &&
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memblock_is_map_memory(addr);
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}
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/*
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* Do not allow /dev/mem mappings beyond the supported physical range.
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*/
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int valid_mmap_phys_addr_range(unsigned long pfn, size_t size)
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{
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return !(((pfn << PAGE_SHIFT) + size) & ~PHYS_MASK);
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}
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static int __init adjust_protection_map(void)
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{
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/*
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* With Enhanced PAN we can honour the execute-only permissions as
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* there is no PAN override with such mappings.
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*/
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if (cpus_have_const_cap(ARM64_HAS_EPAN)) {
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protection_map[VM_EXEC] = PAGE_EXECONLY;
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protection_map[VM_EXEC | VM_SHARED] = PAGE_EXECONLY;
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}
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return 0;
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}
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arch_initcall(adjust_protection_map);
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