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