blob: 3028bacbc4e9c40135b1f84a28a67500218c3078 [file] [log] [blame]
// SPDX-License-Identifier: GPL-2.0-only
* Based on arch/arm/mm/mmap.c
* Copyright (C) 2012 ARM Ltd.
#include <linux/elf.h>
#include <linux/fs.h>
#include <linux/memblock.h>
#include <linux/mm.h>
#include <linux/mman.h>
#include <linux/export.h>
#include <linux/shm.h>
#include <linux/sched/signal.h>
#include <linux/sched/mm.h>
#include <linux/io.h>
#include <linux/personality.h>
#include <linux/random.h>
#include <asm/cputype.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) &&
* 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);
#include <linux/ioport.h>
* devmem_is_allowed() checks to see if /dev/mem access to a certain address
* is valid. The argument is a physical page number. We mimic x86 here by
* disallowing access to system RAM as well as device-exclusive MMIO regions.
* This effectively disable read()/write() on /dev/mem.
int devmem_is_allowed(unsigned long pfn)
if (iomem_is_exclusive(pfn << PAGE_SHIFT))
return 0;
if (!page_is_ram(pfn))
return 1;
return 0;