71 lines
1.8 KiB
C
71 lines
1.8 KiB
C
// 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) &&
|
|
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);
|
|
}
|
|
|
|
#ifdef CONFIG_STRICT_DEVMEM
|
|
|
|
#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;
|
|
}
|
|
|
|
#endif
|