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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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1234567891011121314151617181920212223242526272829// SPDX-License-Identifier: GPL-2.0-only/* * A generic version of devmem_is_allowed. * * Based on arch/arm64/mm/mmap.c * * Copyright (C) 2020 Google, Inc. * Copyright (C) 2012 ARM Ltd. */
#include <linux/mm.h>#include <linux/ioport.h>#include <linux/io.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_PHYS(pfn))) return 0; if (!page_is_ram(pfn)) return 1; return 0;}