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Arnd Bergmann
6b76ca2ab9
The devmem_is_allowed() function is defined in a file of the same name, but the declaration is in asm/io.h, which is not included there, causing a W=1 warning: lib/devmem_is_allowed.c:20:5: error: no previous prototype for 'devmem_is_allowed' [-Werror=missing-prototypes] Include the appropriate header to avoid the warning. Link: https://lkml.kernel.org/r/[email protected] Signed-off-by: Arnd Bergmann <[email protected]> Cc: Boqun Feng <[email protected]> Cc: Catalin Marinas <[email protected]> Cc: Christoph Lameter <[email protected]> Cc: Dennis Zhou <[email protected]> Cc: Eric Paris <[email protected]> Cc: Heiko Carstens <[email protected]> Cc: Helge Deller <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: Michael Ellerman <[email protected]> Cc: Michal Simek <[email protected]> Cc: Palmer Dabbelt <[email protected]> Cc: Paul Moore <[email protected]> Cc: Pavel Machek <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Rafael J. Wysocki <[email protected]> Cc: Russell King <[email protected]> Cc: Tejun Heo <[email protected]> Cc: Thomas Bogendoerfer <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: Waiman Long <[email protected]> Cc: Will Deacon <[email protected]> Signed-off-by: Andrew Morton <[email protected]>
29 lines
705 B
C
29 lines
705 B
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* A generic version of devmem_is_allowed.
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*
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* Based on arch/arm64/mm/mmap.c
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*
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* Copyright (C) 2020 Google, Inc.
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* Copyright (C) 2012 ARM Ltd.
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*/
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#include <linux/mm.h>
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#include <linux/ioport.h>
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#include <linux/io.h>
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/*
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* devmem_is_allowed() checks to see if /dev/mem access to a certain address
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* is valid. The argument is a physical page number. We mimic x86 here by
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* disallowing access to system RAM as well as device-exclusive MMIO regions.
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* This effectively disable read()/write() on /dev/mem.
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*/
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int devmem_is_allowed(unsigned long pfn)
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{
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if (iomem_is_exclusive(PFN_PHYS(pfn)))
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return 0;
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if (!page_is_ram(pfn))
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return 1;
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return 0;
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}
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