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torvalds
GitHub Repository: torvalds/linux
 Path: blob/master/arch/arc/mm/mmap.c
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// SPDX-License-Identifier: GPL-2.0-only

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/*

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 * ARC700 mmap

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 *

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 * (started from arm version - for VIPT alias handling)

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 *

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 * Copyright (C) 2013 Synopsys, Inc. (www.synopsys.com)

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 */

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#include <linux/fs.h>

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#include <linux/mm.h>

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#include <linux/mman.h>

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#include <linux/sched/mm.h>

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#include <asm/cacheflush.h>

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/*

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 * Ensure that shared mappings are correctly aligned to

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 * avoid aliasing issues with VIPT caches.

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 * We need to ensure that

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 * a specific page of an object is always mapped at a multiple of

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 * SHMLBA bytes.

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 */

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unsigned long

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arch_get_unmapped_area(struct file *filp, unsigned long addr,

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		unsigned long len, unsigned long pgoff,

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		unsigned long flags, vm_flags_t vm_flags)

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{

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	struct mm_struct *mm = current->mm;

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	struct vm_area_struct *vma;

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	struct vm_unmapped_area_info info = {};

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	/*

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	 * We enforce the MAP_FIXED case.

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	 */

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	if (flags & MAP_FIXED) {

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		if (flags & MAP_SHARED &&

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		    (addr - (pgoff << PAGE_SHIFT)) & (SHMLBA - 1))

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			return -EINVAL;

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		return addr;

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	}

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	if (len > TASK_SIZE)

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		return -ENOMEM;

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	if (addr) {

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		addr = PAGE_ALIGN(addr);

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		vma = find_vma(mm, addr);

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		if (TASK_SIZE - len >= addr &&

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		    (!vma || addr + len <= vm_start_gap(vma)))

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			return addr;

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	}

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	info.length = len;

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	info.low_limit = mm->mmap_base;

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	info.high_limit = TASK_SIZE;

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	info.align_offset = pgoff << PAGE_SHIFT;

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	return vm_unmapped_area(&info);

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}

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static const pgprot_t protection_map[16] = {

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	[VM_NONE]					= PAGE_U_NONE,

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	[VM_READ]					= PAGE_U_R,

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	[VM_WRITE]					= PAGE_U_R,

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	[VM_WRITE | VM_READ]				= PAGE_U_R,

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	[VM_EXEC]					= PAGE_U_X_R,

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	[VM_EXEC | VM_READ]				= PAGE_U_X_R,

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	[VM_EXEC | VM_WRITE]				= PAGE_U_X_R,

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	[VM_EXEC | VM_WRITE | VM_READ]			= PAGE_U_X_R,

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	[VM_SHARED]					= PAGE_U_NONE,

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	[VM_SHARED | VM_READ]				= PAGE_U_R,

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	[VM_SHARED | VM_WRITE]				= PAGE_U_W_R,

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	[VM_SHARED | VM_WRITE | VM_READ]		= PAGE_U_W_R,

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	[VM_SHARED | VM_EXEC]				= PAGE_U_X_R,

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	[VM_SHARED | VM_EXEC | VM_READ]			= PAGE_U_X_R,

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	[VM_SHARED | VM_EXEC | VM_WRITE]		= PAGE_U_X_W_R,

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	[VM_SHARED | VM_EXEC | VM_WRITE | VM_READ]	= PAGE_U_X_W_R

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};

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DECLARE_VM_GET_PAGE_PROT

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