[mirror_ubuntu-artful-kernel.git] / arch / arc / mm / mmap.c

/*
 * ARC700 mmap
 *
 * (started from arm version - for VIPT alias handling)
 *
 * Copyright (C) 2013 Synopsys, Inc. (www.synopsys.com)
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/fs.h>
#include <linux/mm.h>
#include <linux/mman.h>
#include <linux/sched/mm.h>

#include <asm/cacheflush.h>

#define COLOUR_ALIGN(addr, pgoff)			\
	((((addr) + SHMLBA - 1) & ~(SHMLBA - 1)) +	\
	 (((pgoff) << PAGE_SHIFT) & (SHMLBA - 1)))

/*
 * Ensure that shared mappings are correctly aligned to
 * avoid aliasing issues with VIPT caches.
 * We need to ensure that
 * a specific page of an object is always mapped at a multiple of
 * SHMLBA bytes.
 */
unsigned long
arch_get_unmapped_area(struct file *filp, unsigned long addr,
		unsigned long len, unsigned long pgoff, unsigned long flags)
{
	struct mm_struct *mm = current->mm;
	struct vm_area_struct *vma;
	int do_align = 0;
	int aliasing = cache_is_vipt_aliasing();
	struct vm_unmapped_area_info info;

	/*
	 * We only need to do colour alignment if D cache aliases.
	 */
	if (aliasing)
		do_align = filp || (flags & MAP_SHARED);

	/*
	 * We enforce the MAP_FIXED case.
	 */
	if (flags & MAP_FIXED) {
		if (aliasing && flags & MAP_SHARED &&
		    (addr - (pgoff << PAGE_SHIFT)) & (SHMLBA - 1))
			return -EINVAL;
		return addr;
	}

	if (len > TASK_SIZE)
		return -ENOMEM;

	if (addr) {
		if (do_align)
			addr = COLOUR_ALIGN(addr, pgoff);
		else
			addr = PAGE_ALIGN(addr);

		vma = find_vma(mm, addr);
		if (TASK_SIZE - len >= addr &&
		    (!vma || addr + len <= vm_start_gap(vma)))
			return addr;
	}

	info.flags = 0;
	info.length = len;
	info.low_limit = mm->mmap_base;
	info.high_limit = TASK_SIZE;
	info.align_mask = do_align ? (PAGE_MASK & (SHMLBA - 1)) : 0;
	info.align_offset = pgoff << PAGE_SHIFT;
	return vm_unmapped_area(&info);
}
Commit	Line	Data
5bba49f5 VG	1	/*
	2	* ARC700 mmap
	3	*
	4	* (started from arm version - for VIPT alias handling)
	5	*
	6	* Copyright (C) 2013 Synopsys, Inc. (www.synopsys.com)
	7	*
	8	* This program is free software; you can redistribute it and/or modify
	9	* it under the terms of the GNU General Public License version 2 as
	10	* published by the Free Software Foundation.
	11	*/
	12
	13	#include <linux/fs.h>
	14	#include <linux/mm.h>
	15	#include <linux/mman.h>
01042607 IM	16	#include <linux/sched/mm.h>
01042607 IM	17
5bba49f5 VG	18	#include <asm/cacheflush.h>
	19
	20	#define COLOUR_ALIGN(addr, pgoff) \
	21	((((addr) + SHMLBA - 1) & ~(SHMLBA - 1)) + \
	22	(((pgoff) << PAGE_SHIFT) & (SHMLBA - 1)))
	23
	24	/*
	25	* Ensure that shared mappings are correctly aligned to
	26	* avoid aliasing issues with VIPT caches.
	27	* We need to ensure that
	28	* a specific page of an object is always mapped at a multiple of
	29	* SHMLBA bytes.
	30	*/
	31	unsigned long
	32	arch_get_unmapped_area(struct file *filp, unsigned long addr,
	33	unsigned long len, unsigned long pgoff, unsigned long flags)
	34	{
	35	struct mm_struct *mm = current->mm;
	36	struct vm_area_struct *vma;
	37	int do_align = 0;
	38	int aliasing = cache_is_vipt_aliasing();
	39	struct vm_unmapped_area_info info;
	40
	41	/*
	42	* We only need to do colour alignment if D cache aliases.
	43	*/
	44	if (aliasing)
	45	do_align = filp \|\| (flags & MAP_SHARED);
	46
	47	/*
	48	* We enforce the MAP_FIXED case.
	49	*/
	50	if (flags & MAP_FIXED) {
	51	if (aliasing && flags & MAP_SHARED &&
	52	(addr - (pgoff << PAGE_SHIFT)) & (SHMLBA - 1))
	53	return -EINVAL;
	54	return addr;
	55	}
	56
	57	if (len > TASK_SIZE)
	58	return -ENOMEM;
	59
	60	if (addr) {
	61	if (do_align)
	62	addr = COLOUR_ALIGN(addr, pgoff);
	63	else
	64	addr = PAGE_ALIGN(addr);
	65
	66	vma = find_vma(mm, addr);
	67	if (TASK_SIZE - len >= addr &&
1be7107f	68	(!vma \|\| addr + len <= vm_start_gap(vma)))
5bba49f5 VG	69	return addr;
	70	}
	71
	72	info.flags = 0;
	73	info.length = len;
	74	info.low_limit = mm->mmap_base;
	75	info.high_limit = TASK_SIZE;
	76	info.align_mask = do_align ? (PAGE_MASK & (SHMLBA - 1)) : 0;
	77	info.align_offset = pgoff << PAGE_SHIFT;
	78	return vm_unmapped_area(&info);
	79	}