[GitHub/mt8127/android_kernel_alcatel_ttab.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.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>
	16	#include <linux/sched.h>
	17	#include <asm/cacheflush.h>
	18
	19	#define COLOUR_ALIGN(addr, pgoff) \
	20	((((addr) + SHMLBA - 1) & ~(SHMLBA - 1)) + \
	21	(((pgoff) << PAGE_SHIFT) & (SHMLBA - 1)))
	22
	23	/*
	24	* Ensure that shared mappings are correctly aligned to
	25	* avoid aliasing issues with VIPT caches.
	26	* We need to ensure that
	27	* a specific page of an object is always mapped at a multiple of
	28	* SHMLBA bytes.
	29	*/
	30	unsigned long
	31	arch_get_unmapped_area(struct file *filp, unsigned long addr,
	32	unsigned long len, unsigned long pgoff, unsigned long flags)
	33	{
	34	struct mm_struct *mm = current->mm;
	35	struct vm_area_struct *vma;
	36	int do_align = 0;
	37	int aliasing = cache_is_vipt_aliasing();
	38	struct vm_unmapped_area_info info;
	39
	40	/*
	41	* We only need to do colour alignment if D cache aliases.
	42	*/
	43	if (aliasing)
	44	do_align = filp \|\| (flags & MAP_SHARED);
	45
	46	/*
	47	* We enforce the MAP_FIXED case.
	48	*/
	49	if (flags & MAP_FIXED) {
	50	if (aliasing && flags & MAP_SHARED &&
	51	(addr - (pgoff << PAGE_SHIFT)) & (SHMLBA - 1))
	52	return -EINVAL;
	53	return addr;
	54	}
	55
	56	if (len > TASK_SIZE)
	57	return -ENOMEM;
	58
	59	if (addr) {
	60	if (do_align)
	61	addr = COLOUR_ALIGN(addr, pgoff);
	62	else
	63	addr = PAGE_ALIGN(addr);
	64
65	vma = find_vma(mm, addr);
66	if (TASK_SIZE - len >= addr &&
1ad9a25d	67	(!vma \|\| addr + len <= vm_start_gap(vma)))
5bba49f5 VG	68	return addr;
	69	}
	70
	71	info.flags = 0;
	72	info.length = len;
	73	info.low_limit = mm->mmap_base;
	74	info.high_limit = TASK_SIZE;
	75	info.align_mask = do_align ? (PAGE_MASK & (SHMLBA - 1)) : 0;
	76	info.align_offset = pgoff << PAGE_SHIFT;
	77	return vm_unmapped_area(&info);
	78	}