mirror of
https://mirrors.bfsu.edu.cn/git/linux.git
synced 2024-11-17 17:24:17 +08:00
5bba49f539
Enforce congruency of userspace shared mappings Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
79 lines
1.9 KiB
C
79 lines
1.9 KiB
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 <= vma->vm_start))
|
|
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);
|
|
}
|