/*
* arch/sh/mm/mmap.c
*
* Copyright (C) 2008 - 2009 Paul Mundt
*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*/
#include <linux/io.h>
#include <linux/mm.h>
#include <linux/mman.h>
#include <linux/module.h>
#include <asm/page.h>
#include <asm/processor.h>
unsigned long shm_align_mask = PAGE_SIZE - 1; /* Sane caches */
EXPORT_SYMBOL(shm_align_mask);
#ifdef CONFIG_MMU
/*
* To avoid cache aliases, we map the shared page with same color.
*/
static inline unsigned long COLOUR_ALIGN(unsigned long addr,
unsigned long pgoff)
{
unsigned long base = (addr + shm_align_mask) & ~shm_align_mask;
unsigned long off = (pgoff << PAGE_SHIFT) & shm_align_mask;
return base + off;
}
static inline unsigned long COLOUR_ALIGN_DOWN(unsigned long addr,
unsigned long pgoff)
{
unsigned long base = addr & ~shm_align_mask;
unsigned long off = (pgoff << PAGE_SHIFT) & shm_align_mask;
if (base + off <= addr)
return base + off;
return base - off;
}
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;
unsigned long start_addr;
int do_colour_align;
if (flags & MAP_FIXED) {
/* We do not accept a shared mapping if it would violate
* cache aliasing constraints.
*/
if ((flags & MAP_SHARED) &&
((addr - (pgoff << PAGE_SHIFT)) & shm_align_mask))
return -EINVAL;
return addr;
}
if (unlikely(len > TASK_SIZE))
return -ENOMEM;
do_colour_align = 0;
if (filp || (flags & MAP_SHARED))
do_colour_align = 1;
if (addr) {
if (do_colour_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;
}
if (len > mm->cached_hole_size) {
start_addr = addr = mm->free_area_cache;
} else {
mm->cached_hole_size = 0;
start_addr = addr = TASK_UNMAPPED_BASE;
}
full_search:
if (do_colour_align)
addr = COLOUR_ALIGN(addr, pgoff);
else
addr = PAGE_ALIGN(mm->free_area_cache);
for (vma = find_vma(mm, addr); ; vma = vma->vm_next) {
/* At this point: (!vma || addr < vma->vm_end). */
if (unlikely(TASK_SIZE - len < addr)) {
/*
* Start a new search - just in case we missed
* some holes.
*/
if (start_addr != TASK_UNMAPPED_BASE) {
start_addr = addr = TASK_UNMAPPED_BASE;
mm->cached_hole_size = 0;
goto full_search;
}
return -ENOMEM;
}
if (likely(!vma || addr + len <= vma->vm_start)) {
/*
* Remember the place where we stopped the search:
*/
mm->free_area_cache = addr + len;
return addr;
}
if (addr + mm->cached_hole_size < vma->vm_start)
mm->cached_hole_size = vma->vm_start - addr;
addr = vma->vm_end;
if (do_colour_align)
addr = COLOUR_ALIGN(addr, pgoff);
}
}
unsigned long
arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
const unsigned long len, const unsigned long pgoff,
const unsigned long flags)
{
struct vm_area_struct *vma;
struct mm_struct *mm = current->mm;
unsigned long addr = addr0;
int do_colour_align;
if (flags & MAP_FIXED) {
/* We do not accept a shared mapping if it would violate
* cache aliasing constraints.
*/
if ((flags & MAP_SHARED) &&
((addr - (pgoff << PAGE_SHIFT)) & shm_align_mask))
return -EINVAL;
return addr;
}
if (unlikely(len > TASK_SIZE))
return -ENOMEM;
do_colour_align = 0;
if (filp || (flags & MAP_SHARED))
do_colour_align = 1;
/* requesting a specific address */
if (addr) {
if (do_colour_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;
}
/* check if free_area_cache is useful for us */
if (len <= mm->cached_hole_size) {
mm->cached_hole_size = 0;
mm->free_area_cache = mm->mmap_base;
}
/* either no address requested or can't fit in requested address hole */
addr = mm->free_area_cache;
if (do_colour_align) {
unsigned long base = COLOUR_ALIGN_DOWN(addr-len, pgoff);
addr = base + len;
}
/* make sure it can fit in the remaining address space */
if (likely(addr > len)) {
vma = find_vma(mm, addr-len);
if (!vma || addr <= vma->vm_start) {
/* remember the address as a hint for next time */
return (mm->free_area_cache = addr-len);
}
}
if (unlikely(mm->mmap_base < len))
goto bottomup;
addr = mm->mmap_base-len;
if (do_colour_align)
addr = COLOUR_ALIGN_DOWN(addr, pgoff);
do {
/*
* Lookup failure means no vma is above this address,
* else if new region fits below vma->vm_start,
* return with success:
*/
vma = find_vma(mm, addr);
if (likely(!vma || addr+len <= vma->vm_start)) {
/* remember the address as a hint for next time */
return (mm->free_area_cache = addr);
}
/* remember the largest hole we saw so far */
if (addr + mm->cached_hole_size < vma->vm_start)
mm->cached_hole_size = vma->vm_start - addr;
/* try just below the current vma->vm_start */
addr = vma->vm_start-len;
if (do_colour_align)
addr = COLOUR_ALIGN_DOWN(addr, pgoff);
} while (likely(len < vma->vm_start));
bottomup:
/*
* A failed mmap() very likely causes application failure,
* so fall back to the bottom-up function here. This scenario
* can happen with large stack limits and large mmap()
* allocations.
*/
mm->cached_hole_size = ~0UL;
mm->free_area_cache = TASK_UNMAPPED_BASE;
addr = arch_get_unmapped_area(filp, addr0, len, pgoff, flags);
/*
* Restore the topdown base:
*/
mm->free_area_cache = mm->mmap_base;
mm->cached_hole_size = ~0UL;
return addr;
}
#endif /* CONFIG_MMU */
/*
* You really shouldn't be using read() or write() on /dev/mem. This
* might go away in the future.
*/
int valid_phys_addr_range(unsigned long addr, size_t count)
{
if (addr < __MEMORY_START)
return 0;
if (addr + count > __pa(high_memory))
return 0;
return 1;
}
int valid_mmap_phys_addr_range(unsigned long pfn, size_t size)
{
return 1;
}
