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/*
* arch / sh / mm / mmap . c
*
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* Copyright ( C ) 2008 - 2009 Paul Mundt
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*
* 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>
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# include <linux/mman.h>
# include <linux/module.h>
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# include <asm/page.h>
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# include <asm/processor.h>
unsigned long shm_align_mask = PAGE_SIZE - 1 ; /* Sane caches */
EXPORT_SYMBOL ( shm_align_mask ) ;
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# ifdef CONFIG_MMU
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/*
* To avoid cache aliases , we map the shared page with same color .
*/
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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 ;
}
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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 .
*/
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if ( ( flags & MAP_SHARED ) & &
( ( addr - ( pgoff < < PAGE_SHIFT ) ) & shm_align_mask ) )
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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 ) ;
}
}
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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 ;
}
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# endif /* CONFIG_MMU */
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/*
* 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 )
{
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if ( addr < __MEMORY_START )
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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 ;
}