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git.proxmox.com Git - mirror_ubuntu-eoan-kernel.git/blob - arch/arm/mm/mmap.c
2 * linux/arch/arm/mm/mmap.c
6 #include <linux/mman.h>
8 #include <linux/sched.h>
9 #include <asm/system.h>
11 #define COLOUR_ALIGN(addr,pgoff) \
12 ((((addr)+SHMLBA-1)&~(SHMLBA-1)) + \
13 (((pgoff)<<PAGE_SHIFT) & (SHMLBA-1)))
16 * We need to ensure that shared mappings are correctly aligned to
17 * avoid aliasing issues with VIPT caches. We need to ensure that
18 * a specific page of an object is always mapped at a multiple of
21 * We unconditionally provide this function for all cases, however
22 * in the VIVT case, we optimise out the alignment rules.
25 arch_get_unmapped_area(struct file
*filp
, unsigned long addr
,
26 unsigned long len
, unsigned long pgoff
, unsigned long flags
)
28 struct mm_struct
*mm
= current
->mm
;
29 struct vm_area_struct
*vma
;
30 unsigned long start_addr
;
32 unsigned int cache_type
;
33 int do_align
= 0, aliasing
= 0;
36 * We only need to do colour alignment if either the I or D
37 * caches alias. This is indicated by bits 9 and 21 of the
38 * cache type register.
40 cache_type
= read_cpuid(CPUID_CACHETYPE
);
41 if (cache_type
!= read_cpuid(CPUID_ID
)) {
42 aliasing
= (cache_type
| cache_type
>> 12) & (1 << 11);
44 do_align
= filp
|| flags
& MAP_SHARED
;
52 * We enforce the MAP_FIXED case.
54 if (flags
& MAP_FIXED
) {
55 if (aliasing
&& flags
& MAP_SHARED
&& addr
& (SHMLBA
- 1))
65 addr
= COLOUR_ALIGN(addr
, pgoff
);
67 addr
= PAGE_ALIGN(addr
);
69 vma
= find_vma(mm
, addr
);
70 if (TASK_SIZE
- len
>= addr
&&
71 (!vma
|| addr
+ len
<= vma
->vm_start
))
74 if (len
> mm
->cached_hole_size
) {
75 start_addr
= addr
= mm
->free_area_cache
;
77 start_addr
= addr
= TASK_UNMAPPED_BASE
;
78 mm
->cached_hole_size
= 0;
83 addr
= COLOUR_ALIGN(addr
, pgoff
);
85 addr
= PAGE_ALIGN(addr
);
87 for (vma
= find_vma(mm
, addr
); ; vma
= vma
->vm_next
) {
88 /* At this point: (!vma || addr < vma->vm_end). */
89 if (TASK_SIZE
- len
< addr
) {
91 * Start a new search - just in case we missed
94 if (start_addr
!= TASK_UNMAPPED_BASE
) {
95 start_addr
= addr
= TASK_UNMAPPED_BASE
;
96 mm
->cached_hole_size
= 0;
101 if (!vma
|| addr
+ len
<= vma
->vm_start
) {
103 * Remember the place where we stopped the search:
105 mm
->free_area_cache
= addr
+ len
;
108 if (addr
+ mm
->cached_hole_size
< vma
->vm_start
)
109 mm
->cached_hole_size
= vma
->vm_start
- addr
;
112 addr
= COLOUR_ALIGN(addr
, pgoff
);
118 * You really shouldn't be using read() or write() on /dev/mem. This
119 * might go away in the future.
121 int valid_phys_addr_range(unsigned long addr
, size_t size
)
123 if (addr
+ size
> __pa(high_memory
))
130 * We don't use supersection mappings for mmap() on /dev/mem, which
131 * means that we can't map the memory area above the 4G barrier into
134 int valid_mmap_phys_addr_range(unsigned long pfn
, size_t size
)
136 return !(pfn
+ (size
>> PAGE_SHIFT
) > 0x00100000);