4 * Copyright (C) 2008 - 2009 Paul Mundt
6 * This file is subject to the terms and conditions of the GNU General Public
7 * License. See the file "COPYING" in the main directory of this archive
12 #include <linux/mman.h>
13 #include <linux/module.h>
15 #include <asm/processor.h>
17 unsigned long shm_align_mask = PAGE_SIZE - 1; /* Sane caches */
18 EXPORT_SYMBOL(shm_align_mask);
22 * To avoid cache aliases, we map the shared page with same color.
24 static inline unsigned long COLOUR_ALIGN(unsigned long addr,
27 unsigned long base = (addr + shm_align_mask) & ~shm_align_mask;
28 unsigned long off = (pgoff << PAGE_SHIFT) & shm_align_mask;
33 unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr,
34 unsigned long len, unsigned long pgoff, unsigned long flags)
36 struct mm_struct *mm = current->mm;
37 struct vm_area_struct *vma;
39 struct vm_unmapped_area_info info;
41 if (flags & MAP_FIXED) {
42 /* We do not accept a shared mapping if it would violate
43 * cache aliasing constraints.
45 if ((flags & MAP_SHARED) &&
46 ((addr - (pgoff << PAGE_SHIFT)) & shm_align_mask))
51 if (unlikely(len > TASK_SIZE))
55 if (filp || (flags & MAP_SHARED))
60 addr = COLOUR_ALIGN(addr, pgoff);
62 addr = PAGE_ALIGN(addr);
64 vma = find_vma(mm, addr);
65 if (TASK_SIZE - len >= addr &&
66 (!vma || addr + len <= vma->vm_start))
72 info.low_limit = TASK_UNMAPPED_BASE;
73 info.high_limit = TASK_SIZE;
74 info.align_mask = do_colour_align ? (PAGE_MASK & shm_align_mask) : 0;
75 info.align_offset = pgoff << PAGE_SHIFT;
76 return vm_unmapped_area(&info);
80 arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
81 const unsigned long len, const unsigned long pgoff,
82 const unsigned long flags)
84 struct vm_area_struct *vma;
85 struct mm_struct *mm = current->mm;
86 unsigned long addr = addr0;
88 struct vm_unmapped_area_info info;
90 if (flags & MAP_FIXED) {
91 /* We do not accept a shared mapping if it would violate
92 * cache aliasing constraints.
94 if ((flags & MAP_SHARED) &&
95 ((addr - (pgoff << PAGE_SHIFT)) & shm_align_mask))
100 if (unlikely(len > TASK_SIZE))
104 if (filp || (flags & MAP_SHARED))
107 /* requesting a specific address */
110 addr = COLOUR_ALIGN(addr, pgoff);
112 addr = PAGE_ALIGN(addr);
114 vma = find_vma(mm, addr);
115 if (TASK_SIZE - len >= addr &&
116 (!vma || addr + len <= vma->vm_start))
120 info.flags = VM_UNMAPPED_AREA_TOPDOWN;
122 info.low_limit = PAGE_SIZE;
123 info.high_limit = mm->mmap_base;
124 info.align_mask = do_colour_align ? (PAGE_MASK & shm_align_mask) : 0;
125 info.align_offset = pgoff << PAGE_SHIFT;
126 addr = vm_unmapped_area(&info);
129 * A failed mmap() very likely causes application failure,
130 * so fall back to the bottom-up function here. This scenario
131 * can happen with large stack limits and large mmap()
134 if (addr & ~PAGE_MASK) {
135 VM_BUG_ON(addr != -ENOMEM);
137 info.low_limit = TASK_UNMAPPED_BASE;
138 info.high_limit = TASK_SIZE;
139 addr = vm_unmapped_area(&info);
144 #endif /* CONFIG_MMU */
147 * You really shouldn't be using read() or write() on /dev/mem. This
148 * might go away in the future.
150 int valid_phys_addr_range(phys_addr_t addr, size_t count)
152 if (addr < __MEMORY_START)
154 if (addr + count > __pa(high_memory))
160 int valid_mmap_phys_addr_range(unsigned long pfn, size_t size)