LXR linux/arch/sh/mm/mmap.c

   1/*
   2 * arch/sh/mm/mmap.c
   3 *
   4 * Copyright (C) 2008 - 2009  Paul Mundt
   5 *
   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
   8 * for more details.
   9 */
  10#include <linux/io.h>
  11#include <linux/mm.h>
  12#include <linux/mman.h>
  13#include <linux/module.h>
  14#include <asm/page.h>
  15#include <asm/processor.h>
  16
  17unsigned long shm_align_mask = PAGE_SIZE - 1;   /* Sane caches */
  18EXPORT_SYMBOL(shm_align_mask);
  19
  20#ifdef CONFIG_MMU
  21/*
  22 * To avoid cache aliases, we map the shared page with same color.
  23 */
  24static inline unsigned long COLOUR_ALIGN(unsigned long addr,
  25                                         unsigned long pgoff)
  26{
  27        unsigned long base = (addr + shm_align_mask) & ~shm_align_mask;
  28        unsigned long off = (pgoff << PAGE_SHIFT) & shm_align_mask;
  29
  30        return base + off;
  31}
  32
  33unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr,
  34        unsigned long len, unsigned long pgoff, unsigned long flags)
  35{
  36        struct mm_struct *mm = current->mm;
  37        struct vm_area_struct *vma;
  38        int do_colour_align;
  39        struct vm_unmapped_area_info info;
  40
  41        if (flags & MAP_FIXED) {
  42                /* We do not accept a shared mapping if it would violate
  43                 * cache aliasing constraints.
  44                 */
  45                if ((flags & MAP_SHARED) &&
  46                    ((addr - (pgoff << PAGE_SHIFT)) & shm_align_mask))
  47                        return -EINVAL;
  48                return addr;
  49        }
  50
  51        if (unlikely(len > TASK_SIZE))
  52                return -ENOMEM;
  53
  54        do_colour_align = 0;
  55        if (filp || (flags & MAP_SHARED))
  56                do_colour_align = 1;
  57
  58        if (addr) {
  59                if (do_colour_align)
  60                        addr = COLOUR_ALIGN(addr, pgoff);
  61                else
  62                        addr = PAGE_ALIGN(addr);
  63
  64                vma = find_vma(mm, addr);
  65                if (TASK_SIZE - len >= addr &&
  66                    (!vma || addr + len <= vma->vm_start))
  67                        return addr;
  68        }
  69
  70        info.flags = 0;
  71        info.length = len;
  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);
  77}
  78
  79unsigned long
  80arch_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)
  83{
  84        struct vm_area_struct *vma;
  85        struct mm_struct *mm = current->mm;
  86        unsigned long addr = addr0;
  87        int do_colour_align;
  88        struct vm_unmapped_area_info info;
  89
  90        if (flags & MAP_FIXED) {
  91                /* We do not accept a shared mapping if it would violate
  92                 * cache aliasing constraints.
  93                 */
  94                if ((flags & MAP_SHARED) &&
  95                    ((addr - (pgoff << PAGE_SHIFT)) & shm_align_mask))
  96                        return -EINVAL;
  97                return addr;
  98        }
  99
 100        if (unlikely(len > TASK_SIZE))
 101                return -ENOMEM;
 102
 103        do_colour_align = 0;
 104        if (filp || (flags & MAP_SHARED))
 105                do_colour_align = 1;
 106
 107        /* requesting a specific address */
 108        if (addr) {
 109                if (do_colour_align)
 110                        addr = COLOUR_ALIGN(addr, pgoff);
 111                else
 112                        addr = PAGE_ALIGN(addr);
 113
 114                vma = find_vma(mm, addr);
 115                if (TASK_SIZE - len >= addr &&
 116                    (!vma || addr + len <= vma->vm_start))
 117                        return addr;
 118        }
 119
 120        info.flags = VM_UNMAPPED_AREA_TOPDOWN;
 121        info.length = len;
 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);
 127
 128        /*
 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()
 132         * allocations.
 133         */
 134        if (addr & ~PAGE_MASK) {
 135                VM_BUG_ON(addr != -ENOMEM);
 136                info.flags = 0;
 137                info.low_limit = TASK_UNMAPPED_BASE;
 138                info.high_limit = TASK_SIZE;
 139                addr = vm_unmapped_area(&info);
 140        }
 141
 142        return addr;
 143}
 144#endif /* CONFIG_MMU */
 145
 146/*
 147 * You really shouldn't be using read() or write() on /dev/mem.  This
 148 * might go away in the future.
 149 */
 150int valid_phys_addr_range(phys_addr_t addr, size_t count)
 151{
 152        if (addr < __MEMORY_START)
 153                return 0;
 154        if (addr + count > __pa(high_memory))
 155                return 0;
 156
 157        return 1;
 158}
 159
 160int valid_mmap_phys_addr_range(unsigned long pfn, size_t size)
 161{
 162        return 1;
 163}
 164