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
  17 unsigned long shm_align_mask = PAGE_SIZE - 1;   /* Sane caches */
  18 EXPORT_SYMBOL(shm_align_mask);
  19
  20 #ifdef CONFIG_MMU
  21 /*
  22  * To avoid cache aliases, we map the shared page with same color.
  23  */
  24 static 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
  33 unsigned 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
  79 unsigned long
  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)
  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  */
 150 int 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
 160 int valid_mmap_phys_addr_range(unsigned long pfn, size_t size)
 161 {
 162         return 1;
 163 }