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/sched/mm.h>
  13 #include <linux/mman.h>
  14 #include <linux/module.h>
  15 #include <asm/page.h>
  16 #include <asm/processor.h>
  17
  18 unsigned long shm_align_mask = PAGE_SIZE - 1;   /* Sane caches */
  19 EXPORT_SYMBOL(shm_align_mask);
  20
  21 #ifdef CONFIG_MMU
  22 static const pgprot_t protection_map[16] = {
  23         [VM_NONE]                                       = PAGE_NONE,
  24         [VM_READ]                                       = PAGE_READONLY,
  25         [VM_WRITE]                                      = PAGE_COPY,
  26         [VM_WRITE | VM_READ]                            = PAGE_COPY,
  27         [VM_EXEC]                                       = PAGE_EXECREAD,
  28         [VM_EXEC | VM_READ]                             = PAGE_EXECREAD,
  29         [VM_EXEC | VM_WRITE]                            = PAGE_COPY,
  30         [VM_EXEC | VM_WRITE | VM_READ]                  = PAGE_COPY,
  31         [VM_SHARED]                                     = PAGE_NONE,
  32         [VM_SHARED | VM_READ]                           = PAGE_READONLY,
  33         [VM_SHARED | VM_WRITE]                          = PAGE_WRITEONLY,
  34         [VM_SHARED | VM_WRITE | VM_READ]                = PAGE_SHARED,
  35         [VM_SHARED | VM_EXEC]                           = PAGE_EXECREAD,
  36         [VM_SHARED | VM_EXEC | VM_READ]                 = PAGE_EXECREAD,
  37         [VM_SHARED | VM_EXEC | VM_WRITE]                = PAGE_RWX,
  38         [VM_SHARED | VM_EXEC | VM_WRITE | VM_READ]      = PAGE_RWX
  39 };
  40 DECLARE_VM_GET_PAGE_PROT
  41
  42 /*
  43  * To avoid cache aliases, we map the shared page with same color.
  44  */
  45 static inline unsigned long COLOUR_ALIGN(unsigned long addr,
  46                                          unsigned long pgoff)
  47 {
  48         unsigned long base = (addr + shm_align_mask) & ~shm_align_mask;
  49         unsigned long off = (pgoff << PAGE_SHIFT) & shm_align_mask;
  50
  51         return base + off;
  52 }
  53
  54 unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr,
  55         unsigned long len, unsigned long pgoff, unsigned long flags)
  56 {
  57         struct mm_struct *mm = current->mm;
  58         struct vm_area_struct *vma;
  59         int do_colour_align;
  60         struct vm_unmapped_area_info info = {};
  61
  62         if (flags & MAP_FIXED) {
  63                 /* We do not accept a shared mapping if it would violate
  64                  * cache aliasing constraints.
  65                  */
  66                 if ((flags & MAP_SHARED) &&
  67                     ((addr - (pgoff << PAGE_SHIFT)) & shm_align_mask))
  68                         return -EINVAL;
  69                 return addr;
  70         }
  71
  72         if (unlikely(len > TASK_SIZE))
  73                 return -ENOMEM;
  74
  75         do_colour_align = 0;
  76         if (filp || (flags & MAP_SHARED))
  77                 do_colour_align = 1;
  78
  79         if (addr) {
  80                 if (do_colour_align)
  81                         addr = COLOUR_ALIGN(addr, pgoff);
  82                 else
  83                         addr = PAGE_ALIGN(addr);
  84
  85                 vma = find_vma(mm, addr);
  86                 if (TASK_SIZE - len >= addr &&
  87                     (!vma || addr + len <= vm_start_gap(vma)))
  88                         return addr;
  89         }
  90
  91         info.length = len;
  92         info.low_limit = TASK_UNMAPPED_BASE;
  93         info.high_limit = TASK_SIZE;
  94         info.align_mask = do_colour_align ? (PAGE_MASK & shm_align_mask) : 0;
  95         info.align_offset = pgoff << PAGE_SHIFT;
  96         return vm_unmapped_area(&info);
  97 }
  98
  99 unsigned long
 100 arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
 101                           const unsigned long len, const unsigned long pgoff,
 102                           const unsigned long flags)
 103 {
 104         struct vm_area_struct *vma;
 105         struct mm_struct *mm = current->mm;
 106         unsigned long addr = addr0;
 107         int do_colour_align;
 108         struct vm_unmapped_area_info info = {};
 109
 110         if (flags & MAP_FIXED) {
 111                 /* We do not accept a shared mapping if it would violate
 112                  * cache aliasing constraints.
 113                  */
 114                 if ((flags & MAP_SHARED) &&
 115                     ((addr - (pgoff << PAGE_SHIFT)) & shm_align_mask))
 116                         return -EINVAL;
 117                 return addr;
 118         }
 119
 120         if (unlikely(len > TASK_SIZE))
 121                 return -ENOMEM;
 122
 123         do_colour_align = 0;
 124         if (filp || (flags & MAP_SHARED))
 125                 do_colour_align = 1;
 126
 127         /* requesting a specific address */
 128         if (addr) {
 129                 if (do_colour_align)
 130                         addr = COLOUR_ALIGN(addr, pgoff);
 131                 else
 132                         addr = PAGE_ALIGN(addr);
 133
 134                 vma = find_vma(mm, addr);
 135                 if (TASK_SIZE - len >= addr &&
 136                     (!vma || addr + len <= vm_start_gap(vma)))
 137                         return addr;
 138         }
 139
 140         info.flags = VM_UNMAPPED_AREA_TOPDOWN;
 141         info.length = len;
 142         info.low_limit = PAGE_SIZE;
 143         info.high_limit = mm->mmap_base;
 144         info.align_mask = do_colour_align ? (PAGE_MASK & shm_align_mask) : 0;
 145         info.align_offset = pgoff << PAGE_SHIFT;
 146         addr = vm_unmapped_area(&info);
 147
 148         /*
 149          * A failed mmap() very likely causes application failure,
 150          * so fall back to the bottom-up function here. This scenario
 151          * can happen with large stack limits and large mmap()
 152          * allocations.
 153          */
 154         if (addr & ~PAGE_MASK) {
 155                 VM_BUG_ON(addr != -ENOMEM);
 156                 info.flags = 0;
 157                 info.low_limit = TASK_UNMAPPED_BASE;
 158                 info.high_limit = TASK_SIZE;
 159                 addr = vm_unmapped_area(&info);
 160         }
 161
 162         return addr;
 163 }
 164 #endif /* CONFIG_MMU */
 165
 166 /*
 167  * You really shouldn't be using read() or write() on /dev/mem.  This
 168  * might go away in the future.
 169  */
 170 int valid_phys_addr_range(phys_addr_t addr, size_t count)
 171 {
 172         if (addr < __MEMORY_START)
 173                 return 0;
 174         if (addr + count > __pa(high_memory))
 175                 return 0;
 176
 177         return 1;
 178 }
 179
 180 int valid_mmap_phys_addr_range(unsigned long pfn, size_t size)
 181 {
 182         return 1;
 183 }