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.flags = 0;
  92         info.length = len;
  93         info.low_limit = TASK_UNMAPPED_BASE;
  94         info.high_limit = TASK_SIZE;
  95         info.align_mask = do_colour_align ? (PAGE_MASK & shm_align_mask) : 0;
  96         info.align_offset = pgoff << PAGE_SHIFT;
  97         return vm_unmapped_area(&info);
  98 }
  99
 100 unsigned long
 101 arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
 102                           const unsigned long len, const unsigned long pgoff,
 103                           const unsigned long flags)
 104 {
 105         struct vm_area_struct *vma;
 106         struct mm_struct *mm = current->mm;
 107         unsigned long addr = addr0;
 108         int do_colour_align;
 109         struct vm_unmapped_area_info info;
 110
 111         if (flags & MAP_FIXED) {
 112                 /* We do not accept a shared mapping if it would violate
 113                  * cache aliasing constraints.
 114                  */
 115                 if ((flags & MAP_SHARED) &&
 116                     ((addr - (pgoff << PAGE_SHIFT)) & shm_align_mask))
 117                         return -EINVAL;
 118                 return addr;
 119         }
 120
 121         if (unlikely(len > TASK_SIZE))
 122                 return -ENOMEM;
 123
 124         do_colour_align = 0;
 125         if (filp || (flags & MAP_SHARED))
 126                 do_colour_align = 1;
 127
 128         /* requesting a specific address */
 129         if (addr) {
 130                 if (do_colour_align)
 131                         addr = COLOUR_ALIGN(addr, pgoff);
 132                 else
 133                         addr = PAGE_ALIGN(addr);
 134
 135                 vma = find_vma(mm, addr);
 136                 if (TASK_SIZE - len >= addr &&
 137                     (!vma || addr + len <= vm_start_gap(vma)))
 138                         return addr;
 139         }
 140
 141         info.flags = VM_UNMAPPED_AREA_TOPDOWN;
 142         info.length = len;
 143         info.low_limit = PAGE_SIZE;
 144         info.high_limit = mm->mmap_base;
 145         info.align_mask = do_colour_align ? (PAGE_MASK & shm_align_mask) : 0;
 146         info.align_offset = pgoff << PAGE_SHIFT;
 147         addr = vm_unmapped_area(&info);
 148
 149         /*
 150          * A failed mmap() very likely causes application failure,
 151          * so fall back to the bottom-up function here. This scenario
 152          * can happen with large stack limits and large mmap()
 153          * allocations.
 154          */
 155         if (addr & ~PAGE_MASK) {
 156                 VM_BUG_ON(addr != -ENOMEM);
 157                 info.flags = 0;
 158                 info.low_limit = TASK_UNMAPPED_BASE;
 159                 info.high_limit = TASK_SIZE;
 160                 addr = vm_unmapped_area(&info);
 161         }
 162
 163         return addr;
 164 }
 165 #endif /* CONFIG_MMU */
 166
 167 /*
 168  * You really shouldn't be using read() or write() on /dev/mem.  This
 169  * might go away in the future.
 170  */
 171 int valid_phys_addr_range(phys_addr_t addr, size_t count)
 172 {
 173         if (addr < __MEMORY_START)
 174                 return 0;
 175         if (addr + count > __pa(high_memory))
 176                 return 0;
 177
 178         return 1;
 179 }
 180
 181 int valid_mmap_phys_addr_range(unsigned long pfn, size_t size)
 182 {
 183         return 1;
 184 }