root/arch/sh/mm/mmap.c

DEFINITIONS

1. COLOUR_ALIGN
2. arch_get_unmapped_area
3. arch_get_unmapped_area_topdown
4. valid_phys_addr_range
5. valid_mmap_phys_addr_range

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