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/sched/mm.h>
  13#include <linux/mman.h>
  14#include <linux/module.h>
  15#include <asm/page.h>
  16#include <asm/processor.h>
  17
  18unsigned long shm_align_mask = PAGE_SIZE - 1;   /* Sane caches */
  19EXPORT_SYMBOL(shm_align_mask);
  20
  21#ifdef CONFIG_MMU
  22/*
  23 * To avoid cache aliases, we map the shared page with same color.
  24 */
  25static 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
  34unsigned 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
  80unsigned long
  81arch_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 */
 151int 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
 161int valid_mmap_phys_addr_range(unsigned long pfn, size_t size)
 162{
 163        return 1;
 164}
 165