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Linux/arch/sh/mm/mmap.c

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  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 }
164 

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