LXR linux/arch/mips/mm/mmap.c

   1/*
   2 * This file is subject to the terms and conditions of the GNU General Public
   3 * License.  See the file "COPYING" in the main directory of this archive
   4 * for more details.
   5 *
   6 * Copyright (C) 2011 Wind River Systems,
   7 *   written by Ralf Baechle <ralf@linux-mips.org>
   8 */
   9#include <linux/compiler.h>
  10#include <linux/elf-randomize.h>
  11#include <linux/errno.h>
  12#include <linux/mm.h>
  13#include <linux/mman.h>
  14#include <linux/export.h>
  15#include <linux/personality.h>
  16#include <linux/random.h>
  17#include <linux/sched/signal.h>
  18#include <linux/sched/mm.h>
  19
  20unsigned long shm_align_mask = PAGE_SIZE - 1;   /* Sane caches */
  21EXPORT_SYMBOL(shm_align_mask);
  22
  23#define COLOUR_ALIGN(addr, pgoff)                               \
  24        ((((addr) + shm_align_mask) & ~shm_align_mask) +        \
  25         (((pgoff) << PAGE_SHIFT) & shm_align_mask))
  26
  27enum mmap_allocation_direction {UP, DOWN};
  28
  29static unsigned long arch_get_unmapped_area_common(struct file *filp,
  30        unsigned long addr0, unsigned long len, unsigned long pgoff,
  31        unsigned long flags, enum mmap_allocation_direction dir)
  32{
  33        struct mm_struct *mm = current->mm;
  34        struct vm_area_struct *vma;
  35        unsigned long addr = addr0;
  36        int do_color_align;
  37        struct vm_unmapped_area_info info;
  38
  39        if (unlikely(len > TASK_SIZE))
  40                return -ENOMEM;
  41
  42        if (flags & MAP_FIXED) {
  43                /* Even MAP_FIXED mappings must reside within TASK_SIZE */
  44                if (TASK_SIZE - len < addr)
  45                        return -EINVAL;
  46
  47                /*
  48                 * We do not accept a shared mapping if it would violate
  49                 * cache aliasing constraints.
  50                 */
  51                if ((flags & MAP_SHARED) &&
  52                    ((addr - (pgoff << PAGE_SHIFT)) & shm_align_mask))
  53                        return -EINVAL;
  54                return addr;
  55        }
  56
  57        do_color_align = 0;
  58        if (filp || (flags & MAP_SHARED))
  59                do_color_align = 1;
  60
  61        /* requesting a specific address */
  62        if (addr) {
  63                if (do_color_align)
  64                        addr = COLOUR_ALIGN(addr, pgoff);
  65                else
  66                        addr = PAGE_ALIGN(addr);
  67
  68                vma = find_vma(mm, addr);
  69                if (TASK_SIZE - len >= addr &&
  70                    (!vma || addr + len <= vm_start_gap(vma)))
  71                        return addr;
  72        }
  73
  74        info.length = len;
  75        info.align_mask = do_color_align ? (PAGE_MASK & shm_align_mask) : 0;
  76        info.align_offset = pgoff << PAGE_SHIFT;
  77
  78        if (dir == DOWN) {
  79                info.flags = VM_UNMAPPED_AREA_TOPDOWN;
  80                info.low_limit = PAGE_SIZE;
  81                info.high_limit = mm->mmap_base;
  82                addr = vm_unmapped_area(&info);
  83
  84                if (!(addr & ~PAGE_MASK))
  85                        return addr;
  86
  87                /*
  88                 * A failed mmap() very likely causes application failure,
  89                 * so fall back to the bottom-up function here. This scenario
  90                 * can happen with large stack limits and large mmap()
  91                 * allocations.
  92                 */
  93        }
  94
  95        info.flags = 0;
  96        info.low_limit = mm->mmap_base;
  97        info.high_limit = TASK_SIZE;
  98        return vm_unmapped_area(&info);
  99}
 100
 101unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr0,
 102        unsigned long len, unsigned long pgoff, unsigned long flags)
 103{
 104        return arch_get_unmapped_area_common(filp,
 105                        addr0, len, pgoff, flags, UP);
 106}
 107
 108/*
 109 * There is no need to export this but sched.h declares the function as
 110 * extern so making it static here results in an error.
 111 */
 112unsigned long arch_get_unmapped_area_topdown(struct file *filp,
 113        unsigned long addr0, unsigned long len, unsigned long pgoff,
 114        unsigned long flags)
 115{
 116        return arch_get_unmapped_area_common(filp,
 117                        addr0, len, pgoff, flags, DOWN);
 118}
 119
 120bool __virt_addr_valid(const volatile void *kaddr)
 121{
 122        unsigned long vaddr = (unsigned long)kaddr;
 123
 124        if ((vaddr < PAGE_OFFSET) || (vaddr >= MAP_BASE))
 125                return false;
 126
 127        return pfn_valid(PFN_DOWN(virt_to_phys(kaddr)));
 128}
 129EXPORT_SYMBOL_GPL(__virt_addr_valid);
 130