LXR linux/arch/csky/abiv1/mmap.c

   1// SPDX-License-Identifier: GPL-2.0
   2// Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd.
   3
   4#include <linux/fs.h>
   5#include <linux/mm.h>
   6#include <linux/mman.h>
   7#include <linux/shm.h>
   8#include <linux/sched.h>
   9#include <linux/random.h>
  10#include <linux/io.h>
  11
  12#define COLOUR_ALIGN(addr,pgoff)                \
  13        ((((addr)+SHMLBA-1)&~(SHMLBA-1)) +      \
  14         (((pgoff)<<PAGE_SHIFT) & (SHMLBA-1)))
  15
  16/*
  17 * We need to ensure that shared mappings are correctly aligned to
  18 * avoid aliasing issues with VIPT caches.  We need to ensure that
  19 * a specific page of an object is always mapped at a multiple of
  20 * SHMLBA bytes.
  21 *
  22 * We unconditionally provide this function for all cases.
  23 */
  24unsigned long
  25arch_get_unmapped_area(struct file *filp, unsigned long addr,
  26                unsigned long len, unsigned long pgoff, unsigned long flags)
  27{
  28        struct mm_struct *mm = current->mm;
  29        struct vm_area_struct *vma;
  30        int do_align = 0;
  31        struct vm_unmapped_area_info info;
  32
  33        /*
  34         * We only need to do colour alignment if either the I or D
  35         * caches alias.
  36         */
  37        do_align = filp || (flags & MAP_SHARED);
  38
  39        /*
  40         * We enforce the MAP_FIXED case.
  41         */
  42        if (flags & MAP_FIXED) {
  43                if (flags & MAP_SHARED &&
  44                    (addr - (pgoff << PAGE_SHIFT)) & (SHMLBA - 1))
  45                        return -EINVAL;
  46                return addr;
  47        }
  48
  49        if (len > TASK_SIZE)
  50                return -ENOMEM;
  51
  52        if (addr) {
  53                if (do_align)
  54                        addr = COLOUR_ALIGN(addr, pgoff);
  55                else
  56                        addr = PAGE_ALIGN(addr);
  57
  58                vma = find_vma(mm, addr);
  59                if (TASK_SIZE - len >= addr &&
  60                    (!vma || addr + len <= vm_start_gap(vma)))
  61                        return addr;
  62        }
  63
  64        info.flags = 0;
  65        info.length = len;
  66        info.low_limit = mm->mmap_base;
  67        info.high_limit = TASK_SIZE;
  68        info.align_mask = do_align ? (PAGE_MASK & (SHMLBA - 1)) : 0;
  69        info.align_offset = pgoff << PAGE_SHIFT;
  70        return vm_unmapped_area(&info);
  71}
  72