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  */
  24 unsigned long
  25 arch_get_unmapped_area(struct file *filp, unsigned long addr,
  26                 unsigned long len, unsigned long pgoff,
  27                 unsigned long flags, vm_flags_t vm_flags)
  28 {
  29         struct mm_struct *mm = current->mm;
  30         struct vm_area_struct *vma;
  31         int do_align = 0;
  32         struct vm_unmapped_area_info info = {
  33                 .length = len,
  34                 .low_limit = mm->mmap_base,
  35                 .high_limit = TASK_SIZE,
  36                 .align_offset = pgoff << PAGE_SHIFT
  37         };
  38
  39         /*
  40          * We only need to do colour alignment if either the I or D
  41          * caches alias.
  42          */
  43         do_align = filp || (flags & MAP_SHARED);
  44
  45         /*
  46          * We enforce the MAP_FIXED case.
  47          */
  48         if (flags & MAP_FIXED) {
  49                 if (flags & MAP_SHARED &&
  50                     (addr - (pgoff << PAGE_SHIFT)) & (SHMLBA - 1))
  51                         return -EINVAL;
  52                 return addr;
  53         }
  54
  55         if (len > TASK_SIZE)
  56                 return -ENOMEM;
  57
  58         if (addr) {
  59                 if (do_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 <= vm_start_gap(vma)))
  67                         return addr;
  68         }
  69
  70         info.align_mask = do_align ? (PAGE_MASK & (SHMLBA - 1)) : 0;
  71         return vm_unmapped_area(&info);
  72 }