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 unsigned long shm_align_mask = (0x4000 >> 1) - 1;   /* Sane caches */
  13
  14 #define COLOUR_ALIGN(addr, pgoff) \
  15         ((((addr) + shm_align_mask) & ~shm_align_mask) + \
  16          (((pgoff) << PAGE_SHIFT) & shm_align_mask))
  17
  18 unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr,
  19                 unsigned long len, unsigned long pgoff, unsigned long flags)
  20 {
  21         struct vm_area_struct *vmm;
  22         int do_color_align;
  23
  24         if (flags & MAP_FIXED) {
  25                 /*
  26                  * We do not accept a shared mapping if it would violate
  27                  * cache aliasing constraints.
  28                  */
  29                 if ((flags & MAP_SHARED) &&
  30                         ((addr - (pgoff << PAGE_SHIFT)) & shm_align_mask))
  31                         return -EINVAL;
  32                 return addr;
  33         }
  34
  35         if (len > TASK_SIZE)
  36                 return -ENOMEM;
  37         do_color_align = 0;
  38         if (filp || (flags & MAP_SHARED))
  39                 do_color_align = 1;
  40         if (addr) {
  41                 if (do_color_align)
  42                         addr = COLOUR_ALIGN(addr, pgoff);
  43                 else
  44                         addr = PAGE_ALIGN(addr);
  45                 vmm = find_vma(current->mm, addr);
  46                 if (TASK_SIZE - len >= addr &&
  47                                 (!vmm || addr + len <= vmm->vm_start))
  48                         return addr;
  49         }
  50         addr = TASK_UNMAPPED_BASE;
  51         if (do_color_align)
  52                 addr = COLOUR_ALIGN(addr, pgoff);
  53         else
  54                 addr = PAGE_ALIGN(addr);
  55
  56         for (vmm = find_vma(current->mm, addr); ; vmm = vmm->vm_next) {
  57                 /* At this point: (!vmm || addr < vmm->vm_end). */
  58                 if (TASK_SIZE - len < addr)
  59                         return -ENOMEM;
  60                 if (!vmm || addr + len <= vmm->vm_start)
  61                         return addr;
  62                 addr = vmm->vm_end;
  63                 if (do_color_align)
  64                         addr = COLOUR_ALIGN(addr, pgoff);
  65         }
  66 }