sysdeps/unix/sysv/linux/mmap_internal.h

   1 /* Common mmap definition for Linux implementation.
   2    Copyright (C) 2017-2019 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <https://www.gnu.org/licenses/>.  */
  18
  19 #ifndef MMAP_INTERNAL_LINUX_H
  20 #define MMAP_INTERNAL_LINUX_H 1
  21
  22 /* This is the minimum mmap2 unit size accept by the kernel.  An architecture
  23    with multiple minimum page sizes (such as m68k) might define it as -1 and
  24    thus it will queried at runtime.  */
  25 #ifndef MMAP2_PAGE_UNIT
  26 # define MMAP2_PAGE_UNIT 4096ULL
  27 #endif
  28
  29 #if MMAP2_PAGE_UNIT == -1
  30 static uint64_t page_unit;
  31 # define MMAP_CHECK_PAGE_UNIT()                 \
  32   if (page_unit == 0)                           \
  33     page_unit = __getpagesize ();
  34 # undef MMAP2_PAGE_UNIT
  35 # define MMAP2_PAGE_UNIT page_unit
  36 #else
  37 # define MMAP_CHECK_PAGE_UNIT()
  38 #endif
  39
  40 /* Do not accept offset not multiple of page size.  */
  41 #define MMAP_OFF_LOW_MASK  (MMAP2_PAGE_UNIT - 1)
  42
  43 /* An architecture may override this.  */
  44 #ifndef MMAP_CALL
  45 # define MMAP_CALL(__nr, __addr, __len, __prot, __flags, __fd, __offset) \
  46   INLINE_SYSCALL_CALL (__nr, __addr, __len, __prot, __flags, __fd, __offset)
  47 #endif
  48
  49 #endif /* MMAP_INTERNAL_LINUX_H  */