wrapper/page_alloc.c

   1 /*
   2  * wrapper/page_alloc.c
   3  *
   4  * wrapper around get_pfnblock_flags_mask. Using KALLSYMS to get its address
   5  * when available, else we need to have a kernel that exports this function to
   6  * GPL modules.
   7  *
   8  * Copyright (C) 2015 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   9  *
  10  * This library is free software; you can redistribute it and/or
  11  * modify it under the terms of the GNU Lesser General Public
  12  * License as published by the Free Software Foundation; only
  13  * version 2.1 of the License.
  14  *
  15  * This library is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  18  * Lesser General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU Lesser General Public
  21  * License along with this library; if not, write to the Free Software
  22  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  23  */
  24
  25 #include "../lttng-kernel-version.h"
  26
  27 #if (defined(CONFIG_KALLSYMS) \
  28         && (LINUX_VERSION_CODE >= KERNEL_VERSION(3,19,2) \
  29                 || LTTNG_DEBIAN_KERNEL_RANGE(3,16,7,9,0,0, 3,17,0,0,0,0)))
  30
  31 #include <linux/kallsyms.h>
  32 #include <linux/mm_types.h>
  33 #include <linux/module.h>
  34 #include "kallsyms.h"
  35 #include "page_alloc.h"
  36
  37 static
  38 unsigned long (*get_pfnblock_flags_mask_sym)(struct page *page,
  39                 unsigned long pfn,
  40                 unsigned long end_bitidx,
  41                 unsigned long mask);
  42
  43 unsigned long wrapper_get_pfnblock_flags_mask(struct page *page,
  44                 unsigned long pfn,
  45                 unsigned long end_bitidx,
  46                 unsigned long mask)
  47 {
  48         WARN_ON_ONCE(!get_pfnblock_flags_mask_sym);
  49         if (get_pfnblock_flags_mask_sym) {
  50                 return get_pfnblock_flags_mask_sym(page, pfn, end_bitidx, mask);
  51         } else {
  52                 return -ENOSYS;
  53         }
  54 }
  55 EXPORT_SYMBOL_GPL(wrapper_get_pfnblock_flags_mask);
  56
  57 int wrapper_get_pfnblock_flags_mask_init(void)
  58 {
  59         get_pfnblock_flags_mask_sym =
  60                 (void *) kallsyms_lookup_funcptr("get_pfnblock_flags_mask");
  61         if (!get_pfnblock_flags_mask_sym)
  62                 return -1;
  63         return 0;
  64 }
  65
  66 #else /* #if defined(CONFIG_KALLSYMS) && (LINUX_VERSION_CODE >= KERNEL_VERSION(3,19,2)) */
  67
  68 #include <linux/pageblock-flags.h>
  69
  70 #endif /* #else #if defined(CONFIG_KALLSYMS) && (LINUX_VERSION_CODE >= KERNEL_VERSION(3,19,2)) */