wrapper/page_alloc.c

   1 /*
   2  * wrapper/page_alloc.c
   3  *
   4  * wrapper around get_pfnblock_flags_mask and Ubuntu
   5  * get_pageblock_flags_mask. Using KALLSYMS to get their address when
   6  * available, else we need to have a kernel that exports this function
   7  * to GPL modules.
   8  *
   9  * Copyright (C) 2015 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
  10  *
  11  * This library is free software; you can redistribute it and/or
  12  * modify it under the terms of the GNU Lesser General Public
  13  * License as published by the Free Software Foundation; only
  14  * version 2.1 of the License.
  15  *
  16  * This library is distributed in the hope that it will be useful,
  17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  19  * Lesser General Public License for more details.
  20  *
  21  * You should have received a copy of the GNU Lesser General Public
  22  * License along with this library; if not, write to the Free Software
  23  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  24  */
  25
  26 #include "../lttng-kernel-version.h"
  27
  28 #if (defined(CONFIG_KALLSYMS) \
  29         && (LINUX_VERSION_CODE >= KERNEL_VERSION(3,19,2) \
  30                 || LTTNG_DEBIAN_KERNEL_RANGE(3,16,7,9,0,0, 3,17,0,0,0,0)))
  31
  32 #include <linux/kallsyms.h>
  33 #include <linux/mm_types.h>
  34 #include <linux/module.h>
  35 #include "kallsyms.h"
  36 #include "page_alloc.h"
  37
  38 static
  39 unsigned long (*get_pfnblock_flags_mask_sym)(struct page *page,
  40                 unsigned long pfn,
  41                 unsigned long end_bitidx,
  42                 unsigned long mask);
  43
  44 unsigned long wrapper_get_pfnblock_flags_mask(struct page *page,
  45                 unsigned long pfn,
  46                 unsigned long end_bitidx,
  47                 unsigned long mask)
  48 {
  49         WARN_ON_ONCE(!get_pfnblock_flags_mask_sym);
  50         if (get_pfnblock_flags_mask_sym) {
  51                 return get_pfnblock_flags_mask_sym(page, pfn, end_bitidx, mask);
  52         } else {
  53                 return -ENOSYS;
  54         }
  55 }
  56 EXPORT_SYMBOL_GPL(wrapper_get_pfnblock_flags_mask);
  57
  58 int wrapper_get_pfnblock_flags_mask_init(void)
  59 {
  60         get_pfnblock_flags_mask_sym =
  61                 (void *) kallsyms_lookup_funcptr("get_pfnblock_flags_mask");
  62         if (!get_pfnblock_flags_mask_sym)
  63                 return -1;
  64         return 0;
  65 }
  66
  67 #else
  68
  69 #include <linux/pageblock-flags.h>
  70
  71 #endif
  72
  73 #if (defined(CONFIG_KALLSYMS) \
  74         && LTTNG_UBUNTU_KERNEL_RANGE(3,13,11,50, 3,14,0,0))
  75
  76 #include <linux/kallsyms.h>
  77 #include <linux/mm_types.h>
  78 #include <linux/module.h>
  79 #include "kallsyms.h"
  80 #include "page_alloc.h"
  81
  82 static
  83 unsigned long (*get_pageblock_flags_mask_sym)(struct page *page,
  84                 unsigned long end_bitidx,
  85                 unsigned long mask);
  86
  87 unsigned long wrapper_get_pageblock_flags_mask(struct page *page,
  88                 unsigned long end_bitidx,
  89                 unsigned long mask)
  90 {
  91         WARN_ON_ONCE(!get_pageblock_flags_mask_sym);
  92         if (get_pageblock_flags_mask_sym) {
  93                 return get_pageblock_flags_mask_sym(page, end_bitidx, mask);
  94         } else {
  95                 return -ENOSYS;
  96         }
  97 }
  98 EXPORT_SYMBOL_GPL(wrapper_get_pageblock_flags_mask);
  99
 100 int wrapper_get_pageblock_flags_mask_init(void)
 101 {
 102         get_pageblock_flags_mask_sym =
 103                 (void *) kallsyms_lookup_funcptr("get_pageblock_flags_mask");
 104         if (!get_pageblock_flags_mask_sym)
 105                 return -1;
 106         return 0;
 107 }
 108
 109 #else
 110
 111 #include <linux/pageblock-flags.h>
 112
 113 #endif