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) && (LINUX_VERSION_CODE >= KERNEL_VERSION(3,19,2))
  29
  30 #include <linux/kallsyms.h>
  31 #include <linux/mm_types.h>
  32 #include <linux/module.h>
  33 #include "kallsyms.h"
  34 #include "page_alloc.h"
  35
  36 static
  37 unsigned long (*get_pfnblock_flags_mask_sym)(struct page *page,
  38                 unsigned long pfn,
  39                 unsigned long end_bitidx,
  40                 unsigned long mask);
  41
  42 unsigned long wrapper_get_pfnblock_flags_mask(struct page *page,
  43                 unsigned long pfn,
  44                 unsigned long end_bitidx,
  45                 unsigned long mask)
  46 {
  47         WARN_ON_ONCE(!get_pfnblock_flags_mask_sym);
  48         if (get_pfnblock_flags_mask_sym) {
  49                 return get_pfnblock_flags_mask_sym(page, pfn, end_bitidx, mask);
  50         } else {
  51                 return -ENOSYS;
  52         }
  53 }
  54 EXPORT_SYMBOL_GPL(wrapper_get_pfnblock_flags_mask);
  55
  56 int wrapper_get_pfnblock_flags_mask_init(void)
  57 {
  58         get_pfnblock_flags_mask_sym =
  59                 (void *) kallsyms_lookup_funcptr("get_pfnblock_flags_mask");
  60         if (!get_pfnblock_flags_mask_sym)
  61                 return -1;
  62         return 0;
  63 }
  64
  65 #else
  66
  67 #include <linux/pageblock-flags.h>
  68
  69 #endif
  70
  71 #if (defined(CONFIG_KALLSYMS) \
  72         && LTTNG_UBUNTU_KERNEL_RANGE(3,13,11,50, 3,14,0,0))
  73
  74 #include <linux/kallsyms.h>
  75 #include <linux/mm_types.h>
  76 #include <linux/module.h>
  77 #include "kallsyms.h"
  78 #include "page_alloc.h"
  79
  80 static
  81 unsigned long (*get_pageblock_flags_mask_sym)(struct page *page,
  82                 unsigned long end_bitidx,
  83                 unsigned long mask);
  84
  85 unsigned long wrapper_get_pageblock_flags_mask(struct page *page,
  86                 unsigned long end_bitidx,
  87                 unsigned long mask)
  88 {
  89         WARN_ON_ONCE(!get_pageblock_flags_mask_sym);
  90         if (get_pageblock_flags_mask_sym) {
  91                 return get_pageblock_flags_mask_sym(page, end_bitidx, mask);
  92         } else {
  93                 return -ENOSYS;
  94         }
  95 }
  96 EXPORT_SYMBOL_GPL(wrapper_get_pageblock_flags_mask);
  97
  98 int wrapper_get_pageblock_flags_mask_init(void)
  99 {
 100         get_pageblock_flags_mask_sym =
 101                 (void *) kallsyms_lookup_funcptr("get_pageblock_flags_mask");
 102         if (!get_pageblock_flags_mask_sym)
 103                 return -1;
 104         return 0;
 105 }
 106
 107 #else
 108
 109 #include <linux/pageblock-flags.h>
 110
 111 #endif