wrapper/vmalloc.h

   1 #ifndef _LTTNG_WRAPPER_VMALLOC_H
   2 #define _LTTNG_WRAPPER_VMALLOC_H
   3
   4 /*
   5  * wrapper/vmalloc.h
   6  *
   7  * wrapper around vmalloc_sync_all. Using KALLSYMS to get its address when
   8  * available, else we need to have a kernel that exports this function to GPL
   9  * modules.
  10  *
  11  * Copyright (C) 2011-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
  12  *
  13  * This library is free software; you can redistribute it and/or
  14  * modify it under the terms of the GNU Lesser General Public
  15  * License as published by the Free Software Foundation; only
  16  * version 2.1 of the License.
  17  *
  18  * This library is distributed in the hope that it will be useful,
  19  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  20  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  21  * Lesser General Public License for more details.
  22  *
  23  * You should have received a copy of the GNU Lesser General Public
  24  * License along with this library; if not, write to the Free Software
  25  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  26  */
  27
  28 #ifdef CONFIG_KALLSYMS
  29
  30 #include <linux/kallsyms.h>
  31 #include <wrapper/kallsyms.h>
  32
  33 static inline
  34 void wrapper_vmalloc_sync_all(void)
  35 {
  36         void (*vmalloc_sync_all_sym)(void);
  37
  38         vmalloc_sync_all_sym = (void *) kallsyms_lookup_funcptr("vmalloc_sync_all");
  39         if (vmalloc_sync_all_sym) {
  40                 vmalloc_sync_all_sym();
  41         } else {
  42 #ifdef CONFIG_X86
  43                 /*
  44                  * Only x86 needs vmalloc_sync_all to make sure LTTng does not
  45                  * trigger recursive page faults.
  46                  */
  47                 printk_once(KERN_WARNING "LTTng: vmalloc_sync_all symbol lookup failed.\n");
  48                 printk_once(KERN_WARNING "Page fault handler and NMI tracing might trigger faults.\n");
  49 #endif
  50         }
  51 }
  52 #else
  53
  54 #include <linux/vmalloc.h>
  55
  56 static inline
  57 void wrapper_vmalloc_sync_all(void)
  58 {
  59         return vmalloc_sync_all();
  60 }
  61 #endif
  62
  63 #endif /* _LTTNG_WRAPPER_VMALLOC_H */