wrapper/irqdesc.c

   1 /*
   2  * wrapper/irqdesc.c
   3  *
   4  * wrapper around irq_to_desc. Using KALLSYMS to get its address when
   5  * available, else we need to have a kernel that exports this function to GPL
   6  * modules. This export was added to the 3.4 kernels.
   7  *
   8  * Copyright (C) 2011-2012 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         && (LTTNG_LINUX_VERSION_CODE < LTTNG_KERNEL_VERSION(3,4,0)))
  29
  30 #include <linux/kallsyms.h>
  31 #include <linux/interrupt.h>
  32 #include <linux/irqnr.h>
  33 #include <wrapper/kallsyms.h>
  34 #include <wrapper/irqdesc.h>
  35
  36 static
  37 struct irq_desc *(*irq_to_desc_sym)(unsigned int irq);
  38
  39 struct irq_desc *wrapper_irq_to_desc(unsigned int irq)
  40 {
  41         if (!irq_to_desc_sym)
  42                 irq_to_desc_sym = (void *) kallsyms_lookup_funcptr("irq_to_desc");
  43         if (irq_to_desc_sym) {
  44                 return irq_to_desc_sym(irq);
  45         } else {
  46                 printk_once(KERN_WARNING "LTTng: irq_to_desc symbol lookup failed.\n");
  47                 return NULL;
  48         }
  49 }
  50
  51 #else
  52
  53 #include <linux/interrupt.h>
  54 #include <linux/irqnr.h>
  55
  56 struct irq_desc *wrapper_irq_to_desc(unsigned int irq)
  57 {
  58         return irq_to_desc(irq);
  59 }
  60
  61 #endif