wrapper/irqdesc.c

   1 /* SPDX-License-Identifier: (GPL-2.0 OR LGPL-2.1)
   2  *
   3  * wrapper/irqdesc.c
   4  *
   5  * wrapper around irq_to_desc. Using KALLSYMS to get its address when
   6  * available, else we need to have a kernel that exports this function to GPL
   7  * modules. This export was added to the 3.4 kernels.
   8  *
   9  * Copyright (C) 2011-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
  10  */
  11
  12 #include <lttng-kernel-version.h>
  13
  14 #if (defined(CONFIG_KALLSYMS) \
  15         && (LINUX_VERSION_CODE < KERNEL_VERSION(3,4,0)))
  16
  17 #include <linux/kallsyms.h>
  18 #include <linux/interrupt.h>
  19 #include <linux/irqnr.h>
  20 #include <wrapper/kallsyms.h>
  21 #include <wrapper/irqdesc.h>
  22
  23 static
  24 struct irq_desc *(*irq_to_desc_sym)(unsigned int irq);
  25
  26 struct irq_desc *wrapper_irq_to_desc(unsigned int irq)
  27 {
  28         if (!irq_to_desc_sym)
  29                 irq_to_desc_sym = (void *) kallsyms_lookup_funcptr("irq_to_desc");
  30         if (irq_to_desc_sym) {
  31                 return irq_to_desc_sym(irq);
  32         } else {
  33                 printk_once(KERN_WARNING "LTTng: irq_to_desc symbol lookup failed.\n");
  34                 return NULL;
  35         }
  36 }
  37
  38 #else
  39
  40 #include <linux/interrupt.h>
  41 #include <linux/irqnr.h>
  42
  43 struct irq_desc *wrapper_irq_to_desc(unsigned int irq)
  44 {
  45         return irq_to_desc(irq);
  46 }
  47
  48 #endif