src/wrapper/irqdesc.c

   1 /* SPDX-License-Identifier: (GPL-2.0-only OR LGPL-2.1-only)
   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 and removed in 5.11.
   8  *
   9  * Copyright (C) 2011-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
  10  */
  11
  12 #include <lttng/kernel-version.h>
  13 #include <linux/module.h>
  14
  15 #if (defined(CONFIG_KALLSYMS) && \
  16         (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(5,11,0)))
  17
  18 #include <linux/kallsyms.h>
  19 #include <linux/interrupt.h>
  20 #include <linux/irqnr.h>
  21 #include <wrapper/kallsyms.h>
  22 #include <wrapper/irqdesc.h>
  23
  24 static
  25 struct irq_desc *(*irq_to_desc_sym)(unsigned int irq);
  26
  27 struct irq_desc *wrapper_irq_to_desc(unsigned int irq)
  28 {
  29         if (!irq_to_desc_sym)
  30                 irq_to_desc_sym = (void *) kallsyms_lookup_funcptr("irq_to_desc");
  31         if (irq_to_desc_sym) {
  32                 struct irq_ibt_state irq_ibt_state;
  33                 struct irq_desc *ret;
  34
  35                 irq_ibt_state = wrapper_irq_ibt_save();
  36                 ret = irq_to_desc_sym(irq);
  37                 wrapper_irq_ibt_restore(irq_ibt_state);
  38                 return ret;
  39         } else {
  40                 printk_once(KERN_WARNING "LTTng: irq_to_desc symbol lookup failed.\n");
  41                 return NULL;
  42         }
  43 }
  44 EXPORT_SYMBOL_GPL(wrapper_irq_to_desc);
  45
  46 #else
  47
  48 #include <linux/interrupt.h>
  49 #include <linux/irqnr.h>
  50
  51 struct irq_desc *wrapper_irq_to_desc(unsigned int irq)
  52 {
  53         return irq_to_desc(irq);
  54 }
  55 EXPORT_SYMBOL_GPL(wrapper_irq_to_desc);
  56
  57 #endif