wrapper/kallsyms.h

   1 /* SPDX-License-Identifier: (GPL-2.0 or LGPL-2.1)
   2  *
   3  * wrapper/kallsyms.h
   4  *
   5  * wrapper around kallsyms_lookup_name. Implements arch-dependent code for
   6  * arches where the address of the start of the function body is different
   7  * from the pointer which can be used to call the function, e.g. ARM THUMB2.
   8  *
   9  * Copyright (C) 2011 Avik Sil (avik.sil@linaro.org)
  10  * Copyright (C) 2011-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
  11  */
  12
  13 #ifndef _LTTNG_WRAPPER_KALLSYMS_H
  14 #define _LTTNG_WRAPPER_KALLSYMS_H
  15
  16 #include <linux/kallsyms.h>
  17 #include <linux/version.h>
  18
  19 /*
  20  * PowerPC ABIv1 needs KALLSYMS_ALL to get the function descriptor,
  21  * which is needed to perform the function call.
  22  */
  23 #if defined(CONFIG_PPC64) && (!defined(_CALL_ELF) || _CALL_ELF < 2)
  24 # ifndef CONFIG_KALLSYMS_ALL
  25 #  error "LTTng-modules requires CONFIG_KALLSYMS_ALL on PowerPC ABIv1"
  26 # endif
  27 #endif
  28
  29 #if (LINUX_VERSION_CODE >= KERNEL_VERSION(5,7,0))
  30
  31 unsigned long wrapper_kallsyms_lookup_name(const char *name);
  32
  33 #else /* #if (LINUX_VERSION_CODE >= KERNEL_VERSION(5,7,0)) */
  34
  35 static inline
  36 unsigned long wrapper_kallsyms_lookup_name(const char *name)
  37 {
  38         return kallsyms_lookup_name(name);
  39 }
  40
  41 #endif /* #else #if (LINUX_VERSION_CODE >= KERNEL_VERSION(5,7,0)) */
  42
  43 static inline
  44 unsigned long kallsyms_lookup_funcptr(const char *name)
  45 {
  46         unsigned long addr;
  47
  48         addr = wrapper_kallsyms_lookup_name(name);
  49 #ifdef CONFIG_ARM
  50 #ifdef CONFIG_THUMB2_KERNEL
  51         if (addr)
  52                 addr |= 1; /* set bit 0 in address for thumb mode */
  53 #endif
  54 #endif
  55         return addr;
  56 }
  57
  58 static inline
  59 unsigned long kallsyms_lookup_dataptr(const char *name)
  60 {
  61         return wrapper_kallsyms_lookup_name(name);
  62 }
  63
  64 #endif /* _LTTNG_WRAPPER_KALLSYMS_H */