include/wrapper/kallsyms.h

   1 /* SPDX-License-Identifier: (GPL-2.0-only or LGPL-2.1-only)
   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 <lttng/kernel-version.h>
  18
  19 #include <wrapper/ibt.h>
  20
  21 /* CONFIG_PPC64_ELF_ABI_V1/V2 were introduced in v5.19 */
  22 #if defined(CONFIG_PPC64_ELF_ABI_V2) || (defined(CONFIG_PPC64) && defined(CONFIG_CPU_LITTLE_ENDIAN))
  23 #define LTTNG_CONFIG_PPC64_ELF_ABI_V2
  24 #endif
  25 #if defined(CONFIG_PPC64_ELF_ABI_V1) || (defined(CONFIG_PPC64) && defined(CONFIG_CPU_BIG_ENDIAN))
  26 #define LTTNG_CONFIG_PPC64_ELF_ABI_V1
  27 #endif
  28
  29 /*
  30  * PowerPC ABIv1 needs KALLSYMS_ALL to get the function descriptor,
  31  * which is needed to perform the function call.
  32  */
  33 #ifdef LTTNG_CONFIG_PPC64_ELF_ABI_V1
  34 # ifndef CONFIG_KALLSYMS_ALL
  35 #  error "LTTng-modules requires CONFIG_KALLSYMS_ALL on PowerPC ABIv1"
  36 # endif
  37 #endif
  38
  39 #if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(5,7,0))
  40
  41 unsigned long wrapper_kallsyms_lookup_name(const char *name);
  42
  43 #else /* #if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(5,7,0)) */
  44
  45 static inline
  46 unsigned long wrapper_kallsyms_lookup_name(const char *name)
  47 {
  48         return kallsyms_lookup_name(name);
  49 }
  50
  51 #endif /* #else #if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(5,7,0)) */
  52
  53 static inline
  54 unsigned long kallsyms_lookup_funcptr(const char *name)
  55 {
  56         unsigned long addr;
  57
  58         addr = wrapper_kallsyms_lookup_name(name);
  59 #if defined(CONFIG_ARM) && defined(CONFIG_THUMB2_KERNEL)
  60         if (addr)
  61                 addr |= 1; /* set bit 0 in address for thumb mode */
  62 #endif
  63         return addr;
  64 }
  65
  66 static inline
  67 unsigned long kallsyms_lookup_dataptr(const char *name)
  68 {
  69         return wrapper_kallsyms_lookup_name(name);
  70 }
  71
  72 #endif /* _LTTNG_WRAPPER_KALLSYMS_H */