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