include/linux/static_call_types.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef _STATIC_CALL_TYPES_H
   3 #define _STATIC_CALL_TYPES_H
   4
   5 #include <linux/types.h>
   6 #include <linux/stringify.h>
   7 #include <linux/compiler.h>
   8
   9 #define STATIC_CALL_KEY_PREFIX          __SCK__
  10 #define STATIC_CALL_KEY_PREFIX_STR      __stringify(STATIC_CALL_KEY_PREFIX)
  11 #define STATIC_CALL_KEY_PREFIX_LEN      (sizeof(STATIC_CALL_KEY_PREFIX_STR) - 1)
  12 #define STATIC_CALL_KEY(name)           __PASTE(STATIC_CALL_KEY_PREFIX, name)
  13 #define STATIC_CALL_KEY_STR(name)       __stringify(STATIC_CALL_KEY(name))
  14
  15 #define STATIC_CALL_TRAMP_PREFIX        __SCT__
  16 #define STATIC_CALL_TRAMP_PREFIX_STR    __stringify(STATIC_CALL_TRAMP_PREFIX)
  17 #define STATIC_CALL_TRAMP_PREFIX_LEN    (sizeof(STATIC_CALL_TRAMP_PREFIX_STR) - 1)
  18 #define STATIC_CALL_TRAMP(name)         __PASTE(STATIC_CALL_TRAMP_PREFIX, name)
  19 #define STATIC_CALL_TRAMP_STR(name)     __stringify(STATIC_CALL_TRAMP(name))
  20
  21 /*
  22  * Flags in the low bits of static_call_site::key.
  23  */
  24 #define STATIC_CALL_SITE_TAIL 1UL       /* tail call */
  25 #define STATIC_CALL_SITE_INIT 2UL       /* init section */
  26 #define STATIC_CALL_SITE_FLAGS 3UL
  27
  28 /*
  29  * The static call site table needs to be created by external tooling (objtool
  30  * or a compiler plugin).
  31  */
  32 struct static_call_site {
  33         s32 addr;
  34         s32 key;
  35 };
  36
  37 #define DECLARE_STATIC_CALL(name, func)                                 \
  38         extern struct static_call_key STATIC_CALL_KEY(name);            \
  39         extern typeof(func) STATIC_CALL_TRAMP(name);
  40
  41 #ifdef CONFIG_HAVE_STATIC_CALL
  42
  43 #define __raw_static_call(name) (&STATIC_CALL_TRAMP(name))
  44
  45 #ifdef CONFIG_HAVE_STATIC_CALL_INLINE
  46
  47 /*
  48  * __ADDRESSABLE() is used to ensure the key symbol doesn't get stripped from
  49  * the symbol table so that objtool can reference it when it generates the
  50  * .static_call_sites section.
  51  */
  52 #define __STATIC_CALL_ADDRESSABLE(name) \
  53         __ADDRESSABLE(STATIC_CALL_KEY(name))
  54
  55 #define __static_call(name)                                             \
  56 ({                                                                      \
  57         __STATIC_CALL_ADDRESSABLE(name);                                \
  58         __raw_static_call(name);                                        \
  59 })
  60
  61 struct static_call_key {
  62         void *func;
  63         union {
  64                 /* bit 0: 0 = mods, 1 = sites */
  65                 unsigned long type;
  66                 struct static_call_mod *mods;
  67                 struct static_call_site *sites;
  68         };
  69 };
  70
  71 #else /* !CONFIG_HAVE_STATIC_CALL_INLINE */
  72
  73 #define __STATIC_CALL_ADDRESSABLE(name)
  74 #define __static_call(name)     __raw_static_call(name)
  75
  76 struct static_call_key {
  77         void *func;
  78 };
  79
  80 #endif /* CONFIG_HAVE_STATIC_CALL_INLINE */
  81
  82 #ifdef MODULE
  83 #define __STATIC_CALL_MOD_ADDRESSABLE(name)
  84 #define static_call_mod(name)   __raw_static_call(name)
  85 #else
  86 #define __STATIC_CALL_MOD_ADDRESSABLE(name) __STATIC_CALL_ADDRESSABLE(name)
  87 #define static_call_mod(name)   __static_call(name)
  88 #endif
  89
  90 #define static_call(name)       __static_call(name)
  91
  92 #else
  93
  94 struct static_call_key {
  95         void *func;
  96 };
  97
  98 #define static_call(name)                                               \
  99         ((typeof(STATIC_CALL_TRAMP(name))*)(STATIC_CALL_KEY(name).func))
 100
 101 #endif /* CONFIG_HAVE_STATIC_CALL */
 102
 103 #endif /* _STATIC_CALL_TYPES_H */