LXR linux/include/linux/static_call

   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 */
  32struct 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
  61struct 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
  76struct 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
  94struct 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 */
 104