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#ifndef __ASSEMBLY__
 29
 30/*
 31 * The static call site table needs to be created by external tooling (objtool
 32 * or a compiler plugin).
 33 */
 34struct static_call_site {
 35	s32 addr;
 36	s32 key;
 37};
 38
 39#define DECLARE_STATIC_CALL(name, func)					\
 40	extern struct static_call_key STATIC_CALL_KEY(name);		\
 41	extern typeof(func) STATIC_CALL_TRAMP(name);
 42
 43#ifdef CONFIG_HAVE_STATIC_CALL
 44
 45#define __raw_static_call(name)	(&STATIC_CALL_TRAMP(name))
 46
 47#ifdef CONFIG_HAVE_STATIC_CALL_INLINE
 48
 49/*
 50 * __ADDRESSABLE() is used to ensure the key symbol doesn't get stripped from
 51 * the symbol table so that objtool can reference it when it generates the
 52 * .static_call_sites section.
 53 */
 54#define __STATIC_CALL_ADDRESSABLE(name) \
 55	__ADDRESSABLE(STATIC_CALL_KEY(name))
 56
 57#define __static_call(name)						\
 58({									\
 59	__STATIC_CALL_ADDRESSABLE(name);				\
 60	__raw_static_call(name);					\
 61})
 62
 63struct static_call_key {
 64	void *func;
 65	union {
 66		/* bit 0: 0 = mods, 1 = sites */
 67		unsigned long type;
 68		struct static_call_mod *mods;
 69		struct static_call_site *sites;
 70	};
 71};
 72
 73#else /* !CONFIG_HAVE_STATIC_CALL_INLINE */
 74
 75#define __STATIC_CALL_ADDRESSABLE(name)
 76#define __static_call(name)	__raw_static_call(name)
 77
 78struct static_call_key {
 79	void *func;
 80};
 81
 82#endif /* CONFIG_HAVE_STATIC_CALL_INLINE */
 83
 84#ifdef MODULE
 85#define __STATIC_CALL_MOD_ADDRESSABLE(name)
 86#define static_call_mod(name)	__raw_static_call(name)
 87#else
 88#define __STATIC_CALL_MOD_ADDRESSABLE(name) __STATIC_CALL_ADDRESSABLE(name)
 89#define static_call_mod(name)	__static_call(name)
 90#endif
 91
 92#define static_call(name)	__static_call(name)
 93
 94#else
 95
 96struct static_call_key {
 97	void *func;
 98};
 99
100#define static_call(name)						\
101	((typeof(STATIC_CALL_TRAMP(name))*)(STATIC_CALL_KEY(name).func))
102
103#endif /* CONFIG_HAVE_STATIC_CALL */
104
105#endif /* __ASSEMBLY__ */
106
107#endif /* _STATIC_CALL_TYPES_H */