static_call: Provide DEFINE_STATIC_CALL_RET0()

DECLARE_STATIC_CALL() must pass the original function targeted for a
given static call. But DEFINE_STATIC_CALL() may want to initialize it as
off. In this case we can't pass NULL (for functions without return value)
or __static_call_return0 (for functions returning a value) directly
to DEFINE_STATIC_CALL() as that may trigger a static call redeclaration
with a different function prototype. Type casts neither can work around
that as they don't get along with typeof().

The proper way to do that for functions that don't return a value is
to use DEFINE_STATIC_CALL_NULL(). But functions returning a actual value
don't have an equivalent yet.

Provide DEFINE_STATIC_CALL_RET0() to solve this situation.

Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lkml.kernel.org/r/20210118141223.123667-3-frederic@kernel.org
This commit is contained in:
Frederic Weisbecker 2021-01-18 15:12:17 +01:00 committed by Ingo Molnar
parent 3f2a8fc4b1
commit 29fd01944b

View file

@ -144,13 +144,13 @@ extern int static_call_text_reserved(void *start, void *end);
extern long __static_call_return0(void);
#define DEFINE_STATIC_CALL(name, _func) \
#define __DEFINE_STATIC_CALL(name, _func, _func_init) \
DECLARE_STATIC_CALL(name, _func); \
struct static_call_key STATIC_CALL_KEY(name) = { \
.func = _func, \
.func = _func_init, \
.type = 1, \
}; \
ARCH_DEFINE_STATIC_CALL_TRAMP(name, _func)
ARCH_DEFINE_STATIC_CALL_TRAMP(name, _func_init)
#define DEFINE_STATIC_CALL_NULL(name, _func) \
DECLARE_STATIC_CALL(name, _func); \
@ -178,12 +178,12 @@ struct static_call_key {
void *func;
};
#define DEFINE_STATIC_CALL(name, _func) \
#define __DEFINE_STATIC_CALL(name, _func, _func_init) \
DECLARE_STATIC_CALL(name, _func); \
struct static_call_key STATIC_CALL_KEY(name) = { \
.func = _func, \
.func = _func_init, \
}; \
ARCH_DEFINE_STATIC_CALL_TRAMP(name, _func)
ARCH_DEFINE_STATIC_CALL_TRAMP(name, _func_init)
#define DEFINE_STATIC_CALL_NULL(name, _func) \
DECLARE_STATIC_CALL(name, _func); \
@ -234,10 +234,10 @@ static inline long __static_call_return0(void)
return 0;
}
#define DEFINE_STATIC_CALL(name, _func) \
#define __DEFINE_STATIC_CALL(name, _func, _func_init) \
DECLARE_STATIC_CALL(name, _func); \
struct static_call_key STATIC_CALL_KEY(name) = { \
.func = _func, \
.func = _func_init, \
}
#define DEFINE_STATIC_CALL_NULL(name, _func) \
@ -286,4 +286,10 @@ static inline int static_call_text_reserved(void *start, void *end)
#endif /* CONFIG_HAVE_STATIC_CALL */
#define DEFINE_STATIC_CALL(name, _func) \
__DEFINE_STATIC_CALL(name, _func, _func)
#define DEFINE_STATIC_CALL_RET0(name, _func) \
__DEFINE_STATIC_CALL(name, _func, __static_call_return0)
#endif /* _LINUX_STATIC_CALL_H */