From: Frederic Weisbecker frederic@kernel.org
mainline inclusion from mainline-5.12-rc1 commit 29fd01944b7273bb630c649a2104b7f9e4ef3fa6 category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/I410UT CVE: NA Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...
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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 Signed-off-by: Ma Junhai majunhai2@huawei.com Reviewed-by: Chen Hui judy.chenhui@huawei.com Signed-off-by: Zheng Zengkai zhengzengkai@huawei.com --- include/linux/static_call.h | 22 ++++++++++++++-------- 1 file changed, 14 insertions(+), 8 deletions(-)
diff --git a/include/linux/static_call.h b/include/linux/static_call.h index 6550902c8b59..85ecc789f4ff 100644 --- a/include/linux/static_call.h +++ b/include/linux/static_call.h @@ -150,13 +150,13 @@ 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); \ @@ -191,12 +191,12 @@ 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); \ @@ -252,10 +252,10 @@ 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) \ @@ -304,4 +304,10 @@ 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 */