From a945c8345ec0decb2f1a7f19a8c5e60bcb1dd1eb Mon Sep 17 00:00:00 2001
From: Peter Zijlstra <peterz@infradead.org>
Date: Tue, 18 Aug 2020 15:57:51 +0200
Subject: static_call: Allow early init
In order to use static_call() to wire up x86_pmu, we need to
initialize earlier, specifically before memory allocation works; copy
some of the tricks from jump_label to enable this.
Primarily we overload key->next to store a sites pointer when there
are no modules, this avoids having to use kmalloc() to initialize the
sites and allows us to run much earlier.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Link: https://lore.kernel.org/r/20200818135805.220737930@infradead.org
---
include/linux/static_call.h | 15 +++++++++++++--
1 file changed, 13 insertions(+), 2 deletions(-)
(limited to 'include/linux/static_call.h')
diff --git a/include/linux/static_call.h b/include/linux/static_call.h
index 519bd666e096..bfa2ba39be57 100644
--- a/include/linux/static_call.h
+++ b/include/linux/static_call.h
@@ -136,6 +136,8 @@ extern void arch_static_call_transform(void *site, void *tramp, void *func, bool
#ifdef CONFIG_HAVE_STATIC_CALL_INLINE
+extern void __init static_call_init(void);
+
struct static_call_mod {
struct static_call_mod *next;
struct module *mod; /* for vmlinux, mod == NULL */
@@ -144,7 +146,12 @@ struct static_call_mod {
struct static_call_key {
void *func;
- struct static_call_mod *mods;
+ union {
+ /* bit 0: 0 = mods, 1 = sites */
+ unsigned long type;
+ struct static_call_mod *mods;
+ struct static_call_site *sites;
+ };
};
extern void __static_call_update(struct static_call_key *key, void *tramp, void *func);
@@ -155,7 +162,7 @@ extern int static_call_text_reserved(void *start, void *end);
DECLARE_STATIC_CALL(name, _func); \
struct static_call_key STATIC_CALL_KEY(name) = { \
.func = _func, \
- .mods = NULL, \
+ .type = 1, \
}; \
ARCH_DEFINE_STATIC_CALL_TRAMP(name, _func)
@@ -180,6 +187,8 @@ extern int static_call_text_reserved(void *start, void *end);
#elif defined(CONFIG_HAVE_STATIC_CALL)
+static inline void static_call_init(void) { }
+
struct static_call_key {
void *func;
};
@@ -225,6 +234,8 @@ static inline int static_call_text_reserved(void *start, void *end)
#else /* Generic implementation */
+static inline void static_call_init(void) { }
+
struct static_call_key {
void *func;
};
--
cgit