diff options
Diffstat (limited to 'include/linux/jump_label.h')
| -rw-r--r-- | include/linux/jump_label.h | 34 |
1 files changed, 24 insertions, 10 deletions
diff --git a/include/linux/jump_label.h b/include/linux/jump_label.h index b63d6b7b0db0..2afd74b9d844 100644 --- a/include/linux/jump_label.h +++ b/include/linux/jump_label.h @@ -89,11 +89,24 @@ extern bool static_key_initialized; struct static_key { atomic_t enabled; -/* Set lsb bit to 1 if branch is default true, 0 ot */ - struct jump_entry *entries; -#ifdef CONFIG_MODULES - struct static_key_mod *next; -#endif +/* + * Note: + * To make anonymous unions work with old compilers, the static + * initialization of them requires brackets. This creates a dependency + * on the order of the struct with the initializers. If any fields + * are added, STATIC_KEY_INIT_TRUE and STATIC_KEY_INIT_FALSE may need + * to be modified. + * + * bit 0 => 1 if key is initially true + * 0 if initially false + * bit 1 => 1 if points to struct static_key_mod + * 0 if points to struct jump_entry + */ + union { + unsigned long type; + struct jump_entry *entries; + struct static_key_mod *next; + }; }; #else @@ -118,9 +131,10 @@ struct module; #ifdef HAVE_JUMP_LABEL -#define JUMP_TYPE_FALSE 0UL -#define JUMP_TYPE_TRUE 1UL -#define JUMP_TYPE_MASK 1UL +#define JUMP_TYPE_FALSE 0UL +#define JUMP_TYPE_TRUE 1UL +#define JUMP_TYPE_LINKED 2UL +#define JUMP_TYPE_MASK 3UL static __always_inline bool static_key_false(struct static_key *key) { @@ -159,10 +173,10 @@ extern void static_key_disable(struct static_key *key); */ #define STATIC_KEY_INIT_TRUE \ { .enabled = { 1 }, \ - .entries = (void *)JUMP_TYPE_TRUE } + { .entries = (void *)JUMP_TYPE_TRUE } } #define STATIC_KEY_INIT_FALSE \ { .enabled = { 0 }, \ - .entries = (void *)JUMP_TYPE_FALSE } + { .entries = (void *)JUMP_TYPE_FALSE } } #else /* !HAVE_JUMP_LABEL */ |