Linux Kernel  3.7.1
 All Data Structures Namespaces Files Functions Variables Typedefs Enumerations Enumerator Macros Groups Pages
jump_label.h
Go to the documentation of this file.
1 #ifndef _ASM_X86_JUMP_LABEL_H
2 #define _ASM_X86_JUMP_LABEL_H
3 
4 #ifdef __KERNEL__
5 
6 #include <linux/types.h>
7 #include <asm/nops.h>
8 #include <asm/asm.h>
9 
10 #define JUMP_LABEL_NOP_SIZE 5
11 
12 #define STATIC_KEY_INITIAL_NOP ".byte 0xe9 \n\t .long 0\n\t"
13 
14 static __always_inline bool arch_static_branch(struct static_key *key)
15 {
16  asm goto("1:"
17  STATIC_KEY_INITIAL_NOP
18  ".pushsection __jump_table, \"aw\" \n\t"
19  _ASM_ALIGN "\n\t"
20  _ASM_PTR "1b, %l[l_yes], %c0 \n\t"
21  ".popsection \n\t"
22  : : "i" (key) : : l_yes);
23  return false;
24 l_yes:
25  return true;
26 }
27 
28 #endif /* __KERNEL__ */
29 
30 #ifdef CONFIG_X86_64
31 typedef u64 jump_label_t;
32 #else
33 typedef u32 jump_label_t;
34 #endif
35 
36 struct jump_entry {
37  jump_label_t code;
38  jump_label_t target;
39  jump_label_t key;
40 };
41 
42 #endif