1. 根目录:
2. arch
3. arm
4. include
5. asm
6. jump_label.h

#ifndef _ASM_ARM_JUMP_LABEL_H
#define _ASM_ARM_JUMP_LABEL_H

#ifdef __KERNEL__

#include <linux/types.h>
#include <asm/system.h>

#define JUMP_LABEL_NOP_SIZE 4

#ifdef CONFIG_THUMB2_KERNEL
#define JUMP_LABEL_NOP	"nop.w"
#else
#define JUMP_LABEL_NOP	"nop"
#endif

static __always_inline bool arch_static_branch(struct static_key *key)
{
	asm goto("1:\n\t"
		 JUMP_LABEL_NOP "\n\t"
		 ".pushsection __jump_table,  \"aw\"\n\t"
		 ".word 1b, %l[l_yes], %c0\n\t"
		 ".popsection\n\t"
		 : :  "i" (key) :  : l_yes);

	return false;
l_yes:
	return true;
}

#endif /* __KERNEL__ */

typedef u32 jump_label_t;

struct jump_entry {
	jump_label_t code;
	jump_label_t target;
	jump_label_t key;
};

#endif