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kernel/linux-rt-4.4.41/arch/s390/include/asm/jump_label.h 1.13 KB
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  #ifndef _ASM_S390_JUMP_LABEL_H
  #define _ASM_S390_JUMP_LABEL_H
  
  #ifndef __ASSEMBLY__
  
  #include <linux/types.h>
  
  #define JUMP_LABEL_NOP_SIZE 6
  #define JUMP_LABEL_NOP_OFFSET 2
  
  /*
   * We use a brcl 0,2 instruction for jump labels at compile time so it
   * can be easily distinguished from a hotpatch generated instruction.
   */
  static __always_inline bool arch_static_branch(struct static_key *key, bool branch)
  {
  	asm_volatile_goto("0:	brcl 0,"__stringify(JUMP_LABEL_NOP_OFFSET)"
  "
  		".pushsection __jump_table, \"aw\"
  "
  		".balign 8
  "
  		".quad 0b, %l[label], %0
  "
  		".popsection
  "
  		: : "X" (&((char *)key)[branch]) : : label);
  
  	return false;
  label:
  	return true;
  }
  
  static __always_inline bool arch_static_branch_jump(struct static_key *key, bool branch)
  {
  	asm_volatile_goto("0:	brcl 15, %l[label]
  "
  		".pushsection __jump_table, \"aw\"
  "
  		".balign 8
  "
  		".quad 0b, %l[label], %0
  "
  		".popsection
  "
  		: : "X" (&((char *)key)[branch]) : : label);
  
  	return false;
  label:
  	return true;
  }
  
  typedef unsigned long jump_label_t;
  
  struct jump_entry {
  	jump_label_t code;
  	jump_label_t target;
  	jump_label_t key;
  };
  
  #endif  /* __ASSEMBLY__ */
  #endif