1 #ifndef _ASM_S390_JUMP_LABEL_H 2 #define _ASM_S390_JUMP_LABEL_H 3 4 #include <linux/types.h> 5 6 #define JUMP_LABEL_NOP_SIZE 6 7 #define JUMP_LABEL_NOP_OFFSET 2 8 9 #ifdef CONFIG_64BIT 10 #define ASM_PTR ".quad" 11 #define ASM_ALIGN ".balign 8" 12 #else 13 #define ASM_PTR ".long" 14 #define ASM_ALIGN ".balign 4" 15 #endif 16 17 /* 18 * We use a brcl 0,2 instruction for jump labels at compile time so it 19 * can be easily distinguished from a hotpatch generated instruction. 20 */ 21 static __always_inline bool arch_static_branch(struct static_key *key) 22 { 23 asm_volatile_goto("0: brcl 0,"__stringify(JUMP_LABEL_NOP_OFFSET)"\n" 24 ".pushsection __jump_table, \"aw\"\n" 25 ASM_ALIGN "\n" 26 ASM_PTR " 0b, %l[label], %0\n" 27 ".popsection\n" 28 : : "X" (key) : : label); 29 return false; 30 label: 31 return true; 32 } 33 34 typedef unsigned long jump_label_t; 35 36 struct jump_entry { 37 jump_label_t code; 38 jump_label_t target; 39 jump_label_t key; 40 }; 41 42 #endif 43