1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef _ASM_S390_JUMP_LABEL_H 3 #define _ASM_S390_JUMP_LABEL_H 4 5 #ifndef __ASSEMBLY__ 6 7 #include <linux/types.h> 8 #include <linux/stringify.h> 9 10 #define JUMP_LABEL_NOP_SIZE 6 11 #define JUMP_LABEL_NOP_OFFSET 2 12 13 #ifdef CONFIG_CC_IS_CLANG 14 #define JUMP_LABEL_STATIC_KEY_CONSTRAINT "i" 15 #elif __GNUC__ < 9 16 #define JUMP_LABEL_STATIC_KEY_CONSTRAINT "X" 17 #else 18 #define JUMP_LABEL_STATIC_KEY_CONSTRAINT "jdd" 19 #endif 20 21 /* 22 * We use a brcl 0,2 instruction for jump labels at compile time so it 23 * can be easily distinguished from a hotpatch generated instruction. 24 */ 25 static __always_inline bool arch_static_branch(struct static_key *key, bool branch) 26 { 27 asm_volatile_goto("0: brcl 0,"__stringify(JUMP_LABEL_NOP_OFFSET)"\n" 28 ".pushsection __jump_table,\"aw\"\n" 29 ".balign 8\n" 30 ".long 0b-.,%l[label]-.\n" 31 ".quad %0+%1-.\n" 32 ".popsection\n" 33 : : JUMP_LABEL_STATIC_KEY_CONSTRAINT (key), "i" (branch) : : label); 34 return false; 35 label: 36 return true; 37 } 38 39 static __always_inline bool arch_static_branch_jump(struct static_key *key, bool branch) 40 { 41 asm_volatile_goto("0: brcl 15,%l[label]\n" 42 ".pushsection __jump_table,\"aw\"\n" 43 ".balign 8\n" 44 ".long 0b-.,%l[label]-.\n" 45 ".quad %0+%1-.\n" 46 ".popsection\n" 47 : : JUMP_LABEL_STATIC_KEY_CONSTRAINT (key), "i" (branch) : : label); 48 return false; 49 label: 50 return true; 51 } 52 53 #endif /* __ASSEMBLY__ */ 54 #endif 55