1 /* SPDX-License-Identifier: GPL-2.0-only */ 2 /* 3 * Copyright (C) 2013 Huawei Ltd. 4 * Author: Jiang Liu <liuj97@gmail.com> 5 * 6 * Based on arch/arm/include/asm/jump_label.h 7 */ 8 #ifndef __ASM_JUMP_LABEL_H 9 #define __ASM_JUMP_LABEL_H 10 11 #ifndef __ASSEMBLY__ 12 13 #include <linux/types.h> 14 #include <asm/insn.h> 15 16 #define JUMP_LABEL_NOP_SIZE AARCH64_INSN_SIZE 17 18 /* 19 * Prefer the constraint "S" to support PIC with GCC. Clang before 19 does not 20 * support "S" on a symbol with a constant offset, so we use "i" as a fallback. 21 */ 22 static __always_inline bool arch_static_branch(struct static_key * const key, 23 const bool branch) 24 { 25 asm_volatile_goto( 26 "1: nop \n\t" 27 " .pushsection __jump_table, \"aw\" \n\t" 28 " .align 3 \n\t" 29 " .long 1b - ., %l[l_yes] - . \n\t" 30 " .quad (%[key] - .) + %[bit0] \n\t" 31 " .popsection \n\t" 32 : : [key]"Si"(key), [bit0]"i"(branch) : : l_yes); 33 34 return false; 35 l_yes: 36 return true; 37 } 38 39 static __always_inline bool arch_static_branch_jump(struct static_key * const key, 40 const bool branch) 41 { 42 asm_volatile_goto( 43 "1: b %l[l_yes] \n\t" 44 " .pushsection __jump_table, \"aw\" \n\t" 45 " .align 3 \n\t" 46 " .long 1b - ., %l[l_yes] - . \n\t" 47 " .quad (%[key] - .) + %[bit0] \n\t" 48 " .popsection \n\t" 49 : : [key]"Si"(key), [bit0]"i"(branch) : : l_yes); 50 51 return false; 52 l_yes: 53 return true; 54 } 55 56 #endif /* __ASSEMBLY__ */ 57 #endif /* __ASM_JUMP_LABEL_H */ 58