1 /* 2 * Copyright (C) 2013 Huawei Ltd. 3 * Author: Jiang Liu <liuj97@gmail.com> 4 * 5 * Based on arch/arm/kernel/jump_label.c 6 * 7 * This program is free software; you can redistribute it and/or modify 8 * it under the terms of the GNU General Public License version 2 as 9 * published by the Free Software Foundation. 10 * 11 * This program is distributed in the hope that it will be useful, 12 * but WITHOUT ANY WARRANTY; without even the implied warranty of 13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 * GNU General Public License for more details. 15 * 16 * You should have received a copy of the GNU General Public License 17 * along with this program. If not, see <http://www.gnu.org/licenses/>. 18 */ 19 #include <linux/kernel.h> 20 #include <linux/jump_label.h> 21 #include <asm/insn.h> 22 23 void arch_jump_label_transform(struct jump_entry *entry, 24 enum jump_label_type type) 25 { 26 void *addr = (void *)jump_entry_code(entry); 27 u32 insn; 28 29 if (type == JUMP_LABEL_JMP) { 30 insn = aarch64_insn_gen_branch_imm(jump_entry_code(entry), 31 jump_entry_target(entry), 32 AARCH64_INSN_BRANCH_NOLINK); 33 } else { 34 insn = aarch64_insn_gen_nop(); 35 } 36 37 aarch64_insn_patch_text_nosync(addr, insn); 38 } 39 40 void arch_jump_label_transform_static(struct jump_entry *entry, 41 enum jump_label_type type) 42 { 43 /* 44 * We use the architected A64 NOP in arch_static_branch, so there's no 45 * need to patch an identical A64 NOP over the top of it here. The core 46 * will call arch_jump_label_transform from a module notifier if the 47 * NOP needs to be replaced by a branch. 48 */ 49 } 50