xref: /openbmc/linux/arch/arm64/kernel/jump_label.c (revision 5c816641)
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/kernel/jump_label.c
7  */
8 #include <linux/kernel.h>
9 #include <linux/jump_label.h>
10 #include <asm/insn.h>
11 #include <asm/patching.h>
12 
13 void arch_jump_label_transform(struct jump_entry *entry,
14 			       enum jump_label_type type)
15 {
16 	void *addr = (void *)jump_entry_code(entry);
17 	u32 insn;
18 
19 	if (type == JUMP_LABEL_JMP) {
20 		insn = aarch64_insn_gen_branch_imm(jump_entry_code(entry),
21 						   jump_entry_target(entry),
22 						   AARCH64_INSN_BRANCH_NOLINK);
23 	} else {
24 		insn = aarch64_insn_gen_nop();
25 	}
26 
27 	aarch64_insn_patch_text_nosync(addr, insn);
28 }
29 
30 void arch_jump_label_transform_static(struct jump_entry *entry,
31 				      enum jump_label_type type)
32 {
33 	/*
34 	 * We use the architected A64 NOP in arch_static_branch, so there's no
35 	 * need to patch an identical A64 NOP over the top of it here. The core
36 	 * will call arch_jump_label_transform from a module notifier if the
37 	 * NOP needs to be replaced by a branch.
38 	 */
39 }
40