2 * Copyright (C) 2013 Huawei Ltd.
3 * Author: Jiang Liu <liuj97@gmail.com>
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License version 2 as
7 * published by the Free Software Foundation.
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
14 * You should have received a copy of the GNU General Public License
15 * along with this program. If not, see <http://www.gnu.org/licenses/>.
17 #include <linux/compiler.h>
18 #include <linux/kernel.h>
21 static int aarch64_insn_encoding_class[] = {
22 AARCH64_INSN_CLS_UNKNOWN,
23 AARCH64_INSN_CLS_UNKNOWN,
24 AARCH64_INSN_CLS_UNKNOWN,
25 AARCH64_INSN_CLS_UNKNOWN,
26 AARCH64_INSN_CLS_LDST,
27 AARCH64_INSN_CLS_DP_REG,
28 AARCH64_INSN_CLS_LDST,
29 AARCH64_INSN_CLS_DP_FPSIMD,
30 AARCH64_INSN_CLS_DP_IMM,
31 AARCH64_INSN_CLS_DP_IMM,
32 AARCH64_INSN_CLS_BR_SYS,
33 AARCH64_INSN_CLS_BR_SYS,
34 AARCH64_INSN_CLS_LDST,
35 AARCH64_INSN_CLS_DP_REG,
36 AARCH64_INSN_CLS_LDST,
37 AARCH64_INSN_CLS_DP_FPSIMD,
40 enum aarch64_insn_encoding_class __kprobes aarch64_get_insn_class(u32 insn)
42 return aarch64_insn_encoding_class[(insn >> 25) & 0xf];
45 /* NOP is an alias of HINT */
46 bool __kprobes aarch64_insn_is_nop(u32 insn)
48 if (!aarch64_insn_is_hint(insn))
51 switch (insn & 0xFE0) {
52 case AARCH64_INSN_HINT_YIELD:
53 case AARCH64_INSN_HINT_WFE:
54 case AARCH64_INSN_HINT_WFI:
55 case AARCH64_INSN_HINT_SEV:
56 case AARCH64_INSN_HINT_SEVL:
63 static bool __kprobes __aarch64_insn_hotpatch_safe(u32 insn)
65 if (aarch64_get_insn_class(insn) != AARCH64_INSN_CLS_BR_SYS)
68 return aarch64_insn_is_b(insn) ||
69 aarch64_insn_is_bl(insn) ||
70 aarch64_insn_is_svc(insn) ||
71 aarch64_insn_is_hvc(insn) ||
72 aarch64_insn_is_smc(insn) ||
73 aarch64_insn_is_brk(insn) ||
74 aarch64_insn_is_nop(insn);
78 * ARM Architecture Reference Manual for ARMv8 Profile-A, Issue A.a
79 * Section B2.6.5 "Concurrent modification and execution of instructions":
80 * Concurrent modification and execution of instructions can lead to the
81 * resulting instruction performing any behavior that can be achieved by
82 * executing any sequence of instructions that can be executed from the
83 * same Exception level, except where the instruction before modification
84 * and the instruction after modification is a B, BL, NOP, BKPT, SVC, HVC,
87 bool __kprobes aarch64_insn_hotpatch_safe(u32 old_insn, u32 new_insn)
89 return __aarch64_insn_hotpatch_safe(old_insn) &&
90 __aarch64_insn_hotpatch_safe(new_insn);