| /* |
| * alternative runtime patching |
| * inspired by the x86 version |
| * |
| * Copyright (C) 2014 ARM Ltd. |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License version 2 as |
| * published by the Free Software Foundation. |
| * |
| * This program is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| * GNU General Public License for more details. |
| * |
| * You should have received a copy of the GNU General Public License |
| * along with this program. If not, see <http://www.gnu.org/licenses/>. |
| */ |
| |
| #define pr_fmt(fmt) "alternatives: " fmt |
| |
| #include <linux/init.h> |
| #include <linux/cpu.h> |
| #include <asm/cacheflush.h> |
| #include <asm/alternative.h> |
| #include <asm/cpufeature.h> |
| #include <asm/insn.h> |
| #include <linux/stop_machine.h> |
| |
| extern struct alt_instr __alt_instructions[], __alt_instructions_end[]; |
| |
| static int __apply_alternatives(void *dummy) |
| { |
| struct alt_instr *alt; |
| u32 *origptr, *replptr, *endptr; |
| |
| for (alt = __alt_instructions; alt < __alt_instructions_end; alt++) { |
| if (!cpus_have_cap(alt->cpufeature)) |
| continue; |
| |
| BUG_ON(alt->alt_len != alt->orig_len); |
| |
| pr_info_once("patching kernel code\n"); |
| |
| origptr = (void *)&alt->orig_offset + alt->orig_offset; |
| endptr = (void *)origptr + alt->orig_len; |
| replptr = (void *)&alt->alt_offset + alt->alt_offset; |
| for (; origptr < endptr; origptr++, replptr++) |
| BUG_ON(aarch64_insn_patch_text_nosync(origptr, *replptr)); |
| } |
| |
| return 0; |
| } |
| |
| void apply_alternatives(void) |
| { |
| /* better not try code patching on a live SMP system */ |
| stop_machine(__apply_alternatives, NULL, NULL); |
| } |
| |
| void free_alternatives_memory(void) |
| { |
| free_reserved_area(__alt_instructions, __alt_instructions_end, |
| 0, "alternatives"); |
| } |