arch/arm64/kernel/jump_label.c

   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 #ifdef HAVE_JUMP_LABEL
  24
  25 void arch_jump_label_transform(struct jump_entry *entry,
  26                                enum jump_label_type type)
  27 {
  28         void *addr = (void *)entry->code;
  29         u32 insn;
  30
  31         if (type == JUMP_LABEL_JMP) {
  32                 insn = aarch64_insn_gen_branch_imm(entry->code,
  33                                                    entry->target,
  34                                                    AARCH64_INSN_BRANCH_NOLINK);
  35         } else {
  36                 insn = aarch64_insn_gen_nop();
  37         }
  38
  39         aarch64_insn_patch_text(&addr, &insn, 1);
  40 }
  41
  42 void arch_jump_label_transform_static(struct jump_entry *entry,
  43                                       enum jump_label_type type)
  44 {
  45         /*
  46          * We use the architected A64 NOP in arch_static_branch, so there's no
  47          * need to patch an identical A64 NOP over the top of it here. The core
  48          * will call arch_jump_label_transform from a module notifier if the
  49          * NOP needs to be replaced by a branch.
  50          */
  51 }
  52
  53 #endif  /* HAVE_JUMP_LABEL */