From 9732cafd9dc0206479be919baf0067239f0a63ca Mon Sep 17 00:00:00 2001 From: Jiang Liu Date: Tue, 7 Jan 2014 22:17:13 +0800 Subject: arm64, jump label: optimize jump label implementation Optimize jump label implementation for ARM64 by dynamically patching kernel text. Reviewed-by: Will Deacon Signed-off-by: Jiang Liu Signed-off-by: Catalin Marinas --- arch/arm64/include/asm/jump_label.h | 52 +++++++++++++++++++++++++++++++++++++ 1 file changed, 52 insertions(+) create mode 100644 arch/arm64/include/asm/jump_label.h (limited to 'arch/arm64/include') diff --git a/arch/arm64/include/asm/jump_label.h b/arch/arm64/include/asm/jump_label.h new file mode 100644 index 000000000000..076a1c714049 --- /dev/null +++ b/arch/arm64/include/asm/jump_label.h @@ -0,0 +1,52 @@ +/* + * Copyright (C) 2013 Huawei Ltd. + * Author: Jiang Liu + * + * Based on arch/arm/include/asm/jump_label.h + * + * 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 . + */ +#ifndef __ASM_JUMP_LABEL_H +#define __ASM_JUMP_LABEL_H +#include +#include + +#ifdef __KERNEL__ + +#define JUMP_LABEL_NOP_SIZE AARCH64_INSN_SIZE + +static __always_inline bool arch_static_branch(struct static_key *key) +{ + asm goto("1: nop\n\t" + ".pushsection __jump_table, \"aw\"\n\t" + ".align 3\n\t" + ".quad 1b, %l[l_yes], %c0\n\t" + ".popsection\n\t" + : : "i"(key) : : l_yes); + + return false; +l_yes: + return true; +} + +#endif /* __KERNEL__ */ + +typedef u64 jump_label_t; + +struct jump_entry { + jump_label_t code; + jump_label_t target; + jump_label_t key; +}; + +#endif /* __ASM_JUMP_LABEL_H */ -- cgit v1.2.1