forked from Minki/linux
76b235c6bc
Since we've already stepped away from ENABLE is a JMP and DISABLE is a
NOP with the branch_default bits, and are going to make it even worse,
rename it to make it all clearer.
This way we don't mix multiple levels of logic attributes, but have a
plain 'physical' name for what the current instruction patching status
of a jump label is.
This is a first step in removing the naming confusion that has led to
a stream of avoidable bugs such as:
a833581e37 ("x86, perf: Fix static_key bug in load_mm_cr4()")
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
[ Beefed up the changelog. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
54 lines
1.6 KiB
C
54 lines
1.6 KiB
C
/*
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* Copyright (C) 2013 Huawei Ltd.
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* Author: Jiang Liu <liuj97@gmail.com>
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*
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* Based on arch/arm/kernel/jump_label.c
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <linux/kernel.h>
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#include <linux/jump_label.h>
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#include <asm/insn.h>
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#ifdef HAVE_JUMP_LABEL
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void arch_jump_label_transform(struct jump_entry *entry,
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enum jump_label_type type)
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{
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void *addr = (void *)entry->code;
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u32 insn;
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if (type == JUMP_LABEL_JMP) {
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insn = aarch64_insn_gen_branch_imm(entry->code,
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entry->target,
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AARCH64_INSN_BRANCH_NOLINK);
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} else {
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insn = aarch64_insn_gen_nop();
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}
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aarch64_insn_patch_text(&addr, &insn, 1);
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}
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void arch_jump_label_transform_static(struct jump_entry *entry,
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enum jump_label_type type)
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{
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/*
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* We use the architected A64 NOP in arch_static_branch, so there's no
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* need to patch an identical A64 NOP over the top of it here. The core
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* will call arch_jump_label_transform from a module notifier if the
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* NOP needs to be replaced by a branch.
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*/
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}
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#endif /* HAVE_JUMP_LABEL */
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