linux/arch/arm64/kernel/jump_label.c
Peter Zijlstra 76b235c6bc jump_label: Rename JUMP_LABEL_{EN,DIS}ABLE to JUMP_LABEL_{JMP,NOP}
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>
2015-08-03 11:34:12 +02:00

54 lines
1.6 KiB
C

/*
* Copyright (C) 2013 Huawei Ltd.
* Author: Jiang Liu <liuj97@gmail.com>
*
* Based on arch/arm/kernel/jump_label.c
*
* 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/>.
*/
#include <linux/kernel.h>
#include <linux/jump_label.h>
#include <asm/insn.h>
#ifdef HAVE_JUMP_LABEL
void arch_jump_label_transform(struct jump_entry *entry,
enum jump_label_type type)
{
void *addr = (void *)entry->code;
u32 insn;
if (type == JUMP_LABEL_JMP) {
insn = aarch64_insn_gen_branch_imm(entry->code,
entry->target,
AARCH64_INSN_BRANCH_NOLINK);
} else {
insn = aarch64_insn_gen_nop();
}
aarch64_insn_patch_text(&addr, &insn, 1);
}
void arch_jump_label_transform_static(struct jump_entry *entry,
enum jump_label_type type)
{
/*
* We use the architected A64 NOP in arch_static_branch, so there's no
* need to patch an identical A64 NOP over the top of it here. The core
* will call arch_jump_label_transform from a module notifier if the
* NOP needs to be replaced by a branch.
*/
}
#endif /* HAVE_JUMP_LABEL */