mirror of
https://github.com/torvalds/linux.git
synced 2024-12-12 14:12:51 +00:00
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
/*
|
|
* 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 */
|