0276ebf166
commit e9666d10a5677a494260d60d1fa0b73cc7646eb3 upstream.
Currently, CONFIG_JUMP_LABEL just means "I _want_ to use jump label".
The jump label is controlled by HAVE_JUMP_LABEL, which is defined
like this:
#if defined(CC_HAVE_ASM_GOTO) && defined(CONFIG_JUMP_LABEL)
# define HAVE_JUMP_LABEL
#endif
We can improve this by testing 'asm goto' support in Kconfig, then
make JUMP_LABEL depend on CC_HAS_ASM_GOTO.
Ugly #ifdef HAVE_JUMP_LABEL will go away, and CONFIG_JUMP_LABEL will
match to the real kernel capability.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
[nc: Fix trivial conflicts in 4.19
arch/xtensa/kernel/jump_label.c doesn't exist yet
Ensured CC_HAVE_ASM_GOTO and HAVE_JUMP_LABEL were sufficiently
eliminated]
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
49 lines
1.5 KiB
C
49 lines
1.5 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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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_nosync(addr, insn);
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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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