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Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
riscv: Add jump-label implementation
Add jump-label implementation based on the ARM64 version
and add CONFIG_JUMP_LABEL=y to the defconfigs.
Signed-off-by: Emil Renner Berthing <kernel@esmil.dk>
Reviewed-by: Björn Töpel <bjorn.topel@gmail.com>
Tested-by: Björn Töpel <bjorn.topel@gmail.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
authored by
Emil Renner Berthing
and committed by
Palmer Dabbelt
ebc00dde
11a54f42
+122
-1
+1
-1
Documentation/features/core/jump-labels/arch-support.txt
+1
-1
Documentation/features/core/jump-labels/arch-support.txt
+2
arch/riscv/Kconfig
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arch/riscv/Kconfig
···
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select GENERIC_TIME_VSYSCALL if MMU && 64BIT
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select HANDLE_DOMAIN_IRQ
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select HAVE_ARCH_AUDITSYSCALL
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select HAVE_ARCH_JUMP_LABEL
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select HAVE_ARCH_JUMP_LABEL_RELATIVE
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select HAVE_ARCH_KASAN if MMU && 64BIT
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select HAVE_ARCH_KGDB
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select HAVE_ARCH_KGDB_QXFER_PKT
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arch/riscv/configs/defconfig
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arch/riscv/configs/defconfig
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arch/riscv/configs/nommu_k210_defconfig
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arch/riscv/configs/nommu_k210_defconfig
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arch/riscv/configs/nommu_virt_defconfig
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arch/riscv/configs/nommu_virt_defconfig
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arch/riscv/configs/rv32_defconfig
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arch/riscv/configs/rv32_defconfig
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arch/riscv/include/asm/jump_label.h
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arch/riscv/include/asm/jump_label.h
···
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/* SPDX-License-Identifier: GPL-2.0-only */
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/*
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* Copyright (C) 2020 Emil Renner Berthing
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*
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* Based on arch/arm64/include/asm/jump_label.h
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*/
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#ifndef __ASM_JUMP_LABEL_H
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#define __ASM_JUMP_LABEL_H
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#ifndef __ASSEMBLY__
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#include <linux/types.h>
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#include <asm/asm.h>
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#define JUMP_LABEL_NOP_SIZE 4
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static __always_inline bool arch_static_branch(struct static_key *key,
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bool branch)
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{
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asm_volatile_goto(
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" .option push \n\t"
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" .option norelax \n\t"
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" .option norvc \n\t"
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"1: nop \n\t"
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" .option pop \n\t"
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" .pushsection __jump_table, \"aw\" \n\t"
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" .align " RISCV_LGPTR " \n\t"
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" .long 1b - ., %l[label] - . \n\t"
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" " RISCV_PTR " %0 - . \n\t"
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" .popsection \n\t"
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: : "i"(&((char *)key)[branch]) : : label);
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return false;
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label:
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return true;
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}
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static __always_inline bool arch_static_branch_jump(struct static_key *key,
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bool branch)
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{
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asm_volatile_goto(
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" .option push \n\t"
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" .option norelax \n\t"
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" .option norvc \n\t"
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"1: jal zero, %l[label] \n\t"
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" .option pop \n\t"
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" .pushsection __jump_table, \"aw\" \n\t"
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" .align " RISCV_LGPTR " \n\t"
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" .long 1b - ., %l[label] - . \n\t"
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" " RISCV_PTR " %0 - . \n\t"
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" .popsection \n\t"
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: : "i"(&((char *)key)[branch]) : : label);
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return false;
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label:
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return true;
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}
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#endif /* __ASSEMBLY__ */
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#endif /* __ASM_JUMP_LABEL_H */
+2
arch/riscv/kernel/Makefile
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arch/riscv/kernel/Makefile
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arch/riscv/kernel/jump_label.c
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arch/riscv/kernel/jump_label.c
···
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// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Copyright (C) 2020 Emil Renner Berthing
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*
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* Based on arch/arm64/kernel/jump_label.c
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*/
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#include <linux/jump_label.h>
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#include <linux/kernel.h>
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#include <linux/memory.h>
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#include <linux/mutex.h>
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#include <asm/bug.h>
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#include <asm/patch.h>
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#define RISCV_INSN_NOP 0x00000013U
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#define RISCV_INSN_JAL 0x0000006fU
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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 *)jump_entry_code(entry);
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u32 insn;
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if (type == JUMP_LABEL_JMP) {
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long offset = jump_entry_target(entry) - jump_entry_code(entry);
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if (WARN_ON(offset & 1 || offset < -524288 || offset >= 524288))
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return;
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insn = RISCV_INSN_JAL |
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(((u32)offset & GENMASK(19, 12)) << (12 - 12)) |
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(((u32)offset & GENMASK(11, 11)) << (20 - 11)) |
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(((u32)offset & GENMASK(10, 1)) << (21 - 1)) |
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(((u32)offset & GENMASK(20, 20)) << (31 - 20));
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} else {
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insn = RISCV_INSN_NOP;
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}
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mutex_lock(&text_mutex);
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patch_text_nosync(addr, &insn, sizeof(insn));
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mutex_unlock(&text_mutex);
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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 same instructions in the arch_static_branch and
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* arch_static_branch_jump inline functions, so there's no
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* need to patch them up here.
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* The core will call arch_jump_label_transform when those
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* instructions need to be replaced.
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*/
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}