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| author | Emil Renner Berthing <kernel@esmil.dk> | 2020-07-14 09:40:44 +0200 |
|---|---|---|
| committer | Palmer Dabbelt <palmerdabbelt@google.com> | 2020-07-30 11:37:43 -0700 |
| commit | ebc00dde8a975a543f5e1a7cdac93fef89fefe58 (patch) | |
| tree | e965bd70c1475527a1282e166f47c45b43ce8129 /arch/riscv/include | |
| parent | 11a54f422b0d2680be57bbb9f85696ef89d9cda1 (diff) | |
| download | lwn-ebc00dde8a975a543f5e1a7cdac93fef89fefe58.tar.gz lwn-ebc00dde8a975a543f5e1a7cdac93fef89fefe58.zip | |
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>
Diffstat (limited to 'arch/riscv/include')
| -rw-r--r-- | arch/riscv/include/asm/jump_label.h | 60 |
1 files changed, 60 insertions, 0 deletions
diff --git a/arch/riscv/include/asm/jump_label.h b/arch/riscv/include/asm/jump_label.h new file mode 100644 index 000000000000..38af2ec7b9bf --- /dev/null +++ b/arch/riscv/include/asm/jump_label.h @@ -0,0 +1,60 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Copyright (C) 2020 Emil Renner Berthing + * + * Based on arch/arm64/include/asm/jump_label.h + */ +#ifndef __ASM_JUMP_LABEL_H +#define __ASM_JUMP_LABEL_H + +#ifndef __ASSEMBLY__ + +#include <linux/types.h> +#include <asm/asm.h> + +#define JUMP_LABEL_NOP_SIZE 4 + +static __always_inline bool arch_static_branch(struct static_key *key, + bool branch) +{ + asm_volatile_goto( + " .option push \n\t" + " .option norelax \n\t" + " .option norvc \n\t" + "1: nop \n\t" + " .option pop \n\t" + " .pushsection __jump_table, \"aw\" \n\t" + " .align " RISCV_LGPTR " \n\t" + " .long 1b - ., %l[label] - . \n\t" + " " RISCV_PTR " %0 - . \n\t" + " .popsection \n\t" + : : "i"(&((char *)key)[branch]) : : label); + + return false; +label: + return true; +} + +static __always_inline bool arch_static_branch_jump(struct static_key *key, + bool branch) +{ + asm_volatile_goto( + " .option push \n\t" + " .option norelax \n\t" + " .option norvc \n\t" + "1: jal zero, %l[label] \n\t" + " .option pop \n\t" + " .pushsection __jump_table, \"aw\" \n\t" + " .align " RISCV_LGPTR " \n\t" + " .long 1b - ., %l[label] - . \n\t" + " " RISCV_PTR " %0 - . \n\t" + " .popsection \n\t" + : : "i"(&((char *)key)[branch]) : : label); + + return false; +label: + return true; +} + +#endif /* __ASSEMBLY__ */ +#endif /* __ASM_JUMP_LABEL_H */ |