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Message-ID: <CAAhV-H5QJQ2fcB5urye4Ffcbeynmjy7qN9qW=d0-Av2QhzpbxA@mail.gmail.com>
Date: Tue, 16 May 2023 10:01:18 +0800
From: Huacai Chen <chenhuacai@...nel.org>
To: Youling Tang <tangyouling@...ngson.cn>
Cc: Jonathan Corbet <corbet@....net>,
Peter Zijlstra <peterz@...radead.org>,
Josh Poimboeuf <jpoimboe@...nel.org>,
Jason Baron <jbaron@...mai.com>,
WANG Xuerui <kernel@...0n.name>,
Zhangjin Wu <falcon@...ylab.org>, linux-doc@...r.kernel.org,
linux-kernel@...r.kernel.org, loongarch@...ts.linux.dev
Subject: Re: [PATCH v3] LoongArch: Add jump-label implementation
Queued, thanks.
Huacai
On Mon, May 15, 2023 at 10:43 AM Youling Tang <tangyouling@...ngson.cn> wrote:
>
> Add support for jump labels based on the ARM64 version.
>
> Acked-by: Peter Zijlstra (Intel) <peterz@...radead.org>
> Signed-off-by: Youling Tang <tangyouling@...ngson.cn>
> ---
> Changes in v3:
> - Define the JUMP_TABLE_ENTRY macro so that arch_static_branch
> and arch_static_branch_jump can be shared.
> - Modify commit message.
>
> Changes in v2:
> - Fix build errors.
> - fix comment.
>
> .../core/jump-labels/arch-support.txt | 2 +-
> arch/loongarch/Kconfig | 2 +
> arch/loongarch/configs/loongson3_defconfig | 1 +
> arch/loongarch/include/asm/jump_label.h | 50 +++++++++++++++++++
> arch/loongarch/kernel/Makefile | 2 +
> arch/loongarch/kernel/jump_label.c | 23 +++++++++
> 6 files changed, 79 insertions(+), 1 deletion(-)
> create mode 100644 arch/loongarch/include/asm/jump_label.h
> create mode 100644 arch/loongarch/kernel/jump_label.c
>
> diff --git a/Documentation/features/core/jump-labels/arch-support.txt b/Documentation/features/core/jump-labels/arch-support.txt
> index 2328eada3a49..94d9dece580f 100644
> --- a/Documentation/features/core/jump-labels/arch-support.txt
> +++ b/Documentation/features/core/jump-labels/arch-support.txt
> @@ -13,7 +13,7 @@
> | csky: | ok |
> | hexagon: | TODO |
> | ia64: | TODO |
> - | loongarch: | TODO |
> + | loongarch: | ok |
> | m68k: | TODO |
> | microblaze: | TODO |
> | mips: | ok |
> diff --git a/arch/loongarch/Kconfig b/arch/loongarch/Kconfig
> index d38b066fc931..193a959a5611 100644
> --- a/arch/loongarch/Kconfig
> +++ b/arch/loongarch/Kconfig
> @@ -83,6 +83,8 @@ config LOONGARCH
> select GPIOLIB
> select HAS_IOPORT
> select HAVE_ARCH_AUDITSYSCALL
> + select HAVE_ARCH_JUMP_LABEL
> + select HAVE_ARCH_JUMP_LABEL_RELATIVE
> select HAVE_ARCH_MMAP_RND_BITS if MMU
> select HAVE_ARCH_SECCOMP_FILTER
> select HAVE_ARCH_TRACEHOOK
> diff --git a/arch/loongarch/configs/loongson3_defconfig b/arch/loongarch/configs/loongson3_defconfig
> index 6cd26dd3c134..33a0f5f742f6 100644
> --- a/arch/loongarch/configs/loongson3_defconfig
> +++ b/arch/loongarch/configs/loongson3_defconfig
> @@ -63,6 +63,7 @@ CONFIG_EFI_ZBOOT=y
> CONFIG_EFI_GENERIC_STUB_INITRD_CMDLINE_LOADER=y
> CONFIG_EFI_CAPSULE_LOADER=m
> CONFIG_EFI_TEST=m
> +CONFIG_JUMP_LABEL=y
> CONFIG_MODULES=y
> CONFIG_MODULE_FORCE_LOAD=y
> CONFIG_MODULE_UNLOAD=y
> diff --git a/arch/loongarch/include/asm/jump_label.h b/arch/loongarch/include/asm/jump_label.h
> new file mode 100644
> index 000000000000..4d8cbd5a8221
> --- /dev/null
> +++ b/arch/loongarch/include/asm/jump_label.h
> @@ -0,0 +1,50 @@
> +/* SPDX-License-Identifier: GPL-2.0-only */
> +/*
> + * Copyright (C) 2023 Loongson Technology Corporation Limited
> + *
> + * 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>
> +
> +#define JUMP_LABEL_NOP_SIZE 4
> +
> +#define JUMP_TABLE_ENTRY \
> + ".pushsection __jump_table, \"aw\" \n\t" \
> + ".align 3 \n\t" \
> + ".long 1b - ., %l[l_yes] - . \n\t" \
> + ".quad %0 - . \n\t" \
> + ".popsection \n\t"
> +
> +static __always_inline bool arch_static_branch(struct static_key * const key,
> + const bool branch)
> +{
> + asm_volatile_goto(
> + "1: nop \n\t"
> + JUMP_TABLE_ENTRY
> + : : "i"(&((char *)key)[branch]) : : l_yes);
> +
> + return false;
> +l_yes:
> + return true;
> +}
> +
> +static __always_inline bool arch_static_branch_jump(struct static_key * const key,
> + const bool branch)
> +{
> + asm_volatile_goto(
> + "1: b %l[l_yes] \n\t"
> + JUMP_TABLE_ENTRY
> + : : "i"(&((char *)key)[branch]) : : l_yes);
> +
> + return false;
> +l_yes:
> + return true;
> +}
> +
> +#endif /* __ASSEMBLY__ */
> +#endif /* __ASM_JUMP_LABEL_H */
> diff --git a/arch/loongarch/kernel/Makefile b/arch/loongarch/kernel/Makefile
> index 9a72d91cd104..64ea76f60e2c 100644
> --- a/arch/loongarch/kernel/Makefile
> +++ b/arch/loongarch/kernel/Makefile
> @@ -54,4 +54,6 @@ obj-$(CONFIG_HAVE_HW_BREAKPOINT) += hw_breakpoint.o
>
> obj-$(CONFIG_KPROBES) += kprobes.o kprobes_trampoline.o
>
> +obj-$(CONFIG_JUMP_LABEL) += jump_label.o
> +
> CPPFLAGS_vmlinux.lds := $(KBUILD_CFLAGS)
> diff --git a/arch/loongarch/kernel/jump_label.c b/arch/loongarch/kernel/jump_label.c
> new file mode 100644
> index 000000000000..b06245955f7a
> --- /dev/null
> +++ b/arch/loongarch/kernel/jump_label.c
> @@ -0,0 +1,23 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Copyright (C) 2023 Loongson Technology Corporation Limited
> + *
> + * Based on arch/arm64/kernel/jump_label.c
> + */
> +#include <linux/jump_label.h>
> +#include <linux/kernel.h>
> +#include <asm/inst.h>
> +
> +void arch_jump_label_transform(struct jump_entry *entry,
> + enum jump_label_type type)
> +{
> + void *addr = (void *)jump_entry_code(entry);
> + u32 insn;
> +
> + if (type == JUMP_LABEL_JMP)
> + insn = larch_insn_gen_b(jump_entry_code(entry), jump_entry_target(entry));
> + else
> + insn = larch_insn_gen_nop();
> +
> + larch_insn_patch_text(addr, insn);
> +}
> --
> 2.37.1
>
>
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