On Wed, Aug 06, 2025 at 02:05:04AM +0000, ChenMiao wrote:
> From: chenmiao <[email protected]>
>
> Implemented the full functionality of jump_label, of course,
> with text patching supported by just one API.
>
> By the way, add new macro OPENRISC_INSN_NOP in insn-def.h to use.
>
> - V2: using the patch_insn_write(void *addr, u32 insn) not the
> const void *insn.
>
> Link: https://lore.kernel.org/openrisc/aJIC8o1WmVHol9RY@antec/T/#t
>
> Signed-off-by: chenmiao <[email protected]>
> ---
> .../core/jump-labels/arch-support.txt | 2 +-
> arch/openrisc/Kconfig | 2 +
> arch/openrisc/configs/or1ksim_defconfig | 19 ++----
> arch/openrisc/configs/virt_defconfig | 1 +
> arch/openrisc/include/asm/insn-def.h | 3 +
> arch/openrisc/include/asm/jump_label.h | 68 +++++++++++++++++++
> arch/openrisc/kernel/Makefile | 1 +
> arch/openrisc/kernel/jump_label.c | 53 +++++++++++++++
> arch/openrisc/kernel/setup.c | 2 +
> 9 files changed, 138 insertions(+), 13 deletions(-)
> create mode 100644 arch/openrisc/include/asm/jump_label.h
> create mode 100644 arch/openrisc/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 ccada815569f..683de7c15058 100644
> --- a/Documentation/features/core/jump-labels/arch-support.txt
> +++ b/Documentation/features/core/jump-labels/arch-support.txt
> @@ -17,7 +17,7 @@
> | microblaze: | TODO |
> | mips: | ok |
> | nios2: | TODO |
> - | openrisc: | TODO |
> + | openrisc: | ok |
> | parisc: | ok |
> | powerpc: | ok |
> | riscv: | ok |
> diff --git a/arch/openrisc/Kconfig b/arch/openrisc/Kconfig
> index b38fee299bc4..9156635dd264 100644
> --- a/arch/openrisc/Kconfig
> +++ b/arch/openrisc/Kconfig
> @@ -24,6 +24,8 @@ config OPENRISC
> select GENERIC_PCI_IOMAP
> select GENERIC_IOREMAP
> select GENERIC_CPU_DEVICES
> + select HAVE_ARCH_JUMP_LABEL
> + select HAVE_ARCH_JUMP_LABEL_RELATIVE
> select HAVE_PCI
> select HAVE_UID16
> select HAVE_PAGE_SIZE_8KB
> diff --git a/arch/openrisc/configs/or1ksim_defconfig
> b/arch/openrisc/configs/or1ksim_defconfig
> index 59fe33cefba2..769705ac24d5 100644
> --- a/arch/openrisc/configs/or1ksim_defconfig
> +++ b/arch/openrisc/configs/or1ksim_defconfig
> @@ -3,26 +3,23 @@ CONFIG_LOG_BUF_SHIFT=14
> CONFIG_BLK_DEV_INITRD=y
> # CONFIG_RD_GZIP is not set
> CONFIG_EXPERT=y
> -# CONFIG_KALLSYMS is not set
> # CONFIG_EPOLL is not set
> # CONFIG_TIMERFD is not set
> # CONFIG_EVENTFD is not set
> # CONFIG_AIO is not set
> -# CONFIG_VM_EVENT_COUNTERS is not set
> -# CONFIG_COMPAT_BRK is not set
> -CONFIG_SLUB=y
> -CONFIG_SLUB_TINY=y
> -CONFIG_MODULES=y
> -# CONFIG_BLOCK is not set
> +# CONFIG_KALLSYMS is not set
> CONFIG_BUILTIN_DTB_NAME="or1ksim"
> CONFIG_HZ_100=y
> +CONFIG_JUMP_LABEL=y
> +CONFIG_MODULES=y
> +# CONFIG_BLOCK is not set
> +CONFIG_SLUB_TINY=y
> +# CONFIG_COMPAT_BRK is not set
> +# CONFIG_VM_EVENT_COUNTERS is not set
> CONFIG_NET=y
> CONFIG_PACKET=y
> CONFIG_UNIX=y
> CONFIG_INET=y
> -# CONFIG_INET_XFRM_MODE_TRANSPORT is not set
> -# CONFIG_INET_XFRM_MODE_TUNNEL is not set
> -# CONFIG_INET_XFRM_MODE_BEET is not set
> # CONFIG_INET_DIAG is not set
> CONFIG_TCP_CONG_ADVANCED=y
> # CONFIG_TCP_CONG_BIC is not set
> @@ -35,7 +32,6 @@ CONFIG_DEVTMPFS=y
> CONFIG_DEVTMPFS_MOUNT=y
> # CONFIG_PREVENT_FIRMWARE_BUILD is not set
> # CONFIG_FW_LOADER is not set
> -CONFIG_PROC_DEVICETREE=y
> CONFIG_NETDEVICES=y
> CONFIG_ETHOC=y
> CONFIG_MICREL_PHY=y
> @@ -53,4 +49,3 @@ CONFIG_SERIAL_OF_PLATFORM=y
> # CONFIG_DNOTIFY is not set
> CONFIG_TMPFS=y
> CONFIG_NFS_FS=y
> -# CONFIG_ENABLE_MUST_CHECK is not set
> diff --git a/arch/openrisc/configs/virt_defconfig
> b/arch/openrisc/configs/virt_defconfig
> index c1b69166c500..4a80c5794877 100644
> --- a/arch/openrisc/configs/virt_defconfig
> +++ b/arch/openrisc/configs/virt_defconfig
> @@ -12,6 +12,7 @@ CONFIG_NR_CPUS=8
> CONFIG_SMP=y
> CONFIG_HZ_100=y
> # CONFIG_OPENRISC_NO_SPR_SR_DSX is not set
> +CONFIG_JUMP_LABEL=y
> # CONFIG_COMPAT_BRK is not set
> CONFIG_NET=y
> CONFIG_PACKET=y
The defconfig updates look quite different. Did you use savedefconfig for both
of them?
> diff --git a/arch/openrisc/include/asm/insn-def.h
> b/arch/openrisc/include/asm/insn-def.h
> index dc8d16db1579..2ccdbb37c27c 100644
> --- a/arch/openrisc/include/asm/insn-def.h
> +++ b/arch/openrisc/include/asm/insn-def.h
> @@ -9,4 +9,7 @@
> /* or1k instructions are always 32 bits. */
> #define OPENRISC_INSN_SIZE 4
>
> +/* or1k nop instruction code */
> +#define OPENRISC_INSN_NOP 0x15000000U
I see you use this header again here, note that in
arch/openrisc/kernel/signal.c. We write instructions to memory too for the
sigreturn trampoline.
Also, you use OPENRISC_INSN_SIZE below. Could you move this header to this
patch completely? I don't think its needed in the patching patch.
> #endif /* __ASM_INSN_DEF_H */
> diff --git a/arch/openrisc/include/asm/jump_label.h
> b/arch/openrisc/include/asm/jump_label.h
> new file mode 100644
> index 000000000000..03afca9c3a1f
> --- /dev/null
> +++ b/arch/openrisc/include/asm/jump_label.h
> @@ -0,0 +1,68 @@
> +/* SPDX-License-Identifier: GPL-2.0-only */
> +/*
> + * Copyright (C) 2025 Chen Miao
> + *
> + * Based on arch/arm/include/asm/jump_label.h
> + */
> +#ifndef __ASM_JUMP_LABEL_H
> +#define __ASM_JUMP_LABEL_H
Can this be __ASM_OPENRISC_JUMP_LABEL_H?
> +#ifndef __ASSEMBLY__
Note upstream this is now __ASSEMBLER__.
> +#include <linux/types.h>
> +#include <asm/insn-def.h>
> +
> +#define HAVE_JUMP_LABEL_BATCH
> +
> +#define JUMP_LABEL_NOP_SIZE OPENRISC_INSN_SIZE
> +
> +/*
> + * should aligned 4
> + * for jump_label relative
> + * entry.code = nop.addr - . -> return false
> + * entry.target = l_yes - . -> return true
> + * entry.key = key - .
> + */
> +#define JUMP_TABLE_ENTRY(key, label) \
> + ".pushsection __jump_table, \"aw\" \n\t" \
> + ".align 4 \n\t" \
> + ".long 1b - ., " label " - . \n\t" \
> + ".long " key " - . \n\t" \
> + ".popsection \n\t"
> +
> +#define ARCH_STATIC_BRANCH_ASM(key, label) \
> + ".align 4 \n\t" \
> + "1: l.nop \n\t" \
> + " l.nop \n\t" \
> + JUMP_TABLE_ENTRY(key, label)
> +
> +static __always_inline bool arch_static_branch(struct static_key *const key,
> + const bool branch)
> +{
> + asm goto (ARCH_STATIC_BRANCH_ASM("%0", "%l[l_yes]")
> + ::"i"(&((char *)key)[branch])::l_yes);
> +
> + return false;
> +l_yes:
> + return true;
> +}
> +
> +#define ARCH_STATIC_BRANCH_JUMP_ASM(key, label) \
> + ".align 4 \n\t" \
> + "1: l.j " label " \n\t" \
> + " l.nop \n\t" \
> + JUMP_TABLE_ENTRY(key, label)
> +
> +static __always_inline bool
> +arch_static_branch_jump(struct static_key *const key, const bool branch)
> +{
> + asm goto (ARCH_STATIC_BRANCH_JUMP_ASM("%0", "%l[l_yes]")
> + ::"i"(&((char *)key)[branch])::l_yes);
> +
> + return false;
> +l_yes:
> + return true;
> +}
> +
> +#endif /* __ASSEMBLY__ */
> +#endif /* __ASM_JUMP_LABEL_H */
> diff --git a/arch/openrisc/kernel/Makefile b/arch/openrisc/kernel/Makefile
> index f0957ce16d6b..19e0eb94f2eb 100644
> --- a/arch/openrisc/kernel/Makefile
> +++ b/arch/openrisc/kernel/Makefile
> @@ -9,6 +9,7 @@ obj-y := head.o setup.o or32_ksyms.o process.o dma.o \
> traps.o time.o irq.o entry.o ptrace.o signal.o \
> sys_call_table.o unwinder.o cacheinfo.o
>
> +obj-$(CONFIG_JUMP_LABEL) += jump_label.o
> obj-$(CONFIG_SMP) += smp.o sync-timer.o
> obj-$(CONFIG_STACKTRACE) += stacktrace.o
> obj-$(CONFIG_MODULES) += module.o
> diff --git a/arch/openrisc/kernel/jump_label.c
> b/arch/openrisc/kernel/jump_label.c
> new file mode 100644
> index 000000000000..ce259ba30258
> --- /dev/null
> +++ b/arch/openrisc/kernel/jump_label.c
> @@ -0,0 +1,53 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Copyright (C) 2025 Chen Miao
> + *
> + * Based on arch/arm/kernel/jump_label.c
> + */
> +#include <linux/jump_label.h>
> +#include <linux/kernel.h>
> +#include <linux/memory.h>
> +#include <asm/bug.h>
> +#include <asm/cacheflush.h>
> +#include <asm/text-patching.h>
> +
> +bool arch_jump_label_transform_queue(struct jump_entry *entry,
> + enum jump_label_type type)
> +{
> + void *addr = (void *)jump_entry_code(entry);
> + u32 insn;
> +
> + if (type == JUMP_LABEL_JMP) {
> + long offset;
> +
> + offset = jump_entry_target(entry) - jump_entry_code(entry);
> + /*
> + * The actual maximum range of the l.j instruction's offset is
> -134,217,728
> + * ~ 134,217,724 (sign 26-bit imm).
> + * For the original jump range, we need to right-shift N by 2
> to obtain the
> + * instruction's offset.
> + */
> + if (unlikely(offset < -134217728 || offset > 134217724)) {
> + WARN_ON_ONCE(true);
> + }
> + /* 26bit imm mask */
> + offset = (offset >> 2) & 0x03ffffff;
> +
> + insn = offset;
> + } else {
> + insn = OPENRISC_INSN_NOP;
> + }
> +
> + if (early_boot_irqs_disabled) {
> + copy_to_kernel_nofault(addr, &insn, sizeof(insn));
> + } else {
> + patch_insn_write(addr, insn);
> + }
> + return true;
> +}
> +
> +void arch_jump_label_transform_apply(void)
> +{
> + // flush
Could you use the /* */ comment style? Is this really flushing?
> + kick_all_cpus_sync();
> +}
> diff --git a/arch/openrisc/kernel/setup.c b/arch/openrisc/kernel/setup.c
> index a9fb9cc6779e..000a9cc10e6f 100644
> --- a/arch/openrisc/kernel/setup.c
> +++ b/arch/openrisc/kernel/setup.c
> @@ -249,6 +249,8 @@ void __init setup_arch(char **cmdline_p)
> initrd_below_start_ok = 1;
> }
> #endif
> + /* perform jump_table sorting before paging_init locks down read only
> memory */
> + jump_label_init();
>
> /* paging_init() sets up the MMU and marks all pages as reserved */
> paging_init();
> --
> 2.45.2
>
