Re: [PATCH v2 2/2] LoongArch: Batch icache maintenance for jump_label

Huacai Chen
2026-04-11T13:13:26Z

Applied, thanks.

Huacai

On Sun, Apr 5, 2026 at 10:13 AM Youling Tang <youling.tang@linux.dev> wrote:
>
> From: Youling Tang <tangyouling@kylinos.cn>
>
> Switch to the batched version of the jump label update functions so
> instruction cache maintenance is deferred until the end of the update.
>
> Signed-off-by: Youling Tang <tangyouling@kylinos.cn>
> ---
> arch/loongarch/include/asm/jump_label.h | 1 +
> arch/loongarch/kernel/inst.c | 6 +++---
> arch/loongarch/kernel/jump_label.c | 13 +++++++++++--
> 3 files changed, 15 insertions(+), 5 deletions(-)
>
> diff --git a/arch/loongarch/include/asm/jump_label.h b/arch/loongarch/include/asm/jump_label.h
> index dcaecf69ea5a..ceb3dfa66188 100644
> --- a/arch/loongarch/include/asm/jump_label.h
> +++ b/arch/loongarch/include/asm/jump_label.h
> @@ -13,6 +13,7 @@
> #include <linux/stringify.h>
> #include <asm/asm.h>
>
> +#define HAVE_JUMP_LABEL_BATCH
> #define JUMP_LABEL_NOP_SIZE 4
>
> #ifdef CONFIG_32BIT
> diff --git a/arch/loongarch/kernel/inst.c b/arch/loongarch/kernel/inst.c
> index 1a728082944c..0b9228b7c13a 100644
> --- a/arch/loongarch/kernel/inst.c
> +++ b/arch/loongarch/kernel/inst.c
> @@ -209,6 +209,9 @@ int larch_insn_write(void *addr, u32 insn)
> int ret;
> unsigned long flags = 0;
>
> + if ((unsigned long)addr & 3)
> + return -EINVAL;
> +
> raw_spin_lock_irqsave(&patch_lock, flags);
> ret = copy_to_kernel_nofault(addr, &insn, LOONGARCH_INSN_SIZE);
> raw_spin_unlock_irqrestore(&patch_lock, flags);
> @@ -221,9 +224,6 @@ int larch_insn_patch_text(void *addr, u32 insn)
> int ret;
> u32 *tp = addr;
>
> - if ((unsigned long)tp & 3)
> - return -EINVAL;
> -
> ret = larch_insn_write(tp, insn);
> if (!ret)
> flush_icache_range((unsigned long)tp,
> diff --git a/arch/loongarch/kernel/jump_label.c b/arch/loongarch/kernel/jump_label.c
> index 31891214b767..f5a394bdb5f3 100644
> --- a/arch/loongarch/kernel/jump_label.c
> +++ b/arch/loongarch/kernel/jump_label.c
> @@ -6,9 +6,11 @@
> */
> #include <linux/kernel.h>
> #include <linux/jump_label.h>
> +#include <asm/cacheflush.h>
> #include <asm/inst.h>
>
> -void arch_jump_label_transform(struct jump_entry *entry, enum jump_label_type type)
> +bool arch_jump_label_transform_queue(struct jump_entry *entry,
> + enum jump_label_type type)
> {
> u32 insn;
> void *addr = (void *)jump_entry_code(entry);
> @@ -18,5 +20,12 @@ void arch_jump_label_transform(struct jump_entry *entry, enum jump_label_type ty
> else
> insn = larch_insn_gen_nop();
>
> - larch_insn_patch_text(addr, insn);
> + larch_insn_write(addr, insn);
> +
> + return true;
> +}
> +
> +void arch_jump_label_transform_apply(void)
> +{
> + flush_icache_all();
> }
> --
> 2.43.0
>