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

Youling Tang
2026-04-05T02:13:37Z

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