[PATCH 1/7] riscv: jump_label: Batch icache maintenance

Samuel Holland
2024-02-12T02:55:41Z

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: Samuel Holland <samuel.holland@sifive.com>
---

arch/riscv/include/asm/jump_label.h | 2 ++
arch/riscv/include/asm/patch.h | 1 +
arch/riscv/kernel/jump_label.c | 16 ++++++++++++----
arch/riscv/kernel/patch.c | 2 +-
4 files changed, 16 insertions(+), 5 deletions(-)

diff --git a/arch/riscv/include/asm/jump_label.h b/arch/riscv/include/asm/jump_label.h
index 4a35d787c019..6290b26f4a14 100644
--- a/arch/riscv/include/asm/jump_label.h
+++ b/arch/riscv/include/asm/jump_label.h
@@ -12,6 +12,8 @@
#include <linux/types.h>
#include <asm/asm.h>

+#define HAVE_JUMP_LABEL_BATCH
+
#define JUMP_LABEL_NOP_SIZE 4

static __always_inline bool arch_static_branch(struct static_key * const key,
diff --git a/arch/riscv/include/asm/patch.h b/arch/riscv/include/asm/patch.h
index e88b52d39eac..9f5d6e14c405 100644
--- a/arch/riscv/include/asm/patch.h
+++ b/arch/riscv/include/asm/patch.h
@@ -6,6 +6,7 @@
#ifndef _ASM_RISCV_PATCH_H
#define _ASM_RISCV_PATCH_H

+int patch_insn_write(void *addr, const void *insn, size_t len);
int patch_text_nosync(void *addr, const void *insns, size_t len);
int patch_text_set_nosync(void *addr, u8 c, size_t len);
int patch_text(void *addr, u32 *insns, int ninsns);
diff --git a/arch/riscv/kernel/jump_label.c b/arch/riscv/kernel/jump_label.c
index e6694759dbd0..11ad789c60c6 100644
--- a/arch/riscv/kernel/jump_label.c
+++ b/arch/riscv/kernel/jump_label.c
@@ -9,13 +9,14 @@
#include <linux/memory.h>
#include <linux/mutex.h>
#include <asm/bug.h>
+#include <asm/cacheflush.h>
#include <asm/patch.h>

#define RISCV_INSN_NOP 0x00000013U
#define RISCV_INSN_JAL 0x0000006fU

-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)
{
void *addr = (void *)jump_entry_code(entry);
u32 insn;
@@ -24,7 +25,7 @@ void arch_jump_label_transform(struct jump_entry *entry,
long offset = jump_entry_target(entry) - jump_entry_code(entry);

if (WARN_ON(offset & 1 || offset < -524288 || offset >= 524288))
- return;
+ return true;

insn = RISCV_INSN_JAL |
(((u32)offset & GENMASK(19, 12)) << (12 - 12)) |
@@ -36,6 +37,13 @@ void arch_jump_label_transform(struct jump_entry *entry,
}

mutex_lock(&text_mutex);
- patch_text_nosync(addr, &insn, sizeof(insn));
+ patch_insn_write(addr, &insn, sizeof(insn));
mutex_unlock(&text_mutex);
+
+ return true;
+}
+
+void arch_jump_label_transform_apply(void)
+{
+ flush_icache_all();
}
diff --git a/arch/riscv/kernel/patch.c b/arch/riscv/kernel/patch.c
index 37e87fdcf6a0..bccd9ed04a05 100644
--- a/arch/riscv/kernel/patch.c
+++ b/arch/riscv/kernel/patch.c
@@ -188,7 +188,7 @@ int patch_text_set_nosync(void *addr, u8 c, size_t len)
}
NOKPROBE_SYMBOL(patch_text_set_nosync);

-static int patch_insn_write(void *addr, const void *insn, size_t len)
+int patch_insn_write(void *addr, const void *insn, size_t len)
{
size_t patched = 0;
size_t size;
--
2.43.0