[PATCH v3 16/21] crypto/arm64: sm3 - Switch to 'ksimd' scoped guard API

Ard Biesheuvel
2025-10-08T15:47:04Z

Switch to the more abstract 'scoped_ksimd()' API, which will be modified
in a future patch to transparently allocate a kernel mode FP/SIMD state
buffer on the stack, so that kernel mode FP/SIMD code remains
preemptible in principe, but without the memory overhead that adds 528
bytes to the size of struct task_struct.

Reviewed-by: Eric Biggers <ebiggers@kernel.org>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
arch/arm64/crypto/sm3-ce-glue.c | 15 ++++++++-------
arch/arm64/crypto/sm3-neon-glue.c | 16 ++++++----------
2 files changed, 14 insertions(+), 17 deletions(-)

diff --git a/arch/arm64/crypto/sm3-ce-glue.c b/arch/arm64/crypto/sm3-ce-glue.c
index eac6f5fa0abe..24c1fcfae072 100644
--- a/arch/arm64/crypto/sm3-ce-glue.c
+++ b/arch/arm64/crypto/sm3-ce-glue.c
@@ -5,7 +5,6 @@
* Copyright (C) 2018 Linaro Ltd <ard.biesheuvel@linaro.org>
*/

-#include <asm/neon.h>
#include <crypto/internal/hash.h>
#include <crypto/sm3.h>
#include <crypto/sm3_base.h>
@@ -13,6 +12,8 @@
#include <linux/kernel.h>
#include <linux/module.h>

+#include <asm/simd.h>
+
MODULE_DESCRIPTION("SM3 secure hash using ARMv8 Crypto Extensions");
MODULE_AUTHOR("Ard Biesheuvel <ard.biesheuvel@linaro.org>");
MODULE_LICENSE("GPL v2");
@@ -25,18 +26,18 @@ static int sm3_ce_update(struct shash_desc *desc, const u8 *data,
{
int remain;

- kernel_neon_begin();
- remain = sm3_base_do_update_blocks(desc, data, len, sm3_ce_transform);
- kernel_neon_end();
+ scoped_ksimd() {
+ remain = sm3_base_do_update_blocks(desc, data, len, sm3_ce_transform);
+ }
return remain;
}

static int sm3_ce_finup(struct shash_desc *desc, const u8 *data,
unsigned int len, u8 *out)
{
- kernel_neon_begin();
- sm3_base_do_finup(desc, data, len, sm3_ce_transform);
- kernel_neon_end();
+ scoped_ksimd() {
+ sm3_base_do_finup(desc, data, len, sm3_ce_transform);
+ }
return sm3_base_finish(desc, out);
}

diff --git a/arch/arm64/crypto/sm3-neon-glue.c b/arch/arm64/crypto/sm3-neon-glue.c
index 6c4611a503a3..15f30cc24f32 100644
--- a/arch/arm64/crypto/sm3-neon-glue.c
+++ b/arch/arm64/crypto/sm3-neon-glue.c
@@ -5,7 +5,7 @@
* Copyright (C) 2022 Tianjia Zhang <tianjia.zhang@linux.alibaba.com>
*/

-#include <asm/neon.h>
+#include <asm/simd.h>
#include <crypto/internal/hash.h>
#include <crypto/sm3.h>
#include <crypto/sm3_base.h>
@@ -20,20 +20,16 @@ asmlinkage void sm3_neon_transform(struct sm3_state *sst, u8 const *src,
static int sm3_neon_update(struct shash_desc *desc, const u8 *data,
unsigned int len)
{
- int remain;
-
- kernel_neon_begin();
- remain = sm3_base_do_update_blocks(desc, data, len, sm3_neon_transform);
- kernel_neon_end();
- return remain;
+ scoped_ksimd()
+ return sm3_base_do_update_blocks(desc, data, len,
+ sm3_neon_transform);
}

static int sm3_neon_finup(struct shash_desc *desc, const u8 *data,
unsigned int len, u8 *out)
{
- kernel_neon_begin();
- sm3_base_do_finup(desc, data, len, sm3_neon_transform);
- kernel_neon_end();
+ scoped_ksimd()
+ sm3_base_do_finup(desc, data, len, sm3_neon_transform);
return sm3_base_finish(desc, out);
}

--
2.51.0.710.ga91ca5db03-goog