[PATCH v3 18/21] arm64/xorblocks: Switch to 'ksimd' scoped guard API

Ard Biesheuvel
2025-10-08T15:47:06Z

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/include/asm/xor.h | 22 ++++++++------------
1 file changed, 9 insertions(+), 13 deletions(-)

diff --git a/arch/arm64/include/asm/xor.h b/arch/arm64/include/asm/xor.h
index befcd8a7abc9..c38e3d017a79 100644
--- a/arch/arm64/include/asm/xor.h
+++ b/arch/arm64/include/asm/xor.h
@@ -9,7 +9,7 @@
#include <linux/hardirq.h>
#include <asm-generic/xor.h>
#include <asm/hwcap.h>
-#include <asm/neon.h>
+#include <asm/simd.h>

#ifdef CONFIG_KERNEL_MODE_NEON

@@ -19,9 +19,8 @@ static void
xor_neon_2(unsigned long bytes, unsigned long * __restrict p1,
const unsigned long * __restrict p2)
{
- kernel_neon_begin();
- xor_block_inner_neon.do_2(bytes, p1, p2);
- kernel_neon_end();
+ scoped_ksimd()
+ xor_block_inner_neon.do_2(bytes, p1, p2);
}

static void
@@ -29,9 +28,8 @@ xor_neon_3(unsigned long bytes, unsigned long * __restrict p1,
const unsigned long * __restrict p2,
const unsigned long * __restrict p3)
{
- kernel_neon_begin();
- xor_block_inner_neon.do_3(bytes, p1, p2, p3);
- kernel_neon_end();
+ scoped_ksimd()
+ xor_block_inner_neon.do_3(bytes, p1, p2, p3);
}

static void
@@ -40,9 +38,8 @@ xor_neon_4(unsigned long bytes, unsigned long * __restrict p1,
const unsigned long * __restrict p3,
const unsigned long * __restrict p4)
{
- kernel_neon_begin();
- xor_block_inner_neon.do_4(bytes, p1, p2, p3, p4);
- kernel_neon_end();
+ scoped_ksimd()
+ xor_block_inner_neon.do_4(bytes, p1, p2, p3, p4);
}

static void
@@ -52,9 +49,8 @@ xor_neon_5(unsigned long bytes, unsigned long * __restrict p1,
const unsigned long * __restrict p4,
const unsigned long * __restrict p5)
{
- kernel_neon_begin();
- xor_block_inner_neon.do_5(bytes, p1, p2, p3, p4, p5);
- kernel_neon_end();
+ scoped_ksimd()
+ xor_block_inner_neon.do_5(bytes, p1, p2, p3, p4, p5);
}

static struct xor_block_template xor_block_arm64 = {
--
2.51.0.710.ga91ca5db03-goog