[PATCH v3 05/21] ARM/simd: Add scoped guard API for kernel mode SIMD

Ard Biesheuvel
2025-10-08T15:46:51Z

Implement the ksimd scoped guard API so that it can be used by code that
supports both ARM and arm64.

Reviewed-by: Kees Cook <kees@kernel.org>
Reviewed-by: Eric Biggers <ebiggers@kernel.org>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
arch/arm/include/asm/simd.h | 7 +++++++
1 file changed, 7 insertions(+)

diff --git a/arch/arm/include/asm/simd.h b/arch/arm/include/asm/simd.h
index be08a8da046f..8549fa8b7253 100644
--- a/arch/arm/include/asm/simd.h
+++ b/arch/arm/include/asm/simd.h
@@ -2,14 +2,21 @@
#ifndef _ASM_SIMD_H
#define _ASM_SIMD_H

+#include <linux/cleanup.h>
#include <linux/compiler_attributes.h>
#include <linux/preempt.h>
#include <linux/types.h>

+#include <asm/neon.h>
+
static __must_check inline bool may_use_simd(void)
{
return IS_ENABLED(CONFIG_KERNEL_MODE_NEON) && !in_hardirq()
&& !irqs_disabled();
}

+DEFINE_LOCK_GUARD_0(ksimd, kernel_neon_begin(), kernel_neon_end())
+
+#define scoped_ksimd() scoped_guard(ksimd)
+
#endif /* _ASM_SIMD_H */
--
2.51.0.710.ga91ca5db03-goog