[PATCH v4 resend 3/7] arm64/fpsimd: Don't warn when EFI execution context is preemptible

Ard Biesheuvel
2025-10-15T21:01:06Z

Kernel mode FP/SIMD no longer requires preemption to be disabled, so
only warn on uses of FP/SIMD from preemptible context if the fallback
path is taken for cases where kernel mode NEON would not be allowed
otherwise.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
arch/arm64/kernel/fpsimd.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c
index e3f8f51748bc..3d848c89604e 100644
--- a/arch/arm64/kernel/fpsimd.c
+++ b/arch/arm64/kernel/fpsimd.c
@@ -1934,11 +1934,11 @@ void __efi_fpsimd_begin(void)
if (!system_supports_fpsimd())
return;

- WARN_ON(preemptible());
-
if (may_use_simd()) {
kernel_neon_begin();
} else {
+ WARN_ON(preemptible());
+
/*
* If !efi_sve_state, SVE can't be in use yet and doesn't need
* preserving:
--
2.51.0.869.ge66316f041-goog