[PATCH v3 3/7] arm64: cpufeature: Fix the type of no FP/SIMD capability

Suzuki K Poulose suzuki.poulose at arm.com
Mon Jan 13 15:30:19 PST 2020

The NO_FPSIMD capability is defined with scope SYSTEM, which implies
that the "absence" of FP/SIMD on at least one CPU is detected only
after all the SMP CPUs are brought up. However, we use the status
of this capability for every context switch. So, let us change
the scope to LOCAL_CPU to allow the detection of this capability
as and when the first CPU without FP is brought up.

Also, the current type allows hotplugged CPU to be brought up without
FP/SIMD when all the current CPUs have FP/SIMD and we have the userspace
up. Fix both of these issues by changing the capability to

Fixes: 82e0191a1aa11abf ("arm64: Support systems without FP/ASIMD")
Cc: Will Deacon <will at kernel.org>
Cc: Mark Rutland <mark.rutland at arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas at arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose at arm.com>
 arch/arm64/kernel/cpufeature.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index 1154f2d47b4b..7c373722f692 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -1428,7 +1428,7 @@ static const struct arm64_cpu_capabilities arm64_features[] = {
 		/* FP/SIMD is not implemented */
 		.capability = ARM64_HAS_NO_FPSIMD,
 		.min_field_value = 0,
 		.matches = has_no_fpsimd,

More information about the linux-arm-kernel mailing list