Messages in this thread |  | | Date | Fri, 10 Jan 2020 11:51:32 +0000 | From | Catalin Marinas <> | Subject | Re: [PATCH v2 2/7] arm64: fpsimd: Make sure SVE setup is complete before SIMD is used |
| |
On Tue, Dec 17, 2019 at 06:33:57PM +0000, Suzuki K Poulose wrote: > In-kernel users of NEON rely on may_use_simd() to check if the SIMD > can be used. However, we must initialize the SVE before SIMD can > be used. Add a sanity check to make sure that we have completed the > SVE setup before anyone uses the SIMD. > > Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> > Cc: Mark Rutland <mark.rutland@arm.com> > Cc: Will Deacon <will.deacon@arm.com> > Cc: Catalin Marinas <catalin.marinas@arm.com> > Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> > --- > Discussion here : https://lkml.kernel.org/r/20191014145204.GS27757@arm.com
Re-reading this thread, I think the conclusion was more towards having a WARN_ON in system_supports_fpsimd() (or may_use_simd()). We don't expect code to start using neon before the SMP is initialised (other than early_initcall(), the rest run after the secondary CPUs are brought up).
-- Catalin
|  |