diff options
| author | Suzuki K Poulose <suzuki.poulose@arm.com> | 2020-01-13 23:30:18 +0000 |
|---|---|---|
| committer | Will Deacon <will@kernel.org> | 2020-01-14 17:11:21 +0000 |
| commit | 0cd82feb017e282b29e725801b7c90da69316734 (patch) | |
| tree | 8fa671cbbfc5b22230e56e80c0b23de3b6753455 | |
| parent | b51c6ac220f77eb246e940442d970b4065c197b0 (diff) | |
| download | linux-0cd82feb017e282b29e725801b7c90da69316734.tar.bz2 | |
arm64: fpsimd: Make sure SVE setup is complete before SIMD is used
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@kernel.org>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>
| -rw-r--r-- | arch/arm64/include/asm/simd.h | 8 |
1 files changed, 6 insertions, 2 deletions
diff --git a/arch/arm64/include/asm/simd.h b/arch/arm64/include/asm/simd.h index 7434844036d3..89cba2622b79 100644 --- a/arch/arm64/include/asm/simd.h +++ b/arch/arm64/include/asm/simd.h @@ -26,6 +26,8 @@ DECLARE_PER_CPU(bool, fpsimd_context_busy); static __must_check inline bool may_use_simd(void) { /* + * We must make sure that the SVE has been initialized properly + * before using the SIMD in kernel. * fpsimd_context_busy is only set while preemption is disabled, * and is clear whenever preemption is enabled. Since * this_cpu_read() is atomic w.r.t. preemption, fpsimd_context_busy @@ -33,8 +35,10 @@ static __must_check inline bool may_use_simd(void) * migrated, and if it's clear we cannot be migrated to a CPU * where it is set. */ - return !in_irq() && !irqs_disabled() && !in_nmi() && - !this_cpu_read(fpsimd_context_busy); + return !WARN_ON(!system_capabilities_finalized()) && + system_supports_fpsimd() && + !in_irq() && !irqs_disabled() && !in_nmi() && + !this_cpu_read(fpsimd_context_busy); } #else /* ! CONFIG_KERNEL_MODE_NEON */ |