[PATCH 5/5] arm64: neon: Remove support for nested or hardirq kernel-mode NEON

[Ard Biesheuvel]

On 7 August 2017 at 12:23, Catalin Marinas <catalin.marinas at arm.com> wrote:
> On Thu, Aug 03, 2017 at 05:23:23PM +0100, Dave P Martin wrote:
>> diff --git a/arch/arm64/include/asm/simd.h b/arch/arm64/include/asm/simd.h
>> index 96959b5..5a1a927 100644
>> --- a/arch/arm64/include/asm/simd.h
>> +++ b/arch/arm64/include/asm/simd.h
>> @@ -9,15 +9,46 @@
>>  #ifndef __ASM_SIMD_H
>>  #define __ASM_SIMD_H
>>
>> +#include <linux/compiler.h>
>> +#include <linux/percpu.h>
>> +#include <linux/preempt.h>
>>  #include <linux/types.h>
>>
>> +#ifdef CONFIG_KERNEL_MODE_NEON
>> +
>> +DECLARE_PER_CPU(bool, kernel_neon_busy);
> [...]
>> @@ -233,49 +254,69 @@ void fpsimd_flush_task_state(struct task_struct *t)
>>
>>  #ifdef CONFIG_KERNEL_MODE_NEON
>>
>> -static DEFINE_PER_CPU(struct fpsimd_partial_state, hardirq_fpsimdstate);
>> -static DEFINE_PER_CPU(struct fpsimd_partial_state, softirq_fpsimdstate);
>> +DEFINE_PER_CPU(bool, kernel_neon_busy);
>
> This variable needs to be exported to modules (allmodconfig fails to
> build with these patches). Any preference for GPL vs non-GPL export?
>

It should match whatever kernel_neon_begin|end use.


> diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c
> index 138fcfaeadc1..5dde6f5961a1 100644
> --- a/arch/arm64/kernel/fpsimd.c
> +++ b/arch/arm64/kernel/fpsimd.c
> @@ -255,6 +255,7 @@ void fpsimd_flush_task_state(struct task_struct *t)
>  #ifdef CONFIG_KERNEL_MODE_NEON
>
>  DEFINE_PER_CPU(bool, kernel_neon_busy);
> +EXPORT_PER_CPU_SYMBOL_GPL(kernel_neon_busy);
>
>  /*
>   * Kernel-side NEON support functions
>
> --
> Catalin