linux-kernel - Re: [PATCH v2 1/2] x86/fpu: Extend kernel_fpu_begin

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Date: Wed, 08 May 2024 15:00:18 +0200
From: Thomas Gleixner <tglx@...utronix.de>
To: "Chang S. Bae" <chang.seok.bae@...el.com>, linux-kernel@...r.kernel.org
Cc: x86@...nel.org, platform-driver-x86@...r.kernel.org, mingo@...hat.com,
 bp@...en8.de, dave.hansen@...ux.intel.com, hdegoede@...hat.com,
 ilpo.jarvinen@...ux.intel.com, tony.luck@...el.com, ashok.raj@...el.com,
 jithu.joseph@...el.com, chang.seok.bae@...el.com
Subject: Re: [PATCH v2 1/2] x86/fpu: Extend kernel_fpu_begin_mask() to
 initialize AMX state

On Tue, May 07 2024 at 16:53, Chang S. Bae wrote:
> diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c
> index 1209c7aebb21..04cc6f14ca42 100644
> --- a/arch/x86/kernel/fpu/core.c
> +++ b/arch/x86/kernel/fpu/core.c
> @@ -440,6 +440,9 @@ void kernel_fpu_begin_mask(unsigned int kfpu_mask)
>  
>  	if (unlikely(kfpu_mask & KFPU_387) && boot_cpu_has(X86_FEATURE_FPU))
>  		asm volatile ("fninit");
> +
> +	if (unlikely(kfpu_mask & KFPU_AMX) && boot_cpu_has(X86_FEATURE_AMX_TILE))

  cpu_feature_enabled() please

> +		restore_fpregs_from_fpstate(&init_fpstate, XFEATURE_MASK_XTILE);
>  }
>  EXPORT_SYMBOL_GPL(kernel_fpu_begin_mask);