linux-kernel - Re: [PATCH v2] x86/boot: Handle fpu-related and clearcpuid command line arguments earlier

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Message-ID: <20200921131005.GF5901@zn.tnic>
Date:   Mon, 21 Sep 2020 15:10:05 +0200
From:   Borislav Petkov <bp@...en8.de>
To:     Mike Hommey <mh@...ndium.org>
Cc:     x86@...nel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] x86/boot: Handle fpu-related and clearcpuid command
 line arguments earlier

On Mon, Sep 21, 2020 at 07:00:36AM +0900, Mike Hommey wrote:
> FPU initialization handles them currently. However, in the case of
> clearcpuid, some other early initialization code may check for features
> before the FPU initialization code is called. Handling the argument
> earlier allows the command line to influence those early
> initializations.
> 
> Signed-off-by: Mike Hommey <mh@...ndium.org>
> ---
>  arch/x86/kernel/cpu/common.c | 41 ++++++++++++++++++++++++++++++++++++
>  arch/x86/kernel/fpu/init.c   | 41 ------------------------------------
>  2 files changed, 41 insertions(+), 41 deletions(-)
> 
> diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
> index c5d6f17d9b9d..5e2e4d3621bd 100644
> --- a/arch/x86/kernel/cpu/common.c
> +++ b/arch/x86/kernel/cpu/common.c
> @@ -23,6 +23,7 @@
>  #include <linux/syscore_ops.h>
>  #include <linux/pgtable.h>
>  
> +#include <asm/cmdline.h>
>  #include <asm/stackprotector.h>
>  #include <asm/perf_event.h>
>  #include <asm/mmu_context.h>
> @@ -1220,6 +1221,45 @@ static void detect_nopl(void)
>  #endif
>  }
>  
> +/*
> + * We parse cpu parameters early because early_identify_cpu() is executed
> + * before parse_early_param().
> + */
> +static void __init cpu__init_parse_early_param(void)

Yeah, let's call it simply "cpu_parse_early_param".

Also, I forgot to says this, sorry about that, but can you pls do your
patch ontop of tip/master:

https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git/log/

because there are other changes in that area and your patch as is,
doesn't apply.

Thx.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette