linux-kernel - Re: [PATCH v4 22/22] x86/fpu/xstate: Introduce boot-parameters to control state component support

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Message-ID: <20210326181641.GD27507@zn.tnic>
Date:   Fri, 26 Mar 2021 19:17:17 +0100
From:   Borislav Petkov <bp@...en8.de>
To:     Len Brown <lenb@...nel.org>
Cc:     Andy Lutomirski <luto@...nel.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        "Chang S. Bae" <chang.seok.bae@...el.com>,
        Ingo Molnar <mingo@...nel.org>, X86 ML <x86@...nel.org>,
        "Brown, Len" <len.brown@...el.com>,
        Dave Hansen <dave.hansen@...el.com>,
        "Liu, Jing2" <jing2.liu@...el.com>,
        "Ravi V. Shankar" <ravi.v.shankar@...el.com>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Linux Documentation List <linux-doc@...r.kernel.org>
Subject: Re: [PATCH v4 22/22] x86/fpu/xstate: Introduce boot-parameters to
 control state component support

On Fri, Mar 26, 2021 at 01:53:47PM -0400, Len Brown wrote:
> At Dave's suggestion, we had a 64 *KB* sanity check on this path.
> Boris forced us to remove it, because we could not tell him
> how we chose the number 64.

The only 64 I can remember is

#define XSTATE_BUFFER_MAX_BYTES              (64 * 1024)

What does an arbitrary number have to do with signal handling and
pushing a fat frame on the sigaltstack?

-- 
Regards/Gruss,
    Boris.

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