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From:   tedheadster <tedheadster@gmail.com>
Date:   Tue, 6 Feb 2018 17:11:16 -0500
Message-ID: <CAP8WD_ZaewC-NE4szBzU3brvNhvV9PwoVo-uDFcEMTMWVbsxQQ@mail.gmail.com>
Subject: Re: [BUG] x86 : i486 reporting to be vulnerable to Meltdown/Spectre_V1/Spectre_V2
To:     David Woodhouse <dwmw2@infradead.org>
Cc:     Guenter Roeck <linux@roeck-us.net>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Hugh Dickins <hughd@google.com>, dave.hansen@linux.intel.com,
        jikos@kernel.org, Borislav Petkov <bp@alien8.de>,
        Kees Cook <keescook@chromium.org>,
        Jamie Iles <jamie@jamieiles.com>, eduval@amazon.com,
        labbott@redhat.com, Rik van Riel <riel@surriel.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        linux-kernel@vger.kernel.org
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On Tue, Feb 6, 2018 at 3:54 PM, David Woodhouse <dwmw2@infradead.org> wrote:
> On Tue, 2018-02-06 at 15:45 -0500, tedheadster wrote:
>>
>> If that is correct (and I might be wrong), then I am up to date and I
>> am still getting the following in /proc/cpuinfo on my Pentium 4M i686:
>>
>> bugs  : cpu_meltdown spectre_v1 spectre_v2
>
> That's expected for now. The CPUs we exempt are as follows:
>
> static const __initdata struct x86_cpu_id cpu_no_speculation[] = {
>         { X86_VENDOR_INTEL,     6, INTEL_FAM6_ATOM_CEDARVIEW,   X86_FEATURE_ANY },
>         { X86_VENDOR_INTEL,     6, INTEL_FAM6_ATOM_CLOVERVIEW,  X86_FEATURE_ANY },
>         { X86_VENDOR_INTEL,     6, INTEL_FAM6_ATOM_LINCROFT,    X86_FEATURE_ANY },
>         { X86_VENDOR_INTEL,     6, INTEL_FAM6_ATOM_PENWELL,     X86_FEATURE_ANY },
>         { X86_VENDOR_INTEL,     6, INTEL_FAM6_ATOM_PINEVIEW,    X86_FEATURE_ANY },
>         { X86_VENDOR_CENTAUR,   5 },
>         { X86_VENDOR_INTEL,     5 },
>         { X86_VENDOR_NSC,       5 },
>         { X86_VENDOR_ANY,       4 },
>         {}
> };
>
> Alan is going to improve that list, but your Pentium 4 isn't on it yet.
>
> The bugs went away on the 486 though, right?

Okay, recompiled for the i486 and it reports no bugs.

As for the i686, it is really a "Mobile Pentium 4 HT" Prescott series
(https://ark.intel.com/products/27368/Mobile-Intel-Pentium-4-Processor-532-supporting-HT-Technology-1M-Cache-3_06-GHz-533-MHz-FSB).
Does that make it a 'speculative execution' processor?

Thank you for the help and I'll test more of the museum pieces.

- Matthew