linux-kernel - Re: [PATCH v2] x86/microcode/intel: replace sync_core() with native_cpuid

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Message-ID: <CADqhmmeNd3A7Ki8SZi4j7aubm3bHDxQ-pNM6bR56geE9BwUjww@mail.gmail.com>
Date:   Tue, 21 Apr 2020 09:41:42 +0300
From:   Evalds Iodzevics <evalds.iodzevics@...il.com>
To:     Greg KH <gregkh@...uxfoundation.org>
Cc:     linux-kernel@...r.kernel.org, Thomas Gleixner <tglx@...utronix.de>,
        Ben Hutchings <ben@...adent.org.uk>
Subject: Re: [PATCH v2] x86/microcode/intel: replace sync_core() with native_cpuid_reg(eax)

On Tue, Apr 21, 2020 at 8:59 AM Greg KH <gregkh@...uxfoundation.org> wrote:
>
> On Tue, Apr 21, 2020 at 11:53:44AM +0300, Evalds Iodzevics wrote:
> > On Intel it is required to do CPUID(1) before reading the microcode
> > revision MSR. Current code in 4.4 an 4.9 relies on sync_core() to call
> > CPUID, unfortunately on 32 bit machines code inside sync_core() always
> > jumps past CPUID instruction as it depends on data structure boot_cpu_data
> > witch are not populated correctly so early in boot sequence.
> >
> > It depends on:
> > commit 5dedade6dfa2 ("x86/CPU: Add native CPUID variants returning a single
> > datum")
> >
> > This patch is for 4.4 but also should apply to 4.9
> >
> > Signed-off-by: Evalds Iodzevics <evalds.iodzevics@...il.com>
> > ---
> >  arch/x86/include/asm/microcode_intel.h | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
>
> Why are you not sending this to the stable mailing list like I have
> pointed out numerous times by sending you a link to _how_ to get a patch
> into the stable kernel trees?
>
> Again, here it is:
>     https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html
>
> Please follow that so that we can do this correctly.
>
> thanks,
>
> greg k-h
Sorry, I might sound dumb here but should i just send it to
stable@...r.kernel.org or try to tag it Cc: stable... in sign-off
area, its quite confusing for newcomer.
Thanks for patience!