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From: Greg KH <gregkh@linuxfoundation.org>
To: Evalds Iodzevics <evalds.iodzevics@gmail.com>
Cc: linux-kernel@vger.kernel.org, tglx@linutronix.de,
	ben@decadent.org.uk, bp@suse.de, stable@vger.kernel.org
Subject: Re: [PATCH v2] x86/microcode/intel: replace sync_core() with native_cpuid_reg(eax)
Date: Wed, 22 Apr 2020 10:27:41 +0200	[thread overview]
Message-ID: <20200422082741.GA3017981@kroah.com> (raw)
In-Reply-To: <20200422081759.1632-1-evalds.iodzevics@gmail.com>

On Wed, Apr 22, 2020 at 11:17:59AM +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@gmail.com>
> Cc: stable@vger.kernel.org
> ---
>  arch/x86/include/asm/microcode_intel.h | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)

Thanks, much better, now queued up.

greg k-h

  reply	other threads:[~2020-04-22  8:27 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-22  8:17 [PATCH v2] x86/microcode/intel: replace sync_core() with native_cpuid_reg(eax) Evalds Iodzevics
2020-04-22  8:27 ` Greg KH [this message]
  -- strict thread matches above, loose matches on Subject: below --
2020-04-20 12:00 [PATCH] " Evalds Iodzevics
2020-04-21  8:53 ` [PATCH v2] " Evalds Iodzevics
2020-04-21  5:59   ` Greg KH
2020-04-21  6:41     ` Evalds Iodzevics
2020-04-21  7:19       ` Greg KH

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