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From: Ingo Molnar <mingo-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
To: "Jonathan (Zhixiong) Zhang"
	<zjzhang-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org>
Cc: Will Deacon <will.deacon-5wv7dgnIgG8@public.gmane.org>,
	Thomas Gleixner <tglx-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org>,
	"H . Peter Anvin" <hpa-YMNOUZJC4hwAvxtiuMwx3w@public.gmane.org>,
	"linux-kernel @ vger . kernel . org"
	<linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
	"linux-efi @ vger . kernel . org"
	<linux-efi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
	Matt Fleming
	<matt.fleming-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>,
	Borislav Petkov <bp-l3A5Bk7waGM@public.gmane.org>,
	Ard Biesheuvel
	<ard.biesheuvel-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>,
	Catalin Marinas <Catalin.Marinas-5wv7dgnIgG8@public.gmane.org>,
	Matt Fleming
	<matt-mF/unelCI9GS6iBeEJttW/XRex20P6io@public.gmane.org>
Subject: Re: [PATCH 2/2] acpi, apei: use appropriate pgprot_t to map GHES memory
Date: Sat, 22 Aug 2015 11:24:29 +0200	[thread overview]
Message-ID: <20150822092429.GB18233@gmail.com> (raw)
In-Reply-To: <1439591850-29002-2-git-send-email-zjzhang-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org>


* Jonathan (Zhixiong) Zhang <zjzhang-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org> wrote:

> From: "Jonathan (Zhixiong) Zhang" <zjzhang-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org>
> 
> With ACPI APEI firmware first handling, generic hardware error
> record is updated by firmware in GHES memory region. On an arm64
> platform, firmware updates GHES memory region with uncached
> access attribute, and then Linux reads stale data from cache.

This paragraph *still* doesn't parse for me. It's not any English
I can recognize: what is a 'With ACPI APEI firmware first handling'?

> With current code, GHES memory region is mapped with PAGE_KERNEL
> based on the assumption that cache coherency of GHES memory region
> is maintained by firmware on all platforms. This assumption is
> not true for above mentioned arm64 platform.
> 
> Instead GHES memory region should be mapped with page protection type
> according to what is returned from arch_apei_get_mem_attribute().

... plus what this changelog still doesn't mention is the most important part of 
any bug fix description: how does the user notice this in practice and why does he 
care?

Thanks,

	Ingo

  parent reply	other threads:[~2015-08-22  9:24 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-08-14 22:37 [PATCH V2 1/2] arm64: apei: implement arch_apei_get_mem_attributes() Jonathan (Zhixiong) Zhang
2015-08-14 22:37 ` [PATCH 2/2] acpi, apei: use appropriate pgprot_t to map GHES memory Jonathan (Zhixiong) Zhang
     [not found]   ` <1439591850-29002-2-git-send-email-zjzhang-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org>
2015-08-17 13:13     ` Matt Fleming
     [not found]       ` <20150817131357.GB3233-mF/unelCI9GS6iBeEJttW/XRex20P6io@public.gmane.org>
2015-08-17 21:10         ` Zhang, Jonathan Zhixiong
2015-08-22  9:24     ` Ingo Molnar [this message]
     [not found]       ` <20150822092429.GB18233-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2015-08-24 18:22         ` Zhang, Jonathan Zhixiong
     [not found]           ` <55DB60FA.8050406-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org>
2015-08-25  8:59             ` Ingo Molnar
     [not found]               ` <20150825085923.GA22414-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2015-08-25 17:30                 ` Zhang, Jonathan Zhixiong
     [not found] ` <1439591850-29002-1-git-send-email-zjzhang-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org>
2015-08-17 13:05   ` [PATCH V2 1/2] arm64: apei: implement arch_apei_get_mem_attributes() Matt Fleming
     [not found]     ` <20150817130553.GA3233-mF/unelCI9GS6iBeEJttW/XRex20P6io@public.gmane.org>
2015-08-17 21:09       ` Zhang, Jonathan Zhixiong
  -- strict thread matches above, loose matches on Subject: below --
2015-09-04 13:11 [GIT PULL 0/2] EFI changes for v4.3 (part two) Matt Fleming
     [not found] ` <1441372302-23242-1-git-send-email-matt-mF/unelCI9GS6iBeEJttW/XRex20P6io@public.gmane.org>
2015-09-04 13:11   ` [PATCH 2/2] acpi, apei: Use appropriate pgprot_t to map GHES memory Matt Fleming
2015-08-25 17:27 [PATCH 2/2] acpi, apei: use " Jonathan (Zhixiong) Zhang
     [not found] ` <1440523642-31373-1-git-send-email-zjzhang-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org>
2015-09-04 11:28   ` Matt Fleming
     [not found]     ` <20150904112820.GB2737-mF/unelCI9GS6iBeEJttW/XRex20P6io@public.gmane.org>
2015-09-04 11:36       ` Ingo Molnar
2015-08-24 18:25 Jonathan (Zhixiong) Zhang
2015-08-12 16:17 [GIT PULL 0/2] EFI changes for v4.3 (part two) Matt Fleming
2015-08-12 16:17 ` [PATCH 2/2] acpi, apei: use appropriate pgprot_t to map GHES memory Matt Fleming
     [not found]   ` <1439396234-22863-3-git-send-email-matt-mF/unelCI9GS6iBeEJttW/XRex20P6io@public.gmane.org>
2015-08-13  8:19     ` Ingo Molnar
     [not found]       ` <20150813081917.GA14610-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2015-08-13  9:24         ` Matt Fleming
     [not found]           ` <20150813092432.GA2797-mF/unelCI9GS6iBeEJttW/XRex20P6io@public.gmane.org>
2015-08-13 11:14             ` Will Deacon
     [not found]               ` <20150813111422.GE10280-5wv7dgnIgG8@public.gmane.org>
2015-08-14 19:09                 ` Zhang, Jonathan Zhixiong

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