linux-kernel - Re: [PATCHV3 1/3] x86, ras: Add new infrastructure for machine check fixup tables

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Date:	Mon, 21 Dec 2015 19:18:54 +0100
From:	Borislav Petkov <bp@...en8.de>
To:	Tony Luck <tony.luck@...el.com>
Cc:	Ingo Molnar <mingo@...nel.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Andy Lutomirski <luto@...nel.org>,
	Dan Williams <dan.j.williams@...el.com>, Elliott@...tnic,
	Robert <elliott@....com>, linux-kernel@...r.kernel.org,
	linux-mm@...ck.org, linux-nvdimm@...1.01.org, x86@...nel.org
Subject: Re: [PATCHV3 1/3] x86, ras: Add new infrastructure for machine check
 fixup tables

On Tue, Dec 15, 2015 at 05:29:30PM -0800, Tony Luck wrote:
> Copy the existing page fault fixup mechanisms to create a new table
> to be used when fixing machine checks. Note:
> 1) At this time we only provide a macro to annotate assembly code
> 2) We assume all fixups will in code builtin to the kernel.
> 3) Only for x86_64
> 4) New code under CONFIG_MCE_KERNEL_RECOVERY (default 'n')
> 
> Signed-off-by: Tony Luck <tony.luck@...el.com>
> ---
>  arch/x86/Kconfig                  | 10 ++++++++++
>  arch/x86/include/asm/asm.h        | 10 ++++++++--
>  arch/x86/include/asm/mce.h        | 14 ++++++++++++++
>  arch/x86/kernel/cpu/mcheck/mce.c  | 16 ++++++++++++++++
>  arch/x86/kernel/vmlinux.lds.S     |  6 +++++-
>  arch/x86/mm/extable.c             | 19 +++++++++++++++++++
>  include/asm-generic/vmlinux.lds.h | 12 +++++++-----
>  7 files changed, 79 insertions(+), 8 deletions(-)
> 
> diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
> index 96d058a87100..42d26b4d1ec4 100644
> --- a/arch/x86/Kconfig
> +++ b/arch/x86/Kconfig
> @@ -1001,6 +1001,16 @@ config X86_MCE_INJECT
>  	  If you don't know what a machine check is and you don't do kernel
>  	  QA it is safe to say n.
>  
> +config MCE_KERNEL_RECOVERY
> +	bool "Recovery from machine checks in special kernel memory copy functions"
> +	default n
> +	depends on X86_MCE && X86_64

Still no dependency on CONFIG_LIBNVDIMM.

> +	---help---
> +	  This option provides a new memory copy function mcsafe_memcpy()
> +	  that is annotated to allow the machine check handler to return
> +	  to an alternate code path to return an error to the caller instead
> +	  of crashing the system. Say yes if you have a driver that uses this.
> +

-- 
Regards/Gruss,
    Boris.

ECO tip #101: Trim your mails when you reply.
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