linux-kernel - Re: [PATCH v8 3/3] x86, mce: Add __mcsafe

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Message-ID: <CALCETrUoOsh2BHYcOOQ3uh1rqnXdyf-OCGf9mnCn+yGDibv4iQ@mail.gmail.com>
Date:	Mon, 11 Jan 2016 16:30:19 -0800
From:	Andy Lutomirski <luto@...capital.net>
To:	"Luck, Tony" <tony.luck@...el.com>
Cc:	linux-nvdimm <linux-nvdimm@...1.01.org>,
	Dan Williams <dan.j.williams@...el.com>,
	Borislav Petkov <bp@...en8.de>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Robert <elliott@....com>, Ingo Molnar <mingo@...nel.org>,
	"linux-mm@...ck.org" <linux-mm@...ck.org>, X86 ML <x86@...nel.org>
Subject: Re: [PATCH v8 3/3] x86, mce: Add __mcsafe_copy()

On Mon, Jan 11, 2016 at 4:26 PM, Luck, Tony <tony.luck@...el.com> wrote:
> On Fri, Jan 08, 2016 at 05:49:30PM -0800, Andy Lutomirski wrote:
>> Also, what's the sfence for?  You don't seem to be using any
>> non-temporal operations.
>
> So I deleted the "sfence" and now I just have a comment
> at the 100: label.
>
> 37:
>         shl $6,%ecx
>         lea -48(%ecx,%edx),%edx
>         jmp 100f
> 38:
>         shl $6,%ecx
>         lea -56(%ecx,%edx),%edx
>         jmp 100f
> 39:
>         lea (%rdx,%rcx,8),%rdx
>         jmp 100f
> 40:
>         mov %ecx,%edx
> 100:
>         /* %rax set the fault number in fixup_exception() */
>         ret
>
> Should I just change all the "jmp 100f" into "ret"?  There
> aren't any tools that will be confused that the function
> has 10 returns, are there?
>

Given that gcc does that too, it should be fine.

--Andy\