linux-kernel - Re: [PATCH 00/18] Pile o' entry/exit/sp0 changes

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Message-ID: <CALCETrUvCPkjystbzj+BnTe2bSnC03o+yRonYkeuUUo_T-3j=Q@mail.gmail.com>
Date:   Sat, 28 Oct 2017 00:31:35 -0700
From:   Andy Lutomirski <luto@...nel.org>
To:     Linus Torvalds <torvalds@...ux-foundation.org>
Cc:     Andy Lutomirski <luto@...nel.org>, X86 ML <x86@...nel.org>,
        Borislav Petkov <bpetkov@...e.de>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Brian Gerst <brgerst@...il.com>,
        Dave Hansen <dave.hansen@...el.com>
Subject: Re: [PATCH 00/18] Pile o' entry/exit/sp0 changes

On Thu, Oct 26, 2017 at 8:55 AM, Linus Torvalds
<torvalds@...ux-foundation.org> wrote:
>
>
> On Thu, 26 Oct 2017, Andy Lutomirski wrote:
>>
>> Here's the first "real" version of this series.  It's based on Linus'
>> tree from a couple days ago.
>
> Not seeing any problems in this series. I was hoping it would remove more
> lines of code than it adds, and it's the reverse, but that seems to be
> mostly the new push/pop stuff. I'm taking it we couldn't just replace the
> 'mov' instructions in the save/restore macros..

The problem is that I didn't quite finish the job.  v2 gets rid of the
RESTORE macros entirely.  I'll deal with SAVE some other time.

>
> I *do* ask that when we have code like this:
>
>         POP_EXTRA_REGS
>         POP_C_REGS
>         addq    $8, %rsp
>
> that "addq $8" would have a comment about what stack entry we're skipping.
>
> I *think* it's 'orig_eax', but wouldn't it be nice to say so?
>

Done.  (It was orig_ax.)

>             Linus