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Date: Tue, 24 Feb 2015 21:36:36 +0100
From: Borislav Petkov <bp@alien8.de>
To: Denys Vlasenko <vda.linux@googlemail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>,
        Andy Lutomirski <luto@amacapital.net>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Steven Rostedt <rostedt@goodmis.org>, Ingo Molnar <mingo@kernel.org>,
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        Frederic Weisbecker <fweisbec@gmail.com>,
        Alexei Starovoitov <ast@plumgrid.com>, Will Drewry <wad@chromium.org>,
        Kees Cook <keescook@chromium.org>, X86 ML <x86@kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 1/4] x86: entry.S: tidy up several suboptimal insns
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On Tue, Feb 24, 2015 at 09:13:03PM +0100, Denys Vlasenko wrote:
> They aren't equal.  $1 and $2 in two lowest bits will also
> be interpreted as "userspace" here. "Equal to $3" sends
> a wrong message here to a human reading the code,
> the code doesn't test for CPL=3, it tests for any nonzero CPL.

Doh, of course.

I was going to propose to make it even more explicit:

	andb $3, CS(%rsp)...

but that's destructive.

So yours makes it less misleading, actually. To me at least and
obviously.

:-)

-- 
Regards/Gruss,
    Boris.

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