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Subject: Re: [PATCH 2/2] x86/asm/entry/32: Remove unnecessary optimization in stub32_clone
From: Linus Torvalds <torvalds@linux-foundation.org>
To: Josh Triplett <josh@joshtriplett.org>
Cc: Andy Lutomirski <luto@amacapital.net>,
        Denys Vlasenko <dvlasenk@redhat.com>, Ingo Molnar <mingo@kernel.org>,
        Steven Rostedt <rostedt@goodmis.org>, Borislav Petkov <bp@alien8.de>,
        "H. Peter Anvin" <hpa@zytor.com>, Oleg Nesterov <oleg@redhat.com>,
        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@vger.kernel.org" <linux-kernel@vger.kernel.org>
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On Wed, Apr 22, 2015 at 10:10 AM, Josh Triplett <josh@joshtriplett.org> wrote:
>
> I do think my two-patch HAVE_COPY_THREAD_TLS series should go in fixing
> this

Ugh, I absolutely detesrt that patch.

Don't make random crazy function signatures that depend on some config
option. That's just evil. The patch is a mess of #ifdef's and should
be shot in the head and staked with a silver stake to  make sure it
never re-appears.

Either:

 (a) make the change for every architecture

 (b) have side-by-side interfaces. With different names!

but not that disgusting "the calling conventions of these random
functions are different on different architectures and we use a config
flag to distinguish the cases".

           Linus