From mboxrd@z Thu Jan  1 00:00:00 1970
From: Peter Zijlstra <peterz@infradead.org>
Subject: Re: [PATCH] x86/cpufeature: guard asm_volatile_goto usage with
 CC_HAVE_ASM_GOTO
Date: Sat, 14 Apr 2018 12:11:12 +0200
Message-ID: <20180414101112.GX4064@hirez.programming.kicks-ass.net>
References: <20180410204259.3981586-1-yhs@fb.com>
 <20180410210716.GI4082@hirez.programming.kicks-ass.net>
 <552d5866-912e-afde-f25a-77ae8390816d@fb.com>
 <20180413181924.GT4064@hirez.programming.kicks-ass.net>
 <a65f6542-8754-ea84-d1bf-076349b6b288@fb.com>
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Cc: Yonghong Song <yhs@fb.com>, mingo@kernel.org, daniel@iogearbox.net,
        linux-kernel@vger.kernel.org, x86@kernel.org, kernel-team@fb.com,
        Thomas Gleixner <tglx@linutronix.de>,
        netdev <netdev@vger.kernel.org>,
        Jesper Dangaard Brouer <brouer@redhat.com>
To: Alexei Starovoitov <ast@fb.com>
Return-path: <linux-kernel-owner@vger.kernel.org>
Content-Disposition: inline
In-Reply-To: <a65f6542-8754-ea84-d1bf-076349b6b288@fb.com>
Sender: linux-kernel-owner@vger.kernel.org
List-Id: netdev.vger.kernel.org

On Fri, Apr 13, 2018 at 01:42:14PM -0700, Alexei Starovoitov wrote:
> On 4/13/18 11:19 AM, Peter Zijlstra wrote:
> > On Tue, Apr 10, 2018 at 02:28:04PM -0700, Alexei Starovoitov wrote:
> > > Instead of
> > > #ifdef CC_HAVE_ASM_GOTO
> > > we can replace it with
> > > #ifndef __BPF__
> > > or some other name,
> > 
> > I would prefer the BPF specific hack; otherwise we might be encouraging
> > people to build the kernel proper without asm-goto.
> > 
> 
> I don't understand this concern.

The thing is; this will be a (temporary) BPF specific hack. Hiding it
behind something that looks 'normal' (CC_HAVE_ASM_GOTO) is just not
right.