Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Message-ID: <a40c2a60e42b5fdff46275ca42f3e7276bf11258.camel@intel.com>
Subject: Re: [RFC PATCH v6 08/11] x86: Insert endbr32/endbr64 to vDSO
From:   Yu-cheng Yu <yu-cheng.yu@intel.com>
To:     Andy Lutomirski <luto@amacapital.net>
Cc:     X86 ML <x86@kernel.org>, "H. Peter Anvin" <hpa@zytor.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>,
        LKML <linux-kernel@vger.kernel.org>,
        "open list:DOCUMENTATION" <linux-doc@vger.kernel.org>,
        Linux-MM <linux-mm@kvack.org>,
        linux-arch <linux-arch@vger.kernel.org>,
        Linux API <linux-api@vger.kernel.org>,
        Arnd Bergmann <arnd@arndb.de>,
        Balbir Singh <bsingharora@gmail.com>,
        Cyrill Gorcunov <gorcunov@gmail.com>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        Eugene Syromiatnikov <esyr@redhat.com>,
        Florian Weimer <fweimer@redhat.com>,
        "H. J. Lu" <hjl.tools@gmail.com>, Jann Horn <jannh@google.com>,
        Jonathan Corbet <corbet@lwn.net>,
        Kees Cook <keescook@chromium.org>,
        Mike Kravetz <mike.kravetz@oracle.com>,
        Nadav Amit <nadav.amit@gmail.com>,
        Oleg Nesterov <oleg@redhat.com>, Pavel Machek <pavel@ucw.cz>,
        Peter Zijlstra <peterz@infradead.org>,
        Randy Dunlap <rdunlap@infradead.org>,
        "Ravi V. Shankar" <ravi.v.shankar@intel.com>,
        "Shanbhogue, Vedvyas" <vedvyas.shanbhogue@intel.com>
Date:   Mon, 19 Nov 2018 14:43:31 -0800
In-Reply-To: <CALCETrW9ABDotyM020V147+kuizpTRJUAANn-6kUt6-h0Qn0og@mail.gmail.com>
References: <20181119214934.6174-1-yu-cheng.yu@intel.com>
         <20181119214934.6174-9-yu-cheng.yu@intel.com>
         <CALCETrW9ABDotyM020V147+kuizpTRJUAANn-6kUt6-h0Qn0og@mail.gmail.com>
Content-Type: text/plain; charset="UTF-8"
Mime-Version: 1.0
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Mon, 2018-11-19 at 14:17 -0800, Andy Lutomirski wrote:
> On Mon, Nov 19, 2018 at 1:55 PM Yu-cheng Yu <yu-cheng.yu@intel.com> wrote:
> > 
> > From: "H.J. Lu" <hjl.tools@gmail.com>
> > 
> > When Intel indirect branch tracking is enabled, functions in vDSO which
> > may be called indirectly must have endbr32 or endbr64 as the first
> > instruction.  Compiler must support -fcf-protection=branch so that it
> > can be used to compile vDSO.
> > 
> > Signed-off-by: H.J. Lu <hjl.tools@gmail.com>
> > ---
> >  arch/x86/entry/vdso/.gitignore        |  4 ++++
> >  arch/x86/entry/vdso/Makefile          | 12 +++++++++++-
> >  arch/x86/entry/vdso/vdso-layout.lds.S |  1 +
> >  3 files changed, 16 insertions(+), 1 deletion(-)
> > 
> > diff --git a/arch/x86/entry/vdso/.gitignore b/arch/x86/entry/vdso/.gitignore
> > index aae8ffdd5880..552941fdfae0 100644
> > --- a/arch/x86/entry/vdso/.gitignore
> > +++ b/arch/x86/entry/vdso/.gitignore
> > @@ -5,3 +5,7 @@ vdso32-sysenter-syms.lds
> >  vdso32-int80-syms.lds
> >  vdso-image-*.c
> >  vdso2c
> > +vclock_gettime.S
> > +vgetcpu.S
> > +vclock_gettime.asm
> > +vgetcpu.asm
> 
> 
> What's this hunk about?

We used to allow using non-CET capable BINUTILS and the Makefile would create
these.  I will remove them from the patch.

Yu-cheng