Re: [RFC PATCH v6 08/11] x86: Insert endbr32/endbr64 to vDSO

[Yu-cheng Yu <yu-cheng.yu@intel.com>]

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