0001-Part-1.-Add-generic-part-for-Intel-CET-enabling

[Richard Biener]

On Fri, Sep 15, 2017 at 1:12 PM, Tsimbalist, Igor V
<igor.v.tsimbalist@intel.com> wrote:
>> -----Original Message-----
>> From: Tsimbalist, Igor V
>> Sent: Tuesday, September 12, 2017 5:35 PM
>> To: 'Richard Biener' <richard.guenther@gmail.com>
>> Cc: 'gcc-patches@gcc.gnu.org' <gcc-patches@gcc.gnu.org>; Tsimbalist, Igor V
>> <igor.v.tsimbalist@intel.com>
>> Subject: RE: 0001-Part-1.-Add-generic-part-for-Intel-CET-enabling
>>
>> > -----Original Message-----
>> > From: Tsimbalist, Igor V
>> > Sent: Friday, August 18, 2017 4:43 PM
>> > To: 'Richard Biener' <richard.guenther@gmail.com>
>> > Cc: gcc-patches@gcc.gnu.org; Tsimbalist, Igor V
>> > <igor.v.tsimbalist@intel.com>
>> > Subject: RE: 0001-Part-1.-Add-generic-part-for-Intel-CET-enabling
>> >
>> > > -----Original Message-----
>> > > From: Richard Biener [mailto:richard.guenther@gmail.com]
>> > > Sent: Friday, August 18, 2017 3:53 PM
>> > > To: Tsimbalist, Igor V <igor.v.tsimbalist@intel.com>
>> > > Cc: gcc-patches@gcc.gnu.org
>> > > Subject: Re: 0001-Part-1.-Add-generic-part-for-Intel-CET-enabling
>> > >
>> > > On Fri, Aug 18, 2017 at 3:11 PM, Tsimbalist, Igor V
>> > > <igor.v.tsimbalist@intel.com> wrote:
>> > > >> -----Original Message-----
>> > > >> From: Richard Biener [mailto:richard.guenther@gmail.com]
>> > > >> Sent: Tuesday, August 15, 2017 3:43 PM
>> > > >> To: Tsimbalist, Igor V <igor.v.tsimbalist@intel.com>
>> > > >> Cc: gcc-patches@gcc.gnu.org
>> > > >> Subject: Re: 0001-Part-1.-Add-generic-part-for-Intel-CET-enabling
>> > > >>
>> > > >> On Tue, Aug 1, 2017 at 10:56 AM, Tsimbalist, Igor V
>> > > >> <igor.v.tsimbalist@intel.com> wrote:
>> > > >> > Part#1. Add generic part for Intel CET enabling.
>> > > >> >
>> > > >> > The spec is available at
>> > > >> >
>> > > >> > https://software.intel.com/sites/default/files/managed/4d/2a/co
>> > > >> > nt ro l-f low-enforcement-technology-preview.pdf
>
> <..skipped..>
>
>> > > >> I think 'notrack' is somewhat unspecific of a name, what
>> > > >> prevented you to use 'nocet'?
>> > > >
>> > > > Actually it's specific. The HW will have a prefix with exactly
>> > > > this name and
>> > > the same meaning. And I think, what is more important, 'track/notrack'
>> > > gives better semantic for a user. CET is a name bound with Intel
>> > > specific technology.
>> > >
>> > > But 'tracking' something is quite unspecific.  Tracking for what?
>> > > 'no_verify_cf' (aka do not verify control flow) maybe?
>> >
>> > The name just  has to suggest the right semantic. 'no_verify_cf' is
>> > good, let's use it unless different name appears.
>> I have renamed all newly introduced function and macro names to use
>> 'noverify_cf'. But I still keep the attribute name as 'notrack'. Historically the
>> attribute name follows the public CET specification, which uses 'no-track
>> prefix' wording. Is it ok to keep such attribute name?
>
> Here is an updated proposal about option name and attribute name.
>
> The new option has values to let a user to choose what control-flow protection to activate.
>
> -fcf-protection=[full|branch|return|none]
>   branch - do control-flow protection for indirect jumps and calls
>   return - do control-flow protection for function returns
>   full - alias to specify both branch + return
>   none - turn off protection. This value is needed when/if cf-protection is turned on by default by driver in future
>
> Attribute name is the most tough one. Here are several names to evaluate: 'nocf_verify' or 'nocf_check', or to be more specific and to mimic option name 'nocf_branch_verify' or 'nocf_branch_check'. I would prefer 'nocf_check' as it applies to functions and function pointers so it's definitely related to a branch and it's a smaller one.
>
> If you ok with the new proposal I'll implement it in a general parts (code, documentation and tests) and resend these patches for review.

nocf_check sounds fine to me.

Richard.

> Thanks,
> Igor
>