On Thu, Jul 02, 2015 at 06:56:00PM +0200, Philippe Gerum wrote:
> On 07/02/2015 06:49 PM, Gilles Chanteperdrix wrote:
> > On Thu, Jul 02, 2015 at 06:44:06PM +0200, Jan Kiszka wrote:
> >> On 2015-07-02 18:30, Philippe Gerum wrote:
> >>> On 07/02/2015 05:39 PM, Jan Kiszka wrote:
> >>>> On 2015-07-02 17:24, Philippe Gerum wrote:
> >>>>> On 07/02/2015 05:20 PM, git repository hosting wrote:
> >>>>>> Module: xenomai-jki
> >>>>>> Branch: for-forge
> >>>>>> Commit: 99736c29a21a5e5536f8db9e580fd11cdb0eb0f2
> >>>>>> URL:
> >>>>>> http://git.xenomai.org/?p=xenomai-jki.git;a=commit;h=99736c29a21a5e5536f8db9e580fd11cdb0eb0f2
> >>>>>>
> >>>>>> Author: Jan Kiszka <[email protected]>
> >>>>>> Date: Thu Jul 2 17:12:39 2015 +0200
> >>>>>>
> >>>>>> cobalt/kernel: Remove unused mode parameter from COBALT_SYSCALL
> >>>>>
> >>>>> We want to keep this. At some point, maybe, we will be able to use this
> >>>>> information to instrument the code with calling context guards, or as
> >>>>> the source of the mode data in the syscall table. Today, it's at least
> >>>>> useful inline documentation, without having to browse the table.
> >>>>
> >>>> This only makes sense when cobalt_sysmodes can be generated from it.
> >>>> Currently it isn't, and I bet there are already plenty of
> >>>> inconsistencies, minimizing the value captured via COBALT_SYSCALL
> >>>> massively. So we should either get rid of cobalt_sysmodes or of that
> >>>> parameter.
> >>>>
> >>>
> >>> "currently" is the point. If you feel implementing either aspects, i.e.
> >>> automatic tagging of the current context when traversing a cobalt call
> >>> based on the mode in the syscall macro, or generating the table data
> >>> based on the info, please do. If you feel fixing any consistency between
> >>> the two mode specs proving your bet right, please do as well. But for
> >>> now, I won't pick that commit.
> >>
> >> The approach of using COBALT_SYSCALL to define the mode only works if
> >> that is also the only place to define it. Let's see first if/how that
> >> can be achieved.
> >
> > That can be achieved by getting the macro to adding data in a
> > special section, then use that section as the syscall table with
> > linker generate symbols. A lot of stuff works like this, like the
> > init table, or glibc constructors, so, this can definitely be
> > achieved. This probably requires the I-pipe patch to modify the
> > kernel linker script, of which there are several instances (one
> > instance by arch maybe).
> >
>
> Yes. Having to fixup the linker script was the reason not to implement
> this immediately, as there could be some backward compat issues to
> address with legacy pipelines running a most recent 3x cobalt core.
The linker script uses wildcards, maybe we can use a section name in
that namespace to avoid changing the script.
--
Gilles.
https://click-hack.org
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