Kernel-space ctypes.h support?

Joel Sherrill joel at rtems.org
Fri Sep 14 00:13:05 UTC 2018


On Thu, Sep 13, 2018, 5:40 PM Chris Johns <chrisj at rtems.org> wrote:

> On 14/09/2018 02:30, Joel Sherrill wrote:
> > On Thu, Sep 13, 2018, 10:34 AM Sebastian Huber
> > <sebastian.huber at embedded-brains.de <mailto:
> sebastian.huber at embedded-brains.de>>
> > wrote:
> >     ----- Am 13. Sep 2018 um 14:07 schrieb joel joel at rtems.org
> >     <mailto:joel at rtems.org>:
> >
> >     > On Thu, Sep 13, 2018, 3:28 AM Sebastian Huber <
> >     > sebastian.huber at embedded-brains.de
> >     <mailto:sebastian.huber at embedded-brains.de>> wrote:
> >     >
> >     >> Hello,
> >     >>
> >     >> I test currently the tqm8xx BSP which worked fine until RTEMS 5.
> The
> >     >> problem is that this BSP uses strtoul() to get some system
> configuration
> >     >> parameters from the boot loader. The Newlib used by RTEMS 5 has
> now
> >     >> support for C locales in strtoul(). The C locale support needs an
> >     >> executing thread with a valid Newlib reentrancy structure. This is
> >     >> definitely not the case during bsp_start().
> >     >>
> >     >
> >     > Why do we now longer have a global reentrancy structure to fall
> back on?
> >
> >     I think having a global reentrancy as a fall back just for the
> lowest level
> >     system start without an idle thread is a bit of overkill.
> >
> >     The heavy weight C local support which was recently introduced in
> Newlib is
> >     not really the right thing for the embedded systems I know.  There
> were
> >     several complaints about this on the Newlib mailing list as well.
> The root
> >     cause for this is the C standard. So, basically the C standard
> strtoul() is
> >     unsuitable for embedded systems. The FreeBSD (sys/kern/strtoul.c)
> and Linux
> >     (lib/kstrtox.c) kernel have their own implementations.
> >
> >
> > FWIW the FACE Technical Standard does not include wide characters in ANY
> profile
> > as of Edition 3.0. None of the RTOS vendors knew of any avionics users.
> It
> > wasn't viewed as a necessary feature. We could consider disabling it by
> default.
> >
>
> Is this something we could ot would want to control with newlib via a
> config option?
>

We don't turn on locale for h8, m32c and maybe not epiphany. I am pretty
sure.it is an option. And should be a documented RSB option to turn it back
on. Should be a size savings for most users.

>
> Chris
>
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