On Fri, 2005-01-14 at 17:42, Jan Kiszka wrote: > Hi all, > > we (an RTnet user and I) just learned that switching on CONFIG_REGPARM > in 2.6 kernel can cause troubles with RTAI 3.1 (maybe earlier versions > as well) and with RTnet (likely all releases) with respect to LXRT > functions on x86. While the LXRT dispatcher pushes all arguments on the > stack, handler functions expect them in registers if CONFIG_REGPARM is > on and the number of arguments does not exceed 3. The user reported that > /user/latency failed to work in this case, and also no RTnet (i.e. RTDM) > call succeeded due to messed-up arguments. > > I read some RTAI changelog about fixing the task trampolines, but all > LXRT entries, i.e. the API functions, do yet deal with it - also > verified by disassembling the user's rtai_lxrt.ko... > > For RTnet, it would not be much work to add regparm or asmlinkage > (what's the difference BTW?)
asmlinkage == regparm(0) == always use the stack to pass args. > to our rather small API, but I guess it's a > bit more work for RTAI. So, better catch and deny this kernel setup? I'm > asking before patching RTnet in case RTAI 3 (fusion doesn't suffer from > this - no LXRT) goes the latter way... > > Jan > > _______________________________________________ > Rtai-dev mailing list > [EMAIL PROTECTED] > https://mail.gna.org/listinfo/rtai-dev -- Philippe.
