* Ingo Molnar (mingo@elte.hu) wrote:

* Chris Wright [off-list ref] wrote:

quoted

Current -rt is broken when compiling with CONFIG_PARAVIRT and 
CONFIG_MCOUNT both enabled.  Because CONFIG_MCOUNT disables 
CONFIG_REGPARM, the calling convention must once again be explicit 
with fastcall.  However, this was only half-way addressed in the -rt 
patch (adding fastcall back to paravirt_ops function ptr declaration 
but not the actual function definitions) so the compiled kernel has 
caller putting stuff in registers and callee pulling things from the 
stack. Impressive how far into boot it can get despite that ;-) Thanks 
to Steven Rostedt for prodding me and starting the initial debugging.

thanks! I ran into this before and asked for the fastcalls to not be 
removed from upstream paravirt.c but to no avail it seems. It does no 
harm to anyone to keep the 'fastcall' declarations and definitions for 
places where _actual assembly code_ depends on the calling convention. 
Could someone please send this upstream-wards too?

Yes, I agree, it's actually documenting the subtlety of the calling
convention, not just noise in the source.  The upstream patch is
different, I'll sort one out.

thanks,
-chris