this change is in preparation for amd64. the systab calling
convention was also changed to return uintptr (as segattach
returns a pointer) and the arguments are now passed as
va_list which handles amd64 arguments properly (all arguments
are passed in 64bit quantities on the stack, tho the upper
part will not be initialized when the element is smaller
than 8 bytes).
this is partial. xalloc needs to be converted in the future.
dont spam the console with qfull warnings. this makes things worse.
handle loopback packets as stated in the comment. we call etheriq()
with fromwire=1 for loopback packets so etheriq() can pass the packet
on (without copying) or free it. dont inhibit interrupts while calling
etheriq(). etheriq() can safely be called from process and interrupt
context. it is unclear what this was supposed to fix and testing didnt
seem to have any odd effects.
the kernel uses fixed area (TSTKTOP, TSTKSIZ) of the address
space to temporarily map the new stack segment for exec. for
386 and arm, this area was right below the stack segment which
has the problem that the program can map arbitrary segments
there (even readonly).
alpha and ppc dont have this problem as they map the temporary
exec stack *above* the user reachable stack segement and segattach
prevents one from mapping anything above or overlaping the stack.
lots of arch code assumes USTKTOP being the end of userspace
address space and changing this to TSTKTOP would work, but results
in lots of hard to test changes.
instead, we'r going to map the temporary stack programmatically
finding a hole in the address space where to map it. we also lift
the size limitation for arguments and allow arguments to fill
the whole new stack segement.
the TSTKTOP and TSTKSIZ are not used anymore so they where removed.
references:
http://9fans.net/archive/2013/03/203http://9fans.net/archive/2013/03/202http://9fans.net/archive/2013/03/197http://9fans.net/archive/2013/03/195http://9fans.net/archive/2013/03/181
