process context ('reaper').
From within the exiting process context:
* deactivate pmap and free vmspace while we can still block
* introduce MD cpu_lwp_free() - this cleans all MD-specific context (such
as FPU state), and is the last potentially blocking operation;
all of cpu_wait(), and most of cpu_exit(), is now folded into cpu_lwp_free()
* process is now immediatelly marked as zombie and made available for pickup
by parent; the remaining last lwp continues the exit as fully detached
* MI (rather than MD) code bumps uvmexp.swtch, cpu_exit() is now same
for both 'process' and 'lwp' exit
uvm_lwp_exit() is modified to never block; the u-area memory is now
always just linked to the list of available u-areas. Introduce (blocking)
uvm_uarea_drain(), which is called to release the excessive u-area memory;
this is called by parent within wait4(), or by pagedaemon on memory shortage.
uvm_uarea_free() is now private function within uvm_glue.c.
MD process/lwp exit code now always calls lwp_exit2() immediatelly after
switching away from the exiting lwp.
g/c now unneeded routines and variables, including the reaper kernel thread
While we are here, try to tag machine dependent functions in header files.
also transformed darwin_ppc_*_state into mach_ppc_*_state, as this is
what they really are (COMPAT_DARWIN is on the top of COMPAT_MACH, not the
other way around)
containing signal posting, kernel-exit handling and sa_upcall processing.
XXX the pc532, sparc, sparc64 and vax ports should have their
XXX userret() code rearranged to use this.
Use <powerpc/oea/bat.h> exclusively and remove <machine/bat.h> and
<powerpc/bat.h>. Remove unneeded <machine/cpufunc.h>. To insure
1:1 correspondence of <powerpc/FOO.h> to <machine/FOO.h> include
"../../powerpc/include/Makefile" in "arch/FOO/include/Makefile".
Incororpate <byte_swap.h> into <bswap.h> and then byte_swap.h
* _UC_MACHINE_PC() - access the program counter
* _UC_MACHINE_INTRV() - access the integer return value register
* _UC_MACHINE_SET_PC() - set the program counter (this requires
special handling on some platforms).
and make the stack and heap non-executable by default. the changes
fall into two basic catagories:
- pmap and trap-handler changes. these are all MD:
= alpha: we already track per-page execute permission with the (software)
PG_EXEC bit, so just have the trap handler pay attention to it.
= i386: use a new GDT segment for %cs for processes that have no
executable mappings above a certain threshold (currently the
bottom of the stack). track per-page execute permission with
the last unused PTE bit.
= powerpc/ibm4xx: just use the hardware exec bit.
= powerpc/oea: we already track per-page exec bits, but the hardware only
implements non-exec mappings at the segment level. so track the
number of executable mappings in each segment and turn on the no-exec
segment bit iff the count is 0. adjust the trap handler to deal.
= sparc (sun4m): fix our use of the hardware protection bits.
fix the trap handler to recognize text faults.
= sparc64: split the existing unified TSB into data and instruction TSBs,
and only load TTEs into the appropriate TSB(s) for the permissions.
fix the trap handler to check for execute permission.
= not yet implemented: amd64, hppa, sh5
- changes in all the emulations that put a signal trampoline on the stack.
instead, we now put the trampoline into a uvm_aobj and map that into
the process separately.
originally from openbsd, adapted for netbsd by me.
since it was write-only. When setting up a process, make sure the fake
callframes are properly linked together.
Only lower SPL when in Idle loop. Raise spl to previous level (which would
be IPL_SCHED) when exiting Idle loop. Never lower SPL anyplace else.
