Normally context switches happen in mi_switch() but there are 3 cases
where a switch happens outside. Cleanup these code paths and make the
machine independent.

- when a process forks (fork, tfork, kthread), the new proc needs to
somehow be scheduled for the first time. This is done by proc_trampoline.
Since proc_trampoline is machine dependent assembler code change
the MP specific proc_trampoline_mp() to proc_trampoline_mi() and make
sure it is now always called.
- cpu_hatch: when booting APs the code needs to jump to the first proc
running on that CPU. This should be the idle thread for that CPU.
- sched_exit: when a proc exits it needs to switch away from itself and
then instruct the reaper to clean up the rest. This is done by switching
to the idle loop.

Since the last two cases require a context switch to the idle proc factor
out the common code to sched_toidle() and use it in those places.

Tested by many on all archs.
OK miod@ mpi@ cheloha@

Convert KVA allocation to km_alloc(9).

ok deraadt@, mpi@

b_saveaddr has a type of void * use NULL not 0

Fix typo in comments: s/return/returns/ in "a function that never return."

Split up fork1():
- FORK_THREAD handling is a totally separate function, thread_fork(),
that is only used by sys___tfork() and which loses the flags, func,
arg, and newprocp parameters and gains tcb parameter to guarantee
the new thread's TCB is set before the creating thread returns
- fork1() loses its stack and tidptr parameters
Common bits factor out:
- struct proc allocation and initialization moves to thread_new()
- maxthread handling moves to fork_check_maxthread()
- setting the new thread running moves to fork_thread_start()
The MD cpu_fork() function swaps its unused stacksize parameter for
a tcb parameter.

luna88k testing by aoyama@, alpha testing by dlg@
ok mpi@

emul_native is only used for kernel threads which can't dump core, so
delete coredump_trad(), uvm_coredump(), cpu_coredump(), struct md_coredump,
and various #includes that are superfluous.

This leaves compat_linux processes without a coredump callback. If that
ability is desired, someone should update it to use coredump_elf32() and
verify the results...

ok kettenis@

Replace a plethora of historical protection options with just
PROT_NONE, PROT_READ, PROT_WRITE, and PROT_EXEC from mman.h.
PROT_MASK is introduced as the one true way of extracting those bits.
Remove UVM_ADV_* wrapper, using the standard names.
ok doug guenther kettenis

cpu_coredump() also needs to invoke vn_rdwr() without IO_NODELOCKED; only
affects a.out binaries' core dumps.

Use uvm_km_valloc_prefer_wait() instead of uvm_km_valloc_wait() in vmapbuf().

ok art@

pagemove() is no longer used.

Move landisk to hardware floating point. At the moment the FPU context is
always saved upon context switches, as FPU registers are heavily used for
long long computations (don't ask). Gcc default to -m4.

Credits to drahn@ otto@ and deraadt@ for feedback and help testing.

Upgrade procedure if you don't want to use the damn snapshots:
- build and install new kernel, reboot off it
- build new gcc, do not install it yet
- make includes
- install new gcc
- build and install lib/csu and lib/libc
- make build

sorry miod, but this version locks the machine up rather fast

pagemove() this time without an accidental line removal

backout pagemove() diff; does not work

A less awkward pagemove() implementation.

Fix a couple of comments.

mdproc has to be initialised

branches: 1.1.1;
Initial revision

Convert KVA allocation to km_alloc(9).

ok deraadt@, mpi@

b_saveaddr has a type of void * use NULL not 0

Fix typo in comments: s/return/returns/ in "a function that never return."

Split up fork1():
- FORK_THREAD handling is a totally separate function, thread_fork(),
that is only used by sys___tfork() and which loses the flags, func,
arg, and newprocp parameters and gains tcb parameter to guarantee
the new thread's TCB is set before the creating thread returns
- fork1() loses its stack and tidptr parameters
Common bits factor out:
- struct proc allocation and initialization moves to thread_new()
- maxthread handling moves to fork_check_maxthread()
- setting the new thread running moves to fork_thread_start()
The MD cpu_fork() function swaps its unused stacksize parameter for
a tcb parameter.

luna88k testing by aoyama@, alpha testing by dlg@
ok mpi@

emul_native is only used for kernel threads which can't dump core, so
delete coredump_trad(), uvm_coredump(), cpu_coredump(), struct md_coredump,
and various #includes that are superfluous.

This leaves compat_linux processes without a coredump callback. If that
ability is desired, someone should update it to use coredump_elf32() and
verify the results...

ok kettenis@

Replace a plethora of historical protection options with just
PROT_NONE, PROT_READ, PROT_WRITE, and PROT_EXEC from mman.h.
PROT_MASK is introduced as the one true way of extracting those bits.
Remove UVM_ADV_* wrapper, using the standard names.
ok doug guenther kettenis

cpu_coredump() also needs to invoke vn_rdwr() without IO_NODELOCKED; only
affects a.out binaries' core dumps.

Use uvm_km_valloc_prefer_wait() instead of uvm_km_valloc_wait() in vmapbuf().

ok art@

pagemove() is no longer used.

Move landisk to hardware floating point. At the moment the FPU context is
always saved upon context switches, as FPU registers are heavily used for
long long computations (don't ask). Gcc default to -m4.

Credits to drahn@ otto@ and deraadt@ for feedback and help testing.

Upgrade procedure if you don't want to use the damn snapshots:
- build and install new kernel, reboot off it
- build new gcc, do not install it yet
- make includes
- install new gcc
- build and install lib/csu and lib/libc
- make build

sorry miod, but this version locks the machine up rather fast

pagemove() this time without an accidental line removal

backout pagemove() diff; does not work

A less awkward pagemove() implementation.

Fix a couple of comments.

mdproc has to be initialised

branches: 1.1.1;
Initial revision

b_saveaddr has a type of void * use NULL not 0

Fix typo in comments: s/return/returns/ in "a function that never return."

Split up fork1():
- FORK_THREAD handling is a totally separate function, thread_fork(),
that is only used by sys___tfork() and which loses the flags, func,
arg, and newprocp parameters and gains tcb parameter to guarantee
the new thread's TCB is set before the creating thread returns
- fork1() loses its stack and tidptr parameters
Common bits factor out:
- struct proc allocation and initialization moves to thread_new()
- maxthread handling moves to fork_check_maxthread()
- setting the new thread running moves to fork_thread_start()
The MD cpu_fork() function swaps its unused stacksize parameter for
a tcb parameter.

luna88k testing by aoyama@, alpha testing by dlg@
ok mpi@

emul_native is only used for kernel threads which can't dump core, so
delete coredump_trad(), uvm_coredump(), cpu_coredump(), struct md_coredump,
and various #includes that are superfluous.

This leaves compat_linux processes without a coredump callback. If that
ability is desired, someone should update it to use coredump_elf32() and
verify the results...

ok kettenis@

Replace a plethora of historical protection options with just
PROT_NONE, PROT_READ, PROT_WRITE, and PROT_EXEC from mman.h.
PROT_MASK is introduced as the one true way of extracting those bits.
Remove UVM_ADV_* wrapper, using the standard names.
ok doug guenther kettenis

cpu_coredump() also needs to invoke vn_rdwr() without IO_NODELOCKED; only
affects a.out binaries' core dumps.

Use uvm_km_valloc_prefer_wait() instead of uvm_km_valloc_wait() in vmapbuf().

ok art@

pagemove() is no longer used.

Move landisk to hardware floating point. At the moment the FPU context is
always saved upon context switches, as FPU registers are heavily used for
long long computations (don't ask). Gcc default to -m4.

Credits to drahn@ otto@ and deraadt@ for feedback and help testing.

Upgrade procedure if you don't want to use the damn snapshots:
- build and install new kernel, reboot off it
- build new gcc, do not install it yet
- make includes
- install new gcc
- build and install lib/csu and lib/libc
- make build

sorry miod, but this version locks the machine up rather fast

pagemove() this time without an accidental line removal

backout pagemove() diff; does not work

A less awkward pagemove() implementation.

Fix a couple of comments.

mdproc has to be initialised

branches: 1.1.1;
Initial revision

Fix typo in comments: s/return/returns/ in "a function that never return."

Split up fork1():
- FORK_THREAD handling is a totally separate function, thread_fork(),
that is only used by sys___tfork() and which loses the flags, func,
arg, and newprocp parameters and gains tcb parameter to guarantee
the new thread's TCB is set before the creating thread returns
- fork1() loses its stack and tidptr parameters
Common bits factor out:
- struct proc allocation and initialization moves to thread_new()
- maxthread handling moves to fork_check_maxthread()
- setting the new thread running moves to fork_thread_start()
The MD cpu_fork() function swaps its unused stacksize parameter for
a tcb parameter.

luna88k testing by aoyama@, alpha testing by dlg@
ok mpi@

emul_native is only used for kernel threads which can't dump core, so
delete coredump_trad(), uvm_coredump(), cpu_coredump(), struct md_coredump,
and various #includes that are superfluous.

This leaves compat_linux processes without a coredump callback. If that
ability is desired, someone should update it to use coredump_elf32() and
verify the results...

ok kettenis@

Replace a plethora of historical protection options with just
PROT_NONE, PROT_READ, PROT_WRITE, and PROT_EXEC from mman.h.
PROT_MASK is introduced as the one true way of extracting those bits.
Remove UVM_ADV_* wrapper, using the standard names.
ok doug guenther kettenis

cpu_coredump() also needs to invoke vn_rdwr() without IO_NODELOCKED; only
affects a.out binaries' core dumps.

Use uvm_km_valloc_prefer_wait() instead of uvm_km_valloc_wait() in vmapbuf().

ok art@

pagemove() is no longer used.

Move landisk to hardware floating point. At the moment the FPU context is
always saved upon context switches, as FPU registers are heavily used for
long long computations (don't ask). Gcc default to -m4.

Credits to drahn@ otto@ and deraadt@ for feedback and help testing.

Upgrade procedure if you don't want to use the damn snapshots:
- build and install new kernel, reboot off it
- build new gcc, do not install it yet
- make includes
- install new gcc
- build and install lib/csu and lib/libc
- make build

sorry miod, but this version locks the machine up rather fast

pagemove() this time without an accidental line removal

backout pagemove() diff; does not work

A less awkward pagemove() implementation.

Fix a couple of comments.

mdproc has to be initialised

branches: 1.1.1;
Initial revision