pmap_remove_all(): Return a boolean value to indicate the behaviour. If
true, all mappings have been removed, the pmap is totally cleared out, and
UVM can then avoid doing the work to call pmap_remove() for each map entry.
If false, either nothing has been done, or some helpful arch-specific voodoo
has taken place.

Use "__nothing" macro defined in <sys/cdefs.h> for empty pmap_update().

Suggested by pgoyette@ in PR/54869.

branches: 1.26.44;
The pmap_prefer() function grew an additional argument with the introduction
of top-down VM; fix the prototype accordingly.

switch to __USE_TOPDOWN_VM.

branches: 1.24.2; 1.24.12;
- remove simple_lock(9) and use atomic_ops(3) to account pmap reference count,
perrequest from rmind@
- while here no need to export struct pmap on sun2/sun3/sun3x

No particular problem for a week on hp300 and sun3x kernels with disabled
tcp_vtw which has been broken for a month on low memory machines.

branches: 1.23.4; 1.23.6; 1.23.10;
Export pmap_procwr() declaration only #ifdef _KERNEL.

Refactoring MD segment related definitions on m68k ports:
- move macro SEGSHIFT, NBSG, and SEGOFFSET from <machine/param.h>
to <machine/pmap.h> where they should belong
- don't use m68k_round_seg() and m68k_trunc_seg() in sun2 pmap sources
and instead define and use sun2_round_seg() and sun2_trunc_seg()
since they are quite pmap implementation dependent

Make pmap_kernel() a MI macro for struct pmap *kernel_pmap_ptr,
which is now the "API" provided by the pmap module. pmap_kernel()
remains as the syntactic sugar.

Bonus cosmetics round: move all the pmap_t pointer typedefs into
uvm_pmap.h.

Thanks to Greg Oster for providing cpu muscle for doing test builds.

branches: 1.20.6; 1.20.8;
Remove clause 3 and 4 from TNF licenses

branches: 1.19.6; 1.19.8; 1.19.10;
Include sys/simplelock.h for the sake of pm_lock.

branches: 1.18.44; 1.18.50; 1.18.58;
Change "inline" back to "__inline" in .h files -- C99 is still too
new, and some apps compile things in C89 mode. C89 keywords stay.

As per core@.

branches: 1.17.2; 1.17.4; 1.17.6;
Remove leading __ from __(const|inline|signed|volatile) -- it is obsolete.

merge ktrace-lwp.

branches: 1.15.8;
de-__P, remove register, ansify, b* -> mem*, u_int*_t -> uint*_t.

Convert the PMAP_PREFER() macro from two arguments (offset and hint)
to four (adding size and direction).

In order for topdown uvm to be an option on ports using PMAP_PREFER,
they will need to "prefer" lower addresses if topdown is being used.
Additionally, at least one port also needs to know the size.

branches: 1.13.6; 1.13.14;
it really helps to get the stub right before cutting + pasting it 27 times.
alas, I did not. doh.

add pmap_remove_all() hook (empty on most platforms so far).

Purge vm_offset_t.

branches: 1.10.4;
Update pmap_update to now take the updated pmap as an argument.
This will allow improvements to the pmaps so that they can more easily defer expensive operations, eg tlb/cache flush, til the last possible moment.

Currently this is a no-op on most platforms, so they should see no difference.

Reviewed by Jason.

branches: 1.9.2; 1.9.4;
Added comments and fixed some macros now that I correctly
understand how to address the sun2 VME bus in the VM hardware.

replace vm_map{,_entry}_t with struct vm_map{,_entry} *.

replace {simple_,}lock{_data,}_t with struct {simple,}lock {,*}.

Garbage-collect pmap_page_index().

Undo a misguided previous change to the pmap_update() API.

Give pmap_update() an argument (a pmap_t) so that it knows which
pmap it should be updating.

#define away pmap_update() in <machine/pmap.h> so that no function
call overhead is incurred as we start sprinkling pmap_update() calls
throughout the source tree (no pmaps currently defer operations, but
we are adding the infrastructure to allow them to do so).

branches: 1.2.2;
Added a prototype for the internal function _pmap_extract_pmeg,
used by the bus_dma implementation when double-mapping pages
by hand.
Now define PMAP_OBMEM for completeness.

Added.

Use "__nothing" macro defined in <sys/cdefs.h> for empty pmap_update().

Suggested by pgoyette@ in PR/54869.

The pmap_prefer() function grew an additional argument with the introduction
of top-down VM; fix the prototype accordingly.

switch to __USE_TOPDOWN_VM.

branches: 1.24.2; 1.24.12;
- remove simple_lock(9) and use atomic_ops(3) to account pmap reference count,
perrequest from rmind@
- while here no need to export struct pmap on sun2/sun3/sun3x

No particular problem for a week on hp300 and sun3x kernels with disabled
tcp_vtw which has been broken for a month on low memory machines.

branches: 1.23.4; 1.23.6; 1.23.10;
Export pmap_procwr() declaration only #ifdef _KERNEL.

Refactoring MD segment related definitions on m68k ports:
- move macro SEGSHIFT, NBSG, and SEGOFFSET from <machine/param.h>
to <machine/pmap.h> where they should belong
- don't use m68k_round_seg() and m68k_trunc_seg() in sun2 pmap sources
and instead define and use sun2_round_seg() and sun2_trunc_seg()
since they are quite pmap implementation dependent

Make pmap_kernel() a MI macro for struct pmap *kernel_pmap_ptr,
which is now the "API" provided by the pmap module. pmap_kernel()
remains as the syntactic sugar.

Bonus cosmetics round: move all the pmap_t pointer typedefs into
uvm_pmap.h.

Thanks to Greg Oster for providing cpu muscle for doing test builds.

branches: 1.20.6; 1.20.8;
Remove clause 3 and 4 from TNF licenses

branches: 1.19.6; 1.19.8; 1.19.10;
Include sys/simplelock.h for the sake of pm_lock.

branches: 1.18.44; 1.18.50; 1.18.58;
Change "inline" back to "__inline" in .h files -- C99 is still too
new, and some apps compile things in C89 mode. C89 keywords stay.

As per core@.

branches: 1.17.2; 1.17.4; 1.17.6;
Remove leading __ from __(const|inline|signed|volatile) -- it is obsolete.

merge ktrace-lwp.

branches: 1.15.8;
de-__P, remove register, ansify, b* -> mem*, u_int*_t -> uint*_t.

Convert the PMAP_PREFER() macro from two arguments (offset and hint)
to four (adding size and direction).

In order for topdown uvm to be an option on ports using PMAP_PREFER,
they will need to "prefer" lower addresses if topdown is being used.
Additionally, at least one port also needs to know the size.

branches: 1.13.6; 1.13.14;
it really helps to get the stub right before cutting + pasting it 27 times.
alas, I did not. doh.

add pmap_remove_all() hook (empty on most platforms so far).

Purge vm_offset_t.

branches: 1.10.4;
Update pmap_update to now take the updated pmap as an argument.
This will allow improvements to the pmaps so that they can more easily defer expensive operations, eg tlb/cache flush, til the last possible moment.

Currently this is a no-op on most platforms, so they should see no difference.

Reviewed by Jason.

branches: 1.9.2; 1.9.4;
Added comments and fixed some macros now that I correctly
understand how to address the sun2 VME bus in the VM hardware.

replace vm_map{,_entry}_t with struct vm_map{,_entry} *.

replace {simple_,}lock{_data,}_t with struct {simple,}lock {,*}.

Garbage-collect pmap_page_index().

Undo a misguided previous change to the pmap_update() API.

Give pmap_update() an argument (a pmap_t) so that it knows which
pmap it should be updating.

#define away pmap_update() in <machine/pmap.h> so that no function
call overhead is incurred as we start sprinkling pmap_update() calls
throughout the source tree (no pmaps currently defer operations, but
we are adding the infrastructure to allow them to do so).

branches: 1.2.2;
Added a prototype for the internal function _pmap_extract_pmeg,
used by the bus_dma implementation when double-mapping pages
by hand.
Now define PMAP_OBMEM for completeness.

Added.