* Count page table pages in the RSS.
* Rather than patching it up, panic if access_type has bits not in prot, as
this should now be impossible.
* Add page table reference counting, but currently disabled as it still has
some issues.
When we put a page on the collection list, we must subtract NPVPPG from the
total free count: one for each pv_entry that's free in that page, and one for
each free pv_entry in other pages that we're going to eat by moving the ones
in the page being collected.
pmap_find_pv(), pmap_clean_page() and pmap_remove_all() are only called on
managed pages, after VM initialization. Panic if this invariant is violated.
Also, panic if we try to enter a PT page through pmap_enter(), rather than
silently patching it up.
pmap_initialized is now #ifdef DIAGNOSTIC.
* Map the message buffer with access_type = VM_PROT_READ|VM_PROT_WRITE `just
because'.
* Map the file system buffers with access_type = VM_PROT_READ|VM_PROT_WRITE to
avoid possible problems with pagemove().
* Do not use VM_PROT_EXEC with either of the above.
* Map pages for /dev/mem with access_type = prot. Also, DO NOT use
pmap_kenter() for this, as we DO NOT want to lose modification information.
* Map pages in dumpsys() with VM_PROT_READ.
* Map pages in m68k mappedcopyin()/mappedcopyout() and writeback() with
access_type = prot.
* For now, bus_dma*(), pmap_map(), vmapbuf(), and similar functions still use
access_type = 0. This should probably be revisited.
emulation of managed pages. This required the following `interesting' changes:
* File system buffers must be entered with an access type of
VM_PROT_READ|VM_PROT_WRITE, so that the pages will be accessible immediately.
Otherwise we would have to teach pagemove() to update the R/M information.
Since they're never eligible for paging, the latter is overkill.
* We must insure that pages allocated before the pmap is completely set up
(that is, pages allocated early by the VM system) are not eligible for R/M
emulation, since the memory needed for this isn't available. We do this by
allocating the pmap's internal memory with uvm_pageboot_alloc(). This also
fixes an absolutely horrible hack where the pmap only worked because page 0
happened to be mapped.
to be mapped.
Also:
* Push the wired page counting into the p->v list maintenance functions. This
avoids code duplication, and fixes some cases where we were confused about
which pages to do it with.
* Fix lots of problems associated with pmap_nightmare() (and rename it to
pmap_vac_me_harder()).
* Since the early pages are no longer considered `managed', just make
pmap_*_pv() panic if !pmap_initialized.
"BUS_SPACE_ALIGNED_POINTER()".
Equal to the param.h "ALIGNED_POINTER()" normally, but obeys additional
requirements of the bus_space_xxx_n() macros. (BUS_SPACE_DEBUG)
PTEs is ignored when in kernel mode. Hack around this just like we do on the
i386, by adding a prepass to copyout() to check for write permission on the
destination pages.
* Don't bother pulling PT_M and PT_H bits from pv_flags; they can't ever be
set there!
* Actually make pmap_clear_reference() do something useful.
* Also set the referenced bit (PT_H) when emulating a write fault.
If we're doing modified bit emulation, we must revoke write permission in
pmap_clear_modify(). This is non-negotiable. I will revoke write permission
in pmap_clear_modify(), or suffer the wrath of a thousand bricks.
mrg