- Copy stable/10 (r259064) to releng/10.0 as part of the
10.0-RELEASE cycle.
- Update __FreeBSD_version [1]
- Set branch name to -RC1

[1] 10.0-CURRENT __FreeBSD_version value ended at '55', so
start releng/10.0 at '100' so the branch is started with
a value ending in zero.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

The pmap function pmap_clear_reference() is no longer used. Remove it.

pmap_clear_reference() has had exactly one caller in the kernel for
several years, more precisely, since FreeBSD 8. Now, that call no
longer exists.

Approved by: re (kib)
Sponsored by: EMC / Isilon Storage Division

Revert r254501. Instead, reuse the type stability of the struct pmap
which is the part of struct vmspace, allocated from UMA_ZONE_NOFREE
zone. Initialize the pmap lock in the vmspace zone init function, and
remove pmap lock initialization and destruction from pmap_pinit() and
pmap_release().

Suggested and reviewed by: alc (previous version)
Tested by: pho
Sponsored by: The FreeBSD Foundation

The soft and hard busy mechanism rely on the vm object lock to work.
Unify the 2 concept into a real, minimal, sxlock where the shared
acquisition represent the soft busy and the exclusive acquisition
represent the hard busy.
The old VPO_WANTED mechanism becames the hard-path for this new lock
and it becomes per-page rather than per-object.
The vm_object lock becames an interlock for this functionality:
it can be held in both read or write mode.
However, if the vm_object lock is held in read mode while acquiring
or releasing the busy state, the thread owner cannot make any
assumption on the busy state unless it is also busying it.

Also:
- Add a new flag to directly shared busy pages while vm_page_alloc
and vm_page_grab are being executed. This will be very helpful
once these functions happen under a read object lock.
- Move the swapping sleep into its own per-object flag

The KPI is heavilly changed this is why the version is bumped.
It is very likely that some VM ports users will need to change
their own code.

Sponsored by: EMC / Isilon storage division
Discussed with: alc
Reviewed by: jeff, kib
Tested by: gavin, bapt (older version)
Tested by: pho, scottl

Replace kernel virtual address space allocation with vmem. This provides
transparent layering and better fragmentation.

- Normalize functions that allocate memory to use kmem_*
- Those that allocate address space are named kva_*
- Those that operate on maps are named kmap_*
- Implement recursive allocation handling for kmem_arena in vmem.

Reviewed by: alc
Tested by: pho
Sponsored by: EMC / Isilon Storage Division

Remove an unnecessary panic. The PVO's PTE entry and the PTEG's PTE entry may
not match, if the PVO's PTE is invalid.

Evict pages from the PTEG when it's full and trying to insert a new PTE,
rather than panicking.

Reviewed by: nwhitehorn
MFC after: 3 weeks

o Relax locking assertions for vm_page_find_least()
o Relax locking assertions for pmap_enter_object() and add them also
to architectures that currently don't have any
o Introduce VM_OBJECT_LOCK_DOWNGRADE() which is basically a downgrade
operation on the per-object rwlock
o Use all the mechanisms above to make vm_map_pmap_enter() to work
mostl of the times only with readlocks.

Sponsored by: EMC / Isilon storage division
Reviewed by: alc

Relax the object locking assertion in pmap_enter_locked().

Reviewed by: attilio
Sponsored by: EMC / Isilon Storage Division

Remove a comment that shouldn't have gone in.

X-MFC-with: r249864

Introduce kernel coredumps to ppc32 AIM. Leeched from the booke code.

MFC after: 2 weeks

Add pmap function pmap_copy_pages(), which copies the content of the
pages around, taking array of vm_page_t both for source and
destination. Starting offsets and total transfer size are specified.

The function implements optimal algorithm for copying using the
platform-specific optimizations. For instance, on the architectures
were the direct map is available, no transient mappings are created,
for i386 the per-cpu ephemeral page frame is used. The code was
typically borrowed from the pmap_copy_page() for the same
architecture.

Only i386/amd64, powerpc aim and arm/arm-v6 implementations were
tested at the time of commit. High-level code, not committed yet to
the tree, ensures that the use of the function is only allowed after
explicit enablement.

For sparc64, the existing code has known issues and a stab is added
instead, to allow the kernel linking.

Sponsored by: The FreeBSD Foundation
Tested by: pho (i386, amd64), scottl (amd64), ian (arm and arm-v6)
MFC after: 2 weeks

Switch the vm_object mutex to be a rwlock. This will enable in the
future further optimizations where the vm_object lock will be held
in read mode most of the time the page cache resident pool of pages
are accessed for reading purposes.

The change is mostly mechanical but few notes are reported:
* The KPI changes as follow:
- VM_OBJECT_LOCK() -> VM_OBJECT_WLOCK()
- VM_OBJECT_TRYLOCK() -> VM_OBJECT_TRYWLOCK()
- VM_OBJECT_UNLOCK() -> VM_OBJECT_WUNLOCK()
- VM_OBJECT_LOCK_ASSERT(MA_OWNED) -> VM_OBJECT_ASSERT_WLOCKED()
(in order to avoid visibility of implementation details)
- The read-mode operations are added:
VM_OBJECT_RLOCK(), VM_OBJECT_TRYRLOCK(), VM_OBJECT_RUNLOCK(),
VM_OBJECT_ASSERT_RLOCKED(), VM_OBJECT_ASSERT_LOCKED()
* The vm/vm_pager.h namespace pollution avoidance (forcing requiring
sys/mutex.h in consumers directly to cater its inlining functions
using VM_OBJECT_LOCK()) imposes that all the vm/vm_pager.h
consumers now must include also sys/rwlock.h.
* zfs requires a quite convoluted fix to include FreeBSD rwlocks into
the compat layer because the name clash between FreeBSD and solaris
versions must be avoided.
At this purpose zfs redefines the vm_object locking functions
directly, isolating the FreeBSD components in specific compat stubs.

The KPI results heavilly broken by this commit. Thirdy part ports must
be updated accordingly (I can think off-hand of VirtualBox, for example).

Sponsored by: EMC / Isilon storage division
Reviewed by: jeff
Reviewed by: pjd (ZFS specific review)
Discussed with: alc
Tested by: pho

Merge from vmobj-rwlock:
VM_OBJECT_LOCKED() macro is only used to implement a custom version
of lock assertions right now (which likely spread out thanks to
copy and paste).
Remove it and implement actual assertions.

Sponsored by: EMC / Isilon storage division
Reviewed by: alc
Tested by: pho

Merge from vmobj-rwlock branch:
Remove unused inclusion of vm/vm_pager.h and vm/vnode_pager.h.

Sponsored by: EMC / Isilon storage division
Tested by: pho
Reviewed by: alc

Setup BAT0 and BAT1 on the Wii.

This is the missing piece for FreeBSD/Wii, but there's still a lot of
work ahead. We have to reset the MMU in locore before continuing
the boot process because we don't know how the boot loaders might
have setup the BATs. We also disable the PCI BAT because there's no PCI
bus on the Wii.

Thanks to Nathan Whitehorn and Peter Grenhan for their help.

Submitted by: Margarida Gouveia

Rework the known rwlock to benefit about staying on their own
cache line in order to avoid manual frobbing but using
struct rwlock_padalign.

Reviewed by: alc, jimharris

Eliminate a stale comment. It describes another use case for the pmap in
Mach that doesn't exist in FreeBSD.

Avoid recursion on the pvh global lock in the aim oea pmap.

Correct the return type of the pmap_ts_referenced() implementations.

Reported by: jhibbits [1]
Tested by: andreast

Replace all uses of the vm page queues lock by a r/w lock that is private
to this pmap.

Tested by: andreast, jhibbits

Fix physical address type to vm_paddr_t.

Replace the list of PVOs owned by each PMAP with an RB tree. This simplifies
range operations like pmap_remove() and pmap_protect() as well as allowing
simple operations like pmap_extract() not to involve any global state.
This substantially reduces lock coverages for the global table lock and
improves concurrency.

We don't need kcopy() in any of the remaining places it is used, so
remove it.

MFC after: 2 weeks

Fix error in r233949. Synchronizing icaches on uncacheable pages turns out
not to be a good idea, and of course the PV entry list for a page is never
empty after the page has been mapped.

Reduce the frequency that the PowerPC/AIM pmaps invalidate instruction
caches, by invalidating kernel icaches only when needed and not flushing
user caches for shared pages.

Suggested by: kib
MFC after: 2 weeks

Use LIST_FOREACH_SAFE() instead of LIST_FOREACH() in pmap_remove(), since
the point of this loop is to remove elements. This worked by accident before.

MFC after: 2 days

Allow this to work on embedded systems without Open Firmware by making
lack of a /chosen non-fatal, and manually removing memory in use by the
kernel from the physical memory map.

Submitted by: rpaulo

Keep track of PVO entries in each pmap, which allows much faster
pmap_remove() for large sparse requests. This can prevent pmap_remove()
operations on 64-bit process destruction or swapout that would take
several hundred times the lifetime of the universe to complete. This
behavior is largely indistinguishable from a hang.

Add an extra invariant here which was useful on 64-bit CPUs.

Split the vm_page flags PG_WRITEABLE and PG_REFERENCED into atomic
flags field. Updates to the atomic flags are performed using the atomic
ops on the containing word, do not require any vm lock to be held, and
are non-blocking. The vm_page_aflag_set(9) and vm_page_aflag_clear(9)
functions are provided to modify afalgs.

Document the changes to flags field to only require the page lock.

Introduce vm_page_reference(9) function to provide a stable KPI and
KBI for filesystems like tmpfs and zfs which need to mark a page as
referenced.

Reviewed by: alc, attilio
Tested by: marius, flo (sparc64); andreast (powerpc, powerpc64)
Approved by: re (bz)

- Move the PG_UNMANAGED flag from m->flags to m->oflags, renaming the flag
to VPO_UNMANAGED (and also making the flag protected by the vm object
lock, instead of vm page queue lock).
- Mark the fake pages with both PG_FICTITIOUS (as it is now) and
VPO_UNMANAGED. As a consequence, pmap code now can use use just
VPO_UNMANAGED to decide whether the page is unmanaged.

Reviewed by: alc
Tested by: pho (x86, previous version), marius (sparc64),
marcel (arm, ia64, powerpc), ray (mips)
Sponsored by: The FreeBSD Foundation
Approved by: re (bz)

With retirement of cpumask_t and usage of cpuset_t for representing a
mask of CPUs, pc_other_cpus and pc_cpumask become highly inefficient.

Remove them and replace their usage with custom pc_cpuid magic (as,
atm, pc_cpumask can be easilly represented by (1 << pc_cpuid) and
pc_other_cpus by (all_cpus & ~(1 << pc_cpuid))).

This change is not targeted for MFC because of struct pcpu members
removal and dependency by cpumask_t retirement.

MD review by: marcel, marius, alc
Tested by: pluknet
MD testing by: marcel, marius, gonzo, andreast

etire the cpumask_t type and replace it with cpuset_t usage.

This is intended to fix the bug where cpu mask objects are
capped to 32. MAXCPU, then, can now arbitrarely bumped to whatever
value. Anyway, as long as several structures in the kernel are
statically allocated and sized as MAXCPU, it is suggested to keep it
as low as possible for the time being.

Technical notes on this commit itself:
- More functions to handle with cpuset_t objects are introduced.
The most notable are cpusetobj_ffs() (which calculates a ffs(3)
for a cpuset_t object), cpusetobj_strprint() (which prepares a string
representing a cpuset_t object) and cpusetobj_strscan() (which
creates a valid cpuset_t starting from a string representation).
- pc_cpumask and pc_other_cpus are target to be removed soon.
With the moving from cpumask_t to cpuset_t they are now inefficient
and not really useful. Anyway, for the time being, please note that
access to pcpu datas is protected by sched_pin() in order to avoid
migrating the CPU while reading more than one (possible) word
- Please note that size of cpuset_t objects may differ between kernel
and userland. While this is not directly related to the patch itself,
it is good to understand that concept and possibly use the patch
as a reference on how to deal with cpuset_t objects in userland, when
accessing kernland members.
- KTR_CPUMASK is changed and now is represented through a string, to be
set as the example reported in NOTES.

Please additively note that no MAXCPU is bumped in this patch, but
private testing has been done until to MAXCPU=128 on a real 8x8x2(htt)
machine (amd64).

Please note that the FreeBSD version is not yet bumped because of
the upcoming pcpu changes. However, note that this patch is not
targeted for MFC.

People to thank for the time spent on this patch:
- sbruno, pluknet and Nicholas Esborn (nick AT desert DOT net) tested
several revision of the patches and really helped in improving
stability of this work.
- marius fixed several bugs in the sparc64 implementation and reviewed
patches related to ktr.
- jeff and jhb discussed the basic approach followed.
- kib and marcel made targeted review on some specific part of the
patch.
- marius, art, nwhitehorn and andreast reviewed MD specific part of
the patch.
- marius, andreast, gonzo, nwhitehorn and jceel tested MD specific
implementations of the patch.
- Other people have made contributions on other patches that have been
already committed and have been listed separately.

Companies that should be mentioned for having participated at several
degrees:
- Yahoo! for having offered the machines used for testing on big
count of CPUs.
- The FreeBSD Foundation for having sponsored my devsummit attendance,
which has been instrumental.
- Sandvine for having offered offices and infrastructure during
development.

(I really hope I didn't forget anyone, if it happened I apologize in
advance).

Remove some dead code: unnecessary isyncs and memory sorting, which are
handled in mtmsr() and mem_regions(), respectively.

The macro MOEA_PVO_CHECK is empty and not used. It is a left over from the
NetBSD import. Remove the definition and all its occurrences.

Approved by: nwhitehorn (mentor)

Make MSGBUF_SIZE kernel option a loader tunable kern.msgbufsize.

Submitted by: perryh pluto.rain.com (previous version)
Reviewed by: jhb
Approved by: kib (mentor)
Tested by: universe

Garbage-collect unused variable.

Add an abstraction layer to the 64-bit AIM MMU's page table manipulation
logic to support modifying the page table through a hypervisor. This
uses KOBJ inheritance to provide subclasses of the base 64-bit AIM MMU
class with additional methods for page table manipulation.

Many thanks to Peter Grehan for suggesting this design and implementing
the MMU KOBJ inheritance mechanism.

Remove use of a separate ofw_pmap on 32-bit CPUs. Many Open Firmware
mappings need to end up in the kernel anyway since the kernel begins
executing in OF context. Separating them adds needless complexity,
especially since the powerpc64 and mmu_oea64 code gave up on it a long
time ago.

As a side effect, the PPC ofw_machdep code is no longer AIM-specific,
so move it to powerpc/ofw.

Implement pmap_is_prefaultable().

Reviewed by: nwhitehorn

Add some missing parentheses so that moea_bat_mapped() actually works.

Submitted by: alc
MFC after: 3 days

Follow exactly the steps in architecture manual for correctly invalidating
TLB entries instead of trying to cut corners.

Fix pmap_page_set_memattr() behavior in the presence of fictitious pages
by just caching the mode for later use by pmap_enter(), following amd64.
While here, correct some mismerges from mmu_oea64 -> mmu_oea and clean
up some dead code found while fixing the fictitious page behavior.

Add support for memory attributes (pmap_mapdev_attr() and friends) on
PowerPC/AIM. This is currently stubbed out on Book-E, since I have no
idea how to implement it there.

Introduce inheritance into the PowerPC MMU kobj interface.

include/mmuvar.h - Change the MMU_DEF macro to also create the class
definition as well as define the DATA_SET. Add a macro, MMU_DEF_INHERIT,
which has an extra parameter specifying the MMU class to inherit methods
from. Update the comments at the start of the header file to describe the
new macros.

booke/pmap.c
aim/mmu_oea.c
aim/mmu_oea64.c - Collapse mmu_def_t declaration into updated MMU_DEF macro

The MMU_DEF_INHERIT macro will be used in the PS3 MMU implementation to
allow it to inherit the stock powerpc64 MMU methods.

Reviewed by: nwhitehorn

Fix a typo in the original import of this code from NetBSD that caused the
wrong element of the VSID bitmap array to be examined after a collision,
leading to reallocation of in-use VSIDs under some circumstances, with
attendant memory corruption. Also add an assert to check for this kind of
problem in the future.

MFC after: 4 days

Fix the same race condition on 32-bit AIM CPUs that was fixed for 64-bit
ones in r211967 involving VSID allocation.

pmap_mapdev() does not appear to actually need GIANT to be held here,
and asserting that is held breaks drm.

MFC after: 2 weeks

MFppc64:

Kernel sources for 64-bit PowerPC, along with build-system changes to keep
32-bit kernels compiling (build system changes for 64-bit kernels are
coming later). Existing 32-bit PowerPC kernel configurations must be
updated after this change to specify their architecture.

Temporarily disable instruction relocation while setting up the kernel's
IBAT entry in early boot in order to prevent possible faults from races
between the instruction cache and the MMU.

PR: powerpc/148003
MFC after: 3 days

Relax one of the new assertions in pmap_enter() a little. Specifically,
allow pmap_enter() to be performed on an unmanaged page that doesn't have
VPO_BUSY set. Having VPO_BUSY set really only matters for managed pages.
(See, for example, pmap_remove_write().)

Reduce the scope of the page queues lock and the number of
PG_REFERENCED changes in vm_pageout_object_deactivate_pages().
Simplify this function's inner loop using TAILQ_FOREACH(), and shorten
some of its overly long lines. Update a stale comment.

Assert that PG_REFERENCED may be cleared only if the object containing
the page is locked. Add a comment documenting this.

Assert that a caller to vm_page_requeue() holds the page queues lock,
and assert that the page is on a page queue.

Push down the page queues lock into pmap_ts_referenced() and
pmap_page_exists_quick(). (As of now, there are no longer any pmap
functions that expect to be called with the page queues lock held.)

Neither pmap_ts_referenced() nor pmap_page_exists_quick() should ever
be passed an unmanaged page. Assert this rather than returning "0"
and "FALSE" respectively.

ARM:

Simplify pmap_page_exists_quick() by switching to TAILQ_FOREACH().

Push down the page queues lock inside of pmap_clearbit(), simplifying
pmap_clear_modify(), pmap_clear_reference(), and pmap_remove_write().
Additionally, this allows for avoiding the acquisition of the page
queues lock in some cases.

PowerPC/AIM:

moea*_page_exits_quick() and moea*_page_wired_mappings() will never be
called before pmap initialization is complete. Therefore, the check
for moea_initialized can be eliminated.

Push down the page queues lock inside of moea*_clear_bit(),
simplifying moea*_clear_modify() and moea*_clear_reference().

The last parameter to moea*_clear_bit() is never used. Eliminate it.

PowerPC/BookE:

Simplify mmu_booke_page_exists_quick()'s control flow.

Reviewed by: kib@

Correct a harmless typo introduced when copying code from mmu_oea64.

Submitted by: alc
MFC after: 8.1-RELEASE

Don't set PG_WRITEABLE in pmap_enter() unless the page is managed.

Push down page queues lock acquisition in pmap_enter_object() and
pmap_is_referenced(). Eliminate the corresponding page queues lock
acquisitions from vm_map_pmap_enter() and mincore(), respectively. In
mincore(), this allows some additional cases to complete without ever
acquiring the page queues lock.

Assert that the page is managed in pmap_is_referenced().

On powerpc/aim, push down the page queues lock acquisition from
moea*_is_modified() and moea*_is_referenced() into moea*_query_bit().
Again, this will allow some additional cases to complete without ever
acquiring the page queues lock.

Reorder a few statements in vm_page_dontneed() so that a race can't lead
to an old reference persisting. This scenario is described in detail by a
comment.

Correct a spelling error in vm_page_dontneed().

Assert that the object is locked in vm_page_clear_dirty(), and restrict the
page queues lock assertion to just those cases in which the page is
currently writeable.

Add object locking to vnode_pager_generic_putpages(). This was the one
and only place where vm_page_clear_dirty() was being called without the
object being locked.

Eliminate an unnecessary vm_page_lock() around vnode_pager_setsize()'s call
to vm_page_clear_dirty().

Change vnode_pager_generic_putpages() to the modern-style of function
definition. Also, change the name of one of the parameters to follow
virtual memory system naming conventions.

Reviewed by: kib

Roughly half of a typical pmap_mincore() implementation is machine-
independent code. Move this code into mincore(), and eliminate the
page queues lock from pmap_mincore().

Push down the page queues lock into pmap_clear_modify(),
pmap_clear_reference(), and pmap_is_modified(). Assert that these
functions are never passed an unmanaged page.

Eliminate an inaccurate comment from powerpc/powerpc/mmu_if.m:
Contrary to what the comment says, pmap_mincore() is not simply an
optimization. Without a complete pmap_mincore() implementation,
mincore() cannot return either MINCORE_MODIFIED or MINCORE_REFERENCED
because only the pmap can provide this information.

Eliminate the page queues lock from vfs_setdirty_locked_object(),
vm_pageout_clean(), vm_object_page_collect_flush(), and
vm_object_page_clean(). Generally speaking, these are all accesses
to the page's dirty field, which are synchronized by the containing
vm object's lock.

Reduce the scope of the page queues lock in vm_object_madvise() and
vm_page_dontneed().

Reviewed by: kib (an earlier version)

On entry to pmap_enter(), assert that the page is busy. While I'm
here, make the style of assertion used by pmap_enter() consistent
across all architectures.

On entry to pmap_remove_write(), assert that the page is neither
unmanaged nor fictitious, since we cannot remove write access to
either kind of page.

With the push down of the page queues lock, pmap_remove_write() cannot
condition its behavior on the state of the PG_WRITEABLE flag if the
page is busy. Assert that the object containing the page is locked.
This allows us to know that the page will neither become busy nor will
PG_WRITEABLE be set on it while pmap_remove_write() is running.

Correct a long-standing bug in vm_page_cowsetup(). We cannot possibly
do copy-on-write-based zero-copy transmit on unmanaged or fictitious
pages, so don't even try. Previously, the call to pmap_remove_write()
would have failed silently.

Push down the page queues into vm_page_cache(), vm_page_try_to_cache(), and
vm_page_try_to_free(). Consequently, push down the page queues lock into
pmap_enter_quick(), pmap_page_wired_mapped(), pmap_remove_all(), and
pmap_remove_write().

Push down the page queues lock into Xen's pmap_page_is_mapped(). (I
overlooked the Xen pmap in r207702.)

Switch to a per-processor counter for the total number of pages cached.

On Alan's advice, rather than do a wholesale conversion on a single
architecture from page queue lock to a hashed array of page locks
(based on a patch by Jeff Roberson), I've implemented page lock
support in the MI code and have only moved vm_page's hold_count
out from under page queue mutex to page lock. This changes
pmap_extract_and_hold on all pmaps.

Supported by: Bitgravity Inc.

Discussed with: alc, jeffr, and kib

Resurrect pmap_is_referenced() and use it in mincore(). Essentially,
pmap_ts_referenced() is not always appropriate for checking whether or
not pages have been referenced because it clears any reference bits
that it encounters. For example, in mincore(), clearing the reference
bits has two negative consequences. First, it throws off the activity
count calculations performed by the page daemon. Specifically, a page
on which mincore() has called pmap_ts_referenced() looks less active
to the page daemon than it should. Consequently, the page could be
deactivated prematurely by the page daemon. Arguably, this problem
could be fixed by having mincore() duplicate the activity count
calculation on the page. However, there is a second problem for which
that is not a solution. In order to clear a reference on a 4KB page,
it may be necessary to demote a 2/4MB page mapping. Thus, a mincore()
by one process can have the side effect of demoting a superpage
mapping within another process!

Reduce KVA pressure on OEA64 systems running in bridge mode by mapping
UMA segments at their physical addresses instead of into KVA. This emulates
the direct mapping behavior of OEA32 in an ad-hoc way. To make this work
properly required sharing the entire kernel PMAP with Open Firmware, so
ofw_pmap is transformed into a stub on 64-bit CPUs.

Also implement some more tweaks to get more mileage out of our limited
amount of KVA, principally by extending KVA into segment 16 until the
beginning of the first OFW mapping.

Reported by: linimon

Fix a bug where pages being removed from memory entirely no longer have
PVOs, and so the modified state of the page can no longer be communicated
to the VM layer, causing pages not to be flushed to swap when needed, in
turn causing memory corruption. Also make several correctness adjustments
to I-Cache synchronization and TLB invalidation for 64-bit Book-S CPUs.

Obtained from: projects/ppc64
Discussed with: grehan
MFC after: 2 weeks

Remove extraneous semicolons, no functional changes.

Submitted by: Marc Balmer <marc@msys.ch>
MFC after: 1 week

o Introduce vm_sync_icache() for making the I-cache coherent with
the memory or D-cache, depending on the semantics of the platform.
vm_sync_icache() is basically a wrapper around pmap_sync_icache(),
that translates the vm_map_t argumument to pmap_t.
o Introduce pmap_sync_icache() to all PMAP implementation. For powerpc
it replaces the pmap_page_executable() function, added to solve
the I-cache problem in uiomove_fromphys().
o In proc_rwmem() call vm_sync_icache() when writing to a page that
has execute permissions. This assures that when breakpoints are
written, the I-cache will be coherent and the process will actually
hit the breakpoint.
o This also fixes the Book-E PMAP implementation that was missing
necessary locking while trying to deal with the I-cache coherency
in pmap_enter() (read: mmu_booke_enter_locked).

The key property of this change is that the I-cache is made coherent
*after* writes have been done. Doing it in the PMAP layer when adding
or changing a mapping means that the I-cache is made coherent *before*
any writes happen. The difference is key when the I-cache prefetches.

Implement a facility for dynamic per-cpu variables.
- Modules and kernel code alike may use DPCPU_DEFINE(),
DPCPU_GET(), DPCPU_SET(), etc. akin to the statically defined
PCPU_*. Requires only one extra instruction more than PCPU_* and is
virtually the same as __thread for builtin and much faster for shared
objects. DPCPU variables can be initialized when defined.
- Modules are supported by relocating the module's per-cpu linker set
over space reserved in the kernel. Modules may fail to load if there
is insufficient space available.
- Track space available for modules with a one-off extent allocator.
Free may block for memory to allocate space for an extent.

Reviewed by: jhb, rwatson, kan, sam, grehan, marius, marcel, stas

Factor out platform dependent things unrelated to device drivers into a
new platform module. These are probed in early boot, and have the
responsibility of determining the layout of physical memory, determining
the CPU timebase frequency, and handling the zoo of SMP mechanisms
found on PowerPC.

Reviewed by: marcel, raj
Book-E parts by: raj

Add support for 64-bit PowerPC CPUs operating in the 64-bit bridge mode
provided, for example, on the PowerPC 970 (G5), as well as on related CPUs
like the POWER3 and POWER4.

This also adds support for various built-in hardware found on Apple G5
hardware (e.g. the IBM CPC925 northbridge).

Reviewed by: grehan

Change the PVO zone for fictitious pages to the unmanaged PVO zone, to match
the unmanaged flag set in the PVO attributes. Without doing this,
pmap_remove() could try to remove fictitious pages (like those created
by mmap of physical memory) from the wrong UMA zone, causing a panic.

Reported by: Justin Hibbits
MFC after: 1 week

In preparation for PowerPC G5 support, allow PVO objects to contain page
table entries for both the 32-bit and 64-bit AIM MMUs.

o When not making a translation cache-inhibit and guarded (PTE_I|PTE_G)
make it memory-coherency enforced (PTE_M). This is required for SMP
to work.
o Serialize tlbie operations and implement the tlbie operation in a
function called tlbie(). Hardware can end up in a live-lock if
between the tlbsync and subsequent sync on one processor another
processor executes a tlbie or tlbsync.
o Eliminate the following defines:
TLBIE, TLBSYNC, SYNC and EIEIO
Use either inline assembly statements or inline functions defined
in <machine/cpufunc.h>

Remove the tracing from the AP startup. The AP is known
to start and the tracing can interfere with AP startup.
Instead, use the available space in the reset vector
for the initial stack.

Remove redundant KTR statements.

Invalidate the TLB in pmap_cpu_bootstrap(), so that it also happens
on the APs.

The first argment of mtdbatu or mtibatu is part of the encoding.
It needs to be constant, so eliminate the loop and "hand-unroll".

MFp4: SMP support

Simplify the pmap_zero_page family of functions by making use of
the fact that we have a 1:1 mapping by virtue of the BATs.
Eliminate the now unused moea_rkva_alloc(), moea_pa_map() and
moea_pa_unmap() functions.

Pointed out by: grehan.

Allocate a stack (with optional guard pages) for thread0 and
switch to it before calling mi_startup().

Forced commit to record that this file was repocopied from
src/sys/powerpc/powerpc and modified for its new location.

Prevent the leakage of wired pages in the following circumstances:
First, a file is mmap(2)ed and then mlock(2)ed. Later, it is truncated.
Under "normal" circumstances, i.e., when the file is not mlock(2)ed, the
pages beyond the EOF are unmapped and freed. However, when the file is
mlock(2)ed, the pages beyond the EOF are unmapped but not freed because
they have a non-zero wire count. This can be a mistake. Specifically,
it is a mistake if the sole reason why the pages are wired is because of
wired, managed mappings. Previously, unmapping the pages destroys these
wired, managed mappings, but does not reduce the pages' wire count.
Consequently, when the file is unmapped, the pages are not unwired
because the wired mapping has been destroyed. Moreover, when the vm
object is finally destroyed, the pages are leaked because they are still
wired. The fix is to reduce the pages' wired count by the number of
wired, managed mappings destroyed. To do this, I introduce a new pmap
function pmap_page_wired_mappings() that returns the number of managed
mappings to the given physical page that are wired, and I use this
function in vm_object_page_remove().

Reviewed by: tegge
MFC after: 6 weeks

Remove bogus increment of re-hashed PTEG index. This snuck in with r1.12 of
pmap.c, and is potentially the cause of hangs reported on machines with a
small amount of memory. On machines with sufficient RAM, and without a lot
of processes running, this situation would probably never occur.

Testing is still incomplete, but it is obviously wrong so remove the
offending code now.

The issue of what to do when both the primary and secondary hash overflow
is still open.

Reported by: Dan Kresja at windriver dot com, via alc

Fix gdb issue where the i-cache was not being updated when a breakpoint
was written into a user's address space. The fix is to modify uiomove_fromphys
to sync the icache when an executable user-space page is written into.

Alan Cox suggested that there should probably be a higher-level interface
to this in the ptrace code, but agreed that this is an OK short-term solution.

Files changed:

pmap.h - declaration of pmap_page_executable()
pmap_dispatch.c - pass through the page_executable call to the mmu object
mmu_oea.c - implement the page_executable method by examining the PTE_EXEC
field in the vm_page_t
uio_machdep.c - in uiomove_fromphys(), if the op was a UIO_WRITE to user-space,
and if the page is executable, sync the icache since this is at the least
a breakpoint-write from gdb.

Reported by: marcel
Tested by: marcel, grehan on g3+g4
Discussed with: alc
MFC after: 2 weeks

Don't use vm_page_flag_set() if installing bootstrap page-table entries
since the vm page mutex's aren't yet initialized. Fixes boot-time panic.

Reported by: Dario Freni saturnero at freesbie dot org

Make pmap_enter() responsible for setting PG_WRITEABLE instead
of its caller. (As a beneficial side-effect, a high-contention
acquisition of the page queues lock in vm_fault() is eliminated.)

Complete the transition from pmap_page_protect() to pmap_remove_write().
Originally, I had adopted sparc64's name, pmap_clear_write(), for the
function that is now pmap_remove_write(). However, this function is more
like pmap_remove_all() than like pmap_clear_modify() or
pmap_clear_reference(), hence, the name change.

The higher-level rationale behind this change is described in
src/sys/amd64/amd64/pmap.c revision 1.567. The short version is that I'm
trying to clean up and fix our support for execute access.

Reviewed by: marcel@ (ia64)

Add synchronization to moea_zero_page() and moea_zero_page_area().

Remove the acquisition and release of Giant from moea_zero_page_idle().

Tested by: grehan@

Eliminate the acquisition and release of Giant from moea_extract_and_hold()
and moea_protect().

Tested by: grehan@ and rink@

Synchronize accesses to the PTEG table.

Add many lock assertions.

Tested by: grehan@

Prevent 'mutex not owned' panic on boot if INVARIANTS is in the kernel. This
makes the GENERIC kernel boot on ppc.

Reviewed by: grehan
Approved by: imp (mentor)
MFC after: 1 week

dCVS: ----------------------------------------------------------------------

Remove mpte optimization from pmap_enter_quick().
There is a race with the current locking scheme and removing
it should have no measurable performance impact.
This fixes page faults leading to panics in pmap_enter_quick_locked()
on amd64/i386.

Reviewed by: alc,jhb,peter,ps

Correct a typo in the previous revision.

Introduce the function pmap_enter_object(). It maps a sequence of resident
pages from the same object. Use it in vm_map_pmap_enter() to reduce the
locking overhead of premapping objects.

Reviewed by: tegge@

Name change from pmap_* to moea_* to fit into the new order of
mmu implementation.

This code handles the 32-bit 'OEA' MMU found on G2/G3/G4 PPC cores.

Forced commit to note that this file has been repo-copied
from pmap.c

Fix boot-time hang/panic on G3 systems when modifying IBAT0 in
pmap_bootstrap by using the sync;isync big hammer to make sure
all prior operations have completed.

Reported by: Nathan Whitehorn <nathan at uchicago edu>
MFC after: 2 days

Pass a value of type vm_prot_t to pmap_enter_quick() so that it determine
whether the mapping should permit execute access.

Introduce a procedure, pmap_page_init(), that initializes the
vm_page's machine-dependent fields. Use this function in
vm_pageq_add_new_page() so that the vm_page's machine-dependent and
machine-independent fields are initialized at the same time.

Remove code from pmap_init() for initializing the vm_page's
machine-dependent fields.

Remove stale comments from pmap_init().

Eliminate the Boolean variable pmap_initialized from the alpha, amd64,
i386, and ia64 pmap implementations. Its use is no longer required
because of the above changes and earlier changes that result in physical
memory that is being mapped at initialization time being mapped without
pv entries.

Tested by: cognet, kensmith, marcel

Replaced previous hw.physmem extraction with des's mods to
getenv_ulong() - much simpler.

Pointed out by: des

Allow user to undersize memory with hw.physmem loader variable.

Obtained from: i386/machdep.c:getmemsize()

Add PVO_FAKE flag to pvo entries for PG_FICTITIOUS mappings, to
avoid trying to reverse-map a device physical address to the
vm_page array and walking into non-existent vm weeds.

found by: Xorg server exiting

Fix (accidental?) lock order reversal in pmap_remove. Found when
a process that has mmap'd device mem exits.

/* -> /*- for license, minor formatting changes

Correctly initialise the 2nd kernel segment, and don't
forget to actually install it in the segment register.
This may fix some of the weird panics seen when kernel VM
is heavily used.

Modify pmap_enter_quick() so that it expects the page queues to be locked
on entry and it assumes the responsibility for releasing the page queues
lock if it must sleep.

Remove a bogus comment from pmap_enter_quick().

Using the first change, modify vm_map_pmap_enter() so that the page queues
lock is acquired and released once, rather than each time that a page
is mapped.

In the common case, pmap_enter_quick() completes without sleeping.
In such cases, the busying of the page and the unlocking of the
containing object by vm_map_pmap_enter() and vm_fault_prefault() is
unnecessary overhead. To eliminate this overhead, this change
modifies pmap_enter_quick() so that it expects the object to be locked
on entry and it assumes the responsibility for busying the page and
unlocking the object if it must sleep. Note: alpha, amd64, i386 and
ia64 are the only implementations optimized by this change; arm,
powerpc, and sparc64 still conservatively busy the page and unlock the
object within every pmap_enter_quick() call.

Additionally, this change is the first case where we synchronize
access to the page's PG_BUSY flag and busy field using the containing
object's lock rather than the global page queues lock. (Modifications
to the page's PG_BUSY flag and busy field have asserted both locks for
several weeks, enabling an incremental transition.)

Lock the kernel pmap in pmap_kenter().

Tested by: gallatin@

- Introduce a lock for synchronizing access to the pvo and pteg tables.
- In pmap_enter(), only the acquisition and release of the page queues
lock needs to check the bootstrap flag.

Tested by: gallatin@

Eliminate unnecessary indirection.

Add pmap locking to many of the functions.

Many thanks to Andrew Gallatin for resolving a powerpc-specific
initialization problem in my original patch.

Tested by: gallatin@

Instead of "OpenFirmware", "openfirmware", etc. use the official spelling
"Open Firmware" from IEEE 1275 and OpenFirmware.org (no pun intended).

Ok'ed by: tmm

Add /dev/mem and /dev/kmem to powerpc.

Approved by: grehan (mentor)

In pmap_page_protect, clear the vm page's PG_WRITEABLE flag if
downgrading to read-only. Found by triggering the KASSERT in
vm_pageout_flush().

- Push down the acquisition and release of Giant into pmap_enter_quick()
on those architectures without pmap locking.
- Eliminate the acquisition and release of Giant in vm_map_pmap_enter().

- Push down the acquisition and release of Giant into pmap_protect() on
those architectures without pmap locking.
- Eliminate the acquisition and release of Giant from vm_map_protect().

(Translation: mprotect(2) runs to completion without touching Giant on
alpha, amd64, i386 and ia64.)

Implement the protection check required by the pmap_extract_and_hold()
specification.

Reviewed and tested by: grehan@

Push down the acquisition and release of the page queues lock into
pmap_protect() and pmap_remove(). In general, they require the lock in
order to modify a page's pv list or flags. In some cases, however,
pmap_protect() can avoid acquiring the lock.

pmap_remove_pages() must not remove wired mappings. Since
pmap_remove_pages() is an optimization, its implementation is optional.

Discussed with: grehan

G4 requires isync after 256Mb ibat/dbat update, G3 requires
isync after each bat update. Otherwise, pmap_bootstrap causes
an ISI exception. A fall-out of loader BAT removal.

Correct pmap_extract()'s return type. It should be vm_paddr_t, not
vm_offset_t.

Modify loop test when cycling through phys_avail array. It's possible
for an OpenFirmware implementation to have a single memory region
(hello PearPC).

Remove avail_end. It is not used.

Remove avail_start on those platforms that no longer use it. (Only amd64
does anything with it beyond simple initialization.)

Remove unused arguments from pmap_init().

Retire pmap_pinit2(). Alpha was the last platform that used it. However,
ever since alpha/alpha/pmap.c revision 1.81 introduced the list allpmaps,
there has been no reason for having this function on Alpha. Briefly,
when pmap_growkernel() relied upon the list of all processes to find and
update the various pmaps to reflect a growth in the kernel's valid
address space, pmap_init2() served to avoid a race between pmap
initialization and pmap_growkernel(). Specifically, pmap_pinit2() was
responsible for initializing the kernel portions of the pmap and
pmap_pinit2() was called after the process structure contained a pointer
to the new pmap for use by pmap_growkernel(). Thus, an update to the
kernel's address space might be applied to the new pmap unnecessarily,
but an update would never be lost.

Increase kernel VA from 256Mb to 512Mb by shifting the segment used
for user copyinout down to 12, and keeping segments 13/14 for
kernel VA.

It would be nice to have more available, but segments lower than
this are reserved for either memory or 1:1 mapped device i/o,
and seg 15 is OpenFirmware ROM. Also, the effort to keep OpenFirmware
available for callbacks limits the use of VA-mapped segments.
Fortunately UMA_MD_SMALL_ALLOC takes away a lot of VM pressure.

Obtained from: NetBSD

Cleaned up param.h:

- culled long-dead #define's
- segment register defs moved to sr.h
- NPMAPS moved to pmap.h
- KERNBASE moved to vmparam.h
- removed include of <machine/cpu.h> and fixed src files that
relied on this.

Modifying segment register code no longer causes gcc rebuilds :-)

Remove pmap_pvo_allocf zone alloc function. It was a way of
using the direct-mapping of physmem to force PTE data structures
to be physically addressable so the interrupt-time real-mode
DSI trap handler could perform PTE spills. However, the memory
may have been > 256Mb, which would have caused a BAT spill and
double-interrupt.

The new trap code no longer handles PTE spills, so the requirement
that these pages be direct-mapped no longer applies. The irony is
UMA_MD_SMALL_ALLOC will return direct mappings for these structs :-)

When UMA_MD_SMALL_ALLOC is defined, pmap_kextract will be called
for direct-mapped addresses. Assume that any address less than KVA
is one of these and return it. Also assert that an address is KVA
does have a valid mapping - callers of pmap_kextract don't check
the return value, since they assume that they have a valid virtual
address.

Disable the per-vm_page PTE cache. This was not being invalidated
correctly, resulting in the dreaded "vm_pageout_flush: partially
invalid page" panic. The caching issue will be revisited in the
future, but opt for safety over performance in the meantime.

Tested by: gallatin

pmap_query_bit() should return false if the bit is not set.

Reviewed by: grehan

Migrate pmap_prefault() into the machine-independent virtual memory layer.

A small helper function pmap_is_prefaultable() is added. This function
encapsulate the few lines of pmap_prefault() that actually vary from
machine to machine. Note: pmap_is_prefaultable() and pmap_mincore() have
much in common. Going forward, it's worth considering their merger.

Soften assert in pmap_remove_all.
Introduct pmap_extract_and_hold.

Stolen from: sparc64

Use kmem_alloc_nofault() rather than kmem_alloc_pageable() in pmap_mapdev().
See revision 1.140 of kern/sys_pipe.c for a detailed rationale.

Submitted by: tegge

Make sure that when the PV ENTRY zone is created in pmap, that it's
created not only with UMA_ZONE_VM but also with UMA_ZONE_NOFREE. In
the i386 case in particular, the pmap code would hook a special
page allocation routine that allocated from kernel_map and not kmem_map,
and so when/if the pageout daemon drained the zones, it could actually
push out slabs from the PV ENTRY zone but call UMA's default page_free,
which resulted in pages allocated from kernel_map being freed to
kmem_map; bad. kmem_free() ignores the return value of the
vm_map_delete and just returns. I'm not sure what the exact
repercussions could be, but it doesn't look good.

In the PAE case on i386, we also set-up a zone in pmap, so be
conservative for now and make that zone also ZONE_NOFREE and
ZONE_VM. Do this for the pmap zones for the other archs too,
although in some cases it may not be entirely necessarily. We'd
rather be safe than sorry at this point.

Perhaps all UMA_ZONE_VM zones should by default be also
UMA_ZONE_NOFREE?

May fix some of silby's crashes on the PV ENTRY zone.

Deal with 'options KSTACK_PAGES' being a global option.

Make pmap_pvo_allocf() callable without Giant.

Background: pmap_object_init_pt() premaps the pages of a object in
order to avoid the overhead of later page faults. In general, it
implements two cases: one for vnode-backed objects and one for
device-backed objects. Only the device-backed case is really
machine-dependent, belonging in the pmap.

This commit moves the vnode-backed case into the (relatively) new
function vm_map_pmap_enter(). On amd64 and i386, this commit only
amounts to code rearrangement. On alpha and ia64, the new machine
independent (MI) implementation of the vnode case is smaller and more
efficient than their pmap-based implementations. (The MI
implementation takes advantage of the fact that objects in -CURRENT
are ordered collections of pages.) On sparc64, pmap_object_init_pt()
hadn't (yet) been implemented.

- Export pmap_enter_quick() to the MI VM. This will permit the
implementation of a largely MI pmap_object_init_pt() for vnode-backed
objects. pmap_enter_quick() is implemented via pmap_enter() on sparc64
and powerpc.
- Correct a mismatch between pmap_object_init_pt()'s prototype and its
various implementations. (I plan to keep pmap_object_init_pt() as
the MD hook for device-backed objects on i386 and amd64.)
- Correct an error in ia64's pmap_enter_quick() and adjust its interface
to match the other versions. Discussed with: marcel

Migrate the thread stack management functions from the machine-dependent
to the machine-independent parts of the VM. At the same time, this
introduces vm object locking for the non-i386 platforms.

Two details:

1. KSTACK_GUARD has been removed in favor of KSTACK_GUARD_PAGES. The
different machine-dependent implementations used various combinations
of KSTACK_GUARD and KSTACK_GUARD_PAGES. To disable guard page, set
KSTACK_GUARD_PAGES to 0.

2. Remove the (unnecessary) clearing of PG_ZERO in vm_thread_new. In
5.x, (but not 4.x,) PG_ZERO can only be set if VM_ALLOC_ZERO is passed
to vm_page_alloc() or vm_page_grab().

Move the *_new_altkstack() and *_dispose_altkstack() functions out of the
various pmap implementations into the machine-independent vm. They were
all identical.

Use __FBSDID rather than rcsid[].

Cleanup of the d_mmap_t interface.

- Get rid of the useless atop() / pmap_phys_address() detour. The
device mmap handlers must now give back the physical address
without atop()'ing it.
- Don't borrow the physical address of the mapping in the returned
int. Now we properly pass a vm_offset_t * and expect it to be
filled by the mmap handler when the mapping was successful. The
mmap handler must now return 0 when successful, any other value
is considered as an error. Previously, returning -1 was the only
way to fail. This change thus accidentally fixes some devices
which were bogusly returning errno constants which would have been
considered as addresses by the device pager.
- Garbage collect the poorly named pmap_phys_address() now that it's
no longer used.
- Convert all the d_mmap_t consumers to the new API.

I'm still not sure wheter we need a __FreeBSD_version bump for this,
since and we didn't guarantee API/ABI stability until 5.1-RELEASE.

Discussed with: alc, phk, jake
Reviewed by: peter
Compile-tested on: LINT (i386), GENERIC (alpha and sparc64)
Runtime-tested on: i386

- add pmap_pagedaemon_waken variable
- remove dead code and fix warnings in pmap_zero_page/zero_page_area
- implement
pmap_clear_reference
pmap_ts_referenced
pmap_page_exists_quick
pmap_remove_all
- align pmap_qenter/qremove closer with i386 code
- fix vm_page locking in pmap_new_thread (from benno)
- add new parameter to pmap_clear_bit to return original
pte value

Approved by: benno

Back out some changes that snuck in with the last commit.

Pointy hat to: benno

Flesh out bus_dmamap_sync.

Move pmap_collect() out of the machine-dependent code, rename it
to reflect its new location, and add page queue and flag locking.

Notes: (1) alpha, i386, and ia64 had identical implementations
of pmap_collect() in terms of machine-independent interfaces;
(2) sparc64 doesn't require it; (3) powerpc had it as a TODO.

- fix zero-sized stack alloc from previous commit. a default is now
selected ala sparc64
- KSEIII routines implemented (taken from i386/sparc64)

Approved by: Benno

Some kernel threads try to do significant work, and the default KSTACK_PAGES
doesn't give them enough stack to do much before blowing away the pcb.
This adds MI and MD code to allow the allocation of an alternate kstack
who's size can be speficied when calling kthread_create. Passing the
value 0 prevents the alternate kstack from being created. Note that the
ia64 MD code is missing for now, and PowerPC was only partially written
due to the pmap.c being incomplete there.
Though this patch does not modify anything to make use of the alternate
kstack, acpi and usb are good candidates.

Reviewed by: jake, peter, jhb

- use BAT registers to map device space and physical memory
- remove test in pmap_activate that prevented vmspace sharing (v/rfork)
- always sync icache in pmap_enter until problems are sorted
- fix incorrect use of regions in pmap_kenter
- bring in pmap_release from NetBSD
- fix overwrite of bootstrap flag in pmap_pvo_enter

Approved by: benno

o Retire pmap_pageable(). It's an advisory routine that none
of our platforms implements.

o Don't set PG_MAPPED or PG_WRITEABLE when a page is mapped
using pmap_kenter() or pmap_qenter().
o Use VM_ALLOC_WIRED in pmap_new_thread().

Remove the statically allocated array that holds OpenFirmware memory mappings
during pmap_bootstrap. Instead, temporarily help ourselves to some memory
from phys_avail since we won't need it post-boostrap.

Add an implementation for pmap_zero_page_area.

Add a special page zero entry point intended to be called via the single
threaded VM pagezero kthread outside of Giant. For some platforms, this
is really easy since it can just use the direct mapped region. For others,
IPI sending is involved or there are other issues, so grab Giant when
needed.

We still have preemption issues to deal with, but Alan Cox has an
interesting suggestion on how to minimize the problem on x86.

Use Luigi's hack for preserving the (lack of) priority.

Turn the idle zeroing back on since it can now actually do something useful
outside of Giant in many cases.

Collect all the (now equivalent) pmap_new_proc/pmap_dispose_proc/
pmap_swapin_proc/pmap_swapout_proc functions from the MD pmap code
and use a single equivalent MI version. There are other cleanups
needed still.

While here, use the UMA zone hooks to keep a cache of preinitialized
proc structures handy, just like the thread system does. This eliminates
one dependency on 'struct proc' being persistent even after being freed.
There are some comments about things that can be factored out into
ctor/dtor functions if it is worth it. For now they are mostly just
doing statistics to get a feel of how it is working.

Update for post-kse3 pmap kthread allocation changes

Add pmap_mapdev and pmap_unmapdev.

- Initialise battable to cover I/O spaces.
- Statically size the bpvo entries to avoid conflicts between bpvo allocation
and the vm allocator.
- Shift pmap_init2 code into pmap_init.
- Add UMA_ZONE_VM flag to uma_zcreate.

Submitted by: Peter Grehan <peterg@ptree32.com.au>

Implement pmap_copy and pmap_copy_page.

Get the correct memory regions from OpenFirmware. We were getting the
"available" ranges, not the "physical" ranges. Clean up some of the
bootstrap code in the process.

Submitted by: Peter Grehan <peterg@ptree32.com.au>

Implement the following functions:
- pmap_addr_hint
- pmap_change_wiring
- pmap_extract
- pmap_is_modified

Improve our detection of an attempted duplicate entry. We may be trying to
change the page protection bits.

1. Better track the executable status of mappings.
2. Set a pcpu variable to the real address of the active pmap (used when
exiting from traps.

Obtained from: NetBSD (1)

Tidy up some loose ends.
i386/ia64/alpha - catch up to sparc64/ppc:
- replace pmap_kernel() with refs to kernel_pmap
- change kernel_pmap pointer to (&kernel_pmap_store)
(this is a speedup since ld can set these at compile/link time)
all platforms (as suggested by jake):
- gc unused pmap_reference
- gc unused pmap_destroy
- gc unused struct pmap.pm_count
(we never used pm_count - we track address space sharing at the vmspace)

Correct a comment.

Implement the following functions:
- pmap_kextract
- pmap_object_init_pt
- pmap_protect
- pmap_remove_pages

I'm pretty sure pmap_remove_pages is at least somewhat bogus.

Remove some dead code.

Use mtsrin() instead of inline asm.

Change the value of PMAP_BOOTSTRAP so we don't stomp on the PTE index value.

Pass vm_page_t instead of physical addresses to pmap_zero_page[_area]()
and pmap_copy_page(). This gets rid of a couple more physical addresses
in upper layers, with the eventual aim of supporting PAE and dealing with
the physical addressing mostly within pmap. (We will need either 64 bit
physical addresses or page indexes, possibly both depending on the
circumstances. Leaving this to pmap itself gives more flexibilitly.)

Reviewed by: jake
Tested on: i386, ia64 and (I believe) sparc64. (my alpha was hosed)

Turn some CTR's into CTR0's.

Remove references to vm_zone.h and switch over to the new uma API.

Increment pmap_pvo_count in the right place.

This is the first part of the new kernel memory allocator. This replaces
malloc(9) and vm_zone with a slab like allocator.

Reviewed by: arch@

Changes and fixes in preparation for UMA:

- Bootstrap pvo entries are now allocated by stealing pages.
- Just return if we're pmap_enter'ing a mapping that's already there. Don't
remove it and re-enter it.

Correct a typo. (* that should've been &)

Copy the "implementation" of pmap_prefault from sparc64.

Calculate physmem.

- Modify pmap_activate so it only marks the pmap as active.
- Add a pmap_deactivate function.

Implement the following functions:
- pmap_remove
- pmap_kremove
- pmap_qremove

Remove most of the usage of critical_enter/exit.

I put these in to match the use of spl*() in the NetBSD code I was basing this
on, but it appears to cause problems.

I'm doing this in a separate commit so as to be able to refer back if locking
becomes an issue at a later stage.

Fix a horribly suboptimal algorithm in the vm_daemon.

In order to determine what to page out, the vm_daemon checks
reference bits on all pages belonging to all processes. Unfortunately,
the algorithm used reacted badly with shared pages; each shared page
would be checked once per process sharing it; this caused an O(N^2)
growth of tlb invalidations. The algorithm has been changed so that
each page will be checked only 16 times.

Prior to this change, a fork/sleepbomb of 1300 processes could cause
the vm_daemon to take over 60 seconds to complete, effectively
freezing the system for that time period. With this change
in place, the vm_daemon completes in less than a second. Any system
with hundreds of processes sharing pages should benefit from this change.

Note that the vm_daemon is only run when the system is under extreme
memory pressure. It is likely that many people with loaded systems saw
no symptoms of this problem until they reached the point where swapping
began.

Special thanks go to dillon, peter, and Chuck Cranor, who helped me
get up to speed with vm internals.

PR: 33542, 20393
Reviewed by: dillon
MFC after: 1 week

Don't call critical_enter()/critical_exit() around calls to pmap_pvo_enter()
as it does it's own handling of critical sections.

Complete rework of the PowerPC pmap and a number of other bits in the early
boot sequence.

The new pmap.c is based on NetBSD's newer pmap.c (for the mpc6xx processors)
which is 70% faster than the older code that the original pmap.c was based
on. It has also been based on the framework established by jake's initial
sparc64 pmap.c.

There is no change to how far the kernel gets (it makes it to the mountroot
prompt in psim) but the new pmap code is a lot cleaner.

Obtained from: NetBSD (pmap code)

Fix includes based on recent changes to lock.h, mutex.h and ktr.h.

Implement pmap_mapdev.

Add missing include file.

Use BATL/BATU macros instead of hardcoded hex constants.

Update PowerPC MD code to compile and do initial bootstrap based on
recent changes (KSE and VM requiring physmem to be setup).

Reviewed by: benno, jhb, julian

KSE Milestone 2
Note ALL MODULES MUST BE RECOMPILED
make the kernel aware that there are smaller units of scheduling than the
process. (but only allow one thread per process at this time).
This is functionally equivalent to teh previousl -current except
that there is a thread associated with each process.

Sorry john! (your next MFC will be a doosie!)

Reviewed by: peter@freebsd.org, dillon@freebsd.org

X-MFC after: ha ha ha ha

Similar to changes on i386/alpha/etc pmap.c; converge on a similar
look/feel on pmap_new_proc() with some cosmetic style changes.

Make PMAP_SHPGPERPROC tunable. One shouldn't need to recompile a kernel
for this, since it is easy to run into with large systems with lots of
shared mmap space.

Obtained from: yahoo

Forced commit due to mishap in the previous commit.

Add in an implementation of pmap_new_proc.

Fix comment breakage.

Bring in NetBSD code used in the PowerPC port.

Reviewed by: obrien, dfr
Obtained from: NetBSD