Previously we used pmap_kremove(), but with ARM_NEW_PMAP it does the remove
in a way that isn't SMP-coherent (which is appropriate in some circumstances
such as mapping/unmapping sf buffers). With matching enter/remove routines
for device mappings, each low-level implementation can do the right thing.
Reviewed by: Svatopluk Kraus <onwahe@gmail.com>
This is pretty much a complete rewrite based on the existing i386 code. The
patches have been circulating for a couple years and have been looked at by
plenty of people, but I'm not putting anybody on the hook as having reviewed
this in any formal sense except myself.
After this has gotten wider testing from the user community, ARM_NEW_PMAP
will become the default and various dregs of the old pmap code will be
removed.
Submitted by: Svatopluk Kraus <onwahe@gmail.com>,
Michal Meloun <meloun@miracle.cz>
never actually ran on these chips (other than using SA1 support in an
emulator to do the early porting to FreeBSD long long ago). The clutter
and complexity of some of this code keeps getting in the way of other
maintenance, so it's time to go.
Invalidate L1 PTE regardles of existance of the corresponding
l2_bucket. This is relevant when superpage is entered via
pmap_enter_object() and will fix crash on entering page
in place of not properly removed superpage.
This was an optimization used only by a few xscale platforms. Part of
the optimization was to create a direct map for all physical pages, and
that resulted in making multiple mappings of pages in a way that bypassed
the logic in pmap.c to handle VIVT cache aliasing. It also just generally
made the code more complex and hard to maintain for all SoCs.
Reviewed by: cognet
new devmap.[ch] files. Emphasize the MD nature of these things by using
the prefix arm_devmap_ on the function and type names (already a few of
these things found their way into MI code, hopefully it will be harder to
do by accident in the future).
out common code related to mapping device memory into a new devmap.c file.
Remove the growing duplication of code that used pmap_devmap_find_pa() and
then did some math with the returned results to generate a virtual address,
and likewise in reverse to get a physical address. Now there are a pair
of functions, arm_devmap_vtop() and arm_devmap_ptov(), to do that. The
bus_space_map() implementations are rewritten in terms of these.
Use values of the correct defines to determine statement's result.
ARM_ARCH_ symbols are always defined, hence only values are relevant.
Reviewed by: cognet
The only remaining user was the code that allocates bounce pages for armv4
busdma. It's not clear why bounce pages would need uncached memory, but
if that ever changes, kmem_alloc_attr() would be the way to get it.
Promoting base pages to superpages can increase TLB coverage and allow for
efficient use of page table entries. This development provides FreeBSD/ARM
with superpages management mechanism roughly equivalent to what we have for
i386 and amd64 architectures.
1. Add mechanism for automatic promotion of 4KB page mappings to 1MB section
mappings (and demotion when not needed, respectively).
2. Managed and non-kernel mappings are now superpages-aware.
3. The functionality can be enabled by setting "vm.pmap.sp_enabled" tunable to
a non-zero value (either in loader.conf or by modifying "sp_enabled"
variable in pmap-v6.c file). By default, automatic promotion is currently
disabled.
Submitted by: Zbigniew Bodek <zbb@semihalf.com>
Reviewed by: alc
Sponsored by: The FreeBSD Foundation, Semihalf
Revise L2_S_PROT_MASK to include all of the protection bits. Notice that
clearing these bits does not always take away the corresponding permissions
(for example, permission is granted when the bit is cleared). The bits are
cleared but are to be set or left cleared accordingly in pmap_set_prot(),
pmap_enter_locked(), etc.
Clear L2_XN along with L2_S_PROT_MASK in pmap_set_prot() so that all
permissions related bits are cleared before actual configuration.
Submitted by: Zbigniew Bodek <zbb@semihalf.com>
Reviewed by: gber
Sponsored by: The FreeBSD Foundation, Semihalf
Using PVF_MOD, PVF_REF and PVF_EXEC is redundant as we can get the proper
info from PTE bits.
When the mapping is marked as executable and has been referenced we assume
that it has been executed. Similarly, when the mapping is set to be writable
and is referenced, it must have been due to write access to it.
PVF_MOD and PVF_REF flags are kept just for pmap_clearbit() usage,
to pass the information on which bit should be cleared.
Submitted by: Zbigniew Bodek <zbb@semihalf.com>
Sponsored by: The FreeBSD Foundation, Semihalf
Use pmap_find_pv if needed instead of multiplying its code throughout
pmap-v6.
Avoid possible NULL pointer dereference in pmap_enter_locked()
When trying to get m->md.pv_memattr, make sure that m != NULL,
in particular that vector_page is set to be NULL.
Do not set PGA_REFERENCED flag in pmap_enter_pv().
On ARM any new page reference will result in either entering the new
mapping by calling pmap_enter, etc. or fixing-up the existing mapping in
pmap_fault_fixup().
Therefore we set PGA_REFERENCED flag in the earlier mentioned cases and
setting it later in pmap_enter_pv() is just waste of cycles.
Delete unused pm_pdir pointer from the pmap structure.
Rearrange brackets in the fault cause detection in trap.c
Place the brackets correctly in order to see course of the conditions
instantaneously.
Unify naming in pmap-v6.c and improve style
Use naming common for whole pmap and compatible with other pmaps,
improve style where possible:
pm -> pmap
pg -> m
opg -> om
*pt -> *ptep
*pte -> *ptep
*pde -> *pdep
Submitted by: Zbigniew Bodek <zbb@semihalf.com>
Sponsored by: The FreeBSD Foundation, Semihalf
bit in PTE.
Enable Access Flag in CPU control. With AF enabled each valid mapping
needs to have referenced bit in PTE set in order to be able to cache
it in the TLB.
AP[0] bit is to be used as reference flag.
All access permissions are encoded by AP[2:1] wherein AP[1] is in fact
"user enable" and AP[2](APX) is "write disable".
All mappings are always set to be valid. Reference emulation is performed
by setting/clearing reference flag in PTE.
md.pvh_attrs are no longer necessary however pv_flags are still being used
for now.
Marking vm_page as "dirty" or "referenced" is being performed on:
- page or flag fault servicing in pmap_fault_fixup(), basing on the fault
type
- vm_fault servicing in pmap_enter() according to the desired protections
and faulty access type
Redundant page marking has been removed as on ARM we know exactly when the
particular page is referenced or is going to be written.
Submitted by: Zbigniew Bodek <zbb@semihalf.com>
Sponsored by: The FreeBSD Foundation, Semihalf
PV entries are now roughly half the size.
Instead of using a shared UMA zone for 28 byte pv entries
(two 8-byte tailq nodes, a 4 byte pointer, a 4 byte address and 4 byte
flags), we allocate a page at a time per process.
This provides 252 pv entries per process (actually, per pmap address space)
and eliminates one of the 8-byte tailq entries since we now can track
per-process pv entries implicitly.
The pointer to the pmap can be eliminated by doing address arithmetic to
find the metadata on the page headers to find a single pointer shared by
all 252 entries. There is an 8-int bitmap for the freelist of those 252
entries.
When in serious low memory condition, allocation of another pv_chunk is
possible by freeing some pages in pmap_pv_reclaim().
Added pv_entry/pv_chunk related statistics to pmap.
pv_entry/pv_chunk statistics can be accessed via sysctl vm.pmap.
Ported PTE freelist of KVA allocation and maintenance from i386.
Using an idea from Stephan Uphoff, use the empty pte's that correspond
to the unused kva in the pv memory block to thread a freelist through.
This allows us to free pages that used to be used for pv entry chunks
since we can now track holes in the kva memory block.
As both ARM pmap.c and pmap-v6.c use the same header and pv_entry, pmap and
md_page structures are different, it was needed to separate code designed
for ARMv6/7 from the one for other ARMs.
Submitted by: Zbigniew Bodek <zbb@semihalf.com>
Reviewed by: alc
Sponsored by: The FreeBSD Foundation, Semihalf
Keep following access permissions:
APX AP Kernel User
1 01 R N
1 10 R R
0 01 R/W N
0 11 R/W R/W
Avoid using reserved in ARMv6 APX|AP settings:
- In case of unprivileged (user) access without permission to write,
the access permission bits were being set to reserved for ARMv6
(but valid for ARMv7) value of APX|AP = 111.
Fix-up faulting userland accesses properly:
- Wrong condition statement in pmap_fault_fixup() caused that
any genuine, unprivileged access was being fixed-up instead of
just skip doing anything and return. Staring from now we ensure
proper reaction for illicit user accesses.
L2_S_PROT_R and L2_S_PROT_U names might be misleading as they do not
reflect real permission levels. It will be clarified in following
patches (switch to AP[2:1] permissions model).
Obtained from: Semihalf
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
problematic because some callers to pmap_kextract() expect its
implementation to be lock-less. In particular, uma_dbg_alloc() implicitly
requires this. Otherwise, lock-order reversals occur between pmap locks and
UMA zone locks. So, this change introduces a lock-less implementation of
pmap_kextract().
Disable recursion on the pvh global lock in the new armv6 pmap. While
recursion on this locks occurs in the old arm pmap, it thankfully doesn't
occur in the armv6 pmap.
Tested by: jmg
Cummulative patch of changes that are not vendor-specific:
- ARMv6 and ARMv7 architecture support
- ARM SMP support
- VFP/Neon support
- ARM Generic Interrupt Controller driver
- Simplification of startup code for all platforms
layer, but it is read directly by the MI VM layer. This change introduces
pmap_page_is_write_mapped() in order to completely encapsulate all direct
access to PGA_WRITEABLE in the pmap layer.
Aesthetics aside, I am making this change because amd64 will likely begin
using an alternative method to track write mappings, and having
pmap_page_is_write_mapped() in place allows me to make such a change
without further modification to the MI VM layer.
As an added bonus, tidy up some nearby comments concerning page flags.
Reviewed by: kib
MFC after: 6 weeks
- Write Buffers have to be drained after write to Page Table even if caches
are in write-through mode.
- Make sure to sync PTE in pmap_zero_page_generic().
Submitted by: Michal Mazur
Reviewed by: cognet
Obtained from: Semihalf
MFC after: 1 month
cpuset_t objects.
That is going to offer the underlying support for a simple bump of
MAXCPU and then support for number of cpus > 32 (as it is today).
Right now, cpumask_t is an int, 32 bits on all our supported architecture.
cpumask_t on the other side is implemented as an array of longs, and
easilly extendible by definition.
The architectures touched by this commit are the following:
- amd64
- i386
- pc98
- arm
- ia64
- XEN
while the others are still missing.
Userland is believed to be fully converted with the changes contained
here.
Some technical notes:
- This commit may be considered an ABI nop for all the architectures
different from amd64 and ia64 (and sparc64 in the future)
- per-cpu members, which are now converted to cpuset_t, needs to be
accessed avoiding migration, because the size of cpuset_t should be
considered unknown
- size of cpuset_t objects is different from kernel and userland (this is
primirally done in order to leave some more space in userland to cope
with KBI extensions). If you need to access kernel cpuset_t from the
userland please refer to example in this patch on how to do that
correctly (kgdb may be a good source, for example).
- Support for other architectures is going to be added soon
- Only MAXCPU for amd64 is bumped now
The patch has been tested by sbruno and Nicholas Esborn on opteron
4 x 12 pack CPUs. More testing on big SMP is expected to came soon.
pluknet tested the patch with his 8-ways on both amd64 and i386.
Tested by: pluknet, sbruno, gianni, Nicholas Esborn
Reviewed by: jeff, jhb, sbruno
quite right and hasn't been used in ages and is likely broken. QEMU
with GUMSTIX is a more promising road to FreeBSD/arm in emulation
anyway.
Reviewed by: cognet@
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
dependent memory attributes:
Rename vm_cache_mode_t to vm_memattr_t. The new name reflects the
fact that there are machine-dependent memory attributes that have
nothing to do with controlling the cache's behavior.
Introduce vm_object_set_memattr() for setting the default memory
attributes that will be given to an object's pages.
Introduce and use pmap_page_{get,set}_memattr() for getting and
setting a page's machine-dependent memory attributes. Add full
support for these functions on amd64 and i386 and stubs for them on
the other architectures. The function pmap_page_set_memattr() is also
responsible for any other machine-dependent aspects of changing a
page's memory attributes, such as flushing the cache or updating the
direct map. The uses include kmem_alloc_contig(), vm_page_alloc(),
and the device pager:
kmem_alloc_contig() can now be used to allocate kernel memory with
non-default memory attributes on amd64 and i386.
vm_page_alloc() and the device pager will set the memory attributes
for the real or fictitious page according to the object's default
memory attributes.
Update the various pmap functions on amd64 and i386 that map pages to
incorporate each page's memory attributes in the mapping.
Notes: (1) Inherent to this design are safety features that prevent
the specification of inconsistent memory attributes by different
mappings on amd64 and i386. In addition, the device pager provides a
warning when a device driver creates a fictitious page with memory
attributes that are inconsistent with the real page that the
fictitious page is an alias for. (2) Storing the machine-dependent
memory attributes for amd64 and i386 as a dedicated "int" in "struct
md_page" represents a compromise between space efficiency and the ease
of MFCing these changes to RELENG_7.
In collaboration with: jhb
Approved by: re (kib)
structure. When the page is shared, the kernel mapping becomes a special
type of managed page to force the cache off the page mappings. This is
needed to avoid stale entries on all ARM VIVT caches, and VIPT caches
with cache color issue.
Submitted by: Mark Tinguely
Reviewed by: alc
Tested by: Grzegorz Bernacki, thompsa
The only downside is that it renames pmap_vac_me_harder() to pmap_fix_cache().
From Mark's email on -arm :
pmap_get_vac_flags(), pmap_vac_me_harder(), pmap_vac_me_kpmap(), and
pmap_vac_me_user() has been rewritten as pmap_fix_cache() to be more
efficient in the kernel map case. I also removed the reference to
the md.kro_mappings, md.krw_mappings, md.uro_mappings, and md.urw_mappings
counts.
In pmap_clearbit(), we can also skip over tests and writeback/invalidations
in the PVF_MOD and PVF_REF cases if those bits are not set in the pv_flag.
PVF_WRITE will turn caching back on and remove the PV_MOD bit.
In pmap_nuke_pv(), the vm_page_flag_clear(pg, PG_WRITEABLE) has been moved
to the pmap_fix_cache().
We can be more agressive in attempting to turn caching back on by calling
pmap_fix_cache() at times that may be appropriate to turn cache on
(a kernel mapping has been removed, a write has been removed or a read
has been removed and we know the mapping does not have multiple write
mappings to a page).
In pmap_remove_pages() the cpu_idcache_wbinv_all() is moved to happen
before the page tables are NULLed because the caches are virtually
indexed and virtually tagged.
In pmap_remove_all(), the pmap_remove_write(m) is added before the
page tables are NULLed because the caches are virtually indexed and
virtually tagged. This also removes the need for the caches fixing routine
(whichever is being used pmap_vac_me_harder() or pmap_fix_cache()) to be
called on any of these mappings.
In pmap_remove(), I simplified the cache cleaning process and removed
extra TLB removals. Basically if more than PMAP_REMOVE_CLEAN_LIST_SIZE
are removed, then just flush the entire cache.
