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.
- Add a default parent dma tag, similar to what has been done for sparc64.
- Before invalidating the dcache in POSTREAD, save the bits which are in the
same cachelines than our buffers, but not part of it, and restore them after
the invalidation.
whole the physical memory, cached, using 1MB section mappings. This reduces
the address space available for user processes a bit, but given the amount of
memory a typical arm machine has, it is not (yet) a big issue.
It then provides a uma_small_alloc() that works as it does for architectures
which have a direct mapping.
Add a new option, SKYEYE_WORKAROUNDS, which as the name suggests adds
workarounds for things skyeye doesn't simulate. Specifically :
- Use USART0 instead of DBGU as the console, make it not use DMA, and manually provoke an interrupt when we're done in the transmit function.
- Skyeye maintains an internal counter for clock, but apparently there's
no way to access it, so hack the timecounter code to return a value which
is increased at every clock interrupts. This is gross, but I didn't find a
better way to implement timecounters without hacking Skyeye to get the
counter value.
- Force the write-back of PTEs once we're done writing them, even if they
are supposed to be write-through. I don't know why I have to do that.
with malloc() or contigmalloc() as usual, but try to re-map the allocated
memory into a VA outside the KVA, non-cached, thus making the calls to
bus_dmamap_sync() for these buffers useless.
Move what can be moved (UMA zones creation, pv_entry_* initialization) from
pmap_init2() to pmap_init().
Create a new function, pmap_postinit(), called from cpu_startup(), to do the
L1 tables allocation.
pmap_init2() is now empty for arm as well.
ARM_TP_ADDRESS, where the tp will be stored. On CPUs that support it, a cache
line will be allocated and locked for this address, so that it will never go
to RAM. On CPUs that does not, a page is allocated for it (it will be a bit
slower, and is wrong for SMP, but should be fine for UP).
The tp is still stored in the mdthread struct, and at each context switch,
ARM_TP_ADDRESS gets updated.
Suggested by: davidxu
Remove the cache state logic : right now, it provides more problems than it
helps.
Add helper functions for mapping devices while bootstrapping.
Reorganize the code a bit, and remove dead code.
Obtained from: NetBSD (partially)
It only supports sa1110 (on simics) right now, but xscale support should come
soon.
Some of the initial work has been provided by :
Stephane Potvin <sepotvin at videotron.ca>
Most of this comes from NetBSD.
