Replace tlb_flush_local() by tlb_flush() as even not global mappings
could be fetched to TLB(s) on other cores by speculative table walk.
From OS point of view, it was not a problem as either such mappings
were not used anymore or they were flushed from TLB(s) when reused.
However, from hardware point of view, it was a problem. Not flushed
mappings could be a target for speculative reads or prefetches (which
might be quite aggresive on ARM cores). As speculative read can fill
cacheline, it can cause a real problem, when physical page is reused,
but mapped with different memory attributes.
Anyhow, it's good to have only valid mappings in TLB(s).
Approved by: kib (mentor)
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>
The MD allocators were very common, however there were some minor
differencies. These differencies were all consolidated in the MI allocator,
under ifdefs. The defines from machine/vmparam.h turn on features required
for a particular machine. For details look in the comment in sys/sf_buf.h.
As result no MD code left in sys/*/*/vm_machdep.c. Some arches still have
machine/sf_buf.h, which is usually quite small.
Tested by: glebius (i386), tuexen (arm32), kevlo (arm32)
Reviewed by: kib
Sponsored by: Netflix
Sponsored by: Nginx, Inc.
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
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.
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.
