data structure called kse_upcall to manage UPCALL. All KSE binding
and loaning code are gone.
A thread owns an upcall can collect all completed syscall contexts in
its ksegrp, turn itself into UPCALL mode, and takes those contexts back
to userland. Any thread without upcall structure has to export their
contexts and exit at user boundary.
Any thread running in user mode owns an upcall structure, when it enters
kernel, if the kse mailbox's current thread pointer is not NULL, then
when the thread is blocked in kernel, a new UPCALL thread is created and
the upcall structure is transfered to the new UPCALL thread. if the kse
mailbox's current thread pointer is NULL, then when a thread is blocked
in kernel, no UPCALL thread will be created.
Each upcall always has an owner thread. Userland can remove an upcall by
calling kse_exit, when all upcalls in ksegrp are removed, the group is
atomatically shutdown. An upcall owner thread also exits when process is
in exiting state. when an owner thread exits, the upcall it owns is also
removed.
KSE is a pure scheduler entity. it represents a virtual cpu. when a thread
is running, it always has a KSE associated with it. scheduler is free to
assign a KSE to thread according thread priority, if thread priority is changed,
KSE can be moved from one thread to another.
When a ksegrp is created, there is always N KSEs created in the group. the
N is the number of physical cpu in the current system. This makes it is
possible that even an userland UTS is single CPU safe, threads in kernel still
can execute on different cpu in parallel. Userland calls kse_create to add more
upcall structures into ksegrp to increase concurrent in userland itself, kernel
is not restricted by number of upcalls userland provides.
The code hasn't been tested under SMP by author due to lack of hardware.
Reviewed by: julian
1.) Fix an off-by-one in the DVMA space handling, which would make it
possible to allocate one page beyond the end of the DVMA area.
This page was aliased to the first page. Apparently, this bug was
responsible for the trashed nvram/eeprom some people were reporting,
in conjunction with a number of unfortunate coincidences.
2.) Fix broken boundary and and lowaddr calculations.
3.) Fix a memory leak on an error path.
4.) Update a outdated comment to reflect the introduction of IOMMU_MAX_PRE,
make the usage of IOMMU_MAX_PRE more consistent and KASSERT that the
preallocation size is not 0.
5.) Fix a case where an error return was lost.
6.) When signalling an error to the caller by invoking the callback, do
not use a segment pointer of NULL for compatability with existing
drivers.
Also, increase the maximum segment number to 64; it is rather arbitrary,
with the exception of the of the stack space consumed by the segment
array.
Special thanks go to Harti Brandt <brandt@fokus.fraunhofer.de> for
spotting 4 and 5, and testing many iterations of patches.
Pointy hats to: tmm
constants where flag bits (as in NetBSD), although they are consecutively
numbered in FreeBSD. This would cause unnecessary flushing in the
BUS_DMASYNC_POSTWRITE case, but was otherwise mostly harmless.
indicate that uma_small_alloc should not. This code should be refactored so
that there is not so much cross arch duplication.
Reviewed by: jake
Spotted by: tmm
Tested on: alpha, sparc64
Pointy hat to: jeff and everyone who cut and pasted the bad code. :-)
metadata. This fixes module dependency resolution by the kernel linker on
sparc64, where the relocations for the metadata are different than on other
architectures; the relative offset is in the addend of an Elf_Rela record
instead of the original value of the location being patched.
Also fix printf formats in debug code.
Submitted by: Hartmut Brandt <brandt@fokus.gmd.de>
PR: 46732
Tested on: alpha (obrien), i386, sparc64
portable copy. Note that pmap_extract() must be used instead of
pmap_kextract().
This is precursor work to a reorganization of vmapbuf() to close remaining
user/kernel races (which can lead to a panic).
map. Use this new feature to implement iommu_dvmamap_load_mbuf() and
iommu_dvmamap_load_uio() functions in terms of a new helper function,
iommu_dvmamap_load_buffer(). Reimplement the iommu_dvmamap_load()
to use it, too.
This requires some changes to the map format; in addition to that,
remove unused or redundant members.
Add SBus and Psycho wrappers for the new functions, and make them
available through the respective DMA tags.
_nexus_dmamap_load_buffer()
- implement nexus_dmamap_load() in terms of _nexus_dmamap_load_buffer().
Note that this is untested, as this code is not currently used (but
might be later for UPA devices).
- move BUS_DMAMAP_NSEGS to bus_private.h
- disable the ecache flushing in nexus_dmamap_sync(); it should not be
needed, although the docs are not entirely clear on that.
- move some constants into iommureg.h
- correct some comments
- use KASSERT() in one place instead of rolling our own
- take a sanity check out of #ifdef DIAGNOSTIC
- fix a syntax error in normally #ifdef'ed out debug code
- tweak the announce message a bit
- remove '\n's from a few panic() calls
- don't use the DVMA base adress the firmware reports; instead, figure
it out from the appropriate register on Sabres and let the IOMMU code
choose it on Psychos. This also makes the IOMMU TSB size freely
selectable.
2.) pass the requesting child device (instead of the bus one) up when
handling interrupt resources
3.) remeber to mark the resource list entry as unused in
sbus_release_resource().
Reported by: scottl (3)
With a 1 byte transmit fifo, 3 byte receive fifo, and wierd multiplexed I/O
designed for a Z80 cpu, this chip redefines suckage.
Based on the openbsd and netbsd drivers. Only really works as a console,
modem support is not complete since I can't test it.
- Restore %g6 and %g7 for kernel traps if we are returning to prom code.
This allows complex traps (ones that call into C code) to be handled from
the prom.
be used for zones that allocate objects of less 1 page. The biggest advantage
of this is that all of a sudden the majority of kernel malloc-ed data doesn't
need kva allocated for it. Besides microbenchmarks I haven't seen a measurable
performance improvement from doing this.
useful for accessing more than 1 page of contiguous physical memory, and
to use 4mb tlb entries instead of 8k. This requires that the system only
use the direct mapped addresses when they have the same virtual colour as
all other mappings of the same page, instead of being able to choose the
colour and cachability of the mapping.
- Adapt the physical page copying and zeroing functions to account for not
being able to choose the colour or cachability of the direct mapped
address. This adds a lot more cases to handle. Basically when a page has
a different colour than its direct mapped address we have a choice between
bypassing the data cache and using physical addresses directly, which
requires a cache flush, or mapping it at the right colour, which requires
a tlb flush. For now we choose to map the page and do the tlb flush.
This will allows the direct mapped addresses to be used for more things
that don't require normal pmap handling, including mapping the vm_page
structures, the message buffer, temporary mappings for crash dumps, and will
provide greater benefit for implementing uma_small_alloc, due to the much
greater tlb coverage.
- Put the kernel tsb before before the kernel load address, below
VM_MIN_KERNEL_ADDRESS, instead of after the kernel where it consumes
usable kva. This is magic mapped so the virtual address is irrelevant,
it just needs to be out of the way.
a mapping belongs to by setting it in the vm_page_t structure that backs
the tsb page that the tte for a mapping is in. This allows the pmap that
a mapping belongs to to be found without keeping a pointer to it in the
tte itself.
- Remove the pmap pointer from struct tte and use the space to make the
tte pv lists doubly linked (TAILQs), like on other architectures. This
makes entering or removing a mapping O(1) instead of O(n) where n is the
number of pmaps a page is mapped by (including kernel_pmap).
- Use atomic ops for setting and clearing bits in the ttes, now that they
return the old value and can be easily used for this purpose.
- Use __builtin_memset for zeroing ttes instead of bzero, so that gcc will
inline it (4 inline stores using %g0 instead of a function call).
- Initially set the virtual colour for all the vm_page_ts to be equal to their
physical colour. This will be more useful once uma_small_alloc is
implemented, but basically pages with virtual colour equal to phsyical
colour are easier to handle at the pmap level because they can be safely
accessed through cachable direct virtual to physical mappings with that
colour, without fear of causing illegal dcache aliases.
In total these changes give a minor performance improvement, about 1%
reduction in system time during buildworld.
