CVS log for src/sys/arch/mips/include/lock.h

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Default branch: MAIN

mips: Convert lock.h to membar_release/acquire.

mips: Brush up __cpu_simple_lock.

- Eradicate last vestiges of mb_* barriers.

- In __cpu_simple_lock_init, omit needless barrier.  It is the
  caller's responsibility to ensure __cpu_simple_lock_init happens
  before other operations on it anyway, so there was never any need
  for a barrier here.

- In __cpu_simple_lock_try, leave comments about memory ordering
  guarantees of the kernel's _atomic_cas_uint, which are inexplicably
  different from the non-underscored atomic_cas_uint.

- In __cpu_simple_unlock, use membar_exit instead of mb_memory, and do
  it unconditionally.

  This ensures that in __cpu_simple_lock/.../__cpu_simple_unlock, all
  memory operations in the ellipsis happen before the store that
  releases the lock.

  - On Octeon, the barrier was omitted altogether, which is a bug --
    it needs to be there or else there is no happens-before relation
    and whoever takes the lock next might see stale values stored or
    even stomp over the unlocking CPU's delayed loads.

  - On non-Octeon, the mb_memory was sync.  Using membar_exit
    preserves this.

  XXX On Octeon, membar_exit only issues syncw -- this seems wrong,
  only store-before-store and not load/store-before-store, unless the
  CNMIPS architecture guarantees it is sufficient here like
  SPARCv8/v9 PSO (`Partial Store Order').

- Leave an essay with citations about why we have an apparently
  pointless syncw _after_ releasing a lock, to work around a design
  bug^W^Wquirk in cnmips which sometimes buffers stores for hundreds
  of thousands of cycles for fun unless you issue syncw.

Indent branch delay slots in asm code (from skrll@).
Be consistent within this file with how asm code is formatted.

update from HEAD

more const.

Sync with HEAD

Rework cavium support in preparation for MULTIPROCESSOR support

Sync with HEAD.

sync with head

Sync with HEAD

Major merge forward from matt-nb5-mips64.
New fixup code.
New common SPL code.
New common interrupt code.
Move related variables into structures.
Cleanup locore (move MD variable into it).
Kill StudlyCaps
Use PCU for FPU

In SIMPLELOCK_LOCKED_P check against != UNLOCKED instead of == LOCKED.
This is so the compiler can emit a bnez instead of loading 1 into a register
and then doing beq.

sync with head.

Sync with HEAD.

Sync with HEAD.

Use userspace version unless _HARDKERNEL.  Otherwise we use atomic
cas to implement spinlocks and spinlocks to implement atomic cas....
which might suck.

Since the userspace version uses ll/sc, which doesn't exist on
R2000/R3000, rump will not work on those platforms.  *snif* (well,
pthread in general AFAICT).

Sync with HEAD.

sync with head.

sync with head.

Remove clause 3 and 4 from TNF licenses

sync with HEAD

Sync with HEAD.

sync with head

Sync with HEAD.

Sync with HEAD.

- Change _lock_cas and friends to do "compare and swap" instead of "compare
  and set".
- Rename them to _atomic_cas_uint, _atomic_cas_ulong etc and provide strong
  aliases for the other names CAS goes by.

sync with HEAD

sync with head.

Merge the ppcoea-renovation branch to HEAD.

This branch was a major cleanup and rototill of many of the various OEA
cpu based PPC ports that focused on sharing as much code as possible
between the various ports to eliminate near-identical copies of files in
every tree.  Additionally there is a new PIC system that unifies the
interface to interrupt code for all different OEA ppc arches.  The work
for this branch was done by a variety of people, too long to list here.

TODO:
bebox still needs work to complete the transition to -renovation.
ofppc still needs a bunch of work, which I will be looking at.
ev64260 still needs to be renovated
amigappc was not attempted.

NOTES:
pmppc was removed as an arch, and moved to a evbppc target.

Sync with head.

Sync with HEAD

Sync with HEAD.

Merge nick-csl-alignment.

Provide __SIMPLELOCK_{UN,}LOCKED_P and __cpu_simple_lock_{set,clear}
for all architectures.

sync with head.

Pacify lint/gcc.

s/___asm/__asm/

Merge newlock2 to head.

Make mips systems work.

Checkpoint work in progress.

sync with head

sync with head.

sync with head.

Sync with head.

Sync with head.

Adjust asm constraints for more pickier gcc4.

inline -> __inline

Remove leading __ from __(const|inline|signed|volatile) -- it is obsolete.

merge ktrace-lwp.

Fix the sync with head I botched.

Sync with HEAD.

Sync with HEAD

Move __cpu_simple_lock_t and __SIMPLELOCK_{UN,}LOCKED to machine/types.h
so that they can be used in a namespace-friendly way.

Sync with HEAD.

Drop the _KERNEL test; these functions are needed for SMP and other ports
don't bother with a _KERNEL check.

sync kqueue with -current; this includes merge of gehenna-devsw branch,
merge of i386 MP branch, and part of autoconf rototil work

Bring down from nathanw_sa branch.

Can't load the lock in the delay slot of its test.  Also explicitly
include delay slots according to common convention.

Fix branch instruction in delay slot.  Ooops!!

Add support for R4x00 locks using LL/SC.   Needed by new libpthread

As discussed on Mips mailing list there is no equivalent functionality
for R3000 processors. Restartable Atomic Sequences will be implemented
in the future to provide similar functionality on R3000 uniprocessor
machines.

Update thorpej_scsipi to -current as of a month ago
A i386 GENERIC kernel compiles without the siop, ahc and bha drivers
(will be updated later). i386 IDE/ATAPI and ncr work, as well as
sparc/esp_sbus. alpha should work as well (untested yet).
siop, ahc and bha will be updated once I've updated the branch to current
-current, as well as machine-dependant code.

file lock.h was added on branch thorpej_scsipi on 2000-11-20 20:13:31 +0000

Let each platform typedef the new __cpu_simple_lock_t, which should
be the most efficient type used for the atomic operations in the
simplelock structure, and should also be __volatile.

Require that each each MACHINE/MACHINE_ARCH supply a lock.h.  This file
contains the values __SIMPLELOCK_LOCKED and __SIMPLELOCK_UNLOCKED, which
replace the old SIMPLELOCK_LOCKED and SIMPLELOCK_UNLOCKED.  These files
are also required to supply inline functions __cpu_simple_lock(),
__cpu_simple_lock_try(), and __cpu_simple_unlock() if locking is to be
supported on that platform (i.e. if MULTIPROCESSOR is defined in the
_KERNEL case).  Change these functions to take an int * (&alp->lock_data)
rather than the struct simplelock * itself.

These changes make it possible for userland to use the locking primitives
by including <machine/lock.h>.