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Author SHA1 Message Date
Vineet Gupta
301014cf6d ARC: atomic_cmpxchg/atomic_xchg: implement relaxed variants
And move them out of cmpxchg.h to canonical atomic.h

Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Vineet Gupta <vgupta@kernel.org>
2021-08-24 14:25:47 -07:00
Vineet Gupta
ddc348c44d ARC: cmpxchg/xchg: implement relaxed variants (LLSC config only)
It only makes sense to do this for the LLSC config

Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Vineet Gupta <vgupta@kernel.org>
2021-08-24 14:25:47 -07:00
Vineet Gupta
e188f3330a ARC: cmpxchg/xchg: rewrite as macros to make type safe
Existing code forces/assume args to type "long" which won't work in LP64
regime, so prepare code for that

Interestingly this should be a non functional change but I do see
some codegen changes

| bloat-o-meter vmlinux-cmpxchg-A vmlinux-cmpxchg-B
| add/remove: 0/0 grow/shrink: 17/12 up/down: 218/-150 (68)
|
| Function                                     old     new   delta
| rwsem_optimistic_spin                        518     550     +32
| rwsem_down_write_slowpath                   1244    1274     +30
| __do_sys_perf_event_open                    2576    2600     +24
| down_read                                    192     200      +8
| __down_read                                  192     200      +8
...
| task_work_run                                168     148     -20
| dma_fence_chain_walk.part                    760     736     -24
| __genradix_ptr_alloc                         674     646     -28

Total: Before=6187409, After=6187477, chg +0.00%

Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Vineet Gupta <vgupta@kernel.org>
2021-08-24 14:25:47 -07:00
Vineet Gupta
ecf51c9fa0 ARC: xchg: !LLSC: remove UP micro-optimization/hack
It gets in the way of cleaning things up and is a maintenance
pain-in-neck !

Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Vineet Gupta <vgupta@kernel.org>
2021-08-24 14:25:47 -07:00
Linus Torvalds
a15286c63d Locking changes for this cycle:
- Core locking & atomics:
 
      - Convert all architectures to ARCH_ATOMIC: move every
        architecture to ARCH_ATOMIC, then get rid of ARCH_ATOMIC
        and all the transitory facilities and #ifdefs.
 
        Much reduction in complexity from that series:
 
            63 files changed, 756 insertions(+), 4094 deletions(-)
 
      - Self-test enhancements
 
  - Futexes:
 
      - Add the new FUTEX_LOCK_PI2 ABI, which is a variant that
        doesn't set FLAGS_CLOCKRT (.e. uses CLOCK_MONOTONIC).
 
        [ The temptation to repurpose FUTEX_LOCK_PI's implicit
          setting of FLAGS_CLOCKRT & invert the flag's meaning
          to avoid having to introduce a new variant was
          resisted successfully. ]
 
      - Enhance futex self-tests
 
  - Lockdep:
 
      - Fix dependency path printouts
      - Optimize trace saving
      - Broaden & fix wait-context checks
 
  - Misc cleanups and fixes.
 
 Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'locking-core-2021-06-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull locking updates from Ingo Molnar:

 - Core locking & atomics:

     - Convert all architectures to ARCH_ATOMIC: move every architecture
       to ARCH_ATOMIC, then get rid of ARCH_ATOMIC and all the
       transitory facilities and #ifdefs.

       Much reduction in complexity from that series:

           63 files changed, 756 insertions(+), 4094 deletions(-)

     - Self-test enhancements

 - Futexes:

     - Add the new FUTEX_LOCK_PI2 ABI, which is a variant that doesn't
       set FLAGS_CLOCKRT (.e. uses CLOCK_MONOTONIC).

       [ The temptation to repurpose FUTEX_LOCK_PI's implicit setting of
         FLAGS_CLOCKRT & invert the flag's meaning to avoid having to
         introduce a new variant was resisted successfully. ]

     - Enhance futex self-tests

 - Lockdep:

     - Fix dependency path printouts

     - Optimize trace saving

     - Broaden & fix wait-context checks

 - Misc cleanups and fixes.

* tag 'locking-core-2021-06-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (52 commits)
  locking/lockdep: Correct the description error for check_redundant()
  futex: Provide FUTEX_LOCK_PI2 to support clock selection
  futex: Prepare futex_lock_pi() for runtime clock selection
  lockdep/selftest: Remove wait-type RCU_CALLBACK tests
  lockdep/selftests: Fix selftests vs PROVE_RAW_LOCK_NESTING
  lockdep: Fix wait-type for empty stack
  locking/selftests: Add a selftest for check_irq_usage()
  lockding/lockdep: Avoid to find wrong lock dep path in check_irq_usage()
  locking/lockdep: Remove the unnecessary trace saving
  locking/lockdep: Fix the dep path printing for backwards BFS
  selftests: futex: Add futex compare requeue test
  selftests: futex: Add futex wait test
  seqlock: Remove trailing semicolon in macros
  locking/lockdep: Reduce LOCKDEP dependency list
  locking/lockdep,doc: Improve readability of the block matrix
  locking/atomics: atomic-instrumented: simplify ifdeffery
  locking/atomic: delete !ARCH_ATOMIC remnants
  locking/atomic: xtensa: move to ARCH_ATOMIC
  locking/atomic: sparc: move to ARCH_ATOMIC
  locking/atomic: sh: move to ARCH_ATOMIC
  ...
2021-06-28 11:45:29 -07:00
Mark Rutland
6db5d99304 locking/atomic: arc: move to ARCH_ATOMIC
We'd like all architectures to convert to ARCH_ATOMIC, as once all
architectures are converted it will be possible to make significant
cleanups to the atomics headers, and this will make it much easier to
generically enable atomic functionality (e.g. debug logic in the
instrumented wrappers).

As a step towards that, this patch migrates alpha to ARCH_ATOMIC. The
arch code provides arch_{atomic,atomic64,xchg,cmpxchg}*(), and common
code wraps these with optional instrumentation to provide the regular
functions.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Vineet Gupta <vgupta@synopsys.com>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20210525140232.53872-15-mark.rutland@arm.com
2021-05-26 13:20:50 +02:00
Bhaskar Chowdhury
f79f7a2d96 arc: Fix typos/spellos
s/commiting/committing/
s/defintion/definition/
s/gaurantees/guarantees/
s/interrpted/interrupted/
s/interrutps/interrupts/
s/succeded/succeeded/
s/unconditonally/unconditionally/

Reviewed-by: Christian Brauner <christian.brauner@ubuntu.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Bhaskar Chowdhury <unixbhaskar@gmail.com>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
2021-05-10 12:38:59 -07:00
Randy Dunlap
6364d1b41c arc: include/asm: fix typos of "themselves"
Fix copy/paste spello of "themselves" in 3 places.

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: linux-snps-arc@lists.infradead.org
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
2020-10-05 21:02:29 -07:00
Vineet Gupta
dd7c7ab01a ARC: [plat-eznps]: Drop support for EZChip NPS platform
NPS customers are no longer doing active development, as evident from
rand config build failures reported in recent times, so drop support
for NPS platform.

Tested-by: kernel test robot <lkp@intel.com>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
2020-10-05 21:02:29 -07:00
Thomas Gleixner
d2912cb15b treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500
Based on 2 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license version 2 as
  published by the free software foundation

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license version 2 as
  published by the free software foundation #

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-only

has been chosen to replace the boilerplate/reference in 4122 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Enrico Weigelt <info@metux.net>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190604081206.933168790@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-06-19 17:09:55 +02:00
Vineet Gupta
89c92142f7 ARC: fix build warnings
| arch/arc/mm/tlb.c:914:2: warning: variable length array 'pd0' is used [-Wvla]
| arch/arc/include/asm/cmpxchg.h:95:29: warning: value computed is not used [-Wunused-value]

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
2019-05-20 10:09:10 -07:00
Noam Camus
a5a10d99a9 ARC: [plat-eznps] Use dedicated atomic/bitops/cmpxchg
We need our own implementaions since we lack LLSC support.
Our extended ISA provided with optimized solution for all 32bit
operations we see in these three headers.
Signed-off-by: Noam Camus <noamc@ezchip.com>
2016-05-09 09:32:33 +05:30
Adam Buchbinder
7423cc0cae ARC: Fix misspellings in comments.
Signed-off-by: Adam Buchbinder <adam.buchbinder@gmail.com>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
2016-03-11 14:59:53 +05:30
Vineet Gupta
090749502f ARC: add/fix some comments in code - no functional change
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
2015-08-20 19:05:49 +05:30
Vineet Gupta
2576c28e3f ARC: add smp barriers around atomics per Documentation/atomic_ops.txt
- arch_spin_lock/unlock were lacking the ACQUIRE/RELEASE barriers
   Since ARCv2 only provides load/load, store/store and all/all, we need
   the full barrier

 - LLOCK/SCOND based atomics, bitops, cmpxchg, which return modified
   values were lacking the explicit smp barriers.

 - Non LLOCK/SCOND varaints don't need the explicit barriers since that
   is implicity provided by the spin locks used to implement the
   critical section (the spin lock barriers in turn are also fixed in
   this commit as explained above

Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: stable@vger.kernel.org
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
2015-06-25 06:00:16 +05:30
Vineet Gupta
d57f727264 ARC: add compiler barrier to LLSC based cmpxchg
When auditing cmpxchg call sites, Chuck noted that gcc was optimizing
away some of the desired LDs.

|	do {
|		new = old = *ipi_data_ptr;
|		new |= 1U << msg;
|	} while (cmpxchg(ipi_data_ptr, old, new) != old);

was generating to below

| 8015cef8:	ld         r2,[r4,0]  <-- First LD
| 8015cefc:	bset       r1,r2,r1
|
| 8015cf00:	llock      r3,[r4]  <-- atomic op
| 8015cf04:	brne       r3,r2,8015cf10
| 8015cf08:	scond      r1,[r4]
| 8015cf0c:	bnz        8015cf00
|
| 8015cf10:	brne       r3,r2,8015cf00  <-- Branch doesn't go to orig LD

Although this was fixed by adding a ACCESS_ONCE in this call site, it
seems safer (for now at least) to add compiler barrier to LLSC based
cmpxchg

Reported-by: Chuck Jordan <cjordan@synopsys,com>
Cc: <stable@vger.kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
2015-06-25 05:59:23 +05:30
Vineet Gupta
14e968bad7 ARC: Atomic/bitops/cmpxchg/barriers
This covers the UP / SMP (with no hardware assist for atomic r-m-w) as
well as ARC700 LLOCK/SCOND insns based.

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
2013-02-11 20:00:30 +05:30