linux-stable.git/arch/arc/include/asm/atomic.h, branch linux-4.9.y

ARC: atomics: unbork atomic_fetch_##op()

2018-10-10T06:53:18+00:00

[ Upstream commit 3fcbb8260a87efb691d837e8cd24e81f65b3eb70 ]

In 4.19-rc1, Eugeniy reported weird boot and IO errors on ARC HSDK

| INFO: task syslogd:77 blocked for more than 10 seconds.
|       Not tainted 4.19.0-rc1-00007-gf213acea4e88 #40
| "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this
| message.
| syslogd         D    0    77     76 0x00000000
|
| Stack Trace:
|  __switch_to+0x0/0xac
|  __schedule+0x1b2/0x730
|  io_schedule+0x5c/0xc0
|  __lock_page+0x98/0xdc
|  find_lock_entry+0x38/0x100
|  shmem_getpage_gfp.isra.3+0x82/0xbfc
|  shmem_fault+0x46/0x138
|  handle_mm_fault+0x5bc/0x924
|  do_page_fault+0x100/0x2b8
|  ret_from_exception+0x0/0x8

He bisected to 84c6591103db ("locking/atomics,
asm-generic/bitops/lock.h: Rewrite using atomic_fetch_*()")

This commit however only unmasked the real issue introduced by commit
4aef66c8ae9 ("locking/atomic, arch/arc: Fix build") which missed the
retry-if-scond-failed branch in atomic_fetch_##op() macros.

The bisected commit started using atomic_fetch_##op() macros for building
the rest of atomics.

Fixes: 4aef66c8ae9 ("locking/atomic, arch/arc: Fix build")
Reported-by: Eugeniy Paltsev 
Acked-by: Peter Zijlstra (Intel) 
Signed-off-by: Will Deacon 
Signed-off-by: Vineet Gupta 
[vgupta: wrote changelog]
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

ARC: [plat-eznps] Fix build error

2017-05-03T15:36:38+00:00

commit 6492f09e864417d382e22b922ae30693a7ce2982 upstream.

Make ATOMIC_INIT available for all ARC platforms (including plat-eznps)

Signed-off-by: Noam Camus 
Signed-off-by: Vineet Gupta 
Signed-off-by: Greg Kroah-Hartman

ARC: [plat-eznps] add missing atomic_fetch_xxx operations

2016-09-30T21:48:18+00:00

Build brekeage since last changes to generic atomic operations.
Added couple of missing macros which are now mandatory

Signed-off-by: Noam Camus 
Signed-off-by: Vineet Gupta

ARCv2: Implement atomic64 based on LLOCKD/SCONDD instructions

2016-09-30T21:48:17+00:00

ARCv2 ISA provides 64-bit exclusive load/stores so use them to implement
the 64-bit atomics and elide the spinlock based generic 64-bit atomics

boot tested with atomic64 self-test (and GOD bless the person who wrote
them, I realized my inline assmebly is sloppy as hell)

Cc: Peter Zijlstra 
Cc: Will Deacon 
Cc: linux-snps-arc@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Vineet Gupta

locking/atomic, arch/arc: Fix build

2016-06-20T09:25:49+00:00

Resolve conflict between commits:

  fbffe892e525 ("locking/atomic, arch/arc: Implement atomic_fetch_{add,sub,and,andnot,or,xor}()")

and:

  ed6aefed726a ("Revert "ARCv2: spinlock/rwlock/atomics: Delayed retry of failed SCOND with exponential backoff"")

Reported-by: Guenter Roeck 
Signed-off-by: Peter Zijlstra (Intel) 
Cc: Linus Torvalds 
Cc: Nigel Topham 
Cc: Noam Camus 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: Vineet Gupta 
Cc: linux-kernel@vger.kernel.org
Cc: linux-snps-arc@lists.infradead.org
Signed-off-by: Ingo Molnar

locking/atomic: Remove linux/atomic.h:atomic_fetch_or()

2016-06-16T08:48:32+00:00

Since all architectures have this implemented now natively, remove this
dead code.

Signed-off-by: Peter Zijlstra (Intel) 
Cc: Andrew Morton 
Cc: Linus Torvalds 
Cc: Paul E. McKenney 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: linux-arch@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar

locking/atomic, arch/arc: Implement atomic_fetch_{add,sub,and,andnot,or,xor}()

2016-06-16T08:48:20+00:00

Implement FETCH-OP atomic primitives, these are very similar to the
existing OP-RETURN primitives we already have, except they return the
value of the atomic variable _before_ modification.

This is especially useful for irreversible operations -- such as
bitops (because it becomes impossible to reconstruct the state prior
to modification).

Signed-off-by: Peter Zijlstra (Intel) 
Acked-by: Vineet Gupta 
Cc: Andrew Morton 
Cc: Linus Torvalds 
Cc: Noam Camus 
Cc: Paul E. McKenney 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: linux-arch@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-snps-arc@lists.infradead.org
Signed-off-by: Ingo Molnar

Revert "ARCv2: spinlock/rwlock/atomics: Delayed retry of failed SCOND with exponential backoff"

2016-06-02T05:29:23+00:00

This reverts commit e78fdfef84be13a5c2b8276e12203cdf24778596.

The issue was fixed in hardware in HS2.1C release and there are no known
external users of affected RTL so revert the whole delayed retry series !

Signed-off-by: Vineet Gupta

Revert "ARCv2: spinlock/rwlock/atomics: reduce 1 instruction in exponential backoff"

2016-06-02T05:29:22+00:00

This reverts commit 10971638701dedadb58c88ce4d31c9375b224ed6.

The issue was fixed in hardware in HS2.1C release and there are no known
external users of affected RTL - so revert thw whole delayed retry
series !

Signed-off-by: Vineet Gupta

ARC: [plat-eznps] Use dedicated atomic/bitops/cmpxchg

2016-05-09T04:02:33+00:00

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