Use "m" constraint instead of "r" for the address, as "m" allows
compiler to access adjacent locations using base + offset, while "r"
requires updating the base register every time.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>

Numeric assembly arguments are hard to understand and assembly code that
uses them is hard to modify. Use named arguments in BIT_OP and
TEST_AND_BIT_OP macros.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>

Parameterize macros with function name, opcode and inversion pattern.
This reduces code duplication removing 2/3 of definitions.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>

change_bit implementation for XCHAL_HAVE_EXCLUSIVE case changes all bits
except the one required due to copy-paste error from clear_bit.

Cc: stable@vger.kernel.org # v5.2+
Fixes: f7c34874f04a ("xtensa: add exclusive atomics support")
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>

Implement atomic primitives using exclusive access opcodes available in
the recent xtensa cores.
Since l32ex/s32ex don't have any memory ordering guarantees don't define
__smp_mb__before_atomic/__smp_mb__after_atomic to make them use memw.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>

These headers are not exported to userspace, so they're never used
without __KERNEL__ defined. Drop these ifdef statements.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>

Make __ffs result type unsigned long to match generic asm
implementation. This fixes the following build warning:

  mm/nobootmem.c: In function '__free_pages_memory':
  include/linux/kernel.h:742:17: warning: comparison of distinct pointer
                                          types lacks a cast
    (void) (&_min1 == &_min2);  \
  		 ^
  mm/nobootmem.c:100:11: note: in expansion of macro 'min'
     order = min(MAX_ORDER - 1UL, __ffs(start));

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>

Xtensa SMP has compare-and-swap which is fully serializing, therefore
its exising smp_mb__{before,after}_clear_bit() appear unduly heavy.

Implement the new barriers as barrier().

Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/n/tip-e9rqjxr1m1ejsob9p433kmji@git.kernel.org
Cc: Chris Zankel <chris@zankel.net>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: linux-kernel@vger.kernel.org
Cc: linux-xtensa@linux-xtensa.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

This is largely based on SMP code from the xtensa-2.6.29-smp tree by
Piet Delaney, Marc Gauthier, Joe Taylor, Christian Zankel (and possibly
other Tensilica folks).

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: Chris Zankel <chris@zankel.net>

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: Chris Zankel <chris@zankel.net>