kernel-ark/arch/sparc/lib/atomic_64.S
David S. Miller 193d2aadc0 sparc: Support atomic64_dec_if_positive properly.
Sparc32 already supported it, as a consequence of using the
generic atomic64 implementation.  And the sparc64 implementation
is rather trivial.

This allows us to set ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE for all
of sparc, and avoid the annoying warning from lib/atomic64_test.c

Signed-off-by: David S. Miller <davem@davemloft.net>
2012-11-09 19:37:59 -08:00

134 lines
2.8 KiB
ArmAsm

/* atomic.S: These things are too big to do inline.
*
* Copyright (C) 1999, 2007 2012 David S. Miller (davem@davemloft.net)
*/
#include <linux/linkage.h>
#include <asm/asi.h>
#include <asm/backoff.h>
.text
/* Two versions of the atomic routines, one that
* does not return a value and does not perform
* memory barriers, and a second which returns
* a value and does the barriers.
*/
ENTRY(atomic_add) /* %o0 = increment, %o1 = atomic_ptr */
BACKOFF_SETUP(%o2)
1: lduw [%o1], %g1
add %g1, %o0, %g7
cas [%o1], %g1, %g7
cmp %g1, %g7
bne,pn %icc, BACKOFF_LABEL(2f, 1b)
nop
retl
nop
2: BACKOFF_SPIN(%o2, %o3, 1b)
ENDPROC(atomic_add)
ENTRY(atomic_sub) /* %o0 = decrement, %o1 = atomic_ptr */
BACKOFF_SETUP(%o2)
1: lduw [%o1], %g1
sub %g1, %o0, %g7
cas [%o1], %g1, %g7
cmp %g1, %g7
bne,pn %icc, BACKOFF_LABEL(2f, 1b)
nop
retl
nop
2: BACKOFF_SPIN(%o2, %o3, 1b)
ENDPROC(atomic_sub)
ENTRY(atomic_add_ret) /* %o0 = increment, %o1 = atomic_ptr */
BACKOFF_SETUP(%o2)
1: lduw [%o1], %g1
add %g1, %o0, %g7
cas [%o1], %g1, %g7
cmp %g1, %g7
bne,pn %icc, BACKOFF_LABEL(2f, 1b)
add %g1, %o0, %g1
retl
sra %g1, 0, %o0
2: BACKOFF_SPIN(%o2, %o3, 1b)
ENDPROC(atomic_add_ret)
ENTRY(atomic_sub_ret) /* %o0 = decrement, %o1 = atomic_ptr */
BACKOFF_SETUP(%o2)
1: lduw [%o1], %g1
sub %g1, %o0, %g7
cas [%o1], %g1, %g7
cmp %g1, %g7
bne,pn %icc, BACKOFF_LABEL(2f, 1b)
sub %g1, %o0, %g1
retl
sra %g1, 0, %o0
2: BACKOFF_SPIN(%o2, %o3, 1b)
ENDPROC(atomic_sub_ret)
ENTRY(atomic64_add) /* %o0 = increment, %o1 = atomic_ptr */
BACKOFF_SETUP(%o2)
1: ldx [%o1], %g1
add %g1, %o0, %g7
casx [%o1], %g1, %g7
cmp %g1, %g7
bne,pn %xcc, BACKOFF_LABEL(2f, 1b)
nop
retl
nop
2: BACKOFF_SPIN(%o2, %o3, 1b)
ENDPROC(atomic64_add)
ENTRY(atomic64_sub) /* %o0 = decrement, %o1 = atomic_ptr */
BACKOFF_SETUP(%o2)
1: ldx [%o1], %g1
sub %g1, %o0, %g7
casx [%o1], %g1, %g7
cmp %g1, %g7
bne,pn %xcc, BACKOFF_LABEL(2f, 1b)
nop
retl
nop
2: BACKOFF_SPIN(%o2, %o3, 1b)
ENDPROC(atomic64_sub)
ENTRY(atomic64_add_ret) /* %o0 = increment, %o1 = atomic_ptr */
BACKOFF_SETUP(%o2)
1: ldx [%o1], %g1
add %g1, %o0, %g7
casx [%o1], %g1, %g7
cmp %g1, %g7
bne,pn %xcc, BACKOFF_LABEL(2f, 1b)
nop
retl
add %g1, %o0, %o0
2: BACKOFF_SPIN(%o2, %o3, 1b)
ENDPROC(atomic64_add_ret)
ENTRY(atomic64_sub_ret) /* %o0 = decrement, %o1 = atomic_ptr */
BACKOFF_SETUP(%o2)
1: ldx [%o1], %g1
sub %g1, %o0, %g7
casx [%o1], %g1, %g7
cmp %g1, %g7
bne,pn %xcc, BACKOFF_LABEL(2f, 1b)
nop
retl
sub %g1, %o0, %o0
2: BACKOFF_SPIN(%o2, %o3, 1b)
ENDPROC(atomic64_sub_ret)
ENTRY(atomic64_dec_if_positive) /* %o0 = atomic_ptr */
BACKOFF_SETUP(%o2)
1: ldx [%o0], %g1
brlez,pn %g1, 3f
sub %g1, 1, %g7
casx [%o0], %g1, %g7
cmp %g1, %g7
bne,pn %xcc, BACKOFF_LABEL(2f, 1b)
nop
3: retl
sub %g1, 1, %o0
2: BACKOFF_SPIN(%o2, %o3, 1b)
ENDPROC(atomic64_dec_if_positive)