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| author | David S. Miller <davem@davemloft.net> | 2012-11-09 19:37:59 -0800 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2012-11-09 19:37:59 -0800 |
| commit | 193d2aadc0ff5c687f6f0d5ef1d38c86ab511a14 (patch) | |
| tree | 294286e259a08c977e3e71819b2c1d763b13312f /arch | |
| parent | 0bce04be442cf4d6e4ba9dac2f0a4c5ee88af5c5 (diff) | |
| download | lwn-193d2aadc0ff5c687f6f0d5ef1d38c86ab511a14.tar.gz lwn-193d2aadc0ff5c687f6f0d5ef1d38c86ab511a14.zip | |
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>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/sparc/Kconfig | 1 | ||||
| -rw-r--r-- | arch/sparc/include/asm/atomic_64.h | 4 | ||||
| -rw-r--r-- | arch/sparc/lib/atomic_64.S | 16 | ||||
| -rw-r--r-- | arch/sparc/lib/ksyms.c | 1 |
4 files changed, 20 insertions, 2 deletions
diff --git a/arch/sparc/Kconfig b/arch/sparc/Kconfig index b6b442b0d793..9f2edb5c5551 100644 --- a/arch/sparc/Kconfig +++ b/arch/sparc/Kconfig @@ -20,6 +20,7 @@ config SPARC select HAVE_ARCH_TRACEHOOK select SYSCTL_EXCEPTION_TRACE select ARCH_WANT_OPTIONAL_GPIOLIB + select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE select RTC_CLASS select RTC_DRV_M48T59 select HAVE_IRQ_WORK diff --git a/arch/sparc/include/asm/atomic_64.h b/arch/sparc/include/asm/atomic_64.h index ce35a1cf1a20..be56a244c9cf 100644 --- a/arch/sparc/include/asm/atomic_64.h +++ b/arch/sparc/include/asm/atomic_64.h @@ -1,7 +1,7 @@ /* atomic.h: Thankfully the V9 is at least reasonable for this * stuff. * - * Copyright (C) 1996, 1997, 2000 David S. Miller (davem@redhat.com) + * Copyright (C) 1996, 1997, 2000, 2012 David S. Miller (davem@redhat.com) */ #ifndef __ARCH_SPARC64_ATOMIC__ @@ -106,6 +106,8 @@ static inline long atomic64_add_unless(atomic64_t *v, long a, long u) #define atomic64_inc_not_zero(v) atomic64_add_unless((v), 1, 0) +extern long atomic64_dec_if_positive(atomic64_t *v); + /* Atomic operations are already serializing */ #define smp_mb__before_atomic_dec() barrier() #define smp_mb__after_atomic_dec() barrier() diff --git a/arch/sparc/lib/atomic_64.S b/arch/sparc/lib/atomic_64.S index 4d502da3de78..85c233d0a340 100644 --- a/arch/sparc/lib/atomic_64.S +++ b/arch/sparc/lib/atomic_64.S @@ -1,6 +1,6 @@ /* atomic.S: These things are too big to do inline. * - * Copyright (C) 1999, 2007 David S. Miller (davem@davemloft.net) + * Copyright (C) 1999, 2007 2012 David S. Miller (davem@davemloft.net) */ #include <linux/linkage.h> @@ -117,3 +117,17 @@ ENTRY(atomic64_sub_ret) /* %o0 = decrement, %o1 = atomic_ptr */ 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) diff --git a/arch/sparc/lib/ksyms.c b/arch/sparc/lib/ksyms.c index ee31b884c61b..0c4e35e522fa 100644 --- a/arch/sparc/lib/ksyms.c +++ b/arch/sparc/lib/ksyms.c @@ -116,6 +116,7 @@ EXPORT_SYMBOL(atomic64_add); EXPORT_SYMBOL(atomic64_add_ret); EXPORT_SYMBOL(atomic64_sub); EXPORT_SYMBOL(atomic64_sub_ret); +EXPORT_SYMBOL(atomic64_dec_if_positive); /* Atomic bit operations. */ EXPORT_SYMBOL(test_and_set_bit); |