diff options
| author | Peter Zijlstra <peterz@infradead.org> | 2016-04-18 01:16:04 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2016-06-16 10:48:30 +0200 |
| commit | 3a1adb23a52c920304239efff377d3bc967febc2 (patch) | |
| tree | 63383d193b7a7adaec40939daac2cdd22326108a /arch/sparc/lib/atomic_64.S | |
| parent | 7d9794e7523798e1b9422ad9f4e4d808ae5d5932 (diff) | |
locking/atomic, arch/sparc: Implement atomic{,64}_fetch_{add,sub,and,or,xor}()
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) <peterz@infradead.org>
Acked-by: David S. Miller <davem@davemloft.net>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: James Y Knight <jyknight@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-arch@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: sparclinux@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/sparc/lib/atomic_64.S')
| -rw-r--r-- | arch/sparc/lib/atomic_64.S | 61 |
1 files changed, 50 insertions, 11 deletions
diff --git a/arch/sparc/lib/atomic_64.S b/arch/sparc/lib/atomic_64.S index d6b0363f345b..a5c5a0279ccc 100644 --- a/arch/sparc/lib/atomic_64.S +++ b/arch/sparc/lib/atomic_64.S @@ -9,10 +9,11 @@ .text - /* Two versions of the atomic routines, one that + /* Three 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. + * memory barriers, and a two which return + * a value, the new and old value resp. and does the + * barriers. */ #define ATOMIC_OP(op) \ @@ -43,15 +44,34 @@ ENTRY(atomic_##op##_return) /* %o0 = increment, %o1 = atomic_ptr */ \ 2: BACKOFF_SPIN(%o2, %o3, 1b); \ ENDPROC(atomic_##op##_return); -#define ATOMIC_OPS(op) ATOMIC_OP(op) ATOMIC_OP_RETURN(op) +#define ATOMIC_FETCH_OP(op) \ +ENTRY(atomic_fetch_##op) /* %o0 = increment, %o1 = atomic_ptr */ \ + BACKOFF_SETUP(%o2); \ +1: lduw [%o1], %g1; \ + op %g1, %o0, %g7; \ + cas [%o1], %g1, %g7; \ + cmp %g1, %g7; \ + bne,pn %icc, BACKOFF_LABEL(2f, 1b); \ + nop; \ + retl; \ + sra %g1, 0, %o0; \ +2: BACKOFF_SPIN(%o2, %o3, 1b); \ +ENDPROC(atomic_fetch_##op); + +#define ATOMIC_OPS(op) ATOMIC_OP(op) ATOMIC_OP_RETURN(op) ATOMIC_FETCH_OP(op) ATOMIC_OPS(add) ATOMIC_OPS(sub) -ATOMIC_OP(and) -ATOMIC_OP(or) -ATOMIC_OP(xor) #undef ATOMIC_OPS +#define ATOMIC_OPS(op) ATOMIC_OP(op) ATOMIC_FETCH_OP(op) + +ATOMIC_OPS(and) +ATOMIC_OPS(or) +ATOMIC_OPS(xor) + +#undef ATOMIC_OPS +#undef ATOMIC_FETCH_OP #undef ATOMIC_OP_RETURN #undef ATOMIC_OP @@ -83,15 +103,34 @@ ENTRY(atomic64_##op##_return) /* %o0 = increment, %o1 = atomic_ptr */ \ 2: BACKOFF_SPIN(%o2, %o3, 1b); \ ENDPROC(atomic64_##op##_return); -#define ATOMIC64_OPS(op) ATOMIC64_OP(op) ATOMIC64_OP_RETURN(op) +#define ATOMIC64_FETCH_OP(op) \ +ENTRY(atomic64_fetch_##op) /* %o0 = increment, %o1 = atomic_ptr */ \ + BACKOFF_SETUP(%o2); \ +1: ldx [%o1], %g1; \ + op %g1, %o0, %g7; \ + casx [%o1], %g1, %g7; \ + cmp %g1, %g7; \ + bne,pn %xcc, BACKOFF_LABEL(2f, 1b); \ + nop; \ + retl; \ + mov %g1, %o0; \ +2: BACKOFF_SPIN(%o2, %o3, 1b); \ +ENDPROC(atomic64_fetch_##op); + +#define ATOMIC64_OPS(op) ATOMIC64_OP(op) ATOMIC64_OP_RETURN(op) ATOMIC64_FETCH_OP(op) ATOMIC64_OPS(add) ATOMIC64_OPS(sub) -ATOMIC64_OP(and) -ATOMIC64_OP(or) -ATOMIC64_OP(xor) #undef ATOMIC64_OPS +#define ATOMIC64_OPS(op) ATOMIC64_OP(op) ATOMIC64_FETCH_OP(op) + +ATOMIC64_OPS(and) +ATOMIC64_OPS(or) +ATOMIC64_OPS(xor) + +#undef ATOMIC64_OPS +#undef ATOMIC64_FETCH_OP #undef ATOMIC64_OP_RETURN #undef ATOMIC64_OP |