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authorPeter Zijlstra <peterz@infradead.org>2016-04-18 01:16:08 +0200
committerIngo Molnar <mingo@kernel.org>2016-06-16 10:48:23 +0200
commite87fc0ec070554e34812be68267a9450271868d6 (patch)
treed99ccf1052722bd4e699414851673768f4004e8f /arch/blackfin/mach-bf561
parent1a6eafacd4811cdc1b138faee858527658eee4e1 (diff)
downloadlinux-e87fc0ec070554e34812be68267a9450271868d6.tar.bz2
locking/atomic, arch/blackfin: Implement atomic_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> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Miao <realmz6@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: adi-buildroot-devel@lists.sourceforge.net Cc: linux-arch@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/blackfin/mach-bf561')
-rw-r--r--arch/blackfin/mach-bf561/atomic.S43
1 files changed, 31 insertions, 12 deletions
diff --git a/arch/blackfin/mach-bf561/atomic.S b/arch/blackfin/mach-bf561/atomic.S
index 26fccb5568b9..1e2989c5d6b2 100644
--- a/arch/blackfin/mach-bf561/atomic.S
+++ b/arch/blackfin/mach-bf561/atomic.S
@@ -607,6 +607,28 @@ ENDPROC(___raw_atomic_add_asm)
/*
* r0 = ptr
+ * r1 = value
+ *
+ * ADD a signed value to a 32bit word and return the old value atomically.
+ * Clobbers: r3:0, p1:0
+ */
+ENTRY(___raw_atomic_xadd_asm)
+ p1 = r0;
+ r3 = r1;
+ [--sp] = rets;
+ call _get_core_lock;
+ r3 = [p1];
+ r2 = r3 + r2;
+ [p1] = r2;
+ r1 = p1;
+ call _put_core_lock;
+ r0 = r3;
+ rets = [sp++];
+ rts;
+ENDPROC(___raw_atomic_add_asm)
+
+/*
+ * r0 = ptr
* r1 = mask
*
* AND the mask bits from a 32bit word and return the old 32bit value
@@ -618,10 +640,9 @@ ENTRY(___raw_atomic_and_asm)
r3 = r1;
[--sp] = rets;
call _get_core_lock;
- r2 = [p1];
- r3 = r2 & r3;
- [p1] = r3;
- r3 = r2;
+ r3 = [p1];
+ r2 = r2 & r3;
+ [p1] = r2;
r1 = p1;
call _put_core_lock;
r0 = r3;
@@ -642,10 +663,9 @@ ENTRY(___raw_atomic_or_asm)
r3 = r1;
[--sp] = rets;
call _get_core_lock;
- r2 = [p1];
- r3 = r2 | r3;
- [p1] = r3;
- r3 = r2;
+ r3 = [p1];
+ r2 = r2 | r3;
+ [p1] = r2;
r1 = p1;
call _put_core_lock;
r0 = r3;
@@ -666,10 +686,9 @@ ENTRY(___raw_atomic_xor_asm)
r3 = r1;
[--sp] = rets;
call _get_core_lock;
- r2 = [p1];
- r3 = r2 ^ r3;
- [p1] = r3;
- r3 = r2;
+ r3 = [p1];
+ r2 = r2 ^ r3;
+ [p1] = r2;
r1 = p1;
call _put_core_lock;
r0 = r3;