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authorDavid S. Miller <davem@davemloft.net>2010-08-18 22:53:26 -0700
committerDavid S. Miller <davem@davemloft.net>2010-08-18 22:53:26 -0700
commit0f58189d4a3ca96d7959501ecb203177efdbc5bd (patch)
treeb5ad2f63da4c1caa5d20487cf370d51e4392111c /arch/sparc
parent6ec274750c99448c3412bbc10c97ce0c993f8a4e (diff)
sparc64: Make lock backoff really a NOP on UP builds.
As noticed by Mikulas Patocka, the backoff macros don't completely nop out for UP builds, we still get a branch always and a delay slot nop. Fix this by making the branch to the backoff spin loop selective, then we can nop out the spin loop completely. Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'arch/sparc')
-rw-r--r--arch/sparc/include/asm/backoff.h11
-rw-r--r--arch/sparc/lib/atomic_64.S16
-rw-r--r--arch/sparc/lib/bitops.S12
3 files changed, 22 insertions, 17 deletions
diff --git a/arch/sparc/include/asm/backoff.h b/arch/sparc/include/asm/backoff.h
index fa1fdf67e350..db3af0d30fb1 100644
--- a/arch/sparc/include/asm/backoff.h
+++ b/arch/sparc/include/asm/backoff.h
@@ -8,6 +8,9 @@
#define BACKOFF_SETUP(reg) \
mov 1, reg
+#define BACKOFF_LABEL(spin_label, continue_label) \
+ spin_label
+
#define BACKOFF_SPIN(reg, tmp, label) \
mov reg, tmp; \
88: brnz,pt tmp, 88b; \
@@ -22,9 +25,11 @@
#else
#define BACKOFF_SETUP(reg)
-#define BACKOFF_SPIN(reg, tmp, label) \
- ba,pt %xcc, label; \
- nop;
+
+#define BACKOFF_LABEL(spin_label, continue_label) \
+ continue_label
+
+#define BACKOFF_SPIN(reg, tmp, label)
#endif
diff --git a/arch/sparc/lib/atomic_64.S b/arch/sparc/lib/atomic_64.S
index 703c9c3935b7..59186e0fcf39 100644
--- a/arch/sparc/lib/atomic_64.S
+++ b/arch/sparc/lib/atomic_64.S
@@ -21,7 +21,7 @@ atomic_add: /* %o0 = increment, %o1 = atomic_ptr */
add %g1, %o0, %g7
cas [%o1], %g1, %g7
cmp %g1, %g7
- bne,pn %icc, 2f
+ bne,pn %icc, BACKOFF_LABEL(2f, 1b)
nop
retl
nop
@@ -36,7 +36,7 @@ atomic_sub: /* %o0 = decrement, %o1 = atomic_ptr */
sub %g1, %o0, %g7
cas [%o1], %g1, %g7
cmp %g1, %g7
- bne,pn %icc, 2f
+ bne,pn %icc, BACKOFF_LABEL(2f, 1b)
nop
retl
nop
@@ -51,7 +51,7 @@ atomic_add_ret: /* %o0 = increment, %o1 = atomic_ptr */
add %g1, %o0, %g7
cas [%o1], %g1, %g7
cmp %g1, %g7
- bne,pn %icc, 2f
+ bne,pn %icc, BACKOFF_LABEL(2f, 1b)
add %g1, %o0, %g1
retl
sra %g1, 0, %o0
@@ -66,7 +66,7 @@ atomic_sub_ret: /* %o0 = decrement, %o1 = atomic_ptr */
sub %g1, %o0, %g7
cas [%o1], %g1, %g7
cmp %g1, %g7
- bne,pn %icc, 2f
+ bne,pn %icc, BACKOFF_LABEL(2f, 1b)
sub %g1, %o0, %g1
retl
sra %g1, 0, %o0
@@ -81,7 +81,7 @@ atomic64_add: /* %o0 = increment, %o1 = atomic_ptr */
add %g1, %o0, %g7
casx [%o1], %g1, %g7
cmp %g1, %g7
- bne,pn %xcc, 2f
+ bne,pn %xcc, BACKOFF_LABEL(2f, 1b)
nop
retl
nop
@@ -96,7 +96,7 @@ atomic64_sub: /* %o0 = decrement, %o1 = atomic_ptr */
sub %g1, %o0, %g7
casx [%o1], %g1, %g7
cmp %g1, %g7
- bne,pn %xcc, 2f
+ bne,pn %xcc, BACKOFF_LABEL(2f, 1b)
nop
retl
nop
@@ -111,7 +111,7 @@ atomic64_add_ret: /* %o0 = increment, %o1 = atomic_ptr */
add %g1, %o0, %g7
casx [%o1], %g1, %g7
cmp %g1, %g7
- bne,pn %xcc, 2f
+ bne,pn %xcc, BACKOFF_LABEL(2f, 1b)
nop
retl
add %g1, %o0, %o0
@@ -126,7 +126,7 @@ atomic64_sub_ret: /* %o0 = decrement, %o1 = atomic_ptr */
sub %g1, %o0, %g7
casx [%o1], %g1, %g7
cmp %g1, %g7
- bne,pn %xcc, 2f
+ bne,pn %xcc, BACKOFF_LABEL(2f, 1b)
nop
retl
sub %g1, %o0, %o0
diff --git a/arch/sparc/lib/bitops.S b/arch/sparc/lib/bitops.S
index 2b7228cb8c22..3dc61d5537c0 100644
--- a/arch/sparc/lib/bitops.S
+++ b/arch/sparc/lib/bitops.S
@@ -22,7 +22,7 @@ test_and_set_bit: /* %o0=nr, %o1=addr */
or %g7, %o2, %g1
casx [%o1], %g7, %g1
cmp %g7, %g1
- bne,pn %xcc, 2f
+ bne,pn %xcc, BACKOFF_LABEL(2f, 1b)
and %g7, %o2, %g2
clr %o0
movrne %g2, 1, %o0
@@ -45,7 +45,7 @@ test_and_clear_bit: /* %o0=nr, %o1=addr */
andn %g7, %o2, %g1
casx [%o1], %g7, %g1
cmp %g7, %g1
- bne,pn %xcc, 2f
+ bne,pn %xcc, BACKOFF_LABEL(2f, 1b)
and %g7, %o2, %g2
clr %o0
movrne %g2, 1, %o0
@@ -68,7 +68,7 @@ test_and_change_bit: /* %o0=nr, %o1=addr */
xor %g7, %o2, %g1
casx [%o1], %g7, %g1
cmp %g7, %g1
- bne,pn %xcc, 2f
+ bne,pn %xcc, BACKOFF_LABEL(2f, 1b)
and %g7, %o2, %g2
clr %o0
movrne %g2, 1, %o0
@@ -91,7 +91,7 @@ set_bit: /* %o0=nr, %o1=addr */
or %g7, %o2, %g1
casx [%o1], %g7, %g1
cmp %g7, %g1
- bne,pn %xcc, 2f
+ bne,pn %xcc, BACKOFF_LABEL(2f, 1b)
nop
retl
nop
@@ -112,7 +112,7 @@ clear_bit: /* %o0=nr, %o1=addr */
andn %g7, %o2, %g1
casx [%o1], %g7, %g1
cmp %g7, %g1
- bne,pn %xcc, 2f
+ bne,pn %xcc, BACKOFF_LABEL(2f, 1b)
nop
retl
nop
@@ -133,7 +133,7 @@ change_bit: /* %o0=nr, %o1=addr */
xor %g7, %o2, %g1
casx [%o1], %g7, %g1
cmp %g7, %g1
- bne,pn %xcc, 2f
+ bne,pn %xcc, BACKOFF_LABEL(2f, 1b)
nop
retl
nop