lk/linux-kernel-test
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

sparc64: Make lock backoff really a NOP on UP builds.

Browse Source 
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>
This commit is contained in:
David S. Miller
2010-08-18 22:53:26 -07:00
parent 6ec274750c
commit 0f58189d4a
3 changed files with 22 additions and 17 deletions
Download Patch File Download Diff File Expand all files Collapse all files

12
arch/sparc/lib/bitops.S
View File

@@ -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