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authorDavid S. Miller <davem@davemloft.net>2005-09-14 21:47:01 -0700
committerDavid S. Miller <davem@davemloft.net>2005-09-14 21:47:01 -0700
commit4db2ce0199f04b6e99999f22e28ef9a0ae5f0d2f (patch)
tree87a00c97e02a77cdfec517398caa3f1d8f6a2f0d /arch/sparc64/lib
parent4a805e863d6b9466baf7084e1d6fdbe6e0628d8e (diff)
[LIB]: Consolidate _atomic_dec_and_lock()
Several implementations were essentialy a common piece of C code using the cmpxchg() macro. Put the implementation in one spot that everyone can share, and convert sparc64 over to using this. Alpha is the lone arch-specific implementation, which codes up a special fast path for the common case in order to avoid GP reloading which a pure C version would require. Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'arch/sparc64/lib')
-rw-r--r--arch/sparc64/lib/Makefile2
-rw-r--r--arch/sparc64/lib/dec_and_lock.S80
2 files changed, 0 insertions, 82 deletions
diff --git a/arch/sparc64/lib/Makefile b/arch/sparc64/lib/Makefile
index d968aebe83b..c295806500f 100644
--- a/arch/sparc64/lib/Makefile
+++ b/arch/sparc64/lib/Makefile
@@ -14,6 +14,4 @@ lib-y := PeeCeeI.o copy_page.o clear_page.o strlen.o strncmp.o \
copy_in_user.o user_fixup.o memmove.o \
mcount.o ipcsum.o rwsem.o xor.o find_bit.o delay.o
-lib-$(CONFIG_HAVE_DEC_LOCK) += dec_and_lock.o
-
obj-y += iomap.o
diff --git a/arch/sparc64/lib/dec_and_lock.S b/arch/sparc64/lib/dec_and_lock.S
deleted file mode 100644
index 8ee288dd0af..00000000000
--- a/arch/sparc64/lib/dec_and_lock.S
+++ /dev/null
@@ -1,80 +0,0 @@
-/* $Id: dec_and_lock.S,v 1.5 2001/11/18 00:12:56 davem Exp $
- * dec_and_lock.S: Sparc64 version of "atomic_dec_and_lock()"
- * using cas and ldstub instructions.
- *
- * Copyright (C) 2000 David S. Miller (davem@redhat.com)
- */
-#include <linux/config.h>
-#include <asm/thread_info.h>
-
- .text
- .align 64
-
- /* CAS basically works like this:
- *
- * void CAS(MEM, REG1, REG2)
- * {
- * START_ATOMIC();
- * if (*(MEM) == REG1) {
- * TMP = *(MEM);
- * *(MEM) = REG2;
- * REG2 = TMP;
- * } else
- * REG2 = *(MEM);
- * END_ATOMIC();
- * }
- */
-
- .globl _atomic_dec_and_lock
-_atomic_dec_and_lock: /* %o0 = counter, %o1 = lock */
-loop1: lduw [%o0], %g2
- subcc %g2, 1, %g7
- be,pn %icc, start_to_zero
- nop
-nzero: cas [%o0], %g2, %g7
- cmp %g2, %g7
- bne,pn %icc, loop1
- mov 0, %g1
-
-out:
- membar #StoreLoad | #StoreStore
- retl
- mov %g1, %o0
-start_to_zero:
-#ifdef CONFIG_PREEMPT
- ldsw [%g6 + TI_PRE_COUNT], %g3
- add %g3, 1, %g3
- stw %g3, [%g6 + TI_PRE_COUNT]
-#endif
-to_zero:
- ldstub [%o1], %g3
- membar #StoreLoad | #StoreStore
- brnz,pn %g3, spin_on_lock
- nop
-loop2: cas [%o0], %g2, %g7 /* ASSERT(g7 == 0) */
- cmp %g2, %g7
-
- be,pt %icc, out
- mov 1, %g1
- lduw [%o0], %g2
- subcc %g2, 1, %g7
- be,pn %icc, loop2
- nop
- membar #StoreStore | #LoadStore
- stb %g0, [%o1]
-#ifdef CONFIG_PREEMPT
- ldsw [%g6 + TI_PRE_COUNT], %g3
- sub %g3, 1, %g3
- stw %g3, [%g6 + TI_PRE_COUNT]
-#endif
-
- b,pt %xcc, nzero
- nop
-spin_on_lock:
- ldub [%o1], %g3
- membar #LoadLoad
- brnz,pt %g3, spin_on_lock
- nop
- ba,pt %xcc, to_zero
- nop
- nop