Allow threading libraries to register their own locking

implementation in case default one provided by rtld is
not suitable.

Consolidate various identical MD lock implementation into
a single file using appropriate machine/atomic.h.

Approved by:	re (scottl)

2 files changed, 12 insertions, 55 deletions

diff --git a/libexec/rtld-elf/alpha/rtld_machdep.h b/libexec/rtld-elf/alpha/rtld_machdep.h
index d224b9c..008abce 100644
--- a/libexec/rtld-elf/alpha/rtld_machdep.h
+++ b/libexec/rtld-elf/alpha/rtld_machdep.h
@@ -29,6 +29,18 @@
 #ifndef RTLD_MACHDEP_H
 #define RTLD_MACHDEP_H	1
 
+#include <sys/types.h>
+#include <machine/atomic.h>
+
+/*
+ * This value of CACHE_LINE_SIZE is conservative.  The actual size
+ * is 32 on the  21064, 21064A, 21066, 21066A, and 21164.  It is 64
+ * on the 21264.  Compaq recommends sequestering each lock in its own
+ * 128-byte block to allow for future implementations with larger
+ * cache lines.
+ */
+#define CACHE_LINE_SIZE		128
+
 struct Struct_Obj_Entry;
 
 /* Return the address of the .dynamic section in the dynamic linker. */
@@ -48,10 +60,4 @@ Elf_Addr reloc_jmpslot(Elf_Addr *, Elf_Addr,
 /* Lazy binding entry point, called via PLT. */
 void _rtld_bind_start_old(void);
 
-/* Atomic operations. */
-int cmp0_and_store_int(volatile int *, int);
-void atomic_add_int(volatile int *, int);
-void atomic_incr_int(volatile int *);
-void atomic_decr_int(volatile int *);
-
 #endif
diff --git a/libexec/rtld-elf/alpha/rtld_start.S b/libexec/rtld-elf/alpha/rtld_start.S
index d21c088..8ab7605 100644
--- a/libexec/rtld-elf/alpha/rtld_start.S
+++ b/libexec/rtld-elf/alpha/rtld_start.S
@@ -209,52 +209,3 @@ NESTED_NOPROFILE(_rtld_bind_start_old, 0, 168, ra, 0, 0)
 
 END(_rtld_bind_start_old)
 
-/*
- * int cmp0_and_store_int(volatile int *p, int newval);
- *
- * If an int holds 0, store newval into it; else do nothing.  Returns
- * the previous value.
- */
-LEAF(cmp0_and_store_int, 2)
-1:	mov	a1, t0
-	ldl_l	v0, 0(a0)
-	bne	v0, 3f
-	stl_c	t0, 0(a0)
-	beq	t0, 2f
-	mb
-	RET
-2:	br	1b
-3:	RET
-END(cmp0_and_store_int)
-
-LEAF(atomic_add_int, 2)
-0:	ldl_l	t0, 0(a0)
-	addq	t0, a1, t0
-	stl_c	t0, 0(a0)
-	beq	t0, 1f
-	mb
-	RET
-1:	br	0b
-END(atomic_add_int)
- 
-/* Atomically increment an int. */
-LEAF(atomic_incr_int, 1)
-0:	ldl_l	t0, 0(a0)
-	addq	t0, 1, t0
-	stl_c	t0, 0(a0)
-	beq	t0, 1f
-	mb
-	RET
-1:	br	0b
-END(atomic_incr_int)
-
-/* Atomically decrement an int. */
-LEAF(atomic_decr_int, 1)
-0:	ldl_l	t0, 0(a0)
-	subq	t0, 1, t0
-	stl_c	t0, 0(a0)
-	beq	t0, 1f
-	mb
-	RET
-1:	br	0b
-END(atomic_decr_int)