diff --git a/arch/sparc/kernel/sparc_ksyms.c b/arch/sparc/kernel/sparc_ksyms.c
index 4d441a5..33dadd9 100644
--- a/arch/sparc/kernel/sparc_ksyms.c
+++ b/arch/sparc/kernel/sparc_ksyms.c
@@ -87,6 +87,7 @@
 extern void ___clear_bit(void);
 extern void ___change_bit(void);
 extern void ___rw_read_enter(void);
+extern void ___rw_read_try(void);
 extern void ___rw_read_exit(void);
 extern void ___rw_write_enter(void);
 
@@ -104,8 +105,9 @@
 EXPORT_SYMBOL(sparc_cpu_model);
 EXPORT_SYMBOL(kernel_thread);
 #ifdef CONFIG_SMP
-// XXX find what uses (or used) these.
+// XXX find what uses (or used) these.   AV: see asm/spinlock.h
 EXPORT_SYMBOL(___rw_read_enter);
+EXPORT_SYMBOL(___rw_read_try);
 EXPORT_SYMBOL(___rw_read_exit);
 EXPORT_SYMBOL(___rw_write_enter);
 #endif
diff --git a/arch/sparc/lib/locks.S b/arch/sparc/lib/locks.S
index 95fa484..b1df55c 100644
--- a/arch/sparc/lib/locks.S
+++ b/arch/sparc/lib/locks.S
@@ -25,6 +25,15 @@
 	 ldstub	[%g1 + 3], %g2
 	b	___rw_read_enter_spin_on_wlock
 	 ldub	[%g1 + 3], %g2
+___rw_read_try_spin_on_wlock:
+	andcc	%g2, 0xff, %g0
+	be,a	___rw_read_try
+	 ldstub	[%g1 + 3], %g2
+	xnorcc	%g2, 0x0, %o0	/* if g2 is ~0, set o0 to 0 and bugger off */
+	bne,a	___rw_read_enter_spin_on_wlock
+	 ld	[%g1], %g2
+	retl
+	 mov	%g4, %o7
 ___rw_read_exit_spin_on_wlock:
 	orcc	%g2, 0x0, %g0
 	be,a	___rw_read_exit
@@ -60,6 +69,17 @@
 	retl
 	 mov	%g4, %o7
 
+	.globl	___rw_read_try
+___rw_read_try:
+	orcc	%g2, 0x0, %g0
+	bne	___rw_read_try_spin_on_wlock
+	 ld	[%g1], %g2
+	add	%g2, 1, %g2
+	st	%g2, [%g1]
+	set	1, %o1
+	retl
+	 mov	%g4, %o7
+
 	.globl	___rw_write_enter
 ___rw_write_enter:
 	orcc	%g2, 0x0, %g0