Enable %tick access for userland on sun4u systems (sun4v systems already have

this enabled).

ok pirofti@, mikeb@

3 files changed, 38 insertions, 4 deletions

diff --git a/sys/arch/sparc64/include/ctlreg.h b/sys/arch/sparc64/include/ctlreg.h
index a451e2ce00f..c1cd7411f16 100644
--- a/sys/arch/sparc64/include/ctlreg.h
+++ b/sys/arch/sparc64/include/ctlreg.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: ctlreg.h,v 1.24 2012/08/29 20:33:16 kettenis Exp $	*/
+/*	$OpenBSD: ctlreg.h,v 1.25 2012/11/07 16:31:03 kettenis Exp $	*/
 /*	$NetBSD: ctlreg.h,v 1.28 2001/08/06 23:55:34 eeh Exp $ */
 
 /*
@@ -738,6 +738,8 @@ void flush(void *p)
 #define sys_tick() (sparc_rd(sys_tick) & TICK_TICKS)
 extern u_int64_t stick(void);
 
+extern void tick_enable(void);
+
 extern void tickcmpr_set(u_int64_t);
 extern void sys_tickcmpr_set(u_int64_t);
 extern void stickcmpr_set(u_int64_t);
diff --git a/sys/arch/sparc64/sparc64/cpu.c b/sys/arch/sparc64/sparc64/cpu.c
index 29ee24bb25d..be40e9ff51e 100644
--- a/sys/arch/sparc64/sparc64/cpu.c
+++ b/sys/arch/sparc64/sparc64/cpu.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: cpu.c,v 1.57 2012/09/08 20:58:50 kettenis Exp $	*/
+/*	$OpenBSD: cpu.c,v 1.58 2012/11/07 16:31:03 kettenis Exp $	*/
 /*	$NetBSD: cpu.c,v 1.13 2001/05/26 21:27:15 chs Exp $ */
 
 /*
@@ -431,10 +431,14 @@ cpu_init(struct cpu_info *ci)
 #ifdef SUN4V
 	paddr_t pa = ci->ci_paddr;
 	int err;
+#endif
 
-	if (CPU_ISSUN4U || CPU_ISSUN4US)
+	if (CPU_ISSUN4U || CPU_ISSUN4US) {
+		tick_enable();
 		return;
+	}
 
+#ifdef SUN4V
 #define MONDO_QUEUE_SIZE	32
 #define QUEUE_ENTRY_SIZE	64
 
diff --git a/sys/arch/sparc64/sparc64/locore.s b/sys/arch/sparc64/sparc64/locore.s
index a65518e3f67..2d8531f7196 100644
--- a/sys/arch/sparc64/sparc64/locore.s
+++ b/sys/arch/sparc64/sparc64/locore.s
@@ -1,4 +1,4 @@
-/*	$OpenBSD: locore.s,v 1.167 2012/11/06 21:39:02 kettenis Exp $	*/
+/*	$OpenBSD: locore.s,v 1.168 2012/11/07 16:31:03 kettenis Exp $	*/
 /*	$NetBSD: locore.s,v 1.137 2001/08/13 06:10:10 jdolecek Exp $	*/
 
 /*
@@ -8916,6 +8916,34 @@ ENTRY(write_user_windows)
 	 nop
 
 /*
+ * Clear the Nonpriviliged Trap (NPT( bit of %tick such that it can be
+ * read from userland.  This requires us to read the current value and
+ * write it back with the bit cleared.  As a result we will lose a
+ * couple of ticks.  In order to limit the number of lost ticks, we
+ * block interrupts and make sure the instructions to read and write
+ * %tick live in the same cache line.  We tag on an extra read to work
+ * around a Blackbird (UltraSPARC-II) errata (see below).
+ */
+ENTRY(tick_enable)
+	rdpr	%pstate, %o0
+	andn	%o0, PSTATE_IE, %o1
+	wrpr	%o1, 0, %pstate		! disable interrupts
+	rdpr	%tick, %o2
+	brgez,pn %o2, 1f
+	 clr	%o1
+	mov	1, %o1
+	sllx	%o1, 63, %o1
+	ba,pt	%xcc, 1f
+	 nop
+	.align	64
+1:	rdpr	%tick, %o2
+	wrpr	%o2, %o1, %tick
+	rdpr	%tick, %g0
+
+	retl
+	 wrpr	%o0, 0, %pstate		! restore interrupts
+
+/*
  * On Blackbird (UltraSPARC-II) CPUs, writes to %tick_cmpr may fail.
  * The workaround is to do a read immediately after the write and make
  * sure those two instructions are in the same cache line.