When servicing a memory error on the sun4/sun4c make

sure the store buffers on the chip are completely flushed to ensure
proper handler completion.

2 files changed, 23 insertions, 1 deletions

diff --git a/sys/arch/sparc/sparc/locore.s b/sys/arch/sparc/sparc/locore.s
index 0ada5b63f1f..ddf44c3a459 100644
--- a/sys/arch/sparc/sparc/locore.s
+++ b/sys/arch/sparc/sparc/locore.s
@@ -3458,6 +3458,25 @@ Lcopyfault:
 	jmp	%g7 + 8
 	 mov	EFAULT, %o0
 
+/* Force the cpu to complete all pending store operations
+ * and flush it's on chip write buffers.  This is the sun4c/sun4
+ * version and will only be called when servicing a memory
+ * error so that we do not loop indefinately.
+ */
+ENTRY(sun4c_sun4_storebuf_flush)
+	set	AC_CONTEXT, %o1
+	lduba	[%o1] ASI_CONTROL, %o0	! load context reg
+	stba	%o0, [%o1] ASI_CONTROL	! store same value, flush begins
+	nop
+	nop
+	nop
+	/* Pipeline is now clear */
+	nop
+	nop
+	nop
+	/* Store buffer is empty, safe to return now. */
+	retl
+	 nop
 
 /*
  * Write all user windows presently in the CPU back to the user's stack.
diff --git a/sys/arch/sparc/sparc/memreg.c b/sys/arch/sparc/sparc/memreg.c
index b66b899cba9..8c2a3e95b6a 100644
--- a/sys/arch/sparc/sparc/memreg.c
+++ b/sys/arch/sparc/sparc/memreg.c
@@ -105,11 +105,14 @@ memregattach(parent, self, aux)
  * Should kill the process that got its bits clobbered,
  * and take the page out of the page pool, but for now...
  */
+
+extern void sun4c_sun4_storebuf_flush(void);
+
 void
 memerr(issync, ser, sva, aer, ava)
 	int issync, ser, sva, aer, ava;
 {
-
+	sun4c_sun4_storebuf_flush(); /* prevent loops... */
 	if (cputyp == CPU_SUN4) {
 		if (par_err_reg) {
 			printf("mem err: ser=%b sva=%x\n", ser, SER_BITS, sva);