diff --git a/cddl/contrib/opensolaris/lib/libdtrace/common/dt_open.c b/cddl/contrib/opensolaris/lib/libdtrace/common/dt_open.c
--- a/cddl/contrib/opensolaris/lib/libdtrace/common/dt_open.c
+++ b/cddl/contrib/opensolaris/lib/libdtrace/common/dt_open.c
@@ -466,8 +466,10 @@ static const dt_ident_t _dtrace_globals[
 #if defined(sun)
 { "uaddr", DT_IDENT_ACTFUNC, 0, DT_ACT_UADDR, DT_ATTR_STABCMN,
 	DT_VERS_1_2, &dt_idops_func, "_usymaddr(uintptr_t)" },
+#endif
 { "ucaller", DT_IDENT_SCALAR, 0, DIF_VAR_UCALLER, DT_ATTR_STABCMN,
 	DT_VERS_1_2, &dt_idops_type, "uint64_t" },
+#if defined(sun)
 { "ufunc", DT_IDENT_ACTFUNC, 0, DT_ACT_USYM, DT_ATTR_STABCMN,
 	DT_VERS_1_2, &dt_idops_func, "_usymaddr(uintptr_t)" },
 #endif
diff --git a/sys/cddl/contrib/opensolaris/uts/common/dtrace/dtrace.c b/sys/cddl/contrib/opensolaris/uts/common/dtrace/dtrace.c
--- a/sys/cddl/contrib/opensolaris/uts/common/dtrace/dtrace.c
+++ b/sys/cddl/contrib/opensolaris/uts/common/dtrace/dtrace.c
@@ -2909,7 +2909,6 @@ dtrace_dif_variable(dtrace_mstate_t *mst
 		}
 		return (mstate->dtms_caller);
 
-#if defined(sun)
 	case DIF_VAR_UCALLER:
 		if (!dtrace_priv_proc(state))
 			return (0);
@@ -2933,7 +2932,6 @@ dtrace_dif_variable(dtrace_mstate_t *mst
 		}
 
 		return (mstate->dtms_ucaller);
-#endif
 
 	case DIF_VAR_PROBEPROV:
 		ASSERT(mstate->dtms_present & DTRACE_MSTATE_PROBE);
diff --git a/sys/cddl/dev/dtrace/amd64/dtrace_isa.c b/sys/cddl/dev/dtrace/amd64/dtrace_isa.c
--- a/sys/cddl/dev/dtrace/amd64/dtrace_isa.c
+++ b/sys/cddl/dev/dtrace/amd64/dtrace_isa.c
@@ -143,7 +143,7 @@ dtrace_getupcstack(uint64_t *pcstack, in
 {
 	proc_t *p = curproc;
 	struct trapframe *tf;
-	uintptr_t pc, sp;
+	uintptr_t pc, sp, fp;
 	volatile uint16_t *flags =
 	    (volatile uint16_t *)&cpu_core[curcpu].cpuc_dtrace_flags;
 	int n;
@@ -167,18 +167,28 @@ dtrace_getupcstack(uint64_t *pcstack, in
 		return;
 
 	pc = tf->tf_rip;
+	fp = tf->tf_rbp;
 	sp = tf->tf_rsp;
 
 	if (DTRACE_CPUFLAG_ISSET(CPU_DTRACE_ENTRY)) {
+		/* 
+		 * In an entry probe.  The frame pointer has not yet been
+		 * pushed (that happens in the function prologue).  The
+		 * best approach is to add the current pc as a missing top
+		 * of stack and back the pc up to the caller, which is stored
+		 * at the current stack pointer address since the call 
+		 * instruction puts it there right before the branch.
+		 */
+
 		*pcstack++ = (uint64_t)pc;
 		pcstack_limit--;
 		if (pcstack_limit <= 0)
 			return;
 
-		pc = dtrace_fulword((void *) sp);
+		pc = dtrace_fuword64((void *) sp);
 	}
 
-	n = dtrace_getustack_common(pcstack, pcstack_limit, pc, sp);
+	n = dtrace_getustack_common(pcstack, pcstack_limit, pc, fp);
 	ASSERT(n >= 0);
 	ASSERT(n <= pcstack_limit);
 
diff --git a/sys/cddl/dev/dtrace/i386/dtrace_isa.c b/sys/cddl/dev/dtrace/i386/dtrace_isa.c
--- a/sys/cddl/dev/dtrace/i386/dtrace_isa.c
+++ b/sys/cddl/dev/dtrace/i386/dtrace_isa.c
@@ -193,14 +193,12 @@ dtrace_getustack_common(uint64_t *pcstac
 	return (ret);
 }
 
-#ifdef notyet
 void
 dtrace_getupcstack(uint64_t *pcstack, int pcstack_limit)
 {
-	klwp_t *lwp = ttolwp(curthread);
 	proc_t *p = curproc;
-	struct regs *rp;
-	uintptr_t pc, sp;
+	struct trapframe *tf;
+	uintptr_t pc, sp, fp;
 	volatile uint16_t *flags =
 	    (volatile uint16_t *)&cpu_core[curcpu].cpuc_dtrace_flags;
 	int n;
@@ -214,7 +212,7 @@ dtrace_getupcstack(uint64_t *pcstack, in
 	/*
 	 * If there's no user context we still need to zero the stack.
 	 */
-	if (lwp == NULL || p == NULL || (rp = lwp->lwp_regs) == NULL)
+	if (p == NULL || (tf = curthread->td_frame) == NULL)
 		goto zero;
 
 	*pcstack++ = (uint64_t)p->p_pid;
@@ -223,19 +221,26 @@ dtrace_getupcstack(uint64_t *pcstack, in
 	if (pcstack_limit <= 0)
 		return;
 
-	pc = rp->r_pc;
-	sp = rp->r_fp;
+	pc = tf->tf_eip;
+	fp = tf->tf_ebp;
+	sp = tf->tf_esp;
 
 	if (DTRACE_CPUFLAG_ISSET(CPU_DTRACE_ENTRY)) {
+		/*
+		 * In an entry probe.  The frame pointer has not yet been
+		 * pushed (that happens in the function prologue).  The
+		 * best approach is to add the current pc as a missing top
+		 * of stack and back the pc up to the caller, which is stored
+		 * at the current stack pointer address since the call 
+		 * instruction puts it there right before the branch.
+		 */
+
 		*pcstack++ = (uint64_t)pc;
 		pcstack_limit--;
 		if (pcstack_limit <= 0)
 			return;
 
-		if (p->p_model == DATAMODEL_NATIVE)
-			pc = dtrace_fulword((void *)rp->r_sp);
-		else
-			pc = dtrace_fuword32((void *)rp->r_sp);
+		pc = dtrace_fuword32((void *) sp);
 	}
 
 	n = dtrace_getustack_common(pcstack, pcstack_limit, pc, sp);
@@ -247,9 +252,8 @@ dtrace_getupcstack(uint64_t *pcstack, in
 
 zero:
 	while (pcstack_limit-- > 0)
-		*pcstack++ = NULL;
+		*pcstack++ = 0;
 }
-#endif /* notyet */
 
 int
 dtrace_getustackdepth(void)