diff --git a/lib/libc/sparc64/sys/Makefile.inc b/lib/libc/sparc64/sys/Makefile.inc
index f677df19d1ba..8e5901e98b6b 100644
--- a/lib/libc/sparc64/sys/Makefile.inc
+++ b/lib/libc/sparc64/sys/Makefile.inc
@@ -11,6 +11,9 @@ SRCS+=	__sparc_sigtramp_setup.c \
 	sigcode.S
 
 CFLAGS+= -I${.CURDIR}/sparc64/fpu
+.if ${MACHINE} == "sun4v"
+CFLAGS+= -DSUN4V
+.endif
 
 MDASM+=	brk.S cerror.S exect.S pipe.S ptrace.S sbrk.S setlogin.S sigaction.S
 
diff --git a/lib/libc/sparc64/sys/__sparc_utrap_gen.S b/lib/libc/sparc64/sys/__sparc_utrap_gen.S
index 6f6f0e3d2c57..4fb128dd3f6a 100644
--- a/lib/libc/sparc64/sys/__sparc_utrap_gen.S
+++ b/lib/libc/sparc64/sys/__sparc_utrap_gen.S
@@ -38,6 +38,10 @@ __FBSDID("$FreeBSD$");
 #include "assym.s"
 
 ENTRY(__sparc_utrap_gen)
+#ifdef SUN4V
+	save
+	ta	%xcc, ST_FPEMU_CONTEXT
+#endif	
 	sub	%sp, UF_SIZEOF, %sp
 
 	stx	%o0, [%sp + SPOFF + CCFSZ + UF_TYPE]