diff --git a/lib/csu/Makefile.inc b/lib/csu/Makefile.inc
--- a/lib/csu/Makefile.inc
+++ b/lib/csu/Makefile.inc
@@ -20,7 +20,6 @@
 ACFLAGS+=	-DLOCORE
 
 CFLAGS+=	-DSTRIP_FBSDID
-CFLAGS+=	-fno-asynchronous-unwind-tables
 CFLAGS+=	-fno-omit-frame-pointer
 CFLAGS+=	-I${.CURDIR:H}/common \
 		-I${SRCTOP}/lib/libc/include
diff --git a/lib/csu/aarch64/crt1_c.c b/lib/csu/aarch64/crt1_c.c
--- a/lib/csu/aarch64/crt1_c.c
+++ b/lib/csu/aarch64/crt1_c.c
@@ -35,7 +35,8 @@
 #include "libc_private.h"
 #include "csu_common.h"
 
-void __start(int, char **, char **, void (*)(void)) __dead2;
+void _start(int, char **, char **, void (*)(void)) __hidden __dead2;
+void __start(int, char **, char **, void (*)(void)) __hidden __dead2;
 
 /* The entry function. */
 void
diff --git a/lib/csu/aarch64/crt1_s.S b/lib/csu/aarch64/crt1_s.S
--- a/lib/csu/aarch64/crt1_s.S
+++ b/lib/csu/aarch64/crt1_s.S
@@ -33,12 +33,15 @@
 __FBSDID("$FreeBSD$");
 
 ENTRY(_start)
+	.cfi_undefined x30
+	mov	x29,#0
+	mov	x30,#0
 	mov	x3, x2		/* cleanup */
 	add	x1, x0, #8	/* load argv */
 	ldr	x0, [x0]	/* load argc */
 	add	x2, x1, x0, lsl #3 /* env is after argv */
 	add	x2, x2, #8	/* argv is null terminated */
-	b	 __start
+	bl	 __start
 END(_start)
 
 	.section .note.GNU-stack,"",@progbits
diff --git a/lib/csu/amd64/Makefile b/lib/csu/amd64/Makefile
--- a/lib/csu/amd64/Makefile
+++ b/lib/csu/amd64/Makefile
@@ -5,4 +5,6 @@
 CFLAGS+=	-I${.CURDIR}
 CFLAGS+=	-fno-omit-frame-pointer
 
+CRT1OBJS+=	crt1_s.o
+
 .include <bsd.lib.mk>
diff --git a/lib/csu/amd64/crt1_c.c b/lib/csu/amd64/crt1_c.c
--- a/lib/csu/amd64/crt1_c.c
+++ b/lib/csu/amd64/crt1_c.c
@@ -32,11 +32,12 @@
 #include "libc_private.h"
 #include "csu_common.h"
 
-void _start(char **, void (*)(void)) __dead2;
+void _start(char **, void (*)(void)) __hidden __dead2;
+void _start1(char **, void (*)(void)) __hidden __dead2;
 
 /* The entry function. */
 void
-_start(char **ap, void (*cleanup)(void))
+_start1(char **ap, void (*cleanup)(void))
 {
 	int argc;
 	char **argv;
diff --git a/lib/csu/amd64/crt1_s.S b/lib/csu/amd64/crt1_s.S
new file mode 100644
--- /dev/null
+++ b/lib/csu/amd64/crt1_s.S
@@ -0,0 +1,43 @@
+/*-
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright (C) 2023 Dmitry Chagin <dchagin@FreeBSD.org>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <machine/asm.h>
+
+        .text
+
+ENTRY(_start)
+	.cfi_undefined %rip	/* Terminate call stack. */
+	.cfi_def_cfa %rsp, 0
+	xorq	%rbp,%rbp
+	pushq	%rbp		/* Align stack. */
+	.cfi_def_cfa_offset 8
+	movq	%rsp,%rbp
+	.cfi_offset %rbp, -8
+	callq	_start1
+END(_start)
+
+	.section .note.GNU-stack,"",%progbits
diff --git a/lib/csu/i386/crt1_s.S b/lib/csu/i386/crt1_s.S
--- a/lib/csu/i386/crt1_s.S
+++ b/lib/csu/i386/crt1_s.S
@@ -31,6 +31,7 @@
 	.type	_start, @function
 _start:
 	.cfi_startproc
+	.cfi_undefined %eip
 	xorl	%ebp,%ebp
 	pushl	%ebp
 	.cfi_def_cfa_offset 4