amd64: wrap 64bit sigtramp into vdso

Reviewed by:	emaste
Discussed with:	jrtc27
Tested by:	pho
Sponsored by:	The FreeBSD Foundation
MFC after:	1 month
Differential revision:	https://reviews.freebsd.org/D32960

2 files changed, 107 insertions, 0 deletions

diff --git a/sys/tools/amd64_vdso.sh b/sys/tools/amd64_vdso.sh
new file mode 100644
index 000000000000..39406eccd2ef
--- /dev/null
+++ b/sys/tools/amd64_vdso.sh
@@ -0,0 +1,59 @@
+#!/bin/sh
+# SPDX-License-Identifier: BSD-2-Clause-FreeBSD
+#
+# Copyright (c) 2021 The FreeBSD Foundation
+# All rights reserved.
+#
+# This software was developed by Konstantin Belousov <kib@FreeBSD.org>
+# under sponsorship from the FreeBSD Foundation.
+#
+# 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.
+
+set -e
+
+${CC} -x assembler-with-cpp -DLOCORE -fPIC -nostdinc -c \
+   -o sigtramp.pico -I. -I"${S}" -include opt_global.h \
+   "${S}"/amd64/amd64/sigtramp.S
+
+# We need to make vdso as compact as possible, for it to leave space
+# for other things in the shared page.  For this, we pack everything
+# into single loadable segment.
+#
+# -z rodynamic is undocumented lld-specific option, seemingly required
+# for lld to avoid putting dynamic into dedicated writeable segment,
+# despite ldscript placement.  It is ignored by ld.bfd but ldscript
+# alone is enough there.
+#
+${LD} --shared -Bsymbolic -soname="elf-vdso.so.1" \
+   -T "${S}"/conf/vdso_amd64.ldscript \
+   --eh-frame-hdr --no-undefined -z rodynamic -z norelro -nmagic \
+   --hash-style=sysv --fatal-warnings --strip-all \
+   -o elf-vdso.so.1 sigtramp.pico
+
+${CC} -x assembler-with-cpp -DLOCORE -fPIC -nostdinc -c \
+   -o elf-vdso.so.o -I. -I"${S}" -include opt_global.h \
+   -DVDSO_NAME=elf_vdso_so_1 -DVDSO_FILE=elf-vdso.so.1 \
+   "${S}"/tools/vdso_wrap.S
+
+${NM} -D elf-vdso.so.1 | \
+   awk '/__vdso_sigcode/{printf "#define VDSO_SIGCODE_OFFSET 0x%s\n",$1}' \
+   >vdso_offsets.h
diff --git a/sys/tools/vdso_wrap.S b/sys/tools/vdso_wrap.S
new file mode 100644
index 000000000000..807dcf9c06f4
--- /dev/null
+++ b/sys/tools/vdso_wrap.S
@@ -0,0 +1,48 @@
+/*-
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright (c) 2021 The FreeBSD Foundation
+ *
+ * This software was developed by Konstantin Belousov <kib@FreeBSD.org>
+ * under sponsorship from the FreeBSD Foundation.
+ *
+ * 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 <sys/cdefs.h>
+
+#define	VDSO_BLOB_START(S)	__CONCAT(_binary_, __CONCAT(S, _start))
+#define	VDSO_BLOB_END(S)	__CONCAT(_binary_, __CONCAT(S, _end))
+#define	VDSO_BLOB_SIZE(S)	__CONCAT(_binary_, __CONCAT(S, _size))
+
+	.section .rodata, "a", %progbits
+	.globl	VDSO_BLOB_START(VDSO_NAME)
+	.type	VDSO_BLOB_START(VDSO_NAME), %object
+	.size	VDSO_BLOB_START(VDSO_NAME), 0
+VDSO_BLOB_START(VDSO_NAME):
+	.incbin	__XSTRING(VDSO_FILE)
+	.globl	VDSO_BLOB_END(VDSO_NAME)
+	.type	VDSO_BLOB_END(VDSO_NAME), %object
+	.size	VDSO_BLOB_END(VDSO_NAME), 0
+VDSO_BLOB_END(VDSO_NAME):
+	.globl	VDSO_BLOB_SIZE(VDSO_NAME)
+	.set	VDSO_BLOB_SIZE(VDSO_NAME), . - VDSO_BLOB_START(VDSO_NAME)