[PATCH v18 15/15] selftests, arm64: add a selftest for passing tagged pointers to kernel

From: Andrey Konovalov <andreyknvl@google.com>
To: linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org,
	linux-kernel@vger.kernel.org, amd-gfx@lists.freedesktop.org,
	dri-devel@lists.freedesktop.org, linux-rdma@vger.kernel.org,
	linux-media@vger.kernel.org, kvm@vger.kernel.org,
	linux-kselftest@vger.kernel.org
Cc: Catalin Marinas <catalin.marinas@arm.com>,
	Vincenzo Frascino <vincenzo.frascino@arm.com>,
	Will Deacon <will.deacon@arm.com>,
	Mark Rutland <mark.rutland@arm.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Kees Cook <keescook@chromium.org>,
	Yishai Hadas <yishaih@mellanox.com>,
	Felix Kuehling <Felix.Kuehling@amd.com>,
	Alexander Deucher <Alexander.Deucher@amd.com>,
	Christian Koenig <Christian.Koenig@amd.com>,
	Mauro Carvalho Chehab <mchehab@kernel.org>,
	Jens Wiklander <jens.wiklander@linaro.org>,
	Alex Williamson <alex.williamson@redhat.com>,
	Leon Romanovsky <leon@kernel.org>,
	Luc Van Oostenryck <luc.vanoostenryck@gmail.com>,
	Dave Martin <Dave.Martin@arm.com>,
	Khalid Aziz <khalid.aziz@oracle.com>, enh <enh@>
Subject: [PATCH v18 15/15] selftests, arm64: add a selftest for passing tagged pointers to kernel
Date: Mon, 24 Jun 2019 16:33:00 +0200	[thread overview]
Message-ID: <0999c80cd639b78ae27c0674069d552833227564.1561386715.git.andreyknvl@google.com> (raw)
In-Reply-To: <cover.1561386715.git.andreyknvl@google.com>

This patch is a part of a series that extends kernel ABI to allow to pass
tagged user pointers (with the top byte set to something else other than
0x00) as syscall arguments.

This patch adds a simple test, that calls the uname syscall with a
tagged user pointer as an argument. Without the kernel accepting tagged
user pointers the test fails with EFAULT.

Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
---
 tools/testing/selftests/arm64/.gitignore      |  1 +
 tools/testing/selftests/arm64/Makefile        | 11 +++++++
 .../testing/selftests/arm64/run_tags_test.sh  | 12 ++++++++
 tools/testing/selftests/arm64/tags_test.c     | 29 +++++++++++++++++++
 4 files changed, 53 insertions(+)
 create mode 100644 tools/testing/selftests/arm64/.gitignore
 create mode 100644 tools/testing/selftests/arm64/Makefile
 create mode 100755 tools/testing/selftests/arm64/run_tags_test.sh
 create mode 100644 tools/testing/selftests/arm64/tags_test.c

diff --git a/tools/testing/selftests/arm64/.gitignore b/tools/testing/selftests/arm64/.gitignore
new file mode 100644
index 000000000000..e8fae8d61ed6
--- /dev/null
+++ b/tools/testing/selftests/arm64/.gitignore
@@ -0,0 +1 @@
+tags_test
diff --git a/tools/testing/selftests/arm64/Makefile b/tools/testing/selftests/arm64/Makefile
new file mode 100644
index 000000000000..a61b2e743e99
--- /dev/null
+++ b/tools/testing/selftests/arm64/Makefile
@@ -0,0 +1,11 @@
+# SPDX-License-Identifier: GPL-2.0
+
+# ARCH can be overridden by the user for cross compiling
+ARCH ?= $(shell uname -m 2>/dev/null || echo not)
+
+ifneq (,$(filter $(ARCH),aarch64 arm64))
+TEST_GEN_PROGS := tags_test
+TEST_PROGS := run_tags_test.sh
+endif
+
+include ../lib.mk
diff --git a/tools/testing/selftests/arm64/run_tags_test.sh b/tools/testing/selftests/arm64/run_tags_test.sh
new file mode 100755
index 000000000000..745f11379930
--- /dev/null
+++ b/tools/testing/selftests/arm64/run_tags_test.sh
@@ -0,0 +1,12 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+
+echo "--------------------"
+echo "running tags test"
+echo "--------------------"
+./tags_test
+if [ $? -ne 0 ]; then
+	echo "[FAIL]"
+else
+	echo "[PASS]"
+fi
diff --git a/tools/testing/selftests/arm64/tags_test.c b/tools/testing/selftests/arm64/tags_test.c
new file mode 100644
index 000000000000..22a1b266e373
--- /dev/null
+++ b/tools/testing/selftests/arm64/tags_test.c
@@ -0,0 +1,29 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <stdint.h>
+#include <sys/prctl.h>
+#include <sys/utsname.h>
+
+#define SHIFT_TAG(tag)		((uint64_t)(tag) << 56)
+#define SET_TAG(ptr, tag)	(((uint64_t)(ptr) & ~SHIFT_TAG(0xff)) | \
+					SHIFT_TAG(tag))
+
+int main(void)
+{
+	static int tbi_enabled = 0;
+	struct utsname *ptr, *tagged_ptr;
+	int err;
+
+	if (prctl(PR_SET_TAGGED_ADDR_CTRL, PR_TAGGED_ADDR_ENABLE, 0, 0, 0) == 0)
+		tbi_enabled = 1;
+	ptr = (struct utsname *)malloc(sizeof(*ptr));
+	if (tbi_enabled)
+		tagged_ptr = (struct utsname *)SET_TAG(ptr, 0x42);
+	err = uname(tagged_ptr);
+	free(ptr);
+
+	return err;
+}
-- 
2.22.0.410.gd8fdbe21b5-goog
