From 4a423645bc2690376a7a94b4bb7b2f74bc6206ff Mon Sep 17 00:00:00 2001
From: Andre Przywara
Date: Fri, 19 Mar 2021 16:53:24 +0000
Subject: kselftest/arm64: mte: Fix compilation with native compiler

The mte selftest Makefile contains a check for GCC, to add the memtag
-march flag to the compiler options. This check fails if the compiler
is not explicitly specified, so reverts to the standard "cc", in which
case --version doesn't mention the "gcc" string we match against:
$ cc --version | head -n 1
cc (Ubuntu 9.3.0-17ubuntu1~20.04) 9.3.0

This will not add the -march switch to the command line, so compilation
fails:
mte_helper.S: Assembler messages:
mte_helper.S:25: Error: selected processor does not support `irg x0,x0,xzr'
mte_helper.S:38: Error: selected processor does not support `gmi x1,x0,xzr'
...

Actually clang accepts the same -march option as well, so we can just
drop this check and add this unconditionally to the command line, to avoid
any future issues with this check altogether (gcc actually prints
basename(argv[0]) when called with --version).

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Mark Brown <broone@kernel.org>
Link: https://lore.kernel.org/r/20210319165334.29213-2-andre.przywara@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
---
 tools/testing/selftests/arm64/mte/Makefile | 2 --
 1 file changed, 2 deletions(-)

(limited to 'tools')

diff --git a/tools/testing/selftests/arm64/mte/Makefile b/tools/testing/selftests/arm64/mte/Makefile
index 0b3af552632a..df15d44aeb8d 100644
--- a/tools/testing/selftests/arm64/mte/Makefile
+++ b/tools/testing/selftests/arm64/mte/Makefile
@@ -6,9 +6,7 @@ SRCS := $(filter-out mte_common_util.c,$(wildcard *.c))
 PROGS := $(patsubst %.c,%,$(SRCS))
 
 #Add mte compiler option
-ifneq ($(shell $(CC) --version 2>&1 | head -n 1 | grep gcc),)
 CFLAGS += -march=armv8.5-a+memtag
-endif
 
 #check if the compiler works well
 mte_cc_support := $(shell if ($(CC) $(CFLAGS) -E -x c /dev/null -o /dev/null 2>&1) then echo "1"; fi)
-- 
cgit v1.2.3


From e5decefd884da1c2c6ea18fca17b80b189afcc43 Mon Sep 17 00:00:00 2001
From: Andre Przywara
Date: Fri, 19 Mar 2021 16:53:25 +0000
Subject: kselftest/arm64: mte: Fix pthread linking

The GCC manual suggests to use -pthread, when linking with the PThread
library, also to add this switch to both the compilation and linking
stages.

Do as the manual says, to fix compilation with Ubuntu's 20.04 toolchain,
which was getting -lpthread too early on the command line:
------------
/usr/bin/ld: /tmp/cc5zbo2A.o: in function `execute_test':
tools/testing/selftests/arm64/mte/check_gcr_el1_cswitch.c:86:
	undefined reference to `pthread_create'
/usr/bin/ld: tools/testing/selftests/arm64/mte/check_gcr_el1_cswitch.c:90:
	undefined reference to `pthread_join'
------------

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Mark Brown <broone@kernel.org>
Link: https://lore.kernel.org/r/20210319165334.29213-3-andre.przywara@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
---
 tools/testing/selftests/arm64/mte/Makefile | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

(limited to 'tools')

diff --git a/tools/testing/selftests/arm64/mte/Makefile b/tools/testing/selftests/arm64/mte/Makefile
index df15d44aeb8d..90aadd86fa0d 100644
--- a/tools/testing/selftests/arm64/mte/Makefile
+++ b/tools/testing/selftests/arm64/mte/Makefile
@@ -1,7 +1,8 @@
 # SPDX-License-Identifier: GPL-2.0
 # Copyright (C) 2020 ARM Limited
 
-CFLAGS += -std=gnu99 -I. -lpthread
+CFLAGS += -std=gnu99 -I. -pthread
+LDFLAGS += -pthread
 SRCS := $(filter-out mte_common_util.c,$(wildcard *.c))
 PROGS := $(patsubst %.c,%,$(SRCS))
 
-- 
cgit v1.2.3


From 31c88729a7ad2b9871e6a73e491ec7223880d633 Mon Sep 17 00:00:00 2001
From: Andre Przywara
Date: Fri, 19 Mar 2021 16:53:26 +0000
Subject: kselftest/arm64: mte: ksm_options: Fix fscanf warning

Out of the box Ubuntu's 20.04 compiler warns about missing return value
checks for fscanf() calls.

Make GCC happy by checking whether we actually parsed one integer.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Mark Brown <broone@kernel.org>
Link: https://lore.kernel.org/r/20210319165334.29213-4-andre.przywara@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
---
 tools/testing/selftests/arm64/mte/check_ksm_options.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

(limited to 'tools')

diff --git a/tools/testing/selftests/arm64/mte/check_ksm_options.c b/tools/testing/selftests/arm64/mte/check_ksm_options.c
index 3b23c4d61d38..88c74bc46d4f 100644
--- a/tools/testing/selftests/arm64/mte/check_ksm_options.c
+++ b/tools/testing/selftests/arm64/mte/check_ksm_options.c
@@ -33,7 +33,10 @@ static unsigned long read_sysfs(char *str)
 		ksft_print_msg("ERR: missing %s\n", str);
 		return 0;
 	}
-	fscanf(f, "%lu", &val);
+	if (fscanf(f, "%lu", &val) != 1) {
+		ksft_print_msg("ERR: parsing %s\n", str);
+		val = 0;
+	}
 	fclose(f);
 	return val;
 }
-- 
cgit v1.2.3


From 46cb11b17c7a917e0eb5c7aa87a7bc6cda455a5e Mon Sep 17 00:00:00 2001
From: Andre Przywara
Date: Fri, 19 Mar 2021 16:53:27 +0000
Subject: kselftest/arm64: mte: user_mem: Fix write() warning

Out of the box Ubuntu's 20.04 compiler warns about missing return value
checks for write() (sys)calls.

Make GCC happy by checking whether we actually managed to write "val".

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Mark Brown <broone@kernel.org>
Link: https://lore.kernel.org/r/20210319165334.29213-5-andre.przywara@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
---
 tools/testing/selftests/arm64/mte/check_user_mem.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

(limited to 'tools')

diff --git a/tools/testing/selftests/arm64/mte/check_user_mem.c b/tools/testing/selftests/arm64/mte/check_user_mem.c
index 4bfa80f2a8c3..1de7a0abd0ae 100644
--- a/tools/testing/selftests/arm64/mte/check_user_mem.c
+++ b/tools/testing/selftests/arm64/mte/check_user_mem.c
@@ -33,7 +33,8 @@ static int check_usermem_access_fault(int mem_type, int mode, int mapping)
 	if (fd == -1)
 		return KSFT_FAIL;
 	for (i = 0; i < len; i++)
-		write(fd, &val, sizeof(val));
+		if (write(fd, &val, sizeof(val)) != sizeof(val))
+			return KSFT_FAIL;
 	lseek(fd, 0, 0);
 	ptr = mte_allocate_memory(len, mem_type, mapping, true);
 	if (check_allocated_memory(ptr, len, mem_type, true) != KSFT_PASS) {
-- 
cgit v1.2.3


From d302a702530b4025fbb14f20e637badce28bc741 Mon Sep 17 00:00:00 2001
From: Andre Przywara
Date: Fri, 19 Mar 2021 16:53:28 +0000
Subject: kselftest/arm64: mte: common: Fix write() warnings

Out of the box Ubuntu's 20.04 compiler warns about missing return value
checks for write() (sys)calls.

Make GCC happy by checking whether we actually managed to write out our
buffer.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Mark Brown <broone@kernel.org>
Link: https://lore.kernel.org/r/20210319165334.29213-6-andre.przywara@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
---
 .../testing/selftests/arm64/mte/mte_common_util.c  | 23 +++++++++++++++++-----
 1 file changed, 18 insertions(+), 5 deletions(-)

(limited to 'tools')

diff --git a/tools/testing/selftests/arm64/mte/mte_common_util.c b/tools/testing/selftests/arm64/mte/mte_common_util.c
index 39f8908988ea..4e887dad762d 100644
--- a/tools/testing/selftests/arm64/mte/mte_common_util.c
+++ b/tools/testing/selftests/arm64/mte/mte_common_util.c
@@ -181,10 +181,17 @@ void *mte_allocate_file_memory(size_t size, int mem_type, int mapping, bool tags
 	}
 	/* Initialize the file for mappable size */
 	lseek(fd, 0, SEEK_SET);
-	for (index = INIT_BUFFER_SIZE; index < size; index += INIT_BUFFER_SIZE)
-		write(fd, buffer, INIT_BUFFER_SIZE);
+	for (index = INIT_BUFFER_SIZE; index < size; index += INIT_BUFFER_SIZE) {
+		if (write(fd, buffer, INIT_BUFFER_SIZE) != INIT_BUFFER_SIZE) {
+			perror("initialising buffer");
+			return NULL;
+		}
+	}
 	index -= INIT_BUFFER_SIZE;
-	write(fd, buffer, size - index);
+	if (write(fd, buffer, size - index) != size - index) {
+		perror("initialising buffer");
+		return NULL;
+	}
 	return __mte_allocate_memory_range(size, mem_type, mapping, 0, 0, tags, fd);
 }
 
@@ -202,9 +209,15 @@ void *mte_allocate_file_memory_tag_range(size_t size, int mem_type, int mapping,
 	/* Initialize the file for mappable size */
 	lseek(fd, 0, SEEK_SET);
 	for (index = INIT_BUFFER_SIZE; index < map_size; index += INIT_BUFFER_SIZE)
-		write(fd, buffer, INIT_BUFFER_SIZE);
+		if (write(fd, buffer, INIT_BUFFER_SIZE) != INIT_BUFFER_SIZE) {
+			perror("initialising buffer");
+			return NULL;
+		}
 	index -= INIT_BUFFER_SIZE;
-	write(fd, buffer, map_size - index);
+	if (write(fd, buffer, map_size - index) != map_size - index) {
+		perror("initialising buffer");
+		return NULL;
+	}
 	return __mte_allocate_memory_range(size, mem_type, mapping, range_before,
 					   range_after, true, fd);
 }
-- 
cgit v1.2.3


From 592432862cc4019075a7196d9961562c49507d6f Mon Sep 17 00:00:00 2001
From: Andre Przywara
Date: Fri, 19 Mar 2021 16:53:29 +0000
Subject: kselftest/arm64: mte: Fix MTE feature detection

To check whether the CPU and kernel support the MTE features we want
to test, we use an (emulated) CPU ID register read. However we only
check against a very particular feature version (0b0010), even though
the ARM ARM promises ID register features to be backwards compatible.

While this could be fixed by using ">=" instead of "==", we should
actually use the explicit HWCAP2_MTE hardware capability, exposed by the
kernel via the ELF auxiliary vectors.

That moves this responsibility to the kernel, and fixes running the
tests on machines with FEAT_MTE3 capability.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Mark Brown <broone@kernel.org>
Link: https://lore.kernel.org/r/20210319165334.29213-7-andre.przywara@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
---
 tools/testing/selftests/arm64/mte/mte_common_util.c | 13 ++-----------
 1 file changed, 2 insertions(+), 11 deletions(-)

(limited to 'tools')

diff --git a/tools/testing/selftests/arm64/mte/mte_common_util.c b/tools/testing/selftests/arm64/mte/mte_common_util.c
index 4e887dad762d..aa8a8a6b8b6d 100644
--- a/tools/testing/selftests/arm64/mte/mte_common_util.c
+++ b/tools/testing/selftests/arm64/mte/mte_common_util.c
@@ -291,22 +291,13 @@ int mte_switch_mode(int mte_option, unsigned long incl_mask)
 	return 0;
 }
 
-#define ID_AA64PFR1_MTE_SHIFT		8
-#define ID_AA64PFR1_MTE			2
-
 int mte_default_setup(void)
 {
-	unsigned long hwcaps = getauxval(AT_HWCAP);
+	unsigned long hwcaps2 = getauxval(AT_HWCAP2);
 	unsigned long en = 0;
 	int ret;
 
-	if (!(hwcaps & HWCAP_CPUID)) {
-		ksft_print_msg("FAIL: CPUID registers unavailable\n");
-		return KSFT_FAIL;
-	}
-	/* Read ID_AA64PFR1_EL1 register */
-	asm volatile("mrs %0, id_aa64pfr1_el1" : "=r"(hwcaps) : : "memory");
-	if (((hwcaps >> ID_AA64PFR1_MTE_SHIFT) & MT_TAG_MASK) != ID_AA64PFR1_MTE) {
+	if (!(hwcaps2 & HWCAP2_MTE)) {
 		ksft_print_msg("FAIL: MTE features unavailable\n");
 		return KSFT_SKIP;
 	}
-- 
cgit v1.2.3


From 5238c2cd5a2e0dc846d1b900553211e832952b8d Mon Sep 17 00:00:00 2001
From: Andre Przywara
Date: Fri, 19 Mar 2021 16:53:30 +0000
Subject: kselftest/arm64: mte: Use cross-compiler if specified

At the moment we either need to provide CC explicitly, or use a native
machine to get the ARM64 MTE selftest compiled.

It seems useful to use the same (cross-)compiler as we use for the
kernel, so copy the recipe we use in the pauth selftest.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Mark Brown <broone@kernel.org>
Link: https://lore.kernel.org/r/20210319165334.29213-8-andre.przywara@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
---
 tools/testing/selftests/arm64/mte/Makefile | 5 +++++
 1 file changed, 5 insertions(+)

(limited to 'tools')

diff --git a/tools/testing/selftests/arm64/mte/Makefile b/tools/testing/selftests/arm64/mte/Makefile
index 90aadd86fa0d..fa282e5f2069 100644
--- a/tools/testing/selftests/arm64/mte/Makefile
+++ b/tools/testing/selftests/arm64/mte/Makefile
@@ -1,6 +1,11 @@
 # SPDX-License-Identifier: GPL-2.0
 # Copyright (C) 2020 ARM Limited
 
+# preserve CC value from top level Makefile
+ifeq ($(CC),cc)
+CC := $(CROSS_COMPILE)gcc
+endif
+
 CFLAGS += -std=gnu99 -I. -pthread
 LDFLAGS += -pthread
 SRCS := $(filter-out mte_common_util.c,$(wildcard *.c))
-- 
cgit v1.2.3


From 8bbb58a3c6b9f12b2217b8ae08e70a6d2f556f73 Mon Sep 17 00:00:00 2001
From: Andre Przywara
Date: Fri, 19 Mar 2021 16:53:31 +0000
Subject: kselftest/arm64: mte: Output warning about failing compiler

At the moment we check the compiler's ability to compile MTE enabled
code, but guard all the Makefile rules by it. As a consequence a broken
or not capable compiler just doesn't do anything, and make happily
returns without any error message, but with no programs created.

Since the MTE feature is only supported by recent aarch64 compilers (not
all stable distro compilers support it), having an explicit message
seems like a good idea. To not break building multiple targets, we let
make proceed without errors.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Mark Brown <broone@kernel.org>
Link: https://lore.kernel.org/r/20210319165334.29213-9-andre.przywara@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
---
 tools/testing/selftests/arm64/mte/Makefile | 3 +++
 1 file changed, 3 insertions(+)

(limited to 'tools')

diff --git a/tools/testing/selftests/arm64/mte/Makefile b/tools/testing/selftests/arm64/mte/Makefile
index fa282e5f2069..e0d43cea3cd1 100644
--- a/tools/testing/selftests/arm64/mte/Makefile
+++ b/tools/testing/selftests/arm64/mte/Makefile
@@ -23,6 +23,9 @@ TEST_GEN_PROGS := $(PROGS)
 
 # Get Kernel headers installed and use them.
 KSFT_KHDR_INSTALL := 1
+else
+    $(warning compiler "$(CC)" does not support the ARMv8.5 MTE extension.)
+    $(warning test program "mte" will not be created.)
 endif
 
 # Include KSFT lib.mk.
-- 
cgit v1.2.3


From 9466ecac84a462fc91d192f0f9be0afd8e4f19f9 Mon Sep 17 00:00:00 2001
From: Andre Przywara
Date: Fri, 19 Mar 2021 16:53:32 +0000
Subject: kselftest/arm64: mte: Makefile: Fix clang compilation

When clang finds a header file on the command line, it wants to
precompile that, which would end up in a separate output file.
Specifying -o on that same command line collides with that effort, so
the compiler complains:

clang: error: cannot specify -o when generating multiple output files

Since we are not really after a precompiled header, just drop the header
file from the command line, by removing it from the list of source
files in the Makefile.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Mark Brown <broone@kernel.org>
Link: https://lore.kernel.org/r/20210319165334.29213-10-andre.przywara@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
---
 tools/testing/selftests/arm64/mte/Makefile | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

(limited to 'tools')

diff --git a/tools/testing/selftests/arm64/mte/Makefile b/tools/testing/selftests/arm64/mte/Makefile
index e0d43cea3cd1..409e3e53d00a 100644
--- a/tools/testing/selftests/arm64/mte/Makefile
+++ b/tools/testing/selftests/arm64/mte/Makefile
@@ -32,5 +32,5 @@ endif
 include ../../lib.mk
 
 ifeq ($(mte_cc_support),1)
-$(TEST_GEN_PROGS): mte_common_util.c mte_common_util.h mte_helper.S
+$(TEST_GEN_PROGS): mte_common_util.c mte_helper.S
 endif
-- 
cgit v1.2.3


From b4e1fa2290691fda4392ac479115ee3b04a7534c Mon Sep 17 00:00:00 2001
From: Andre Przywara
Date: Fri, 19 Mar 2021 16:53:33 +0000
Subject: kselftest/arm64: mte: Fix clang warning

if (!prctl(...) == 0) is not only cumbersome to read, it also upsets
clang and triggers a warning:
------------
mte_common_util.c:287:6: warning: logical not is only applied to the
left hand side of this comparison [-Wlogical-not-parentheses]
....

Fix that by just comparing against "not 0" instead.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Mark Brown <broone@kernel.org>
Link: https://lore.kernel.org/r/20210319165334.29213-11-andre.przywara@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
---
 tools/testing/selftests/arm64/mte/mte_common_util.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

(limited to 'tools')

diff --git a/tools/testing/selftests/arm64/mte/mte_common_util.c b/tools/testing/selftests/arm64/mte/mte_common_util.c
index aa8a8a6b8b6d..040abdca079d 100644
--- a/tools/testing/selftests/arm64/mte/mte_common_util.c
+++ b/tools/testing/selftests/arm64/mte/mte_common_util.c
@@ -284,7 +284,7 @@ int mte_switch_mode(int mte_option, unsigned long incl_mask)
 
 	en |= (incl_mask << PR_MTE_TAG_SHIFT);
 	/* Enable address tagging ABI, mte error reporting mode and tag inclusion mask. */
-	if (!prctl(PR_SET_TAGGED_ADDR_CTRL, en, 0, 0, 0) == 0) {
+	if (prctl(PR_SET_TAGGED_ADDR_CTRL, en, 0, 0, 0) != 0) {
 		ksft_print_msg("FAIL:prctl PR_SET_TAGGED_ADDR_CTRL for mte mode\n");
 		return -EINVAL;
 	}
-- 
cgit v1.2.3


From 75347add03e0fa60ecf2f79e41ec2152b8504593 Mon Sep 17 00:00:00 2001
From: Andre Przywara
Date: Fri, 19 Mar 2021 16:53:34 +0000
Subject: kselftest/arm64: mte: Report filename on failing temp file creation

The MTE selftests create temporary files in /dev/shm, for later mmap-ing
them. When there is no tmpfs mounted on /dev/shm, or /dev/shm does not
exist in the first place (on minimal filesystems), the error message is
not giving good hints:
    # FAIL: Unable to open temporary file
    # FAIL: memory allocation
    not ok 17 Check initial tags with private mapping, ...

Add a perror() call, that gives both the filename and the actual error
reason, so that users get a chance of correcting that.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Mark Brown <broone@kernel.org>
Link: https://lore.kernel.org/r/20210319165334.29213-12-andre.przywara@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
---
 tools/testing/selftests/arm64/mte/mte_common_util.c | 1 +
 1 file changed, 1 insertion(+)

(limited to 'tools')

diff --git a/tools/testing/selftests/arm64/mte/mte_common_util.c b/tools/testing/selftests/arm64/mte/mte_common_util.c
index 040abdca079d..f50ac31920d1 100644
--- a/tools/testing/selftests/arm64/mte/mte_common_util.c
+++ b/tools/testing/selftests/arm64/mte/mte_common_util.c
@@ -337,6 +337,7 @@ int create_temp_file(void)
 	/* Create a file in the tmpfs filesystem */
 	fd = mkstemp(&filename[0]);
 	if (fd == -1) {
+		perror(filename);
 		ksft_print_msg("FAIL: Unable to open temporary file\n");
 		return 0;
 	}
-- 
cgit v1.2.3


From 314bcbf09f147cfb069bc22207215b6b0b7da510 Mon Sep 17 00:00:00 2001
From: Mark Brown
Date: Tue, 9 Mar 2021 19:37:31 +0000
Subject: kselftest: arm64: Add BTI tests

Add some tests that verify that BTI functions correctly for static binaries
built with and without BTI support, verifying that SIGILL is generated when
expected and is not generated in other situations.

Since BTI support is still being rolled out in distributions these tests
are built entirely free standing, no libc support is used at all so none
of the standard helper functions for kselftest can be used and we open
code everything. This also means we aren't testing the kernel support for
the dynamic linker, though the test program can be readily adapted for
that once it becomes something that we can reliably build and run.

These tests were originally written by Dave Martin, I've adapted them for
kselftest, mainly around the build system and the output format.

Signed-off-by: Mark Brown <broonie@kernel.org>
Cc: Dave Martin <Dave.Martin@arm.com>
Link: https://lore.kernel.org/r/20210309193731.57247-1-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
---
 tools/testing/selftests/arm64/Makefile           |   2 +-
 tools/testing/selftests/arm64/bti/.gitignore     |   2 +
 tools/testing/selftests/arm64/bti/Makefile       |  61 ++++++
 tools/testing/selftests/arm64/bti/assembler.h    |  80 ++++++++
 tools/testing/selftests/arm64/bti/btitest.h      |  23 +++
 tools/testing/selftests/arm64/bti/compiler.h     |  21 ++
 tools/testing/selftests/arm64/bti/gen/.gitignore |   2 +
 tools/testing/selftests/arm64/bti/signal.c       |  37 ++++
 tools/testing/selftests/arm64/bti/signal.h       |  21 ++
 tools/testing/selftests/arm64/bti/start.S        |  14 ++
 tools/testing/selftests/arm64/bti/syscall.S      |  23 +++
 tools/testing/selftests/arm64/bti/system.c       |  22 +++
 tools/testing/selftests/arm64/bti/system.h       |  28 +++
 tools/testing/selftests/arm64/bti/test.c         | 234 +++++++++++++++++++++++
 tools/testing/selftests/arm64/bti/teststubs.S    |  39 ++++
 tools/testing/selftests/arm64/bti/trampoline.S   |  29 +++
 16 files changed, 637 insertions(+), 1 deletion(-)
 create mode 100644 tools/testing/selftests/arm64/bti/.gitignore
 create mode 100644 tools/testing/selftests/arm64/bti/Makefile
 create mode 100644 tools/testing/selftests/arm64/bti/assembler.h
 create mode 100644 tools/testing/selftests/arm64/bti/btitest.h
 create mode 100644 tools/testing/selftests/arm64/bti/compiler.h
 create mode 100644 tools/testing/selftests/arm64/bti/gen/.gitignore
 create mode 100644 tools/testing/selftests/arm64/bti/signal.c
 create mode 100644 tools/testing/selftests/arm64/bti/signal.h
 create mode 100644 tools/testing/selftests/arm64/bti/start.S
 create mode 100644 tools/testing/selftests/arm64/bti/syscall.S
 create mode 100644 tools/testing/selftests/arm64/bti/system.c
 create mode 100644 tools/testing/selftests/arm64/bti/system.h
 create mode 100644 tools/testing/selftests/arm64/bti/test.c
 create mode 100644 tools/testing/selftests/arm64/bti/teststubs.S
 create mode 100644 tools/testing/selftests/arm64/bti/trampoline.S

(limited to 'tools')

diff --git a/tools/testing/selftests/arm64/Makefile b/tools/testing/selftests/arm64/Makefile
index 2c9d012797a7..ced910fb4019 100644
--- a/tools/testing/selftests/arm64/Makefile
+++ b/tools/testing/selftests/arm64/Makefile
@@ -4,7 +4,7 @@
 ARCH ?= $(shell uname -m 2>/dev/null || echo not)
 
 ifneq (,$(filter $(ARCH),aarch64 arm64))
-ARM64_SUBTARGETS ?= tags signal pauth fp mte
+ARM64_SUBTARGETS ?= tags signal pauth fp mte bti
 else
 ARM64_SUBTARGETS :=
 endif
diff --git a/tools/testing/selftests/arm64/bti/.gitignore b/tools/testing/selftests/arm64/bti/.gitignore
new file mode 100644
index 000000000000..73869fabada4
--- /dev/null
+++ b/tools/testing/selftests/arm64/bti/.gitignore
@@ -0,0 +1,2 @@
+btitest
+nobtitest
diff --git a/tools/testing/selftests/arm64/bti/Makefile b/tools/testing/selftests/arm64/bti/Makefile
new file mode 100644
index 000000000000..73e013c082a6
--- /dev/null
+++ b/tools/testing/selftests/arm64/bti/Makefile
@@ -0,0 +1,61 @@
+# SPDX-License-Identifier: GPL-2.0
+
+TEST_GEN_PROGS := btitest nobtitest
+
+PROGS := $(patsubst %,gen/%,$(TEST_GEN_PROGS))
+
+# These tests are built as freestanding binaries since otherwise BTI
+# support in ld.so is required which is not currently widespread; when
+# it is available it will still be useful to test this separately as the
+# cases for statically linked and dynamically lined binaries are
+# slightly different.
+
+CFLAGS_NOBTI = -DBTI=0
+CFLAGS_BTI = -mbranch-protection=standard -DBTI=1
+
+CFLAGS_COMMON = -ffreestanding -Wall -Wextra $(CFLAGS)
+
+BTI_CC_COMMAND = $(CC) $(CFLAGS_BTI) $(CFLAGS_COMMON) -c -o $@ $<
+NOBTI_CC_COMMAND = $(CC) $(CFLAGS_NOBTI) $(CFLAGS_COMMON) -c -o $@ $<
+
+%-bti.o: %.c
+	$(BTI_CC_COMMAND)
+
+%-bti.o: %.S
+	$(BTI_CC_COMMAND)
+
+%-nobti.o: %.c
+	$(NOBTI_CC_COMMAND)
+
+%-nobti.o: %.S
+	$(NOBTI_CC_COMMAND)
+
+BTI_OBJS =                                      \
+	test-bti.o                           \
+	signal-bti.o                            \
+	start-bti.o                             \
+	syscall-bti.o                           \
+	system-bti.o                            \
+	teststubs-bti.o                         \
+	trampoline-bti.o
+gen/btitest: $(BTI_OBJS)
+	$(CC) $(CFLAGS_BTI) $(CFLAGS_COMMON) -nostdlib -o $@ $^
+
+NOBTI_OBJS =                                    \
+	test-nobti.o                         \
+	signal-nobti.o                          \
+	start-nobti.o                           \
+	syscall-nobti.o                         \
+	system-nobti.o                          \
+	teststubs-nobti.o                       \
+	trampoline-nobti.o
+gen/nobtitest: $(NOBTI_OBJS)
+	$(CC) $(CFLAGS_BTI) $(CFLAGS_COMMON) -nostdlib -o $@ $^
+
+# Including KSFT lib.mk here will also mangle the TEST_GEN_PROGS list
+# to account for any OUTPUT target-dirs optionally provided by
+# the toplevel makefile
+include ../../lib.mk
+
+$(TEST_GEN_PROGS): $(PROGS)
+	cp $(PROGS) $(OUTPUT)/
diff --git a/tools/testing/selftests/arm64/bti/assembler.h b/tools/testing/selftests/arm64/bti/assembler.h
new file mode 100644
index 000000000000..04e7b72880ef
--- /dev/null
+++ b/tools/testing/selftests/arm64/bti/assembler.h
@@ -0,0 +1,80 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2019  Arm Limited
+ * Original author: Dave Martin <Dave.Martin@arm.com>
+ */
+
+#ifndef ASSEMBLER_H
+#define ASSEMBLER_H
+
+#define NT_GNU_PROPERTY_TYPE_0	5
+#define GNU_PROPERTY_AARCH64_FEATURE_1_AND	0xc0000000
+
+/* Bits for GNU_PROPERTY_AARCH64_FEATURE_1_BTI */
+#define GNU_PROPERTY_AARCH64_FEATURE_1_BTI	(1U << 0)
+#define GNU_PROPERTY_AARCH64_FEATURE_1_PAC	(1U << 1)
+
+
+.macro startfn name:req
+	.globl \name
+\name:
+	.macro endfn
+		.size \name, . - \name
+		.type \name, @function
+		.purgem endfn
+	.endm
+.endm
+
+.macro emit_aarch64_feature_1_and
+	.pushsection .note.gnu.property, "a"
+	.align	3
+	.long	2f - 1f
+	.long	6f - 3f
+	.long	NT_GNU_PROPERTY_TYPE_0
+1:	.string	"GNU"
+2:
+	.align	3
+3:	.long	GNU_PROPERTY_AARCH64_FEATURE_1_AND
+	.long	5f - 4f
+4:
+#if BTI
+	.long	GNU_PROPERTY_AARCH64_FEATURE_1_PAC | \
+		GNU_PROPERTY_AARCH64_FEATURE_1_BTI
+#else
+	.long	0
+#endif
+5:
+	.align	3
+6:
+	.popsection
+.endm
+
+.macro paciasp
+	hint	0x19
+.endm
+
+.macro autiasp
+	hint	0x1d
+.endm
+
+.macro __bti_
+	hint	0x20
+.endm
+
+.macro __bti_c
+	hint	0x22
+.endm
+
+.macro __bti_j
+	hint	0x24
+.endm
+
+.macro __bti_jc
+	hint	0x26
+.endm
+
+.macro bti what=
+	__bti_\what
+.endm
+
+#endif /* ! ASSEMBLER_H */
diff --git a/tools/testing/selftests/arm64/bti/btitest.h b/tools/testing/selftests/arm64/bti/btitest.h
new file mode 100644
index 000000000000..2aff9b10336e
--- /dev/null
+++ b/tools/testing/selftests/arm64/bti/btitest.h
@@ -0,0 +1,23 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2019  Arm Limited
+ * Original author: Dave Martin <Dave.Martin@arm.com>
+ */
+
+#ifndef BTITEST_H
+#define BTITEST_H
+
+/* Trampolines for calling the test stubs: */
+void call_using_br_x0(void (*)(void));
+void call_using_br_x16(void (*)(void));
+void call_using_blr(void (*)(void));
+
+/* Test stubs: */
+void nohint_func(void);
+void bti_none_func(void);
+void bti_c_func(void);
+void bti_j_func(void);
+void bti_jc_func(void);
+void paciasp_func(void);
+
+#endif /* !BTITEST_H */
diff --git a/tools/testing/selftests/arm64/bti/compiler.h b/tools/testing/selftests/arm64/bti/compiler.h
new file mode 100644
index 000000000000..ebb6204f447a
--- /dev/null
+++ b/tools/testing/selftests/arm64/bti/compiler.h
@@ -0,0 +1,21 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2019  Arm Limited
+ * Original author: Dave Martin <Dave.Martin@arm.com>
+ */
+
+#ifndef COMPILER_H
+#define COMPILER_H
+
+#define __always_unused __attribute__((__unused__))
+#define __noreturn __attribute__((__noreturn__))
+#define __unreachable() __builtin_unreachable()
+
+/* curse(e) has value e, but the compiler cannot assume so */
+#define curse(e) ({				\
+	__typeof__(e) __curse_e = (e);		\
+	asm ("" : "+r" (__curse_e));		\
+	__curse_e;				\
+})
+
+#endif /* ! COMPILER_H */
diff --git a/tools/testing/selftests/arm64/bti/gen/.gitignore b/tools/testing/selftests/arm64/bti/gen/.gitignore
new file mode 100644
index 000000000000..73869fabada4
--- /dev/null
+++ b/tools/testing/selftests/arm64/bti/gen/.gitignore
@@ -0,0 +1,2 @@
+btitest
+nobtitest
diff --git a/tools/testing/selftests/arm64/bti/signal.c b/tools/testing/selftests/arm64/bti/signal.c
new file mode 100644
index 000000000000..f3fd29b91141
--- /dev/null
+++ b/tools/testing/selftests/arm64/bti/signal.c
@@ -0,0 +1,37 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2019  Arm Limited
+ * Original author: Dave Martin <Dave.Martin@arm.com>
+ */
+
+#include "system.h"
+#include "signal.h"
+
+int sigemptyset(sigset_t *s)
+{
+	unsigned int i;
+
+	for (i = 0; i < _NSIG_WORDS; ++i)
+		s->sig[i] = 0;
+
+	return 0;
+}
+
+int sigaddset(sigset_t *s, int n)
+{
+	if (n < 1 || n > _NSIG)
+		return -EINVAL;
+
+	s->sig[(n - 1) / _NSIG_BPW] |= 1UL << (n - 1) % _NSIG_BPW;
+	return 0;
+}
+
+int sigaction(int n, struct sigaction *sa, const struct sigaction *old)
+{
+	return syscall(__NR_rt_sigaction, n, sa, old, sizeof(sa->sa_mask));
+}
+
+int sigprocmask(int how, const sigset_t *mask, sigset_t *old)
+{
+	return syscall(__NR_rt_sigprocmask, how, mask, old, sizeof(*mask));
+}
diff --git a/tools/testing/selftests/arm64/bti/signal.h b/tools/testing/selftests/arm64/bti/signal.h
new file mode 100644
index 000000000000..103457dc880e
--- /dev/null
+++ b/tools/testing/selftests/arm64/bti/signal.h
@@ -0,0 +1,21 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2019  Arm Limited
+ * Original author: Dave Martin <Dave.Martin@arm.com>
+ */
+
+#ifndef SIGNAL_H
+#define SIGNAL_H
+
+#include <linux/signal.h>
+
+#include "system.h"
+
+typedef __sighandler_t sighandler_t;
+
+int sigemptyset(sigset_t *s);
+int sigaddset(sigset_t *s, int n);
+int sigaction(int n, struct sigaction *sa, const struct sigaction *old);
+int sigprocmask(int how, const sigset_t *mask, sigset_t *old);
+
+#endif /* ! SIGNAL_H */
diff --git a/tools/testing/selftests/arm64/bti/start.S b/tools/testing/selftests/arm64/bti/start.S
new file mode 100644
index 000000000000..831f952e0572
--- /dev/null
+++ b/tools/testing/selftests/arm64/bti/start.S
@@ -0,0 +1,14 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2019  Arm Limited
+ * Original author: Dave Martin <Dave.Martin@arm.com>
+ */
+
+#include "assembler.h"
+
+startfn _start
+	mov	x0, sp
+	b	start
+endfn
+
+emit_aarch64_feature_1_and
diff --git a/tools/testing/selftests/arm64/bti/syscall.S b/tools/testing/selftests/arm64/bti/syscall.S
new file mode 100644
index 000000000000..8dde8b6f3db1
--- /dev/null
+++ b/tools/testing/selftests/arm64/bti/syscall.S
@@ -0,0 +1,23 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2019  Arm Limited
+ * Original author: Dave Martin <Dave.Martin@arm.com>
+ */
+
+#include "assembler.h"
+
+startfn syscall
+	bti	c
+	mov	w8, w0
+	mov	x0, x1
+	mov	x1, x2
+	mov	x2, x3
+	mov	x3, x4
+	mov	x4, x5
+	mov	x5, x6
+	mov	x6, x7
+	svc	#0
+	ret
+endfn
+
+emit_aarch64_feature_1_and
diff --git a/tools/testing/selftests/arm64/bti/system.c b/tools/testing/selftests/arm64/bti/system.c
new file mode 100644
index 000000000000..6385d8d4973b
--- /dev/null
+++ b/tools/testing/selftests/arm64/bti/system.c
@@ -0,0 +1,22 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2019  Arm Limited
+ * Original author: Dave Martin <Dave.Martin@arm.com>
+ */
+
+#include "system.h"
+
+#include <asm/unistd.h>
+
+#include "compiler.h"
+
+void __noreturn exit(int n)
+{
+	syscall(__NR_exit, n);
+	__unreachable();
+}
+
+ssize_t write(int fd, const void *buf, size_t size)
+{
+	return syscall(__NR_write, fd, buf, size);
+}
diff --git a/tools/testing/selftests/arm64/bti/system.h b/tools/testing/selftests/arm64/bti/system.h
new file mode 100644
index 000000000000..aca118589705
--- /dev/null
+++ b/tools/testing/selftests/arm64/bti/system.h
@@ -0,0 +1,28 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2019  Arm Limited
+ * Original author: Dave Martin <Dave.Martin@arm.com>
+ */
+
+#ifndef SYSTEM_H
+#define SYSTEM_H
+
+#include <linux/types.h>
+#include <linux/stddef.h>
+
+typedef __kernel_size_t size_t;
+typedef __kernel_ssize_t ssize_t;
+
+#include <linux/errno.h>
+#include <asm/hwcap.h>
+#include <asm/ptrace.h>
+#include <asm/unistd.h>
+
+#include "compiler.h"
+
+long syscall(int nr, ...);
+
+void __noreturn exit(int n);
+ssize_t write(int fd, const void *buf, size_t size);
+
+#endif /* ! SYSTEM_H */
diff --git a/tools/testing/selftests/arm64/bti/test.c b/tools/testing/selftests/arm64/bti/test.c
new file mode 100644
index 000000000000..656b04976ccc
--- /dev/null
+++ b/tools/testing/selftests/arm64/bti/test.c
@@ -0,0 +1,234 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2019,2021  Arm Limited
+ * Original author: Dave Martin <Dave.Martin@arm.com>
+ */
+
+#include "system.h"
+
+#include <linux/errno.h>
+#include <linux/auxvec.h>
+#include <linux/signal.h>
+#include <asm/sigcontext.h>
+#include <asm/ucontext.h>
+
+typedef struct ucontext ucontext_t;
+
+#include "btitest.h"
+#include "compiler.h"
+#include "signal.h"
+
+#define EXPECTED_TESTS 18
+
+static volatile unsigned int test_num = 1;
+static unsigned int test_passed;
+static unsigned int test_failed;
+static unsigned int test_skipped;
+
+static void fdputs(int fd, const char *str)
+{
+	size_t len = 0;
+	const char *p = str;
+
+	while (*p++)
+		++len;
+
+	write(fd, str, len);
+}
+
+static void putstr(const char *str)
+{
+	fdputs(1, str);
+}
+
+static void putnum(unsigned int num)
+{
+	char c;
+
+	if (num / 10)
+		putnum(num / 10);
+
+	c = '0' + (num % 10);
+	write(1, &c, 1);
+}
+
+#define puttestname(test_name, trampoline_name) do {	\
+	putstr(test_name);				\
+	putstr("/");					\
+	putstr(trampoline_name);			\
+} while (0)
+
+void print_summary(void)
+{
+	putstr("# Totals: pass:");
+	putnum(test_passed);
+	putstr(" fail:");
+	putnum(test_failed);
+	putstr(" xfail:0 xpass:0 skip:");
+	putnum(test_skipped);
+	putstr(" error:0\n");
+}
+
+static const char *volatile current_test_name;
+static const char *volatile current_trampoline_name;
+static volatile int sigill_expected, sigill_received;
+
+static void handler(int n, siginfo_t *si __always_unused,
+		    void *uc_ __always_unused)
+{
+	ucontext_t *uc = uc_;
+
+	putstr("# \t[SIGILL in ");
+	puttestname(current_test_name, current_trampoline_name);
+	putstr(", BTYPE=");
+	write(1, &"00011011"[((uc->uc_mcontext.pstate & PSR_BTYPE_MASK)
+			      >> PSR_BTYPE_SHIFT) * 2], 2);
+	if (!sigill_expected) {
+		putstr("]\n");
+		putstr("not ok ");
+		putnum(test_num);
+		putstr(" ");
+		puttestname(current_test_name, current_trampoline_name);
+		putstr("(unexpected SIGILL)\n");
+		print_summary();
+		exit(128 + n);
+	}
+
+	putstr(" (expected)]\n");
+	sigill_received = 1;
+	/* zap BTYPE so that resuming the faulting code will work */
+	uc->uc_mcontext.pstate &= ~PSR_BTYPE_MASK;
+}
+
+static int skip_all;
+
+static void __do_test(void (*trampoline)(void (*)(void)),
+		      void (*fn)(void),
+		      const char *trampoline_name,
+		      const char *name,
+		      int expect_sigill)
+{
+	if (skip_all) {
+		test_skipped++;
+		putstr("ok ");
+		putnum(test_num);
+		putstr(" ");
+		puttestname(name, trampoline_name);
+		putstr(" # SKIP\n");
+
+		return;
+	}
+
+	/* Branch Target exceptions should only happen in BTI binaries: */
+	if (!BTI)
+		expect_sigill = 0;
+
+	sigill_expected = expect_sigill;
+	sigill_received = 0;
+	current_test_name = name;
+	current_trampoline_name = trampoline_name;
+
+	trampoline(fn);
+
+	if (expect_sigill && !sigill_received) {
+		putstr("not ok ");
+		test_failed++;
+	} else {
+		putstr("ok ");
+		test_passed++;
+	}
+	putnum(test_num++);
+	putstr(" ");
+	puttestname(name, trampoline_name);
+	putstr("\n");
+}
+
+#define do_test(expect_sigill_br_x0,					\
+		expect_sigill_br_x16,					\
+		expect_sigill_blr,					\
+		name)							\
+do {									\
+	__do_test(call_using_br_x0, name, "call_using_br_x0", #name,	\
+		  expect_sigill_br_x0);					\
+	__do_test(call_using_br_x16, name, "call_using_br_x16", #name,	\
+		  expect_sigill_br_x16);				\
+	__do_test(call_using_blr, name, "call_using_blr", #name,	\
+		  expect_sigill_blr);					\
+} while (0)
+
+void start(int *argcp)
+{
+	struct sigaction sa;
+	void *const *p;
+	const struct auxv_entry {
+		unsigned long type;
+		unsigned long val;
+	} *auxv;
+	unsigned long hwcap = 0, hwcap2 = 0;
+
+	putstr("TAP version 13\n");
+	putstr("1..");
+	putnum(EXPECTED_TESTS);
+	putstr("\n");
+
+	/* Gross hack for finding AT_HWCAP2 from the initial process stack: */
+	p = (void *const *)argcp + 1 + *argcp + 1; /* start of environment */
+	/* step over environment */
+	while (*p++)
+		;
+	for (auxv = (const struct auxv_entry *)p; auxv->type != AT_NULL; ++auxv) {
+		switch (auxv->type) {
+		case AT_HWCAP:
+			hwcap = auxv->val;
+			break;
+		case AT_HWCAP2:
+			hwcap2 = auxv->val;
+			break;
+		default:
+			break;
+		}
+	}
+
+	if (hwcap & HWCAP_PACA)
+		putstr("# HWCAP_PACA present\n");
+	else
+		putstr("# HWCAP_PACA not present\n");
+
+	if (hwcap2 & HWCAP2_BTI) {
+		putstr("# HWCAP2_BTI present\n");
+		if (!(hwcap & HWCAP_PACA))
+			putstr("# Bad hardware?  Expect problems.\n");
+	} else {
+		putstr("# HWCAP2_BTI not present\n");
+		skip_all = 1;
+	}
+
+	putstr("# Test binary");
+	if (!BTI)
+		putstr(" not");
+	putstr(" built for BTI\n");
+
+	sa.sa_handler = (sighandler_t)(void *)handler;
+	sa.sa_flags = SA_SIGINFO;
+	sigemptyset(&sa.sa_mask);
+	sigaction(SIGILL, &sa, NULL);
+	sigaddset(&sa.sa_mask, SIGILL);
+	sigprocmask(SIG_UNBLOCK, &sa.sa_mask, NULL);
+
+	do_test(1, 1, 1, nohint_func);
+	do_test(1, 1, 1, bti_none_func);
+	do_test(1, 0, 0, bti_c_func);
+	do_test(0, 0, 1, bti_j_func);
+	do_test(0, 0, 0, bti_jc_func);
+	do_test(1, 0, 0, paciasp_func);
+
+	print_summary();
+
+	if (test_num - 1 != EXPECTED_TESTS)
+		putstr("# WARNING - EXPECTED TEST COUNT WRONG\n");
+
+	if (test_failed)
+		exit(1);
+	else
+		exit(0);
+}
diff --git a/tools/testing/selftests/arm64/bti/teststubs.S b/tools/testing/selftests/arm64/bti/teststubs.S
new file mode 100644
index 000000000000..b62c8c35f67e
--- /dev/null
+++ b/tools/testing/selftests/arm64/bti/teststubs.S
@@ -0,0 +1,39 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2019  Arm Limited
+ * Original author: Dave Martin <Dave.Martin@arm.com>
+ */
+
+#include "assembler.h"
+
+startfn bti_none_func
+	bti
+	ret
+endfn
+
+startfn bti_c_func
+	bti	c
+	ret
+endfn
+
+startfn bti_j_func
+	bti	j
+	ret
+endfn
+
+startfn bti_jc_func
+	bti	jc
+	ret
+endfn
+
+startfn paciasp_func
+	paciasp
+	autiasp
+	ret
+endfn
+
+startfn nohint_func
+	ret
+endfn
+
+emit_aarch64_feature_1_and
diff --git a/tools/testing/selftests/arm64/bti/trampoline.S b/tools/testing/selftests/arm64/bti/trampoline.S
new file mode 100644
index 000000000000..09beb3f361f1
--- /dev/null
+++ b/tools/testing/selftests/arm64/bti/trampoline.S
@@ -0,0 +1,29 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2019  Arm Limited
+ * Original author: Dave Martin <Dave.Martin@arm.com>
+ */
+
+#include "assembler.h"
+
+startfn call_using_br_x0
+	bti	c
+	br	x0
+endfn
+
+startfn call_using_br_x16
+	bti	c
+	mov	x16, x0
+	br	x16
+endfn
+
+startfn call_using_blr
+	paciasp
+	stp	x29, x30, [sp, #-16]!
+	blr	x0
+	ldp	x29, x30, [sp], #16
+	autiasp
+	ret
+endfn
+
+emit_aarch64_feature_1_and
-- 
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