This patch is a part of a series that extends arm64 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.
Co-developed-by: Catalin Marinas catalin.marinas@arm.com Signed-off-by: Andrey Konovalov andreyknvl@google.com --- tools/testing/selftests/arm64/.gitignore | 2 + tools/testing/selftests/arm64/Makefile | 22 +++++++ .../testing/selftests/arm64/run_tags_test.sh | 12 ++++ tools/testing/selftests/arm64/tags_lib.c | 62 +++++++++++++++++++ tools/testing/selftests/arm64/tags_test.c | 18 ++++++ 5 files changed, 116 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_lib.c 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..9b6a568de17f --- /dev/null +++ b/tools/testing/selftests/arm64/.gitignore @@ -0,0 +1,2 @@ +tags_test +tags_lib.so diff --git a/tools/testing/selftests/arm64/Makefile b/tools/testing/selftests/arm64/Makefile new file mode 100644 index 000000000000..9dee18727923 --- /dev/null +++ b/tools/testing/selftests/arm64/Makefile @@ -0,0 +1,22 @@ +# SPDX-License-Identifier: GPL-2.0 + +include ../lib.mk + +# 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_CUSTOM_PROGS := $(OUTPUT)/tags_test + +$(OUTPUT)/tags_test: tags_test.c $(OUTPUT)/tags_lib.so + $(CC) -o $@ $(CFLAGS) $(LDFLAGS) $< + +$(OUTPUT)/tags_lib.so: tags_lib.c + $(CC) -o $@ -shared $(CFLAGS) $(LDFLAGS) $^ + +TEST_PROGS := run_tags_test.sh + +all: $(TEST_CUSTOM_PROGS) + +endif 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..2bbe0cd4220b --- /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 "--------------------" +LD_PRELOAD=./tags_lib.so ./tags_test +if [ $? -ne 0 ]; then + echo "[FAIL]" +else + echo "[PASS]" +fi diff --git a/tools/testing/selftests/arm64/tags_lib.c b/tools/testing/selftests/arm64/tags_lib.c new file mode 100644 index 000000000000..55f64fc1aae6 --- /dev/null +++ b/tools/testing/selftests/arm64/tags_lib.c @@ -0,0 +1,62 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include <stdlib.h> +#include <sys/prctl.h> + +#define TAG_SHIFT (56) +#define TAG_MASK (0xffUL << TAG_SHIFT) + +#define PR_SET_TAGGED_ADDR_CTRL 55 +#define PR_GET_TAGGED_ADDR_CTRL 56 +#define PR_TAGGED_ADDR_ENABLE (1UL << 0) + +void *__libc_malloc(size_t size); +void __libc_free(void *ptr); +void *__libc_realloc(void *ptr, size_t size); +void *__libc_calloc(size_t nmemb, size_t size); + +static void *tag_ptr(void *ptr) +{ + static int tagged_addr_err = 1; + unsigned long tag = 0; + + /* + * Note that this code is racy. We only use it as a part of a single + * threaded test application. Beware of using in multithreaded ones. + */ + if (tagged_addr_err == 1) + tagged_addr_err = prctl(PR_SET_TAGGED_ADDR_CTRL, + PR_TAGGED_ADDR_ENABLE, 0, 0, 0); + + if (!ptr) + return ptr; + if (!tagged_addr_err) + tag = rand() & 0xff; + + return (void *)((unsigned long)ptr | (tag << TAG_SHIFT)); +} + +static void *untag_ptr(void *ptr) +{ + return (void *)((unsigned long)ptr & ~TAG_MASK); +} + +void *malloc(size_t size) +{ + return tag_ptr(__libc_malloc(size)); +} + +void free(void *ptr) +{ + __libc_free(untag_ptr(ptr)); +} + +void *realloc(void *ptr, size_t size) +{ + return tag_ptr(__libc_realloc(untag_ptr(ptr), size)); +} + +void *calloc(size_t nmemb, size_t size) +{ + return tag_ptr(__libc_calloc(nmemb, size)); +} diff --git a/tools/testing/selftests/arm64/tags_test.c b/tools/testing/selftests/arm64/tags_test.c new file mode 100644 index 000000000000..263b302874ed --- /dev/null +++ b/tools/testing/selftests/arm64/tags_test.c @@ -0,0 +1,18 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include <stdio.h> +#include <stdlib.h> +#include <unistd.h> +#include <stdint.h> +#include <sys/utsname.h> + +int main(void) +{ + struct utsname *ptr; + int err; + + ptr = (struct utsname *)malloc(sizeof(*ptr)); + err = uname(ptr); + free(ptr); + return err; +}