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

Catalin Marinas
2019-06-24T17:38:06Z

On Mon, Jun 24, 2019 at 04:33:00PM +0200, Andrey Konovalov wrote:
> --- /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;

Nitpick: with the latest prctl() patch, you can skip the last three
arguments as they are ignored.

Either way:

Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>