On Thu, Jun 13, 2019 at 12:13:30PM +0100, Cristian Marussi wrote:
> Added a simple mangle testcase which messes with the ucontext_t
> from within the sig_handler, trying to toggle PSTATE SSBS bit.
> Expect SIGILL if SSBS feature unsupported or that the value set in
> PSTATE.SSBS is preserved on test PASS.
>
> Signed-off-by: Cristian Marussi <cristian.marussi@xxxxxxx>
> ---
> .../arm64/signal/testcases/.gitignore | 1 +
> .../testcases/mangle_pstate_ssbs_regs.c | 41 +++++++++++++++++++
> 2 files changed, 42 insertions(+)
> create mode 100644 tools/testing/selftests/arm64/signal/testcases/mangle_pstate_ssbs_regs.c
>
> diff --git a/tools/testing/selftests/arm64/signal/testcases/.gitignore b/tools/testing/selftests/arm64/signal/testcases/.gitignore
> index e7a1d998b650..c2972c3f33ca 100644
> --- a/tools/testing/selftests/arm64/signal/testcases/.gitignore
> +++ b/tools/testing/selftests/arm64/signal/testcases/.gitignore
> @@ -5,3 +5,4 @@ mangle_pstate_invalid_state_toggle
> mangle_pstate_invalid_mode_el1
> mangle_pstate_invalid_mode_el2
> mangle_pstate_invalid_mode_el3
> +mangle_pstate_ssbs_regs
> diff --git a/tools/testing/selftests/arm64/signal/testcases/mangle_pstate_ssbs_regs.c b/tools/testing/selftests/arm64/signal/testcases/mangle_pstate_ssbs_regs.c
> new file mode 100644
> index 000000000000..d997ebf742d9
> --- /dev/null
> +++ b/tools/testing/selftests/arm64/signal/testcases/mangle_pstate_ssbs_regs.c
> @@ -0,0 +1,41 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/* Copyright (C) 2019 ARM Limited */
> +
> +#include "test_signals_utils.h"
> +#include "testcases.h"
> +
> +static int mangle_invalid_pstate_ssbs_run(struct tdescr *td,
> + siginfo_t *si, ucontext_t *uc)
> +{
> + ASSERT_GOOD_CONTEXT(uc);
> +
> + /* toggle bit value */
> + uc->uc_mcontext.pstate ^= PSR_SSBS_BIT;
> + /* Save after mangling...it should be preserved */
> + td->saved_uc = *uc;
> +
> + return 1;
> +}
> +
> +static int pstate_ssbs_bit_checks(struct tdescr *td)
> +{
> + uint64_t val = 0;
> +
> + get_regval(MRS_SSBS_SYSREG, val);
> + /* pass when preserved */
> + td->pass = (!!(val & MRS_SSBS_BIT) ==
> + !!(td->saved_uc.uc_mcontext.pstate & PSR_SSBS_BIT));
Nit: there's a redundant level of ! here, and the outer () are unnecessary:
(!!a == !!b) -> !a == !b
[...]
Can we trigger a second signal after the first returns, to grab the
updated ucontext and check SSBS in there directly?
Checking that the updated value is _also_ visible via MRS remains
useful though, so we should keep that.
Cheers
---Dave
