Subject: Re: [PATCH v3 03/11] kselftest: arm64: mangle_pstate_invalid_daif_bits

From: Dave Martin <[email-masked]>
Date: Tue, 13 Aug 2019 17:24:34 +0100

On Fri, Aug 02, 2019 at 06:02:52PM +0100, Cristian Marussi wrote:
> Added a simple mangle testcase which messes with the ucontext_t

Strange past tense?  How about "Add"?

> from within the sig_handler, trying to set PSTATE DAIF bits to an

"signal handler"?

> invalid value (masking everything). Expects SIGSEGV on test PASS.
> 
> Signed-off-by: Cristian Marussi <[email-masked]>
> ---
>  .../arm64/signal/testcases/.gitignore         |  1 +
>  .../mangle_pstate_invalid_daif_bits.c         | 28 +++++++++++++++++++
>  2 files changed, 29 insertions(+)
>  create mode 100644 tools/testing/selftests/arm64/signal/testcases/mangle_pstate_invalid_daif_bits.c
> 
> diff --git a/tools/testing/selftests/arm64/signal/testcases/.gitignore b/tools/testing/selftests/arm64/signal/testcases/.gitignore
> index 8651272e3cfc..8a0a29f0cc2a 100644
> --- a/tools/testing/selftests/arm64/signal/testcases/.gitignore
> +++ b/tools/testing/selftests/arm64/signal/testcases/.gitignore
> @@ -1 +1,2 @@
>  mangle_pstate_invalid_compat_toggle
> +mangle_pstate_invalid_daif_bits
> diff --git a/tools/testing/selftests/arm64/signal/testcases/mangle_pstate_invalid_daif_bits.c b/tools/testing/selftests/arm64/signal/testcases/mangle_pstate_invalid_daif_bits.c
> new file mode 100644
> index 000000000000..af899d4bb655
> --- /dev/null
> +++ b/tools/testing/selftests/arm64/signal/testcases/mangle_pstate_invalid_daif_bits.c
> @@ -0,0 +1,28 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/* Copyright (C) 2019 ARM Limited */
> +
> +#include "test_signals_utils.h"
> +#include "testcases.h"
> +
> +static int mangle_invalid_pstate_run(struct tdescr *td, siginfo_t *si,
> +				     ucontext_t *uc)
> +{
> +	ASSERT_GOOD_CONTEXT(uc);
> +
> +	/*
> +	 * This config should trigger a SIGSEGV by Kernel when it checks
> +	 * the sigframe consistency in valid_user_regs() routine.
> +	 */
> +	uc->uc_mcontext.pstate |= PSR_D_BIT | PSR_A_BIT | PSR_I_BIT | PSR_F_BIT;
> +
> +	return 1;
> +}

Hmmm, there was a lot of common framework code, but it seems like a good
investment if adding a new test is as simple as this :)

[...]

Cheers
---Dave

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