[PATCH v1 0/4] kselftest/arm64: Miscelaneous MTE test updates

[PATCH v1 0/4] kselftest/arm64: Miscelaneous MTE test updates

[Mark Brown]

This series is just a set of minor tweaks and improvements for the MTE
tests that I did while working on the asymmetric mode support for
userspace which seemed like they might be worth keeping even though the
prctl() for asymmetric mode got removed.

Mark Brown (4):
  kselftest/arm64: Handle more kselftest result codes in MTE helpers
  kselftest/arm64: Log unexpected asynchronous MTE faults
  kselftest/arm64: Refactor parameter checking in mte_switch_mode()
  kselftest/arm64: Add simple test for MTE prctl

 tools/testing/selftests/arm64/mte/.gitignore  |   1 +
 .../testing/selftests/arm64/mte/check_prctl.c | 123 ++++++++++++++++++
 .../selftests/arm64/mte/mte_common_util.c     |  17 ++-
 .../selftests/arm64/mte/mte_common_util.h     |  15 ++-
 4 files changed, 151 insertions(+), 5 deletions(-)
 create mode 100644 tools/testing/selftests/arm64/mte/check_prctl.c


base-commit: dfd42facf1e4ada021b939b4e19c935dcdd55566
-- 
2.30.2

[PATCH v1 1/4] kselftest/arm64: Handle more kselftest result codes in MTE helpers

[Mark Brown]

The MTE selftests have a helper evaluate_test() which translates a return
code into a call to ksft_test_result_*(). Currently this only handles pass
and fail, silently ignoring any other code. Update the helper to support
skipped tests and log any unknown return codes as an error so we get at
least some diagnostic if anything goes wrong.

Signed-off-by: Mark Brown <broonie@kernel.org>
---
 .../testing/selftests/arm64/mte/mte_common_util.h | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/tools/testing/selftests/arm64/mte/mte_common_util.h b/tools/testing/selftests/arm64/mte/mte_common_util.h
index 195a7d1879e6..2d3e71724e55 100644
--- a/tools/testing/selftests/arm64/mte/mte_common_util.h
+++ b/tools/testing/selftests/arm64/mte/mte_common_util.h
@@ -75,10 +75,21 @@ unsigned int mte_get_pstate_tco(void);
 /* Test framework static inline functions/macros */
 static inline void evaluate_test(int err, const char *msg)
 {
-	if (err == KSFT_PASS)
+	switch (err) {
+	case KSFT_PASS:
 		ksft_test_result_pass(msg);
-	else if (err == KSFT_FAIL)
+		break;
+	case KSFT_FAIL:
 		ksft_test_result_fail(msg);
+		break;
+	case KSFT_SKIP:
+		ksft_test_result_skip(msg);
+		break;
+	default:
+		ksft_test_result_error("Unknown return code %d from %s",
+				       err, msg);
+		break;
+	}
 }
 
 static inline int check_allocated_memory(void *ptr, size_t size,
-- 
2.30.2

Re: [PATCH v1 1/4] kselftest/arm64: Handle more kselftest result codes in MTE helpers

[Shuah Khan]

On 3/10/22 7:43 AM, Mark Brown wrote:
> The MTE selftests have a helper evaluate_test() which translates a return
> code into a call to ksft_test_result_*(). Currently this only handles pass
> and fail, silently ignoring any other code. Update the helper to support
> skipped tests and log any unknown return codes as an error so we get at
> least some diagnostic if anything goes wrong.
> 
> Signed-off-by: Mark Brown <broonie@kernel.org>
> ---
>   .../testing/selftests/arm64/mte/mte_common_util.h | 15 +++++++++++++--
>   1 file changed, 13 insertions(+), 2 deletions(-)
> 
> diff --git a/tools/testing/selftests/arm64/mte/mte_common_util.h b/tools/testing/selftests/arm64/mte/mte_common_util.h
> index 195a7d1879e6..2d3e71724e55 100644
> --- a/tools/testing/selftests/arm64/mte/mte_common_util.h
> +++ b/tools/testing/selftests/arm64/mte/mte_common_util.h
> @@ -75,10 +75,21 @@ unsigned int mte_get_pstate_tco(void);
>   /* Test framework static inline functions/macros */
>   static inline void evaluate_test(int err, const char *msg)
>   {
> -	if (err == KSFT_PASS)
> +	switch (err) {
> +	case KSFT_PASS:
>   		ksft_test_result_pass(msg);
> -	else if (err == KSFT_FAIL)
> +		break;
> +	case KSFT_FAIL:
>   		ksft_test_result_fail(msg);
> +		break;
> +	case KSFT_SKIP:
> +		ksft_test_result_skip(msg);
> +		break;
> +	default:
> +		ksft_test_result_error("Unknown return code %d from %s",
> +				       err, msg);
> +		break;
> +	}
>   }
>   
>   static inline int check_allocated_memory(void *ptr, size_t size,
> 

Nice. Thank you for doing this.

Reviewed-by: Shuah Khan <skhan@linuxfoundation.org>

thanks,
-- Shuah

[PATCH v1 2/4] kselftest/arm64: Log unexpected asynchronous MTE faults

[Mark Brown]

Help people figure out problems by printing a diagnostic when we get an
unexpected asynchronous fault.

Signed-off-by: Mark Brown <broonie@kernel.org>
---
 tools/testing/selftests/arm64/mte/mte_common_util.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/tools/testing/selftests/arm64/mte/mte_common_util.c b/tools/testing/selftests/arm64/mte/mte_common_util.c
index 0328a1e08f65..24b0c14203cb 100644
--- a/tools/testing/selftests/arm64/mte/mte_common_util.c
+++ b/tools/testing/selftests/arm64/mte/mte_common_util.c
@@ -37,6 +37,8 @@ void mte_default_handler(int signum, siginfo_t *si, void *uc)
 		if (si->si_code == SEGV_MTEAERR) {
 			if (cur_mte_cxt.trig_si_code == si->si_code)
 				cur_mte_cxt.fault_valid = true;
+			else
+				ksft_print_msg("Got unexpected SEGV_MTEAERR\n");
 			return;
 		}
 		/* Compare the context for precise error */
-- 
2.30.2

Re: [PATCH v1 2/4] kselftest/arm64: Log unexpected asynchronous MTE faults

[Shuah Khan]

On 3/10/22 7:43 AM, Mark Brown wrote:
> Help people figure out problems by printing a diagnostic when we get an
> unexpected asynchronous fault.
> 
> Signed-off-by: Mark Brown <broonie@kernel.org>
> ---
>   tools/testing/selftests/arm64/mte/mte_common_util.c | 2 ++
>   1 file changed, 2 insertions(+)
> 
> diff --git a/tools/testing/selftests/arm64/mte/mte_common_util.c b/tools/testing/selftests/arm64/mte/mte_common_util.c
> index 0328a1e08f65..24b0c14203cb 100644
> --- a/tools/testing/selftests/arm64/mte/mte_common_util.c
> +++ b/tools/testing/selftests/arm64/mte/mte_common_util.c
> @@ -37,6 +37,8 @@ void mte_default_handler(int signum, siginfo_t *si, void *uc)
>   		if (si->si_code == SEGV_MTEAERR) {
>   			if (cur_mte_cxt.trig_si_code == si->si_code)
>   				cur_mte_cxt.fault_valid = true;
> +			else
> +				ksft_print_msg("Got unexpected SEGV_MTEAERR\n");

This is good. Would it make sense to add more info. - I see this in the doc?
Would it make sense to also check si_addr?

- *Asynchronous* - The kernel raises a ``SIGSEGV``, in the offending
   thread, asynchronously following one or multiple tag check faults,
   with ``.si_code = SEGV_MTEAERR`` and ``.si_addr = 0`` (the faulting
   address is unknown).

>   			return;
>   		}
>   		/* Compare the context for precise error */
> 

Looks good to me as such.

Reviewed-by: Shuah Khan <skhan@linuxfoundation.org>

thanks,
-- Shuah

[PATCH v1 3/4] kselftest/arm64: Refactor parameter checking in mte_switch_mode()

[Mark Brown]

Currently we just have a big if statement with a non-specific diagnostic
checking both the mode and the tag. Since we'll need to dynamically check
for asymmetric mode support in the system and to improve debugability split
these checks out.

Signed-off-by: Mark Brown <broonie@kernel.org>
---
 .../testing/selftests/arm64/mte/mte_common_util.c | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/tools/testing/selftests/arm64/mte/mte_common_util.c b/tools/testing/selftests/arm64/mte/mte_common_util.c
index 24b0c14203cb..9b4529ef2b29 100644
--- a/tools/testing/selftests/arm64/mte/mte_common_util.c
+++ b/tools/testing/selftests/arm64/mte/mte_common_util.c
@@ -271,9 +271,18 @@ int mte_switch_mode(int mte_option, unsigned long incl_mask)
 {
 	unsigned long en = 0;
 
-	if (!(mte_option == MTE_SYNC_ERR || mte_option == MTE_ASYNC_ERR ||
-	      mte_option == MTE_NONE_ERR || incl_mask <= MTE_ALLOW_NON_ZERO_TAG)) {
-		ksft_print_msg("FAIL: Invalid mte config option\n");
+	switch (mte_option) {
+	case MTE_NONE_ERR:
+	case MTE_SYNC_ERR:
+	case MTE_ASYNC_ERR:
+		break;
+	default:
+		ksft_print_msg("FAIL: Invalid MTE option %x\n", mte_option);
+		return -EINVAL;
+	}
+
+	if (!(incl_mask <= MTE_ALLOW_NON_ZERO_TAG)) {
+		ksft_print_msg("FAIL: Invalid incl_mask %lx\n", incl_mask);
 		return -EINVAL;
 	}
 	en = PR_TAGGED_ADDR_ENABLE;
-- 
2.30.2

Re: [PATCH v1 3/4] kselftest/arm64: Refactor parameter checking in mte_switch_mode()

[Shuah Khan]

On 3/10/22 7:43 AM, Mark Brown wrote:
> Currently we just have a big if statement with a non-specific diagnostic
> checking both the mode and the tag. Since we'll need to dynamically check
> for asymmetric mode support in the system and to improve debugability split
> these checks out.
> 
> Signed-off-by: Mark Brown <broonie@kernel.org>
> ---
>   .../testing/selftests/arm64/mte/mte_common_util.c | 15 ++++++++++++---
>   1 file changed, 12 insertions(+), 3 deletions(-)
> 
> diff --git a/tools/testing/selftests/arm64/mte/mte_common_util.c b/tools/testing/selftests/arm64/mte/mte_common_util.c
> index 24b0c14203cb..9b4529ef2b29 100644
> --- a/tools/testing/selftests/arm64/mte/mte_common_util.c
> +++ b/tools/testing/selftests/arm64/mte/mte_common_util.c
> @@ -271,9 +271,18 @@ int mte_switch_mode(int mte_option, unsigned long incl_mask)
>   {
>   	unsigned long en = 0;
>   
> -	if (!(mte_option == MTE_SYNC_ERR || mte_option == MTE_ASYNC_ERR ||
> -	      mte_option == MTE_NONE_ERR || incl_mask <= MTE_ALLOW_NON_ZERO_TAG)) {
> -		ksft_print_msg("FAIL: Invalid mte config option\n");
> +	switch (mte_option) {
> +	case MTE_NONE_ERR:
> +	case MTE_SYNC_ERR:
> +	case MTE_ASYNC_ERR:
> +		break;
> +	default:
> +		ksft_print_msg("FAIL: Invalid MTE option %x\n", mte_option);
> +		return -EINVAL;
> +	}
> +
> +	if (!(incl_mask <= MTE_ALLOW_NON_ZERO_TAG)) {
> +		ksft_print_msg("FAIL: Invalid incl_mask %lx\n", incl_mask);
>   		return -EINVAL;
>   	}
>   	en = PR_TAGGED_ADDR_ENABLE;
> 

Looks good to me.

Reviewed-by: Shuah Khan <skhan@linuxfoundation.org>

thanks,
-- Shuah

[PATCH v1 4/4] kselftest/arm64: Add simple test for MTE prctl

[Mark Brown]

The current tests use the prctls for various things but there's no
coverage of the edges of the interface so add some basics. This isn't
hugely useful as it is (it originally had some coverage for the
combinations with asymmetric mode but we removed the prctl() for that)
but it might be a helpful starting point for future work, for example
covering error handling.

Signed-off-by: Mark Brown <broonie@kernel.org>
---
 tools/testing/selftests/arm64/mte/.gitignore  |   1 +
 .../testing/selftests/arm64/mte/check_prctl.c | 123 ++++++++++++++++++
 2 files changed, 124 insertions(+)
 create mode 100644 tools/testing/selftests/arm64/mte/check_prctl.c

diff --git a/tools/testing/selftests/arm64/mte/.gitignore b/tools/testing/selftests/arm64/mte/.gitignore
index d1fe4ddf1669..052d0f9f92b3 100644
--- a/tools/testing/selftests/arm64/mte/.gitignore
+++ b/tools/testing/selftests/arm64/mte/.gitignore
@@ -3,5 +3,6 @@ check_gcr_el1_cswitch
 check_tags_inclusion
 check_child_memory
 check_mmap_options
+check_prctl
 check_ksm_options
 check_user_mem
diff --git a/tools/testing/selftests/arm64/mte/check_prctl.c b/tools/testing/selftests/arm64/mte/check_prctl.c
new file mode 100644
index 000000000000..500aefc5d7cd
--- /dev/null
+++ b/tools/testing/selftests/arm64/mte/check_prctl.c
@@ -0,0 +1,123 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2022 ARM Limited
+
+#include <stdbool.h>
+#include <stdio.h>
+#include <string.h>
+
+#include <sys/auxv.h>
+#include <sys/prctl.h>
+
+#include <asm/hwcap.h>
+
+#include "kselftest.h"
+
+static bool system_has_mte;
+
+static int set_tagged_addr_ctrl(int val)
+{
+	int ret;
+
+	ret = prctl(PR_SET_TAGGED_ADDR_CTRL, val, 0, 0, 0);
+	if (ret < 0)
+		ksft_print_msg("PR_SET_TAGGED_ADDR_CTRL: failed %d %d (%s)\n",
+			       ret, errno, strerror(errno));
+	return ret;
+}
+
+static int get_tagged_addr_ctrl(void)
+{
+	int ret;
+
+	ret = prctl(PR_GET_TAGGED_ADDR_CTRL, 0, 0, 0, 0);
+	if (ret < 0)
+		ksft_print_msg("PR_GET_TAGGED_ADDR_CTRL failed: %d %d (%s)\n",
+			       ret, errno, strerror(errno));
+	return ret;
+}
+
+/*
+ * Read the current mode without having done any configuration, should
+ * run first.
+ */
+void check_basic_read(void)
+{
+	int ret;
+
+	ret = get_tagged_addr_ctrl();
+	if (ret < 0) {
+		ksft_test_result_fail("check_basic_read\n");
+		return;
+	}
+
+	if (ret & PR_MTE_TCF_SYNC)
+		ksft_print_msg("SYNC enabled\n");
+	if (ret & PR_MTE_TCF_ASYNC)
+		ksft_print_msg("ASYNC enabled\n");
+
+	/* Any configuration is valid */
+	ksft_test_result_pass("check_basic_read\n");
+}
+
+/*
+ * Attempt to set a specified combination of modes.
+ */
+void set_mode_test(const char *name, int hwcap2, int mask)
+{
+	int ret;
+
+	if ((getauxval(AT_HWCAP2) & hwcap2) != hwcap2) {
+		ksft_test_result_skip("%s\n", name);
+		return;
+	}
+
+	ret = set_tagged_addr_ctrl(mask);
+	if (ret < 0) {
+		ksft_test_result_fail("%s\n", name);
+		return;
+	}
+
+	ret = get_tagged_addr_ctrl();
+	if (ret < 0) {
+		ksft_test_result_fail("%s\n", name);
+		return;
+	}
+
+	if ((ret & PR_MTE_TCF_MASK) == mask) {
+		ksft_test_result_pass("%s\n", name);
+	} else {
+		ksft_print_msg("Got %x, expected %x\n",
+			       (ret & PR_MTE_TCF_MASK), mask);
+		ksft_test_result_fail("%s\n", name);
+	}
+}
+
+struct mte_mode {
+	int mask;
+	int hwcap2;
+	const char *name;
+} mte_modes[] = {
+	{ PR_MTE_TCF_NONE,  0,          "NONE"  },
+	{ PR_MTE_TCF_SYNC,  HWCAP2_MTE, "SYNC"  },
+	{ PR_MTE_TCF_ASYNC, HWCAP2_MTE, "ASYNC" },
+	{ PR_MTE_TCF_SYNC | PR_MTE_TCF_ASYNC,  HWCAP2_MTE, "SYNC+ASYNC"  },
+};
+
+int main(void)
+{
+	int i;
+
+	system_has_mte = getauxval(AT_HWCAP2) & HWCAP2_MTE;
+
+	ksft_print_header();
+	ksft_set_plan(5);
+
+	check_basic_read();
+	for (i = 0; i < ARRAY_SIZE(mte_modes); i++)
+		set_mode_test(mte_modes[i].name, mte_modes[i].hwcap2,
+			      mte_modes[i].mask);
+
+	ksft_print_cnts();
+
+	return 0;
+}
-- 
2.30.2

Re: [PATCH v1 4/4] kselftest/arm64: Add simple test for MTE prctl

[Joey Gouly]

Hi Mark,

On Thu, Mar 10, 2022 at 02:43:35PM +0000, Mark Brown wrote:
> The current tests use the prctls for various things but there's no
> coverage of the edges of the interface so add some basics. This isn't
> hugely useful as it is (it originally had some coverage for the
> combinations with asymmetric mode but we removed the prctl() for that)
> but it might be a helpful starting point for future work, for example
> covering error handling.
> 
> Signed-off-by: Mark Brown <broonie@kernel.org>
> ---

[..]

> diff --git a/tools/testing/selftests/arm64/mte/check_prctl.c b/tools/testing/selftests/arm64/mte/check_prctl.c
> new file mode 100644
> index 000000000000..500aefc5d7cd
> --- /dev/null
> +++ b/tools/testing/selftests/arm64/mte/check_prctl.c
> @@ -0,0 +1,123 @@
> +// SPDX-License-Identifier: GPL-2.0
> +// Copyright (C) 2022 ARM Limited
> +
> +#include <stdbool.h>
> +#include <stdio.h>
> +#include <string.h>
> +
> +#include <sys/auxv.h>
> +#include <sys/prctl.h>
> +
> +#include <asm/hwcap.h>
> +
> +#include "kselftest.h"
> +
> +static bool system_has_mte;

This looks unused (apart from being set in main()).

Thanks,
Joey

Re: [PATCH v1 4/4] kselftest/arm64: Add simple test for MTE prctl

[Mark Brown]

[-- Attachment #1: Type: text/plain, Size: 267 bytes --]

On Thu, Mar 10, 2022 at 03:33:06PM +0000, Joey Gouly wrote:
> On Thu, Mar 10, 2022 at 02:43:35PM +0000, Mark Brown wrote:

> > +static bool system_has_mte;

> This looks unused (apart from being set in main()).

It is, it was used in the asymmetric bits of the test.

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 488 bytes --]

Re: [PATCH v1 4/4] kselftest/arm64: Add simple test for MTE prctl

[Shuah Khan]

On 3/10/22 7:43 AM, Mark Brown wrote:
> The current tests use the prctls for various things but there's no
> coverage of the edges of the interface so add some basics. This isn't
> hugely useful as it is (it originally had some coverage for the
> combinations with asymmetric mode but we removed the prctl() for that)
> but it might be a helpful starting point for future work, for example
> covering error handling.
> 
> Signed-off-by: Mark Brown <broonie@kernel.org>
> ---
>   tools/testing/selftests/arm64/mte/.gitignore  |   1 +
>   .../testing/selftests/arm64/mte/check_prctl.c | 123 ++++++++++++++++++
>   2 files changed, 124 insertions(+)
>   create mode 100644 tools/testing/selftests/arm64/mte/check_prctl.c
> 

Looks good to me.

Reviewed-by: Shuah Khan <skhan@linuxfoundation.org>

thanks,
-- Shuah