RE: [PATCH v1 4/4] selftests: arm64: Verify that all possible vector lengths are handled

As part of the enumeration interface for setting vector lengths it is valid to set vector lengths not supported in the system, these will be rounded to a supported vector length and returned from the prctl(). Add a test which exercises this for every valid vector length and makes sure that the return value is as expected and that this is reflected in the actual system state.

Signed-off-by: Mark Brown broonie@kernel.org

tools/testing/selftests/arm64/fp/vec-syscfg.c | 76 +++++++++++++++++++ 1 file changed, 76 insertions(+)

diff --git a/tools/testing/selftests/arm64/fp/vec-syscfg.c b/tools/testing/selftests/arm64/fp/vec-syscfg.c index 9d6ac843e651..61e9704e03fe 100644 --- a/tools/testing/selftests/arm64/fp/vec-syscfg.c +++ b/tools/testing/selftests/arm64/fp/vec-syscfg.c @@ -540,6 +540,81 @@ static void prctl_set_onexec(struct vec_data *data) file_write_integer(data->default_vl_file, data->default_vl); }

+/* For each VQ verify that setting via prctl() does the right thing */ +static void prctl_set_all_vqs(struct vec_data *data) +{

• int ret, vq, vl, new_vl;
• int errors = 0;
• for (vq = SVE_VQ_MIN; vq <= SVE_VQ_MAX; vq++) {

• vl = sve_vl_from_vq(vq);
  

• /* Attempt to set the VL */
  

• ret = prctl(data->prctl_set, vl);
  

• if (ret < 0) {
  

• 	errors++;
  

• 	ksft_print_msg("%s prctl set failed for %d: %d
  

(%s)\n",

• 		       data->name, vl,
  

• 		       errno, strerror(errno));
  

• 	continue;
  

• }
  

• new_vl = ret & PR_SVE_VL_LEN_MASK;
  

• /* Check that we actually have the reported new VL */
  

• if (data->rdvl() != new_vl) {
  

• 	ksft_print_msg("Set %s VL %d but RDVL
  

reports %d\n",

• 		       data->name, new_vl, data->rdvl());
  

• 	errors++;
  

• }
  

• /* Was that the VL we asked for? */
  

• if (new_vl == vl)
  

• 	continue;
  

• /* Should round up to the minimum VL if below it */
  

• if (vl < data->min_vl) {
  

• 	if (new_vl != data->min_vl) {
  

• 		ksft_print_msg("%s VL %d returned %d not
  

minimum %d\n",

• 			       data->name, vl, new_vl,
  

• 			       data->min_vl);
  

• 		errors++;
  

• 	}
  

• 	continue;
  

• }
  

• /* Should round down to maximum VL if above it */
  

• if (vl > data->max_vl) {
  

• 	if (new_vl != data->max_vl) {
  

• 		ksft_print_msg("%s VL %d returned %d not
  

maximum %d\n",

• 			       data->name, vl, new_vl,
  

• 			       data->max_vl);
  

• 		errors++;
  

• 	}
  

• 	continue;
  

• }
  

Hello,

Since (new_vl < vl) is expected here:

• /* Otherwise we should've rounded down */
  

• if (!(new_vl < vl)) {
  

• 	ksft_print_msg("%s VL %d returned %d, did not round
  

down\n",

• 		       data->name, vl, new_vl);
  

• 	errors++;
  

• 	continue;
  

• }
  

I think following two lines should be removed:

• /* We should've hit one of the other cases... */
  

• ksft_print_msg("%s VL %d returned %d test logic failure\n",
  

• 	       data->name, vl, new_vl);
  

• errors++;
  

Actually I tried to run these sve tests update on A64FX and got the above error:

# # SVE VL 48 returned 32 test logic failure

but returning 32 is expected behavior as A64FX's supported VL lens are 16, 32, 64.

Thanks, Misono

• }
• ksft_test_result(errors == 0, "%s prctl() set all VLs, %d errors\n",

• 	 data->name, errors);
  

+}

typedef void (*test_type)(struct vec_data *);

static const test_type tests[] = { @@ -557,6 +632,7 @@ static const test_type tests[] = { prctl_set_no_child, prctl_set_for_child, prctl_set_onexec,

• prctl_set_all_vqs,

};

int main(void)

2.20.1

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