selftests/arm64: Log errors in verify_mte_pointer_validity()

When we detect a problem in verify_mte_pointer_validity() while checking
tags we don't log what the problem was which makes debugging harder. Add
some diagnostics.

Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Shuah Khan <skhan@linuxfoundation.org>
Link: https://lore.kernel.org/r/20220510164520.768783-2-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

Author: broonie

tools/testing/selftests/arm64/mte/check_tags_inclusion.c

@@ -25,19 +25,25 @@ static int verify_mte_pointer_validity(char *ptr, int mode)
 	/* Check the validity of the tagged pointer */
 	memset((void *)ptr, '1', BUFFER_SIZE);
 	mte_wait_after_trig();
-	if (cur_mte_cxt.fault_valid)
+	if (cur_mte_cxt.fault_valid) {
+		ksft_print_msg("Unexpected fault recorded for %p-%p in mode %x\n",
+			       ptr, ptr + BUFFER_SIZE, mode);
 		return KSFT_FAIL;
+	}
 	/* Proceed further for nonzero tags */
 	if (!MT_FETCH_TAG((uintptr_t)ptr))
 		return KSFT_PASS;
 	mte_initialize_current_context(mode, (uintptr_t)ptr, BUFFER_SIZE + 1);
 	/* Check the validity outside the range */
 	ptr[BUFFER_SIZE] = '2';
 	mte_wait_after_trig();
-	if (!cur_mte_cxt.fault_valid)
+	if (!cur_mte_cxt.fault_valid) {
+		ksft_print_msg("No valid fault recorded for %p in mode %x\n",
+			       ptr, mode);
 		return KSFT_FAIL;
-	else
+	} else {
 		return KSFT_PASS;
+	}
 }
 
 static int check_single_included_tags(int mem_type, int mode)