[kvm-unit-tests PATCH v5 2/2] s390x: Test specification exceptions during transaction

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Program interruptions during transactional execution cause other
interruption codes.
Check that we see the expected code for (some) specification exceptions.

Signed-off-by: Janis Schoetterl-Glausch <scgl@xxxxxxxxxxxxx>
---
 lib/s390x/asm/arch_def.h |   1 +
 s390x/spec_ex.c          | 199 ++++++++++++++++++++++++++++++++++++++-
 2 files changed, 195 insertions(+), 5 deletions(-)

diff --git a/lib/s390x/asm/arch_def.h b/lib/s390x/asm/arch_def.h
index 8fbc451c..94b104ca 100644
--- a/lib/s390x/asm/arch_def.h
+++ b/lib/s390x/asm/arch_def.h
@@ -60,6 +60,7 @@ struct short_psw {
 #define PSW_MASK_BA			0x0000000080000000UL
 #define PSW_MASK_64			(PSW_MASK_BA | PSW_MASK_EA)
 
+#define CTL0_TRANSACT_EX_CTL			(63 -  8)
 #define CTL0_LOW_ADDR_PROT			(63 - 35)
 #define CTL0_EDAT				(63 - 40)
 #define CTL0_FETCH_PROTECTION_OVERRIDE		(63 - 38)
diff --git a/s390x/spec_ex.c b/s390x/spec_ex.c
index 77fc6246..1f1d7209 100644
--- a/s390x/spec_ex.c
+++ b/s390x/spec_ex.c
@@ -4,12 +4,18 @@
  *
  * Specification exception test.
  * Tests that specification exceptions occur when expected.
+ * This includes specification exceptions occurring during transactional execution
+ * as these result in another interruption code (the transactional-execution-aborted
+ * bit is set).
  *
  * Can be extended by adding triggers to spec_ex_triggers, see comments below.
  */
 #include <stdlib.h>
+#include <htmintrin.h>
 #include <libcflat.h>
+#include <asm/barrier.h>
 #include <asm/interrupt.h>
+#include <asm/facility.h>
 
 static bool invalid_psw_expected;
 static struct psw expected_psw;
@@ -134,20 +140,22 @@ static int not_even(void)
 /*
  * Harness for specification exception testing.
  * func only triggers exception, reporting is taken care of automatically.
+ * If a trigger is transactable it will also  be executed during a transaction.
  */
 struct spec_ex_trigger {
 	const char *name;
 	int (*func)(void);
+	bool transactable;
 	void (*fixup)(void);
 };
 
 /* List of all tests to execute */
 static const struct spec_ex_trigger spec_ex_triggers[] = {
-	{ "psw_bit_12_is_1", &psw_bit_12_is_1, &fixup_invalid_psw },
-	{ "short_psw_bit_12_is_0", &short_psw_bit_12_is_0, &fixup_invalid_psw },
-	{ "bad_alignment", &bad_alignment, NULL },
-	{ "not_even", &not_even, NULL },
-	{ NULL, NULL, NULL },
+	{ "psw_bit_12_is_1", &psw_bit_12_is_1, false, &fixup_invalid_psw },
+	{ "short_psw_bit_12_is_0", &short_psw_bit_12_is_0, false, &fixup_invalid_psw },
+	{ "bad_alignment", &bad_alignment, true, NULL },
+	{ "not_even", &not_even, true, NULL },
+	{ NULL, NULL, false, NULL },
 };
 
 static void test_spec_ex(const struct spec_ex_trigger *trigger)
@@ -164,10 +172,181 @@ static void test_spec_ex(const struct spec_ex_trigger *trigger)
 	check_pgm_int_code(PGM_INT_CODE_SPECIFICATION);
 }
 
+#define TRANSACTION_COMPLETED 4
+#define TRANSACTION_MAX_RETRIES 5
+
+/*
+ * NULL must be passed to __builtin_tbegin via constant, forbid diagnose from
+ * being NULL to keep things simple
+ */
+static int __attribute__((nonnull))
+with_transaction(int (*trigger)(void), struct __htm_tdb *diagnose)
+{
+	int cc;
+
+	cc = __builtin_tbegin(diagnose);
+	/*
+	 * Everything between tbegin and tend is part of the transaction,
+	 * which either completes in its entirety or does not have any effect.
+	 * If the transaction fails, execution is reset to this point with another
+	 * condition code indicating why the transaction failed.
+	 */
+	if (cc == _HTM_TBEGIN_STARTED) {
+		/*
+		 * return code is meaningless: transaction needs to complete
+		 * in order to return and completion indicates a test failure
+		 */
+		trigger();
+		__builtin_tend();
+		return TRANSACTION_COMPLETED;
+	} else {
+		return cc;
+	}
+}
+
+static int retry_transaction(const struct spec_ex_trigger *trigger, unsigned int max_retries,
+			     struct __htm_tdb *tdb, uint16_t expected_pgm)
+{
+	int trans_result, i;
+	uint16_t pgm;
+
+	for (i = 0; i < max_retries; i++) {
+		expect_pgm_int();
+		trans_result = with_transaction(trigger->func, tdb);
+		if (trans_result == _HTM_TBEGIN_TRANSIENT) {
+			mb();
+			pgm = lowcore.pgm_int_code;
+			if (pgm == expected_pgm)
+				return 0;
+			else if (pgm == 0)
+				/*
+				 * Transaction failed for unknown reason but not because
+				 * of an unexpected program exception. Give it another
+				 * go so that hopefully it reaches the triggering instruction.
+				 */
+				continue;
+		}
+		return trans_result;
+	}
+	return TRANSACTION_MAX_RETRIES;
+}
+
+struct args {
+	uint64_t max_retries;
+	bool diagnose;
+};
+
+static void test_spec_ex_trans(struct args *args, const struct spec_ex_trigger *trigger)
+{
+	const uint16_t expected_pgm = PGM_INT_CODE_SPECIFICATION
+				      | PGM_INT_CODE_TX_ABORTED_EVENT;
+	union {
+		struct __htm_tdb tdb;
+		uint64_t dwords[sizeof(struct __htm_tdb) / sizeof(uint64_t)];
+	} diag;
+	unsigned int i;
+	int trans_result;
+
+	if (!test_facility(73)) {
+		report_skip("transactional-execution facility not installed");
+		return;
+	}
+	ctl_set_bit(0, CTL0_TRANSACT_EX_CTL); /* enable transactional-exec */
+
+	register_pgm_cleanup_func(trigger->fixup);
+	trans_result = retry_transaction(trigger, args->max_retries, &diag.tdb, expected_pgm);
+	register_pgm_cleanup_func(NULL);
+	switch (trans_result) {
+	case 0:
+		report_pass("Program interrupt: expected(%d) == received(%d)",
+			    expected_pgm, expected_pgm);
+		break;
+	case _HTM_TBEGIN_INDETERMINATE:
+	case _HTM_TBEGIN_PERSISTENT:
+		report_info("transaction failed with cc %d", trans_result);
+		report_info("transaction abort code: %llu", diag.tdb.abort_code);
+		if (args->diagnose)
+			for (i = 0; i < 32; i++)
+				report_info("diag+%03d: %016lx", i * 8, diag.dwords[i]);
+		break;
+	case _HTM_TBEGIN_TRANSIENT:
+		report_fail("Program interrupt: expected(%d) == received(%d)",
+			    expected_pgm, clear_pgm_int());
+		break;
+	case TRANSACTION_COMPLETED:
+		report_fail("Transaction completed without exception");
+		break;
+	case TRANSACTION_MAX_RETRIES:
+		report_skip("Transaction retried %lu times with transient failures, giving up",
+			    args->max_retries);
+		break;
+	default:
+		report_fail("Invalid transaction result");
+		break;
+	}
+
+	ctl_clear_bit(0, CTL0_TRANSACT_EX_CTL);
+}
+
+static bool parse_unsigned(const char *arg, unsigned int *out)
+{
+	char *end;
+	long num;
+
+	if (arg[0] == '\0')
+		return false;
+	num = strtol(arg, &end, 10);
+	if (end[0] != '\0' || num < 0)
+		return false;
+	*out = num;
+	return true;
+}
+
+static struct args parse_args(int argc, char **argv)
+{
+	struct args args = {
+		.max_retries = 20,
+		.diagnose = false
+	};
+	unsigned int i, arg;
+	bool has_arg;
+	const char *flag;
+
+	for (i = 1; i < argc; i++) {
+		if (i + 1 < argc)
+			has_arg = parse_unsigned(argv[i + 1], &arg);
+		else
+			has_arg = false;
+
+		flag = "--max-retries";
+		if (!strcmp(flag, argv[i])) {
+			if (!has_arg)
+				report_abort("%s needs a positive parameter", flag);
+			args.max_retries = arg;
+			++i;
+			continue;
+		}
+		if (!strcmp("--diagnose", argv[i])) {
+			args.diagnose = true;
+			continue;
+		}
+		if (!strcmp("--no-diagnose", argv[i])) {
+			args.diagnose = false;
+			continue;
+		}
+		report_abort("Unsupported parameter '%s'",
+			     argv[i]);
+	}
+
+	return args;
+}
+
 int main(int argc, char **argv)
 {
 	unsigned int i;
 
+	struct args args = parse_args(argc, argv);
+
 	report_prefix_push("specification exception");
 	for (i = 0; spec_ex_triggers[i].name; i++) {
 		report_prefix_push(spec_ex_triggers[i].name);
@@ -176,5 +355,15 @@ int main(int argc, char **argv)
 	}
 	report_prefix_pop();
 
+	report_prefix_push("specification exception during transaction");
+	for (i = 0; spec_ex_triggers[i].name; i++) {
+		if (spec_ex_triggers[i].transactable) {
+			report_prefix_push(spec_ex_triggers[i].name);
+			test_spec_ex_trans(&args, &spec_ex_triggers[i]);
+			report_prefix_pop();
+		}
+	}
+	report_prefix_pop();
+
 	return report_summary();
 }
-- 
2.36.1




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