[kvm-unit-tests PATCH] s390x: Add specification exception test

Janis Schoetterl-Glausch
2021-07-06T12:03:46Z

Generate specification exceptions and check that they occur.
Also generate specification exceptions during a transaction,
which results in another interruption code.
With the iterations argument one can check if specification
exception interpretation occurs, e.g. by using a high value and
checking that the debugfs counters are substantially lower.
The argument is also useful for estimating the performance benefit
of interpretation.

Signed-off-by: Janis Schoetterl-Glausch <scgl@linux.ibm.com>
---
s390x/Makefile | 1 +
lib/s390x/asm/arch_def.h | 1 +
s390x/spec_ex.c | 344 +++++++++++++++++++++++++++++++++++++++
s390x/unittests.cfg | 3 +
4 files changed, 349 insertions(+)
create mode 100644 s390x/spec_ex.c

diff --git a/s390x/Makefile b/s390x/Makefile
index 8820e99..be100d3 100644
--- a/s390x/Makefile
+++ b/s390x/Makefile
@@ -23,6 +23,7 @@ tests += $(TEST_DIR)/sie.elf
tests += $(TEST_DIR)/mvpg.elf
tests += $(TEST_DIR)/uv-host.elf
tests += $(TEST_DIR)/edat.elf
+tests += $(TEST_DIR)/spec_ex.elf

tests_binary = $(patsubst %.elf,%.bin,$(tests))
ifneq ($(HOST_KEY_DOCUMENT),)
diff --git a/lib/s390x/asm/arch_def.h b/lib/s390x/asm/arch_def.h
index 15cf7d4..7cb0b92 100644
--- a/lib/s390x/asm/arch_def.h
+++ b/lib/s390x/asm/arch_def.h
@@ -229,6 +229,7 @@ static inline uint64_t stctg(int cr)
return value;
}

+#define CTL0_TRANSACT_EX_CTL (63 - 8)
#define CTL0_LOW_ADDR_PROT (63 - 35)
#define CTL0_EDAT (63 - 40)
#define CTL0_IEP (63 - 43)
diff --git a/s390x/spec_ex.c b/s390x/spec_ex.c
new file mode 100644
index 0000000..2e05bfb
--- /dev/null
+++ b/s390x/spec_ex.c
@@ -0,0 +1,344 @@
+#include <stdlib.h>
+#include <htmintrin.h>
+#include <libcflat.h>
+#include <asm/barrier.h>
+#include <asm/interrupt.h>
+#include <asm/facility.h>
+
+struct lowcore *lc = (struct lowcore *) 0;
+
+static bool expect_early;
+static struct psw expected_early_pgm_psw;
+static struct psw fixup_early_pgm_psw;
+
+static void fixup_early_pgm_ex(void)
+{
+ if (expect_early) {
+ report(expected_early_pgm_psw.mask == lc->pgm_old_psw.mask
+ && expected_early_pgm_psw.addr == lc->pgm_old_psw.addr,
+ "Early program new PSW as expected");
+ expect_early = false;
+ }
+ lc->pgm_old_psw = fixup_early_pgm_psw;
+}
+
+static void lpsw(uint64_t psw)
+{
+ uint32_t *high, *low;
+ uint64_t r0 = 0, r1 = 0;
+
+ high = (uint32_t *) &fixup_early_pgm_psw.mask;
+ low = high + 1;
+
+ asm volatile (
+ " epsw %0,%1\n"
+ " st %0,%[high]\n"
+ " st %1,%[low]\n"
+ " larl %0,nop%=\n"
+ " stg %0,%[addr]\n"
+ " lpsw %[psw]\n"
+ "nop%=: nop\n"
+ : "+&r"(r0), "+&a"(r1), [high] "=&R"(*high), [low] "=&R"(*low)
+ , [addr] "=&R"(fixup_early_pgm_psw.addr)
+ : [psw] "Q"(psw)
+ : "cc", "memory"
+ );
+}
+
+static void psw_bit_31_32_are_1_0(void)
+{
+ uint64_t bad_psw = 0x000800015eadbeef;
+
+ //bit 12 gets inverted when extending to 128-bit PSW
+ expected_early_pgm_psw.mask = 0x0000000100000000;
+ expected_early_pgm_psw.addr = 0x000000005eadbeef;
+ expect_early = true;
+ lpsw(bad_psw);
+}
+
+static void bad_alignment(void)
+{
+ uint32_t words[5] = {0, 0, 0};
+ uint32_t (*bad_aligned)[4];
+
+ register uint64_t r1 asm("6");
+ register uint64_t r2 asm("7");
+ if (((uintptr_t)&words[0]) & 0xf) {
+ bad_aligned = (uint32_t (*)[4])&words[0];
+ } else {
+ bad_aligned = (uint32_t (*)[4])&words[1];
+ }
+ asm volatile ("lpq %0,%2"
+ : "=r"(r1), "=r"(r2)
+ : "T"(*bad_aligned)
+ );
+}
+
+static void not_even(void)
+{
+ uint64_t quad[2];
+
+ register uint64_t r1 asm("7");
+ register uint64_t r2 asm("8");
+ asm volatile (".insn rxy,0xe3000000008f,%0,%2" //lpq %0,%2
+ : "=r"(r1), "=r"(r2)
+ : "T"(quad)
+ );
+}
+
+struct spec_ex_trigger {
+ const char *name;
+ void (*func)(void);
+ bool transactable;
+ void (*fixup)(void);
+};
+
+static const struct spec_ex_trigger spec_ex_triggers[] = {
+ { "psw_bit_31_32_are_1_0", &psw_bit_31_32_are_1_0, false, &fixup_early_pgm_ex},
+ { "bad_alignment", &bad_alignment, true, NULL},
+ { "not_even", &not_even, true, NULL},
+ { NULL, NULL, true, NULL},
+};
+
+struct args {
+ uint64_t iterations;
+ uint64_t max_retries;
+ uint64_t suppress_info;
+ uint64_t max_failures;
+ bool diagnose;
+};
+
+static void test_spec_ex(struct args *args,
+ const struct spec_ex_trigger *trigger)
+{
+ uint16_t expected_pgm = PGM_INT_CODE_SPECIFICATION;
+ uint16_t pgm;
+ unsigned int i;
+
+ register_pgm_cleanup_func(trigger->fixup);
+ for (i = 0; i < args->iterations; i++) {
+ expect_pgm_int();
+ trigger->func();
+ pgm = clear_pgm_int();
+ if (pgm != expected_pgm) {
+ report(0,
+ "Program interrupt: expected(%d) == received(%d)",
+ expected_pgm,
+ pgm);
+ return;
+ }
+ }
+ report(1,
+ "Program interrupt: always expected(%d) == received(%d)",
+ expected_pgm,
+ expected_pgm);
+}
+
+#define TRANSACTION_COMPLETED 4
+#define TRANSACTION_MAX_RETRIES 5
+
+static int __attribute__((nonnull))
+with_transaction(void (*trigger)(void), struct __htm_tdb *diagnose)
+{
+ int cc;
+
+ cc = __builtin_tbegin(diagnose);
+ if (cc == _HTM_TBEGIN_STARTED) {
+ 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 = lc->pgm_int_code;
+ if (pgm == 0) {
+ continue;
+ } else if (pgm == expected_pgm) {
+ return 0;
+ }
+ }
+ return trans_result;
+ }
+ return -TRANSACTION_MAX_RETRIES;
+}
+
+#define report_info_if(cond, fmt, ...) \
+ do { \
+ if (cond) { \
+ report_info(fmt, ##__VA_ARGS__);\
+ } \
+ } while (0)
+
+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, failures = 0;
+ 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);
+ for (i = 0; i < args->iterations && failures <= args->max_failures; i++) {
+ trans_result = retry_transaction(trigger, args->max_retries, &diag.tdb, expected_pgm);
+ switch (trans_result) {
+ case 0:
+ continue;
+ case -_HTM_TBEGIN_INDETERMINATE:
+ case -_HTM_TBEGIN_PERSISTENT:
+ report_info_if(failures < args->suppress_info,
+ "transaction failed with cc %d",
+ -trans_result);
+ break;
+ case -_HTM_TBEGIN_TRANSIENT:
+ report(0,
+ "Program interrupt: expected(%d) == received(%d)",
+ expected_pgm,
+ clear_pgm_int());
+ goto out;
+ case -TRANSACTION_COMPLETED:
+ report(0,
+ "Transaction completed without exception");
+ goto out;
+ case -TRANSACTION_MAX_RETRIES:
+ report_info_if(failures < args->suppress_info,
+ "Retried transaction %u times without exception",
+ 10);
+ break;
+ default:
+ report(0, "Invalid return transaction result");
+ goto out;
+ }
+
+ report_info_if(failures < args->suppress_info,
+ "transaction abort code: %llu", diag.tdb.abort_code);
+ if (args->diagnose && failures < args->suppress_info) {
+ for (i = 0; i < 32; i++) {
+ report_info("diag+%03d: %016lx", i*8, diag.dwords[i]);
+ }
+ }
+ ++failures;
+ }
+ if (failures <= args->max_failures) {
+ report(1,
+ "Program interrupt: always expected(%d) == received(%d), transaction failures: %u",
+ expected_pgm,
+ expected_pgm,
+ failures);
+ } else {
+ report(0,
+ "Too many transaction failures: %u", failures);
+ }
+ report_info_if(failures > args->suppress_info,
+ "Suppressed some transaction failure information messages");
+
+out:
+ ctl_clear_bit(0, CTL0_TRANSACT_EX_CTL);
+}
+
+static struct args parse_args(int argc, char **argv)
+{
+ struct args args = {
+ .iterations = 1,
+ .max_retries = 20,
+ .suppress_info = 20,
+ .diagnose = false
+ };
+ unsigned int i;
+ long parsed;
+ bool error, max_failures = false;
+ char *end;
+
+ for (i = 1; i < argc; i++) {
+ error = true;
+ if (i < argc - 1) {
+ error = *argv[i+1] == '\0';
+ parsed = strtol(argv[i+1], &end, 10);
+ error |= *end != '\0';
+ error |= parsed < 0;
+ }
+
+ if (!strcmp("--iterations", argv[i])) {
+ if (error)
+ report_abort("--iterations needs a positive parameter");
+ args.iterations = parsed;
+ ++i;
+ } else if (!strcmp("--max-retries", argv[i])) {
+ if (error)
+ report_abort("--max-retries needs a positive parameter");
+ args.max_retries = parsed;
+ ++i;
+ } else if (!strcmp("--suppress-info", argv[i])) {
+ if (error)
+ report_abort("--suppress-info needs a positive parameter");
+ args.suppress_info = parsed;
+ ++i;
+ } else if (!strcmp("--max-failures", argv[i])) {
+ if (error)
+ report_abort("--max-failures needs a positive parameter");
+ args.max_failures = parsed;
+ max_failures = true;
+ ++i;
+ } else if (!strcmp("--diagnose", argv[i])) {
+ args.diagnose = true;
+ } else if (!strcmp("--no-diagnose", argv[i])) {
+ args.diagnose = false;
+ } else {
+ report_abort("Unsupported parameter '%s'",
+ argv[i]);
+ }
+ }
+
+ if (!max_failures)
+ args.max_failures = args.iterations / 1000;
+
+ 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);
+ test_spec_ex(&args, &spec_ex_triggers[i]);
+ report_prefix_pop();
+ }
+ 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();
+}
diff --git a/s390x/unittests.cfg b/s390x/unittests.cfg
index a0ec886..b93aead 100644
--- a/s390x/unittests.cfg
+++ b/s390x/unittests.cfg
@@ -106,3 +106,6 @@ timeout = 10

[edat]
file = edat.elf
+
+[spec_ex]
+file = spec_ex.elf

base-commit: bc6f264386b4cb2cadc8b2492315f3e6e8a801a2
--
2.31.1