On 10/5/21 4:51 PM, Thomas Huth wrote:
> On 05/10/2021 11.09, Janis Schoetterl-Glausch wrote:
>> Generate specification exceptions and check that they occur.
>> 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@xxxxxxxxxxxxx>
>> ---
>> s390x/Makefile | 1 +
>> s390x/spec_ex.c | 182 ++++++++++++++++++++++++++++++++++++++++++++
>> s390x/unittests.cfg | 3 +
>> 3 files changed, 186 insertions(+)
>> create mode 100644 s390x/spec_ex.c
>>
>> diff --git a/s390x/Makefile b/s390x/Makefile
>> index ef8041a..57d7c9e 100644
>> --- a/s390x/Makefile
>> +++ b/s390x/Makefile
>> @@ -24,6 +24,7 @@ tests += $(TEST_DIR)/mvpg.elf
>> tests += $(TEST_DIR)/uv-host.elf
>> tests += $(TEST_DIR)/edat.elf
>> tests += $(TEST_DIR)/mvpg-sie.elf
>> +tests += $(TEST_DIR)/spec_ex.elf
>> tests_binary = $(patsubst %.elf,%.bin,$(tests))
>> ifneq ($(HOST_KEY_DOCUMENT),)
>> diff --git a/s390x/spec_ex.c b/s390x/spec_ex.c
>> new file mode 100644
>> index 0000000..dd0ee53
>> --- /dev/null
>> +++ b/s390x/spec_ex.c
>> @@ -0,0 +1,182 @@
>> +// SPDX-License-Identifier: GPL-2.0-only
>> +/*
>> + * © Copyright IBM Corp. 2021
>
> Could we please avoid non-ASCII characters in source code if possible? ... it's maybe best if you do the Copyright line similar to the other *.c files from IBM that are already in the repository.
Yes, I'll remove it. I thought it would be fine since it's in a comment,
didn't consider that it might cause trouble with some mail clients.
So that's grounds for removal by itself.
>
>> + * Specification exception test.
>> + * Tests that specification exceptions occur when expected.
>> + */
>> +#include <stdlib.h>
>> +#include <libcflat.h>
>> +#include <asm/interrupt.h>
>> +#include <asm/facility.h>
>> +
>> +static struct lowcore *lc = (struct lowcore *) 0;
>> +
>> +static bool expect_invalid_psw;
>> +static struct psw expected_psw;
>> +static struct psw fixup_psw;
>> +
>> +/* The standard program exception handler cannot deal with invalid old PSWs,
>> + * especially not invalid instruction addresses, as in that case one cannot
>> + * find the instruction following the faulting one from the old PSW.
>> + * The PSW to return to is set by load_psw.
>> + */
>> +static void fixup_invalid_psw(void)
>> +{
>> + if (expect_invalid_psw) {
>> + report(expected_psw.mask == lc->pgm_old_psw.mask
>> + && expected_psw.addr == lc->pgm_old_psw.addr,
>> + "Invalid program new PSW as expected");
>> + expect_invalid_psw = false;
>> + }
>> + lc->pgm_old_psw = fixup_psw;
>> +}
>> +
>> +static void load_psw(struct psw psw)
>> +{
>> + uint64_t r0 = 0, r1 = 0;
>> +
>> + asm volatile (
>> + " epsw %0,%1\n"
>> + " st %0,%[mask]\n"
>> + " st %1,4+%[mask]\n"
>> + " larl %0,nop%=\n"
>> + " stg %0,%[addr]\n"
>> + " lpswe %[psw]\n"
>> + "nop%=: nop\n"
>> + : "+&r"(r0), "+&a"(r1), [mask] "=&R"(fixup_psw.mask),
>> + [addr] "=&R"(fixup_psw.addr)
>
> stg uses long displacement, so maybe the constraint should rather be "T" instead?
Good catch.
>
>> + : [psw] "Q"(psw)
>> + : "cc", "memory"
>> + );
>> +}
>> +
[...]
>> +static struct args parse_args(int argc, char **argv)
>> +{
>> + struct args args = {
>> + .iterations = 1,
>> + };
>> + unsigned int i;
>> + long arg;
>> + bool no_arg;
>> + char *end;
>> +
>> + for (i = 1; i < argc; i++) {
>> + no_arg = true;
>> + if (i < argc - 1) {
>> + no_arg = *argv[i+1] == '\0';
>> + arg = strtol(argv[i+1], &end, 10);
>
> Nit: It's more common to use spaces around the "+" (i.e. "i + 1")
Ok
>
>> + no_arg |= *end != '\0';
>> + no_arg |= arg < 0;
>> + }
>> +
>> + if (!strcmp("--iterations", argv[i])) {
>> + if (no_arg)
>> + report_abort("--iterations needs a positive parameter");
>> + args.iterations = arg;
>> + ++i;
>> + } else {
>> + 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);
>> + test_spec_ex(&args, &spec_ex_triggers[i]);
>> + report_prefix_pop();
>> + }
>> + report_prefix_pop();
>> +
>> + return report_summary();
>> +}
>
> Apart from the nits, this looks fine to me.
Thanks for the review.
>
> Thomas
>
