Re: [RFC PATCH] bpf: s390: add JIT support for multi-function programs

[Ilya Leoshkevich <iii@linux.ibm.com>]

> Am 27.08.2019 um 16:25 schrieb Yauheni Kaliuta <yauheni.kaliuta@redhat.com>:
> 
> Hi, Ilya!
> 
>>>>>> On Tue, 27 Aug 2019 15:21:30 +0200, Ilya Leoshkevich  wrote:
> 
>>> Am 26.08.2019 um 20:20 schrieb Yauheni Kaliuta <yauheni.kaliuta@redhat.com>:
>>> 
>>> test_verifier (5.3-rc6):
>>> 
>>> without patch:
>>> Summary: 1501 PASSED, 0 SKIPPED, 47 FAILED
>>> 
>>> with patch:
>>> Summary: 1540 PASSED, 0 SKIPPED, 8 FAILED
> 
>> Are you per chance running with a testsuite patch like this one?
> 
>> --- a/tools/testing/selftests/bpf/test_verifier.c
>> +++ b/tools/testing/selftests/bpf/test_verifier.c
>> @@ -846,7 +846,7 @@ static int do_prog_test_run(int fd_prog, bool unpriv, uint32_t expected_val,
>> 				tmp, &size_tmp, &retval, NULL);
>> 	if (unpriv)
>> 		set_admin(false);
>> -	if (err && errno != 524/*ENOTSUPP*/ && errno != EPERM) {
>> +	if (err && errno != EPERM) {
>> 		printf("Unexpected bpf_prog_test_run error ");
>> 		return err;
>> 	}
> 
>> Without it, all the failures appear to be masked for me.
> 
> BTW, I have several failures because of low BPF_SIZE_MAX. If I
> increase it, some tests pass (#585/p ld_abs: vlan + abs, test 1),
> but some crash (#587/p ld_abs: jump around ld_abs, haven't
> found the reason yet).
> 
> Have you observed anything like that?

Yes, this is because right now JIT generates clrj and friends,
which can jump only by +-32k. Improving this is actually my next task
(after fixing more or less "obvious" test suite problems).