Re: [External] Re: [PATCH v3 3/3] RISC-V: selftests: Add TEST_ZICBOM into CBO tests

[Andrew Jones <ajones@ventanamicro.com>]

On Mon, Jan 13, 2025 at 07:49:39PM +0800, yunhui cui wrote:
> Hi drew,
> 
> On Mon, Jan 13, 2025 at 5:18 PM Andrew Jones <ajones@ventanamicro.com> wrote:
> >
> > On Mon, Jan 13, 2025 at 04:36:35PM +0800, Yunhui Cui wrote:
> > > Add test for Zicbom and its block size into CBO tests, when
> > > Zicbom is present, test that cbo.clean/flush may be issued and works.
> > > As the software can't verify the clean/flush functions, we just judged
> > > that cbo.clean/flush isn't executed illegally.
> > >
> > > Signed-off-by: Yunhui Cui <cuiyunhui@bytedance.com>
> > > ---
> > >  tools/testing/selftests/riscv/hwprobe/cbo.c | 49 ++++++++++++++++++---
> > >  1 file changed, 43 insertions(+), 6 deletions(-)
> > >
> > > diff --git a/tools/testing/selftests/riscv/hwprobe/cbo.c b/tools/testing/selftests/riscv/hwprobe/cbo.c
> > > index a40541bb7c7d..b63e23f95e08 100644
> > > --- a/tools/testing/selftests/riscv/hwprobe/cbo.c
> > > +++ b/tools/testing/selftests/riscv/hwprobe/cbo.c
> > > @@ -81,6 +81,30 @@ static bool is_power_of_2(__u64 n)
> > >       return n != 0 && (n & (n - 1)) == 0;
> > >  }
> > >
> > > +static void test_zicbom(void *arg)
> > > +{
> > > +     struct riscv_hwprobe pair = {
> > > +             .key = RISCV_HWPROBE_KEY_ZICBOM_BLOCK_SIZE,
> > > +     };
> > > +     cpu_set_t *cpus = (cpu_set_t *)arg;
> > > +     __u64 block_size;
> > > +     long rc;
> > > +
> > > +     rc = riscv_hwprobe(&pair, 1, sizeof(cpu_set_t), (unsigned long *)cpus, 0);
> > > +     block_size = pair.value;
> > > +     ksft_test_result(rc == 0 && pair.key == RISCV_HWPROBE_KEY_ZICBOM_BLOCK_SIZE &&
> > > +                      is_power_of_2(block_size), "Zicbom block size\n");
> > > +     ksft_print_msg("Zicbom block size: %llu\n", block_size);
> > > +
> > > +     illegal_insn = false;
> > > +     cbo_clean(&mem[block_size]);
> > > +     ksft_test_result(!illegal_insn, "cbo.clean\n");
> > > +
> > > +     illegal_insn = false;
> > > +     cbo_flush(&mem[block_size]);
> > > +     ksft_test_result(!illegal_insn, "cbo.flush\n");
> > > +}
> > > +
> > >  static void test_zicboz(void *arg)
> > >  {
> > >       struct riscv_hwprobe pair = {
> > > @@ -129,7 +153,7 @@ static void test_zicboz(void *arg)
> > >       ksft_test_result_pass("cbo.zero check\n");
> > >  }
> > >
> > > -static void check_no_zicboz_cpus(cpu_set_t *cpus)
> > > +static void check_no_zicbo_cpus(cpu_set_t *cpus, __u64 cbo)
> > >  {
> > >       struct riscv_hwprobe pair = {
> > >               .key = RISCV_HWPROBE_KEY_IMA_EXT_0,
> > > @@ -137,6 +161,7 @@ static void check_no_zicboz_cpus(cpu_set_t *cpus)
> > >       cpu_set_t one_cpu;
> > >       int i = 0, c = 0;
> > >       long rc;
> > > +     char *cbostr;
> > >
> > >       while (i++ < CPU_COUNT(cpus)) {
> > >               while (!CPU_ISSET(c, cpus))
> > > @@ -148,10 +173,13 @@ static void check_no_zicboz_cpus(cpu_set_t *cpus)
> > >               rc = riscv_hwprobe(&pair, 1, sizeof(cpu_set_t), (unsigned long *)&one_cpu, 0);
> > >               assert(rc == 0 && pair.key == RISCV_HWPROBE_KEY_IMA_EXT_0);
> > >
> > > -             if (pair.value & RISCV_HWPROBE_EXT_ZICBOZ)
> > > -                     ksft_exit_fail_msg("Zicboz is only present on a subset of harts.\n"
> > > -                                        "Use taskset to select a set of harts where Zicboz\n"
> > > -                                        "presence (present or not) is consistent for each hart\n");
> > > +             cbostr = cbo == RISCV_HWPROBE_EXT_ZICBOZ ? "Zicboz" : "Zicbom";
> > > +
> > > +             if (pair.value & cbo)
> > > +                     ksft_exit_fail_msg("%s is only present on a subset of harts.\n"
> > > +                                        "Use taskset to select a set of harts where %s\n"
> > > +                                        "presence (present or not) is consistent for each hart\n",
> > > +                                        cbostr, cbostr);
> > >               ++c;
> > >       }
> > >  }
> > > @@ -159,6 +187,7 @@ static void check_no_zicboz_cpus(cpu_set_t *cpus)
> > >  enum {
> > >       TEST_ZICBOZ,
> > >       TEST_NO_ZICBOZ,
> > > +     TEST_ZICBOM,
> > >       TEST_NO_ZICBOM,
> > >  };
> > >
> > > @@ -169,6 +198,7 @@ static struct test_info {
> > >  } tests[] = {
> > >       [TEST_ZICBOZ]           = { .nr_tests = 3, test_zicboz },
> > >       [TEST_NO_ZICBOZ]        = { .nr_tests = 1, test_no_zicboz },
> > > +     [TEST_ZICBOM]           = { .nr_tests = 3, test_zicbom },
> > >       [TEST_NO_ZICBOM]        = { .nr_tests = 3, test_no_zicbom },
> > >  };
> > >
> > > @@ -206,7 +236,14 @@ int main(int argc, char **argv)
> > >               tests[TEST_ZICBOZ].enabled = true;
> > >               tests[TEST_NO_ZICBOZ].enabled = false;
> > >       } else {
> > > -             check_no_zicboz_cpus(&cpus);
> > > +             check_no_zicbo_cpus(&cpus, RISCV_HWPROBE_EXT_ZICBOZ);
> > > +     }
> > > +
> > > +     if (pair.value & RISCV_HWPROBE_EXT_ZICBOM) {
> > > +             tests[TEST_ZICBOM].enabled = true;
> > > +             tests[TEST_NO_ZICBOM].enabled = false;
> > > +     } else {
> > > +             check_no_zicbo_cpus(&cpus, RISCV_HWPROBE_EXT_ZICBOM);
> > >       }
> > >
> > >       for (i = 0; i < ARRAY_SIZE(tests); ++i)
> > > --
> > > 2.39.2
> > >
> >
> > The test_no_zicbom() test needs to have the illegal instruction SIGILL
> > test for cbo.inval moved out into its own test. So, even when we have
> > zicbom we still test that cbo.inval generates a SIGILL.
> 
> Do you mean moving cbo_inval() into test_zicbom()? Then does
> cbo_inval(&mem[0]) also need to be tested in test_no_zicbom()?

No, I'd create a new test named test_no_cbo_inval(), which should always
run regardless of zicbom/zicboz detection.

Thanks,
drew