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 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.

Thanks,
drew