Re: [PATCH v5 12/13] selftests: riscv: Fix vector tests

[Andrew Jones]

On Fri, Jul 19, 2024 at 09:19:07AM GMT, Charlie Jenkins wrote:
> Overhaul the riscv vector tests to use kselftest_harness to help the
> test cases correctly report the results and decouple the individual test
> cases from each other. With this refactoring, only run the test cases is
> vector is reported and properly report the test case as skipped
> otherwise. The v_initval_nolibc test was previously not checking if
> vector was supported and used a function (malloc) which invalidates
> the state of the vector registers.
> 
> Signed-off-by: Charlie Jenkins <charlie@xxxxxxxxxxxx>
> ---
>  tools/testing/selftests/riscv/abi/ptrace           | Bin 0 -> 759368 bytes
>  tools/testing/selftests/riscv/vector/.gitignore    |   3 +-
>  tools/testing/selftests/riscv/vector/Makefile      |  17 +-
>  .../selftests/riscv/vector/v_exec_initval_nolibc.c |  84 +++++++
>  tools/testing/selftests/riscv/vector/v_helpers.c   |  56 +++++
>  tools/testing/selftests/riscv/vector/v_helpers.h   |   5 +
>  tools/testing/selftests/riscv/vector/v_initval.c   |  16 ++
>  .../selftests/riscv/vector/v_initval_nolibc.c      |  68 ------
>  .../testing/selftests/riscv/vector/vstate_prctl.c  | 266 ++++++++++++---------
>  9 files changed, 324 insertions(+), 191 deletions(-)
> 
> diff --git a/tools/testing/selftests/riscv/abi/ptrace b/tools/testing/selftests/riscv/abi/ptrace
> new file mode 100755
> index 000000000000..2b03e77b4dcf
> Binary files /dev/null and b/tools/testing/selftests/riscv/abi/ptrace differ
> diff --git a/tools/testing/selftests/riscv/vector/.gitignore b/tools/testing/selftests/riscv/vector/.gitignore
> index 9ae7964491d5..7d9c87cd0649 100644
> --- a/tools/testing/selftests/riscv/vector/.gitignore
> +++ b/tools/testing/selftests/riscv/vector/.gitignore
> @@ -1,3 +1,4 @@
>  vstate_exec_nolibc
>  vstate_prctl
> -v_initval_nolibc
> +v_initval
> +v_exec_initval_nolibc
> diff --git a/tools/testing/selftests/riscv/vector/Makefile b/tools/testing/selftests/riscv/vector/Makefile
> index bfff0ff4f3be..995746359477 100644
> --- a/tools/testing/selftests/riscv/vector/Makefile
> +++ b/tools/testing/selftests/riscv/vector/Makefile
> @@ -2,18 +2,27 @@
>  # Copyright (C) 2021 ARM Limited
>  # Originally tools/testing/arm64/abi/Makefile
>  
> -TEST_GEN_PROGS := vstate_prctl v_initval_nolibc
> -TEST_GEN_PROGS_EXTENDED := vstate_exec_nolibc
> +TEST_GEN_PROGS := v_initval vstate_prctl
> +TEST_GEN_PROGS_EXTENDED := vstate_exec_nolibc v_exec_initval_nolibc sys_hwprobe.o v_helpers.o
>  
>  include ../../lib.mk
>  
> -$(OUTPUT)/vstate_prctl: vstate_prctl.c ../hwprobe/sys_hwprobe.S
> +$(OUTPUT)/sys_hwprobe.o: ../hwprobe/sys_hwprobe.S
> +	$(CC) -static -c -o$@ $(CFLAGS) $^
> +
> +$(OUTPUT)/v_helpers.o: v_helpers.c
> +	$(CC) -static -c -o$@ $(CFLAGS) $^
> +
> +$(OUTPUT)/vstate_prctl: vstate_prctl.c $(OUTPUT)/sys_hwprobe.o $(OUTPUT)/v_helpers.o
>  	$(CC) -static -o$@ $(CFLAGS) $(LDFLAGS) $^
>  
>  $(OUTPUT)/vstate_exec_nolibc: vstate_exec_nolibc.c
>  	$(CC) -nostdlib -static -include ../../../../include/nolibc/nolibc.h \
>  		-Wall $(CFLAGS) $(LDFLAGS) $^ -o $@ -lgcc
>  
> -$(OUTPUT)/v_initval_nolibc: v_initval_nolibc.c
> +$(OUTPUT)/v_initval: v_initval.c $(OUTPUT)/sys_hwprobe.o $(OUTPUT)/v_helpers.o
> +	$(CC) -static -o$@ $(CFLAGS) $(LDFLAGS) $^
> +
> +$(OUTPUT)/v_exec_initval_nolibc: v_exec_initval_nolibc.c
>  	$(CC) -nostdlib -static -include ../../../../include/nolibc/nolibc.h \
>  		-Wall $(CFLAGS) $(LDFLAGS) $^ -o $@ -lgcc
> diff --git a/tools/testing/selftests/riscv/vector/v_exec_initval_nolibc.c b/tools/testing/selftests/riscv/vector/v_exec_initval_nolibc.c
> new file mode 100644
> index 000000000000..74b13806baf0
> --- /dev/null
> +++ b/tools/testing/selftests/riscv/vector/v_exec_initval_nolibc.c
> @@ -0,0 +1,84 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Get values of vector registers as soon as the program starts to test if
> + * is properly cleaning the values before starting a new program. Vector
> + * registers are caller saved, so no function calls may happen before reading
> + * the values. To further ensure consistency, this file is compiled without
> + * libc and without auto-vectorization.
> + *
> + * To be "clean" all values must be either all ones or all zeroes.
> + */
> +
> +#define __stringify_1(x...)	#x
> +#define __stringify(x...)	__stringify_1(x)
> +
> +int main(int argc, char **argv)
> +{
> +	char prev_value = 0, value;
> +	unsigned long vl;
> +	int first = 1;
> +
> +	asm volatile (
> +		".option push\n\t"
> +		".option arch, +v\n\t"
> +		"vsetvli	%[vl], x0, e8, m1, ta, ma\n\t"
> +		".option pop\n\t"
> +		: [vl] "=r" (vl)
> +	);
> +
> +#define CHECK_VECTOR_REGISTER(register) ({					\
> +	for (int i = 0; i < vl; i++) {						\
> +		asm volatile (							\
> +			".option push\n\t"					\
> +			".option arch, +v\n\t"					\
> +			"vmv.x.s %0, " __stringify(register) "\n\t"		\
> +			"vsrl.vi " __stringify(register) ", " __stringify(register) ", 8\n\t" \
> +			".option pop\n\t"					\
> +			: "=r" (value));					\
> +		if (first) {							\
> +			first = 0;						\
> +		} else if (value != prev_value || !(value == 0x00 || value == 0xff)) { \
> +			printf("Register " __stringify(register) " values not clean! value: %u\n", value);	\
> +			exit(-1);						\

I think we should ensure all tests in tools/testing/selftests/riscv/ use
TAP output, exiting with ksft_finished(), or at least exit with 0 for
success. For example, vstate_exec_nolibc exits with 2 for success since
it exits with the return value of prctl(PR_RISCV_V_GET_CONTROL). And
vstate_prctl.c exits with several different negative values, which means
it'll exit with several different values around 255. To figure what went
wrong, one will have to convert those exit codes to the original negative
values in order to look them up. Having these types of inconsistent exit
values complicates QA.

Thanks,
drew