path: root/tools/testing/selftests/arm64/fp/vec-syscfg.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2021 ARM Limited.
 * Original author: Mark Brown <broonie@kernel.org>
 */
#include <assert.h>
#include <errno.h>
#include <fcntl.h>
#include <stdbool.h>
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/auxv.h>
#include <sys/prctl.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <asm/sigcontext.h>
#include <asm/hwcap.h>

#include "kselftest.h"
#include "rdvl.h"

#define ARCH_MIN_VL SVE_VL_MIN

struct vec_data {
	const char *name;
	unsigned long hwcap_type;
	unsigned long hwcap;
	const char *rdvl_binary;
	int (*rdvl)(void);

	int prctl_get;
	int prctl_set;
	const char *default_vl_file;

	int default_vl;
	int min_vl;
	int max_vl;
};

#define VEC_SVE 0
#define VEC_SME 1

static struct vec_data vec_data[] = {
	[VEC_SVE] = {
		.name = "SVE",
		.hwcap_type = AT_HWCAP,
		.hwcap = HWCAP_SVE,
		.rdvl = rdvl_sve,
		.rdvl_binary = "./rdvl-sve",
		.prctl_get = PR_SVE_GET_VL,
		.prctl_set = PR_SVE_SET_VL,
		.default_vl_file = "/proc/sys/abi/sve_default_vector_length",
	},
	[VEC_SME] = {
		.name = "SME",
		.hwcap_type = AT_HWCAP2,
		.hwcap = HWCAP2_SME,
		.rdvl = rdvl_sme,
		.rdvl_binary = "./rdvl-sme",
		.prctl_get = PR_SME_GET_VL,
		.prctl_set = PR_SME_SET_VL,
		.default_vl_file = "/proc/sys/abi/sme_default_vector_length",
	},
};

static bool vec_type_supported(struct vec_data *data)
{
	return getauxval(data->hwcap_type) & data->hwcap;
}

static int stdio_read_integer(FILE *f, const char *what, int *val)
{
	int n = 0;
	int ret;

	ret = fscanf(f, "%d%*1[\n]%n", val, &n);
	if (ret < 1 || n < 1) {
		ksft_print_msg("failed to parse integer from %s\n", what);
		return -1;
	}

	return 0;
}

/* Start a new process and return the vector length it sees */
static int get_child_rdvl(struct vec_data *data)
{
	FILE *out;
	int pipefd[2];
	pid_t pid, child;
	int read_vl, ret;

	ret = pipe(pipefd);
	if (ret == -1) {
		ksft_print_msg("pipe() failed: %d (%s)\n",
			       errno, strerror(errno));
		return -1;
	}

	fflush(stdout);

	child = fork();
	if (child == -1) {
		ksft_print_msg("fork() failed: %d (%s)\n",
			       errno, strerror(errno));
		close(pipefd[0]);
		close(pipefd[1]);
		return -1;
	}

	/* Child: put vector length on the pipe */
	if (child == 0) {
		/*
		 * Replace stdout with the pipe, errors to stderr from
		 * here as kselftest prints to stdout.
		 */
		ret = dup2(pipefd[1], 1);
		if (ret == -1) {
			fprintf(stderr, "dup2() %d\n", errno);
			exit(EXIT_FAILURE);
		}

		/* exec() a new binary which puts the VL on stdout */
		ret = execl(data->rdvl_binary, data->rdvl_binary, NULL);
		fprintf(stderr, "execl(%s) failed: %d (%s)\n",
			data->rdvl_binary, errno, strerror(errno));

		exit(EXIT_FAILURE);
	}

	close(pipefd[1]);

	/* Parent; wait for the exit status from the child & verify it */
	do {
		pid = wait(&ret);
		if (pid == -1) {
			ksft_print_msg("wait() failed: %d (%s)\n",
				       errno, strerror(errno));
			close(pipefd[0]);
			return -1;
		}
	} while (pid != child);

	assert(pid == child);

	if (!WIFEXITED(ret)) {
		ksft_print_msg("child exited abnormally\n");
		close(pipefd[0]);
		return -1;
	}

	if (WEXITSTATUS(ret) != 0) {
		ksft_print_msg("child returned error %d\n",
			       WEXITSTATUS(ret));
		close(pipefd[0]);
		return -1;
	}

	out = fdopen(pipefd[0], "r");
	if (!out) {
		ksft_print_msg("failed to open child stdout\n");
		close(pipefd[0]);
		return -1;
	}

	ret = stdio_read_integer(out, "child", &read_vl);
	fclose(out);
	if (ret != 0)
		return ret;

	return read_vl;
}

static int file_read_integer(const char *name, int *val)
{
	FILE *f;
	int ret;

	f = fopen(name, "r");
	if (!f) {
		ksft_test_result_fail("Unable to open %s: %d (%s)\n",
				      name, errno,
				      strerror(errno));
		return -1;
	}

	ret = stdio_read_integer(f, name, val);
	fclose(f);

	return ret;
}

static int file_write_integer(const char *name, int val)
{
	FILE