// 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 <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 ARRAY_SIZE(a) (sizeof(a) / sizeof(a[0]))

#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;
};


static struct vec_data vec_data[] = {
        {
                .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",
        },
};

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\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 *f;
        int ret;

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

        fprintf(f, "%d", val);
        fclose(f);
        if (ret < 0) {
                ksft_test_result_fail("Error writing %d to %s\n",
                                      val, name);
                return -1;
        }

        return 0;
}

/*
 * Verify that we can read the default VL via proc, checking that it
 * is set in a freshly spawned child.
 */
static void proc_read_default(struct vec_data *data)
{
        int default_vl, child_vl, ret;

        ret = file_read_integer(data->default_vl_file, &default_vl);
        if (ret != 0)
                return;

        /* Is this the actual default seen by new processes? */
        child_vl = get_child_rdvl(data);
        if (child_vl != default_vl) {
                ksft_test_result_fail("%s is %d but child VL is %d\n",
                                      data->default_vl_file,
                                      default_vl, child_vl);
                return;
        }

        ksft_test_result_pass("%s default vector length %d\n", data->name,
                              default_vl);
        data->default_vl = default_vl;
}

/* Verify that we can write a minimum value and have it take effect */
static void proc_write_min(struct vec_data *data)
{
        int ret, new_default, child_vl;

        if (geteuid() != 0) {
                ksft_test_result_skip("Need to be root to write to /proc\n");
                return;
        }

        ret = file_write_integer(data->default_vl_file, ARCH_MIN_VL);
        if (ret != 0)
                return;

        /* What was the new value? */
        ret = file_read_integer(data->default_vl_file, &new_default);
        if (ret != 0)
                return;

        /* Did it take effect in a new process? */
        child_vl = get_child_rdvl(data);
        if (child_vl != new_default) {
                ksft_test_result_fail("%s is %d but child VL is %d\n",
                                      data->default_vl_file,
                                      new_default, child_vl);
                return;
        }

        ksft_test_result_pass("%s minimum vector length %d\n", data->name,
                              new_default);
        data->min_vl = new_default;

        file_write_integer(data->default_vl_file, data->default_vl);
}

/* Verify that we can write a maximum value and have it take effect */
static void proc_write_max(struct vec_data *data)
{
        int ret, new_default, child_vl;

        if (geteuid() != 0) {
                ksft_test_result_skip("Need to be root to write to /proc\n");
                return;
        }

        /* -1 is accepted by the /proc interface as the maximum VL */
        ret = file_write_integer(data->default_vl_file, -1);
        if (ret != 0)
                return;

        /* What was the new value? */
        ret = file_read_integer(data->default_vl_file, &new_default);
        if (ret != 0)
                return;

        /* Did it take effect in a new process? */
        child_vl = get_child_rdvl(data);
        if (child_vl != new_default) {
                ksft_test_result_fail("%s is %d but child VL is %d\n",
                                      data->default_vl_file,
                                      new_default, child_vl);
                return;
        }

        ksft_test_result_pass("%s maximum vector length %d\n", data->name,
                              new_default);
        data->max_vl = new_default;

        file_write_integer(data->default_vl_file, data->default_vl);
}

/* Can we read back a VL from prctl? */
static void prctl_get(struct vec_data *data)
{
        int ret;

        ret = prctl(data->prctl_get);
        if (ret == -1) {
                ksft_test_result_fail("%s prctl() read failed: %d (%s)\n",
                                      data->name, errno, strerror(errno));
                return;
        }

        /* Mask out any flags */
        ret &= PR_SVE_VL_LEN_MASK;

        /* Is that what we can read back directly? */
        if (ret == data->rdvl())
                ksft_test_result_pass("%s current VL is %d\n",
                                      data->name, ret);
        else
                ksft_test_result_fail("%s prctl() VL %d but RDVL is %d\n",
                                      data->name, ret, data->rdvl());
}

/* Does the prctl let us set the VL we already have? */
static void prctl_set_same(struct vec_data *data)
{
        int cur_vl = data->rdvl();
        int ret;

        ret = prctl(data->prctl_set, cur_vl);
        if (ret < 0) {
                ksft_test_result_fail("%s prctl set failed: %d (%s)\n",
                                      data->name, errno, strerror(errno));
                return;
        }

        if (cur_vl != data->rdvl())
                ksft_test_result_pass("%s current VL is %d\n",
                                      data->name, ret);
        else
                ksft_test_result_fail("%s prctl() VL %d but RDVL is %d\n",
                                      data->name, ret, data->rdvl());
}

/* Can we set a new VL for this process? */
static void prctl_set(struct vec_data *data)
{
        int ret;

        if (data->min_vl == data->max_vl) {
                ksft_test_result_skip("%s only one VL supported\n",
                                      data->name);
                return;
        }

        /* Try to set the minimum VL */
        ret = prctl(data->prctl_set, data->min_vl);
        if (ret < 0) {
                ksft_test_result_fail("%s prctl set failed for %d: %d (%s)\n",
                                      data->name, data->min_vl,
                                      errno, strerror(errno));
                return;
        }

        if ((ret & PR_SVE_VL_LEN_MASK) != data->min_vl) {
                ksft_test_result_fail("%s prctl set %d but return value is %d\n",
                                      data->name, data->min_vl, data->rdvl());
                return;
        }

        if (data->rdvl() != data->min_vl) {
                ksft_test_result_fail("%s set %d but RDVL is %d\n",
                                      data->name, data->min_vl, data->rdvl());
                return;
        }

        /* Try to set the maximum VL */
        ret = prctl(data->prctl_set, data->max_vl);
        if (ret < 0) {
                ksft_test_result_fail("%s prctl set failed for %d: %d (%s)\n",
                                      data->name, data->max_vl,
                                      errno, strerror(errno));
                return;
        }

        if ((ret & PR_SVE_VL_LEN_MASK) != data->max_vl) {
                ksft_test_result_fail("%s prctl() set %d but return value is %d\n",
                                      data->name, data->max_vl, data->rdvl());
                return;
        }

        /* The _INHERIT flag should not be present when we read the VL */
        ret = prctl(data->prctl_get);
        if (ret == -1) {
                ksft_test_result_fail("%s prctl() read failed: %d (%s)\n",
                                      data->name, errno, strerror(errno));
                return;
        }

        if (ret & PR_SVE_VL_INHERIT) {
                ksft_test_result_fail("%s prctl() reports _INHERIT\n",
                                      data->name);
                return;
        }

        ksft_test_result_pass("%s prctl() set min/max\n", data->name);
}

/* If we didn't request it a new VL shouldn't affect the child */
static void prctl_set_no_child(struct vec_data *data)
{
        int ret, child_vl;

        if (data->min_vl == data->max_vl) {
                ksft_test_result_skip("%s only one VL supported\n",
                                      data->name);
                return;
        }

        ret = prctl(data->prctl_set, data->min_vl);
        if (ret < 0) {
                ksft_test_result_fail("%s prctl set failed for %d: %d (%s)\n",
                                      data->name, data->min_vl,
                                      errno, strerror(errno));
                return;
        }

        /* Ensure the default VL is different */
        ret = file_write_integer(data->default_vl_file, data->max_vl);
        if (ret != 0)
                return;

        /* Check that the child has the default we just set */
        child_vl = get_child_rdvl(data);
        if (child_vl != data->max_vl) {
                ksft_test_result_fail("%s is %d but child VL is %d\n",
                                      data->default_vl_file,
                                      data->max_vl, child_vl);
                return;
        }

        ksft_test_result_pass("%s vector length used default\n", data->name);

        file_write_integer(data->default_vl_file, data->default_vl);
}

/* If we didn't request it a new VL shouldn't affect the child */
static void prctl_set_for_child(struct vec_data *data)
{
        int ret, child_vl;

        if (data->min_vl == data->max_vl) {
                ksft_test_result_skip("%s only one VL supported\n",
                                      data->name);
                return;
        }

        ret = prctl(data->prctl_set, data->min_vl | PR_SVE_VL_INHERIT);
        if (ret < 0) {
                ksft_test_result_fail("%s prctl set failed for %d: %d (%s)\n",
                                      data->name, data->min_vl,
                                      errno, strerror(errno));
                return;
        }

        /* The _INHERIT flag should be present when we read the VL */
        ret = prctl(data->prctl_get);
        if (ret == -1) {
                ksft_test_result_fail("%s prctl() read failed: %d (%s)\n",
                                      data->name, errno, strerror(errno));
                return;
        }
        if (!(ret & PR_SVE_VL_INHERIT)) {
                ksft_test_result_fail("%s prctl() does not report _INHERIT\n",
                                      data->name);
                return;
        }

        /* Ensure the default VL is different */
        ret = file_write_integer(data->default_vl_file, data->max_vl);
        if (ret != 0)
                return;

        /* Check that the child inherited our VL */
        child_vl = get_child_rdvl(data);
        if (child_vl != data->min_vl) {
                ksft_test_result_fail("%s is %d but child VL is %d\n",
                                      data->default_vl_file,
                                      data->min_vl, child_vl);
                return;
        }

        ksft_test_result_pass("%s vector length was inherited\n", data->name);

        file_write_integer(data->default_vl_file, data->default_vl);
}

/* _ONEXEC takes effect only in the child process */
static void prctl_set_onexec(struct vec_data *data)
{
        int ret, child_vl;

        if (data->min_vl == data->max_vl) {
                ksft_test_result_skip("%s only one VL supported\n",
                                      data->name);
                return;
        }

        /* Set a known value for the default and our current VL */
        ret = file_write_integer(data->default_vl_file, data->max_vl);
        if (ret != 0)
                return;

        ret = prctl(data->prctl_set, data->max_vl);
        if (ret < 0) {
                ksft_test_result_fail("%s prctl set failed for %d: %d (%s)\n",
                                      data->name, data->min_vl,
                                      errno, strerror(errno));
                return;
        }

        /* Set a different value for the child to have on exec */
        ret = prctl(data->prctl_set, data->min_vl | PR_SVE_SET_VL_ONEXEC);
        if (ret < 0) {
                ksft_test_result_fail("%s prctl set failed for %d: %d (%s)\n",
                                      data->name, data->min_vl,
                                      errno, strerror(errno));
                return;
        }

        /* Our current VL should stay the same */
        if (data->rdvl() != data->max_vl) {
                ksft_test_result_fail("%s VL changed by _ONEXEC prctl()\n",
                                      data->name);
                return;
        }

        /* Check that the child inherited our VL */
        child_vl = get_child_rdvl(data);
        if (child_vl != data->min_vl) {
                ksft_test_result_fail("Set %d _ONEXEC but child VL is %d\n",
                                      data->min_vl, child_vl);
                return;
        }

        ksft_test_result_pass("%s vector length set on exec\n", data->name);

        file_write_integer(data->default_vl_file, data->default_vl);
}

typedef void (*test_type)(struct vec_data *);

static const test_type tests[] = {
        /*
         * The default/min/max tests must be first and in this order
         * to provide data for other tests.
         */
        proc_read_default,
        proc_write_min,
        proc_write_max,

        prctl_get,
        prctl_set,
        prctl_set_no_child,
        prctl_set_for_child,
        prctl_set_onexec,
};

int main(void)
{
        int i, j;

        ksft_print_header();
        ksft_set_plan(ARRAY_SIZE(tests) * ARRAY_SIZE(vec_data));

        for (i = 0; i < ARRAY_SIZE(vec_data); i++) {
                struct vec_data *data = &vec_data[i];
                unsigned long supported;

                supported = getauxval(data->hwcap_type) & data->hwcap;

                for (j = 0; j < ARRAY_SIZE(tests); j++) {
                        if (supported)
                                tests[j](data);
                        else
                                ksft_test_result_skip("%s not supported\n",
                                                      data->name);
                }
        }

        ksft_exit_pass();
}