// SPDX-License-Identifier: GPL-2.0-only
/*
 * Architecture specific sysfs attributes in /sys/kernel
 *
 * Copyright (C) 2007, Intel Corp.
 *      Huang Ying <ying.huang@intel.com>
 * Copyright (C) 2013, 2013 Red Hat, Inc.
 *      Dave Young <dyoung@redhat.com>
 */

#include <linux/kobject.h>
#include <linux/string.h>
#include <linux/sysfs.h>
#include <linux/init.h>
#include <linux/stat.h>
#include <linux/slab.h>
#include <linux/mm.h>
#include <linux/io.h>

#include <asm/setup.h>

static ssize_t version_show(struct kobject *kobj,
                            struct kobj_attribute *attr, char *buf)
{
        return sprintf(buf, "0x%04x\n", boot_params.hdr.version);
}

static struct kobj_attribute boot_params_version_attr = __ATTR_RO(version);

static ssize_t boot_params_data_read(struct file *fp, struct kobject *kobj,
                                     const struct bin_attribute *bin_attr,
                                     char *buf, loff_t off, size_t count)
{
        memcpy(buf, (void *)&boot_params + off, count);
        return count;
}

static const struct bin_attribute boot_params_data_attr = {
        .attr = {
                .name = "data",
                .mode = S_IRUGO,
        },
        .read = boot_params_data_read,
        .size = sizeof(boot_params),
};

static struct attribute *boot_params_version_attrs[] = {
        &boot_params_version_attr.attr,
        NULL,
};

static const struct bin_attribute *const boot_params_data_attrs[] = {
        &boot_params_data_attr,
        NULL,
};

static const struct attribute_group boot_params_attr_group = {
        .attrs = boot_params_version_attrs,
        .bin_attrs = boot_params_data_attrs,
};

static int kobj_to_setup_data_nr(struct kobject *kobj, int *nr)
{
        const char *name;

        name = kobject_name(kobj);
        return kstrtoint(name, 10, nr);
}

static int get_setup_data_paddr(int nr, u64 *paddr)
{
        int i = 0;
        struct setup_data *data;
        u64 pa_data = boot_params.hdr.setup_data;

        while (pa_data) {
                if (nr == i) {
                        *paddr = pa_data;
                        return 0;
                }
                data = memremap(pa_data, sizeof(*data), MEMREMAP_WB);
                if (!data)
                        return -ENOMEM;

                pa_data = data->next;
                memunmap(data);
                i++;
        }
        return -EINVAL;
}

static int __init get_setup_data_size(int nr, size_t *size)
{
        u64 pa_data = boot_params.hdr.setup_data, pa_next;
        struct setup_indirect *indirect;
        struct setup_data *data;
        int i = 0;
        u32 len;

        while (pa_data) {
                data = memremap(pa_data, sizeof(*data), MEMREMAP_WB);
                if (!data)
                        return -ENOMEM;
                pa_next = data->next;

                if (nr == i) {
                        if (data->type == SETUP_INDIRECT) {
                                len = sizeof(*data) + data->len;
                                memunmap(data);
                                data = memremap(pa_data, len, MEMREMAP_WB);
                                if (!data)
                                        return -ENOMEM;

                                indirect = (struct setup_indirect *)data->data;

                                if (indirect->type != SETUP_INDIRECT)
                                        *size = indirect->len;
                                else
                                        *size = data->len;
                        } else {
                                *size = data->len;
                        }

                        memunmap(data);
                        return 0;
                }

                pa_data = pa_next;
                memunmap(data);
                i++;
        }
        return -EINVAL;
}

static ssize_t type_show(struct kobject *kobj,
                         struct kobj_attribute *attr, char *buf)
{
        struct setup_indirect *indirect;
        struct setup_data *data;
        int nr, ret;
        u64 paddr;
        u32 len;

        ret = kobj_to_setup_data_nr(kobj, &nr);
        if (ret)
                return ret;

        ret = get_setup_data_paddr(nr, &paddr);
        if (ret)
                return ret;
        data = memremap(paddr, sizeof(*data), MEMREMAP_WB);
        if (!data)
                return -ENOMEM;

        if (data->type == SETUP_INDIRECT) {
                len = sizeof(*data) + data->len;
                memunmap(data);
                data = memremap(paddr, len, MEMREMAP_WB);
                if (!data)
                        return -ENOMEM;

                indirect = (struct setup_indirect *)data->data;

                ret = sprintf(buf, "0x%x\n", indirect->type);
        } else {
                ret = sprintf(buf, "0x%x\n", data->type);
        }

        memunmap(data);
        return ret;
}

static ssize_t setup_data_data_read(struct file *fp,
                                    struct kobject *kobj,
                                    const struct bin_attribute *bin_attr,
                                    char *buf,
                                    loff_t off, size_t count)
{
        struct setup_indirect *indirect;
        struct setup_data *data;
        int nr, ret = 0;
        u64 paddr, len;
        void *p;

        ret = kobj_to_setup_data_nr(kobj, &nr);
        if (ret)
                return ret;

        ret = get_setup_data_paddr(nr, &paddr);
        if (ret)
                return ret;
        data = memremap(paddr, sizeof(*data), MEMREMAP_WB);
        if (!data)
                return -ENOMEM;

        if (data->type == SETUP_INDIRECT) {
                len = sizeof(*data) + data->len;
                memunmap(data);
                data = memremap(paddr, len, MEMREMAP_WB);
                if (!data)
                        return -ENOMEM;

                indirect = (struct setup_indirect *)data->data;

                if (indirect->type != SETUP_INDIRECT) {
                        paddr = indirect->addr;
                        len = indirect->len;
                } else {
                        /*
                         * Even though this is technically undefined, return
                         * the data as though it is a normal setup_data struct.
                         * This will at least allow it to be inspected.
                         */
                        paddr += sizeof(*data);
                        len = data->len;
                }
        } else {
                paddr += sizeof(*data);
                len = data->len;
        }

        if (off > len) {
                ret = -EINVAL;
                goto out;
        }

        if (count > len - off)
                count = len - off;

        if (!count)
                goto out;

        ret = count;
        p = memremap(paddr, len, MEMREMAP_WB);
        if (!p) {
                ret = -ENOMEM;
                goto out;
        }
        memcpy(buf, p + off, count);
        memunmap(p);
out:
        memunmap(data);
        return ret;
}

static struct kobj_attribute type_attr = __ATTR_RO(type);

static struct bin_attribute data_attr __ro_after_init = {
        .attr = {
                .name = "data",
                .mode = S_IRUGO,
        },
        .read = setup_data_data_read,
};

static struct attribute *setup_data_type_attrs[] = {
        &type_attr.attr,
        NULL,
};

static const struct bin_attribute *const setup_data_data_attrs[] = {
        &data_attr,
        NULL,
};

static const struct attribute_group setup_data_attr_group = {
        .attrs = setup_data_type_attrs,
        .bin_attrs = setup_data_data_attrs,
};

static int __init create_setup_data_node(struct kobject *parent,
                                         struct kobject **kobjp, int nr)
{
        int ret = 0;
        size_t size;
        struct kobject *kobj;
        char name[16]; /* should be enough for setup_data nodes numbers */
        snprintf(name, 16, "%d", nr);

        kobj = kobject_create_and_add(name, parent);
        if (!kobj)
                return -ENOMEM;

        ret = get_setup_data_size(nr, &size);
        if (ret)
                goto out_kobj;

        data_attr.size = size;
        ret = sysfs_create_group(kobj, &setup_data_attr_group);
        if (ret)
                goto out_kobj;
        *kobjp = kobj;

        return 0;
out_kobj:
        kobject_put(kobj);
        return ret;
}

static void __init cleanup_setup_data_node(struct kobject *kobj)
{
        sysfs_remove_group(kobj, &setup_data_attr_group);
        kobject_put(kobj);
}

static int __init get_setup_data_total_num(u64 pa_data, int *nr)
{
        int ret = 0;
        struct setup_data *data;

        *nr = 0;
        while (pa_data) {
                *nr += 1;
                data = memremap(pa_data, sizeof(*data), MEMREMAP_WB);
                if (!data) {
                        ret = -ENOMEM;
                        goto out;
                }
                pa_data = data->next;
                memunmap(data);
        }

out:
        return ret;
}

static int __init create_setup_data_nodes(struct kobject *parent)
{
        struct kobject *setup_data_kobj, **kobjp;
        u64 pa_data;
        int i, j, nr, ret = 0;

        pa_data = boot_params.hdr.setup_data;
        if (!pa_data)
                return 0;

        setup_data_kobj = kobject_create_and_add("setup_data", parent);
        if (!setup_data_kobj) {
                ret = -ENOMEM;
                goto out;
        }

        ret = get_setup_data_total_num(pa_data, &nr);
        if (ret)
                goto out_setup_data_kobj;

        kobjp = kmalloc_objs(*kobjp, nr);
        if (!kobjp) {
                ret = -ENOMEM;
                goto out_setup_data_kobj;
        }

        for (i = 0; i < nr; i++) {
                ret = create_setup_data_node(setup_data_kobj, kobjp + i, i);
                if (ret)
                        goto out_clean_nodes;
        }

        kfree(kobjp);
        return 0;

out_clean_nodes:
        for (j = i - 1; j >= 0; j--)
                cleanup_setup_data_node(*(kobjp + j));
        kfree(kobjp);
out_setup_data_kobj:
        kobject_put(setup_data_kobj);
out:
        return ret;
}

static int __init boot_params_ksysfs_init(void)
{
        int ret;
        struct kobject *boot_params_kobj;

        boot_params_kobj = kobject_create_and_add("boot_params",
                                                  kernel_kobj);
        if (!boot_params_kobj) {
                ret = -ENOMEM;
                goto out;
        }

        ret = sysfs_create_group(boot_params_kobj, &boot_params_attr_group);
        if (ret)
                goto out_boot_params_kobj;

        ret = create_setup_data_nodes(boot_params_kobj);
        if (ret)
                goto out_create_group;

        return 0;
out_create_group:
        sysfs_remove_group(boot_params_kobj, &boot_params_attr_group);
out_boot_params_kobj:
        kobject_put(boot_params_kobj);
out:
        return ret;
}

arch_initcall(boot_params_ksysfs_init);