Orange Pi5 kernel

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * PowerNV OPAL Dump Interface
 *
 * Copyright 2013,2014 IBM Corp.
 */
 
#include <linux/kobject.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <linux/pagemap.h>
#include <linux/delay.h>
#include <linux/interrupt.h>
 
#include <asm/opal.h>
 
#define DUMP_TYPE_FSP	0x01
 
struct dump_obj {
<------>struct kobject  kobj;
<------>struct bin_attribute dump_attr;
<------>uint32_t	id;  /* becomes object name */
<------>uint32_t	type;
<------>uint32_t	size;
<------>char		*buffer;
};
#define to_dump_obj(x) container_of(x, struct dump_obj, kobj)
 
struct dump_attribute {
<------>struct attribute attr;
<------>ssize_t (*show)(struct dump_obj *dump, struct dump_attribute *attr,
<------><------><------>char *buf);
<------>ssize_t (*store)(struct dump_obj *dump, struct dump_attribute *attr,
<------><------><------> const char *buf, size_t count);
};
#define to_dump_attr(x) container_of(x, struct dump_attribute, attr)
 
static ssize_t dump_id_show(struct dump_obj *dump_obj,
<------><------><------>    struct dump_attribute *attr,
<------><------><------>    char *buf)
{
<------>return sprintf(buf, "0x%x\n", dump_obj->id);
}
 
static const char* dump_type_to_string(uint32_t type)
{
<------>switch (type) {
<------>case 0x01: return "SP Dump";
<------>case 0x02: return "System/Platform Dump";
<------>case 0x03: return "SMA Dump";
<------>default: return "unknown";
<------>}
}
 
static ssize_t dump_type_show(struct dump_obj *dump_obj,
<------><------><------>      struct dump_attribute *attr,
<------><------><------>      char *buf)
{
 
<------>return sprintf(buf, "0x%x %s\n", dump_obj->type,
<------><------>       dump_type_to_string(dump_obj->type));
}
 
static ssize_t dump_ack_show(struct dump_obj *dump_obj,
<------><------><------>     struct dump_attribute *attr,
<------><------><------>     char *buf)
{
<------>return sprintf(buf, "ack - acknowledge dump\n");
}
 
/*
 * Send acknowledgement to OPAL
 */
static int64_t dump_send_ack(uint32_t dump_id)
{
<------>int rc;
 
<------>rc = opal_dump_ack(dump_id);
<------>if (rc)
<------><------>pr_warn("%s: Failed to send ack to Dump ID 0x%x (%d)\n",
<------><------><------>__func__, dump_id, rc);
<------>return rc;
}
 
static ssize_t dump_ack_store(struct dump_obj *dump_obj,
<------><------><------>      struct dump_attribute *attr,
<------><------><------>      const char *buf,
<------><------><------>      size_t count)
{
<------>/*
<------> * Try to self remove this attribute. If we are successful,
<------> * delete the kobject itself.
<------> */
<------>if (sysfs_remove_file_self(&dump_obj->kobj, &attr->attr)) {
<------><------>dump_send_ack(dump_obj->id);
<------><------>kobject_put(&dump_obj->kobj);
<------>}
<------>return count;
}
 
/* Attributes of a dump
 * The binary attribute of the dump itself is dynamic
 * due to the dynamic size of the dump
 */
static struct dump_attribute id_attribute =
<------>__ATTR(id, 0444, dump_id_show, NULL);
static struct dump_attribute type_attribute =
<------>__ATTR(type, 0444, dump_type_show, NULL);
static struct dump_attribute ack_attribute =
<------>__ATTR(acknowledge, 0660, dump_ack_show, dump_ack_store);
 
static ssize_t init_dump_show(struct dump_obj *dump_obj,
<------><------><------>      struct dump_attribute *attr,
<------><------><------>      char *buf)
{
<------>return sprintf(buf, "1 - initiate Service Processor(FSP) dump\n");
}
 
static int64_t dump_fips_init(uint8_t type)
{
<------>int rc;
 
<------>rc = opal_dump_init(type);
<------>if (rc)
<------><------>pr_warn("%s: Failed to initiate FSP dump (%d)\n",
<------><------><------>__func__, rc);
<------>return rc;
}
 
static ssize_t init_dump_store(struct dump_obj *dump_obj,
<------><------><------>       struct dump_attribute *attr,
<------><------><------>       const char *buf,
<------><------><------>       size_t count)
{
<------>int rc;
 
<------>rc = dump_fips_init(DUMP_TYPE_FSP);
<------>if (rc == OPAL_SUCCESS)
<------><------>pr_info("%s: Initiated FSP dump\n", __func__);
 
<------>return count;
}
 
static struct dump_attribute initiate_attribute =
<------>__ATTR(initiate_dump, 0600, init_dump_show, init_dump_store);
 
static struct attribute *initiate_attrs[] = {
<------>&initiate_attribute.attr,
<------>NULL,
};
 
static struct attribute_group initiate_attr_group = {
<------>.attrs = initiate_attrs,
};
 
static struct kset *dump_kset;
 
static ssize_t dump_attr_show(struct kobject *kobj,
<------><------><------>      struct attribute *attr,
<------><------><------>      char *buf)
{
<------>struct dump_attribute *attribute;
<------>struct dump_obj *dump;
 
<------>attribute = to_dump_attr(attr);
<------>dump = to_dump_obj(kobj);
 
<------>if (!attribute->show)
<------><------>return -EIO;
 
<------>return attribute->show(dump, attribute, buf);
}
 
static ssize_t dump_attr_store(struct kobject *kobj,
<------><------><------>       struct attribute *attr,
<------><------><------>       const char *buf, size_t len)
{
<------>struct dump_attribute *attribute;
<------>struct dump_obj *dump;
 
<------>attribute = to_dump_attr(attr);
<------>dump = to_dump_obj(kobj);
 
<------>if (!attribute->store)
<------><------>return -EIO;
 
<------>return attribute->store(dump, attribute, buf, len);
}
 
static const struct sysfs_ops dump_sysfs_ops = {
<------>.show = dump_attr_show,
<------>.store = dump_attr_store,
};
 
static void dump_release(struct kobject *kobj)
{
<------>struct dump_obj *dump;
 
<------>dump = to_dump_obj(kobj);
<------>vfree(dump->buffer);
<------>kfree(dump);
}
 
static struct attribute *dump_default_attrs[] = {
<------>&id_attribute.attr,
<------>&type_attribute.attr,
<------>&ack_attribute.attr,
<------>NULL,
};
 
static struct kobj_type dump_ktype = {
<------>.sysfs_ops = &dump_sysfs_ops,
<------>.release = &dump_release,
<------>.default_attrs = dump_default_attrs,
};
 
static int64_t dump_read_info(uint32_t *dump_id, uint32_t *dump_size, uint32_t *dump_type)
{
<------>__be32 id, size, type;
<------>int rc;
 
<------>type = cpu_to_be32(0xffffffff);
 
<------>rc = opal_dump_info2(&id, &size, &type);
<------>if (rc == OPAL_PARAMETER)
<------><------>rc = opal_dump_info(&id, &size);
 
<------>if (rc) {
<------><------>pr_warn("%s: Failed to get dump info (%d)\n",
<------><------><------>__func__, rc);
<------><------>return rc;
<------>}
 
<------>*dump_id = be32_to_cpu(id);
<------>*dump_size = be32_to_cpu(size);
<------>*dump_type = be32_to_cpu(type);
 
<------>return rc;
}
 
static int64_t dump_read_data(struct dump_obj *dump)
{
<------>struct opal_sg_list *list;
<------>uint64_t addr;
<------>int64_t rc;
 
<------>/* Allocate memory */
<------>dump->buffer = vzalloc(PAGE_ALIGN(dump->size));
<------>if (!dump->buffer) {
<------><------>pr_err("%s : Failed to allocate memory\n", __func__);
<------><------>rc = -ENOMEM;
<------><------>goto out;
<------>}
 
<------>/* Generate SG list */
<------>list = opal_vmalloc_to_sg_list(dump->buffer, dump->size);
<------>if (!list) {
<------><------>rc = -ENOMEM;
<------><------>goto out;
<------>}
 
<------>/* First entry address */
<------>addr = __pa(list);
 
<------>/* Fetch data */
<------>rc = OPAL_BUSY_EVENT;
<------>while (rc == OPAL_BUSY || rc == OPAL_BUSY_EVENT) {
<------><------>rc = opal_dump_read(dump->id, addr);
<------><------>if (rc == OPAL_BUSY_EVENT) {
<------><------><------>opal_poll_events(NULL);
<------><------><------>msleep(20);
<------><------>}
<------>}
 
<------>if (rc != OPAL_SUCCESS && rc != OPAL_PARTIAL)
<------><------>pr_warn("%s: Extract dump failed for ID 0x%x\n",
<------><------><------>__func__, dump->id);
 
<------>/* Free SG list */
<------>opal_free_sg_list(list);
 
out:
<------>return rc;
}
 
static ssize_t dump_attr_read(struct file *filep, struct kobject *kobj,
<------><------><------>      struct bin_attribute *bin_attr,
<------><------><------>      char *buffer, loff_t pos, size_t count)
{
<------>ssize_t rc;
 
<------>struct dump_obj *dump = to_dump_obj(kobj);
 
<------>if (!dump->buffer) {
<------><------>rc = dump_read_data(dump);
 
<------><------>if (rc != OPAL_SUCCESS && rc != OPAL_PARTIAL) {
<------><------><------>vfree(dump->buffer);
<------><------><------>dump->buffer = NULL;
 
<------><------><------>return -EIO;
<------><------>}
<------><------>if (rc == OPAL_PARTIAL) {
<------><------><------>/* On a partial read, we just return EIO
<------><------><------> * and rely on userspace to ask us to try
<------><------><------> * again.
<------><------><------> */
<------><------><------>pr_info("%s: Platform dump partially read. ID = 0x%x\n",
<------><------><------><------>__func__, dump->id);
<------><------><------>return -EIO;
<------><------>}
<------>}
 
<------>memcpy(buffer, dump->buffer + pos, count);
 
<------>/* You may think we could free the dump buffer now and retrieve
<------> * it again later if needed, but due to current firmware limitation,
<------> * that's not the case. So, once read into userspace once,
<------> * we keep the dump around until it's acknowledged by userspace.
<------> */
 
<------>return count;
}
 
static void create_dump_obj(uint32_t id, size_t size, uint32_t type)
{
<------>struct dump_obj *dump;
<------>int rc;
 
<------>dump = kzalloc(sizeof(*dump), GFP_KERNEL);
<------>if (!dump)
<------><------>return;
 
<------>dump->kobj.kset = dump_kset;
 
<------>kobject_init(&dump->kobj, &dump_ktype);
 
<------>sysfs_bin_attr_init(&dump->dump_attr);
 
<------>dump->dump_attr.attr.name = "dump";
<------>dump->dump_attr.attr.mode = 0400;
<------>dump->dump_attr.size = size;
<------>dump->dump_attr.read = dump_attr_read;
 
<------>dump->id = id;
<------>dump->size = size;
<------>dump->type = type;
 
<------>rc = kobject_add(&dump->kobj, NULL, "0x%x-0x%x", type, id);
<------>if (rc) {
<------><------>kobject_put(&dump->kobj);
<------><------>return;
<------>}
 
<------>/*
<------> * As soon as the sysfs file for this dump is created/activated there is
<------> * a chance the opal_errd daemon (or any userspace) might read and
<------> * acknowledge the dump before kobject_uevent() is called. If that
<------> * happens then there is a potential race between
<------> * dump_ack_store->kobject_put() and kobject_uevent() which leads to a
<------> * use-after-free of a kernfs object resulting in a kernel crash.
<------> *
<------> * To avoid that, we need to take a reference on behalf of the bin file,
<------> * so that our reference remains valid while we call kobject_uevent().
<------> * We then drop our reference before exiting the function, leaving the
<------> * bin file to drop the last reference (if it hasn't already).
<------> */
 
<------>/* Take a reference for the bin file */
<------>kobject_get(&dump->kobj);
<------>rc = sysfs_create_bin_file(&dump->kobj, &dump->dump_attr);
<------>if (rc == 0) {
<------><------>kobject_uevent(&dump->kobj, KOBJ_ADD);
 
<------><------>pr_info("%s: New platform dump. ID = 0x%x Size %u\n",
<------><------><------>__func__, dump->id, dump->size);
<------>} else {
<------><------>/* Drop reference count taken for bin file */
<------><------>kobject_put(&dump->kobj);
<------>}
 
<------>/* Drop our reference */
<------>kobject_put(&dump->kobj);
<------>return;
}
 
static irqreturn_t process_dump(int irq, void *data)
{
<------>int rc;
<------>uint32_t dump_id, dump_size, dump_type;
<------>char name[22];
<------>struct kobject *kobj;
 
<------>rc = dump_read_info(&dump_id, &dump_size, &dump_type);
<------>if (rc != OPAL_SUCCESS)
<------><------>return IRQ_HANDLED;
 
<------>sprintf(name, "0x%x-0x%x", dump_type, dump_id);
 
<------>/* we may get notified twice, let's handle
<------> * that gracefully and not create two conflicting
<------> * entries.
<------> */
<------>kobj = kset_find_obj(dump_kset, name);
<------>if (kobj) {
<------><------>/* Drop reference added by kset_find_obj() */
<------><------>kobject_put(kobj);
<------><------>return IRQ_HANDLED;
<------>}
 
<------>create_dump_obj(dump_id, dump_size, dump_type);
 
<------>return IRQ_HANDLED;
}
 
void __init opal_platform_dump_init(void)
{
<------>int rc;
<------>int dump_irq;
 
<------>/* ELOG not supported by firmware */
<------>if (!opal_check_token(OPAL_DUMP_READ))
<------><------>return;
 
<------>dump_kset = kset_create_and_add("dump", NULL, opal_kobj);
<------>if (!dump_kset) {
<------><------>pr_warn("%s: Failed to create dump kset\n", __func__);
<------><------>return;
<------>}
 
<------>rc = sysfs_create_group(&dump_kset->kobj, &initiate_attr_group);
<------>if (rc) {
<------><------>pr_warn("%s: Failed to create initiate dump attr group\n",
<------><------><------>__func__);
<------><------>kobject_put(&dump_kset->kobj);
<------><------>return;
<------>}
 
<------>dump_irq = opal_event_request(ilog2(OPAL_EVENT_DUMP_AVAIL));
<------>if (!dump_irq) {
<------><------>pr_err("%s: Can't register OPAL event irq (%d)\n",
<------><------>       __func__, dump_irq);
<------><------>return;
<------>}
 
<------>rc = request_threaded_irq(dump_irq, NULL, process_dump,
<------><------><------><------>IRQF_TRIGGER_HIGH | IRQF_ONESHOT,
<------><------><------><------>"opal-dump", NULL);
<------>if (rc) {
<------><------>pr_err("%s: Can't request OPAL event irq (%d)\n",
<------><------>       __func__, rc);
<------><------>return;
<------>}
 
<------>if (opal_check_token(OPAL_DUMP_RESEND))
<------><------>opal_dump_resend_notification();
}