// SPDX-License-Identifier: GPL-2.0-only/* * coreboot_table.c * * Module providing coreboot table access. * * Copyright 2017 Google Inc. * Copyright 2017 Samuel Holland <samuel@sholland.org> */ #include <linux/acpi.h>#include <linux/device.h>#include <linux/err.h>#include <linux/init.h>#include <linux/io.h>#include <linux/ioport.h>#include <linux/kernel.h>#include <linux/device-id/coreboot.h>#include <linux/mm.h>#include <linux/module.h>#include <linux/of.h>#include <linux/platform_device.h>#include <linux/slab.h> #include "coreboot_table.h" /* Coreboot table header structure */struct coreboot_table_header {	char signature[4];	u32 header_bytes;	u32 header_checksum;	u32 table_bytes;	u32 table_checksum;	u32 table_entries;}; #define CB_DEV(d) container_of(d, struct coreboot_device, dev)#define CB_DRV(d) container_of_const(d, struct coreboot_driver, drv) static int coreboot_bus_match(struct device *dev, const struct device_driver *drv){	struct coreboot_device *device = CB_DEV(dev);	const struct coreboot_driver *driver = CB_DRV(drv);	const struct coreboot_device_id *id; 	if (!driver->id_table)		return 0; 	for (id = driver->id_table; id->tag; id++) {		if (device->entry.tag == id->tag)			return 1;	} 	return 0;} static int coreboot_bus_probe(struct device *dev){	int ret = -ENODEV;	struct coreboot_device *device = CB_DEV(dev);	struct coreboot_driver *driver = CB_DRV(dev->driver); 	if (driver->probe)		ret = driver->probe(device); 	return ret;} static void coreboot_bus_remove(struct device *dev){	struct coreboot_device *device = CB_DEV(dev);	struct coreboot_driver *driver = CB_DRV(dev->driver); 	if (driver->remove)		driver->remove(device);} static int coreboot_bus_uevent(const struct device *dev, struct kobj_uevent_env *env){	struct coreboot_device *device = CB_DEV(dev);	u32 tag = device->entry.tag; 	return add_uevent_var(env, "MODALIAS=coreboot:t%08X", tag);} static const struct bus_type coreboot_bus_type = {	.name		= "coreboot",	.match		= coreboot_bus_match,	.probe		= coreboot_bus_probe,	.remove		= coreboot_bus_remove,	.uevent		= coreboot_bus_uevent,}; static void coreboot_device_release(struct device *dev){	struct coreboot_device *device = CB_DEV(dev); 	kfree(device);} int __coreboot_driver_register(struct coreboot_driver *driver,			       struct module *owner){	driver->drv.bus = &coreboot_bus_type;	driver->drv.owner = owner; 	return driver_register(&driver->drv);}EXPORT_SYMBOL(__coreboot_driver_register); void coreboot_driver_unregister(struct coreboot_driver *driver){	driver_unregister(&driver->drv);}EXPORT_SYMBOL(coreboot_driver_unregister); static int coreboot_table_populate(struct device *dev, void *ptr, resource_size_t len){	int i, ret;	void *ptr_entry;	struct coreboot_device *device;	struct coreboot_table_entry *entry;	struct coreboot_table_header *header = ptr;	void *ptr_end; 	ptr_end = ptr + len;	ptr_entry = ptr + header->header_bytes;	for (i = 0; i < header->table_entries; i++, ptr_entry += entry->size) {		if (ptr_entry + sizeof(*entry) > ptr_end)			return -EINVAL;		entry = ptr_entry; 		if (entry->size < sizeof(*entry)) {			dev_warn(dev, "coreboot table entry too small!\n");			return -EINVAL;		} 		if (ptr_entry + entry->size > ptr_end)			return -EINVAL; 		device = kzalloc(sizeof(device->dev) + entry->size, GFP_KERNEL);		if (!device)			return -ENOMEM; 		device->dev.parent = dev;		device->dev.bus = &coreboot_bus_type;		device->dev.release = coreboot_device_release;		memcpy(device->raw, ptr_entry, entry->size); 		switch (device->entry.tag) {		case LB_TAG_CBMEM_ENTRY:			/*			 * Skip entries that are not exclusively System RAM or			 * Reserved memory.			 * On ARM64, no-map regions are filtered out as they are			 * IORESOURCE_MEM (see request_standard_resources() in			 * arch/arm64/kernel/setup.c).			 * On x86, CBMEM often resides in standard reserved regions			 * (IORES_DESC_RESERVED).			 */			if (region_intersects(device->cbmem_entry.address,					      device->cbmem_entry.entry_size,					      IORESOURCE_SYSTEM_RAM,					      IORES_DESC_NONE) != REGION_INTERSECTS &&			    region_intersects(device->cbmem_entry.address,					      device->cbmem_entry.entry_size,					      IORESOURCE_MEM,					      IORES_DESC_RESERVED) != REGION_INTERSECTS) {				kfree(device);				continue;			}			dev_set_name(&device->dev, "cbmem-%08x",				     device->cbmem_entry.id);			break;		default:			dev_set_name(&device->dev, "coreboot%d", i);			break;		} 		ret = device_register(&device->dev);		if (ret) {			dev_warn(dev, "failed to register coreboot device: %d\n", ret);			put_device(&device->dev);		}	} 	return 0;} static int coreboot_table_probe(struct platform_device *pdev){	resource_size_t len;	resource_size_t table_span;	struct coreboot_table_header *header;	struct resource *res;	struct device *dev = &pdev->dev;	void *ptr;	int ret; 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);	if (!res)		return -EINVAL; 	len = resource_size(res);	if (!res->start || len < sizeof(*header))		return -EINVAL; 	/* Check just the header first to make sure things are sane */	header = memremap(res->start, sizeof(*header), MEMREMAP_WB);	if (!header)		return -ENOMEM; 	ret = strncmp(header->signature, "LBIO", sizeof(header->signature)); 	if (!ret &&	    (header->header_bytes < sizeof(*header) ||	     check_add_overflow((resource_size_t)header->header_bytes,				(resource_size_t)header->table_bytes,				&table_span) ||	     table_span > len))		ret = -EINVAL; 	memunmap(header);	if (ret) {		dev_warn(dev, "coreboot table missing or corrupt!\n");		return -ENODEV;	} 	ptr = memremap(res->start, table_span, MEMREMAP_WB);	if (!ptr)		return -ENOMEM; 	ret = coreboot_table_populate(dev, ptr, table_span); 	memunmap(ptr); 	return ret;} static int __cb_dev_unregister(struct device *dev, void *dummy){	device_unregister(dev);	return 0;} static void coreboot_table_remove(struct platform_device *pdev){	bus_for_each_dev(&coreboot_bus_type, NULL, NULL, __cb_dev_unregister);} #ifdef CONFIG_ACPIstatic const struct acpi_device_id cros_coreboot_acpi_match[] = {	{ "GOOGCB00", 0 },	{ "BOOT0000", 0 },	{ }};MODULE_DEVICE_TABLE(acpi, cros_coreboot_acpi_match);#endif #ifdef CONFIG_OFstatic const struct of_device_id coreboot_of_match[] = {	{ .compatible = "coreboot" },	{}};MODULE_DEVICE_TABLE(of, coreboot_of_match);#endif static struct platform_driver coreboot_table_driver = {	.probe = coreboot_table_probe,	.remove = coreboot_table_remove,	.driver = {		.name = "coreboot_table",		.acpi_match_table = ACPI_PTR(cros_coreboot_acpi_match),		.of_match_table = of_match_ptr(coreboot_of_match),	},}; static int __init coreboot_table_driver_init(void){	int ret; 	ret = bus_register(&coreboot_bus_type);	if (ret)		return ret; 	ret = platform_driver_register(&coreboot_table_driver);	if (ret) {		bus_unregister(&coreboot_bus_type);		return ret;	} 	return 0;} static void __exit coreboot_table_driver_exit(void){	platform_driver_unregister(&coreboot_table_driver);	bus_unregister(&coreboot_bus_type);} subsys_initcall(coreboot_table_driver_init);module_exit(coreboot_table_driver_exit); MODULE_AUTHOR("Google, Inc.");MODULE_DESCRIPTION("Module providing coreboot table access");MODULE_LICENSE("GPL");