1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * Extensible Firmware Interface
  4 *
  5 * Based on Extensible Firmware Interface Specification version 2.4
  6 *
  7 * Copyright (C) 2013 - 2015 Linaro Ltd.
  8 */
  9
 10#define pr_fmt(fmt)	"efi: " fmt
 11
 12#include <linux/efi.h>
 13#include <linux/init.h>
 14#include <linux/memblock.h>
 15#include <linux/mm_types.h>
 16#include <linux/of.h>
 17#include <linux/of_fdt.h>
 18#include <linux/platform_device.h>
 19#include <linux/screen_info.h>
 20
 21#include <asm/efi.h>
 22
 23u64 efi_system_table;
 24
 25static int __init is_memory(efi_memory_desc_t *md)
 26{
 27	if (md->attribute & (EFI_MEMORY_WB|EFI_MEMORY_WT|EFI_MEMORY_WC))
 28		return 1;
 29	return 0;
 30}
 31
 32/*
 33 * Translate a EFI virtual address into a physical address: this is necessary,
 34 * as some data members of the EFI system table are virtually remapped after
 35 * SetVirtualAddressMap() has been called.
 36 */
 37static phys_addr_t efi_to_phys(unsigned long addr)
 38{
 39	efi_memory_desc_t *md;
 40
 41	for_each_efi_memory_desc(md) {
 42		if (!(md->attribute & EFI_MEMORY_RUNTIME))
 43			continue;
 44		if (md->virt_addr == 0)
 45			/* no virtual mapping has been installed by the stub */
 46			break;
 47		if (md->virt_addr <= addr &&
 48		    (addr - md->virt_addr) < (md->num_pages << EFI_PAGE_SHIFT))
 49			return md->phys_addr + addr - md->virt_addr;
 50	}
 51	return addr;
 52}
 53
 54static __initdata unsigned long screen_info_table = EFI_INVALID_TABLE_ADDR;
 55
 56static __initdata efi_config_table_type_t arch_tables[] = {
 57	{LINUX_EFI_ARM_SCREEN_INFO_TABLE_GUID, NULL, &screen_info_table},
 58	{NULL_GUID, NULL, NULL}
 59};
 60
 61static void __init init_screen_info(void)
 62{
 63	struct screen_info *si;
 64
 65	if (screen_info_table != EFI_INVALID_TABLE_ADDR) {
 66		si = early_memremap_ro(screen_info_table, sizeof(*si));
 67		if (!si) {
 68			pr_err("Could not map screen_info config table\n");
 69			return;
 70		}
 71		screen_info = *si;
 72		early_memunmap(si, sizeof(*si));
 73
 74		/* dummycon on ARM needs non-zero values for columns/lines */
 75		screen_info.orig_video_cols = 80;
 76		screen_info.orig_video_lines = 25;
 77	}
 78
 79	if (screen_info.orig_video_isVGA == VIDEO_TYPE_EFI &&
 80	    memblock_is_map_memory(screen_info.lfb_base))
 81		memblock_mark_nomap(screen_info.lfb_base, screen_info.lfb_size);
 82}
 83
 84static int __init uefi_init(void)
 85{
 86	efi_char16_t *c16;
 87	void *config_tables;
 88	size_t table_size;
 89	char vendor[100] = "unknown";
 90	int i, retval;
 91
 92	efi.systab = early_memremap_ro(efi_system_table,
 93				       sizeof(efi_system_table_t));
 94	if (efi.systab == NULL) {
 95		pr_warn("Unable to map EFI system table.\n");
 96		return -ENOMEM;
 97	}
 98
 99	set_bit(EFI_BOOT, &efi.flags);
100	if (IS_ENABLED(CONFIG_64BIT))
101		set_bit(EFI_64BIT, &efi.flags);
102
103	/*
104	 * Verify the EFI Table
105	 */
106	if (efi.systab->hdr.signature != EFI_SYSTEM_TABLE_SIGNATURE) {
107		pr_err("System table signature incorrect\n");
108		retval = -EINVAL;
109		goto out;
110	}
111	if ((efi.systab->hdr.revision >> 16) < 2)
112		pr_warn("Warning: EFI system table version %d.%02d, expected 2.00 or greater\n",
113			efi.systab->hdr.revision >> 16,
114			efi.systab->hdr.revision & 0xffff);
115
116	efi.runtime_version = efi.systab->hdr.revision;
117
118	/* Show what we know for posterity */
119	c16 = early_memremap_ro(efi_to_phys(efi.systab->fw_vendor),
120				sizeof(vendor) * sizeof(efi_char16_t));
121	if (c16) {
122		for (i = 0; i < (int) sizeof(vendor) - 1 && *c16; ++i)
123			vendor[i] = c16[i];
124		vendor[i] = '\0';
125		early_memunmap(c16, sizeof(vendor) * sizeof(efi_char16_t));
126	}
127
128	pr_info("EFI v%u.%.02u by %s\n",
129		efi.systab->hdr.revision >> 16,
130		efi.systab->hdr.revision & 0xffff, vendor);
131
132	table_size = sizeof(efi_config_table_64_t) * efi.systab->nr_tables;
133	config_tables = early_memremap_ro(efi_to_phys(efi.systab->tables),
134					  table_size);
135	if (config_tables == NULL) {
136		pr_warn("Unable to map EFI config table array.\n");
137		retval = -ENOMEM;
138		goto out;
139	}
140	retval = efi_config_parse_tables(config_tables, efi.systab->nr_tables,
141					 sizeof(efi_config_table_t),
142					 arch_tables);
143
144	if (!retval)
145		efi.config_table = (unsigned long)efi.systab->tables;
146
147	early_memunmap(config_tables, table_size);
148out:
149	early_memunmap(efi.systab,  sizeof(efi_system_table_t));
150	return retval;
151}
152
153/*
154 * Return true for regions that can be used as System RAM.
155 */
156static __init int is_usable_memory(efi_memory_desc_t *md)
157{
158	switch (md->type) {
159	case EFI_LOADER_CODE:
160	case EFI_LOADER_DATA:
161	case EFI_ACPI_RECLAIM_MEMORY:
162	case EFI_BOOT_SERVICES_CODE:
163	case EFI_BOOT_SERVICES_DATA:
164	case EFI_CONVENTIONAL_MEMORY:
165	case EFI_PERSISTENT_MEMORY:
166		/*
167		 * According to the spec, these regions are no longer reserved
168		 * after calling ExitBootServices(). However, we can only use
169		 * them as System RAM if they can be mapped writeback cacheable.
170		 */
171		return (md->attribute & EFI_MEMORY_WB);
172	default:
173		break;
174	}
175	return false;
176}
177
178static __init void reserve_regions(void)
179{
180	efi_memory_desc_t *md;
181	u64 paddr, npages, size;
182
183	if (efi_enabled(EFI_DBG))
184		pr_info("Processing EFI memory map:\n");
185
186	/*
187	 * Discard memblocks discovered so far: if there are any at this
188	 * point, they originate from memory nodes in the DT, and UEFI
189	 * uses its own memory map instead.
190	 */
191	memblock_dump_all();
192	memblock_remove(0, PHYS_ADDR_MAX);
193
194	for_each_efi_memory_desc(md) {
195		paddr = md->phys_addr;
196		npages = md->num_pages;
197
198		if (efi_enabled(EFI_DBG)) {
199			char buf[64];
200
201			pr_info("  0x%012llx-0x%012llx %s\n",
202				paddr, paddr + (npages << EFI_PAGE_SHIFT) - 1,
203				efi_md_typeattr_format(buf, sizeof(buf), md));
204		}
205
206		memrange_efi_to_native(&paddr, &npages);
207		size = npages << PAGE_SHIFT;
208
209		if (is_memory(md)) {
210			early_init_dt_add_memory_arch(paddr, size);
211
212			if (!is_usable_memory(md))
213				memblock_mark_nomap(paddr, size);
214
215			/* keep ACPI reclaim memory intact for kexec etc. */
216			if (md->type == EFI_ACPI_RECLAIM_MEMORY)
217				memblock_reserve(paddr, size);
218		}
219	}
220}
221
222void __init efi_init(void)
223{
224	struct efi_memory_map_data data;
225	struct efi_fdt_params params;
226
227	/* Grab UEFI information placed in FDT by stub */
228	if (!efi_get_fdt_params(&params))
229		return;
230
231	efi_system_table = params.system_table;
232
233	data.desc_version = params.desc_ver;
234	data.desc_size = params.desc_size;
235	data.size = params.mmap_size;
236	data.phys_map = params.mmap;
237
238	if (efi_memmap_init_early(&data) < 0) {
239		/*
240		* If we are booting via UEFI, the UEFI memory map is the only
241		* description of memory we have, so there is little point in
242		* proceeding if we cannot access it.
243		*/
244		panic("Unable to map EFI memory map.\n");
245	}
246
247	WARN(efi.memmap.desc_version != 1,
248	     "Unexpected EFI_MEMORY_DESCRIPTOR version %ld",
249	      efi.memmap.desc_version);
250
251	if (uefi_init() < 0) {
252		efi_memmap_unmap();
253		return;
254	}
255
256	reserve_regions();
257	efi_esrt_init();
258
259	memblock_reserve(params.mmap & PAGE_MASK,
260			 PAGE_ALIGN(params.mmap_size +
261				    (params.mmap & ~PAGE_MASK)));
262
263	init_screen_info();
264
265	/* ARM does not permit early mappings to persist across paging_init() */
266	if (IS_ENABLED(CONFIG_ARM))
267		efi_memmap_unmap();
268}
269
270static int __init register_gop_device(void)
271{
272	void *pd;
273
274	if (screen_info.orig_video_isVGA != VIDEO_TYPE_EFI)
275		return 0;
276
277	pd = platform_device_register_data(NULL, "efi-framebuffer", 0,
278					   &screen_info, sizeof(screen_info));
279	return PTR_ERR_OR_ZERO(pd);
280}
281subsys_initcall(register_gop_device);