1/*
  2 * Extensible Firmware Interface
  3 *
  4 * Based on Extensible Firmware Interface Specification version 2.4
  5 *
  6 * Copyright (C) 2013 - 2015 Linaro Ltd.
  7 *
  8 * This program is free software; you can redistribute it and/or modify
  9 * it under the terms of the GNU General Public License version 2 as
 10 * published by the Free Software Foundation.
 11 *
 12 */
 13
 14#include <linux/efi.h>
 15#include <linux/init.h>
 16#include <linux/memblock.h>
 17#include <linux/mm_types.h>
 18#include <linux/of.h>
 19#include <linux/of_fdt.h>
 20
 21#include <asm/efi.h>
 22
 23struct efi_memory_map memmap;
 24
 25u64 efi_system_table;
 26
 27static int __init is_normal_ram(efi_memory_desc_t *md)
 28{
 29	if (md->attribute & EFI_MEMORY_WB)
 30		return 1;
 31	return 0;
 32}
 33
 34/*
 35 * Translate a EFI virtual address into a physical address: this is necessary,
 36 * as some data members of the EFI system table are virtually remapped after
 37 * SetVirtualAddressMap() has been called.
 38 */
 39static phys_addr_t efi_to_phys(unsigned long addr)
 40{
 41	efi_memory_desc_t *md;
 42
 43	for_each_efi_memory_desc(&memmap, md) {
 44		if (!(md->attribute & EFI_MEMORY_RUNTIME))
 45			continue;
 46		if (md->virt_addr == 0)
 47			/* no virtual mapping has been installed by the stub */
 48			break;
 49		if (md->virt_addr <= addr &&
 50		    (addr - md->virt_addr) < (md->num_pages << EFI_PAGE_SHIFT))
 51			return md->phys_addr + addr - md->virt_addr;
 52	}
 53	return addr;
 54}
 55
 56static int __init uefi_init(void)
 57{
 58	efi_char16_t *c16;
 59	void *config_tables;
 60	size_t table_size;
 61	char vendor[100] = "unknown";
 62	int i, retval;
 63
 64	efi.systab = early_memremap_ro(efi_system_table,
 65				       sizeof(efi_system_table_t));
 66	if (efi.systab == NULL) {
 67		pr_warn("Unable to map EFI system table.\n");
 68		return -ENOMEM;
 69	}
 70
 71	set_bit(EFI_BOOT, &efi.flags);
 72	if (IS_ENABLED(CONFIG_64BIT))
 73		set_bit(EFI_64BIT, &efi.flags);
 74
 75	/*
 76	 * Verify the EFI Table
 77	 */
 78	if (efi.systab->hdr.signature != EFI_SYSTEM_TABLE_SIGNATURE) {
 79		pr_err("System table signature incorrect\n");
 80		retval = -EINVAL;
 81		goto out;
 82	}
 83	if ((efi.systab->hdr.revision >> 16) < 2)
 84		pr_warn("Warning: EFI system table version %d.%02d, expected 2.00 or greater\n",
 85			efi.systab->hdr.revision >> 16,
 86			efi.systab->hdr.revision & 0xffff);
 87
 88	/* Show what we know for posterity */
 89	c16 = early_memremap_ro(efi_to_phys(efi.systab->fw_vendor),
 90				sizeof(vendor) * sizeof(efi_char16_t));
 91	if (c16) {
 92		for (i = 0; i < (int) sizeof(vendor) - 1 && *c16; ++i)
 93			vendor[i] = c16[i];
 94		vendor[i] = '\0';
 95		early_memunmap(c16, sizeof(vendor) * sizeof(efi_char16_t));
 96	}
 97
 98	pr_info("EFI v%u.%.02u by %s\n",
 99		efi.systab->hdr.revision >> 16,
100		efi.systab->hdr.revision & 0xffff, vendor);
101
102	table_size = sizeof(efi_config_table_64_t) * efi.systab->nr_tables;
103	config_tables = early_memremap_ro(efi_to_phys(efi.systab->tables),
104					  table_size);
105	if (config_tables == NULL) {
106		pr_warn("Unable to map EFI config table array.\n");
107		retval = -ENOMEM;
108		goto out;
109	}
110	retval = efi_config_parse_tables(config_tables, efi.systab->nr_tables,
111					 sizeof(efi_config_table_t), NULL);
112
113	early_memunmap(config_tables, table_size);
114out:
115	early_memunmap(efi.systab,  sizeof(efi_system_table_t));
116	return retval;
117}
118
119/*
120 * Return true for RAM regions we want to permanently reserve.
121 */
122static __init int is_reserve_region(efi_memory_desc_t *md)
123{
124	switch (md->type) {
125	case EFI_LOADER_CODE:
126	case EFI_LOADER_DATA:
127	case EFI_BOOT_SERVICES_CODE:
128	case EFI_BOOT_SERVICES_DATA:
129	case EFI_CONVENTIONAL_MEMORY:
130	case EFI_PERSISTENT_MEMORY:
131		return 0;
132	default:
133		break;
134	}
135	return is_normal_ram(md);
136}
137
138static __init void reserve_regions(void)
139{
140	efi_memory_desc_t *md;
141	u64 paddr, npages, size;
142
143	if (efi_enabled(EFI_DBG))
144		pr_info("Processing EFI memory map:\n");
145
146	for_each_efi_memory_desc(&memmap, md) {
147		paddr = md->phys_addr;
148		npages = md->num_pages;
149
150		if (efi_enabled(EFI_DBG)) {
151			char buf[64];
152
153			pr_info("  0x%012llx-0x%012llx %s",
154				paddr, paddr + (npages << EFI_PAGE_SHIFT) - 1,
155				efi_md_typeattr_format(buf, sizeof(buf), md));
156		}
157
158		memrange_efi_to_native(&paddr, &npages);
159		size = npages << PAGE_SHIFT;
160
161		if (is_normal_ram(md))
162			early_init_dt_add_memory_arch(paddr, size);
163
164		if (is_reserve_region(md)) {
165			memblock_mark_nomap(paddr, size);
166			if (efi_enabled(EFI_DBG))
167				pr_cont("*");
168		}
169
170		if (efi_enabled(EFI_DBG))
171			pr_cont("\n");
172	}
173
174	set_bit(EFI_MEMMAP, &efi.flags);
175}
176
177void __init efi_init(void)
178{
179	struct efi_fdt_params params;
180
181	/* Grab UEFI information placed in FDT by stub */
182	if (!efi_get_fdt_params(&params))
183		return;
184
185	efi_system_table = params.system_table;
186
187	memmap.phys_map = params.mmap;
188	memmap.map = early_memremap_ro(params.mmap, params.mmap_size);
189	if (memmap.map == NULL) {
190		/*
191		* If we are booting via UEFI, the UEFI memory map is the only
192		* description of memory we have, so there is little point in
193		* proceeding if we cannot access it.
194		*/
195		panic("Unable to map EFI memory map.\n");
196	}
197	memmap.map_end = memmap.map + params.mmap_size;
198	memmap.desc_size = params.desc_size;
199	memmap.desc_version = params.desc_ver;
200
201	if (uefi_init() < 0)
202		return;
203
204	reserve_regions();
205	early_memunmap(memmap.map, params.mmap_size);
206
207	if (IS_ENABLED(CONFIG_ARM)) {
208		/*
209		 * ARM currently does not allow ioremap_cache() to be called on
210		 * memory regions that are covered by struct page. So remove the
211		 * UEFI memory map from the linear mapping.
212		 */
213		memblock_mark_nomap(params.mmap & PAGE_MASK,
214				    PAGE_ALIGN(params.mmap_size +
215					       (params.mmap & ~PAGE_MASK)));
216	} else {
217		memblock_reserve(params.mmap & PAGE_MASK,
218				 PAGE_ALIGN(params.mmap_size +
219					    (params.mmap & ~PAGE_MASK)));
220	}
221}