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/fwnode.h>
 14#include <linux/init.h>
 15#include <linux/memblock.h>
 16#include <linux/mm_types.h>
 17#include <linux/of.h>
 18#include <linux/of_address.h>
 19#include <linux/of_fdt.h>
 20#include <linux/platform_device.h>
 21#include <linux/screen_info.h>
 22
 23#include <asm/efi.h>
 24
 25unsigned long __initdata screen_info_table = EFI_INVALID_TABLE_ADDR;
 26
 27static int __init is_memory(efi_memory_desc_t *md)
 28{
 29	if (md->attribute & (EFI_MEMORY_WB|EFI_MEMORY_WT|EFI_MEMORY_WC))
 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 __init efi_to_phys(unsigned long addr)
 40{
 41	efi_memory_desc_t *md;
 42
 43	for_each_efi_memory_desc(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
 56extern __weak const efi_config_table_type_t efi_arch_tables[];
 57
 58static void __init init_screen_info(void)
 59{
 60	struct screen_info *si;
 61
 62	if (screen_info_table != EFI_INVALID_TABLE_ADDR) {
 63		si = early_memremap(screen_info_table, sizeof(*si));
 64		if (!si) {
 65			pr_err("Could not map screen_info config table\n");
 66			return;
 67		}
 68		screen_info = *si;
 69		memset(si, 0, sizeof(*si));
 70		early_memunmap(si, sizeof(*si));
 71
 72		if (memblock_is_map_memory(screen_info.lfb_base))
 73			memblock_mark_nomap(screen_info.lfb_base,
 74					    screen_info.lfb_size);
 75	}
 76}
 77
 78static int __init uefi_init(u64 efi_system_table)
 79{
 80	efi_config_table_t *config_tables;
 81	efi_system_table_t *systab;
 82	size_t table_size;
 83	int retval;
 84
 85	systab = early_memremap_ro(efi_system_table, sizeof(efi_system_table_t));
 86	if (systab == NULL) {
 87		pr_warn("Unable to map EFI system table.\n");
 88		return -ENOMEM;
 89	}
 90
 91	set_bit(EFI_BOOT, &efi.flags);
 92	if (IS_ENABLED(CONFIG_64BIT))
 93		set_bit(EFI_64BIT, &efi.flags);
 94
 95	retval = efi_systab_check_header(&systab->hdr, 2);
 96	if (retval)
 97		goto out;
 98
 99	efi.runtime = systab->runtime;
100	efi.runtime_version = systab->hdr.revision;
101
102	efi_systab_report_header(&systab->hdr, efi_to_phys(systab->fw_vendor));
103
104	table_size = sizeof(efi_config_table_t) * systab->nr_tables;
105	config_tables = early_memremap_ro(efi_to_phys(systab->tables),
106					  table_size);
107	if (config_tables == NULL) {
108		pr_warn("Unable to map EFI config table array.\n");
109		retval = -ENOMEM;
110		goto out;
111	}
112	retval = efi_config_parse_tables(config_tables, systab->nr_tables,
113					 efi_arch_tables);
114
115	early_memunmap(config_tables, table_size);
116out:
117	early_memunmap(systab, sizeof(efi_system_table_t));
118	return retval;
119}
120
121/*
122 * Return true for regions that can be used as System RAM.
123 */
124static __init int is_usable_memory(efi_memory_desc_t *md)
125{
126	switch (md->type) {
127	case EFI_LOADER_CODE:
128	case EFI_LOADER_DATA:
129	case EFI_ACPI_RECLAIM_MEMORY:
130	case EFI_BOOT_SERVICES_CODE:
131	case EFI_BOOT_SERVICES_DATA:
132	case EFI_CONVENTIONAL_MEMORY:
133	case EFI_PERSISTENT_MEMORY:
134		/*
135		 * Special purpose memory is 'soft reserved', which means it
136		 * is set aside initially, but can be hotplugged back in or
137		 * be assigned to the dax driver after boot.
138		 */
139		if (efi_soft_reserve_enabled() &&
140		    (md->attribute & EFI_MEMORY_SP))
141			return false;
142
143		/*
144		 * According to the spec, these regions are no longer reserved
145		 * after calling ExitBootServices(). However, we can only use
146		 * them as System RAM if they can be mapped writeback cacheable.
147		 */
148		return (md->attribute & EFI_MEMORY_WB);
149	default:
150		break;
151	}
152	return false;
153}
154
155static __init void reserve_regions(void)
156{
157	efi_memory_desc_t *md;
158	u64 paddr, npages, size;
159
160	if (efi_enabled(EFI_DBG))
161		pr_info("Processing EFI memory map:\n");
162
163	/*
164	 * Discard memblocks discovered so far: if there are any at this
165	 * point, they originate from memory nodes in the DT, and UEFI
166	 * uses its own memory map instead.
167	 */
168	memblock_dump_all();
169	memblock_remove(0, PHYS_ADDR_MAX);
170
171	for_each_efi_memory_desc(md) {
172		paddr = md->phys_addr;
173		npages = md->num_pages;
174
175		if (efi_enabled(EFI_DBG)) {
176			char buf[64];
177
178			pr_info("  0x%012llx-0x%012llx %s\n",
179				paddr, paddr + (npages << EFI_PAGE_SHIFT) - 1,
180				efi_md_typeattr_format(buf, sizeof(buf), md));
181		}
182
183		memrange_efi_to_native(&paddr, &npages);
184		size = npages << PAGE_SHIFT;
185
186		if (is_memory(md)) {
187			early_init_dt_add_memory_arch(paddr, size);
188
189			if (!is_usable_memory(md))
190				memblock_mark_nomap(paddr, size);
191
192			/* keep ACPI reclaim memory intact for kexec etc. */
193			if (md->type == EFI_ACPI_RECLAIM_MEMORY)
194				memblock_reserve(paddr, size);
195		}
196	}
197}
198
199void __init efi_init(void)
200{
201	struct efi_memory_map_data data;
202	u64 efi_system_table;
203
204	/* Grab UEFI information placed in FDT by stub */
205	efi_system_table = efi_get_fdt_params(&data);
206	if (!efi_system_table)
207		return;
208
209	if (efi_memmap_init_early(&data) < 0) {
210		/*
211		* If we are booting via UEFI, the UEFI memory map is the only
212		* description of memory we have, so there is little point in
213		* proceeding if we cannot access it.
214		*/
215		panic("Unable to map EFI memory map.\n");
216	}
217
218	WARN(efi.memmap.desc_version != 1,
219	     "Unexpected EFI_MEMORY_DESCRIPTOR version %ld",
220	      efi.memmap.desc_version);
221
222	if (uefi_init(efi_system_table) < 0) {
223		efi_memmap_unmap();
224		return;
225	}
226
227	reserve_regions();
228	/*
229	 * For memblock manipulation, the cap should come after the memblock_add().
230	 * And now, memblock is fully populated, it is time to do capping.
231	 */
232	early_init_dt_check_for_usable_mem_range();
233	efi_find_mirror();
234	efi_esrt_init();
235	efi_mokvar_table_init();
236
237	memblock_reserve(data.phys_map & PAGE_MASK,
238			 PAGE_ALIGN(data.size + (data.phys_map & ~PAGE_MASK)));
239
240	init_screen_info();
241}