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, 2014 Linaro Ltd.
  8 */
  9
 10#include <linux/dmi.h>
 11#include <linux/efi.h>
 12#include <linux/io.h>
 13#include <linux/memblock.h>
 14#include <linux/mm_types.h>
 15#include <linux/preempt.h>
 16#include <linux/rbtree.h>
 17#include <linux/rwsem.h>
 18#include <linux/sched.h>
 19#include <linux/slab.h>
 20#include <linux/spinlock.h>
 21
 22#include <asm/cacheflush.h>
 23#include <asm/efi.h>
 24#include <asm/mmu.h>
 25#include <asm/pgalloc.h>
 26#include <asm/pgtable.h>
 27
 28extern u64 efi_system_table;
 29
 30#ifdef CONFIG_ARM64_PTDUMP_DEBUGFS
 31#include <asm/ptdump.h>
 32
 33static struct ptdump_info efi_ptdump_info = {
 34	.mm		= &efi_mm,
 35	.markers	= (struct addr_marker[]){
 36		{ 0,				"UEFI runtime start" },
 37		{ DEFAULT_MAP_WINDOW_64,	"UEFI runtime end" },
 38		{ -1,				NULL }
 39	},
 40	.base_addr	= 0,
 41};
 42
 43static int __init ptdump_init(void)
 44{
 45	if (efi_enabled(EFI_RUNTIME_SERVICES))
 46		ptdump_debugfs_register(&efi_ptdump_info, "efi_page_tables");
 47
 48	return 0;
 49}
 50device_initcall(ptdump_init);
 51
 52#endif
 53
 54static bool __init efi_virtmap_init(void)
 55{
 56	efi_memory_desc_t *md;
 57	bool systab_found;
 58
 59	efi_mm.pgd = pgd_alloc(&efi_mm);
 60	mm_init_cpumask(&efi_mm);
 61	init_new_context(NULL, &efi_mm);
 62
 63	systab_found = false;
 64	for_each_efi_memory_desc(md) {
 65		phys_addr_t phys = md->phys_addr;
 66		int ret;
 67
 68		if (!(md->attribute & EFI_MEMORY_RUNTIME))
 69			continue;
 70		if (md->virt_addr == 0)
 71			return false;
 72
 73		ret = efi_create_mapping(&efi_mm, md);
 74		if (ret) {
 75			pr_warn("  EFI remap %pa: failed to create mapping (%d)\n",
 76				&phys, ret);
 77			return false;
 78		}
 79		/*
 80		 * If this entry covers the address of the UEFI system table,
 81		 * calculate and record its virtual address.
 82		 */
 83		if (efi_system_table >= phys &&
 84		    efi_system_table < phys + (md->num_pages * EFI_PAGE_SIZE)) {
 85			efi.systab = (void *)(unsigned long)(efi_system_table -
 86							     phys + md->virt_addr);
 87			systab_found = true;
 88		}
 89	}
 90	if (!systab_found) {
 91		pr_err("No virtual mapping found for the UEFI System Table\n");
 92		return false;
 93	}
 94
 95	if (efi_memattr_apply_permissions(&efi_mm, efi_set_mapping_permissions))
 96		return false;
 97
 98	return true;
 99}
100
101/*
102 * Enable the UEFI Runtime Services if all prerequisites are in place, i.e.,
103 * non-early mapping of the UEFI system table and virtual mappings for all
104 * EFI_MEMORY_RUNTIME regions.
105 */
106static int __init arm_enable_runtime_services(void)
107{
108	u64 mapsize;
109
110	if (!efi_enabled(EFI_BOOT)) {
111		pr_info("EFI services will not be available.\n");
112		return 0;
113	}
114
115	efi_memmap_unmap();
116
117	mapsize = efi.memmap.desc_size * efi.memmap.nr_map;
118
119	if (efi_memmap_init_late(efi.memmap.phys_map, mapsize)) {
120		pr_err("Failed to remap EFI memory map\n");
121		return 0;
122	}
123
124	if (efi_runtime_disabled()) {
125		pr_info("EFI runtime services will be disabled.\n");
126		return 0;
127	}
128
129	if (efi_enabled(EFI_RUNTIME_SERVICES)) {
130		pr_info("EFI runtime services access via paravirt.\n");
131		return 0;
132	}
133
134	pr_info("Remapping and enabling EFI services.\n");
135
136	if (!efi_virtmap_init()) {
137		pr_err("UEFI virtual mapping missing or invalid -- runtime services will not be available\n");
138		return -ENOMEM;
139	}
140
141	/* Set up runtime services function pointers */
142	efi_native_runtime_setup();
143	set_bit(EFI_RUNTIME_SERVICES, &efi.flags);
144
145	return 0;
146}
147early_initcall(arm_enable_runtime_services);
148
149void efi_virtmap_load(void)
150{
151	preempt_disable();
152	efi_set_pgd(&efi_mm);
153}
154
155void efi_virtmap_unload(void)
156{
157	efi_set_pgd(current->active_mm);
158	preempt_enable();
159}
160
161
162static int __init arm_dmi_init(void)
163{
164	/*
165	 * On arm64/ARM, DMI depends on UEFI, and dmi_setup() needs to
166	 * be called early because dmi_id_init(), which is an arch_initcall
167	 * itself, depends on dmi_scan_machine() having been called already.
168	 */
169	dmi_setup();
170	return 0;
171}
172core_initcall(arm_dmi_init);