1 /*
2  * Extensible Firmware Interface
3  *
4  * Based on Extensible Firmware Interface Specification version 2.4
5  *
6  * Copyright (C) 2013, 2014 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/dmi.h>
15 #include <linux/efi.h>
16 #include <linux/io.h>
17 #include <linux/memblock.h>
18 #include <linux/mm_types.h>
19 #include <linux/preempt.h>
20 #include <linux/rbtree.h>
21 #include <linux/rwsem.h>
22 #include <linux/sched.h>
23 #include <linux/slab.h>
24 #include <linux/spinlock.h>
25 
26 #include <asm/cacheflush.h>
27 #include <asm/efi.h>
28 #include <asm/mmu.h>
29 #include <asm/pgalloc.h>
30 #include <asm/pgtable.h>
31 
32 extern u64 efi_system_table;
33 
34 #ifdef CONFIG_ARM64_PTDUMP_DEBUGFS
35 #include <asm/ptdump.h>
36 
37 static struct ptdump_info efi_ptdump_info = {
38 	.mm		= &efi_mm,
39 	.markers	= (struct addr_marker[]){
40 		{ 0,		"UEFI runtime start" },
41 		{ TASK_SIZE_64,	"UEFI runtime end" }
42 	},
43 	.base_addr	= 0,
44 };
45 
46 static int __init ptdump_init(void)
47 {
48 	if (!efi_enabled(EFI_RUNTIME_SERVICES))
49 		return 0;
50 
51 	return ptdump_debugfs_register(&efi_ptdump_info, "efi_page_tables");
52 }
53 device_initcall(ptdump_init);
54 
55 #endif
56 
57 static bool __init efi_virtmap_init(void)
58 {
59 	efi_memory_desc_t *md;
60 	bool systab_found;
61 
62 	efi_mm.pgd = pgd_alloc(&efi_mm);
63 	mm_init_cpumask(&efi_mm);
64 	init_new_context(NULL, &efi_mm);
65 
66 	systab_found = false;
67 	for_each_efi_memory_desc(md) {
68 		phys_addr_t phys = md->phys_addr;
69 		int ret;
70 
71 		if (!(md->attribute & EFI_MEMORY_RUNTIME))
72 			continue;
73 		if (md->virt_addr == 0)
74 			return false;
75 
76 		ret = efi_create_mapping(&efi_mm, md);
77 		if (ret) {
78 			pr_warn("  EFI remap %pa: failed to create mapping (%d)\n",
79 				&phys, ret);
80 			return false;
81 		}
82 		/*
83 		 * If this entry covers the address of the UEFI system table,
84 		 * calculate and record its virtual address.
85 		 */
86 		if (efi_system_table >= phys &&
87 		    efi_system_table < phys + (md->num_pages * EFI_PAGE_SIZE)) {
88 			efi.systab = (void *)(unsigned long)(efi_system_table -
89 							     phys + md->virt_addr);
90 			systab_found = true;
91 		}
92 	}
93 	if (!systab_found) {
94 		pr_err("No virtual mapping found for the UEFI System Table\n");
95 		return false;
96 	}
97 
98 	if (efi_memattr_apply_permissions(&efi_mm, efi_set_mapping_permissions))
99 		return false;
100 
101 	return true;
102 }
103 
104 /*
105  * Enable the UEFI Runtime Services if all prerequisites are in place, i.e.,
106  * non-early mapping of the UEFI system table and virtual mappings for all
107  * EFI_MEMORY_RUNTIME regions.
108  */
109 static int __init arm_enable_runtime_services(void)
110 {
111 	u64 mapsize;
112 
113 	if (!efi_enabled(EFI_BOOT) || !efi_enabled(EFI_MEMMAP)) {
114 		pr_info("EFI services will not be available.\n");
115 		return 0;
116 	}
117 
118 	efi_memmap_unmap();
119 
120 	mapsize = efi.memmap.desc_size * efi.memmap.nr_map;
121 
122 	if (efi_memmap_init_late(efi.memmap.phys_map, mapsize)) {
123 		pr_err("Failed to remap EFI memory map\n");
124 		return 0;
125 	}
126 
127 	if (efi_runtime_disabled()) {
128 		pr_info("EFI runtime services will be disabled.\n");
129 		return 0;
130 	}
131 
132 	if (efi_enabled(EFI_RUNTIME_SERVICES)) {
133 		pr_info("EFI runtime services access via paravirt.\n");
134 		return 0;
135 	}
136 
137 	pr_info("Remapping and enabling EFI services.\n");
138 
139 	if (!efi_virtmap_init()) {
140 		pr_err("UEFI virtual mapping missing or invalid -- runtime services will not be available\n");
141 		return -ENOMEM;
142 	}
143 
144 	/* Set up runtime services function pointers */
145 	efi_native_runtime_setup();
146 	set_bit(EFI_RUNTIME_SERVICES, &efi.flags);
147 
148 	return 0;
149 }
150 early_initcall(arm_enable_runtime_services);
151 
152 void efi_virtmap_load(void)
153 {
154 	preempt_disable();
155 	efi_set_pgd(&efi_mm);
156 }
157 
158 void efi_virtmap_unload(void)
159 {
160 	efi_set_pgd(current->active_mm);
161 	preempt_enable();
162 }
163 
164 
165 static int __init arm_dmi_init(void)
166 {
167 	/*
168 	 * On arm64/ARM, DMI depends on UEFI, and dmi_scan_machine() needs to
169 	 * be called early because dmi_id_init(), which is an arch_initcall
170 	 * itself, depends on dmi_scan_machine() having been called already.
171 	 */
172 	dmi_scan_machine();
173 	if (dmi_available)
174 		dmi_set_dump_stack_arch_desc();
175 	return 0;
176 }
177 core_initcall(arm_dmi_init);
178