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e5bc22a4 AB |
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/efi.h> | |
f7d92489 | 15 | #include <linux/io.h> |
e5bc22a4 AB |
16 | #include <linux/memblock.h> |
17 | #include <linux/mm_types.h> | |
18 | #include <linux/preempt.h> | |
19 | #include <linux/rbtree.h> | |
20 | #include <linux/rwsem.h> | |
21 | #include <linux/sched.h> | |
22 | #include <linux/slab.h> | |
23 | #include <linux/spinlock.h> | |
24 | ||
25 | #include <asm/cacheflush.h> | |
26 | #include <asm/efi.h> | |
e5bc22a4 | 27 | #include <asm/mmu.h> |
f7d92489 | 28 | #include <asm/pgalloc.h> |
e5bc22a4 AB |
29 | #include <asm/pgtable.h> |
30 | ||
e5bc22a4 AB |
31 | extern u64 efi_system_table; |
32 | ||
33 | static struct mm_struct efi_mm = { | |
34 | .mm_rb = RB_ROOT, | |
e5bc22a4 AB |
35 | .mm_users = ATOMIC_INIT(2), |
36 | .mm_count = ATOMIC_INIT(1), | |
37 | .mmap_sem = __RWSEM_INITIALIZER(efi_mm.mmap_sem), | |
38 | .page_table_lock = __SPIN_LOCK_UNLOCKED(efi_mm.page_table_lock), | |
39 | .mmlist = LIST_HEAD_INIT(efi_mm.mmlist), | |
40 | }; | |
41 | ||
42 | static bool __init efi_virtmap_init(void) | |
43 | { | |
44 | efi_memory_desc_t *md; | |
14c43be6 | 45 | bool systab_found; |
e5bc22a4 | 46 | |
f7d92489 | 47 | efi_mm.pgd = pgd_alloc(&efi_mm); |
e5bc22a4 AB |
48 | init_new_context(NULL, &efi_mm); |
49 | ||
14c43be6 | 50 | systab_found = false; |
e5bc22a4 | 51 | for_each_efi_memory_desc(&memmap, md) { |
f7d92489 AB |
52 | phys_addr_t phys = md->phys_addr; |
53 | int ret; | |
e5bc22a4 AB |
54 | |
55 | if (!(md->attribute & EFI_MEMORY_RUNTIME)) | |
56 | continue; | |
57 | if (md->virt_addr == 0) | |
58 | return false; | |
59 | ||
f7d92489 AB |
60 | ret = efi_create_mapping(&efi_mm, md); |
61 | if (!ret) { | |
62 | pr_info(" EFI remap %pa => %p\n", | |
63 | &phys, (void *)(unsigned long)md->virt_addr); | |
64 | } else { | |
65 | pr_warn(" EFI remap %pa: failed to create mapping (%d)\n", | |
66 | &phys, ret); | |
67 | return false; | |
68 | } | |
14c43be6 AB |
69 | /* |
70 | * If this entry covers the address of the UEFI system table, | |
71 | * calculate and record its virtual address. | |
72 | */ | |
73 | if (efi_system_table >= phys && | |
74 | efi_system_table < phys + (md->num_pages * EFI_PAGE_SIZE)) { | |
75 | efi.systab = (void *)(unsigned long)(efi_system_table - | |
76 | phys + md->virt_addr); | |
77 | systab_found = true; | |
78 | } | |
e5bc22a4 | 79 | } |
14c43be6 AB |
80 | if (!systab_found) |
81 | pr_err("No virtual mapping found for the UEFI System Table\n"); | |
82 | return systab_found; | |
e5bc22a4 AB |
83 | } |
84 | ||
85 | /* | |
86 | * Enable the UEFI Runtime Services if all prerequisites are in place, i.e., | |
87 | * non-early mapping of the UEFI system table and virtual mappings for all | |
88 | * EFI_MEMORY_RUNTIME regions. | |
89 | */ | |
f7d92489 | 90 | static int __init arm_enable_runtime_services(void) |
e5bc22a4 AB |
91 | { |
92 | u64 mapsize; | |
93 | ||
94 | if (!efi_enabled(EFI_BOOT)) { | |
95 | pr_info("EFI services will not be available.\n"); | |
96 | return 0; | |
97 | } | |
98 | ||
99 | if (efi_runtime_disabled()) { | |
100 | pr_info("EFI runtime services will be disabled.\n"); | |
101 | return 0; | |
102 | } | |
103 | ||
104 | pr_info("Remapping and enabling EFI services.\n"); | |
105 | ||
106 | mapsize = memmap.map_end - memmap.map; | |
107 | memmap.map = (__force void *)ioremap_cache(memmap.phys_map, | |
108 | mapsize); | |
109 | if (!memmap.map) { | |
110 | pr_err("Failed to remap EFI memory map\n"); | |
111 | return -ENOMEM; | |
112 | } | |
113 | memmap.map_end = memmap.map + mapsize; | |
114 | efi.memmap = &memmap; | |
115 | ||
e5bc22a4 | 116 | if (!efi_virtmap_init()) { |
14c43be6 | 117 | pr_err("UEFI virtual mapping missing or invalid -- runtime services will not be available\n"); |
e5bc22a4 AB |
118 | return -ENOMEM; |
119 | } | |
120 | ||
121 | /* Set up runtime services function pointers */ | |
122 | efi_native_runtime_setup(); | |
123 | set_bit(EFI_RUNTIME_SERVICES, &efi.flags); | |
124 | ||
e5bc22a4 AB |
125 | return 0; |
126 | } | |
f7d92489 | 127 | early_initcall(arm_enable_runtime_services); |
e5bc22a4 AB |
128 | |
129 | void efi_virtmap_load(void) | |
130 | { | |
131 | preempt_disable(); | |
132 | efi_set_pgd(&efi_mm); | |
133 | } | |
134 | ||
135 | void efi_virtmap_unload(void) | |
136 | { | |
137 | efi_set_pgd(current->active_mm); | |
138 | preempt_enable(); | |
139 | } |