1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Common EFI memory map functions.
4 */
5
6 #define pr_fmt(fmt) "efi: " fmt
7
8 #include <linux/init.h>
9 #include <linux/kernel.h>
10 #include <linux/efi.h>
11 #include <linux/io.h>
12 #include <linux/memblock.h>
13 #include <linux/slab.h>
14
15 #include <asm/early_ioremap.h>
16 #include <asm/efi.h>
17
18 #ifndef __efi_memmap_free
19 #define __efi_memmap_free(phys, size, flags) do { } while (0)
20 #endif
21
22 /**
23 * __efi_memmap_init - Common code for mapping the EFI memory map
24 * @data: EFI memory map data
25 *
26 * This function takes care of figuring out which function to use to
27 * map the EFI memory map in efi.memmap based on how far into the boot
28 * we are.
29 *
30 * During bootup EFI_MEMMAP_LATE in data->flags should be clear since we
31 * only have access to the early_memremap*() functions as the vmalloc
32 * space isn't setup. Once the kernel is fully booted we can fallback
33 * to the more robust memremap*() API.
34 *
35 * Returns: zero on success, a negative error code on failure.
36 */
__efi_memmap_init(struct efi_memory_map_data * data)37 int __init __efi_memmap_init(struct efi_memory_map_data *data)
38 {
39 struct efi_memory_map map;
40 phys_addr_t phys_map;
41
42 phys_map = data->phys_map;
43
44 if (data->flags & EFI_MEMMAP_LATE)
45 map.map = memremap(phys_map, data->size, MEMREMAP_WB);
46 else
47 map.map = early_memremap(phys_map, data->size);
48
49 if (!map.map) {
50 pr_err("Could not map the memory map!\n");
51 return -ENOMEM;
52 }
53
54 if (efi.memmap.flags & (EFI_MEMMAP_MEMBLOCK | EFI_MEMMAP_SLAB))
55 __efi_memmap_free(efi.memmap.phys_map,
56 efi.memmap.desc_size * efi.memmap.nr_map,
57 efi.memmap.flags);
58
59 map.phys_map = data->phys_map;
60 map.nr_map = data->size / data->desc_size;
61 map.map_end = map.map + data->size;
62
63 map.desc_version = data->desc_version;
64 map.desc_size = data->desc_size;
65 map.flags = data->flags;
66
67 set_bit(EFI_MEMMAP, &efi.flags);
68
69 efi.memmap = map;
70
71 return 0;
72 }
73
74 /**
75 * efi_memmap_init_early - Map the EFI memory map data structure
76 * @data: EFI memory map data
77 *
78 * Use early_memremap() to map the passed in EFI memory map and assign
79 * it to efi.memmap.
80 *
81 * Returns: zero on success, a negative error code on failure.
82 */
efi_memmap_init_early(struct efi_memory_map_data * data)83 int __init efi_memmap_init_early(struct efi_memory_map_data *data)
84 {
85 /* Cannot go backwards */
86 WARN_ON(efi.memmap.flags & EFI_MEMMAP_LATE);
87
88 data->flags = 0;
89 return __efi_memmap_init(data);
90 }
91
efi_memmap_unmap(void)92 void __init efi_memmap_unmap(void)
93 {
94 if (!efi_enabled(EFI_MEMMAP))
95 return;
96
97 if (!(efi.memmap.flags & EFI_MEMMAP_LATE)) {
98 unsigned long size;
99
100 size = efi.memmap.desc_size * efi.memmap.nr_map;
101 early_memunmap(efi.memmap.map, size);
102 } else {
103 memunmap(efi.memmap.map);
104 }
105
106 efi.memmap.map = NULL;
107 clear_bit(EFI_MEMMAP, &efi.flags);
108 }
109
110 /**
111 * efi_memmap_init_late - Map efi.memmap with memremap()
112 * @addr: Physical address of the new EFI memory map
113 * @size: Size in bytes of the new EFI memory map
114 *
115 * Setup a mapping of the EFI memory map using ioremap_cache(). This
116 * function should only be called once the vmalloc space has been
117 * setup and is therefore not suitable for calling during early EFI
118 * initialise, e.g. in efi_init(). Additionally, it expects
119 * efi_memmap_init_early() to have already been called.
120 *
121 * The reason there are two EFI memmap initialisation
122 * (efi_memmap_init_early() and this late version) is because the
123 * early EFI memmap should be explicitly unmapped once EFI
124 * initialisation is complete as the fixmap space used to map the EFI
125 * memmap (via early_memremap()) is a scarce resource.
126 *
127 * This late mapping is intended to persist for the duration of
128 * runtime so that things like efi_mem_desc_lookup() and
129 * efi_mem_attributes() always work.
130 *
131 * Returns: zero on success, a negative error code on failure.
132 */
efi_memmap_init_late(phys_addr_t addr,unsigned long size)133 int __init efi_memmap_init_late(phys_addr_t addr, unsigned long size)
134 {
135 struct efi_memory_map_data data = {
136 .phys_map = addr,
137 .size = size,
138 .flags = EFI_MEMMAP_LATE,
139 };
140
141 /* Did we forget to unmap the early EFI memmap? */
142 WARN_ON(efi.memmap.map);
143
144 /* Were we already called? */
145 WARN_ON(efi.memmap.flags & EFI_MEMMAP_LATE);
146
147 /*
148 * It makes no sense to allow callers to register different
149 * values for the following fields. Copy them out of the
150 * existing early EFI memmap.
151 */
152 data.desc_version = efi.memmap.desc_version;
153 data.desc_size = efi.memmap.desc_size;
154
155 return __efi_memmap_init(&data);
156 }
157