1 // SPDX-License-Identifier: GPL-2.0
3 * Common EFI memory map functions.
6 #define pr_fmt(fmt) "efi: " fmt
8 #include <linux/init.h>
9 #include <linux/kernel.h>
10 #include <linux/efi.h>
12 #include <linux/memblock.h>
13 #include <linux/slab.h>
15 #include <asm/early_ioremap.h>
18 #ifndef __efi_memmap_free
19 #define __efi_memmap_free(phys, size, flags) do { } while (0)
23 * __efi_memmap_init - Common code for mapping the EFI memory map
24 * @data: EFI memory map data
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
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.
35 * Returns: zero on success, a negative error code on failure.
37 int __init __efi_memmap_init(struct efi_memory_map_data *data)
39 struct efi_memory_map map;
42 phys_map = data->phys_map;
44 if (data->flags & EFI_MEMMAP_LATE)
45 map.map = memremap(phys_map, data->size, MEMREMAP_WB);
47 map.map = early_memremap(phys_map, data->size);
50 pr_err("Could not map the memory map!\n");
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,
59 map.phys_map = data->phys_map;
60 map.nr_map = data->size / data->desc_size;
61 map.map_end = map.map + data->size;
63 map.desc_version = data->desc_version;
64 map.desc_size = data->desc_size;
65 map.flags = data->flags;
67 set_bit(EFI_MEMMAP, &efi.flags);
75 * efi_memmap_init_early - Map the EFI memory map data structure
76 * @data: EFI memory map data
78 * Use early_memremap() to map the passed in EFI memory map and assign
81 * Returns: zero on success, a negative error code on failure.
83 int __init efi_memmap_init_early(struct efi_memory_map_data *data)
85 /* Cannot go backwards */
86 WARN_ON(efi.memmap.flags & EFI_MEMMAP_LATE);
89 return __efi_memmap_init(data);
92 void __init efi_memmap_unmap(void)
94 if (!efi_enabled(EFI_MEMMAP))
97 if (!(efi.memmap.flags & EFI_MEMMAP_LATE)) {
100 size = efi.memmap.desc_size * efi.memmap.nr_map;
101 early_memunmap(efi.memmap.map, size);
103 memunmap(efi.memmap.map);
106 efi.memmap.map = NULL;
107 clear_bit(EFI_MEMMAP, &efi.flags);
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
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.
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.
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.
131 * Returns: zero on success, a negative error code on failure.
133 int __init efi_memmap_init_late(phys_addr_t addr, unsigned long size)
135 struct efi_memory_map_data data = {
138 .flags = EFI_MEMMAP_LATE,
141 /* Did we forget to unmap the early EFI memmap? */
142 WARN_ON(efi.memmap.map);
144 /* Were we already called? */
145 WARN_ON(efi.memmap.flags & EFI_MEMMAP_LATE);
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.
152 data.desc_version = efi.memmap.desc_version;
153 data.desc_size = efi.memmap.desc_size;
155 return __efi_memmap_init(&data);