1 // SPDX-License-Identifier: GPL-2.0
2
3 #include <linux/efi.h>
4 #include <asm/efi.h>
5
6 #include "efistub.h"
7
8 /**
9 * efi_low_alloc_above() - allocate pages at or above given address
10 * @size: size of the memory area to allocate
11 * @align: minimum alignment of the allocated memory area. It should
12 * a power of two.
13 * @addr: on exit the address of the allocated memory
14 * @min: minimum address to used for the memory allocation
15 *
16 * Allocate at the lowest possible address that is not below @min as
17 * EFI_LOADER_DATA. The allocated pages are aligned according to @align but at
18 * least EFI_ALLOC_ALIGN. The first allocated page will not below the address
19 * given by @min.
20 *
21 * Return: status code
22 */
efi_low_alloc_above(unsigned long size,unsigned long align,unsigned long * addr,unsigned long min)23 efi_status_t efi_low_alloc_above(unsigned long size, unsigned long align,
24 unsigned long *addr, unsigned long min)
25 {
26 struct efi_boot_memmap *map;
27 efi_status_t status;
28 unsigned long nr_pages;
29 int i;
30
31 status = efi_get_memory_map(&map, false);
32 if (status != EFI_SUCCESS)
33 goto fail;
34
35 /*
36 * Enforce minimum alignment that EFI or Linux requires when
37 * requesting a specific address. We are doing page-based (or
38 * larger) allocations, and both the address and size must meet
39 * alignment constraints.
40 */
41 if (align < EFI_ALLOC_ALIGN)
42 align = EFI_ALLOC_ALIGN;
43
44 size = round_up(size, EFI_ALLOC_ALIGN);
45 nr_pages = size / EFI_PAGE_SIZE;
46 for (i = 0; i < map->map_size / map->desc_size; i++) {
47 efi_memory_desc_t *desc;
48 unsigned long m = (unsigned long)map->map;
49 u64 start, end;
50
51 desc = efi_early_memdesc_ptr(m, map->desc_size, i);
52
53 if (desc->type != EFI_CONVENTIONAL_MEMORY)
54 continue;
55
56 if (efi_soft_reserve_enabled() &&
57 (desc->attribute & EFI_MEMORY_SP))
58 continue;
59
60 if (desc->num_pages < nr_pages)
61 continue;
62
63 start = desc->phys_addr;
64 end = start + desc->num_pages * EFI_PAGE_SIZE;
65
66 if (start < min)
67 start = min;
68
69 start = round_up(start, align);
70 if ((start + size) > end)
71 continue;
72
73 status = efi_bs_call(allocate_pages, EFI_ALLOCATE_ADDRESS,
74 EFI_LOADER_DATA, nr_pages, &start);
75 if (status == EFI_SUCCESS) {
76 *addr = start;
77 break;
78 }
79 }
80
81 if (i == map->map_size / map->desc_size)
82 status = EFI_NOT_FOUND;
83
84 efi_bs_call(free_pool, map);
85 fail:
86 return status;
87 }
88
89 /**
90 * efi_relocate_kernel() - copy memory area
91 * @image_addr: pointer to address of memory area to copy
92 * @image_size: size of memory area to copy
93 * @alloc_size: minimum size of memory to allocate, must be greater or
94 * equal to image_size
95 * @preferred_addr: preferred target address
96 * @alignment: minimum alignment of the allocated memory area. It
97 * should be a power of two.
98 * @min_addr: minimum target address
99 *
100 * Copy a memory area to a newly allocated memory area aligned according
101 * to @alignment but at least EFI_ALLOC_ALIGN. If the preferred address
102 * is not available, the allocated address will not be below @min_addr.
103 * On exit, @image_addr is updated to the target copy address that was used.
104 *
105 * This function is used to copy the Linux kernel verbatim. It does not apply
106 * any relocation changes.
107 *
108 * Return: status code
109 */
efi_relocate_kernel(unsigned long * image_addr,unsigned long image_size,unsigned long alloc_size,unsigned long preferred_addr,unsigned long alignment,unsigned long min_addr)110 efi_status_t efi_relocate_kernel(unsigned long *image_addr,
111 unsigned long image_size,
112 unsigned long alloc_size,
113 unsigned long preferred_addr,
114 unsigned long alignment,
115 unsigned long min_addr)
116 {
117 unsigned long cur_image_addr;
118 unsigned long new_addr = 0;
119 efi_status_t status;
120 unsigned long nr_pages;
121 efi_physical_addr_t efi_addr = preferred_addr;
122
123 if (!image_addr || !image_size || !alloc_size)
124 return EFI_INVALID_PARAMETER;
125 if (alloc_size < image_size)
126 return EFI_INVALID_PARAMETER;
127
128 cur_image_addr = *image_addr;
129
130 /*
131 * The EFI firmware loader could have placed the kernel image
132 * anywhere in memory, but the kernel has restrictions on the
133 * max physical address it can run at. Some architectures
134 * also have a preferred address, so first try to relocate
135 * to the preferred address. If that fails, allocate as low
136 * as possible while respecting the required alignment.
137 */
138 nr_pages = round_up(alloc_size, EFI_ALLOC_ALIGN) / EFI_PAGE_SIZE;
139 status = efi_bs_call(allocate_pages, EFI_ALLOCATE_ADDRESS,
140 EFI_LOADER_DATA, nr_pages, &efi_addr);
141 new_addr = efi_addr;
142 /*
143 * If preferred address allocation failed allocate as low as
144 * possible.
145 */
146 if (status != EFI_SUCCESS) {
147 status = efi_low_alloc_above(alloc_size, alignment, &new_addr,
148 min_addr);
149 }
150 if (status != EFI_SUCCESS) {
151 efi_err("Failed to allocate usable memory for kernel.\n");
152 return status;
153 }
154
155 /*
156 * We know source/dest won't overlap since both memory ranges
157 * have been allocated by UEFI, so we can safely use memcpy.
158 */
159 memcpy((void *)new_addr, (void *)cur_image_addr, image_size);
160
161 /* Return the new address of the relocated image. */
162 *image_addr = new_addr;
163
164 return status;
165 }
166