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_get_memory_map() - get memory map
10 * @map: pointer to memory map pointer to which to assign the
11 * newly allocated memory map
12 * @install_cfg_tbl: whether or not to install the boot memory map as a
13 * configuration table
14 *
15 * Retrieve the UEFI memory map. The allocated memory leaves room for
16 * up to EFI_MMAP_NR_SLACK_SLOTS additional memory map entries.
17 *
18 * Return: status code
19 */
efi_get_memory_map(struct efi_boot_memmap ** map,bool install_cfg_tbl)20 efi_status_t efi_get_memory_map(struct efi_boot_memmap **map,
21 bool install_cfg_tbl)
22 {
23 int memtype = install_cfg_tbl ? EFI_ACPI_RECLAIM_MEMORY
24 : EFI_LOADER_DATA;
25 efi_guid_t tbl_guid = LINUX_EFI_BOOT_MEMMAP_GUID;
26 struct efi_boot_memmap *m, tmp;
27 efi_status_t status;
28 unsigned long size;
29
30 tmp.map_size = 0;
31 status = efi_bs_call(get_memory_map, &tmp.map_size, NULL, &tmp.map_key,
32 &tmp.desc_size, &tmp.desc_ver);
33 if (status != EFI_BUFFER_TOO_SMALL)
34 return EFI_LOAD_ERROR;
35
36 size = tmp.map_size + tmp.desc_size * EFI_MMAP_NR_SLACK_SLOTS;
37 status = efi_bs_call(allocate_pool, memtype, sizeof(*m) + size,
38 (void **)&m);
39 if (status != EFI_SUCCESS)
40 return status;
41
42 if (install_cfg_tbl) {
43 /*
44 * Installing a configuration table might allocate memory, and
45 * this may modify the memory map. This means we should install
46 * the configuration table first, and re-install or delete it
47 * as needed.
48 */
49 status = efi_bs_call(install_configuration_table, &tbl_guid, m);
50 if (status != EFI_SUCCESS)
51 goto free_map;
52 }
53
54 m->buff_size = m->map_size = size;
55 status = efi_bs_call(get_memory_map, &m->map_size, m->map, &m->map_key,
56 &m->desc_size, &m->desc_ver);
57 if (status != EFI_SUCCESS)
58 goto uninstall_table;
59
60 *map = m;
61 return EFI_SUCCESS;
62
63 uninstall_table:
64 if (install_cfg_tbl)
65 efi_bs_call(install_configuration_table, &tbl_guid, NULL);
66 free_map:
67 efi_bs_call(free_pool, m);
68 return status;
69 }
70
71 /**
72 * efi_allocate_pages() - Allocate memory pages
73 * @size: minimum number of bytes to allocate
74 * @addr: On return the address of the first allocated page. The first
75 * allocated page has alignment EFI_ALLOC_ALIGN which is an
76 * architecture dependent multiple of the page size.
77 * @max: the address that the last allocated memory page shall not
78 * exceed
79 *
80 * Allocate pages as EFI_LOADER_DATA. The allocated pages are aligned according
81 * to EFI_ALLOC_ALIGN. The last allocated page will not exceed the address
82 * given by @max.
83 *
84 * Return: status code
85 */
efi_allocate_pages(unsigned long size,unsigned long * addr,unsigned long max)86 efi_status_t efi_allocate_pages(unsigned long size, unsigned long *addr,
87 unsigned long max)
88 {
89 efi_physical_addr_t alloc_addr;
90 efi_status_t status;
91
92 if (EFI_ALLOC_ALIGN > EFI_PAGE_SIZE)
93 return efi_allocate_pages_aligned(size, addr, max,
94 EFI_ALLOC_ALIGN);
95
96 alloc_addr = ALIGN_DOWN(max + 1, EFI_ALLOC_ALIGN) - 1;
97 status = efi_bs_call(allocate_pages, EFI_ALLOCATE_MAX_ADDRESS,
98 EFI_LOADER_DATA, DIV_ROUND_UP(size, EFI_PAGE_SIZE),
99 &alloc_addr);
100 if (status != EFI_SUCCESS)
101 return status;
102
103 *addr = alloc_addr;
104 return EFI_SUCCESS;
105 }
106
107 /**
108 * efi_free() - free memory pages
109 * @size: size of the memory area to free in bytes
110 * @addr: start of the memory area to free (must be EFI_PAGE_SIZE
111 * aligned)
112 *
113 * @size is rounded up to a multiple of EFI_ALLOC_ALIGN which is an
114 * architecture specific multiple of EFI_PAGE_SIZE. So this function should
115 * only be used to return pages allocated with efi_allocate_pages() or
116 * efi_low_alloc_above().
117 */
efi_free(unsigned long size,unsigned long addr)118 void efi_free(unsigned long size, unsigned long addr)
119 {
120 unsigned long nr_pages;
121
122 if (!size)
123 return;
124
125 nr_pages = round_up(size, EFI_ALLOC_ALIGN) / EFI_PAGE_SIZE;
126 efi_bs_call(free_pages, addr, nr_pages);
127 }
128