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 */
20efi_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
63uninstall_table:
64	if (install_cfg_tbl)
65		efi_bs_call(install_configuration_table, &tbl_guid, NULL);
66free_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 */
86efi_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 */
118void 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