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	max = min(max, EFI_ALLOC_LIMIT);
 93
 94	if (EFI_ALLOC_ALIGN > EFI_PAGE_SIZE)
 95		return efi_allocate_pages_aligned(size, addr, max,
 96						  EFI_ALLOC_ALIGN,
 97						  EFI_LOADER_DATA);
 98
 99	alloc_addr = ALIGN_DOWN(max + 1, EFI_ALLOC_ALIGN) - 1;
100	status = efi_bs_call(allocate_pages, EFI_ALLOCATE_MAX_ADDRESS,
101			     EFI_LOADER_DATA, DIV_ROUND_UP(size, EFI_PAGE_SIZE),
102			     &alloc_addr);
103	if (status != EFI_SUCCESS)
104		return status;
105
106	*addr = alloc_addr;
107	return EFI_SUCCESS;
108}
109
110/**
111 * efi_free() - free memory pages
112 * @size:	size of the memory area to free in bytes
113 * @addr:	start of the memory area to free (must be EFI_PAGE_SIZE
114 *		aligned)
115 *
116 * @size is rounded up to a multiple of EFI_ALLOC_ALIGN which is an
117 * architecture specific multiple of EFI_PAGE_SIZE. So this function should
118 * only be used to return pages allocated with efi_allocate_pages() or
119 * efi_low_alloc_above().
120 */
121void efi_free(unsigned long size, unsigned long addr)
122{
123	unsigned long nr_pages;
124
125	if (!size)
126		return;
127
128	nr_pages = round_up(size, EFI_ALLOC_ALIGN) / EFI_PAGE_SIZE;
129	efi_bs_call(free_pages, addr, nr_pages);
130}