mem.c

  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	struct efi_boot_memmap tmp, *m __free(efi_pool) = NULL;
 24	int memtype = install_cfg_tbl ? EFI_ACPI_RECLAIM_MEMORY
 25				      : EFI_LOADER_DATA;
 26	efi_guid_t tbl_guid = LINUX_EFI_BOOT_MEMMAP_GUID;
 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			return status;
 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		if (install_cfg_tbl)
 59			efi_bs_call(install_configuration_table, &tbl_guid, NULL);
 60		return status;
 61	}
 62
 63	*map = no_free_ptr(m);
 64	return EFI_SUCCESS;
 65}
 66
 67/**
 68 * efi_allocate_pages() - Allocate memory pages
 69 * @size:	minimum number of bytes to allocate
 70 * @addr:	On return the address of the first allocated page. The first
 71 *		allocated page has alignment EFI_ALLOC_ALIGN which is an
 72 *		architecture dependent multiple of the page size.
 73 * @max:	the address that the last allocated memory page shall not
 74 *		exceed
 75 *
 76 * Allocate pages as EFI_LOADER_DATA. The allocated pages are aligned according
 77 * to EFI_ALLOC_ALIGN. The last allocated page will not exceed the address
 78 * given by @max.
 79 *
 80 * Return:	status code
 81 */
 82efi_status_t efi_allocate_pages(unsigned long size, unsigned long *addr,
 83				unsigned long max)
 84{
 85	efi_physical_addr_t alloc_addr;
 86	efi_status_t status;
 87
 88	max = min(max, EFI_ALLOC_LIMIT);
 89
 90	if (EFI_ALLOC_ALIGN > EFI_PAGE_SIZE)
 91		return efi_allocate_pages_aligned(size, addr, max,
 92						  EFI_ALLOC_ALIGN,
 93						  EFI_LOADER_DATA);
 94
 95	alloc_addr = ALIGN_DOWN(max + 1, EFI_ALLOC_ALIGN) - 1;
 96	status = efi_bs_call(allocate_pages, EFI_ALLOCATE_MAX_ADDRESS,
 97			     EFI_LOADER_DATA, DIV_ROUND_UP(size, EFI_PAGE_SIZE),
 98			     &alloc_addr);
 99	if (status != EFI_SUCCESS)
100		return status;
101
102	*addr = alloc_addr;
103	return EFI_SUCCESS;
104}
105
106/**
107 * efi_free() - free memory pages
108 * @size:	size of the memory area to free in bytes
109 * @addr:	start of the memory area to free (must be EFI_PAGE_SIZE
110 *		aligned)
111 *
112 * @size is rounded up to a multiple of EFI_ALLOC_ALIGN which is an
113 * architecture specific multiple of EFI_PAGE_SIZE. So this function should
114 * only be used to return pages allocated with efi_allocate_pages() or
115 * efi_low_alloc_above().
116 */
117void efi_free(unsigned long size, unsigned long addr)
118{
119	unsigned long nr_pages;
120
121	if (!size)
122		return;
123
124	nr_pages = round_up(size, EFI_ALLOC_ALIGN) / EFI_PAGE_SIZE;
125	efi_bs_call(free_pages, addr, nr_pages);
126}