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 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 */ efi_free(unsigned long size,unsigned long addr)121 void 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 } 131