drivers/firmware/efi/libstub/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  */
  20 efi_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  */
  82 efi_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  */
 117 void 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 }