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_allocate_pages_aligned() - Allocate memory pages
10 * @size: minimum number of bytes to allocate
11 * @addr: On return the address of the first allocated page. The first
12 * allocated page has alignment EFI_ALLOC_ALIGN which is an
13 * architecture dependent multiple of the page size.
14 * @max: the address that the last allocated memory page shall not
15 * exceed
16 * @align: minimum alignment of the base of the allocation
17 *
18 * Allocate pages as EFI_LOADER_DATA. The allocated pages are aligned according
19 * to @align, which should be >= EFI_ALLOC_ALIGN. The last allocated page will
20 * not exceed the address given by @max.
21 *
22 * Return: status code
23 */
efi_allocate_pages_aligned(unsigned long size,unsigned long * addr,unsigned long max,unsigned long align)24 efi_status_t efi_allocate_pages_aligned(unsigned long size, unsigned long *addr,
25 unsigned long max, unsigned long align)
26 {
27 efi_physical_addr_t alloc_addr;
28 efi_status_t status;
29 int slack;
30
31 if (align < EFI_ALLOC_ALIGN)
32 align = EFI_ALLOC_ALIGN;
33
34 alloc_addr = ALIGN_DOWN(max + 1, align) - 1;
35 size = round_up(size, EFI_ALLOC_ALIGN);
36 slack = align / EFI_PAGE_SIZE - 1;
37
38 status = efi_bs_call(allocate_pages, EFI_ALLOCATE_MAX_ADDRESS,
39 EFI_LOADER_DATA, size / EFI_PAGE_SIZE + slack,
40 &alloc_addr);
41 if (status != EFI_SUCCESS)
42 return status;
43
44 *addr = ALIGN((unsigned long)alloc_addr, align);
45
46 if (slack > 0) {
47 int l = (alloc_addr & (align - 1)) / EFI_PAGE_SIZE;
48
49 if (l) {
50 efi_bs_call(free_pages, alloc_addr, slack - l + 1);
51 slack = l - 1;
52 }
53 if (slack)
54 efi_bs_call(free_pages, *addr + size, slack);
55 }
56 return EFI_SUCCESS;
57 }
58