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  */
24 efi_status_t efi_allocate_pages_aligned(unsigned long size, unsigned long *addr,
25 					unsigned long max, unsigned long align,
26 					int memory_type)
27 {
28 	efi_physical_addr_t alloc_addr;
29 	efi_status_t status;
30 	int slack;
31 
32 	if (align < EFI_ALLOC_ALIGN)
33 		align = EFI_ALLOC_ALIGN;
34 
35 	alloc_addr = ALIGN_DOWN(max + 1, align) - 1;
36 	size = round_up(size, EFI_ALLOC_ALIGN);
37 	slack = align / EFI_PAGE_SIZE - 1;
38 
39 	status = efi_bs_call(allocate_pages, EFI_ALLOCATE_MAX_ADDRESS,
40 			     memory_type, size / EFI_PAGE_SIZE + slack,
41 			     &alloc_addr);
42 	if (status != EFI_SUCCESS)
43 		return status;
44 
45 	*addr = ALIGN((unsigned long)alloc_addr, align);
46 
47 	if (slack > 0) {
48 		int l = (alloc_addr & (align - 1)) / EFI_PAGE_SIZE;
49 
50 		if (l) {
51 			efi_bs_call(free_pages, alloc_addr, slack - l + 1);
52 			slack = l - 1;
53 		}
54 		if (slack)
55 			efi_bs_call(free_pages, *addr + size, slack);
56 	}
57 	return EFI_SUCCESS;
58 }
59