| Ard Biesheuvel | 43b1df0 | 2020-03-27 16:09:40 +0100 | [diff] [blame] | 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 | { |
| 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) { |
| Atish Patra | 950accba | 2020-06-25 16:45:06 -0700 | [diff] [blame] | 47 | int l = (alloc_addr & (align - 1)) / EFI_PAGE_SIZE; |
| Ard Biesheuvel | 43b1df0 | 2020-03-27 16:09:40 +0100 | [diff] [blame] | 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 | } |