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Diffstat (limited to '')
| -rw-r--r-- | drivers/firmware/efi/libstub/alignedmem.c | 57 |
1 files changed, 57 insertions, 0 deletions
diff --git a/drivers/firmware/efi/libstub/alignedmem.c b/drivers/firmware/efi/libstub/alignedmem.c new file mode 100644 index 000000000..1de9878dd --- /dev/null +++ b/drivers/firmware/efi/libstub/alignedmem.c @@ -0,0 +1,57 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include <linux/efi.h> +#include <asm/efi.h> + +#include "efistub.h" + +/** + * efi_allocate_pages_aligned() - Allocate memory pages + * @size: minimum number of bytes to allocate + * @addr: On return the address of the first allocated page. The first + * allocated page has alignment EFI_ALLOC_ALIGN which is an + * architecture dependent multiple of the page size. + * @max: the address that the last allocated memory page shall not + * exceed + * @align: minimum alignment of the base of the allocation + * + * Allocate pages as EFI_LOADER_DATA. The allocated pages are aligned according + * to @align, which should be >= EFI_ALLOC_ALIGN. The last allocated page will + * not exceed the address given by @max. + * + * Return: status code + */ +efi_status_t efi_allocate_pages_aligned(unsigned long size, unsigned long *addr, + unsigned long max, unsigned long align) +{ + efi_physical_addr_t alloc_addr; + efi_status_t status; + int slack; + + if (align < EFI_ALLOC_ALIGN) + align = EFI_ALLOC_ALIGN; + + alloc_addr = ALIGN_DOWN(max + 1, align) - 1; + size = round_up(size, EFI_ALLOC_ALIGN); + slack = align / EFI_PAGE_SIZE - 1; + + status = efi_bs_call(allocate_pages, EFI_ALLOCATE_MAX_ADDRESS, + EFI_LOADER_DATA, size / EFI_PAGE_SIZE + slack, + &alloc_addr); + if (status != EFI_SUCCESS) + return status; + + *addr = ALIGN((unsigned long)alloc_addr, align); + + if (slack > 0) { + int l = (alloc_addr & (align - 1)) / EFI_PAGE_SIZE; + + if (l) { + efi_bs_call(free_pages, alloc_addr, slack - l + 1); + slack = l - 1; + } + if (slack) + efi_bs_call(free_pages, *addr + size, slack); + } + return EFI_SUCCESS; +} |