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Commit e38457c3 authored by Ard Biesheuvel's avatar Ard Biesheuvel Committed by Will Deacon
Browse files

arm64: efi: prefer AllocatePages() over efi_low_alloc() for vmlinux 



When allocating memory for the kernel image, try the AllocatePages()
boot service to obtain memory at the preferred offset of
'dram_base + TEXT_OFFSET', and only revert to efi_low_alloc() if that
fails. This is the only way to allocate at the base of DRAM if DRAM
starts at 0x0, since efi_low_alloc() refuses to allocate at 0x0.

Tested-by: default avatarHaojian Zhuang <haojian.zhuang@linaro.org>
Reviewed-by: default avatarMark Rutland <mark.rutland@arm.com>
Signed-off-by: default avatarArd Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: default avatarWill Deacon <will.deacon@arm.com>
parent e094d445

arch/arm64/kernel/efi-stub.c

+32 −9
Original line number Diff line number Diff line
@@ -13,7 +13,7 @@ 
#include <asm/efi.h>

#include <asm/sections.h>



efi_status_t __init handle_kernel_image(efi_system_table_t *sys_table,

efi_status_t __init handle_kernel_image(efi_system_table_t *sys_table_arg,

					unsigned long *image_addr,

					unsigned long *image_size,

					unsigned long *reserve_addr,
@@ -23,21 +23,44 @@ efi_status_t __init handle_kernel_image(efi_system_table_t *sys_table, 
{

	efi_status_t status;

	unsigned long kernel_size, kernel_memsize = 0;

	unsigned long nr_pages;

	void *old_image_addr = (void *)*image_addr;



	/* Relocate the image, if required. */

	kernel_size = _edata - _text;

	if (*image_addr != (dram_base + TEXT_OFFSET)) {

		kernel_memsize = kernel_size + (_end - _edata);

		status = efi_low_alloc(sys_table, kernel_memsize + TEXT_OFFSET,



		/*

		 * First, try a straight allocation at the preferred offset.

		 * This will work around the issue where, if dram_base == 0x0,

		 * efi_low_alloc() refuses to allocate at 0x0 (to prevent the

		 * address of the allocation to be mistaken for a FAIL return

		 * value or a NULL pointer). It will also ensure that, on

		 * platforms where the [dram_base, dram_base + TEXT_OFFSET)

		 * interval is partially occupied by the firmware (like on APM

		 * Mustang), we can still place the kernel at the address

		 * 'dram_base + TEXT_OFFSET'.

		 */

		*image_addr = *reserve_addr = dram_base + TEXT_OFFSET;

		nr_pages = round_up(kernel_memsize, EFI_ALLOC_ALIGN) /

			   EFI_PAGE_SIZE;

		status = efi_call_early(allocate_pages, EFI_ALLOCATE_ADDRESS,

					EFI_LOADER_DATA, nr_pages,

					(efi_physical_addr_t *)reserve_addr);

		if (status != EFI_SUCCESS) {

			kernel_memsize += TEXT_OFFSET;

			status = efi_low_alloc(sys_table_arg, kernel_memsize,

					       SZ_2M, reserve_addr);



			if (status != EFI_SUCCESS) {

			pr_efi_err(sys_table, "Failed to relocate kernel\n");

				pr_efi_err(sys_table_arg, "Failed to relocate kernel\n");

				return status;

			}

		memcpy((void *)*reserve_addr + TEXT_OFFSET, (void *)*image_addr,

		       kernel_size);

			*image_addr = *reserve_addr + TEXT_OFFSET;

		*reserve_size = kernel_memsize + TEXT_OFFSET;

		}

		memcpy((void *)*image_addr, old_image_addr, kernel_size);

		*reserve_size = kernel_memsize;

	}