1/*
2 * Copyright (C) 2013, 2014 Linaro Ltd;  <roy.franz@linaro.org>
3 *
4 * This file implements the EFI boot stub for the arm64 kernel.
5 * Adapted from ARM version by Mark Salter <msalter@redhat.com>
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
10 *
11 */
12#include <linux/efi.h>
13#include <asm/efi.h>
14#include <asm/sections.h>
15
16efi_status_t __init handle_kernel_image(efi_system_table_t *sys_table_arg,
17					unsigned long *image_addr,
18					unsigned long *image_size,
19					unsigned long *reserve_addr,
20					unsigned long *reserve_size,
21					unsigned long dram_base,
22					efi_loaded_image_t *image)
23{
24	efi_status_t status;
25	unsigned long kernel_size, kernel_memsize = 0;
26	unsigned long nr_pages;
27	void *old_image_addr = (void *)*image_addr;
28	unsigned long preferred_offset;
29
30	/*
31	 * The preferred offset of the kernel Image is TEXT_OFFSET bytes beyond
32	 * a 2 MB aligned base, which itself may be lower than dram_base, as
33	 * long as the resulting offset equals or exceeds it.
34	 */
35	preferred_offset = round_down(dram_base, SZ_2M) + TEXT_OFFSET;
36	if (preferred_offset < dram_base)
37		preferred_offset += SZ_2M;
38
39	/* Relocate the image, if required. */
40	kernel_size = _edata - _text;
41	if (*image_addr != preferred_offset) {
42		kernel_memsize = kernel_size + (_end - _edata);
43
44		/*
45		 * First, try a straight allocation at the preferred offset.
46		 * This will work around the issue where, if dram_base == 0x0,
47		 * efi_low_alloc() refuses to allocate at 0x0 (to prevent the
48		 * address of the allocation to be mistaken for a FAIL return
49		 * value or a NULL pointer). It will also ensure that, on
50		 * platforms where the [dram_base, dram_base + TEXT_OFFSET)
51		 * interval is partially occupied by the firmware (like on APM
52		 * Mustang), we can still place the kernel at the address
53		 * 'dram_base + TEXT_OFFSET'.
54		 */
55		*image_addr = *reserve_addr = preferred_offset;
56		nr_pages = round_up(kernel_memsize, EFI_ALLOC_ALIGN) /
57			   EFI_PAGE_SIZE;
58		status = efi_call_early(allocate_pages, EFI_ALLOCATE_ADDRESS,
59					EFI_LOADER_DATA, nr_pages,
60					(efi_physical_addr_t *)reserve_addr);
61		if (status != EFI_SUCCESS) {
62			kernel_memsize += TEXT_OFFSET;
63			status = efi_low_alloc(sys_table_arg, kernel_memsize,
64					       SZ_2M, reserve_addr);
65
66			if (status != EFI_SUCCESS) {
67				pr_efi_err(sys_table_arg, "Failed to relocate kernel\n");
68				return status;
69			}
70			*image_addr = *reserve_addr + TEXT_OFFSET;
71		}
72		memcpy((void *)*image_addr, old_image_addr, kernel_size);
73		*reserve_size = kernel_memsize;
74	}
75
76
77	return EFI_SUCCESS;
78}
79