1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
|
// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2013, 2014 Linaro Ltd; <roy.franz@linaro.org>
*
* This file implements the EFI boot stub for the arm64 kernel.
* Adapted from ARM version by Mark Salter <msalter@redhat.com>
*/
#include <linux/efi.h>
#include <asm/efi.h>
#include <asm/memory.h>
#include <asm/sections.h>
#include "efistub.h"
/*
* Distro versions of GRUB may ignore the BSS allocation entirely (i.e., fail
* to provide space, and fail to zero it). Check for this condition by double
* checking that the first and the last byte of the image are covered by the
* same EFI memory map entry.
*/
static bool check_image_region(u64 base, u64 size)
{
struct efi_boot_memmap *map;
efi_status_t status;
bool ret = false;
int map_offset;
status = efi_get_memory_map(&map, false);
if (status != EFI_SUCCESS)
return false;
for (map_offset = 0; map_offset < map->map_size; map_offset += map->desc_size) {
efi_memory_desc_t *md = (void *)map->map + map_offset;
u64 end = md->phys_addr + md->num_pages * EFI_PAGE_SIZE;
/*
* Find the region that covers base, and return whether
* it covers base+size bytes.
*/
if (base >= md->phys_addr && base < end) {
ret = (base + size) <= end;
break;
}
}
efi_bs_call(free_pool, map);
return ret;
}
efi_status_t handle_kernel_image(unsigned long *image_addr,
unsigned long *image_size,
unsigned long *reserve_addr,
unsigned long *reserve_size,
efi_loaded_image_t *image,
efi_handle_t image_handle)
{
efi_status_t status;
unsigned long kernel_size, kernel_codesize, kernel_memsize;
u32 phys_seed = 0;
u64 min_kimg_align = efi_get_kimg_min_align();
if (IS_ENABLED(CONFIG_RANDOMIZE_BASE)) {
efi_guid_t li_fixed_proto = LINUX_EFI_LOADED_IMAGE_FIXED_GUID;
void *p;
if (efi_nokaslr) {
efi_info("KASLR disabled on kernel command line\n");
} else if (efi_bs_call(handle_protocol, image_handle,
&li_fixed_proto, &p) == EFI_SUCCESS) {
efi_info("Image placement fixed by loader\n");
} else {
status = efi_get_random_bytes(sizeof(phys_seed),
(u8 *)&phys_seed);
if (status == EFI_NOT_FOUND) {
efi_info("EFI_RNG_PROTOCOL unavailable\n");
efi_nokaslr = true;
} else if (status != EFI_SUCCESS) {
efi_err("efi_get_random_bytes() failed (0x%lx)\n",
status);
efi_nokaslr = true;
}
}
}
if (image->image_base != _text) {
efi_err("FIRMWARE BUG: efi_loaded_image_t::image_base has bogus value\n");
image->image_base = _text;
}
if (!IS_ALIGNED((u64)_text, SEGMENT_ALIGN))
efi_err("FIRMWARE BUG: kernel image not aligned on %dk boundary\n",
SEGMENT_ALIGN >> 10);
kernel_size = _edata - _text;
kernel_codesize = __inittext_end - _text;
kernel_memsize = kernel_size + (_end - _edata);
*reserve_size = kernel_memsize;
if (IS_ENABLED(CONFIG_RANDOMIZE_BASE) && phys_seed != 0) {
/*
* If KASLR is enabled, and we have some randomness available,
* locate the kernel at a randomized offset in physical memory.
*/
status = efi_random_alloc(*reserve_size, min_kimg_align,
reserve_addr, phys_seed,
EFI_LOADER_CODE, EFI_ALLOC_LIMIT);
if (status != EFI_SUCCESS)
efi_warn("efi_random_alloc() failed: 0x%lx\n", status);
} else {
status = EFI_OUT_OF_RESOURCES;
}
if (status != EFI_SUCCESS) {
if (!check_image_region((u64)_text, kernel_memsize)) {
efi_err("FIRMWARE BUG: Image BSS overlaps adjacent EFI memory region\n");
} else if (IS_ALIGNED((u64)_text, min_kimg_align) &&
(u64)_end < EFI_ALLOC_LIMIT) {
/*
* Just execute from wherever we were loaded by the
* UEFI PE/COFF loader if the placement is suitable.
*/
*image_addr = (u64)_text;
*reserve_size = 0;
return EFI_SUCCESS;
}
status = efi_allocate_pages_aligned(*reserve_size, reserve_addr,
ULONG_MAX, min_kimg_align,
EFI_LOADER_CODE);
if (status != EFI_SUCCESS) {
efi_err("Failed to relocate kernel\n");
*reserve_size = 0;
return status;
}
}
*image_addr = *reserve_addr;
memcpy((void *)*image_addr, _text, kernel_size);
caches_clean_inval_pou(*image_addr, *image_addr + kernel_codesize);
efi_remap_image(*image_addr, *reserve_size, kernel_codesize);
return EFI_SUCCESS;
}
asmlinkage void primary_entry(void);
unsigned long primary_entry_offset(void)
{
/*
* When built as part of the kernel, the EFI stub cannot branch to the
* kernel proper via the image header, as the PE/COFF header is
* strictly not part of the in-memory presentation of the image, only
* of the file representation. So instead, we need to jump to the
* actual entrypoint in the .text region of the image.
*/
return (char *)primary_entry - _text;
}
|
