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
|
/* SPDX-License-Identifier: LGPL-2.1-or-later */
#include "initrd.h"
#include "proto/device-path.h"
#include "proto/load-file.h"
#include "util.h"
#define LINUX_INITRD_MEDIA_GUID \
GUID_DEF(0x5568e427, 0x68fc, 0x4f3d, 0xac, 0x74, 0xca, 0x55, 0x52, 0x31, 0xcc, 0x68)
/* extend LoadFileProtocol */
struct initrd_loader {
EFI_LOAD_FILE_PROTOCOL load_file;
const void *address;
size_t length;
};
/* static structure for LINUX_INITRD_MEDIA device path
see https://github.com/torvalds/linux/blob/v5.13/drivers/firmware/efi/libstub/efi-stub-helper.c
*/
static const struct {
VENDOR_DEVICE_PATH vendor;
EFI_DEVICE_PATH end;
} _packed_ efi_initrd_device_path = {
.vendor = {
.Header = {
.Type = MEDIA_DEVICE_PATH,
.SubType = MEDIA_VENDOR_DP,
.Length = sizeof(efi_initrd_device_path.vendor),
},
.Guid = LINUX_INITRD_MEDIA_GUID
},
.end = {
.Type = END_DEVICE_PATH_TYPE,
.SubType = END_ENTIRE_DEVICE_PATH_SUBTYPE,
.Length = sizeof(efi_initrd_device_path.end),
}
};
static EFIAPI EFI_STATUS initrd_load_file(
EFI_LOAD_FILE_PROTOCOL *this,
EFI_DEVICE_PATH *file_path,
bool boot_policy,
size_t *buffer_size,
void *buffer) {
struct initrd_loader *loader;
if (!this || !buffer_size || !file_path)
return EFI_INVALID_PARAMETER;
if (boot_policy)
return EFI_UNSUPPORTED;
loader = (struct initrd_loader *) this;
if (loader->length == 0 || !loader->address)
return EFI_NOT_FOUND;
if (!buffer || *buffer_size < loader->length) {
*buffer_size = loader->length;
return EFI_BUFFER_TOO_SMALL;
}
memcpy(buffer, loader->address, loader->length);
*buffer_size = loader->length;
return EFI_SUCCESS;
}
EFI_STATUS initrd_register(
const void *initrd_address,
size_t initrd_length,
EFI_HANDLE *ret_initrd_handle) {
EFI_STATUS err;
EFI_DEVICE_PATH *dp = (EFI_DEVICE_PATH *) &efi_initrd_device_path;
EFI_HANDLE handle;
struct initrd_loader *loader;
assert(ret_initrd_handle);
if (!initrd_address || initrd_length == 0)
return EFI_SUCCESS;
/* check if a LINUX_INITRD_MEDIA_GUID DevicePath is already registered.
LocateDevicePath checks for the "closest DevicePath" and returns its handle,
where as InstallMultipleProtocolInterfaces only matches identical DevicePaths.
*/
err = BS->LocateDevicePath(MAKE_GUID_PTR(EFI_LOAD_FILE2_PROTOCOL), &dp, &handle);
if (err != EFI_NOT_FOUND) /* InitrdMedia is already registered */
return EFI_ALREADY_STARTED;
loader = xnew(struct initrd_loader, 1);
*loader = (struct initrd_loader) {
.load_file.LoadFile = initrd_load_file,
.address = initrd_address,
.length = initrd_length
};
/* create a new handle and register the LoadFile2 protocol with the InitrdMediaPath on it */
err = BS->InstallMultipleProtocolInterfaces(
ret_initrd_handle, MAKE_GUID_PTR(EFI_DEVICE_PATH_PROTOCOL),
&efi_initrd_device_path, MAKE_GUID_PTR(EFI_LOAD_FILE2_PROTOCOL),
loader,
NULL);
if (err != EFI_SUCCESS)
free(loader);
return err;
}
EFI_STATUS initrd_unregister(EFI_HANDLE initrd_handle) {
EFI_STATUS err;
struct initrd_loader *loader;
if (!initrd_handle)
return EFI_SUCCESS;
/* get the LoadFile2 protocol that we allocated earlier */
err = BS->HandleProtocol(initrd_handle, MAKE_GUID_PTR(EFI_LOAD_FILE2_PROTOCOL), (void **) &loader);
if (err != EFI_SUCCESS)
return err;
/* uninstall all protocols thus destroying the handle */
err = BS->UninstallMultipleProtocolInterfaces(
initrd_handle, MAKE_GUID_PTR(EFI_DEVICE_PATH_PROTOCOL),
&efi_initrd_device_path, MAKE_GUID_PTR(EFI_LOAD_FILE2_PROTOCOL),
loader,
NULL);
if (err != EFI_SUCCESS)
return err;
initrd_handle = NULL;
free(loader);
return EFI_SUCCESS;
}
|
