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
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
|
// SPDX-License-Identifier: GPL-2.0-only
/*
* SMI methods for use with dell-smbios
*
* Copyright (c) Red Hat <mjg@redhat.com>
* Copyright (c) 2014 Gabriele Mazzotta <gabriele.mzt@gmail.com>
* Copyright (c) 2014 Pali Rohár <pali.rohar@gmail.com>
* Copyright (c) 2017 Dell Inc.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/dmi.h>
#include <linux/gfp.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/platform_device.h>
#include "dcdbas.h"
#include "dell-smbios.h"
static int da_command_address;
static int da_command_code;
static struct calling_interface_buffer *buffer;
static struct platform_device *platform_device;
static DEFINE_MUTEX(smm_mutex);
static const struct dmi_system_id dell_device_table[] __initconst = {
{
.ident = "Dell laptop",
.matches = {
DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
DMI_MATCH(DMI_CHASSIS_TYPE, "8"),
},
},
{
.matches = {
DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
DMI_MATCH(DMI_CHASSIS_TYPE, "9"), /*Laptop*/
},
},
{
.matches = {
DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
DMI_MATCH(DMI_CHASSIS_TYPE, "10"), /*Notebook*/
},
},
{
.ident = "Dell Computer Corporation",
.matches = {
DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
DMI_MATCH(DMI_CHASSIS_TYPE, "8"),
},
},
{ }
};
MODULE_DEVICE_TABLE(dmi, dell_device_table);
static void parse_da_table(const struct dmi_header *dm)
{
struct calling_interface_structure *table =
container_of(dm, struct calling_interface_structure, header);
/* 4 bytes of table header, plus 7 bytes of Dell header, plus at least
* 6 bytes of entry
*/
if (dm->length < 17)
return;
da_command_address = table->cmdIOAddress;
da_command_code = table->cmdIOCode;
}
static void find_cmd_address(const struct dmi_header *dm, void *dummy)
{
switch (dm->type) {
case 0xda: /* Calling interface */
parse_da_table(dm);
break;
}
}
static int dell_smbios_smm_call(struct calling_interface_buffer *input)
{
struct smi_cmd command;
size_t size;
size = sizeof(struct calling_interface_buffer);
command.magic = SMI_CMD_MAGIC;
command.command_address = da_command_address;
command.command_code = da_command_code;
command.ebx = virt_to_phys(buffer);
command.ecx = 0x42534931;
mutex_lock(&smm_mutex);
memcpy(buffer, input, size);
dcdbas_smi_request(&command);
memcpy(input, buffer, size);
mutex_unlock(&smm_mutex);
return 0;
}
/* When enabled this indicates that SMM won't work */
static bool test_wsmt_enabled(void)
{
struct calling_interface_token *wsmt;
/* if token doesn't exist, SMM will work */
wsmt = dell_smbios_find_token(WSMT_EN_TOKEN);
if (!wsmt)
return false;
/* If token exists, try to access over SMM but set a dummy return.
* - If WSMT disabled it will be overwritten by SMM
* - If WSMT enabled then dummy value will remain
*/
buffer->cmd_class = CLASS_TOKEN_READ;
buffer->cmd_select = SELECT_TOKEN_STD;
memset(buffer, 0, sizeof(struct calling_interface_buffer));
buffer->input[0] = wsmt->location;
buffer->output[0] = 99;
dell_smbios_smm_call(buffer);
if (buffer->output[0] == 99)
return true;
return false;
}
int init_dell_smbios_smm(void)
{
int ret;
/*
* Allocate buffer below 4GB for SMI data--only 32-bit physical addr
* is passed to SMI handler.
*/
buffer = (void *)__get_free_page(GFP_KERNEL | GFP_DMA32);
if (!buffer)
return -ENOMEM;
dmi_walk(find_cmd_address, NULL);
if (test_wsmt_enabled()) {
pr_debug("Disabling due to WSMT enabled\n");
ret = -ENODEV;
goto fail_wsmt;
}
platform_device = platform_device_alloc("dell-smbios", 1);
if (!platform_device) {
ret = -ENOMEM;
goto fail_platform_device_alloc;
}
ret = platform_device_add(platform_device);
if (ret)
goto fail_platform_device_add;
ret = dell_smbios_register_device(&platform_device->dev,
&dell_smbios_smm_call);
if (ret)
goto fail_register;
return 0;
fail_register:
platform_device_del(platform_device);
fail_platform_device_add:
platform_device_put(platform_device);
fail_wsmt:
fail_platform_device_alloc:
free_page((unsigned long)buffer);
return ret;
}
void exit_dell_smbios_smm(void)
{
if (platform_device) {
dell_smbios_unregister_device(&platform_device->dev);
platform_device_unregister(platform_device);
free_page((unsigned long)buffer);
}
}
|
