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
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
|
/*****************************************************************************\
* cmos_ops.c
*****************************************************************************
* Copyright (C) 2002-2005 The Regents of the University of California.
* Produced at the Lawrence Livermore National Laboratory.
* Written by David S. Peterson <dsp@llnl.gov> <dave_peterson@pobox.com>.
* UCRL-CODE-2003-012
* All rights reserved.
*
* This file is part of nvramtool, a utility for reading/writing coreboot
* parameters and displaying information from the coreboot table.
* For details, see https://coreboot.org/nvramtool.
*
* Please also read the file DISCLAIMER which is included in this software
* distribution.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License (as published by the
* Free Software Foundation) version 2, dated June 1991.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the IMPLIED WARRANTY OF
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the terms and
* conditions of the GNU General Public License for more details.
\*****************************************************************************/
#include "common.h"
#include "cmos_ops.h"
#include "cmos_lowlevel.h"
static int prepare_cmos_op_common(const cmos_entry_t * e);
/****************************************************************************
* prepare_cmos_op_common
*
* Perform a few checks common to both reads and writes.
****************************************************************************/
static int prepare_cmos_op_common(const cmos_entry_t * e)
{
int result;
if (e->config == CMOS_ENTRY_RESERVED)
/* Access to reserved parameters is not permitted. */
return CMOS_OP_RESERVED;
if ((result = verify_cmos_op(e->bit, e->length, e->config)) != OK)
return result;
assert(e->length > 0);
return OK;
}
/****************************************************************************
* prepare_cmos_read
*
* The caller wishes to read a CMOS parameter represented by 'e'. Perform
* sanity checking on 'e'. If a problem was found with e, return an error
* code. Else return OK.
****************************************************************************/
int prepare_cmos_read(const cmos_entry_t * e)
{
int result;
if ((result = prepare_cmos_op_common(e)) != OK)
return result;
switch (e->config) {
case CMOS_ENTRY_ENUM:
case CMOS_ENTRY_HEX:
case CMOS_ENTRY_STRING:
break;
default:
BUG();
}
return OK;
}
/****************************************************************************
* prepare_cmos_write
*
* The caller wishes to set a CMOS parameter represented by 'e' to a value
* whose string representation is stored in 'value_str'. Perform sanity
* checking on 'value_str'. On error, return an error code. Else store the
* numeric equivalent of 'value_str' in '*value' and return OK.
****************************************************************************/
int prepare_cmos_write(const cmos_entry_t * e, const char value_str[],
unsigned long long *value)
{
const cmos_enum_t *q;
unsigned long long out;
const char *p;
char *memory = NULL;
int negative, result, found_one;
if ((result = prepare_cmos_op_common(e)) != OK)
return result;
switch (e->config) {
case CMOS_ENTRY_ENUM:
/* Make sure the user's input corresponds to a valid option. */
for (q = first_cmos_enum_id(e->config_id), found_one = 0;
q != NULL; q = next_cmos_enum_id(q)) {
found_one = 1;
if (!strncmp(q->text, value_str, CMOS_MAX_TEXT_LENGTH))
break;
}
if (!found_one)
return CMOS_OP_NO_MATCHING_ENUM;
if (q == NULL)
return CMOS_OP_BAD_ENUM_VALUE;
out = q->value;
break;
case CMOS_ENTRY_HEX:
/* See if the first character of 'value_str' (excluding
* any initial whitespace) is a minus sign.
*/
for (p = value_str; isspace((int)(unsigned char)*p); p++) ;
negative = (*p == '-');
out = strtoull(value_str, (char **)&p, 0);
if (*p)
return CMOS_OP_INVALID_INT;
/* If we get this far, the user specified a valid integer.
* However we do not currently support the use of negative
* numbers as CMOS parameter values.
*/
if (negative)
return CMOS_OP_NEGATIVE_INT;
break;
case CMOS_ENTRY_STRING:
if (e->length < (8 * strlen(value_str)))
return CMOS_OP_VALUE_TOO_WIDE;
memory = malloc(e->length / 8);
memset(memory, 0, e->length / 8);
strcpy(memory, value_str);
out = (unsigned long)memory;
break;
default:
BUG();
}
if ((e->length < (8 * sizeof(*value))) && (out >= (1ull << e->length))) {
if (memory) free(memory);
return CMOS_OP_VALUE_TOO_WIDE;
}
*value = out;
return OK;
}
/****************************************************************************
* cmos_checksum_read
*
* Read the checksum for the coreboot parameters stored in CMOS and return
* this value.
****************************************************************************/
uint16_t cmos_checksum_read(void)
{
uint16_t lo, hi;
/* The checksum is stored in a big-endian format. */
hi = cmos_read_byte(cmos_checksum_index);
lo = cmos_read_byte(cmos_checksum_index + 1);
return (hi << 8) + lo;
}
/****************************************************************************
* cmos_checksum_write
*
* Set the checksum for the coreboot parameters stored in CMOS to
* 'checksum'.
****************************************************************************/
void cmos_checksum_write(uint16_t checksum)
{
unsigned char lo, hi;
/* The checksum is stored in a big-endian format. */
hi = (unsigned char)(checksum >> 8);
lo = (unsigned char)(checksum & 0x00ff);
cmos_write_byte(cmos_checksum_index, hi);
cmos_write_byte(cmos_checksum_index + 1, lo);
}
/****************************************************************************
* cmos_checksum_compute
*
* Compute a checksum for the coreboot parameter values currently stored in
* CMOS and return this checksum.
****************************************************************************/
uint16_t cmos_checksum_compute(void)
{
unsigned i, sum;
sum = 0;
for (i = cmos_checksum_start; i <= cmos_checksum_end; i++)
sum += cmos_read_byte(i);
return (uint16_t)(sum & 0xffff);
}
/****************************************************************************
* cmos_checksum_verify
*
* Verify that the coreboot CMOS checksum is valid. If checksum is not
* valid then print warning message and exit.
****************************************************************************/
void cmos_checksum_verify(void)
{
uint16_t computed, actual;
set_iopl(3);
computed = cmos_checksum_compute();
actual = cmos_checksum_read();
set_iopl(0);
if (computed != actual) {
fprintf(stderr, "%s: Warning: coreboot CMOS checksum is bad.\n",
prog_name);
fprintf(stderr, "Computed checksum: 0x%x. Stored checksum: 0x%x\n",
computed, actual);
exit(1);
}
}
|
