1 /******************************************************************************
2 *
3 * Module Name: tbutils - Table manipulation utilities
4 *
5 *****************************************************************************/
6
7 /*
8 * Copyright (C) 2000 - 2005, R. Byron Moore
9 * All rights reserved.
10 *
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
13 * are met:
14 * 1. Redistributions of source code must retain the above copyright
15 * notice, this list of conditions, and the following disclaimer,
16 * without modification.
17 * 2. Redistributions in binary form must reproduce at minimum a disclaimer
18 * substantially similar to the "NO WARRANTY" disclaimer below
19 * ("Disclaimer") and any redistribution must be conditioned upon
20 * including a substantially similar Disclaimer requirement for further
21 * binary redistribution.
22 * 3. Neither the names of the above-listed copyright holders nor the names
23 * of any contributors may be used to endorse or promote products derived
24 * from this software without specific prior written permission.
25 *
26 * Alternatively, this software may be distributed under the terms of the
27 * GNU General Public License ("GPL") version 2 as published by the Free
28 * Software Foundation.
29 *
30 * NO WARRANTY
31 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
32 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
33 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
34 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
35 * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
36 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
37 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
38 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
39 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
40 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
41 * POSSIBILITY OF SUCH DAMAGES.
42 */
43
44
45 #include <acpi/acpi.h>
46 #include <acpi/actables.h>
47
48
49 #define _COMPONENT ACPI_TABLES
50 ACPI_MODULE_NAME ("tbutils")
51
52
53 /*******************************************************************************
54 *
55 * FUNCTION: acpi_tb_handle_to_object
56 *
57 * PARAMETERS: table_id - Id for which the function is searching
58 * table_desc - Pointer to return the matching table
59 * descriptor.
60 *
61 * RETURN: Search the tables to find one with a matching table_id and
62 * return a pointer to that table descriptor.
63 *
64 ******************************************************************************/
65 #ifdef ACPI_FUTURE_USAGE
66 acpi_status
67 acpi_tb_handle_to_object (
68 u16 table_id,
69 struct acpi_table_desc **return_table_desc)
70 {
71 u32 i;
72 struct acpi_table_desc *table_desc;
73
74
75 ACPI_FUNCTION_NAME ("tb_handle_to_object");
76
77
78 for (i = 0; i < ACPI_TABLE_MAX; i++) {
79 table_desc = acpi_gbl_table_lists[i].next;
80 while (table_desc) {
81 if (table_desc->table_id == table_id) {
82 *return_table_desc = table_desc;
83 return (AE_OK);
84 }
85
86 table_desc = table_desc->next;
87 }
88 }
89
90 ACPI_DEBUG_PRINT ((ACPI_DB_ERROR, "table_id=%X does not exist\n", table_id));
91 return (AE_BAD_PARAMETER);
92 }
93 #endif /* ACPI_FUTURE_USAGE */
94
95
96 /*******************************************************************************
97 *
98 * FUNCTION: acpi_tb_validate_table_header
99 *
100 * PARAMETERS: table_header - Logical pointer to the table
101 *
102 * RETURN: Status
103 *
104 * DESCRIPTION: Check an ACPI table header for validity
105 *
106 * NOTE: Table pointers are validated as follows:
107 * 1) Table pointer must point to valid physical memory
108 * 2) Signature must be 4 ASCII chars, even if we don't recognize the
109 * name
110 * 3) Table must be readable for length specified in the header
111 * 4) Table checksum must be valid (with the exception of the FACS
112 * which has no checksum because it contains variable fields)
113 *
114 ******************************************************************************/
115
116 acpi_status
117 acpi_tb_validate_table_header (
118 struct acpi_table_header *table_header)
119 {
120 acpi_name signature;
121
122
123 ACPI_FUNCTION_NAME ("tb_validate_table_header");
124
125
126 /* Verify that this is a valid address */
127
128 if (!acpi_os_readable (table_header, sizeof (struct acpi_table_header))) {
129 ACPI_DEBUG_PRINT ((ACPI_DB_ERROR,
130 "Cannot read table header at %p\n", table_header));
131 return (AE_BAD_ADDRESS);
132 }
133
134 /* Ensure that the signature is 4 ASCII characters */
135
136 ACPI_MOVE_32_TO_32 (&signature, table_header->signature);
137 if (!acpi_ut_valid_acpi_name (signature)) {
138 ACPI_DEBUG_PRINT ((ACPI_DB_ERROR,
139 "Table signature at %p [%p] has invalid characters\n",
140 table_header, &signature));
141
142 ACPI_REPORT_WARNING (("Invalid table signature found: [%4.4s]\n",
143 (char *) &signature));
144 ACPI_DUMP_BUFFER (table_header, sizeof (struct acpi_table_header));
145 return (AE_BAD_SIGNATURE);
146 }
147
148 /* Validate the table length */
149
150 if (table_header->length < sizeof (struct acpi_table_header)) {
151 ACPI_DEBUG_PRINT ((ACPI_DB_ERROR,
152 "Invalid length in table header %p name %4.4s\n",
153 table_header, (char *) &signature));
154
155 ACPI_REPORT_WARNING (("Invalid table header length (0x%X) found\n",
156 (u32) table_header->length));
157 ACPI_DUMP_BUFFER (table_header, sizeof (struct acpi_table_header));
158 return (AE_BAD_HEADER);
159 }
160
161 return (AE_OK);
162 }
163
164
165 /*******************************************************************************
166 *
167 * FUNCTION: acpi_tb_verify_table_checksum
168 *
169 * PARAMETERS: *table_header - ACPI table to verify
170 *
171 * RETURN: 8 bit checksum of table
172 *
173 * DESCRIPTION: Does an 8 bit checksum of table and returns status. A correct
174 * table should have a checksum of 0.
175 *
176 ******************************************************************************/
177
178 acpi_status
179 acpi_tb_verify_table_checksum (
180 struct acpi_table_header *table_header)
181 {
182 u8 checksum;
183 acpi_status status = AE_OK;
184
185
186 ACPI_FUNCTION_TRACE ("tb_verify_table_checksum");
187
188
189 /* Compute the checksum on the table */
190
191 checksum = acpi_tb_checksum (table_header, table_header->length);
192
193 /* Return the appropriate exception */
194
195 if (checksum) {
196 ACPI_REPORT_WARNING (("Invalid checksum in table [%4.4s] (%02X, sum %02X is not zero)\n",
197 table_header->signature, (u32) table_header->checksum, (u32) checksum));
198
199 status = AE_BAD_CHECKSUM;
200 }
201 return_ACPI_STATUS (status);
202 }
203
204
205 /*******************************************************************************
206 *
207 * FUNCTION: acpi_tb_checksum
208 *
209 * PARAMETERS: Buffer - Buffer to checksum
210 * Length - Size of the buffer
211 *
212 * RETURNS 8 bit checksum of buffer
213 *
214 * DESCRIPTION: Computes an 8 bit checksum of the buffer(length) and returns it.
215 *
216 ******************************************************************************/
217
218 u8
219 acpi_tb_checksum (
220 void *buffer,
221 u32 length)
222 {
223 const u8 *limit;
224 const u8 *rover;
225 u8 sum = 0;
226
227
228 if (buffer && length) {
229 /* Buffer and Length are valid */
230
231 limit = (u8 *) buffer + length;
232
233 for (rover = buffer; rover < limit; rover++) {
234 sum = (u8) (sum + *rover);
235 }
236 }
237 return (sum);
238 }
239
240
241
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