aboutsummaryrefslogtreecommitdiff
path: root/drivers/acpi/tables/tbutils.c
blob: 5f14403765140a4affad0235162eacbc337c6be5 (plain)
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
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
/******************************************************************************
 *
 * Module Name: tbutils - Table manipulation utilities
 *
 *****************************************************************************/

/*
 * Copyright (C) 2000 - 2006, R. Byron Moore
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions, and the following disclaimer,
 *    without modification.
 * 2. Redistributions in binary form must reproduce at minimum a disclaimer
 *    substantially similar to the "NO WARRANTY" disclaimer below
 *    ("Disclaimer") and any redistribution must be conditioned upon
 *    including a substantially similar Disclaimer requirement for further
 *    binary redistribution.
 * 3. Neither the names of the above-listed copyright holders nor the names
 *    of any contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 *
 * Alternatively, this software may be distributed under the terms of the
 * GNU General Public License ("GPL") version 2 as published by the Free
 * Software Foundation.
 *
 * NO WARRANTY
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGES.
 */

#include <acpi/acpi.h>
#include <acpi/actables.h>

#define _COMPONENT          ACPI_TABLES
ACPI_MODULE_NAME("tbutils")

/* Local prototypes */
#ifdef ACPI_OBSOLETE_FUNCTIONS
acpi_status
acpi_tb_handle_to_object(u16 table_id, struct acpi_table_desc **table_desc);
#endif

/*******************************************************************************
 *
 * FUNCTION:    acpi_tb_is_table_installed
 *
 * PARAMETERS:  new_table_desc      - Descriptor for new table being installed
 *
 * RETURN:      Status - AE_ALREADY_EXISTS if the table is already installed
 *
 * DESCRIPTION: Determine if an ACPI table is already installed
 *
 * MUTEX:       Table data structures should be locked
 *
 ******************************************************************************/

acpi_status acpi_tb_is_table_installed(struct acpi_table_desc *new_table_desc)
{
	struct acpi_table_desc *table_desc;

	ACPI_FUNCTION_TRACE(tb_is_table_installed);

	/* Get the list descriptor and first table descriptor */

	table_desc = acpi_gbl_table_lists[new_table_desc->type].next;

	/* Examine all installed tables of this type */

	while (table_desc) {
		/*
		 * If the table lengths match, perform a full bytewise compare. This
		 * means that we will allow tables with duplicate oem_table_id(s), as
		 * long as the tables are different in some way.
		 *
		 * Checking if the table has been loaded into the namespace means that
		 * we don't check for duplicate tables during the initial installation
		 * of tables within the RSDT/XSDT.
		 */
		if ((table_desc->loaded_into_namespace) &&
		    (table_desc->pointer->length ==
		     new_table_desc->pointer->length)
		    &&
		    (!ACPI_MEMCMP
		     (table_desc->pointer, new_table_desc->pointer,
		      new_table_desc->pointer->length))) {

			/* Match: this table is already installed */

			ACPI_DEBUG_PRINT((ACPI_DB_TABLES,
					  "Table [%4.4s] already installed: Rev %X OemTableId [%8.8s]\n",
					  new_table_desc->pointer->signature,
					  new_table_desc->pointer->revision,
					  new_table_desc->pointer->
					  oem_table_id));

			new_table_desc->owner_id = table_desc->owner_id;
			new_table_desc->installed_desc = table_desc;

			return_ACPI_STATUS(AE_ALREADY_EXISTS);
		}

		/* Get next table on the list */

		table_desc = table_desc->next;
	}

	return_ACPI_STATUS(AE_OK);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_tb_validate_table_header
 *
 * PARAMETERS:  table_header        - Logical pointer to the table
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Check an ACPI table header for validity
 *
 * NOTE:  Table pointers are validated as follows:
 *          1) Table pointer must point to valid physical memory
 *          2) Signature must be 4 ASCII chars, even if we don't recognize the
 *             name
 *          3) Table must be readable for length specified in the header
 *          4) Table checksum must be valid (with the exception of the FACS
 *              which has no checksum because it contains variable fields)
 *
 ******************************************************************************/

acpi_status
acpi_tb_validate_table_header(struct acpi_table_header *table_header)
{
	acpi_name signature;

	ACPI_FUNCTION_ENTRY();

	/* Verify that this is a valid address */

	if (!acpi_os_readable(table_header, sizeof(struct acpi_table_header))) {
		ACPI_ERROR((AE_INFO,
			    "Cannot read table header at %p", table_header));

		return (AE_BAD_ADDRESS);
	}

	/* Ensure that the signature is 4 ASCII characters */

	ACPI_MOVE_32_TO_32(&signature, table_header->signature);
	if (!acpi_ut_valid_acpi_name(signature)) {
		ACPI_ERROR((AE_INFO,
			    "Table signature at %p [%p] has invalid characters",
			    table_header, &signature));

		ACPI_WARNING((AE_INFO, "Invalid table signature found: [%4.4s]",
			      ACPI_CAST_PTR(char, &signature)));

		ACPI_DUMP_BUFFER(table_header,
				 sizeof(struct acpi_table_header));
		return (AE_BAD_SIGNATURE);
	}

	/* Validate the table length */

	if (table_header->length < sizeof(struct acpi_table_header)) {
		ACPI_ERROR((AE_INFO,
			    "Invalid length in table header %p name %4.4s",
			    table_header, (char *)&signature));

		ACPI_WARNING((AE_INFO,
			      "Invalid table header length (0x%X) found",
			      (u32) table_header->length));

		ACPI_DUMP_BUFFER(table_header,
				 sizeof(struct acpi_table_header));
		return (AE_BAD_HEADER);
	}

	return (AE_OK);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_tb_sum_table
 *
 * PARAMETERS:  Buffer              - Buffer to sum
 *              Length              - Size of the buffer
 *
 * RETURN:      8 bit sum of buffer
 *
 * DESCRIPTION: Computes an 8 bit sum of the buffer(length) and returns it.
 *
 ******************************************************************************/

u8 acpi_tb_sum_table(void *buffer, u32 length)
{
	acpi_native_uint i;
	u8 sum = 0;

	if (!buffer || !length) {
		return (0);
	}

	for (i = 0; i < length; i++) {
		sum = (u8) (sum + ((u8 *) buffer)[i]);
	}
	return (sum);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_tb_generate_checksum
 *
 * PARAMETERS:  Table               - Pointer to a valid ACPI table (with a
 *                                    standard ACPI header)
 *
 * RETURN:      8 bit checksum of buffer
 *
 * DESCRIPTION: Computes an 8 bit checksum of the table.
 *
 ******************************************************************************/

u8 acpi_tb_generate_checksum(struct acpi_table_header * table)
{
	u8 checksum;

	/* Sum the entire table as-is */

	checksum = acpi_tb_sum_table(table, table->length);

	/* Subtract off the existing checksum value in the table */

	checksum = (u8) (checksum - table->checksum);

	/* Compute the final checksum */

	checksum = (u8) (0 - checksum);
	return (checksum);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_tb_set_checksum
 *
 * PARAMETERS:  Table               - Pointer to a valid ACPI table (with a
 *                                    standard ACPI header)
 *
 * RETURN:      None. Sets the table checksum field
 *
 * DESCRIPTION: Computes an 8 bit checksum of the table and inserts the
 *              checksum into the table header.
 *
 ******************************************************************************/

void acpi_tb_set_checksum(struct acpi_table_header *table)
{

	table->checksum = acpi_tb_generate_checksum(table);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_tb_verify_table_checksum
 *
 * PARAMETERS:  *table_header           - ACPI table to verify
 *
 * RETURN:      8 bit checksum of table
 *
 * DESCRIPTION: Generates an 8 bit checksum of table and returns and compares
 *              it to the existing checksum value.
 *
 ******************************************************************************/

acpi_status
acpi_tb_verify_table_checksum(struct acpi_table_header *table_header)
{
	u8 checksum;

	ACPI_FUNCTION_TRACE(tb_verify_table_checksum);

	/* Compute the checksum on the table */

	checksum = acpi_tb_generate_checksum(table_header);

	/* Checksum ok? */

	if (checksum == table_header->checksum) {
		return_ACPI_STATUS(AE_OK);
	}

	ACPI_WARNING((AE_INFO,
		      "Incorrect checksum in table [%4.4s] - is %2.2X, should be %2.2X",
		      table_header->signature, table_header->checksum,
		      checksum));

	return_ACPI_STATUS(AE_BAD_CHECKSUM);
}

#ifdef ACPI_OBSOLETE_FUNCTIONS
/*******************************************************************************
 *
 * FUNCTION:    acpi_tb_handle_to_object
 *
 * PARAMETERS:  table_id            - Id for which the function is searching
 *              table_desc          - Pointer to return the matching table
 *                                      descriptor.
 *
 * RETURN:      Search the tables to find one with a matching table_id and
 *              return a pointer to that table descriptor.
 *
 ******************************************************************************/

acpi_status
acpi_tb_handle_to_object(u16 table_id,
			 struct acpi_table_desc **return_table_desc)
{
	u32 i;
	struct acpi_table_desc *table_desc;

	ACPI_FUNCTION_NAME(tb_handle_to_object);

	for (i = 0; i < ACPI_TABLE_MAX; i++) {
		table_desc = acpi_gbl_table_lists[i].next;
		while (table_desc) {
			if (table_desc->table_id == table_id) {
				*return_table_desc = table_desc;
				return (AE_OK);
			}

			table_desc = table_desc->next;
		}
	}

	ACPI_ERROR((AE_INFO, "TableId=%X does not exist", table_id));
	return (AE_BAD_PARAMETER);
}
#endif