drivers/acpi/acpica/exnames.c

   1 /******************************************************************************
   2  *
   3  * Module Name: exnames - interpreter/scanner name load/execute
   4  *
   5  *****************************************************************************/
   6
   7 /*
   8  * Copyright (C) 2000 - 2013, Intel Corp.
   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 #include <acpi/acpi.h>
  45 #include "accommon.h"
  46 #include "acinterp.h"
  47 #include "amlcode.h"
  48
  49 #define _COMPONENT          ACPI_EXECUTER
  50 ACPI_MODULE_NAME("exnames")
  51
  52 /* Local prototypes */
  53 static char *acpi_ex_allocate_name_string(u32 prefix_count, u32 num_name_segs);
  54
  55 static acpi_status acpi_ex_name_segment(u8 **in_aml_address, char *name_string);
  56
  57 /*******************************************************************************
  58  *
  59  * FUNCTION:    acpi_ex_allocate_name_string
  60  *
  61  * PARAMETERS:  prefix_count        - Count of parent levels. Special cases:
  62  *                                    (-1)==root,  0==none
  63  *              num_name_segs       - count of 4-character name segments
  64  *
  65  * RETURN:      A pointer to the allocated string segment. This segment must
  66  *              be deleted by the caller.
  67  *
  68  * DESCRIPTION: Allocate a buffer for a name string. Ensure allocated name
  69  *              string is long enough, and set up prefix if any.
  70  *
  71  ******************************************************************************/
  72
  73 static char *acpi_ex_allocate_name_string(u32 prefix_count, u32 num_name_segs)
  74 {
  75         char *temp_ptr;
  76         char *name_string;
  77         u32 size_needed;
  78
  79         ACPI_FUNCTION_TRACE(ex_allocate_name_string);
  80
  81         /*
  82          * Allow room for all \ and ^ prefixes, all segments and a multi_name_prefix.
  83          * Also, one byte for the null terminator.
  84          * This may actually be somewhat longer than needed.
  85          */
  86         if (prefix_count == ACPI_UINT32_MAX) {
  87
  88                 /* Special case for root */
  89
  90                 size_needed = 1 + (ACPI_NAME_SIZE * num_name_segs) + 2 + 1;
  91         } else {
  92                 size_needed =
  93                     prefix_count + (ACPI_NAME_SIZE * num_name_segs) + 2 + 1;
  94         }
  95
  96         /*
  97          * Allocate a buffer for the name.
  98          * This buffer must be deleted by the caller!
  99          */
 100         name_string = ACPI_ALLOCATE(size_needed);
 101         if (!name_string) {
 102                 ACPI_ERROR((AE_INFO,
 103                             "Could not allocate size %u", size_needed));
 104                 return_PTR(NULL);
 105         }
 106
 107         temp_ptr = name_string;
 108
 109         /* Set up Root or Parent prefixes if needed */
 110
 111         if (prefix_count == ACPI_UINT32_MAX) {
 112                 *temp_ptr++ = AML_ROOT_PREFIX;
 113         } else {
 114                 while (prefix_count--) {
 115                         *temp_ptr++ = AML_PARENT_PREFIX;
 116                 }
 117         }
 118
 119         /* Set up Dual or Multi prefixes if needed */
 120
 121         if (num_name_segs > 2) {
 122
 123                 /* Set up multi prefixes   */
 124
 125                 *temp_ptr++ = AML_MULTI_NAME_PREFIX_OP;
 126                 *temp_ptr++ = (char)num_name_segs;
 127         } else if (2 == num_name_segs) {
 128
 129                 /* Set up dual prefixes */
 130
 131                 *temp_ptr++ = AML_DUAL_NAME_PREFIX;
 132         }
 133
 134         /*
 135          * Terminate string following prefixes. acpi_ex_name_segment() will
 136          * append the segment(s)
 137          */
 138         *temp_ptr = 0;
 139
 140         return_PTR(name_string);
 141 }
 142
 143 /*******************************************************************************
 144  *
 145  * FUNCTION:    acpi_ex_name_segment
 146  *
 147  * PARAMETERS:  in_aml_address  - Pointer to the name in the AML code
 148  *              name_string     - Where to return the name. The name is appended
 149  *                                to any existing string to form a namepath
 150  *
 151  * RETURN:      Status
 152  *
 153  * DESCRIPTION: Extract an ACPI name (4 bytes) from the AML byte stream
 154  *
 155  ******************************************************************************/
 156
 157 static acpi_status acpi_ex_name_segment(u8 ** in_aml_address, char *name_string)
 158 {
 159         char *aml_address = (void *)*in_aml_address;
 160         acpi_status status = AE_OK;
 161         u32 index;
 162         char char_buf[5];
 163
 164         ACPI_FUNCTION_TRACE(ex_name_segment);
 165
 166         /*
 167          * If first character is a digit, then we know that we aren't looking at a
 168          * valid name segment
 169          */
 170         char_buf[0] = *aml_address;
 171
 172         if ('0' <= char_buf[0] && char_buf[0] <= '9') {
 173                 ACPI_ERROR((AE_INFO, "Invalid leading digit: %c", char_buf[0]));
 174                 return_ACPI_STATUS(AE_CTRL_PENDING);
 175         }
 176
 177         ACPI_DEBUG_PRINT((ACPI_DB_LOAD, "Bytes from stream:\n"));
 178
 179         for (index = 0;
 180              (index < ACPI_NAME_SIZE)
 181              && (acpi_ut_valid_acpi_char(*aml_address, 0)); index++) {
 182                 char_buf[index] = *aml_address++;
 183                 ACPI_DEBUG_PRINT((ACPI_DB_LOAD, "%c\n", char_buf[index]));
 184         }
 185
 186         /* Valid name segment  */
 187
 188         if (index == 4) {
 189
 190                 /* Found 4 valid characters */
 191
 192                 char_buf[4] = '\0';
 193
 194                 if (name_string) {
 195                         ACPI_STRCAT(name_string, char_buf);
 196                         ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 197                                           "Appended to - %s\n", name_string));
 198                 } else {
 199                         ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 200                                           "No Name string - %s\n", char_buf));
 201                 }
 202         } else if (index == 0) {
 203                 /*
 204                  * First character was not a valid name character,
 205                  * so we are looking at something other than a name.
 206                  */
 207                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 208                                   "Leading character is not alpha: %02Xh (not a name)\n",
 209                                   char_buf[0]));
 210                 status = AE_CTRL_PENDING;
 211         } else {
 212                 /*
 213                  * Segment started with one or more valid characters, but fewer than
 214                  * the required 4
 215                  */
 216                 status = AE_AML_BAD_NAME;
 217                 ACPI_ERROR((AE_INFO,
 218                             "Bad character 0x%02x in name, at %p",
 219                             *aml_address, aml_address));
 220         }
 221
 222         *in_aml_address = ACPI_CAST_PTR(u8, aml_address);
 223         return_ACPI_STATUS(status);
 224 }
 225
 226 /*******************************************************************************
 227  *
 228  * FUNCTION:    acpi_ex_get_name_string
 229  *
 230  * PARAMETERS:  data_type           - Object type to be associated with this
 231  *                                    name
 232  *              in_aml_address      - Pointer to the namestring in the AML code
 233  *              out_name_string     - Where the namestring is returned
 234  *              out_name_length     - Length of the returned string
 235  *
 236  * RETURN:      Status, namestring and length
 237  *
 238  * DESCRIPTION: Extract a full namepath from the AML byte stream,
 239  *              including any prefixes.
 240  *
 241  ******************************************************************************/
 242
 243 acpi_status
 244 acpi_ex_get_name_string(acpi_object_type data_type,
 245                         u8 * in_aml_address,
 246                         char **out_name_string, u32 * out_name_length)
 247 {
 248         acpi_status status = AE_OK;
 249         u8 *aml_address = in_aml_address;
 250         char *name_string = NULL;
 251         u32 num_segments;
 252         u32 prefix_count = 0;
 253         u8 has_prefix = FALSE;
 254
 255         ACPI_FUNCTION_TRACE_PTR(ex_get_name_string, aml_address);
 256
 257         if (ACPI_TYPE_LOCAL_REGION_FIELD == data_type ||
 258             ACPI_TYPE_LOCAL_BANK_FIELD == data_type ||
 259             ACPI_TYPE_LOCAL_INDEX_FIELD == data_type) {
 260
 261                 /* Disallow prefixes for types associated with field_unit names */
 262
 263                 name_string = acpi_ex_allocate_name_string(0, 1);
 264                 if (!name_string) {
 265                         status = AE_NO_MEMORY;
 266                 } else {
 267                         status =
 268                             acpi_ex_name_segment(&aml_address, name_string);
 269                 }
 270         } else {
 271                 /*
 272                  * data_type is not a field name.
 273                  * Examine first character of name for root or parent prefix operators
 274                  */
 275                 switch (*aml_address) {
 276                 case AML_ROOT_PREFIX:
 277
 278                         ACPI_DEBUG_PRINT((ACPI_DB_LOAD,
 279                                           "RootPrefix(\\) at %p\n",
 280                                           aml_address));
 281
 282                         /*
 283                          * Remember that we have a root_prefix --
 284                          * see comment in acpi_ex_allocate_name_string()
 285                          */
 286                         aml_address++;
 287                         prefix_count = ACPI_UINT32_MAX;
 288                         has_prefix = TRUE;
 289                         break;
 290
 291                 case AML_PARENT_PREFIX:
 292
 293                         /* Increment past possibly multiple parent prefixes */
 294
 295                         do {
 296                                 ACPI_DEBUG_PRINT((ACPI_DB_LOAD,
 297                                                   "ParentPrefix (^) at %p\n",
 298                                                   aml_address));
 299
 300                                 aml_address++;
 301                                 prefix_count++;
 302
 303                         } while (*aml_address == AML_PARENT_PREFIX);
 304
 305                         has_prefix = TRUE;
 306                         break;
 307
 308                 default:
 309
 310                         /* Not a prefix character */
 311
 312                         break;
 313                 }
 314
 315                 /* Examine first character of name for name segment prefix operator */
 316
 317                 switch (*aml_address) {
 318                 case AML_DUAL_NAME_PREFIX:
 319
 320                         ACPI_DEBUG_PRINT((ACPI_DB_LOAD,
 321                                           "DualNamePrefix at %p\n",
 322                                           aml_address));
 323
 324                         aml_address++;
 325                         name_string =
 326                             acpi_ex_allocate_name_string(prefix_count, 2);
 327                         if (!name_string) {
 328                                 status = AE_NO_MEMORY;
 329                                 break;
 330                         }
 331
 332                         /* Indicate that we processed a prefix */
 333
 334                         has_prefix = TRUE;
 335
 336                         status =
 337                             acpi_ex_name_segment(&aml_address, name_string);
 338                         if (ACPI_SUCCESS(status)) {
 339                                 status =
 340                                     acpi_ex_name_segment(&aml_address,
 341                                                          name_string);
 342                         }
 343                         break;
 344
 345                 case AML_MULTI_NAME_PREFIX_OP:
 346
 347                         ACPI_DEBUG_PRINT((ACPI_DB_LOAD,
 348                                           "MultiNamePrefix at %p\n",
 349                                           aml_address));
 350
 351                         /* Fetch count of segments remaining in name path */
 352
 353                         aml_address++;
 354                         num_segments = *aml_address;
 355
 356                         name_string =
 357                             acpi_ex_allocate_name_string(prefix_count,
 358                                                          num_segments);
 359                         if (!name_string) {
 360                                 status = AE_NO_MEMORY;
 361                                 break;
 362                         }
 363
 364                         /* Indicate that we processed a prefix */
 365
 366                         aml_address++;
 367                         has_prefix = TRUE;
 368
 369                         while (num_segments &&
 370                                (status =
 371                                 acpi_ex_name_segment(&aml_address,
 372                                                      name_string)) == AE_OK) {
 373                                 num_segments--;
 374                         }
 375
 376                         break;
 377
 378                 case 0:
 379
 380                         /* null_name valid as of 8-12-98 ASL/AML Grammar Update */
 381
 382                         if (prefix_count == ACPI_UINT32_MAX) {
 383                                 ACPI_DEBUG_PRINT((ACPI_DB_EXEC,
 384                                                   "NameSeg is \"\\\" followed by NULL\n"));
 385                         }
 386
 387                         /* Consume the NULL byte */
 388
 389                         aml_address++;
 390                         name_string =
 391                             acpi_ex_allocate_name_string(prefix_count, 0);
 392                         if (!name_string) {
 393                                 status = AE_NO_MEMORY;
 394                                 break;
 395                         }
 396
 397                         break;
 398
 399                 default:
 400
 401                         /* Name segment string */
 402
 403                         name_string =
 404                             acpi_ex_allocate_name_string(prefix_count, 1);
 405                         if (!name_string) {
 406                                 status = AE_NO_MEMORY;
 407                                 break;
 408                         }
 409
 410                         status =
 411                             acpi_ex_name_segment(&aml_address, name_string);
 412                         break;
 413                 }
 414         }
 415
 416         if (AE_CTRL_PENDING == status && has_prefix) {
 417
 418                 /* Ran out of segments after processing a prefix */
 419
 420                 ACPI_ERROR((AE_INFO, "Malformed Name at %p", name_string));
 421                 status = AE_AML_BAD_NAME;
 422         }
 423
 424         if (ACPI_FAILURE(status)) {
 425                 if (name_string) {
 426                         ACPI_FREE(name_string);
 427                 }
 428                 return_ACPI_STATUS(status);
 429         }
 430
 431         *out_name_string = name_string;
 432         *out_name_length = (u32) (aml_address - in_aml_address);
 433
 434         return_ACPI_STATUS(status);
 435 }