drivers/acpi/acpica/exnames.c

   1 /******************************************************************************
   2  *
   3  * Module Name: exnames - interpreter/scanner name load/execute
   4  *
   5  *****************************************************************************/
   6
   7 /*
   8  * Copyright (C) 2000 - 2018, 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;
 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
 168          * at a 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         for (index = 0;
 178              (index < ACPI_NAME_SIZE)
 179              && (acpi_ut_valid_name_char(*aml_address, 0)); index++) {
 180                 char_buf[index] = *aml_address++;
 181         }
 182
 183         /* Valid name segment  */
 184
 185         if (index == 4) {
 186
 187                 /* Found 4 valid characters */
 188
 189                 char_buf[4] = '\0';
 190
 191                 if (name_string) {
 192                         ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 193                                           "Appending NameSeg %s\n", char_buf));
 194                         strcat(name_string, char_buf);
 195                 } else {
 196                         ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 197                                           "No Name string - %s\n", char_buf));
 198                 }
 199         } else if (index == 0) {
 200                 /*
 201                  * First character was not a valid name character,
 202                  * so we are looking at something other than a name.
 203                  */
 204                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 205                                   "Leading character is not alpha: %02Xh (not a name)\n",
 206                                   char_buf[0]));
 207                 status = AE_CTRL_PENDING;
 208         } else {
 209                 /*
 210                  * Segment started with one or more valid characters, but fewer than
 211                  * the required 4
 212                  */
 213                 status = AE_AML_BAD_NAME;
 214                 ACPI_ERROR((AE_INFO,
 215                             "Bad character 0x%02x in name, at %p",
 216                             *aml_address, aml_address));
 217         }
 218
 219         *in_aml_address = ACPI_CAST_PTR(u8, aml_address);
 220         return_ACPI_STATUS(status);
 221 }
 222
 223 /*******************************************************************************
 224  *
 225  * FUNCTION:    acpi_ex_get_name_string
 226  *
 227  * PARAMETERS:  data_type           - Object type to be associated with this
 228  *                                    name
 229  *              in_aml_address      - Pointer to the namestring in the AML code
 230  *              out_name_string     - Where the namestring is returned
 231  *              out_name_length     - Length of the returned string
 232  *
 233  * RETURN:      Status, namestring and length
 234  *
 235  * DESCRIPTION: Extract a full namepath from the AML byte stream,
 236  *              including any prefixes.
 237  *
 238  ******************************************************************************/
 239
 240 acpi_status
 241 acpi_ex_get_name_string(acpi_object_type data_type,
 242                         u8 * in_aml_address,
 243                         char **out_name_string, u32 * out_name_length)
 244 {
 245         acpi_status status = AE_OK;
 246         u8 *aml_address = in_aml_address;
 247         char *name_string = NULL;
 248         u32 num_segments;
 249         u32 prefix_count = 0;
 250         u8 has_prefix = FALSE;
 251
 252         ACPI_FUNCTION_TRACE_PTR(ex_get_name_string, aml_address);
 253
 254         if (ACPI_TYPE_LOCAL_REGION_FIELD == data_type ||
 255             ACPI_TYPE_LOCAL_BANK_FIELD == data_type ||
 256             ACPI_TYPE_LOCAL_INDEX_FIELD == data_type) {
 257
 258                 /* Disallow prefixes for types associated with field_unit names */
 259
 260                 name_string = acpi_ex_allocate_name_string(0, 1);
 261                 if (!name_string) {
 262                         status = AE_NO_MEMORY;
 263                 } else {
 264                         status =
 265                             acpi_ex_name_segment(&aml_address, name_string);
 266                 }
 267         } else {
 268                 /*
 269                  * data_type is not a field name.
 270                  * Examine first character of name for root or parent prefix operators
 271                  */
 272                 switch (*aml_address) {
 273                 case AML_ROOT_PREFIX:
 274
 275                         ACPI_DEBUG_PRINT((ACPI_DB_LOAD,
 276                                           "RootPrefix(\\) at %p\n",
 277                                           aml_address));
 278
 279                         /*
 280                          * Remember that we have a root_prefix --
 281                          * see comment in acpi_ex_allocate_name_string()
 282                          */
 283                         aml_address++;
 284                         prefix_count = ACPI_UINT32_MAX;
 285                         has_prefix = TRUE;
 286                         break;
 287
 288                 case AML_PARENT_PREFIX:
 289
 290                         /* Increment past possibly multiple parent prefixes */
 291
 292                         do {
 293                                 ACPI_DEBUG_PRINT((ACPI_DB_LOAD,
 294                                                   "ParentPrefix (^) at %p\n",
 295                                                   aml_address));
 296
 297                                 aml_address++;
 298                                 prefix_count++;
 299
 300                         } while (*aml_address == AML_PARENT_PREFIX);
 301
 302                         has_prefix = TRUE;
 303                         break;
 304
 305                 default:
 306
 307                         /* Not a prefix character */
 308
 309                         break;
 310                 }
 311
 312                 /* Examine first character of name for name segment prefix operator */
 313
 314                 switch (*aml_address) {
 315                 case AML_DUAL_NAME_PREFIX:
 316
 317                         ACPI_DEBUG_PRINT((ACPI_DB_LOAD,
 318                                           "DualNamePrefix at %p\n",
 319                                           aml_address));
 320
 321                         aml_address++;
 322                         name_string =
 323                             acpi_ex_allocate_name_string(prefix_count, 2);
 324                         if (!name_string) {
 325                                 status = AE_NO_MEMORY;
 326                                 break;
 327                         }
 328
 329                         /* Indicate that we processed a prefix */
 330
 331                         has_prefix = TRUE;
 332
 333                         status =
 334                             acpi_ex_name_segment(&aml_address, name_string);
 335                         if (ACPI_SUCCESS(status)) {
 336                                 status =
 337                                     acpi_ex_name_segment(&aml_address,
 338                                                          name_string);
 339                         }
 340                         break;
 341
 342                 case AML_MULTI_NAME_PREFIX:
 343
 344                         ACPI_DEBUG_PRINT((ACPI_DB_LOAD,
 345                                           "MultiNamePrefix at %p\n",
 346                                           aml_address));
 347
 348                         /* Fetch count of segments remaining in name path */
 349
 350                         aml_address++;
 351                         num_segments = *aml_address;
 352
 353                         name_string =
 354                             acpi_ex_allocate_name_string(prefix_count,
 355                                                          num_segments);
 356                         if (!name_string) {
 357                                 status = AE_NO_MEMORY;
 358                                 break;
 359                         }
 360
 361                         /* Indicate that we processed a prefix */
 362
 363                         aml_address++;
 364                         has_prefix = TRUE;
 365
 366                         while (num_segments &&
 367                                (status =
 368                                 acpi_ex_name_segment(&aml_address,
 369                                                      name_string)) == AE_OK) {
 370                                 num_segments--;
 371                         }
 372
 373                         break;
 374
 375                 case 0:
 376
 377                         /* null_name valid as of 8-12-98 ASL/AML Grammar Update */
 378
 379                         if (prefix_count == ACPI_UINT32_MAX) {
 380                                 ACPI_DEBUG_PRINT((ACPI_DB_EXEC,
 381                                                   "NameSeg is \"\\\" followed by NULL\n"));
 382                         }
 383
 384                         /* Consume the NULL byte */
 385
 386                         aml_address++;
 387                         name_string =
 388                             acpi_ex_allocate_name_string(prefix_count, 0);
 389                         if (!name_string) {
 390                                 status = AE_NO_MEMORY;
 391                                 break;
 392                         }
 393
 394                         break;
 395
 396                 default:
 397
 398                         /* Name segment string */
 399
 400                         name_string =
 401                             acpi_ex_allocate_name_string(prefix_count, 1);
 402                         if (!name_string) {
 403                                 status = AE_NO_MEMORY;
 404                                 break;
 405                         }
 406
 407                         status =
 408                             acpi_ex_name_segment(&aml_address, name_string);
 409                         break;
 410                 }
 411         }
 412
 413         if (AE_CTRL_PENDING == status && has_prefix) {
 414
 415                 /* Ran out of segments after processing a prefix */
 416
 417                 ACPI_ERROR((AE_INFO, "Malformed Name at %p", name_string));
 418                 status = AE_AML_BAD_NAME;
 419         }
 420
 421         if (ACPI_FAILURE(status)) {
 422                 if (name_string) {
 423                         ACPI_FREE(name_string);
 424                 }
 425                 return_ACPI_STATUS(status);
 426         }
 427
 428         *out_name_string = name_string;
 429         *out_name_length = (u32) (aml_address - in_aml_address);
 430
 431         return_ACPI_STATUS(status);
 432 }