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psargs.c

/******************************************************************************
 *
 * Module Name: psargs - Parse AML opcode arguments
 *
 *****************************************************************************/

/*
 * Copyright (C) 2000 - 2007, 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/acparser.h>
#include <acpi/amlcode.h>
#include <acpi/acnamesp.h>
#include <acpi/acdispat.h>

#define _COMPONENT          ACPI_PARSER
ACPI_MODULE_NAME("psargs")

/* Local prototypes */
static u32
acpi_ps_get_next_package_length(struct acpi_parse_state *parser_state);

static union acpi_parse_object *acpi_ps_get_next_field(struct acpi_parse_state
                                           *parser_state);

/*******************************************************************************
 *
 * FUNCTION:    acpi_ps_get_next_package_length
 *
 * PARAMETERS:  parser_state        - Current parser state object
 *
 * RETURN:      Decoded package length. On completion, the AML pointer points
 *              past the length byte or bytes.
 *
 * DESCRIPTION: Decode and return a package length field.
 *              Note: Largest package length is 28 bits, from ACPI specification
 *
 ******************************************************************************/

static u32
acpi_ps_get_next_package_length(struct acpi_parse_state *parser_state)
{
      u8 *aml = parser_state->aml;
      u32 package_length = 0;
      acpi_native_uint byte_count;
      u8 byte_zero_mask = 0x3F;     /* Default [0:5] */

      ACPI_FUNCTION_TRACE(ps_get_next_package_length);

      /*
       * Byte 0 bits [6:7] contain the number of additional bytes
       * used to encode the package length, either 0,1,2, or 3
       */
      byte_count = (aml[0] >> 6);
      parser_state->aml += (byte_count + 1);

      /* Get bytes 3, 2, 1 as needed */

      while (byte_count) {
            /*
             * Final bit positions for the package length bytes:
             *      Byte3->[20:27]
             *      Byte2->[12:19]
             *      Byte1->[04:11]
             *      Byte0->[00:03]
             */
            package_length |= (aml[byte_count] << ((byte_count << 3) - 4));

            byte_zero_mask = 0x0F;  /* Use bits [0:3] of byte 0 */
            byte_count--;
      }

      /* Byte 0 is a special case, either bits [0:3] or [0:5] are used */

      package_length |= (aml[0] & byte_zero_mask);
      return_UINT32(package_length);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ps_get_next_package_end
 *
 * PARAMETERS:  parser_state        - Current parser state object
 *
 * RETURN:      Pointer to end-of-package +1
 *
 * DESCRIPTION: Get next package length and return a pointer past the end of
 *              the package.  Consumes the package length field
 *
 ******************************************************************************/

u8 *acpi_ps_get_next_package_end(struct acpi_parse_state *parser_state)
{
      u8 *start = parser_state->aml;
      u32 package_length;

      ACPI_FUNCTION_TRACE(ps_get_next_package_end);

      /* Function below updates parser_state->Aml */

      package_length = acpi_ps_get_next_package_length(parser_state);

      return_PTR(start + package_length); /* end of package */
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ps_get_next_namestring
 *
 * PARAMETERS:  parser_state        - Current parser state object
 *
 * RETURN:      Pointer to the start of the name string (pointer points into
 *              the AML.
 *
 * DESCRIPTION: Get next raw namestring within the AML stream.  Handles all name
 *              prefix characters.  Set parser state to point past the string.
 *              (Name is consumed from the AML.)
 *
 ******************************************************************************/

char *acpi_ps_get_next_namestring(struct acpi_parse_state *parser_state)
{
      u8 *start = parser_state->aml;
      u8 *end = parser_state->aml;

      ACPI_FUNCTION_TRACE(ps_get_next_namestring);

      /* Point past any namestring prefix characters (backslash or carat) */

      while (acpi_ps_is_prefix_char(*end)) {
            end++;
      }

      /* Decode the path prefix character */

      switch (*end) {
      case 0:

            /* null_name */

            if (end == start) {
                  start = NULL;
            }
            end++;
            break;

      case AML_DUAL_NAME_PREFIX:

            /* Two name segments */

            end += 1 + (2 * ACPI_NAME_SIZE);
            break;

      case AML_MULTI_NAME_PREFIX_OP:

            /* Multiple name segments, 4 chars each, count in next byte */

            end += 2 + (*(end + 1) * ACPI_NAME_SIZE);
            break;

      default:

            /* Single name segment */

            end += ACPI_NAME_SIZE;
            break;
      }

      parser_state->aml = end;
      return_PTR((char *)start);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ps_get_next_namepath
 *
 * PARAMETERS:  parser_state        - Current parser state object
 *              Arg                 - Where the namepath will be stored
 *              arg_count           - If the namepath points to a control method
 *                                    the method's argument is returned here.
 *              possible_method_call - Whether the namepath can possibly be the
 *                                    start of a method call
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Get next name (if method call, return # of required args).
 *              Names are looked up in the internal namespace to determine
 *              if the name represents a control method.  If a method
 *              is found, the number of arguments to the method is returned.
 *              This information is critical for parsing to continue correctly.
 *
 ******************************************************************************/

acpi_status
acpi_ps_get_next_namepath(struct acpi_walk_state *walk_state,
                    struct acpi_parse_state *parser_state,
                    union acpi_parse_object *arg, u8 possible_method_call)
{
      char *path;
      union acpi_parse_object *name_op;
      acpi_status status;
      union acpi_operand_object *method_desc;
      struct acpi_namespace_node *node;
      union acpi_generic_state scope_info;

      ACPI_FUNCTION_TRACE(ps_get_next_namepath);

      path = acpi_ps_get_next_namestring(parser_state);
      acpi_ps_init_op(arg, AML_INT_NAMEPATH_OP);

      /* Null path case is allowed, just exit */

      if (!path) {
            arg->common.value.name = path;
            return_ACPI_STATUS(AE_OK);
      }

      /* Setup search scope info */

      scope_info.scope.node = NULL;
      node = parser_state->start_node;
      if (node) {
            scope_info.scope.node = node;
      }

      /*
       * Lookup the name in the internal namespace. We don't want to add
       * anything new to the namespace here, however, so we use MODE_EXECUTE.
       * Allow searching of the parent tree, but don't open a new scope -
       * we just want to lookup the object (must be mode EXECUTE to perform
       * the upsearch)
       */
      status =
          acpi_ns_lookup(&scope_info, path, ACPI_TYPE_ANY, ACPI_IMODE_EXECUTE,
                     ACPI_NS_SEARCH_PARENT | ACPI_NS_DONT_OPEN_SCOPE,
                     NULL, &node);

      /*
       * If this name is a control method invocation, we must
       * setup the method call
       */
      if (ACPI_SUCCESS(status) &&
          possible_method_call && (node->type == ACPI_TYPE_METHOD)) {

            /* This name is actually a control method invocation */

            method_desc = acpi_ns_get_attached_object(node);
            ACPI_DEBUG_PRINT((ACPI_DB_PARSE,
                          "Control Method - %p Desc %p Path=%p\n", node,
                          method_desc, path));

            name_op = acpi_ps_alloc_op(AML_INT_NAMEPATH_OP);
            if (!name_op) {
                  return_ACPI_STATUS(AE_NO_MEMORY);
            }

            /* Change Arg into a METHOD CALL and attach name to it */

            acpi_ps_init_op(arg, AML_INT_METHODCALL_OP);
            name_op->common.value.name = path;

            /* Point METHODCALL/NAME to the METHOD Node */

            name_op->common.node = node;
            acpi_ps_append_arg(arg, name_op);

            if (!method_desc) {
                  ACPI_ERROR((AE_INFO,
                            "Control Method %p has no attached object",
                            node));
                  return_ACPI_STATUS(AE_AML_INTERNAL);
            }

            ACPI_DEBUG_PRINT((ACPI_DB_PARSE,
                          "Control Method - %p Args %X\n",
                          node, method_desc->method.param_count));

            /* Get the number of arguments to expect */

            walk_state->arg_count = method_desc->method.param_count;
            return_ACPI_STATUS(AE_OK);
      }

      /*
       * Special handling if the name was not found during the lookup -
       * some not_found cases are allowed
       */
      if (status == AE_NOT_FOUND) {

            /* 1) not_found is ok during load pass 1/2 (allow forward references) */

            if ((walk_state->parse_flags & ACPI_PARSE_MODE_MASK) !=
                ACPI_PARSE_EXECUTE) {
                  status = AE_OK;
            }

            /* 2) not_found during a cond_ref_of(x) is ok by definition */

            else if (walk_state->op->common.aml_opcode ==
                   AML_COND_REF_OF_OP) {
                  status = AE_OK;
            }

            /*
             * 3) not_found while building a Package is ok at this point, we
             * may flag as an error later if slack mode is not enabled.
             * (Some ASL code depends on allowing this behavior)
             */
            else if ((arg->common.parent) &&
                   ((arg->common.parent->common.aml_opcode ==
                     AML_PACKAGE_OP)
                    || (arg->common.parent->common.aml_opcode ==
                        AML_VAR_PACKAGE_OP))) {
                  status = AE_OK;
            }
      }

      /* Final exception check (may have been changed from code above) */

      if (ACPI_FAILURE(status)) {
            ACPI_ERROR_NAMESPACE(path, status);

            if ((walk_state->parse_flags & ACPI_PARSE_MODE_MASK) ==
                ACPI_PARSE_EXECUTE) {

                  /* Report a control method execution error */

                  status = acpi_ds_method_error(status, walk_state);
            }
      }

      /* Save the namepath */

      arg->common.value.name = path;
      return_ACPI_STATUS(status);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ps_get_next_simple_arg
 *
 * PARAMETERS:  parser_state        - Current parser state object
 *              arg_type            - The argument type (AML_*_ARG)
 *              Arg                 - Where the argument is returned
 *
 * RETURN:      None
 *
 * DESCRIPTION: Get the next simple argument (constant, string, or namestring)
 *
 ******************************************************************************/

void
acpi_ps_get_next_simple_arg(struct acpi_parse_state *parser_state,
                      u32 arg_type, union acpi_parse_object *arg)
{
      u32 length;
      u16 opcode;
      u8 *aml = parser_state->aml;

      ACPI_FUNCTION_TRACE_U32(ps_get_next_simple_arg, arg_type);

      switch (arg_type) {
      case ARGP_BYTEDATA:

            /* Get 1 byte from the AML stream */

            opcode = AML_BYTE_OP;
            arg->common.value.integer = (acpi_integer) * aml;
            length = 1;
            break;

      case ARGP_WORDDATA:

            /* Get 2 bytes from the AML stream */

            opcode = AML_WORD_OP;
            ACPI_MOVE_16_TO_64(&arg->common.value.integer, aml);
            length = 2;
            break;

      case ARGP_DWORDDATA:

            /* Get 4 bytes from the AML stream */

            opcode = AML_DWORD_OP;
            ACPI_MOVE_32_TO_64(&arg->common.value.integer, aml);
            length = 4;
            break;

      case ARGP_QWORDDATA:

            /* Get 8 bytes from the AML stream */

            opcode = AML_QWORD_OP;
            ACPI_MOVE_64_TO_64(&arg->common.value.integer, aml);
            length = 8;
            break;

      case ARGP_CHARLIST:

            /* Get a pointer to the string, point past the string */

            opcode = AML_STRING_OP;
            arg->common.value.string = ACPI_CAST_PTR(char, aml);

            /* Find the null terminator */

            length = 0;
            while (aml[length]) {
                  length++;
            }
            length++;
            break;

      case ARGP_NAME:
      case ARGP_NAMESTRING:

            acpi_ps_init_op(arg, AML_INT_NAMEPATH_OP);
            arg->common.value.name =
                acpi_ps_get_next_namestring(parser_state);
            return_VOID;

      default:

            ACPI_ERROR((AE_INFO, "Invalid ArgType %X", arg_type));
            return_VOID;
      }

      acpi_ps_init_op(arg, opcode);
      parser_state->aml += length;
      return_VOID;
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ps_get_next_field
 *
 * PARAMETERS:  parser_state        - Current parser state object
 *
 * RETURN:      A newly allocated FIELD op
 *
 * DESCRIPTION: Get next field (named_field, reserved_field, or access_field)
 *
 ******************************************************************************/

static union acpi_parse_object *acpi_ps_get_next_field(struct acpi_parse_state
                                           *parser_state)
{
      u32 aml_offset = (u32)
          ACPI_PTR_DIFF(parser_state->aml,
                    parser_state->aml_start);
      union acpi_parse_object *field;
      u16 opcode;
      u32 name;

      ACPI_FUNCTION_TRACE(ps_get_next_field);

      /* Determine field type */

      switch (ACPI_GET8(parser_state->aml)) {
      default:

            opcode = AML_INT_NAMEDFIELD_OP;
            break;

      case 0x00:

            opcode = AML_INT_RESERVEDFIELD_OP;
            parser_state->aml++;
            break;

      case 0x01:

            opcode = AML_INT_ACCESSFIELD_OP;
            parser_state->aml++;
            break;
      }

      /* Allocate a new field op */

      field = acpi_ps_alloc_op(opcode);
      if (!field) {
            return_PTR(NULL);
      }

      field->common.aml_offset = aml_offset;

      /* Decode the field type */

      switch (opcode) {
      case AML_INT_NAMEDFIELD_OP:

            /* Get the 4-character name */

            ACPI_MOVE_32_TO_32(&name, parser_state->aml);
            acpi_ps_set_name(field, name);
            parser_state->aml += ACPI_NAME_SIZE;

            /* Get the length which is encoded as a package length */

            field->common.value.size =
                acpi_ps_get_next_package_length(parser_state);
            break;

      case AML_INT_RESERVEDFIELD_OP:

            /* Get the length which is encoded as a package length */

            field->common.value.size =
                acpi_ps_get_next_package_length(parser_state);
            break;

      case AML_INT_ACCESSFIELD_OP:

            /*
             * Get access_type and access_attrib and merge into the field Op
             * access_type is first operand, access_attribute is second
             */
            field->common.value.integer =
                (((u32) ACPI_GET8(parser_state->aml) << 8));
            parser_state->aml++;
            field->common.value.integer |= ACPI_GET8(parser_state->aml);
            parser_state->aml++;
            break;

      default:

            /* Opcode was set in previous switch */
            break;
      }

      return_PTR(field);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ps_get_next_arg
 *
 * PARAMETERS:  walk_state          - Current state
 *              parser_state        - Current parser state object
 *              arg_type            - The argument type (AML_*_ARG)
 *              return_arg          - Where the next arg is returned
 *
 * RETURN:      Status, and an op object containing the next argument.
 *
 * DESCRIPTION: Get next argument (including complex list arguments that require
 *              pushing the parser stack)
 *
 ******************************************************************************/

acpi_status
acpi_ps_get_next_arg(struct acpi_walk_state *walk_state,
                 struct acpi_parse_state *parser_state,
                 u32 arg_type, union acpi_parse_object **return_arg)
{
      union acpi_parse_object *arg = NULL;
      union acpi_parse_object *prev = NULL;
      union acpi_parse_object *field;
      u32 subop;
      acpi_status status = AE_OK;

      ACPI_FUNCTION_TRACE_PTR(ps_get_next_arg, parser_state);

      switch (arg_type) {
      case ARGP_BYTEDATA:
      case ARGP_WORDDATA:
      case ARGP_DWORDDATA:
      case ARGP_CHARLIST:
      case ARGP_NAME:
      case ARGP_NAMESTRING:

            /* Constants, strings, and namestrings are all the same size */

            arg = acpi_ps_alloc_op(AML_BYTE_OP);
            if (!arg) {
                  return_ACPI_STATUS(AE_NO_MEMORY);
            }
            acpi_ps_get_next_simple_arg(parser_state, arg_type, arg);
            break;

      case ARGP_PKGLENGTH:

            /* Package length, nothing returned */

            parser_state->pkg_end =
                acpi_ps_get_next_package_end(parser_state);
            break;

      case ARGP_FIELDLIST:

            if (parser_state->aml < parser_state->pkg_end) {

                  /* Non-empty list */

                  while (parser_state->aml < parser_state->pkg_end) {
                        field = acpi_ps_get_next_field(parser_state);
                        if (!field) {
                              return_ACPI_STATUS(AE_NO_MEMORY);
                        }

                        if (prev) {
                              prev->common.next = field;
                        } else {
                              arg = field;
                        }
                        prev = field;
                  }

                  /* Skip to End of byte data */

                  parser_state->aml = parser_state->pkg_end;
            }
            break;

      case ARGP_BYTELIST:

            if (parser_state->aml < parser_state->pkg_end) {

                  /* Non-empty list */

                  arg = acpi_ps_alloc_op(AML_INT_BYTELIST_OP);
                  if (!arg) {
                        return_ACPI_STATUS(AE_NO_MEMORY);
                  }

                  /* Fill in bytelist data */

                  arg->common.value.size = (u32)
                      ACPI_PTR_DIFF(parser_state->pkg_end,
                                parser_state->aml);
                  arg->named.data = parser_state->aml;

                  /* Skip to End of byte data */

                  parser_state->aml = parser_state->pkg_end;
            }
            break;

      case ARGP_TARGET:
      case ARGP_SUPERNAME:
      case ARGP_SIMPLENAME:

            subop = acpi_ps_peek_opcode(parser_state);
            if (subop == 0 ||
                acpi_ps_is_leading_char(subop) ||
                acpi_ps_is_prefix_char(subop)) {

                  /* null_name or name_string */

                  arg = acpi_ps_alloc_op(AML_INT_NAMEPATH_OP);
                  if (!arg) {
                        return_ACPI_STATUS(AE_NO_MEMORY);
                  }

                  status =
                      acpi_ps_get_next_namepath(walk_state, parser_state,
                                          arg, 0);
            } else {
                  /* Single complex argument, nothing returned */

                  walk_state->arg_count = 1;
            }
            break;

      case ARGP_DATAOBJ:
      case ARGP_TERMARG:

            /* Single complex argument, nothing returned */

            walk_state->arg_count = 1;
            break;

      case ARGP_DATAOBJLIST:
      case ARGP_TERMLIST:
      case ARGP_OBJLIST:

            if (parser_state->aml < parser_state->pkg_end) {

                  /* Non-empty list of variable arguments, nothing returned */

                  walk_state->arg_count = ACPI_VAR_ARGS;
            }
            break;

      default:

            ACPI_ERROR((AE_INFO, "Invalid ArgType: %X", arg_type));
            status = AE_AML_OPERAND_TYPE;
            break;
      }

      *return_arg = arg;
      return_ACPI_STATUS(status);
}

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