Quelle  psloop.c   Sprache: C

// SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0
/******************************************************************************
 *
 * Module Name: psloop - Main AML parse loop
 *
 * Copyright (C) 2000 - 2025, Intel Corp.
 *
 *****************************************************************************/

/*
 * Parse the AML and build an operation tree as most interpreters, (such as
 * Perl) do. Parsing is done by hand rather than with a YACC generated parser
 * to tightly constrain stack and dynamic memory usage. Parsing is kept
 * flexible and the code fairly compact by parsing based on a list of AML
 * opcode templates in aml_op_info[].
 */

#include <acpi/acpi.h>
#include "accommon.h"
#include "acinterp.h"
#include "acparser.h"
#include "acdispat.h"
#include "amlcode.h"
#include "acconvert.h"
#include "acnamesp.h"

#define _COMPONENT          ACPI_PARSER
ACPI_MODULE_NAME("psloop")

/* Local prototypes */
static acpi_status
acpi_ps_get_arguments(struct acpi_walk_state *walk_state,
        u8 * aml_op_start, union acpi_parse_object *op);

/*******************************************************************************
 *
 * FUNCTION:    acpi_ps_get_arguments
 *
 * PARAMETERS:  walk_state          - Current state
 *              aml_op_start        - Op start in AML
 *              op                  - Current Op
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Get arguments for passed Op.
 *
 ******************************************************************************/

static acpi_status
acpi_ps_get_arguments(struct acpi_walk_state *walk_state,
        u8 * aml_op_start, union acpi_parse_object *op)
{
 acpi_status status = AE_OK;
 union acpi_parse_object *arg = NULL;

 ACPI_FUNCTION_TRACE_PTR(ps_get_arguments, walk_state);

 ACPI_DEBUG_PRINT((ACPI_DB_PARSE,
     "Get arguments for opcode [%s]\n",
     op->common.aml_op_name));

 switch (op->common.aml_opcode) {
 case AML_BYTE_OP: /* AML_BYTEDATA_ARG */
 case AML_WORD_OP: /* AML_WORDDATA_ARG */
 case AML_DWORD_OP: /* AML_DWORDATA_ARG */
 case AML_QWORD_OP: /* AML_QWORDATA_ARG */
 case AML_STRING_OP: /* AML_ASCIICHARLIST_ARG */

  /* Fill in constant or string argument directly */

  acpi_ps_get_next_simple_arg(&(walk_state->parser_state),
         GET_CURRENT_ARG_TYPE(walk_state->
         arg_types),
         op);
  break;

 case AML_INT_NAMEPATH_OP: /* AML_NAMESTRING_ARG */

  status = acpi_ps_get_next_namepath(walk_state,
         &(walk_state->parser_state),
         op,
         ACPI_POSSIBLE_METHOD_CALL);
  if (ACPI_FAILURE(status)) {
   return_ACPI_STATUS(status);
  }

  walk_state->arg_types = 0;
  break;

 default:
  /*
 * Op is not a constant or string, append each argument to the Op
 */
  while (GET_CURRENT_ARG_TYPE(walk_state->arg_types) &&
         !walk_state->arg_count) {
   walk_state->aml = walk_state->parser_state.aml;

   switch (op->common.aml_opcode) {
   case AML_METHOD_OP:
   case AML_BUFFER_OP:
   case AML_PACKAGE_OP:
   case AML_VARIABLE_PACKAGE_OP:
   case AML_WHILE_OP:

    break;

   default:

    ASL_CV_CAPTURE_COMMENTS(walk_state);
    break;
   }

   status =
       acpi_ps_get_next_arg(walk_state,
       &(walk_state->parser_state),
       GET_CURRENT_ARG_TYPE
       (walk_state->arg_types), &arg);
   if (ACPI_FAILURE(status)) {
    return_ACPI_STATUS(status);
   }

   if (arg) {
    acpi_ps_append_arg(op, arg);
   }

   INCREMENT_ARG_LIST(walk_state->arg_types);
  }

  ACPI_DEBUG_PRINT((ACPI_DB_PARSE,
      "Final argument count: %8.8X pass %u\n",
      walk_state->arg_count,
      walk_state->pass_number));

  /* Special processing for certain opcodes */

  switch (op->common.aml_opcode) {
  case AML_METHOD_OP:
   /*
 * Skip parsing of control method because we don't have enough
 * info in the first pass to parse it correctly.
 *
 * Save the length and address of the body
 */
   op->named.data = walk_state->parser_state.aml;
   op->named.length = (u32)
       (walk_state->parser_state.pkg_end -
        walk_state->parser_state.aml);

   /* Skip body of method */

   walk_state->parser_state.aml =
       walk_state->parser_state.pkg_end;
   walk_state->arg_count = 0;
   break;

  case AML_BUFFER_OP:
  case AML_PACKAGE_OP:
  case AML_VARIABLE_PACKAGE_OP:

   if ((op->common.parent) &&
       (op->common.parent->common.aml_opcode ==
        AML_NAME_OP)
       && (walk_state->pass_number <=
    ACPI_IMODE_LOAD_PASS2)) {
    ACPI_DEBUG_PRINT((ACPI_DB_PARSE,
        "Setup Package/Buffer: Pass %u, AML Ptr: %p\n",
        walk_state->pass_number,
        aml_op_start));

    /*
 * Skip parsing of Buffers and Packages because we don't have
 * enough info in the first pass to parse them correctly.
 */
    op->named.data = aml_op_start;
    op->named.length = (u32)
        (walk_state->parser_state.pkg_end -
         aml_op_start);

    /* Skip body */

    walk_state->parser_state.aml =
        walk_state->parser_state.pkg_end;
    walk_state->arg_count = 0;
   }
   break;

  case AML_WHILE_OP:

   if (walk_state->control_state) {
    walk_state->control_state->control.package_end =
        walk_state->parser_state.pkg_end;
   }
   break;

  default:

   /* No action for all other opcodes */

   break;
  }

  break;
 }

 return_ACPI_STATUS(AE_OK);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ps_parse_loop
 *
 * PARAMETERS:  walk_state          - Current state
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Parse AML (pointed to by the current parser state) and return
 *              a tree of ops.
 *
 ******************************************************************************/

acpi_status acpi_ps_parse_loop(struct acpi_walk_state *walk_state)
{
 acpi_status status = AE_OK;
 union acpi_parse_object *op = NULL; /* current op */
 struct acpi_parse_state *parser_state;
 u8 *aml_op_start = NULL;
 u8 opcode_length;

 ACPI_FUNCTION_TRACE_PTR(ps_parse_loop, walk_state);

 if (walk_state->descending_callback == NULL) {
  return_ACPI_STATUS(AE_BAD_PARAMETER);
 }

 parser_state = &walk_state->parser_state;
 walk_state->arg_types = 0;

#ifndef ACPI_CONSTANT_EVAL_ONLY

 if (walk_state->walk_type & ACPI_WALK_METHOD_RESTART) {

  /* We are restarting a preempted control method */

  if (acpi_ps_has_completed_scope(parser_state)) {
   /*
 * We must check if a predicate to an IF or WHILE statement
 * was just completed
 */
   if ((parser_state->scope->parse_scope.op) &&
       ((parser_state->scope->parse_scope.op->common.
         aml_opcode == AML_IF_OP)
        || (parser_state->scope->parse_scope.op->common.
     aml_opcode == AML_WHILE_OP))
       && (walk_state->control_state)
       && (walk_state->control_state->common.state ==
    ACPI_CONTROL_PREDICATE_EXECUTING)) {
    /*
 * A predicate was just completed, get the value of the
 * predicate and branch based on that value
 */
    walk_state->op = NULL;
    status =
        acpi_ds_get_predicate_value(walk_state,
        ACPI_TO_POINTER
        (TRUE));
    if (ACPI_FAILURE(status)
        && !ACPI_CNTL_EXCEPTION(status)) {
     if (status == AE_AML_NO_RETURN_VALUE) {
      ACPI_EXCEPTION((AE_INFO, status,
        "Invoked method did not return a value"));
     }

     ACPI_EXCEPTION((AE_INFO, status,
       "GetPredicate Failed"));
     return_ACPI_STATUS(status);
    }

    status =
        acpi_ps_next_parse_state(walk_state, op,
            status);
   }

   acpi_ps_pop_scope(parser_state, &op,
       &walk_state->arg_types,
       &walk_state->arg_count);
   ACPI_DEBUG_PRINT((ACPI_DB_PARSE,
       "Popped scope, Op=%p\n", op));
  } else if (walk_state->prev_op) {

   /* We were in the middle of an op */

   op = walk_state->prev_op;
   walk_state->arg_types = walk_state->prev_arg_types;
  }
 }
#endif

 /* Iterative parsing loop, while there is more AML to process: */

 while ((parser_state->aml < parser_state->aml_end) || (op)) {
  ASL_CV_CAPTURE_COMMENTS(walk_state);

  aml_op_start = parser_state->aml;
  if (!op) {
   status =
       acpi_ps_create_op(walk_state, aml_op_start, &op);
   if (ACPI_FAILURE(status)) {
    /*
 * ACPI_PARSE_MODULE_LEVEL means that we are loading a table by
 * executing it as a control method. However, if we encounter
 * an error while loading the table, we need to keep trying to
 * load the table rather than aborting the table load. Set the
 * status to AE_OK to proceed with the table load.
 */
    if ((walk_state->
         parse_flags & ACPI_PARSE_MODULE_LEVEL)
        && ((status == AE_ALREADY_EXISTS)
     || (status == AE_NOT_FOUND))) {
     status = AE_OK;
    }
    if (status == AE_CTRL_PARSE_CONTINUE) {
     continue;
    }

    if (status == AE_CTRL_PARSE_PENDING) {
     status = AE_OK;
    }

    if (status == AE_CTRL_TERMINATE) {
     return_ACPI_STATUS(status);
    }

    status =
        acpi_ps_complete_op(walk_state, &op,
       status);
    if (ACPI_FAILURE(status)) {
     return_ACPI_STATUS(status);
    }
    if (acpi_ns_opens_scope
        (acpi_ps_get_opcode_info
         (walk_state->opcode)->object_type)) {
     /*
 * If the scope/device op fails to parse, skip the body of
 * the scope op because the parse failure indicates that
 * the device may not exist.
 */
     ACPI_INFO(("Skipping parse of AML opcode: %s (0x%4.4X)", acpi_ps_get_opcode_name(walk_state->opcode), walk_state->opcode));

     /*
 * Determine the opcode length before skipping the opcode.
 * An opcode can be 1 byte or 2 bytes in length.
 */
     opcode_length = 1;
     if ((walk_state->opcode & 0xFF00) ==
         AML_EXTENDED_OPCODE) {
      opcode_length = 2;
     }
     walk_state->parser_state.aml =
         walk_state->aml + opcode_length;

     walk_state->parser_state.aml =
         acpi_ps_get_next_package_end
         (&walk_state->parser_state);
     walk_state->aml =
         walk_state->parser_state.aml;
    }

    continue;
   }

   acpi_ex_start_trace_opcode(op, walk_state);
  }

  /*
 * Start arg_count at zero because we don't know if there are
 * any args yet
 */
  walk_state->arg_count = 0;

  switch (op->common.aml_opcode) {
  case AML_BYTE_OP:
  case AML_WORD_OP:
  case AML_DWORD_OP:
  case AML_QWORD_OP:

   break;

  default:

   ASL_CV_CAPTURE_COMMENTS(walk_state);
   break;
  }

  /* Are there any arguments that must be processed? */

  if (walk_state->arg_types) {

   /* Get arguments */

   status =
       acpi_ps_get_arguments(walk_state, aml_op_start, op);
   if (ACPI_FAILURE(status)) {
    status =
        acpi_ps_complete_op(walk_state, &op,
       status);
    if (ACPI_FAILURE(status)) {
     return_ACPI_STATUS(status);
    }
    if ((walk_state->control_state) &&
        ((walk_state->control_state->control.
          opcode == AML_IF_OP)
         || (walk_state->control_state->control.
      opcode == AML_WHILE_OP))) {
     /*
 * If the if/while op fails to parse, we will skip parsing
 * the body of the op.
 */
     parser_state->aml =
         walk_state->control_state->control.
         aml_predicate_start + 1;
     parser_state->aml =
         acpi_ps_get_next_package_end
         (parser_state);
     walk_state->aml = parser_state->aml;

     ACPI_ERROR((AE_INFO,
          "Skipping While/If block"));
     if (*walk_state->aml == AML_ELSE_OP) {
      ACPI_ERROR((AE_INFO,
           "Skipping Else block"));
      walk_state->parser_state.aml =
          walk_state->aml + 1;
      walk_state->parser_state.aml =
          acpi_ps_get_next_package_end
          (parser_state);
      walk_state->aml =
          parser_state->aml;
     }
     ACPI_FREE(acpi_ut_pop_generic_state
        (&walk_state->control_state));
    }
    op = NULL;
    continue;
   }
  }

  /* Check for arguments that need to be processed */

  ACPI_DEBUG_PRINT((ACPI_DB_PARSE,
      "Parseloop: argument count: %8.8X\n",
      walk_state->arg_count));

  if (walk_state->arg_count) {
   /*
 * There are arguments (complex ones), push Op and
 * prepare for argument
 */
   status = acpi_ps_push_scope(parser_state, op,
          walk_state->arg_types,
          walk_state->arg_count);
   if (ACPI_FAILURE(status)) {
    status =
        acpi_ps_complete_op(walk_state, &op,
       status);
    if (ACPI_FAILURE(status)) {
     return_ACPI_STATUS(status);
    }

    continue;
   }

   op = NULL;
   continue;
  }

  /*
 * All arguments have been processed -- Op is complete,
 * prepare for next
 */
  walk_state->op_info =
      acpi_ps_get_opcode_info(op->common.aml_opcode);
  if (walk_state->op_info->flags & AML_NAMED) {
   if (op->common.aml_opcode == AML_REGION_OP ||
       op->common.aml_opcode == AML_DATA_REGION_OP) {
    /*
 * Skip parsing of control method or opregion body,
 * because we don't have enough info in the first pass
 * to parse them correctly.
 *
 * Completed parsing an op_region declaration, we now
 * know the length.
 */
    op->named.length =
        (u32) (parser_state->aml - op->named.data);
   }
  }

  if (walk_state->op_info->flags & AML_CREATE) {
   /*
 * Backup to beginning of create_XXXfield declaration (1 for
 * Opcode)
 *
 * body_length is unknown until we parse the body
 */
   op->named.length =
       (u32) (parser_state->aml - op->named.data);
  }

  if (op->common.aml_opcode == AML_BANK_FIELD_OP) {
   /*
 * Backup to beginning of bank_field declaration
 *
 * body_length is unknown until we parse the body
 */
   op->named.length =
       (u32) (parser_state->aml - op->named.data);
  }

  /* This op complete, notify the dispatcher */

  if (walk_state->ascending_callback != NULL) {
   walk_state->op = op;
   walk_state->opcode = op->common.aml_opcode;

   status = walk_state->ascending_callback(walk_state);
   status =
       acpi_ps_next_parse_state(walk_state, op, status);
   if (status == AE_CTRL_PENDING) {
    status = AE_OK;
   } else
       if ((walk_state->
     parse_flags & ACPI_PARSE_MODULE_LEVEL)
    && (ACPI_AML_EXCEPTION(status)
        || status == AE_ALREADY_EXISTS
        || status == AE_NOT_FOUND)) {
    /*
 * ACPI_PARSE_MODULE_LEVEL flag means that we
 * are currently loading a table by executing
 * it as a control method. However, if we
 * encounter an error while loading the table,
 * we need to keep trying to load the table
 * rather than aborting the table load (setting
 * the status to AE_OK continues the table
 * load). If we get a failure at this point, it
 * means that the dispatcher got an error while
 * trying to execute the Op.
 */
    status = AE_OK;
   }
  }

  status = acpi_ps_complete_op(walk_state, &op, status);
  if (ACPI_FAILURE(status)) {
   return_ACPI_STATUS(status);
  }

 }   /* while parser_state->Aml */

 status = acpi_ps_complete_final_op(walk_state, op, status);
 return_ACPI_STATUS(status);
}