1// SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0
2/******************************************************************************
3 *
4 * Module Name: psloop - Main AML parse loop
5 *
6 * Copyright (C) 2000 - 2020, Intel Corp.
7 *
8 *****************************************************************************/
9
10/*
11 * Parse the AML and build an operation tree as most interpreters, (such as
12 * Perl) do. Parsing is done by hand rather than with a YACC generated parser
13 * to tightly constrain stack and dynamic memory usage. Parsing is kept
14 * flexible and the code fairly compact by parsing based on a list of AML
15 * opcode templates in aml_op_info[].
16 */
17
18#include <acpi/acpi.h>
19#include "accommon.h"
20#include "acinterp.h"
21#include "acparser.h"
22#include "acdispat.h"
23#include "amlcode.h"
24#include "acconvert.h"
25#include "acnamesp.h"
26
27#define _COMPONENT          ACPI_PARSER
28ACPI_MODULE_NAME("psloop")
29
30/* Local prototypes */
31static acpi_status
32acpi_ps_get_arguments(struct acpi_walk_state *walk_state,
33		      u8 * aml_op_start, union acpi_parse_object *op);
34
35/*******************************************************************************
36 *
37 * FUNCTION:    acpi_ps_get_arguments
38 *
39 * PARAMETERS:  walk_state          - Current state
40 *              aml_op_start        - Op start in AML
41 *              op                  - Current Op
42 *
43 * RETURN:      Status
44 *
45 * DESCRIPTION: Get arguments for passed Op.
46 *
47 ******************************************************************************/
48
49static acpi_status
50acpi_ps_get_arguments(struct acpi_walk_state *walk_state,
51		      u8 * aml_op_start, union acpi_parse_object *op)
52{
53	acpi_status status = AE_OK;
54	union acpi_parse_object *arg = NULL;
55
56	ACPI_FUNCTION_TRACE_PTR(ps_get_arguments, walk_state);
57
58	ACPI_DEBUG_PRINT((ACPI_DB_PARSE,
59			  "Get arguments for opcode [%s]\n",
60			  op->common.aml_op_name));
61
62	switch (op->common.aml_opcode) {
63	case AML_BYTE_OP:	/* AML_BYTEDATA_ARG */
64	case AML_WORD_OP:	/* AML_WORDDATA_ARG */
65	case AML_DWORD_OP:	/* AML_DWORDATA_ARG */
66	case AML_QWORD_OP:	/* AML_QWORDATA_ARG */
67	case AML_STRING_OP:	/* AML_ASCIICHARLIST_ARG */
68
69		/* Fill in constant or string argument directly */
70
71		acpi_ps_get_next_simple_arg(&(walk_state->parser_state),
72					    GET_CURRENT_ARG_TYPE(walk_state->
73								 arg_types),
74					    op);
75		break;
76
77	case AML_INT_NAMEPATH_OP:	/* AML_NAMESTRING_ARG */
78
79		status = acpi_ps_get_next_namepath(walk_state,
80						   &(walk_state->parser_state),
81						   op,
82						   ACPI_POSSIBLE_METHOD_CALL);
83		if (ACPI_FAILURE(status)) {
84			return_ACPI_STATUS(status);
85		}
86
87		walk_state->arg_types = 0;
88		break;
89
90	default:
91		/*
92		 * Op is not a constant or string, append each argument to the Op
93		 */
94		while (GET_CURRENT_ARG_TYPE(walk_state->arg_types) &&
95		       !walk_state->arg_count) {
96			walk_state->aml = walk_state->parser_state.aml;
97
98			switch (op->common.aml_opcode) {
99			case AML_METHOD_OP:
100			case AML_BUFFER_OP:
101			case AML_PACKAGE_OP:
102			case AML_VARIABLE_PACKAGE_OP:
103			case AML_WHILE_OP:
104
105				break;
106
107			default:
108
109				ASL_CV_CAPTURE_COMMENTS(walk_state);
110				break;
111			}
112
113			status =
114			    acpi_ps_get_next_arg(walk_state,
115						 &(walk_state->parser_state),
116						 GET_CURRENT_ARG_TYPE
117						 (walk_state->arg_types), &arg);
118			if (ACPI_FAILURE(status)) {
119				return_ACPI_STATUS(status);
120			}
121
122			if (arg) {
123				acpi_ps_append_arg(op, arg);
124			}
125
126			INCREMENT_ARG_LIST(walk_state->arg_types);
127		}
128
129		ACPI_DEBUG_PRINT((ACPI_DB_PARSE,
130				  "Final argument count: %8.8X pass %u\n",
131				  walk_state->arg_count,
132				  walk_state->pass_number));
133
134		/* Special processing for certain opcodes */
135
136		switch (op->common.aml_opcode) {
137		case AML_METHOD_OP:
138			/*
139			 * Skip parsing of control method because we don't have enough
140			 * info in the first pass to parse it correctly.
141			 *
142			 * Save the length and address of the body
143			 */
144			op->named.data = walk_state->parser_state.aml;
145			op->named.length = (u32)
146			    (walk_state->parser_state.pkg_end -
147			     walk_state->parser_state.aml);
148
149			/* Skip body of method */
150
151			walk_state->parser_state.aml =
152			    walk_state->parser_state.pkg_end;
153			walk_state->arg_count = 0;
154			break;
155
156		case AML_BUFFER_OP:
157		case AML_PACKAGE_OP:
158		case AML_VARIABLE_PACKAGE_OP:
159
160			if ((op->common.parent) &&
161			    (op->common.parent->common.aml_opcode ==
162			     AML_NAME_OP)
163			    && (walk_state->pass_number <=
164				ACPI_IMODE_LOAD_PASS2)) {
165				ACPI_DEBUG_PRINT((ACPI_DB_PARSE,
166						  "Setup Package/Buffer: Pass %u, AML Ptr: %p\n",
167						  walk_state->pass_number,
168						  aml_op_start));
169
170				/*
171				 * Skip parsing of Buffers and Packages because we don't have
172				 * enough info in the first pass to parse them correctly.
173				 */
174				op->named.data = aml_op_start;
175				op->named.length = (u32)
176				    (walk_state->parser_state.pkg_end -
177				     aml_op_start);
178
179				/* Skip body */
180
181				walk_state->parser_state.aml =
182				    walk_state->parser_state.pkg_end;
183				walk_state->arg_count = 0;
184			}
185			break;
186
187		case AML_WHILE_OP:
188
189			if (walk_state->control_state) {
190				walk_state->control_state->control.package_end =
191				    walk_state->parser_state.pkg_end;
192			}
193			break;
194
195		default:
196
197			/* No action for all other opcodes */
198
199			break;
200		}
201
202		break;
203	}
204
205	return_ACPI_STATUS(AE_OK);
206}
207
208/*******************************************************************************
209 *
210 * FUNCTION:    acpi_ps_parse_loop
211 *
212 * PARAMETERS:  walk_state          - Current state
213 *
214 * RETURN:      Status
215 *
216 * DESCRIPTION: Parse AML (pointed to by the current parser state) and return
217 *              a tree of ops.
218 *
219 ******************************************************************************/
220
221acpi_status acpi_ps_parse_loop(struct acpi_walk_state *walk_state)
222{
223	acpi_status status = AE_OK;
224	union acpi_parse_object *op = NULL;	/* current op */
225	struct acpi_parse_state *parser_state;
226	u8 *aml_op_start = NULL;
227	u8 opcode_length;
228
229	ACPI_FUNCTION_TRACE_PTR(ps_parse_loop, walk_state);
230
231	if (walk_state->descending_callback == NULL) {
232		return_ACPI_STATUS(AE_BAD_PARAMETER);
233	}
234
235	parser_state = &walk_state->parser_state;
236	walk_state->arg_types = 0;
237
238#ifndef ACPI_CONSTANT_EVAL_ONLY
239
240	if (walk_state->walk_type & ACPI_WALK_METHOD_RESTART) {
241
242		/* We are restarting a preempted control method */
243
244		if (acpi_ps_has_completed_scope(parser_state)) {
245			/*
246			 * We must check if a predicate to an IF or WHILE statement
247			 * was just completed
248			 */
249			if ((parser_state->scope->parse_scope.op) &&
250			    ((parser_state->scope->parse_scope.op->common.
251			      aml_opcode == AML_IF_OP)
252			     || (parser_state->scope->parse_scope.op->common.
253				 aml_opcode == AML_WHILE_OP))
254			    && (walk_state->control_state)
255			    && (walk_state->control_state->common.state ==
256				ACPI_CONTROL_PREDICATE_EXECUTING)) {
257				/*
258				 * A predicate was just completed, get the value of the
259				 * predicate and branch based on that value
260				 */
261				walk_state->op = NULL;
262				status =
263				    acpi_ds_get_predicate_value(walk_state,
264								ACPI_TO_POINTER
265								(TRUE));
266				if (ACPI_FAILURE(status)
267				    && ((status & AE_CODE_MASK) !=
268					AE_CODE_CONTROL)) {
269					if (status == AE_AML_NO_RETURN_VALUE) {
270						ACPI_EXCEPTION((AE_INFO, status,
271								"Invoked method did not return a value"));
272					}
273
274					ACPI_EXCEPTION((AE_INFO, status,
275							"GetPredicate Failed"));
276					return_ACPI_STATUS(status);
277				}
278
279				status =
280				    acpi_ps_next_parse_state(walk_state, op,
281							     status);
282			}
283
284			acpi_ps_pop_scope(parser_state, &op,
285					  &walk_state->arg_types,
286					  &walk_state->arg_count);
287			ACPI_DEBUG_PRINT((ACPI_DB_PARSE,
288					  "Popped scope, Op=%p\n", op));
289		} else if (walk_state->prev_op) {
290
291			/* We were in the middle of an op */
292
293			op = walk_state->prev_op;
294			walk_state->arg_types = walk_state->prev_arg_types;
295		}
296	}
297#endif
298
299	/* Iterative parsing loop, while there is more AML to process: */
300
301	while ((parser_state->aml < parser_state->aml_end) || (op)) {
302		ASL_CV_CAPTURE_COMMENTS(walk_state);
303
304		aml_op_start = parser_state->aml;
305		if (!op) {
306			status =
307			    acpi_ps_create_op(walk_state, aml_op_start, &op);
308			if (ACPI_FAILURE(status)) {
309				/*
310				 * ACPI_PARSE_MODULE_LEVEL means that we are loading a table by
311				 * executing it as a control method. However, if we encounter
312				 * an error while loading the table, we need to keep trying to
313				 * load the table rather than aborting the table load. Set the
314				 * status to AE_OK to proceed with the table load.
315				 */
316				if ((walk_state->
317				     parse_flags & ACPI_PARSE_MODULE_LEVEL)
318				    && ((status == AE_ALREADY_EXISTS)
319					|| (status == AE_NOT_FOUND))) {
320					status = AE_OK;
321				}
322				if (status == AE_CTRL_PARSE_CONTINUE) {
323					continue;
324				}
325
326				if (status == AE_CTRL_PARSE_PENDING) {
327					status = AE_OK;
328				}
329
330				if (status == AE_CTRL_TERMINATE) {
331					return_ACPI_STATUS(status);
332				}
333
334				status =
335				    acpi_ps_complete_op(walk_state, &op,
336							status);
337				if (ACPI_FAILURE(status)) {
338					return_ACPI_STATUS(status);
339				}
340				if (acpi_ns_opens_scope
341				    (acpi_ps_get_opcode_info
342				     (walk_state->opcode)->object_type)) {
343					/*
344					 * If the scope/device op fails to parse, skip the body of
345					 * the scope op because the parse failure indicates that
346					 * the device may not exist.
347					 */
348					ACPI_INFO(("Skipping parse of AML opcode: %s (0x%4.4X)", acpi_ps_get_opcode_name(walk_state->opcode), walk_state->opcode));
349
350					/*
351					 * Determine the opcode length before skipping the opcode.
352					 * An opcode can be 1 byte or 2 bytes in length.
353					 */
354					opcode_length = 1;
355					if ((walk_state->opcode & 0xFF00) ==
356					    AML_EXTENDED_OPCODE) {
357						opcode_length = 2;
358					}
359					walk_state->parser_state.aml =
360					    walk_state->aml + opcode_length;
361
362					walk_state->parser_state.aml =
363					    acpi_ps_get_next_package_end
364					    (&walk_state->parser_state);
365					walk_state->aml =
366					    walk_state->parser_state.aml;
367				}
368
369				continue;
370			}
371
372			acpi_ex_start_trace_opcode(op, walk_state);
373		}
374
375		/*
376		 * Start arg_count at zero because we don't know if there are
377		 * any args yet
378		 */
379		walk_state->arg_count = 0;
380
381		switch (op->common.aml_opcode) {
382		case AML_BYTE_OP:
383		case AML_WORD_OP:
384		case AML_DWORD_OP:
385		case AML_QWORD_OP:
386
387			break;
388
389		default:
390
391			ASL_CV_CAPTURE_COMMENTS(walk_state);
392			break;
393		}
394
395		/* Are there any arguments that must be processed? */
396
397		if (walk_state->arg_types) {
398
399			/* Get arguments */
400
401			status =
402			    acpi_ps_get_arguments(walk_state, aml_op_start, op);
403			if (ACPI_FAILURE(status)) {
404				status =
405				    acpi_ps_complete_op(walk_state, &op,
406							status);
407				if (ACPI_FAILURE(status)) {
408					return_ACPI_STATUS(status);
409				}
410				if ((walk_state->control_state) &&
411				    ((walk_state->control_state->control.
412				      opcode == AML_IF_OP)
413				     || (walk_state->control_state->control.
414					 opcode == AML_WHILE_OP))) {
415					/*
416					 * If the if/while op fails to parse, we will skip parsing
417					 * the body of the op.
418					 */
419					parser_state->aml =
420					    walk_state->control_state->control.
421					    aml_predicate_start + 1;
422					parser_state->aml =
423					    acpi_ps_get_next_package_end
424					    (parser_state);
425					walk_state->aml = parser_state->aml;
426
427					ACPI_ERROR((AE_INFO,
428						    "Skipping While/If block"));
429					if (*walk_state->aml == AML_ELSE_OP) {
430						ACPI_ERROR((AE_INFO,
431							    "Skipping Else block"));
432						walk_state->parser_state.aml =
433						    walk_state->aml + 1;
434						walk_state->parser_state.aml =
435						    acpi_ps_get_next_package_end
436						    (parser_state);
437						walk_state->aml =
438						    parser_state->aml;
439					}
440					ACPI_FREE(acpi_ut_pop_generic_state
441						  (&walk_state->control_state));
442				}
443				op = NULL;
444				continue;
445			}
446		}
447
448		/* Check for arguments that need to be processed */
449
450		ACPI_DEBUG_PRINT((ACPI_DB_PARSE,
451				  "Parseloop: argument count: %8.8X\n",
452				  walk_state->arg_count));
453
454		if (walk_state->arg_count) {
455			/*
456			 * There are arguments (complex ones), push Op and
457			 * prepare for argument
458			 */
459			status = acpi_ps_push_scope(parser_state, op,
460						    walk_state->arg_types,
461						    walk_state->arg_count);
462			if (ACPI_FAILURE(status)) {
463				status =
464				    acpi_ps_complete_op(walk_state, &op,
465							status);
466				if (ACPI_FAILURE(status)) {
467					return_ACPI_STATUS(status);
468				}
469
470				continue;
471			}
472
473			op = NULL;
474			continue;
475		}
476
477		/*
478		 * All arguments have been processed -- Op is complete,
479		 * prepare for next
480		 */
481		walk_state->op_info =
482		    acpi_ps_get_opcode_info(op->common.aml_opcode);
483		if (walk_state->op_info->flags & AML_NAMED) {
484			if (op->common.aml_opcode == AML_REGION_OP ||
485			    op->common.aml_opcode == AML_DATA_REGION_OP) {
486				/*
487				 * Skip parsing of control method or opregion body,
488				 * because we don't have enough info in the first pass
489				 * to parse them correctly.
490				 *
491				 * Completed parsing an op_region declaration, we now
492				 * know the length.
493				 */
494				op->named.length =
495				    (u32) (parser_state->aml - op->named.data);
496			}
497		}
498
499		if (walk_state->op_info->flags & AML_CREATE) {
500			/*
501			 * Backup to beginning of create_XXXfield declaration (1 for
502			 * Opcode)
503			 *
504			 * body_length is unknown until we parse the body
505			 */
506			op->named.length =
507			    (u32) (parser_state->aml - op->named.data);
508		}
509
510		if (op->common.aml_opcode == AML_BANK_FIELD_OP) {
511			/*
512			 * Backup to beginning of bank_field declaration
513			 *
514			 * body_length is unknown until we parse the body
515			 */
516			op->named.length =
517			    (u32) (parser_state->aml - op->named.data);
518		}
519
520		/* This op complete, notify the dispatcher */
521
522		if (walk_state->ascending_callback != NULL) {
523			walk_state->op = op;
524			walk_state->opcode = op->common.aml_opcode;
525
526			status = walk_state->ascending_callback(walk_state);
527			status =
528			    acpi_ps_next_parse_state(walk_state, op, status);
529			if (status == AE_CTRL_PENDING) {
530				status = AE_OK;
531			} else
532			    if ((walk_state->
533				 parse_flags & ACPI_PARSE_MODULE_LEVEL)
534				&& (ACPI_AML_EXCEPTION(status)
535				    || status == AE_ALREADY_EXISTS
536				    || status == AE_NOT_FOUND)) {
537				/*
538				 * ACPI_PARSE_MODULE_LEVEL flag means that we
539				 * are currently loading a table by executing
540				 * it as a control method. However, if we
541				 * encounter an error while loading the table,
542				 * we need to keep trying to load the table
543				 * rather than aborting the table load (setting
544				 * the status to AE_OK continues the table
545				 * load). If we get a failure at this point, it
546				 * means that the dispatcher got an error while
547				 * trying to execute the Op.
548				 */
549				status = AE_OK;
550			}
551		}
552
553		status = acpi_ps_complete_op(walk_state, &op, status);
554		if (ACPI_FAILURE(status)) {
555			return_ACPI_STATUS(status);
556		}
557
558	}			/* while parser_state->Aml */
559
560	status = acpi_ps_complete_final_op(walk_state, op, status);
561	return_ACPI_STATUS(status);
562}
563