1 | // SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0 |
2 | /****************************************************************************** |
3 | * |
4 | * Module Name: dscontrol - Support for execution control opcodes - |
5 | * if/else/while/return |
6 | * |
7 | * Copyright (C) 2000 - 2023, Intel Corp. |
8 | * |
9 | *****************************************************************************/ |
10 | |
11 | #include <acpi/acpi.h> |
12 | #include "accommon.h" |
13 | #include "amlcode.h" |
14 | #include "acdispat.h" |
15 | #include "acinterp.h" |
16 | #include "acdebug.h" |
17 | |
18 | #define _COMPONENT ACPI_DISPATCHER |
19 | ACPI_MODULE_NAME("dscontrol" ) |
20 | |
21 | /******************************************************************************* |
22 | * |
23 | * FUNCTION: acpi_ds_exec_begin_control_op |
24 | * |
25 | * PARAMETERS: walk_list - The list that owns the walk stack |
26 | * op - The control Op |
27 | * |
28 | * RETURN: Status |
29 | * |
30 | * DESCRIPTION: Handles all control ops encountered during control method |
31 | * execution. |
32 | * |
33 | ******************************************************************************/ |
34 | acpi_status |
35 | acpi_ds_exec_begin_control_op(struct acpi_walk_state *walk_state, |
36 | union acpi_parse_object *op) |
37 | { |
38 | acpi_status status = AE_OK; |
39 | union acpi_generic_state *control_state; |
40 | |
41 | ACPI_FUNCTION_NAME(ds_exec_begin_control_op); |
42 | |
43 | ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH, "Op=%p Opcode=%2.2X State=%p\n" , |
44 | op, op->common.aml_opcode, walk_state)); |
45 | |
46 | switch (op->common.aml_opcode) { |
47 | case AML_WHILE_OP: |
48 | /* |
49 | * If this is an additional iteration of a while loop, continue. |
50 | * There is no need to allocate a new control state. |
51 | */ |
52 | if (walk_state->control_state) { |
53 | if (walk_state->control_state->control. |
54 | aml_predicate_start == |
55 | (walk_state->parser_state.aml - 1)) { |
56 | |
57 | /* Reset the state to start-of-loop */ |
58 | |
59 | walk_state->control_state->common.state = |
60 | ACPI_CONTROL_CONDITIONAL_EXECUTING; |
61 | break; |
62 | } |
63 | } |
64 | |
65 | ACPI_FALLTHROUGH; |
66 | |
67 | case AML_IF_OP: |
68 | /* |
69 | * IF/WHILE: Create a new control state to manage these |
70 | * constructs. We need to manage these as a stack, in order |
71 | * to handle nesting. |
72 | */ |
73 | control_state = acpi_ut_create_control_state(); |
74 | if (!control_state) { |
75 | status = AE_NO_MEMORY; |
76 | break; |
77 | } |
78 | /* |
79 | * Save a pointer to the predicate for multiple executions |
80 | * of a loop |
81 | */ |
82 | control_state->control.aml_predicate_start = |
83 | walk_state->parser_state.aml - 1; |
84 | control_state->control.package_end = |
85 | walk_state->parser_state.pkg_end; |
86 | control_state->control.opcode = op->common.aml_opcode; |
87 | control_state->control.loop_timeout = acpi_os_get_timer() + |
88 | ((u64)acpi_gbl_max_loop_iterations * ACPI_100NSEC_PER_SEC); |
89 | |
90 | /* Push the control state on this walk's control stack */ |
91 | |
92 | acpi_ut_push_generic_state(list_head: &walk_state->control_state, |
93 | state: control_state); |
94 | break; |
95 | |
96 | case AML_ELSE_OP: |
97 | |
98 | /* Predicate is in the state object */ |
99 | /* If predicate is true, the IF was executed, ignore ELSE part */ |
100 | |
101 | if (walk_state->last_predicate) { |
102 | status = AE_CTRL_TRUE; |
103 | } |
104 | |
105 | break; |
106 | |
107 | case AML_RETURN_OP: |
108 | |
109 | break; |
110 | |
111 | default: |
112 | |
113 | break; |
114 | } |
115 | |
116 | return (status); |
117 | } |
118 | |
119 | /******************************************************************************* |
120 | * |
121 | * FUNCTION: acpi_ds_exec_end_control_op |
122 | * |
123 | * PARAMETERS: walk_list - The list that owns the walk stack |
124 | * op - The control Op |
125 | * |
126 | * RETURN: Status |
127 | * |
128 | * DESCRIPTION: Handles all control ops encountered during control method |
129 | * execution. |
130 | * |
131 | ******************************************************************************/ |
132 | |
133 | acpi_status |
134 | acpi_ds_exec_end_control_op(struct acpi_walk_state *walk_state, |
135 | union acpi_parse_object *op) |
136 | { |
137 | acpi_status status = AE_OK; |
138 | union acpi_generic_state *control_state; |
139 | |
140 | ACPI_FUNCTION_NAME(ds_exec_end_control_op); |
141 | |
142 | switch (op->common.aml_opcode) { |
143 | case AML_IF_OP: |
144 | |
145 | ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH, "[IF_OP] Op=%p\n" , op)); |
146 | |
147 | /* |
148 | * Save the result of the predicate in case there is an |
149 | * ELSE to come |
150 | */ |
151 | walk_state->last_predicate = |
152 | (u8)walk_state->control_state->common.value; |
153 | |
154 | /* |
155 | * Pop the control state that was created at the start |
156 | * of the IF and free it |
157 | */ |
158 | control_state = |
159 | acpi_ut_pop_generic_state(list_head: &walk_state->control_state); |
160 | acpi_ut_delete_generic_state(state: control_state); |
161 | break; |
162 | |
163 | case AML_ELSE_OP: |
164 | |
165 | break; |
166 | |
167 | case AML_WHILE_OP: |
168 | |
169 | ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH, "[WHILE_OP] Op=%p\n" , op)); |
170 | |
171 | control_state = walk_state->control_state; |
172 | if (control_state->common.value) { |
173 | |
174 | /* Predicate was true, the body of the loop was just executed */ |
175 | |
176 | /* |
177 | * This infinite loop detection mechanism allows the interpreter |
178 | * to escape possibly infinite loops. This can occur in poorly |
179 | * written AML when the hardware does not respond within a while |
180 | * loop and the loop does not implement a timeout. |
181 | */ |
182 | if (ACPI_TIME_AFTER(acpi_os_get_timer(), |
183 | control_state->control. |
184 | loop_timeout)) { |
185 | status = AE_AML_LOOP_TIMEOUT; |
186 | break; |
187 | } |
188 | |
189 | /* |
190 | * Go back and evaluate the predicate and maybe execute the loop |
191 | * another time |
192 | */ |
193 | status = AE_CTRL_PENDING; |
194 | walk_state->aml_last_while = |
195 | control_state->control.aml_predicate_start; |
196 | break; |
197 | } |
198 | |
199 | /* Predicate was false, terminate this while loop */ |
200 | |
201 | ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH, |
202 | "[WHILE_OP] termination! Op=%p\n" , op)); |
203 | |
204 | /* Pop this control state and free it */ |
205 | |
206 | control_state = |
207 | acpi_ut_pop_generic_state(list_head: &walk_state->control_state); |
208 | acpi_ut_delete_generic_state(state: control_state); |
209 | break; |
210 | |
211 | case AML_RETURN_OP: |
212 | |
213 | ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH, |
214 | "[RETURN_OP] Op=%p Arg=%p\n" , op, |
215 | op->common.value.arg)); |
216 | |
217 | /* |
218 | * One optional operand -- the return value |
219 | * It can be either an immediate operand or a result that |
220 | * has been bubbled up the tree |
221 | */ |
222 | if (op->common.value.arg) { |
223 | |
224 | /* Since we have a real Return(), delete any implicit return */ |
225 | |
226 | acpi_ds_clear_implicit_return(walk_state); |
227 | |
228 | /* Return statement has an immediate operand */ |
229 | |
230 | status = |
231 | acpi_ds_create_operands(walk_state, |
232 | first_arg: op->common.value.arg); |
233 | if (ACPI_FAILURE(status)) { |
234 | return (status); |
235 | } |
236 | |
237 | /* |
238 | * If value being returned is a Reference (such as |
239 | * an arg or local), resolve it now because it may |
240 | * cease to exist at the end of the method. |
241 | */ |
242 | status = |
243 | acpi_ex_resolve_to_value(stack_ptr: &walk_state->operands[0], |
244 | walk_state); |
245 | if (ACPI_FAILURE(status)) { |
246 | return (status); |
247 | } |
248 | |
249 | /* |
250 | * Get the return value and save as the last result |
251 | * value. This is the only place where walk_state->return_desc |
252 | * is set to anything other than zero! |
253 | */ |
254 | walk_state->return_desc = walk_state->operands[0]; |
255 | } else if (walk_state->result_count) { |
256 | |
257 | /* Since we have a real Return(), delete any implicit return */ |
258 | |
259 | acpi_ds_clear_implicit_return(walk_state); |
260 | |
261 | /* |
262 | * The return value has come from a previous calculation. |
263 | * |
264 | * If value being returned is a Reference (such as |
265 | * an arg or local), resolve it now because it may |
266 | * cease to exist at the end of the method. |
267 | * |
268 | * Allow references created by the Index operator to return |
269 | * unchanged. |
270 | */ |
271 | if ((ACPI_GET_DESCRIPTOR_TYPE |
272 | (walk_state->results->results.obj_desc[0]) == |
273 | ACPI_DESC_TYPE_OPERAND) |
274 | && ((walk_state->results->results.obj_desc[0])-> |
275 | common.type == ACPI_TYPE_LOCAL_REFERENCE) |
276 | && ((walk_state->results->results.obj_desc[0])-> |
277 | reference.class != ACPI_REFCLASS_INDEX)) { |
278 | status = |
279 | acpi_ex_resolve_to_value(stack_ptr: &walk_state-> |
280 | results->results. |
281 | obj_desc[0], |
282 | walk_state); |
283 | if (ACPI_FAILURE(status)) { |
284 | return (status); |
285 | } |
286 | } |
287 | |
288 | walk_state->return_desc = |
289 | walk_state->results->results.obj_desc[0]; |
290 | } else { |
291 | /* No return operand */ |
292 | |
293 | if (walk_state->num_operands) { |
294 | acpi_ut_remove_reference(object: walk_state-> |
295 | operands[0]); |
296 | } |
297 | |
298 | walk_state->operands[0] = NULL; |
299 | walk_state->num_operands = 0; |
300 | walk_state->return_desc = NULL; |
301 | } |
302 | |
303 | ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH, |
304 | "Completed RETURN_OP State=%p, RetVal=%p\n" , |
305 | walk_state, walk_state->return_desc)); |
306 | |
307 | /* End the control method execution right now */ |
308 | |
309 | status = AE_CTRL_TERMINATE; |
310 | break; |
311 | |
312 | case AML_NOOP_OP: |
313 | |
314 | /* Just do nothing! */ |
315 | |
316 | break; |
317 | |
318 | case AML_BREAKPOINT_OP: |
319 | |
320 | acpi_db_signal_break_point(walk_state); |
321 | |
322 | /* Call to the OSL in case OS wants a piece of the action */ |
323 | |
324 | status = acpi_os_signal(ACPI_SIGNAL_BREAKPOINT, |
325 | info: "Executed AML Breakpoint opcode" ); |
326 | break; |
327 | |
328 | case AML_BREAK_OP: |
329 | case AML_CONTINUE_OP: /* ACPI 2.0 */ |
330 | |
331 | /* Pop and delete control states until we find a while */ |
332 | |
333 | while (walk_state->control_state && |
334 | (walk_state->control_state->control.opcode != |
335 | AML_WHILE_OP)) { |
336 | control_state = |
337 | acpi_ut_pop_generic_state(list_head: &walk_state-> |
338 | control_state); |
339 | acpi_ut_delete_generic_state(state: control_state); |
340 | } |
341 | |
342 | /* No while found? */ |
343 | |
344 | if (!walk_state->control_state) { |
345 | return (AE_AML_NO_WHILE); |
346 | } |
347 | |
348 | /* Was: walk_state->aml_last_while = walk_state->control_state->Control.aml_predicate_start; */ |
349 | |
350 | walk_state->aml_last_while = |
351 | walk_state->control_state->control.package_end; |
352 | |
353 | /* Return status depending on opcode */ |
354 | |
355 | if (op->common.aml_opcode == AML_BREAK_OP) { |
356 | status = AE_CTRL_BREAK; |
357 | } else { |
358 | status = AE_CTRL_CONTINUE; |
359 | } |
360 | break; |
361 | |
362 | default: |
363 | |
364 | ACPI_ERROR((AE_INFO, "Unknown control opcode=0x%X Op=%p" , |
365 | op->common.aml_opcode, op)); |
366 | |
367 | status = AE_AML_BAD_OPCODE; |
368 | break; |
369 | } |
370 | |
371 | return (status); |
372 | } |
373 | |