2 MM Driver Dispatcher Dependency Evaluator
4 This routine evaluates a dependency expression (DEPENDENCY_EXPRESSION) to determine
5 if a driver can be scheduled for execution. The criteria for
6 schedulability is that the dependency expression is satisfied.
8 Copyright (c) 2009 - 2010, Intel Corporation. All rights reserved.<BR>
9 Copyright (c) 2016 - 2018, ARM Limited. All rights reserved.<BR>
10 This program and the accompanying materials are licensed and made available
11 under the terms and conditions of the BSD License which accompanies this
12 distribution. The full text of the license may be found at
13 http://opensource.org/licenses/bsd-license.php
15 THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
16 WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
20 #include "StandaloneMmCore.h"
23 /// EFI_DEP_REPLACE_TRUE - Used to dynamically patch the dependency expression
24 /// to save time. A EFI_DEP_PUSH is evaluated one an
25 /// replaced with EFI_DEP_REPLACE_TRUE. If PI spec's Vol 2
26 /// Driver Execution Environment Core Interface use 0xff
27 /// as new DEPEX opcode. EFI_DEP_REPLACE_TRUE should be
28 /// defined to a new value that is not conflicting with PI spec.
30 #define EFI_DEP_REPLACE_TRUE 0xff
33 /// Define the initial size of the dependency expression evaluation stack
35 #define DEPEX_STACK_SIZE_INCREMENT 0x1000
38 // Global stack used to evaluate dependency expressions
40 BOOLEAN
*mDepexEvaluationStack
= NULL
;
41 BOOLEAN
*mDepexEvaluationStackEnd
= NULL
;
42 BOOLEAN
*mDepexEvaluationStackPointer
= NULL
;
45 Grow size of the Depex stack
47 @retval EFI_SUCCESS Stack successfully growed.
48 @retval EFI_OUT_OF_RESOURCES There is not enough system memory to grow the stack.
59 Size
= DEPEX_STACK_SIZE_INCREMENT
;
60 if (mDepexEvaluationStack
!= NULL
) {
61 Size
= Size
+ (mDepexEvaluationStackEnd
- mDepexEvaluationStack
);
64 NewStack
= AllocatePool (Size
* sizeof (BOOLEAN
));
65 if (NewStack
== NULL
) {
66 return EFI_OUT_OF_RESOURCES
;
69 if (mDepexEvaluationStack
!= NULL
) {
71 // Copy to Old Stack to the New Stack
75 mDepexEvaluationStack
,
76 (mDepexEvaluationStackEnd
- mDepexEvaluationStack
) * sizeof (BOOLEAN
)
82 FreePool (mDepexEvaluationStack
);
86 // Make the Stack pointer point to the old data in the new stack
88 mDepexEvaluationStackPointer
= NewStack
+ (mDepexEvaluationStackPointer
- mDepexEvaluationStack
);
89 mDepexEvaluationStack
= NewStack
;
90 mDepexEvaluationStackEnd
= NewStack
+ Size
;
96 Push an element onto the Boolean Stack.
98 @param Value BOOLEAN to push.
100 @retval EFI_SUCCESS The value was pushed onto the stack.
101 @retval EFI_OUT_OF_RESOURCES There is not enough system memory to grow the stack.
112 // Check for a stack overflow condition
114 if (mDepexEvaluationStackPointer
== mDepexEvaluationStackEnd
) {
118 Status
= GrowDepexStack ();
119 if (EFI_ERROR (Status
)) {
125 // Push the item onto the stack
127 *mDepexEvaluationStackPointer
= Value
;
128 mDepexEvaluationStackPointer
++;
134 Pop an element from the Boolean stack.
136 @param Value BOOLEAN to pop.
138 @retval EFI_SUCCESS The value was popped onto the stack.
139 @retval EFI_ACCESS_DENIED The pop operation underflowed the stack.
148 // Check for a stack underflow condition
150 if (mDepexEvaluationStackPointer
== mDepexEvaluationStack
) {
151 return EFI_ACCESS_DENIED
;
155 // Pop the item off the stack
157 mDepexEvaluationStackPointer
--;
158 *Value
= *mDepexEvaluationStackPointer
;
163 This is the POSTFIX version of the dependency evaluator. This code does
164 not need to handle Before or After, as it is not valid to call this
165 routine in this case. POSTFIX means all the math is done on top of the stack.
167 @param DriverEntry DriverEntry element to update.
169 @retval TRUE If driver is ready to run.
170 @retval FALSE If driver is not ready to run or some fatal error
176 IN EFI_MM_DRIVER_ENTRY
*DriverEntry
189 if (DriverEntry
->After
|| DriverEntry
->Before
) {
191 // If Before or After Depex skip as MmInsertOnScheduledQueueWhileProcessingBeforeAndAfter ()
197 DEBUG ((DEBUG_DISPATCH
, "Evaluate MM DEPEX for FFS(%g)\n", &DriverEntry
->FileName
));
199 if (DriverEntry
->Depex
== NULL
) {
201 // A NULL Depex means that the MM driver is not built correctly.
202 // All MM drivers must have a valid depex expressiion.
204 DEBUG ((DEBUG_DISPATCH
, " RESULT = FALSE (Depex is empty)\n"));
210 // Clean out memory leaks in Depex Boolean stack. Leaks are only caused by
211 // incorrectly formed DEPEX expressions
213 mDepexEvaluationStackPointer
= mDepexEvaluationStack
;
216 Iterator
= DriverEntry
->Depex
;
220 // Check to see if we are attempting to fetch dependency expression instructions
221 // past the end of the dependency expression.
223 if (((UINTN
)Iterator
- (UINTN
)DriverEntry
->Depex
) >= DriverEntry
->DepexSize
) {
224 DEBUG ((DEBUG_DISPATCH
, " RESULT = FALSE (Attempt to fetch past end of depex)\n"));
229 // Look at the opcode of the dependency expression instruction.
235 // For a well-formed Dependency Expression, the code should never get here.
236 // The BEFORE and AFTER are processed prior to this routine's invocation.
237 // If the code flow arrives at this point, there was a BEFORE or AFTER
238 // that were not the first opcodes.
240 DEBUG ((DEBUG_DISPATCH
, " RESULT = FALSE (Unexpected BEFORE or AFTER opcode)\n"));
245 // Push operator is followed by a GUID. Test to see if the GUID protocol
246 // is installed and push the boolean result on the stack.
248 CopyMem (&DriverGuid
, Iterator
+ 1, sizeof (EFI_GUID
));
250 Status
= MmLocateProtocol (&DriverGuid
, NULL
, &Interface
);
251 if (EFI_ERROR (Status
) && (mEfiSystemTable
!= NULL
)) {
253 // For MM Driver, it may depend on uefi protocols
255 Status
= mEfiSystemTable
->BootServices
->LocateProtocol (&DriverGuid
, NULL
, &Interface
);
258 if (EFI_ERROR (Status
)) {
259 DEBUG ((DEBUG_DISPATCH
, " PUSH GUID(%g) = FALSE\n", &DriverGuid
));
260 Status
= PushBool (FALSE
);
262 DEBUG ((DEBUG_DISPATCH
, " PUSH GUID(%g) = TRUE\n", &DriverGuid
));
263 *Iterator
= EFI_DEP_REPLACE_TRUE
;
264 Status
= PushBool (TRUE
);
266 if (EFI_ERROR (Status
)) {
267 DEBUG ((DEBUG_DISPATCH
, " RESULT = FALSE (Unexpected error)\n"));
271 Iterator
+= sizeof (EFI_GUID
);
275 DEBUG ((DEBUG_DISPATCH
, " AND\n"));
276 Status
= PopBool (&Operator
);
277 if (EFI_ERROR (Status
)) {
278 DEBUG ((DEBUG_DISPATCH
, " RESULT = FALSE (Unexpected error)\n"));
282 Status
= PopBool (&Operator2
);
283 if (EFI_ERROR (Status
)) {
284 DEBUG ((DEBUG_DISPATCH
, " RESULT = FALSE (Unexpected error)\n"));
288 Status
= PushBool ((BOOLEAN
)(Operator
&& Operator2
));
289 if (EFI_ERROR (Status
)) {
290 DEBUG ((DEBUG_DISPATCH
, " RESULT = FALSE (Unexpected error)\n"));
296 DEBUG ((DEBUG_DISPATCH
, " OR\n"));
297 Status
= PopBool (&Operator
);
298 if (EFI_ERROR (Status
)) {
299 DEBUG ((DEBUG_DISPATCH
, " RESULT = FALSE (Unexpected error)\n"));
303 Status
= PopBool (&Operator2
);
304 if (EFI_ERROR (Status
)) {
305 DEBUG ((DEBUG_DISPATCH
, " RESULT = FALSE (Unexpected error)\n"));
309 Status
= PushBool ((BOOLEAN
)(Operator
|| Operator2
));
310 if (EFI_ERROR (Status
)) {
311 DEBUG ((DEBUG_DISPATCH
, " RESULT = FALSE (Unexpected error)\n"));
317 DEBUG ((DEBUG_DISPATCH
, " NOT\n"));
318 Status
= PopBool (&Operator
);
319 if (EFI_ERROR (Status
)) {
320 DEBUG ((DEBUG_DISPATCH
, " RESULT = FALSE (Unexpected error)\n"));
324 Status
= PushBool ((BOOLEAN
)(!Operator
));
325 if (EFI_ERROR (Status
)) {
326 DEBUG ((DEBUG_DISPATCH
, " RESULT = FALSE (Unexpected error)\n"));
332 DEBUG ((DEBUG_DISPATCH
, " TRUE\n"));
333 Status
= PushBool (TRUE
);
334 if (EFI_ERROR (Status
)) {
335 DEBUG ((DEBUG_DISPATCH
, " RESULT = FALSE (Unexpected error)\n"));
341 DEBUG ((DEBUG_DISPATCH
, " FALSE\n"));
342 Status
= PushBool (FALSE
);
343 if (EFI_ERROR (Status
)) {
344 DEBUG ((DEBUG_DISPATCH
, " RESULT = FALSE (Unexpected error)\n"));
350 DEBUG ((DEBUG_DISPATCH
, " END\n"));
351 Status
= PopBool (&Operator
);
352 if (EFI_ERROR (Status
)) {
353 DEBUG ((DEBUG_DISPATCH
, " RESULT = FALSE (Unexpected error)\n"));
356 DEBUG ((DEBUG_DISPATCH
, " RESULT = %a\n", Operator
? "TRUE" : "FALSE"));
359 case EFI_DEP_REPLACE_TRUE
:
360 CopyMem (&DriverGuid
, Iterator
+ 1, sizeof (EFI_GUID
));
361 DEBUG ((DEBUG_DISPATCH
, " PUSH GUID(%g) = TRUE\n", &DriverGuid
));
362 Status
= PushBool (TRUE
);
363 if (EFI_ERROR (Status
)) {
364 DEBUG ((DEBUG_DISPATCH
, " RESULT = FALSE (Unexpected error)\n"));
368 Iterator
+= sizeof (EFI_GUID
);
372 DEBUG ((DEBUG_DISPATCH
, " RESULT = FALSE (Unknown opcode)\n"));
377 // Skip over the Dependency Op Code we just processed in the switch.
378 // The math is done out of order, but it should not matter. That is
379 // we may add in the sizeof (EFI_GUID) before we account for the OP Code.
380 // This is not an issue, since we just need the correct end result. You
381 // need to be careful using Iterator in the loop as it's intermediate value