[mirror_edk2.git] / EdkModulePkg / Core / Pei / Dependency / dependency.c

/*++\r
\r
Copyright (c) 2006, Intel Corporation                                                         \r
All rights reserved. This program and the accompanying materials                          \r
are licensed and made available under the terms and conditions of the BSD License         \r
which accompanies this distribution.  The full text of the license may be found at        \r
http://opensource.org/licenses/bsd-license.php                                            \r
                                                                                          \r
THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,                     \r
WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.             \r
\r
Module Name:\r
\r
  dependency.c\r
\r
Abstract:\r
\r
  PEI Dispatcher Dependency Evaluator\r
\r
  This routine evaluates a dependency expression (DEPENDENCY_EXPRESSION) to determine\r
  if a driver can be scheduled for execution.  The criteria for\r
  schedulability is that the dependency expression is satisfied.\r
  \r
--*/\r
\r
#include <PeiMain.h>\r
#include "dependency.h"\r
\r
STATIC\r
BOOLEAN\r
IsPpiInstalled (\r
  IN EFI_PEI_SERVICES  **PeiServices,\r
  IN EVAL_STACK_ENTRY  *Stack\r
  )\r
/*++\r
\r
Routine Description:\r
\r
  This routine determines if a PPI has been installed.\r
  The truth value of a GUID is determined by if the PPI has\r
  been published and can be queried from the PPI database.\r
\r
Arguments:\r
  PeiServices - The PEI core services table.\r
  Stack       - Reference to EVAL_STACK_ENTRY that contains PPI GUID to check\r
\r
Returns:\r
\r
  True if the PPI is already installed.\r
  False if the PPI has yet to be installed.\r
\r
--*/\r
{\r
  VOID        *PeiInstance;\r
  EFI_STATUS  Status;\r
  EFI_GUID    PpiGuid;\r
  \r
  //\r
  // If there is no GUID to evaluate, just return current result on stack.\r
  //\r
  if (Stack->Operator == NULL) {\r
    return Stack->Result;\r
  }\r
  \r
  //\r
  // Copy the Guid into a locale variable so that there are no\r
  // possibilities of alignment faults for cross-compilation \r
  // environments such as Intel?Itanium(TM).\r
  //\r
  CopyMem(&PpiGuid, Stack->Operator, sizeof(EFI_GUID));\r
\r
  //\r
  // Check if the PPI is installed.\r
  //\r
  Status = PeiServicesLocatePpi(\r
             &PpiGuid,        // GUID\r
             0,               // INSTANCE\r
             NULL,            // EFI_PEI_PPI_DESCRIPTOR\r
             &PeiInstance     // PPI\r
             );\r
\r
  if (EFI_ERROR(Status)) {\r
    return FALSE;\r
  }\r
   \r
  return TRUE;\r
}\r
\r
\r
EFI_STATUS\r
PeimDispatchReadiness (\r
  IN EFI_PEI_SERVICES   **PeiServices,\r
  IN VOID               *DependencyExpression,\r
  OUT BOOLEAN           *Runnable\r
  )\r
/*++\r
\r
Routine Description:\r
\r
  This is the POSTFIX version of the dependency evaluator.  When a\r
  PUSH [PPI GUID] is encountered, a pointer to the GUID is stored on\r
  the evaluation stack.  When that entry is poped from the evaluation\r
  stack, the PPI is checked if it is installed.  This method allows\r
  some time savings as not all PPIs must be checked for certain\r
  operation types (AND, OR).\r
\r
Arguments:\r
\r
  PeiServices               - Calling context.\r
\r
  DependencyExpression      - Pointer to a dependency expression.  The Grammar adheres to \r
                              the BNF described above and is stored in postfix notation.\r
  Runnable                  - is True if the driver can be scheduled and False if the driver \r
                              cannot be scheduled.  This is the value that the schedulers \r
                              should use for deciding the state of the driver.\r
\r
Returns:\r
\r
  Status = EFI_SUCCESS            if it is a well-formed Grammar\r
           EFI_INVALID_PARAMETER  if the dependency expression overflows\r
                                  the evaluation stack\r
           EFI_INVALID_PARAMETER  if the dependency expression underflows\r
                                  the evaluation stack\r
           EFI_INVALID_PARAMETER  if the dependency expression is not a\r
                                  well-formed Grammar.\r
--*/\r
{\r
  EFI_STATUS                     Status;\r
  DEPENDENCY_EXPRESSION_OPERAND  *Iterator;\r
  EVAL_STACK_ENTRY               *StackPtr;\r
  EVAL_STACK_ENTRY               EvalStack[MAX_GRAMMAR_SIZE];\r
\r
  Status    = EFI_SUCCESS;\r
  Iterator  = DependencyExpression;\r
  *Runnable = FALSE;\r
\r
  StackPtr = &EvalStack[0];\r
\r
  while (TRUE) {\r
\r
    switch (*(Iterator++)) {\r
      \r
      //\r
      // For performance reason we put the frequently used items in front of \r
      // the rarely used  items\r
      //\r
      \r
      case (EFI_DEP_PUSH):\r
        //\r
        // Check to make sure the dependency grammar doesn't overflow the\r
        // EvalStack on the push\r
        //\r
        if (StackPtr > &EvalStack[MAX_GRAMMAR_SIZE-1]) {\r
          return EFI_INVALID_PARAMETER;\r
        }\r
\r
        //\r
        // Push the pointer to the PUSH opcode operator (pointer to PPI GUID)\r
        // We will evaluate if the PPI is insalled on the POP operation.\r
        //\r
        StackPtr->Operator = (VOID *) Iterator;\r
        Iterator = Iterator + sizeof (EFI_GUID);\r
        StackPtr++;\r
        break;\r
\r
      case (EFI_DEP_AND):    \r
      case (EFI_DEP_OR):     \r
        //\r
        // Check to make sure the dependency grammar doesn't underflow the\r
        // EvalStack on the two POPs for the AND operation.  Don't need to\r
        // check for the overflow on PUSHing the result since we already\r
        // did two POPs.\r
        //\r
        if (StackPtr < &EvalStack[2]) {\r
          return EFI_INVALID_PARAMETER;\r
        }\r
\r
        //\r
        // Evaluate the first POPed operator only. If the operand is\r
        // EFI_DEP_AND and the POPed operator evaluates to FALSE, or the\r
        // operand is EFI_DEP_OR and the POPed operator evaluates to TRUE,\r
        // we don't need to check the second operator, and the result will be\r
        // evaluation of the POPed operator. Otherwise, don't POP the second\r
        // operator since it will now evaluate to the final result on the\r
        // next operand that causes a POP.\r
        // \r
        StackPtr--;\r
        //\r
        // Iterator has increased by 1 after we retrieve the operand, so here we \r
        // should get the value pointed by (Iterator - 1), in order to obtain the \r
        // same operand.\r
        //\r
        if (*(Iterator - 1) == EFI_DEP_AND) {\r
          if (!(IsPpiInstalled (PeiServices, StackPtr))) {\r
            (StackPtr-1)->Result = FALSE;\r
            (StackPtr-1)->Operator = NULL;\r
          }\r
        } else {\r
          if (IsPpiInstalled (PeiServices, StackPtr)) {\r
            (StackPtr-1)->Result = TRUE;\r
            (StackPtr-1)->Operator = NULL;\r
          }\r
        }\r
        break;\r
        \r
      case (EFI_DEP_END):\r
        StackPtr--;\r
        //\r
        // Check to make sure EvalStack is balanced.  If not, then there is\r
        // an error in the dependency grammar, so return EFI_INVALID_PARAMETER.\r
        //\r
        if (StackPtr != &EvalStack[0]) {\r
          return EFI_INVALID_PARAMETER;\r
        }\r
        *Runnable = IsPpiInstalled (PeiServices, StackPtr);\r
        return EFI_SUCCESS;\r
        break;\r
\r
      case (EFI_DEP_NOT):    \r
        //\r
        // Check to make sure the dependency grammar doesn't underflow the\r
        // EvalStack on the POP for the NOT operation.  Don't need to\r
        // check for the overflow on PUSHing the result since we already\r
        // did a POP.\r
        //\r
        if (StackPtr < &EvalStack[1]) {\r
          return EFI_INVALID_PARAMETER;\r
        }\r
        (StackPtr-1)->Result = (BOOLEAN) !IsPpiInstalled (PeiServices, (StackPtr-1));\r
        (StackPtr-1)->Operator = NULL;\r
        break;\r
\r
      case (EFI_DEP_TRUE):\r
      case (EFI_DEP_FALSE):\r
        //\r
        // Check to make sure the dependency grammar doesn't overflow the\r
        // EvalStack on the push\r
        //\r
        if (StackPtr > &EvalStack[MAX_GRAMMAR_SIZE-1]) {\r
          return EFI_INVALID_PARAMETER;\r
        }\r
        //\r
        // Iterator has increased by 1 after we retrieve the operand, so here we \r
        // should get the value pointed by (Iterator - 1), in order to obtain the \r
        // same operand.\r
        //\r
        if (*(Iterator - 1) == EFI_DEP_TRUE) {\r
          StackPtr->Result = TRUE;\r
        } else {\r
          StackPtr->Result = FALSE;\r
        }\r
        StackPtr->Operator = NULL;\r
        StackPtr++;\r
        break;\r
\r
      default:\r
        //\r
        // The grammar should never arrive here\r
        //\r
        return EFI_INVALID_PARAMETER;\r
        break;\r
    }\r
  }\r
}\r
Commit	Line	Data
878ddf1f	1	/*++\r
	2	\r
	3	Copyright (c) 2006, Intel Corporation \r
	4	All rights reserved. This program and the accompanying materials \r
	5	are licensed and made available under the terms and conditions of the BSD License \r
	6	which accompanies this distribution. The full text of the license may be found at \r
	7	http://opensource.org/licenses/bsd-license.php \r
	8	\r
	9	THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, \r
	10	WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED. \r
	11	\r
	12	Module Name:\r
	13	\r
	14	dependency.c\r
	15	\r
	16	Abstract:\r
	17	\r
	18	PEI Dispatcher Dependency Evaluator\r
	19	\r
	20	This routine evaluates a dependency expression (DEPENDENCY_EXPRESSION) to determine\r
	21	if a driver can be scheduled for execution. The criteria for\r
	22	schedulability is that the dependency expression is satisfied.\r
	23	\r
	24	--*/\r
	25	\r
	26	#include <PeiMain.h>\r
4cbd855e	27	#include "dependency.h"\r
878ddf1f	28	\r
	29	STATIC\r
	30	BOOLEAN\r
	31	IsPpiInstalled (\r
	32	IN EFI_PEI_SERVICES **PeiServices,\r
	33	IN EVAL_STACK_ENTRY *Stack\r
	34	)\r
	35	/*++\r
	36	\r
	37	Routine Description:\r
	38	\r
	39	This routine determines if a PPI has been installed.\r
	40	The truth value of a GUID is determined by if the PPI has\r
	41	been published and can be queried from the PPI database.\r
	42	\r
	43	Arguments:\r
	44	PeiServices - The PEI core services table.\r
	45	Stack - Reference to EVAL_STACK_ENTRY that contains PPI GUID to check\r
	46	\r
	47	Returns:\r
	48	\r
	49	True if the PPI is already installed.\r
	50	False if the PPI has yet to be installed.\r
	51	\r
	52	--*/\r
	53	{\r
	54	VOID *PeiInstance;\r
	55	EFI_STATUS Status;\r
	56	EFI_GUID PpiGuid;\r
	57	\r
	58	//\r
	59	// If there is no GUID to evaluate, just return current result on stack.\r
	60	//\r
	61	if (Stack->Operator == NULL) {\r
	62	return Stack->Result;\r
	63	}\r
	64	\r
	65	//\r
	66	// Copy the Guid into a locale variable so that there are no\r
	67	// possibilities of alignment faults for cross-compilation \r
	68	// environments such as Intel?Itanium(TM).\r
	69	//\r
	70	CopyMem(&PpiGuid, Stack->Operator, sizeof(EFI_GUID));\r
	71	\r
	72	//\r
	73	// Check if the PPI is installed.\r
	74	//\r
84a99d48	75	Status = PeiServicesLocatePpi(\r
878ddf1f	76	&PpiGuid, // GUID\r
	77	0, // INSTANCE\r
	78	NULL, // EFI_PEI_PPI_DESCRIPTOR\r
	79	&PeiInstance // PPI\r
	80	);\r
	81	\r
	82	if (EFI_ERROR(Status)) {\r
	83	return FALSE;\r
	84	}\r
	85	\r
	86	return TRUE;\r
	87	}\r
	88	\r
	89	\r
	90	EFI_STATUS\r
	91	PeimDispatchReadiness (\r
	92	IN EFI_PEI_SERVICES **PeiServices,\r
	93	IN VOID *DependencyExpression,\r
	94	OUT BOOLEAN *Runnable\r
	95	)\r
	96	/*++\r
	97	\r
	98	Routine Description:\r
	99	\r
	100	This is the POSTFIX version of the dependency evaluator. When a\r
	101	PUSH [PPI GUID] is encountered, a pointer to the GUID is stored on\r
	102	the evaluation stack. When that entry is poped from the evaluation\r
	103	stack, the PPI is checked if it is installed. This method allows\r
	104	some time savings as not all PPIs must be checked for certain\r
	105	operation types (AND, OR).\r
	106	\r
	107	Arguments:\r
	108	\r
	109	PeiServices - Calling context.\r
	110	\r
	111	DependencyExpression - Pointer to a dependency expression. The Grammar adheres to \r
	112	the BNF described above and is stored in postfix notation.\r
	113	Runnable - is True if the driver can be scheduled and False if the driver \r
	114	cannot be scheduled. This is the value that the schedulers \r
	115	should use for deciding the state of the driver.\r
	116	\r
	117	Returns:\r
	118	\r
	119	Status = EFI_SUCCESS if it is a well-formed Grammar\r
	120	EFI_INVALID_PARAMETER if the dependency expression overflows\r
	121	the evaluation stack\r
	122	EFI_INVALID_PARAMETER if the dependency expression underflows\r
	123	the evaluation stack\r
	124	EFI_INVALID_PARAMETER if the dependency expression is not a\r
	125	well-formed Grammar.\r
	126	--*/\r
	127	{\r
	128	EFI_STATUS Status;\r
	129	DEPENDENCY_EXPRESSION_OPERAND *Iterator;\r
	130	EVAL_STACK_ENTRY *StackPtr;\r
	131	EVAL_STACK_ENTRY EvalStack[MAX_GRAMMAR_SIZE];\r
	132	\r
	133	Status = EFI_SUCCESS;\r
	134	Iterator = DependencyExpression;\r
	135	*Runnable = FALSE;\r
	136	\r
	137	StackPtr = &EvalStack[0];\r
	138	\r
	139	while (TRUE) {\r
140	\r
141	switch (*(Iterator++)) {\r
142	\r
143	//\r
144	// For performance reason we put the frequently used items in front of \r
145	// the rarely used items\r
146	//\r
147	\r
148	case (EFI_DEP_PUSH):\r
149	//\r
150	// Check to make sure the dependency grammar doesn't overflow the\r
151	// EvalStack on the push\r
152	//\r
153	if (StackPtr > &EvalStack[MAX_GRAMMAR_SIZE-1]) {\r
154	return EFI_INVALID_PARAMETER;\r
155	}\r
156	\r
157	//\r
158	// Push the pointer to the PUSH opcode operator (pointer to PPI GUID)\r
159	// We will evaluate if the PPI is insalled on the POP operation.\r
160	//\r
161	StackPtr->Operator = (VOID *) Iterator;\r
162	Iterator = Iterator + sizeof (EFI_GUID);\r
163	StackPtr++;\r
164	break;\r
165	\r
166	case (EFI_DEP_AND): \r
167	case (EFI_DEP_OR): \r
168	//\r
169	// Check to make sure the dependency grammar doesn't underflow the\r
170	// EvalStack on the two POPs for the AND operation. Don't need to\r
171	// check for the overflow on PUSHing the result since we already\r
172	// did two POPs.\r
173	//\r
174	if (StackPtr < &EvalStack[2]) {\r
175	return EFI_INVALID_PARAMETER;\r
176	}\r
177	\r
178	//\r
179	// Evaluate the first POPed operator only. If the operand is\r
180	// EFI_DEP_AND and the POPed operator evaluates to FALSE, or the\r
181	// operand is EFI_DEP_OR and the POPed operator evaluates to TRUE,\r
182	// we don't need to check the second operator, and the result will be\r
183	// evaluation of the POPed operator. Otherwise, don't POP the second\r
184	// operator since it will now evaluate to the final result on the\r
185	// next operand that causes a POP.\r
186	// \r
187	StackPtr--;\r
188	//\r
189	// Iterator has increased by 1 after we retrieve the operand, so here we \r
190	// should get the value pointed by (Iterator - 1), in order to obtain the \r
191	// same operand.\r
192	//\r
193	if (*(Iterator - 1) == EFI_DEP_AND) {\r
194	if (!(IsPpiInstalled (PeiServices, StackPtr))) {\r
195	(StackPtr-1)->Result = FALSE;\r
196	(StackPtr-1)->Operator = NULL;\r
197	}\r
198	} else {\r
199	if (IsPpiInstalled (PeiServices, StackPtr)) {\r
200	(StackPtr-1)->Result = TRUE;\r
201	(StackPtr-1)->Operator = NULL;\r
202	}\r
203	}\r
204	break;\r
205	\r
206	case (EFI_DEP_END):\r
207	StackPtr--;\r
208	//\r
209	// Check to make sure EvalStack is balanced. If not, then there is\r
210	// an error in the dependency grammar, so return EFI_INVALID_PARAMETER.\r
211	//\r
212	if (StackPtr != &EvalStack[0]) {\r
213	return EFI_INVALID_PARAMETER;\r
214	}\r
215	*Runnable = IsPpiInstalled (PeiServices, StackPtr);\r
216	return EFI_SUCCESS;\r
217	break;\r
218	\r
219	case (EFI_DEP_NOT): \r
220	//\r
221	// Check to make sure the dependency grammar doesn't underflow the\r
222	// EvalStack on the POP for the NOT operation. Don't need to\r
223	// check for the overflow on PUSHing the result since we already\r
224	// did a POP.\r
225	//\r
226	if (StackPtr < &EvalStack[1]) {\r
227	return EFI_INVALID_PARAMETER;\r
228	}\r
229	(StackPtr-1)->Result = (BOOLEAN) !IsPpiInstalled (PeiServices, (StackPtr-1));\r
230	(StackPtr-1)->Operator = NULL;\r
231	break;\r
232	\r
233	case (EFI_DEP_TRUE):\r
234	case (EFI_DEP_FALSE):\r
235	//\r
236	// Check to make sure the dependency grammar doesn't overflow the\r
237	// EvalStack on the push\r
238	//\r
239	if (StackPtr > &EvalStack[MAX_GRAMMAR_SIZE-1]) {\r
240	return EFI_INVALID_PARAMETER;\r
241	}\r
242	//\r
243	// Iterator has increased by 1 after we retrieve the operand, so here we \r
244	// should get the value pointed by (Iterator - 1), in order to obtain the \r
245	// same operand.\r
246	//\r
247	if (*(Iterator - 1) == EFI_DEP_TRUE) {\r
248	StackPtr->Result = TRUE;\r
249	} else {\r
250	StackPtr->Result = FALSE;\r
251	}\r
252	StackPtr->Operator = NULL;\r
253	StackPtr++;\r
254	break;\r
255	\r
256	default:\r
257	//\r
258	// The grammar should never arrive here\r
259	//\r
260	return EFI_INVALID_PARAMETER;\r
261	break;\r
262	}\r
263	}\r
264	}\r