[mirror_edk2.git] / MdeModulePkg / 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
//\r
// Include common header file for this module.\r
//\r
#include "CommonHeader.h"\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
  DEPENDENCY_EXPRESSION_OPERAND  *Iterator;\r
  EVAL_STACK_ENTRY               *StackPtr;\r
  EVAL_STACK_ENTRY               EvalStack[MAX_GRAMMAR_SIZE];\r
\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
192f6d4c	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	//\r
	27	// Include common header file for this module.\r
	28	//\r
	29	#include "CommonHeader.h"\r
	30	\r
	31	#include <PeiMain.h>\r
	32	#include "dependency.h"\r
	33	\r
	34	STATIC\r
	35	BOOLEAN\r
	36	IsPpiInstalled (\r
	37	IN EFI_PEI_SERVICES **PeiServices,\r
	38	IN EVAL_STACK_ENTRY *Stack\r
	39	)\r
	40	/*++\r
	41	\r
	42	Routine Description:\r
	43	\r
	44	This routine determines if a PPI has been installed.\r
	45	The truth value of a GUID is determined by if the PPI has\r
	46	been published and can be queried from the PPI database.\r
	47	\r
	48	Arguments:\r
	49	PeiServices - The PEI core services table.\r
	50	Stack - Reference to EVAL_STACK_ENTRY that contains PPI GUID to check\r
	51	\r
	52	Returns:\r
	53	\r
	54	True if the PPI is already installed.\r
	55	False if the PPI has yet to be installed.\r
	56	\r
	57	--*/\r
	58	{\r
	59	VOID *PeiInstance;\r
	60	EFI_STATUS Status;\r
	61	EFI_GUID PpiGuid;\r
	62	\r
	63	//\r
	64	// If there is no GUID to evaluate, just return current result on stack.\r
65	//\r
66	if (Stack->Operator == NULL) {\r
67	return Stack->Result;\r
68	}\r
69	\r
70	//\r
71	// Copy the Guid into a locale variable so that there are no\r
72	// possibilities of alignment faults for cross-compilation \r
73	// environments such as Intel?Itanium(TM).\r
74	//\r
75	CopyMem(&PpiGuid, Stack->Operator, sizeof(EFI_GUID));\r
76	\r
77	//\r
78	// Check if the PPI is installed.\r
79	//\r
80	Status = PeiServicesLocatePpi(\r
81	&PpiGuid, // GUID\r
82	0, // INSTANCE\r
83	NULL, // EFI_PEI_PPI_DESCRIPTOR\r
84	&PeiInstance // PPI\r
85	);\r
86	\r
87	if (EFI_ERROR(Status)) {\r
88	return FALSE;\r
89	}\r
90	\r
91	return TRUE;\r
92	}\r
93	\r
94	\r
95	EFI_STATUS\r
96	PeimDispatchReadiness (\r
97	IN EFI_PEI_SERVICES **PeiServices,\r
98	IN VOID *DependencyExpression,\r
99	OUT BOOLEAN *Runnable\r
100	)\r
101	/*++\r
102	\r
103	Routine Description:\r
104	\r
105	This is the POSTFIX version of the dependency evaluator. When a\r
106	PUSH [PPI GUID] is encountered, a pointer to the GUID is stored on\r
107	the evaluation stack. When that entry is poped from the evaluation\r
108	stack, the PPI is checked if it is installed. This method allows\r
109	some time savings as not all PPIs must be checked for certain\r
110	operation types (AND, OR).\r
111	\r
112	Arguments:\r
113	\r
114	PeiServices - Calling context.\r
115	\r
116	DependencyExpression - Pointer to a dependency expression. The Grammar adheres to \r
117	the BNF described above and is stored in postfix notation.\r
118	Runnable - is True if the driver can be scheduled and False if the driver \r
119	cannot be scheduled. This is the value that the schedulers \r
120	should use for deciding the state of the driver.\r
121	\r
122	Returns:\r
123	\r
124	Status = EFI_SUCCESS if it is a well-formed Grammar\r
125	EFI_INVALID_PARAMETER if the dependency expression overflows\r
126	the evaluation stack\r
127	EFI_INVALID_PARAMETER if the dependency expression underflows\r
128	the evaluation stack\r
129	EFI_INVALID_PARAMETER if the dependency expression is not a\r
130	well-formed Grammar.\r
131	--*/\r
132	{\r
133	DEPENDENCY_EXPRESSION_OPERAND *Iterator;\r
134	EVAL_STACK_ENTRY *StackPtr;\r
135	EVAL_STACK_ENTRY EvalStack[MAX_GRAMMAR_SIZE];\r
136	\r
137	Iterator = DependencyExpression;\r
138	*Runnable = FALSE;\r
139	\r
140	StackPtr = &EvalStack[0];\r
141	\r
142	while (TRUE) {\r
143	\r
144	switch (*(Iterator++)) {\r
145	\r
146	//\r
147	// For performance reason we put the frequently used items in front of \r
148	// the rarely used items\r
149	//\r
150	\r
151	case (EFI_DEP_PUSH):\r
152	//\r
153	// Check to make sure the dependency grammar doesn't overflow the\r
154	// EvalStack on the push\r
155	//\r
156	if (StackPtr > &EvalStack[MAX_GRAMMAR_SIZE-1]) {\r
157	return EFI_INVALID_PARAMETER;\r
158	}\r
159	\r
160	//\r
161	// Push the pointer to the PUSH opcode operator (pointer to PPI GUID)\r
162	// We will evaluate if the PPI is insalled on the POP operation.\r
163	//\r
164	StackPtr->Operator = (VOID *) Iterator;\r
165	Iterator = Iterator + sizeof (EFI_GUID);\r
166	StackPtr++;\r
167	break;\r
168	\r
169	case (EFI_DEP_AND): \r
170	case (EFI_DEP_OR): \r
171	//\r
172	// Check to make sure the dependency grammar doesn't underflow the\r
173	// EvalStack on the two POPs for the AND operation. Don't need to\r
174	// check for the overflow on PUSHing the result since we already\r
175	// did two POPs.\r
176	//\r
177	if (StackPtr < &EvalStack[2]) {\r
178	return EFI_INVALID_PARAMETER;\r
179	}\r
180	\r
181	//\r
182	// Evaluate the first POPed operator only. If the operand is\r
183	// EFI_DEP_AND and the POPed operator evaluates to FALSE, or the\r
184	// operand is EFI_DEP_OR and the POPed operator evaluates to TRUE,\r
185	// we don't need to check the second operator, and the result will be\r
186	// evaluation of the POPed operator. Otherwise, don't POP the second\r
187	// operator since it will now evaluate to the final result on the\r
188	// next operand that causes a POP.\r
189	// \r
190	StackPtr--;\r
191	//\r
192	// Iterator has increased by 1 after we retrieve the operand, so here we \r
193	// should get the value pointed by (Iterator - 1), in order to obtain the \r
194	// same operand.\r
195	//\r
196	if (*(Iterator - 1) == EFI_DEP_AND) {\r
197	if (!(IsPpiInstalled (PeiServices, StackPtr))) {\r
198	(StackPtr-1)->Result = FALSE;\r
199	(StackPtr-1)->Operator = NULL;\r
200	}\r
201	} else {\r
202	if (IsPpiInstalled (PeiServices, StackPtr)) {\r
203	(StackPtr-1)->Result = TRUE;\r
204	(StackPtr-1)->Operator = NULL;\r
205	}\r
206	}\r
207	break;\r
208	\r
209	case (EFI_DEP_END):\r
210	StackPtr--;\r
211	//\r
212	// Check to make sure EvalStack is balanced. If not, then there is\r
213	// an error in the dependency grammar, so return EFI_INVALID_PARAMETER.\r
214	//\r
215	if (StackPtr != &EvalStack[0]) {\r
216	return EFI_INVALID_PARAMETER;\r
217	}\r
218	*Runnable = IsPpiInstalled (PeiServices, StackPtr);\r
219	return EFI_SUCCESS;\r
220	break;\r
221	\r
222	case (EFI_DEP_NOT): \r
223	//\r
224	// Check to make sure the dependency grammar doesn't underflow the\r
225	// EvalStack on the POP for the NOT operation. Don't need to\r
226	// check for the overflow on PUSHing the result since we already\r
227	// did a POP.\r
228	//\r
229	if (StackPtr < &EvalStack[1]) {\r
230	return EFI_INVALID_PARAMETER;\r
231	}\r
232	(StackPtr-1)->Result = (BOOLEAN) !IsPpiInstalled (PeiServices, (StackPtr-1));\r
233	(StackPtr-1)->Operator = NULL;\r
234	break;\r
235	\r
236	case (EFI_DEP_TRUE):\r
237	case (EFI_DEP_FALSE):\r
238	//\r
239	// Check to make sure the dependency grammar doesn't overflow the\r
240	// EvalStack on the push\r
241	//\r
242	if (StackPtr > &EvalStack[MAX_GRAMMAR_SIZE-1]) {\r
243	return EFI_INVALID_PARAMETER;\r
244	}\r
245	//\r
246	// Iterator has increased by 1 after we retrieve the operand, so here we \r
247	// should get the value pointed by (Iterator - 1), in order to obtain the \r
248	// same operand.\r
249	//\r
250	if (*(Iterator - 1) == EFI_DEP_TRUE) {\r
251	StackPtr->Result = TRUE;\r
252	} else {\r
253	StackPtr->Result = FALSE;\r
254	}\r
255	StackPtr->Operator = NULL;\r
256	StackPtr++;\r
257	break;\r
258	\r
259	default:\r
260	//\r
261	// The grammar should never arrive here\r
262	//\r
263	return EFI_INVALID_PARAMETER;\r
264	break;\r
265	}\r
266	}\r
267	}\r