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Diffstat (limited to 'Core/CORE_PEI/CORE_PEI_PI/dependency.c')
| -rw-r--r-- | Core/CORE_PEI/CORE_PEI_PI/dependency.c | 265 |
1 files changed, 265 insertions, 0 deletions
diff --git a/Core/CORE_PEI/CORE_PEI_PI/dependency.c b/Core/CORE_PEI/CORE_PEI_PI/dependency.c new file mode 100644 index 0000000..f890a42 --- /dev/null +++ b/Core/CORE_PEI/CORE_PEI_PI/dependency.c @@ -0,0 +1,265 @@ +/*++ + +Copyright (c) 2004 - 2007, Intel Corporation +All rights reserved. This program and the accompanying materials +are licensed and made available under the terms and conditions of the BSD License +which accompanies this distribution. The full text of the license may be found at +http://opensource.org/licenses/bsd-license.php + +THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, +WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED. + +Module Name: + + dependency.c + +Abstract: + + PEI Dispatcher Dependency Evaluator + + This routine evaluates a dependency expression (DEPENDENCY_EXPRESSION) to determine + if a driver can be scheduled for execution. The criteria for + schedulability is that the dependency expression is satisfied. + +--*/ + +#include "Tiano.h" +#include "PeiCore.h" +#include "PeiLib.h" +#include "EfiDependency.h" +#include "Dependency.h" + +STATIC +BOOLEAN +IsPpiInstalled ( + IN EFI_PEI_SERVICES **PeiServices, + IN EVAL_STACK_ENTRY *Stack + ) +/*++ + +Routine Description: + + This routine determines if a PPI has been installed. + The truth value of a GUID is determined by if the PPI has + been published and can be queried from the PPI database. + +Arguments: + PeiServices - The PEI core services table. + Stack - Reference to EVAL_STACK_ENTRY that contains PPI GUID to check + +Returns: + + True if the PPI is already installed. + False if the PPI has yet to be installed. + +--*/ +{ + VOID *PeiInstance; + EFI_STATUS Status; + EFI_GUID PpiGuid; + + // + // If there is no GUID to evaluate, just return current result on stack. + // + if (Stack->Operator == NULL) { + return Stack->Result; + } + + // + // Copy the Guid into a locale variable so that there are no + // possibilities of alignment faults for cross-compilation + // environments such as Intel?Itanium(TM). + // + PeiCoreCopyMem(&PpiGuid, Stack->Operator, sizeof(EFI_GUID)); + + // + // Check if the PPI is installed. + // + Status = (**PeiServices).LocatePpi( + PeiServices, + &PpiGuid, // GUID + 0, // INSTANCE + NULL, // EFI_PEI_PPI_DESCRIPTOR + &PeiInstance // PPI + ); + + if (EFI_ERROR(Status)) { + return FALSE; + } + + return TRUE; +} + + +BOOLEAN +PeimDispatchReadiness ( + IN EFI_PEI_SERVICES **PeiServices, + IN VOID *DependencyExpression + ) +/*++ + +Routine Description: + + This is the POSTFIX version of the dependency evaluator. When a + PUSH [PPI GUID] is encountered, a pointer to the GUID is stored on + the evaluation stack. When that entry is poped from the evaluation + stack, the PPI is checked if it is installed. This method allows + some time savings as not all PPIs must be checked for certain + operation types (AND, OR). + +Arguments: + + PeiServices - Calling context. + + DependencyExpression - Pointer to a dependency expression. The Grammar adheres to + the BNF described above and is stored in postfix notation. + Runnable - is True if the driver can be scheduled and False if the driver + cannot be scheduled. This is the value that the schedulers + should use for deciding the state of the driver. + +Returns: + + Status = EFI_SUCCESS if it is a well-formed Grammar + EFI_INVALID_PARAMETER if the dependency expression overflows + the evaluation stack + EFI_INVALID_PARAMETER if the dependency expression underflows + the evaluation stack + EFI_INVALID_PARAMETER if the dependency expression is not a + well-formed Grammar. +--*/ +{ + EFI_STATUS Status; + DEPENDENCY_EXPRESSION_OPERAND *Iterator; + EVAL_STACK_ENTRY *StackPtr; + EVAL_STACK_ENTRY EvalStack[MAX_GRAMMAR_SIZE]; + + Status = EFI_SUCCESS; + Iterator = DependencyExpression; + + StackPtr = &EvalStack[0]; + + while (TRUE) { + + switch (*(Iterator++)) { + + // + // For performance reason we put the frequently used items in front of + // the rarely used items + // + + case (EFI_DEP_PUSH): + // + // Check to make sure the dependency grammar doesn't overflow the + // EvalStack on the push + // + if (StackPtr > &EvalStack[MAX_GRAMMAR_SIZE-1]) { + return FALSE; + } + + // + // Push the pointer to the PUSH opcode operator (pointer to PPI GUID) + // We will evaluate if the PPI is insalled on the POP operation. + // + StackPtr->Operator = (VOID *) Iterator; + Iterator = Iterator + sizeof (EFI_GUID); + StackPtr++; + break; + + case (EFI_DEP_AND): + case (EFI_DEP_OR): + // + // Check to make sure the dependency grammar doesn't underflow the + // EvalStack on the two POPs for the AND operation. Don't need to + // check for the overflow on PUSHing the result since we already + // did two POPs. + // + if (StackPtr < &EvalStack[2]) { + return FALSE; + } + + // + // Evaluate the first POPed operator only. If the operand is + // EFI_DEP_AND and the POPed operator evaluates to FALSE, or the + // operand is EFI_DEP_OR and the POPed operator evaluates to TRUE, + // we don't need to check the second operator, and the result will be + // evaluation of the POPed operator. Otherwise, don't POP the second + // operator since it will now evaluate to the final result on the + // next operand that causes a POP. + // + StackPtr--; + // + // Iterator has increased by 1 after we retrieve the operand, so here we + // should get the value pointed by (Iterator - 1), in order to obtain the + // same operand. + // + if (*(Iterator - 1) == EFI_DEP_AND) { + if (!(IsPpiInstalled (PeiServices, StackPtr))) { + (StackPtr-1)->Result = FALSE; + (StackPtr-1)->Operator = NULL; + } + } else { + if (IsPpiInstalled (PeiServices, StackPtr)) { + (StackPtr-1)->Result = TRUE; + (StackPtr-1)->Operator = NULL; + } + } + break; + + case (EFI_DEP_END): + StackPtr--; + // + // Check to make sure EvalStack is balanced. If not, then there is + // an error in the dependency grammar, so return EFI_INVALID_PARAMETER. + // + if (StackPtr != &EvalStack[0]) { + return FALSE; + } + return IsPpiInstalled (PeiServices, StackPtr); + break; + + case (EFI_DEP_NOT): + // + // Check to make sure the dependency grammar doesn't underflow the + // EvalStack on the POP for the NOT operation. Don't need to + // check for the overflow on PUSHing the result since we already + // did a POP. + // + if (StackPtr < &EvalStack[1]) { + return FALSE; + } + (StackPtr-1)->Result = (BOOLEAN) !IsPpiInstalled (PeiServices, (StackPtr-1)); + (StackPtr-1)->Operator = NULL; + break; + + case (EFI_DEP_TRUE): + case (EFI_DEP_FALSE): + // + // Check to make sure the dependency grammar doesn't overflow the + // EvalStack on the push + // + if (StackPtr > &EvalStack[MAX_GRAMMAR_SIZE-1]) { + return FALSE; + } + // + // Iterator has increased by 1 after we retrieve the operand, so here we + // should get the value pointed by (Iterator - 1), in order to obtain the + // same operand. + // + if (*(Iterator - 1) == EFI_DEP_TRUE) { + StackPtr->Result = TRUE; + } else { + StackPtr->Result = FALSE; + } + StackPtr->Operator = NULL; + StackPtr++; + break; + + default: + // + // The grammar should never arrive here + // + return FALSE; + break; + } + } +} |