4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync DXE Dispatcher Dependency Evaluator.
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync This routine evaluates a dependency expression (DEPENDENCY_EXPRESSION) to determine
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync if a driver can be scheduled for execution. The criteria for
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync schedulability is that the dependency expression is satisfied.
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsyncCopyright (c) 2006 - 2010, Intel Corporation. All rights reserved.<BR>
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsyncThis program and the accompanying materials
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsyncare licensed and made available under the terms and conditions of the BSD License
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsyncwhich accompanies this distribution. The full text of the license may be found at
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsyncTHE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsyncWITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync// Global stack used to evaluate dependency expressions
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync// Worker functions
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync Grow size of the Depex stack
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync @retval EFI_SUCCESS Stack successfully growed.
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync @retval EFI_OUT_OF_RESOURCES There is not enough system memory to grow the stack.
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync Size = Size + (mDepexEvaluationStackEnd - mDepexEvaluationStack);
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync // Copy to Old Stack to the New Stack
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync (mDepexEvaluationStackEnd - mDepexEvaluationStack) * sizeof (BOOLEAN)
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync // Free The Old Stack
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync // Make the Stack pointer point to the old data in the new stack
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync mDepexEvaluationStackPointer = NewStack + (mDepexEvaluationStackPointer - mDepexEvaluationStack);
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync Push an element onto the Boolean Stack.
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync @param Value BOOLEAN to push.
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync @retval EFI_SUCCESS The value was pushed onto the stack.
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync @retval EFI_OUT_OF_RESOURCES There is not enough system memory to grow the stack.
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync // Check for a stack overflow condition
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync if (mDepexEvaluationStackPointer == mDepexEvaluationStackEnd) {
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync // Grow the stack
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync // Push the item onto the stack
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync Pop an element from the Boolean stack.
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync @param Value BOOLEAN to pop.
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync @retval EFI_SUCCESS The value was popped onto the stack.
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync @retval EFI_ACCESS_DENIED The pop operation underflowed the stack.
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync // Check for a stack underflow condition
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync if (mDepexEvaluationStackPointer == mDepexEvaluationStack) {
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync // Pop the item off the stack
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync Preprocess dependency expression and update DriverEntry to reflect the
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync state of Before, After, and SOR dependencies. If DriverEntry->Before
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync or DriverEntry->After is set it will never be cleared. If SOR is set
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync it will be cleared by CoreSchedule(), and then the driver can be
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync dispatched.
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync @param DriverEntry DriverEntry element to update .
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync @retval EFI_SUCCESS It always works.
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync CopyMem (&DriverEntry->BeforeAfterGuid, Iterator + 1, sizeof (EFI_GUID));
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync This is the POSTFIX version of the dependency evaluator. This code does
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync not need to handle Before or After, as it is not valid to call this
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync routine in this case. The SOR is just ignored and is a nop in the grammer.
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync POSTFIX means all the math is done on top of the stack.
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync @param DriverEntry DriverEntry element to update.
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync @retval TRUE If driver is ready to run.
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync @retval FALSE If driver is not ready to run or some fatal error
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync // If Before or After Depex skip as CoreInsertOnScheduledQueueWhileProcessingBeforeAndAfter ()
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync // processes them.
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync DEBUG ((DEBUG_DISPATCH, "Evaluate DXE DEPEX for FFS(%g)\n", &DriverEntry->FileName));
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync // A NULL Depex means treat the driver like an UEFI 2.0 thing.
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync DEBUG ((DEBUG_DISPATCH, " All UEFI Services Available = "));
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync DEBUG ((DEBUG_DISPATCH, "FALSE\n RESULT = FALSE\n"));
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync DEBUG ((DEBUG_DISPATCH, "TRUE\n RESULT = TRUE\n"));
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync // Clean out memory leaks in Depex Boolean stack. Leaks are only caused by
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync // incorrectly formed DEPEX expressions
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync mDepexEvaluationStackPointer = mDepexEvaluationStack;
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync // Check to see if we are attempting to fetch dependency expression instructions
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync // past the end of the dependency expression.
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync if (((UINTN)Iterator - (UINTN)DriverEntry->Depex) >= DriverEntry->DepexSize) {
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync DEBUG ((DEBUG_DISPATCH, " RESULT = FALSE (Attempt to fetch past end of depex)\n"));
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync // Look at the opcode of the dependency expression instruction.
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync // For a well-formed Dependency Expression, the code should never get here.
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync // The BEFORE and AFTER are processed prior to this routine's invocation.
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync // If the code flow arrives at this point, there was a BEFORE or AFTER
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync // that were not the first opcodes.
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync DEBUG ((DEBUG_DISPATCH, " RESULT = FALSE (Unexpected BEFORE or AFTER opcode)\n"));
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync // These opcodes can only appear once as the first opcode. If it is found
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync // at any other location, then the dependency expression evaluates to FALSE
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync DEBUG ((DEBUG_DISPATCH, " RESULT = FALSE (Unexpected SOR opcode)\n"));
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync // Otherwise, it is the first opcode and should be treated as a NOP.
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync // Push operator is followed by a GUID. Test to see if the GUID protocol
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync // is installed and push the boolean result on the stack.
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync CopyMem (&DriverGuid, Iterator + 1, sizeof (EFI_GUID));
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync Status = CoreLocateProtocol (&DriverGuid, NULL, &Interface);
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync DEBUG ((DEBUG_DISPATCH, " PUSH GUID(%g) = FALSE\n", &DriverGuid));
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync DEBUG ((DEBUG_DISPATCH, " PUSH GUID(%g) = TRUE\n", &DriverGuid));
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync DEBUG ((DEBUG_DISPATCH, " RESULT = FALSE (Unexpected error)\n"));
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync DEBUG ((DEBUG_DISPATCH, " RESULT = FALSE (Unexpected error)\n"));
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync DEBUG ((DEBUG_DISPATCH, " RESULT = FALSE (Unexpected error)\n"));
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync Status = PushBool ((BOOLEAN)(Operator && Operator2));
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync DEBUG ((DEBUG_DISPATCH, " RESULT = FALSE (Unexpected error)\n"));
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync DEBUG ((DEBUG_DISPATCH, " RESULT = FALSE (Unexpected error)\n"));
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync DEBUG ((DEBUG_DISPATCH, " RESULT = FALSE (Unexpected error)\n"));
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync Status = PushBool ((BOOLEAN)(Operator || Operator2));
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync DEBUG ((DEBUG_DISPATCH, " RESULT = FALSE (Unexpected error)\n"));
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync DEBUG ((DEBUG_DISPATCH, " RESULT = FALSE (Unexpected error)\n"));
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync DEBUG ((DEBUG_DISPATCH, " RESULT = FALSE (Unexpected error)\n"));
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync DEBUG ((DEBUG_DISPATCH, " RESULT = FALSE (Unexpected error)\n"));
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync DEBUG ((DEBUG_DISPATCH, " RESULT = FALSE (Unexpected error)\n"));
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync DEBUG ((DEBUG_DISPATCH, " RESULT = FALSE (Unexpected error)\n"));
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync DEBUG ((DEBUG_DISPATCH, " RESULT = %a\n", Operator ? "TRUE" : "FALSE"));
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync CopyMem (&DriverGuid, Iterator + 1, sizeof (EFI_GUID));
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync DEBUG ((DEBUG_DISPATCH, " PUSH GUID(%g) = TRUE\n", &DriverGuid));
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync DEBUG ((DEBUG_DISPATCH, " RESULT = FALSE (Unexpected error)\n"));
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync DEBUG ((DEBUG_DISPATCH, " RESULT = FALSE (Unknown opcode)\n"));
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync // Skip over the Dependency Op Code we just processed in the switch.
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync // The math is done out of order, but it should not matter. That is
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync // we may add in the sizeof (EFI_GUID) before we account for the OP Code.
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync // This is not an issue, since we just need the correct end result. You
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync // need to be careful using Iterator in the loop as it's intermediate value
4fd606d1f5abe38e1f42c38de1d2e895166bd0f4vboxsync // may be strange.