audk/MdeModulePkg/Core/PiSmmCore/Dependency.c

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/** @file
SMM Driver 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.
Copyright (c) 2009 - 2010, Intel Corporation. All rights reserved.<BR>
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.
**/
#include "PiSmmCore.h"
///
/// EFI_DEP_REPLACE_TRUE - Used to dynamically patch the dependecy expression
/// to save time. A EFI_DEP_PUSH is evauated one an
/// replaced with EFI_DEP_REPLACE_TRUE. If PI spec's Vol 2
/// Driver Execution Environment Core Interface use 0xff
/// as new DEPEX opcode. EFI_DEP_REPLACE_TRUE should be
/// defined to a new value that is not conflicting with PI spec.
///
#define EFI_DEP_REPLACE_TRUE 0xff
///
/// Define the initial size of the dependency expression evaluation stack
///
#define DEPEX_STACK_SIZE_INCREMENT 0x1000
//
// Global stack used to evaluate dependency expressions
//
BOOLEAN *mDepexEvaluationStack = NULL;
BOOLEAN *mDepexEvaluationStackEnd = NULL;
BOOLEAN *mDepexEvaluationStackPointer = NULL;
/**
Grow size of the Depex stack
@retval EFI_SUCCESS Stack successfully growed.
@retval EFI_OUT_OF_RESOURCES There is not enough system memory to grow the stack.
**/
EFI_STATUS
GrowDepexStack (
VOID
)
{
BOOLEAN *NewStack;
UINTN Size;
Size = DEPEX_STACK_SIZE_INCREMENT;
if (mDepexEvaluationStack != NULL) {
Size = Size + (mDepexEvaluationStackEnd - mDepexEvaluationStack);
}
NewStack = AllocatePool (Size * sizeof (BOOLEAN));
if (NewStack == NULL) {
return EFI_OUT_OF_RESOURCES;
}
if (mDepexEvaluationStack != NULL) {
//
// Copy to Old Stack to the New Stack
//
CopyMem (
NewStack,
mDepexEvaluationStack,
(mDepexEvaluationStackEnd - mDepexEvaluationStack) * sizeof (BOOLEAN)
);
//
// Free The Old Stack
//
FreePool (mDepexEvaluationStack);
}
//
// Make the Stack pointer point to the old data in the new stack
//
mDepexEvaluationStackPointer = NewStack + (mDepexEvaluationStackPointer - mDepexEvaluationStack);
mDepexEvaluationStack = NewStack;
mDepexEvaluationStackEnd = NewStack + Size;
return EFI_SUCCESS;
}
/**
Push an element onto the Boolean Stack.
@param Value BOOLEAN to push.
@retval EFI_SUCCESS The value was pushed onto the stack.
@retval EFI_OUT_OF_RESOURCES There is not enough system memory to grow the stack.
**/
EFI_STATUS
PushBool (
IN BOOLEAN Value
)
{
EFI_STATUS Status;
//
// Check for a stack overflow condition
//
if (mDepexEvaluationStackPointer == mDepexEvaluationStackEnd) {
//
// Grow the stack
//
Status = GrowDepexStack ();
if (EFI_ERROR (Status)) {
return Status;
}
}
//
// Push the item onto the stack
//
*mDepexEvaluationStackPointer = Value;
mDepexEvaluationStackPointer++;
return EFI_SUCCESS;
}
/**
Pop an element from the Boolean stack.
@param Value BOOLEAN to pop.
@retval EFI_SUCCESS The value was popped onto the stack.
@retval EFI_ACCESS_DENIED The pop operation underflowed the stack.
**/
EFI_STATUS
PopBool (
OUT BOOLEAN *Value
)
{
//
// Check for a stack underflow condition
//
if (mDepexEvaluationStackPointer == mDepexEvaluationStack) {
return EFI_ACCESS_DENIED;
}
//
// Pop the item off the stack
//
mDepexEvaluationStackPointer--;
*Value = *mDepexEvaluationStackPointer;
return EFI_SUCCESS;
}
/**
This is the POSTFIX version of the dependency evaluator. This code does
not need to handle Before or After, as it is not valid to call this
routine in this case. POSTFIX means all the math is done on top of the stack.
@param DriverEntry DriverEntry element to update.
@retval TRUE If driver is ready to run.
@retval FALSE If driver is not ready to run or some fatal error
was found.
**/
BOOLEAN
SmmIsSchedulable (
IN EFI_SMM_DRIVER_ENTRY *DriverEntry
)
{
EFI_STATUS Status;
UINT8 *Iterator;
BOOLEAN Operator;
BOOLEAN Operator2;
EFI_GUID DriverGuid;
VOID *Interface;
Operator = FALSE;
Operator2 = FALSE;
if (DriverEntry->After || DriverEntry->Before) {
//
// If Before or After Depex skip as SmmInsertOnScheduledQueueWhileProcessingBeforeAndAfter ()
// processes them.
//
return FALSE;
}
DEBUG ((DEBUG_DISPATCH, "Evaluate SMM DEPEX for FFS(%g)\n", &DriverEntry->FileName));
if (DriverEntry->Depex == NULL) {
//
// A NULL Depex means that the SMM driver is not built correctly.
// All SMM drivers must have a valid depex expressiion.
//
DEBUG ((DEBUG_DISPATCH, " RESULT = FALSE (Depex is empty)\n"));
ASSERT (FALSE);
return FALSE;
}
//
// Clean out memory leaks in Depex Boolean stack. Leaks are only caused by
// incorrectly formed DEPEX expressions
//
mDepexEvaluationStackPointer = mDepexEvaluationStack;
Iterator = DriverEntry->Depex;
while (TRUE) {
//
// Check to see if we are attempting to fetch dependency expression instructions
// past the end of the dependency expression.
//
if (((UINTN)Iterator - (UINTN)DriverEntry->Depex) >= DriverEntry->DepexSize) {
DEBUG ((DEBUG_DISPATCH, " RESULT = FALSE (Attempt to fetch past end of depex)\n"));
return FALSE;
}
//
// Look at the opcode of the dependency expression instruction.
//
switch (*Iterator) {
case EFI_DEP_BEFORE:
case EFI_DEP_AFTER:
//
// For a well-formed Dependency Expression, the code should never get here.
// The BEFORE and AFTER are processed prior to this routine's invocation.
// If the code flow arrives at this point, there was a BEFORE or AFTER
// that were not the first opcodes.
//
DEBUG ((DEBUG_DISPATCH, " RESULT = FALSE (Unexpected BEFORE or AFTER opcode)\n"));
ASSERT (FALSE);
case EFI_DEP_PUSH:
//
// Push operator is followed by a GUID. Test to see if the GUID protocol
// is installed and push the boolean result on the stack.
//
CopyMem (&DriverGuid, Iterator + 1, sizeof (EFI_GUID));
Status = SmmLocateProtocol (&DriverGuid, NULL, &Interface);
if (EFI_ERROR (Status)) {
//
// For SMM Driver, it may depend on uefi protocols
//
Status = gBS->LocateProtocol (&DriverGuid, NULL, &Interface);
}
if (EFI_ERROR (Status)) {
DEBUG ((DEBUG_DISPATCH, " PUSH GUID(%g) = FALSE\n", &DriverGuid));
Status = PushBool (FALSE);
} else {
DEBUG ((DEBUG_DISPATCH, " PUSH GUID(%g) = TRUE\n", &DriverGuid));
*Iterator = EFI_DEP_REPLACE_TRUE;
Status = PushBool (TRUE);
}
if (EFI_ERROR (Status)) {
DEBUG ((DEBUG_DISPATCH, " RESULT = FALSE (Unexpected error)\n"));
return FALSE;
}
Iterator += sizeof (EFI_GUID);
break;
case EFI_DEP_AND:
DEBUG ((DEBUG_DISPATCH, " AND\n"));
Status = PopBool (&Operator);
if (EFI_ERROR (Status)) {
DEBUG ((DEBUG_DISPATCH, " RESULT = FALSE (Unexpected error)\n"));
return FALSE;
}
Status = PopBool (&Operator2);
if (EFI_ERROR (Status)) {
DEBUG ((DEBUG_DISPATCH, " RESULT = FALSE (Unexpected error)\n"));
return FALSE;
}
Status = PushBool ((BOOLEAN)(Operator && Operator2));
if (EFI_ERROR (Status)) {
DEBUG ((DEBUG_DISPATCH, " RESULT = FALSE (Unexpected error)\n"));
return FALSE;
}
break;
case EFI_DEP_OR:
DEBUG ((DEBUG_DISPATCH, " OR\n"));
Status = PopBool (&Operator);
if (EFI_ERROR (Status)) {
DEBUG ((DEBUG_DISPATCH, " RESULT = FALSE (Unexpected error)\n"));
return FALSE;
}
Status = PopBool (&Operator2);
if (EFI_ERROR (Status)) {
DEBUG ((DEBUG_DISPATCH, " RESULT = FALSE (Unexpected error)\n"));
return FALSE;
}
Status = PushBool ((BOOLEAN)(Operator || Operator2));
if (EFI_ERROR (Status)) {
DEBUG ((DEBUG_DISPATCH, " RESULT = FALSE (Unexpected error)\n"));
return FALSE;
}
break;
case EFI_DEP_NOT:
DEBUG ((DEBUG_DISPATCH, " NOT\n"));
Status = PopBool (&Operator);
if (EFI_ERROR (Status)) {
DEBUG ((DEBUG_DISPATCH, " RESULT = FALSE (Unexpected error)\n"));
return FALSE;
}
Status = PushBool ((BOOLEAN)(!Operator));
if (EFI_ERROR (Status)) {
DEBUG ((DEBUG_DISPATCH, " RESULT = FALSE (Unexpected error)\n"));
return FALSE;
}
break;
case EFI_DEP_TRUE:
DEBUG ((DEBUG_DISPATCH, " TRUE\n"));
Status = PushBool (TRUE);
if (EFI_ERROR (Status)) {
DEBUG ((DEBUG_DISPATCH, " RESULT = FALSE (Unexpected error)\n"));
return FALSE;
}
break;
case EFI_DEP_FALSE:
DEBUG ((DEBUG_DISPATCH, " FALSE\n"));
Status = PushBool (FALSE);
if (EFI_ERROR (Status)) {
DEBUG ((DEBUG_DISPATCH, " RESULT = FALSE (Unexpected error)\n"));
return FALSE;
}
break;
case EFI_DEP_END:
DEBUG ((DEBUG_DISPATCH, " END\n"));
Status = PopBool (&Operator);
if (EFI_ERROR (Status)) {
DEBUG ((DEBUG_DISPATCH, " RESULT = FALSE (Unexpected error)\n"));
return FALSE;
}
DEBUG ((DEBUG_DISPATCH, " RESULT = %a\n", Operator ? "TRUE" : "FALSE"));
return Operator;
case EFI_DEP_REPLACE_TRUE:
CopyMem (&DriverGuid, Iterator + 1, sizeof (EFI_GUID));
DEBUG ((DEBUG_DISPATCH, " PUSH GUID(%g) = TRUE\n", &DriverGuid));
Status = PushBool (TRUE);
if (EFI_ERROR (Status)) {
DEBUG ((DEBUG_DISPATCH, " RESULT = FALSE (Unexpected error)\n"));
return FALSE;
}
Iterator += sizeof (EFI_GUID);
break;
default:
DEBUG ((DEBUG_DISPATCH, " RESULT = FALSE (Unknown opcode)\n"));
goto Done;
}
//
// Skip over the Dependency Op Code we just processed in the switch.
// The math is done out of order, but it should not matter. That is
// we may add in the sizeof (EFI_GUID) before we account for the OP Code.
// This is not an issue, since we just need the correct end result. You
// need to be careful using Iterator in the loop as it's intermediate value
// may be strange.
//
Iterator++;
}
Done:
return FALSE;
}