mirror of https://github.com/acidanthera/audk.git
164 lines
3.2 KiB
C
164 lines
3.2 KiB
C
/** @file
|
|
|
|
Task priority (TPL) function
|
|
|
|
Copyright (c) 2006 - 2008, 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.
|
|
|
|
**/
|
|
|
|
#include <DxeMain.h>
|
|
|
|
|
|
/**
|
|
Set Interrupt State.
|
|
|
|
@param Enable The state of enable or disable interrupt
|
|
|
|
**/
|
|
STATIC
|
|
VOID
|
|
CoreSetInterruptState (
|
|
IN BOOLEAN Enable
|
|
)
|
|
{
|
|
if (gCpu != NULL) {
|
|
if (Enable) {
|
|
gCpu->EnableInterrupt(gCpu);
|
|
} else {
|
|
gCpu->DisableInterrupt(gCpu);
|
|
}
|
|
}
|
|
}
|
|
|
|
//
|
|
// Return the highest set bit
|
|
//
|
|
|
|
/**
|
|
Return the highest set bit.
|
|
|
|
@param Number The value to check
|
|
|
|
@return Bit position of the highest set bit
|
|
|
|
**/
|
|
UINTN
|
|
CoreHighestSetBit (
|
|
IN UINTN Number
|
|
)
|
|
{
|
|
UINTN msb;
|
|
|
|
msb = 31;
|
|
while ((msb > 0) && ((Number & (UINTN)(1 << msb)) == 0)) {
|
|
msb--;
|
|
}
|
|
|
|
return msb;
|
|
}
|
|
|
|
|
|
|
|
|
|
/**
|
|
Raise the task priority level to the new level.
|
|
High level is implemented by disabling processor interrupts.
|
|
|
|
@param NewTpl New task priority level
|
|
|
|
@return The previous task priority level
|
|
|
|
**/
|
|
EFI_TPL
|
|
EFIAPI
|
|
CoreRaiseTpl (
|
|
IN EFI_TPL NewTpl
|
|
)
|
|
{
|
|
EFI_TPL OldTpl;
|
|
|
|
OldTpl = gEfiCurrentTpl;
|
|
ASSERT (OldTpl <= NewTpl);
|
|
ASSERT (VALID_TPL (NewTpl));
|
|
|
|
//
|
|
// If raising to high level, disable interrupts
|
|
//
|
|
if (NewTpl >= TPL_HIGH_LEVEL && OldTpl < TPL_HIGH_LEVEL) {
|
|
CoreSetInterruptState (FALSE);
|
|
}
|
|
|
|
//
|
|
// Set the new value
|
|
//
|
|
gEfiCurrentTpl = NewTpl;
|
|
|
|
return OldTpl;
|
|
}
|
|
|
|
|
|
|
|
|
|
/**
|
|
Lowers the task priority to the previous value. If the new
|
|
priority unmasks events at a higher priority, they are dispatched.
|
|
|
|
@param NewTpl New, lower, task priority
|
|
|
|
**/
|
|
VOID
|
|
EFIAPI
|
|
CoreRestoreTpl (
|
|
IN EFI_TPL NewTpl
|
|
)
|
|
{
|
|
EFI_TPL OldTpl;
|
|
|
|
OldTpl = gEfiCurrentTpl;
|
|
ASSERT (NewTpl <= OldTpl);
|
|
ASSERT (VALID_TPL (NewTpl));
|
|
|
|
//
|
|
// If lowering below HIGH_LEVEL, make sure
|
|
// interrupts are enabled
|
|
//
|
|
|
|
if (OldTpl >= TPL_HIGH_LEVEL && NewTpl < TPL_HIGH_LEVEL) {
|
|
gEfiCurrentTpl = TPL_HIGH_LEVEL;
|
|
}
|
|
|
|
//
|
|
// Dispatch any pending events
|
|
//
|
|
|
|
while ((-2 << NewTpl) & gEventPending) {
|
|
gEfiCurrentTpl = CoreHighestSetBit (gEventPending);
|
|
if (gEfiCurrentTpl < TPL_HIGH_LEVEL) {
|
|
CoreSetInterruptState (TRUE);
|
|
}
|
|
CoreDispatchEventNotifies (gEfiCurrentTpl);
|
|
}
|
|
|
|
//
|
|
// Set the new value
|
|
//
|
|
|
|
gEfiCurrentTpl = NewTpl;
|
|
|
|
//
|
|
// If lowering below HIGH_LEVEL, make sure
|
|
// interrupts are enabled
|
|
//
|
|
if (gEfiCurrentTpl < TPL_HIGH_LEVEL) {
|
|
CoreSetInterruptState (TRUE);
|
|
}
|
|
|
|
}
|