MdeModulePkg/Core/Dxe/Event/Tpl.c

   1 /** @file
   2   Task priority (TPL) functions.
   3
   4 Copyright (c) 2006 - 2015, Intel Corporation. All rights reserved.<BR>
   5 This program and the accompanying materials
   6 are licensed and made available under the terms and conditions of the BSD License
   7 which accompanies this distribution.  The full text of the license may be found at
   8 http://opensource.org/licenses/bsd-license.php
   9
  10 THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  11 WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  12
  13 **/
  14
  15 #include "DxeMain.h"
  16 #include "Event.h"
  17
  18 /**
  19   Set Interrupt State.
  20
  21   @param  Enable  The state of enable or disable interrupt
  22
  23 **/
  24 VOID
  25 CoreSetInterruptState (
  26   IN BOOLEAN      Enable
  27   )
  28 {
  29   EFI_STATUS  Status;
  30   BOOLEAN     InSmm;
  31
  32   if (gCpu == NULL) {
  33     return;
  34   }
  35   if (!Enable) {
  36     gCpu->DisableInterrupt (gCpu);
  37     return;
  38   }
  39   if (gSmmBase2 == NULL) {
  40     gCpu->EnableInterrupt (gCpu);
  41     return;
  42   }
  43   Status = gSmmBase2->InSmm (gSmmBase2, &InSmm);
  44   if (!EFI_ERROR (Status) && !InSmm) {
  45     gCpu->EnableInterrupt(gCpu);
  46   }
  47 }
  48
  49
  50 /**
  51   Raise the task priority level to the new level.
  52   High level is implemented by disabling processor interrupts.
  53
  54   @param  NewTpl  New task priority level
  55
  56   @return The previous task priority level
  57
  58 **/
  59 EFI_TPL
  60 EFIAPI
  61 CoreRaiseTpl (
  62   IN EFI_TPL      NewTpl
  63   )
  64 {
  65   EFI_TPL     OldTpl;
  66
  67   OldTpl = gEfiCurrentTpl;
  68   if (OldTpl > NewTpl) {
  69     DEBUG ((EFI_D_ERROR, "FATAL ERROR - RaiseTpl with OldTpl(0x%x) > NewTpl(0x%x)\n", OldTpl, NewTpl));
  70     ASSERT (FALSE);
  71   }
  72   ASSERT (VALID_TPL (NewTpl));
  73
  74   //
  75   // If raising to high level, disable interrupts
  76   //
  77   if (NewTpl >= TPL_HIGH_LEVEL  &&  OldTpl < TPL_HIGH_LEVEL) {
  78     CoreSetInterruptState (FALSE);
  79   }
  80
  81   //
  82   // Set the new value
  83   //
  84   gEfiCurrentTpl = NewTpl;
  85
  86   return OldTpl;
  87 }
  88
  89
  90
  91
  92 /**
  93   Lowers the task priority to the previous value.   If the new
  94   priority unmasks events at a higher priority, they are dispatched.
  95
  96   @param  NewTpl  New, lower, task priority
  97
  98 **/
  99 VOID
 100 EFIAPI
 101 CoreRestoreTpl (
 102   IN EFI_TPL NewTpl
 103   )
 104 {
 105   EFI_TPL     OldTpl;
 106
 107   OldTpl = gEfiCurrentTpl;
 108   if (NewTpl > OldTpl) {
 109     DEBUG ((EFI_D_ERROR, "FATAL ERROR - RestoreTpl with NewTpl(0x%x) > OldTpl(0x%x)\n", NewTpl, OldTpl));
 110     ASSERT (FALSE);
 111   }
 112   ASSERT (VALID_TPL (NewTpl));
 113
 114   //
 115   // If lowering below HIGH_LEVEL, make sure
 116   // interrupts are enabled
 117   //
 118
 119   if (OldTpl >= TPL_HIGH_LEVEL  &&  NewTpl < TPL_HIGH_LEVEL) {
 120     gEfiCurrentTpl = TPL_HIGH_LEVEL;
 121   }
 122
 123   //
 124   // Dispatch any pending events
 125   //
 126   while (((-2 << NewTpl) & gEventPending) != 0) {
 127     gEfiCurrentTpl = (UINTN) HighBitSet64 (gEventPending);
 128     if (gEfiCurrentTpl < TPL_HIGH_LEVEL) {
 129       CoreSetInterruptState (TRUE);
 130     }
 131     CoreDispatchEventNotifies (gEfiCurrentTpl);
 132   }
 133
 134   //
 135   // Set the new value
 136   //
 137
 138   gEfiCurrentTpl = NewTpl;
 139
 140   //
 141   // If lowering below HIGH_LEVEL, make sure
 142   // interrupts are enabled
 143   //
 144   if (gEfiCurrentTpl < TPL_HIGH_LEVEL) {
 145     CoreSetInterruptState (TRUE);
 146   }
 147
 148 }