MdeModulePkg/Core/Dxe/Event/Tpl.c

   1 /** @file
   2   Task priority (TPL) functions.
   3
   4 Copyright (c) 2006 - 2018, Intel Corporation. All rights reserved.<BR>
   5 SPDX-License-Identifier: BSD-2-Clause-Patent
   6
   7 **/
   8
   9 #include "DxeMain.h"
  10 #include "Event.h"
  11
  12 /**
  13   Set Interrupt State.
  14
  15   @param  Enable  The state of enable or disable interrupt
  16
  17 **/
  18 VOID
  19 CoreSetInterruptState (
  20   IN BOOLEAN      Enable
  21   )
  22 {
  23   EFI_STATUS  Status;
  24   BOOLEAN     InSmm;
  25
  26   if (gCpu == NULL) {
  27     return;
  28   }
  29   if (!Enable) {
  30     gCpu->DisableInterrupt (gCpu);
  31     return;
  32   }
  33   if (gSmmBase2 == NULL) {
  34     gCpu->EnableInterrupt (gCpu);
  35     return;
  36   }
  37   Status = gSmmBase2->InSmm (gSmmBase2, &InSmm);
  38   if (!EFI_ERROR (Status) && !InSmm) {
  39     gCpu->EnableInterrupt(gCpu);
  40   }
  41 }
  42
  43
  44 /**
  45   Raise the task priority level to the new level.
  46   High level is implemented by disabling processor interrupts.
  47
  48   @param  NewTpl  New task priority level
  49
  50   @return The previous task priority level
  51
  52 **/
  53 EFI_TPL
  54 EFIAPI
  55 CoreRaiseTpl (
  56   IN EFI_TPL      NewTpl
  57   )
  58 {
  59   EFI_TPL     OldTpl;
  60
  61   OldTpl = gEfiCurrentTpl;
  62   if (OldTpl > NewTpl) {
  63     DEBUG ((EFI_D_ERROR, "FATAL ERROR - RaiseTpl with OldTpl(0x%x) > NewTpl(0x%x)\n", OldTpl, NewTpl));
  64     ASSERT (FALSE);
  65   }
  66   ASSERT (VALID_TPL (NewTpl));
  67
  68   //
  69   // If raising to high level, disable interrupts
  70   //
  71   if (NewTpl >= TPL_HIGH_LEVEL  &&  OldTpl < TPL_HIGH_LEVEL) {
  72     CoreSetInterruptState (FALSE);
  73   }
  74
  75   //
  76   // Set the new value
  77   //
  78   gEfiCurrentTpl = NewTpl;
  79
  80   return OldTpl;
  81 }
  82
  83
  84
  85
  86 /**
  87   Lowers the task priority to the previous value.   If the new
  88   priority unmasks events at a higher priority, they are dispatched.
  89
  90   @param  NewTpl  New, lower, task priority
  91
  92 **/
  93 VOID
  94 EFIAPI
  95 CoreRestoreTpl (
  96   IN EFI_TPL NewTpl
  97   )
  98 {
  99   EFI_TPL     OldTpl;
 100   EFI_TPL     PendingTpl;
 101
 102   OldTpl = gEfiCurrentTpl;
 103   if (NewTpl > OldTpl) {
 104     DEBUG ((EFI_D_ERROR, "FATAL ERROR - RestoreTpl with NewTpl(0x%x) > OldTpl(0x%x)\n", NewTpl, OldTpl));
 105     ASSERT (FALSE);
 106   }
 107   ASSERT (VALID_TPL (NewTpl));
 108
 109   //
 110   // If lowering below HIGH_LEVEL, make sure
 111   // interrupts are enabled
 112   //
 113
 114   if (OldTpl >= TPL_HIGH_LEVEL  &&  NewTpl < TPL_HIGH_LEVEL) {
 115     gEfiCurrentTpl = TPL_HIGH_LEVEL;
 116   }
 117
 118   //
 119   // Dispatch any pending events
 120   //
 121   while (gEventPending != 0) {
 122     PendingTpl = (UINTN) HighBitSet64 (gEventPending);
 123     if (PendingTpl <= NewTpl) {
 124       break;
 125     }
 126
 127     gEfiCurrentTpl = PendingTpl;
 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 }