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
CoreSetInterruptState(IN BOOLEAN Enable)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
CoreRaiseTpl(IN EFI_TPL NewTpl)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
CoreRestoreTpl(IN EFI_TPL NewTpl)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 }
149