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1 /** @file
2   PE/Coff Extra Action library instances.
3 
4   Copyright (c) 2010 - 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 <PeCoffExtraActionLib.h>
16 
17 /**
18   Check if the hardware breakpoint in Drx is enabled by checking the Lx and Gx bit in Dr7.
19 
20   It assumes that DebugAgent will set both Lx and Gx bit when setting up the hardware breakpoint.
21 
22 
23   @param  RegisterIndex  Index of Dr register. The value range is from 0 to 3.
24   @param  Dr7            Value of Dr7 register.
25 
26   @return TRUE   The hardware breakpoint specified in the Drx is enabled.
27   @return FALSE  The hardware breakpoint specified in the Drx is disabled.
28 
29 **/
30 BOOLEAN
IsDrxEnabled(IN UINT8 RegisterIndex,IN UINTN Dr7)31 IsDrxEnabled (
32   IN  UINT8  RegisterIndex,
33   IN  UINTN  Dr7
34   )
35 {
36   return (BOOLEAN) (((Dr7 >> (RegisterIndex * 2)) & (BIT0 | BIT1)) == (BIT0 | BIT1));
37 }
38 
39 /**
40   Common routine to report the PE/COFF image loading/relocating or unloading event.
41 
42   If ImageContext is NULL, then ASSERT().
43 
44   @param  ImageContext  Pointer to the image context structure that describes the
45                         PE/COFF image.
46   @param  Signature     IMAGE_LOAD_SIGNATURE or IMAGE_UNLOAD_SIGNATURE.
47 
48 **/
49 VOID
PeCoffLoaderExtraActionCommon(IN OUT PE_COFF_LOADER_IMAGE_CONTEXT * ImageContext,IN UINTN Signature)50 PeCoffLoaderExtraActionCommon (
51   IN OUT PE_COFF_LOADER_IMAGE_CONTEXT  *ImageContext,
52   IN     UINTN                         Signature
53   )
54 {
55   BOOLEAN                    InterruptState;
56   UINTN                      Dr0;
57   UINTN                      Dr1;
58   UINTN                      Dr2;
59   UINTN                      Dr3;
60   UINTN                      Dr7;
61   UINTN                      Cr4;
62   UINTN                      NewDr7;
63   UINT8                      LoadImageMethod;
64   UINT8                      DebugAgentStatus;
65   IA32_DESCRIPTOR            IdtDescriptor;
66   IA32_IDT_GATE_DESCRIPTOR   OriginalIdtEntry;
67   BOOLEAN                    IdtEntryHooked;
68   UINT32                     RegEdx;
69 
70   ASSERT (ImageContext != NULL);
71 
72   if (ImageContext->PdbPointer != NULL) {
73     DEBUG((EFI_D_ERROR, "    PDB = %a\n", ImageContext->PdbPointer));
74   }
75 
76   //
77   // Disable interrupts and save the current interrupt state
78   //
79   InterruptState = SaveAndDisableInterrupts ();
80 
81   IdtEntryHooked  = FALSE;
82   LoadImageMethod = PcdGet8 (PcdDebugLoadImageMethod);
83   if (LoadImageMethod == DEBUG_LOAD_IMAGE_METHOD_IO_HW_BREAKPOINT) {
84     //
85     // If the CPU does not support Debug Extensions(CPUID:01 EDX:BIT2)
86     // then force use of DEBUG_LOAD_IMAGE_METHOD_SOFT_INT3
87     //
88     AsmCpuid (1, NULL, NULL, NULL, &RegEdx);
89     if ((RegEdx & BIT2) == 0) {
90       LoadImageMethod = DEBUG_LOAD_IMAGE_METHOD_SOFT_INT3;
91     }
92   }
93   AsmReadIdtr (&IdtDescriptor);
94   if (LoadImageMethod == DEBUG_LOAD_IMAGE_METHOD_SOFT_INT3) {
95     if (!CheckDebugAgentHandler (&IdtDescriptor, SOFT_INT_VECTOR_NUM)) {
96       //
97       // Do not trigger INT3 if Debug Agent did not setup IDT entries.
98       //
99       return;
100     }
101   } else {
102     if (!CheckDebugAgentHandler (&IdtDescriptor, IO_HW_BREAKPOINT_VECTOR_NUM)) {
103       //
104       // Save and update IDT entry for INT1
105       //
106       SaveAndUpdateIdtEntry1 (&IdtDescriptor, &OriginalIdtEntry);
107       IdtEntryHooked = TRUE;
108     }
109   }
110 
111   //
112   // Save Debug Register State
113   //
114   Dr0 = AsmReadDr0 ();
115   Dr1 = AsmReadDr1 ();
116   Dr2 = AsmReadDr2 ();
117   Dr3 = AsmReadDr3 ();
118   Dr7 = AsmReadDr7 () | BIT10; // H/w sets bit 10, some simulators don't
119   Cr4 = AsmReadCr4 ();
120 
121   //
122   // DR0 = Signature
123   // DR1 = The address of the Null-terminated ASCII string for the PE/COFF image's PDB file name
124   // DR2 = The pointer to the ImageContext structure
125   // DR3 = IO_PORT_BREAKPOINT_ADDRESS
126   // DR7 = Disables all HW breakpoints except for DR3 I/O port access of length 1 byte
127   // CR4 = Make sure DE(BIT3) is set
128   //
129   AsmWriteDr7 (BIT10);
130   AsmWriteDr0 (Signature);
131   AsmWriteDr1 ((UINTN) ImageContext->PdbPointer);
132   AsmWriteDr2 ((UINTN) ImageContext);
133   AsmWriteDr3 (IO_PORT_BREAKPOINT_ADDRESS);
134 
135   if (LoadImageMethod == DEBUG_LOAD_IMAGE_METHOD_IO_HW_BREAKPOINT) {
136     AsmWriteDr7 (0x20000480);
137     AsmWriteCr4 (Cr4 | BIT3);
138     //
139     // Do an IN from IO_PORT_BREAKPOINT_ADDRESS to generate a HW breakpoint until the port
140     // returns a read value other than DEBUG_AGENT_IMAGE_WAIT
141     //
142     do {
143       DebugAgentStatus = IoRead8 (IO_PORT_BREAKPOINT_ADDRESS);
144     } while (DebugAgentStatus == DEBUG_AGENT_IMAGE_WAIT);
145 
146   } else if (LoadImageMethod == DEBUG_LOAD_IMAGE_METHOD_SOFT_INT3) {
147     //
148     // Generate a software break point.
149     //
150     CpuBreakpoint ();
151   }
152 
153   //
154   // Restore Debug Register State only when Host didn't change it inside exception handler.
155   // E.g.: User halts the target and sets the HW breakpoint while target is
156   //       in the above exception handler
157   //
158   NewDr7 = AsmReadDr7 () | BIT10; // H/w sets bit 10, some simulators don't
159   if (!IsDrxEnabled (0, NewDr7) && (AsmReadDr0 () == 0 || AsmReadDr0 () == Signature)) {
160     //
161     // If user changed Dr3 (by setting HW bp in the above exception handler,
162     // we will not set Dr0 to 0 in GO/STEP handler because the break cause is not IMAGE_LOAD/_UNLOAD.
163     //
164     AsmWriteDr0 (Dr0);
165   }
166   if (!IsDrxEnabled (1, NewDr7) && (AsmReadDr1 () == (UINTN) ImageContext->PdbPointer)) {
167     AsmWriteDr1 (Dr1);
168   }
169   if (!IsDrxEnabled (2, NewDr7) && (AsmReadDr2 () == (UINTN) ImageContext)) {
170     AsmWriteDr2 (Dr2);
171   }
172   if (!IsDrxEnabled (3, NewDr7) && (AsmReadDr3 () == IO_PORT_BREAKPOINT_ADDRESS)) {
173     AsmWriteDr3 (Dr3);
174   }
175   if (LoadImageMethod == DEBUG_LOAD_IMAGE_METHOD_IO_HW_BREAKPOINT) {
176     if (AsmReadCr4 () == (Cr4 | BIT3)) {
177       AsmWriteCr4 (Cr4);
178     }
179     if (NewDr7 == 0x20000480) {
180       AsmWriteDr7 (Dr7);
181     }
182   } else if (LoadImageMethod == DEBUG_LOAD_IMAGE_METHOD_SOFT_INT3) {
183     if (NewDr7 == BIT10) {
184       AsmWriteDr7 (Dr7);
185     }
186   }
187   //
188   // Restore original IDT entry for INT1 if it was hooked.
189   //
190   if (IdtEntryHooked) {
191     RestoreIdtEntry1 (&IdtDescriptor, &OriginalIdtEntry);
192   }
193   //
194   // Restore the interrupt state
195   //
196   SetInterruptState (InterruptState);
197 }
198 
199 /**
200   Performs additional actions after a PE/COFF image has been loaded and relocated.
201 
202   @param  ImageContext  Pointer to the image context structure that describes the
203                         PE/COFF image that has already been loaded and relocated.
204 
205 **/
206 VOID
207 EFIAPI
PeCoffLoaderRelocateImageExtraAction(IN OUT PE_COFF_LOADER_IMAGE_CONTEXT * ImageContext)208 PeCoffLoaderRelocateImageExtraAction (
209   IN OUT PE_COFF_LOADER_IMAGE_CONTEXT  *ImageContext
210   )
211 {
212   PeCoffLoaderExtraActionCommon (ImageContext, IMAGE_LOAD_SIGNATURE);
213 }
214 
215 /**
216   Performs additional actions just before a PE/COFF image is unloaded.  Any resources
217   that were allocated by PeCoffLoaderRelocateImageExtraAction() must be freed.
218 
219   @param  ImageContext  Pointer to the image context structure that describes the
220                         PE/COFF image that is being unloaded.
221 
222 **/
223 VOID
224 EFIAPI
PeCoffLoaderUnloadImageExtraAction(IN OUT PE_COFF_LOADER_IMAGE_CONTEXT * ImageContext)225 PeCoffLoaderUnloadImageExtraAction (
226   IN OUT PE_COFF_LOADER_IMAGE_CONTEXT  *ImageContext
227   )
228 {
229   PeCoffLoaderExtraActionCommon (ImageContext, IMAGE_UNLOAD_SIGNATURE);
230 }
231