1 /** @file 2 IA32/x64 generic functions to support Debug Support protocol. 3 4 Copyright (c) 2006 - 2010, 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 "DebugSupport.h" 16 17 // 18 // This the global main table to keep track of the interrupts 19 // 20 IDT_ENTRY *IdtEntryTable = NULL; 21 22 /** 23 Read IDT Gate Descriptor from IDT Table. 24 25 @param Vector Specifies vector number. 26 @param IdtGateDescriptor Pointer to IDT Gate Descriptor read from IDT Table. 27 28 **/ 29 VOID 30 ReadIdtGateDescriptor ( 31 IN EFI_EXCEPTION_TYPE Vector, 32 OUT IA32_IDT_GATE_DESCRIPTOR *IdtGateDescriptor 33 ) 34 { 35 IA32_DESCRIPTOR IdtrValue; 36 IA32_IDT_GATE_DESCRIPTOR *IdtTable; 37 38 AsmReadIdtr (&IdtrValue); 39 IdtTable = (IA32_IDT_GATE_DESCRIPTOR *) IdtrValue.Base; 40 41 CopyMem ((VOID *) IdtGateDescriptor, (VOID *) &(IdtTable)[Vector], sizeof (IA32_IDT_GATE_DESCRIPTOR)); 42 } 43 44 /** 45 Write IDT Gate Descriptor into IDT Table. 46 47 @param Vector Specifies vector number. 48 @param IdtGateDescriptor Pointer to IDT Gate Descriptor written into IDT Table. 49 50 **/ 51 VOID 52 WriteIdtGateDescriptor ( 53 EFI_EXCEPTION_TYPE Vector, 54 IA32_IDT_GATE_DESCRIPTOR *IdtGateDescriptor 55 ) 56 { 57 IA32_DESCRIPTOR IdtrValue; 58 IA32_IDT_GATE_DESCRIPTOR *IdtTable; 59 60 AsmReadIdtr (&IdtrValue); 61 IdtTable = (IA32_IDT_GATE_DESCRIPTOR *) IdtrValue.Base; 62 63 CopyMem ((VOID *) &(IdtTable)[Vector], (VOID *) IdtGateDescriptor, sizeof (IA32_IDT_GATE_DESCRIPTOR)); 64 } 65 66 /** 67 Creates a nes entry stub. Then saves the current IDT entry and replaces it 68 with an interrupt gate for the new entry point. The IdtEntryTable is updated 69 with the new registered function. 70 71 This code executes in boot services context. The stub entry executes in interrupt 72 context. 73 74 @param ExceptionType Specifies which vector to hook. 75 @param NewCallback A pointer to the new function to be registered. 76 77 **/ 78 VOID 79 HookEntry ( 80 IN EFI_EXCEPTION_TYPE ExceptionType, 81 IN CALLBACK_FUNC NewCallback 82 ) 83 { 84 BOOLEAN OldIntFlagState; 85 86 CreateEntryStub (ExceptionType, (VOID **) &IdtEntryTable[ExceptionType].StubEntry); 87 88 // 89 // Disables CPU interrupts and returns the previous interrupt state 90 // 91 OldIntFlagState = SaveAndDisableInterrupts (); 92 93 // 94 // gets IDT Gate descriptor by index 95 // 96 ReadIdtGateDescriptor (ExceptionType, &(IdtEntryTable[ExceptionType].OrigDesc)); 97 // 98 // stores orignal interrupt handle 99 // 100 IdtEntryTable[ExceptionType].OrigVector = (DEBUG_PROC) GetInterruptHandleFromIdt (&(IdtEntryTable[ExceptionType].OrigDesc)); 101 102 // 103 // encodes new IDT Gate descriptor by stub entry 104 // 105 Vect2Desc (&IdtEntryTable[ExceptionType].NewDesc, IdtEntryTable[ExceptionType].StubEntry); 106 // 107 // stores NewCallback 108 // 109 IdtEntryTable[ExceptionType].RegisteredCallback = NewCallback; 110 111 // 112 // writes back new IDT Gate descriptor 113 // 114 WriteIdtGateDescriptor (ExceptionType, &(IdtEntryTable[ExceptionType].NewDesc)); 115 116 // 117 // restore interrupt state 118 // 119 SetInterruptState (OldIntFlagState); 120 121 return ; 122 } 123 124 /** 125 Undoes HookEntry. This code executes in boot services context. 126 127 @param ExceptionType Specifies which entry to unhook 128 129 **/ 130 VOID 131 UnhookEntry ( 132 IN EFI_EXCEPTION_TYPE ExceptionType 133 ) 134 { 135 BOOLEAN OldIntFlagState; 136 137 // 138 // Disables CPU interrupts and returns the previous interrupt state 139 // 140 OldIntFlagState = SaveAndDisableInterrupts (); 141 142 // 143 // restore the default IDT Date Descriptor 144 // 145 WriteIdtGateDescriptor (ExceptionType, &(IdtEntryTable[ExceptionType].OrigDesc)); 146 147 // 148 // restore interrupt state 149 // 150 SetInterruptState (OldIntFlagState); 151 152 return ; 153 } 154 155 /** 156 Returns the maximum value that may be used for the ProcessorIndex parameter in 157 RegisterPeriodicCallback() and RegisterExceptionCallback(). 158 159 Hard coded to support only 1 processor for now. 160 161 @param This A pointer to the EFI_DEBUG_SUPPORT_PROTOCOL instance. 162 @param MaxProcessorIndex Pointer to a caller-allocated UINTN in which the maximum supported 163 processor index is returned. Always 0 returned. 164 165 @retval EFI_SUCCESS Always returned with **MaxProcessorIndex set to 0. 166 167 **/ 168 EFI_STATUS 169 EFIAPI 170 GetMaximumProcessorIndex ( 171 IN EFI_DEBUG_SUPPORT_PROTOCOL *This, 172 OUT UINTN *MaxProcessorIndex 173 ) 174 { 175 *MaxProcessorIndex = 0; 176 return EFI_SUCCESS; 177 } 178 179 /** 180 Registers a function to be called back periodically in interrupt context. 181 182 @param This A pointer to the EFI_DEBUG_SUPPORT_PROTOCOL instance. 183 @param ProcessorIndex Specifies which processor the callback function applies to. 184 @param PeriodicCallback A pointer to a function of type PERIODIC_CALLBACK that is the main 185 periodic entry point of the debug agent. 186 187 @retval EFI_SUCCESS The function completed successfully. 188 @retval EFI_ALREADY_STARTED Non-NULL PeriodicCallback parameter when a callback 189 function was previously registered. 190 @retval EFI_OUT_OF_RESOURCES System has insufficient memory resources to register new callback 191 function. 192 **/ 193 EFI_STATUS 194 EFIAPI 195 RegisterPeriodicCallback ( 196 IN EFI_DEBUG_SUPPORT_PROTOCOL *This, 197 IN UINTN ProcessorIndex, 198 IN EFI_PERIODIC_CALLBACK PeriodicCallback 199 ) 200 { 201 return ManageIdtEntryTable (PeriodicCallback, SYSTEM_TIMER_VECTOR); 202 } 203 204 /** 205 Registers a function to be called when a given processor exception occurs. 206 207 This code executes in boot services context. 208 209 @param This A pointer to the EFI_DEBUG_SUPPORT_PROTOCOL instance. 210 @param ProcessorIndex Specifies which processor the callback function applies to. 211 @param ExceptionCallback A pointer to a function of type EXCEPTION_CALLBACK that is called 212 when the processor exception specified by ExceptionType occurs. 213 @param ExceptionType Specifies which processor exception to hook. 214 215 @retval EFI_SUCCESS The function completed successfully. 216 @retval EFI_ALREADY_STARTED Non-NULL PeriodicCallback parameter when a callback 217 function was previously registered. 218 @retval EFI_OUT_OF_RESOURCES System has insufficient memory resources to register new callback 219 function. 220 **/ 221 EFI_STATUS 222 EFIAPI 223 RegisterExceptionCallback ( 224 IN EFI_DEBUG_SUPPORT_PROTOCOL *This, 225 IN UINTN ProcessorIndex, 226 IN EFI_EXCEPTION_CALLBACK ExceptionCallback, 227 IN EFI_EXCEPTION_TYPE ExceptionType 228 ) 229 { 230 return ManageIdtEntryTable (ExceptionCallback, ExceptionType); 231 } 232 233 234 /** 235 Invalidates processor instruction cache for a memory range. Subsequent execution in this range 236 causes a fresh memory fetch to retrieve code to be executed. 237 238 @param This A pointer to the EFI_DEBUG_SUPPORT_PROTOCOL instance. 239 @param ProcessorIndex Specifies which processor's instruction cache is to be invalidated. 240 @param Start Specifies the physical base of the memory range to be invalidated. 241 @param Length Specifies the minimum number of bytes in the processor's instruction 242 cache to invalidate. 243 244 @retval EFI_SUCCESS Always returned. 245 246 **/ 247 EFI_STATUS 248 EFIAPI 249 InvalidateInstructionCache ( 250 IN EFI_DEBUG_SUPPORT_PROTOCOL *This, 251 IN UINTN ProcessorIndex, 252 IN VOID *Start, 253 IN UINT64 Length 254 ) 255 { 256 AsmWbinvd (); 257 return EFI_SUCCESS; 258 } 259 260 /** 261 Common piece of code that invokes the registered handlers. 262 263 This code executes in exception context so no efi calls are allowed. 264 This code is called from assembly file. 265 266 @param ExceptionType Exception type 267 @param ContextRecord System context 268 269 **/ 270 VOID 271 InterruptDistrubutionHub ( 272 EFI_EXCEPTION_TYPE ExceptionType, 273 EFI_SYSTEM_CONTEXT_IA32 *ContextRecord 274 ) 275 { 276 if (IdtEntryTable[ExceptionType].RegisteredCallback != NULL) { 277 if (ExceptionType != SYSTEM_TIMER_VECTOR) { 278 IdtEntryTable[ExceptionType].RegisteredCallback (ExceptionType, ContextRecord); 279 } else { 280 OrigVector = IdtEntryTable[ExceptionType].OrigVector; 281 IdtEntryTable[ExceptionType].RegisteredCallback (ContextRecord); 282 } 283 } 284 } 285 286 /** 287 This is the callback that is written to the Loaded Image protocol instance 288 on the image handle. It uninstalls all registered handlers and frees all entry 289 stub memory. 290 291 @param ImageHandle The firmware allocated handle for the EFI image. 292 293 @retval EFI_SUCCESS Always. 294 295 **/ 296 EFI_STATUS 297 EFIAPI 298 PlUnloadDebugSupportDriver ( 299 IN EFI_HANDLE ImageHandle 300 ) 301 { 302 EFI_EXCEPTION_TYPE ExceptionType; 303 304 for (ExceptionType = 0; ExceptionType < NUM_IDT_ENTRIES; ExceptionType++) { 305 ManageIdtEntryTable (NULL, ExceptionType); 306 // 307 // Free space for each Interrupt Stub precedure. 308 // 309 if (IdtEntryTable[ExceptionType].StubEntry != NULL) { 310 FreePool ((VOID *)(UINTN)IdtEntryTable[ExceptionType].StubEntry); 311 } 312 } 313 314 FreePool (IdtEntryTable); 315 316 return EFI_SUCCESS; 317 } 318 319 /** 320 Initializes driver's handler registration database. 321 322 This code executes in boot services context. 323 Must be public because it's referenced from DebugSupport.c 324 325 @retval EFI_UNSUPPORTED If IA32/x64 processor does not support FXSTOR/FXRSTOR instructions, 326 the context save will fail, so these processors are not supported. 327 @retval EFI_OUT_OF_RESOURCES Fails to allocate memory. 328 @retval EFI_SUCCESS Initializes successfully. 329 330 **/ 331 EFI_STATUS 332 PlInitializeDebugSupportDriver ( 333 VOID 334 ) 335 { 336 EFI_EXCEPTION_TYPE ExceptionType; 337 338 // 339 // Check whether FxStor instructions are supported. 340 // 341 if (!FxStorSupport ()) { 342 return EFI_UNSUPPORTED; 343 } 344 345 IdtEntryTable = AllocateZeroPool (sizeof (IDT_ENTRY) * NUM_IDT_ENTRIES); 346 if (IdtEntryTable == NULL) { 347 return EFI_OUT_OF_RESOURCES; 348 } 349 350 for (ExceptionType = 0; ExceptionType < NUM_IDT_ENTRIES; ExceptionType ++) { 351 IdtEntryTable[ExceptionType].StubEntry = (DEBUG_PROC) (UINTN) AllocatePool (StubSize); 352 if (IdtEntryTable[ExceptionType].StubEntry == NULL) { 353 goto ErrorCleanup; 354 } 355 356 // 357 // Copy Interrupt stub code. 358 // 359 CopyMem ((VOID *)(UINTN)IdtEntryTable[ExceptionType].StubEntry, InterruptEntryStub, StubSize); 360 } 361 return EFI_SUCCESS; 362 363 ErrorCleanup: 364 365 for (ExceptionType = 0; ExceptionType < NUM_IDT_ENTRIES; ExceptionType++) { 366 if (IdtEntryTable[ExceptionType].StubEntry != NULL) { 367 FreePool ((VOID *)(UINTN)IdtEntryTable[ExceptionType].StubEntry); 368 } 369 } 370 FreePool (IdtEntryTable); 371 372 return EFI_OUT_OF_RESOURCES; 373 } 374