--- /dev/null
+/** @file\r
+ Call into 16-bit BIOS code, Use AsmThunk16 function of BaseLib.\r
+\r
+Copyright (c) 2006 - 2018, Intel Corporation. All rights reserved.<BR>\r
+\r
+SPDX-License-Identifier: BSD-2-Clause-Patent\r
+\r
+**/\r
+\r
+#include "LegacyBiosInterface.h"\r
+\r
+THUNK_CONTEXT mThunkContext;\r
+\r
+/**\r
+ Sets the counter value for Timer #0 in a legacy 8254 timer.\r
+\r
+ @param Count - The 16-bit counter value to program into Timer #0 of the legacy 8254 timer.\r
+\r
+**/\r
+VOID\r
+SetPitCount (\r
+ IN UINT16 Count\r
+ )\r
+{\r
+ IoWrite8 (TIMER_CONTROL_PORT, TIMER0_CONTROL_WORD);\r
+ IoWrite8 (TIMER0_COUNT_PORT, (UINT8) (Count & 0xFF));\r
+ IoWrite8 (TIMER0_COUNT_PORT, (UINT8) ((Count>>8) & 0xFF));\r
+}\r
+\r
+/**\r
+ Thunk to 16-bit real mode and execute a software interrupt with a vector\r
+ of BiosInt. Regs will contain the 16-bit register context on entry and\r
+ exit.\r
+\r
+ @param This Protocol instance pointer.\r
+ @param BiosInt Processor interrupt vector to invoke\r
+ @param Regs Register contexted passed into (and returned) from thunk to\r
+ 16-bit mode\r
+\r
+ @retval FALSE Thunk completed, and there were no BIOS errors in the target code.\r
+ See Regs for status.\r
+ @retval TRUE There was a BIOS erro in the target code.\r
+\r
+**/\r
+BOOLEAN\r
+EFIAPI\r
+LegacyBiosInt86 (\r
+ IN EFI_LEGACY_BIOS_PROTOCOL *This,\r
+ IN UINT8 BiosInt,\r
+ IN EFI_IA32_REGISTER_SET *Regs\r
+ )\r
+{\r
+ UINT16 Segment;\r
+ UINT16 Offset;\r
+\r
+ Regs->X.Flags.Reserved1 = 1;\r
+ Regs->X.Flags.Reserved2 = 0;\r
+ Regs->X.Flags.Reserved3 = 0;\r
+ Regs->X.Flags.Reserved4 = 0;\r
+ Regs->X.Flags.IOPL = 3;\r
+ Regs->X.Flags.NT = 0;\r
+ Regs->X.Flags.IF = 0;\r
+ Regs->X.Flags.TF = 0;\r
+ Regs->X.Flags.CF = 0;\r
+ //\r
+ // The base address of legacy interrupt vector table is 0.\r
+ // We use this base address to get the legacy interrupt handler.\r
+ //\r
+ ACCESS_PAGE0_CODE (\r
+ Segment = (UINT16)(((UINT32 *)0)[BiosInt] >> 16);\r
+ Offset = (UINT16)((UINT32 *)0)[BiosInt];\r
+ );\r
+\r
+ return InternalLegacyBiosFarCall (\r
+ This,\r
+ Segment,\r
+ Offset,\r
+ Regs,\r
+ &Regs->X.Flags,\r
+ sizeof (Regs->X.Flags)\r
+ );\r
+}\r
+\r
+/**\r
+ Thunk to 16-bit real mode and call Segment:Offset. Regs will contain the\r
+ 16-bit register context on entry and exit. Arguments can be passed on\r
+ the Stack argument\r
+\r
+ @param This Protocol instance pointer.\r
+ @param Segment Segemnt of 16-bit mode call\r
+ @param Offset Offset of 16-bit mdoe call\r
+ @param Regs Register contexted passed into (and returned) from\r
+ thunk to 16-bit mode\r
+ @param Stack Caller allocated stack used to pass arguments\r
+ @param StackSize Size of Stack in bytes\r
+\r
+ @retval FALSE Thunk completed, and there were no BIOS errors in\r
+ the target code. See Regs for status.\r
+ @retval TRUE There was a BIOS erro in the target code.\r
+\r
+**/\r
+BOOLEAN\r
+EFIAPI\r
+LegacyBiosFarCall86 (\r
+ IN EFI_LEGACY_BIOS_PROTOCOL *This,\r
+ IN UINT16 Segment,\r
+ IN UINT16 Offset,\r
+ IN EFI_IA32_REGISTER_SET *Regs,\r
+ IN VOID *Stack,\r
+ IN UINTN StackSize\r
+ )\r
+{\r
+ Regs->X.Flags.Reserved1 = 1;\r
+ Regs->X.Flags.Reserved2 = 0;\r
+ Regs->X.Flags.Reserved3 = 0;\r
+ Regs->X.Flags.Reserved4 = 0;\r
+ Regs->X.Flags.IOPL = 3;\r
+ Regs->X.Flags.NT = 0;\r
+ Regs->X.Flags.IF = 1;\r
+ Regs->X.Flags.TF = 0;\r
+ Regs->X.Flags.CF = 0;\r
+\r
+ return InternalLegacyBiosFarCall (This, Segment, Offset, Regs, Stack, StackSize);\r
+}\r
+\r
+/**\r
+ Provide NULL interrupt handler which is used to check\r
+ if there is more than one HW interrupt registers with the CPU AP.\r
+\r
+ @param InterruptType - The type of interrupt that occured\r
+ @param SystemContext - A pointer to the system context when the interrupt occured\r
+\r
+**/\r
+VOID\r
+EFIAPI\r
+LegacyBiosNullInterruptHandler (\r
+ IN EFI_EXCEPTION_TYPE InterruptType,\r
+ IN EFI_SYSTEM_CONTEXT SystemContext\r
+ )\r
+{\r
+}\r
+\r
+/**\r
+ Thunk to 16-bit real mode and call Segment:Offset. Regs will contain the\r
+ 16-bit register context on entry and exit. Arguments can be passed on\r
+ the Stack argument\r
+\r
+ @param This Protocol instance pointer.\r
+ @param Segment Segemnt of 16-bit mode call\r
+ @param Offset Offset of 16-bit mdoe call\r
+ @param Regs Register contexted passed into (and returned) from thunk to\r
+ 16-bit mode\r
+ @param Stack Caller allocated stack used to pass arguments\r
+ @param StackSize Size of Stack in bytes\r
+\r
+ @retval FALSE Thunk completed, and there were no BIOS errors in the target code.\r
+ See Regs for status.\r
+ @retval TRUE There was a BIOS erro in the target code.\r
+\r
+**/\r
+BOOLEAN\r
+EFIAPI\r
+InternalLegacyBiosFarCall (\r
+ IN EFI_LEGACY_BIOS_PROTOCOL *This,\r
+ IN UINT16 Segment,\r
+ IN UINT16 Offset,\r
+ IN EFI_IA32_REGISTER_SET *Regs,\r
+ IN VOID *Stack,\r
+ IN UINTN StackSize\r
+ )\r
+{\r
+ UINTN Status;\r
+ LEGACY_BIOS_INSTANCE *Private;\r
+ UINT16 *Stack16;\r
+ EFI_TPL OriginalTpl;\r
+ IA32_REGISTER_SET ThunkRegSet;\r
+ BOOLEAN InterruptState;\r
+ UINT64 TimerPeriod;\r
+\r
+ Private = LEGACY_BIOS_INSTANCE_FROM_THIS (This);\r
+\r
+ ZeroMem (&ThunkRegSet, sizeof (ThunkRegSet));\r
+ ThunkRegSet.X.DI = Regs->X.DI;\r
+ ThunkRegSet.X.SI = Regs->X.SI;\r
+ ThunkRegSet.X.BP = Regs->X.BP;\r
+ ThunkRegSet.X.BX = Regs->X.BX;\r
+ ThunkRegSet.X.DX = Regs->X.DX;\r
+ //\r
+ // Sometimes, ECX is used to pass in 32 bit data. For example, INT 1Ah, AX = B10Dh is\r
+ // "PCI BIOS v2.0c + Write Configuration DWORD" and ECX has the dword to write.\r
+ //\r
+ ThunkRegSet.E.ECX = Regs->E.ECX;\r
+ ThunkRegSet.X.AX = Regs->X.AX;\r
+ ThunkRegSet.E.DS = Regs->X.DS;\r
+ ThunkRegSet.E.ES = Regs->X.ES;\r
+\r
+ CopyMem (&(ThunkRegSet.E.EFLAGS.UintN), &(Regs->X.Flags), sizeof (Regs->X.Flags));\r
+\r
+ //\r
+ // Clear the error flag; thunk code may set it. Stack16 should be the high address\r
+ // Make Statk16 address the low 16 bit must be not zero.\r
+ //\r
+ Stack16 = (UINT16 *)((UINT8 *) mThunkContext.RealModeBuffer + mThunkContext.RealModeBufferSize - sizeof (UINT16));\r
+\r
+ //\r
+ // Save current rate of DXE Timer\r
+ //\r
+ Private->Timer->GetTimerPeriod (Private->Timer, &TimerPeriod);\r
+\r
+ //\r
+ // Disable DXE Timer while executing in real mode\r
+ //\r
+ Private->Timer->SetTimerPeriod (Private->Timer, 0);\r
+\r
+ //\r
+ // Save and disable interrupt of debug timer\r
+ //\r
+ InterruptState = SaveAndSetDebugTimerInterrupt (FALSE);\r
+\r
+ //\r
+ // The call to Legacy16 is a critical section to EFI\r
+ //\r
+ OriginalTpl = gBS->RaiseTPL (TPL_HIGH_LEVEL);\r
+\r
+ //\r
+ // Check to see if there is more than one HW interrupt registers with the CPU AP.\r
+ // If there is, then ASSERT() since that is not compatible with the CSM because\r
+ // interupts other than the Timer interrupt that was disabled above can not be\r
+ // handled properly from real mode.\r
+ //\r
+ DEBUG_CODE (\r
+ UINTN Vector;\r
+ UINTN Count;\r
+\r
+ for (Vector = 0x20, Count = 0; Vector < 0x100; Vector++) {\r
+ Status = Private->Cpu->RegisterInterruptHandler (Private->Cpu, Vector, LegacyBiosNullInterruptHandler);\r
+ if (Status == EFI_ALREADY_STARTED) {\r
+ Count++;\r
+ }\r
+ if (Status == EFI_SUCCESS) {\r
+ Private->Cpu->RegisterInterruptHandler (Private->Cpu, Vector, NULL);\r
+ }\r
+ }\r
+ if (Count >= 2) {\r
+ DEBUG ((EFI_D_ERROR, "ERROR: More than one HW interrupt active with CSM enabled\n"));\r
+ }\r
+ ASSERT (Count < 2);\r
+ );\r
+\r
+ //\r
+ // If the Timer AP has enabled the 8254 timer IRQ and the current 8254 timer\r
+ // period is less than the CSM required rate of 54.9254, then force the 8254\r
+ // PIT counter to 0, which is the CSM required rate of 54.9254 ms\r
+ //\r
+ if (Private->TimerUses8254 && TimerPeriod < 549254) {\r
+ SetPitCount (0);\r
+ }\r
+\r
+ if (Stack != NULL && StackSize != 0) {\r
+ //\r
+ // Copy Stack to low memory stack\r
+ //\r
+ Stack16 -= StackSize / sizeof (UINT16);\r
+ CopyMem (Stack16, Stack, StackSize);\r
+ }\r
+\r
+ ThunkRegSet.E.SS = (UINT16) (((UINTN) Stack16 >> 16) << 12);\r
+ ThunkRegSet.E.ESP = (UINT16) (UINTN) Stack16;\r
+ ThunkRegSet.E.CS = Segment;\r
+ ThunkRegSet.E.Eip = Offset;\r
+\r
+ mThunkContext.RealModeState = &ThunkRegSet;\r
+\r
+ //\r
+ // Set Legacy16 state. 0x08, 0x70 is legacy 8259 vector bases.\r
+ //\r
+ Status = Private->Legacy8259->SetMode (Private->Legacy8259, Efi8259LegacyMode, NULL, NULL);\r
+ ASSERT_EFI_ERROR (Status);\r
+\r
+ AsmThunk16 (&mThunkContext);\r
+\r
+ if (Stack != NULL && StackSize != 0) {\r
+ //\r
+ // Copy low memory stack to Stack\r
+ //\r
+ CopyMem (Stack, Stack16, StackSize);\r
+ }\r
+\r
+ //\r
+ // Restore protected mode interrupt state\r
+ //\r
+ Status = Private->Legacy8259->SetMode (Private->Legacy8259, Efi8259ProtectedMode, NULL, NULL);\r
+ ASSERT_EFI_ERROR (Status);\r
+\r
+ mThunkContext.RealModeState = NULL;\r
+\r
+ //\r
+ // Enable and restore rate of DXE Timer\r
+ //\r
+ Private->Timer->SetTimerPeriod (Private->Timer, TimerPeriod);\r
+\r
+ //\r
+ // End critical section\r
+ //\r
+ gBS->RestoreTPL (OriginalTpl);\r
+\r
+ //\r
+ // OPROM may allocate EBDA range by itself and change EBDA base and EBDA size.\r
+ // Get the current EBDA base address, and compared with pre-allocate minimum\r
+ // EBDA base address, if the current EBDA base address is smaller, it indicates\r
+ // PcdEbdaReservedMemorySize should be adjusted to larger for more OPROMs.\r
+ //\r
+ DEBUG_CODE (\r
+ {\r
+ UINTN EbdaBaseAddress;\r
+ UINTN ReservedEbdaBaseAddress;\r
+\r
+ ACCESS_PAGE0_CODE (\r
+ EbdaBaseAddress = (*(UINT16 *) (UINTN) 0x40E) << 4;\r
+ ReservedEbdaBaseAddress = CONVENTIONAL_MEMORY_TOP\r
+ - PcdGet32 (PcdEbdaReservedMemorySize);\r
+ ASSERT (ReservedEbdaBaseAddress <= EbdaBaseAddress);\r
+ );\r
+ }\r
+ );\r
+\r
+ //\r
+ // Restore interrupt of debug timer\r
+ //\r
+ SaveAndSetDebugTimerInterrupt (InterruptState);\r
+\r
+ Regs->E.EDI = ThunkRegSet.E.EDI;\r
+ Regs->E.ESI = ThunkRegSet.E.ESI;\r
+ Regs->E.EBP = ThunkRegSet.E.EBP;\r
+ Regs->E.EBX = ThunkRegSet.E.EBX;\r
+ Regs->E.EDX = ThunkRegSet.E.EDX;\r
+ Regs->E.ECX = ThunkRegSet.E.ECX;\r
+ Regs->E.EAX = ThunkRegSet.E.EAX;\r
+ Regs->X.SS = ThunkRegSet.E.SS;\r
+ Regs->X.CS = ThunkRegSet.E.CS;\r
+ Regs->X.DS = ThunkRegSet.E.DS;\r
+ Regs->X.ES = ThunkRegSet.E.ES;\r
+\r
+ CopyMem (&(Regs->X.Flags), &(ThunkRegSet.E.EFLAGS.UintN), sizeof (Regs->X.Flags));\r
+\r
+ return (BOOLEAN) (Regs->X.Flags.CF == 1);\r
+}\r
+\r
+/**\r
+ Allocate memory < 1 MB and copy the thunker code into low memory. Se up\r
+ all the descriptors.\r
+\r
+ @param Private Private context for Legacy BIOS\r
+\r
+ @retval EFI_SUCCESS Should only pass.\r
+\r
+**/\r
+EFI_STATUS\r
+LegacyBiosInitializeThunk (\r
+ IN LEGACY_BIOS_INSTANCE *Private\r
+ )\r
+{\r
+ EFI_STATUS Status;\r
+ EFI_PHYSICAL_ADDRESS MemoryAddress;\r
+ UINT8 TimerVector;\r
+\r
+ MemoryAddress = (EFI_PHYSICAL_ADDRESS) (UINTN) Private->IntThunk;\r
+\r
+ mThunkContext.RealModeBuffer = (VOID *) (UINTN) (MemoryAddress + ((sizeof (LOW_MEMORY_THUNK) / EFI_PAGE_SIZE) + 1) * EFI_PAGE_SIZE);\r
+ mThunkContext.RealModeBufferSize = EFI_PAGE_SIZE;\r
+ mThunkContext.ThunkAttributes = THUNK_ATTRIBUTE_BIG_REAL_MODE | THUNK_ATTRIBUTE_DISABLE_A20_MASK_INT_15;\r
+\r
+ AsmPrepareThunk16 (&mThunkContext);\r
+\r
+ //\r
+ // Get the interrupt vector number corresponding to IRQ0 from the 8259 driver\r
+ //\r
+ TimerVector = 0;\r
+ Status = Private->Legacy8259->GetVector (Private->Legacy8259, Efi8259Irq0, &TimerVector);\r
+ ASSERT_EFI_ERROR (Status);\r
+\r
+ //\r
+ // Check to see if the Timer AP has hooked the IRQ0 from the 8254 PIT\r
+ //\r
+ Status = Private->Cpu->RegisterInterruptHandler (\r
+ Private->Cpu,\r
+ TimerVector,\r
+ LegacyBiosNullInterruptHandler\r
+ );\r
+ if (Status == EFI_SUCCESS) {\r
+ //\r
+ // If the Timer AP has not enabled the 8254 timer IRQ, then force the 8254 PIT\r
+ // counter to 0, which is the CSM required rate of 54.9254 ms\r
+ //\r
+ Private->Cpu->RegisterInterruptHandler (\r
+ Private->Cpu,\r
+ TimerVector,\r
+ NULL\r
+ );\r
+ SetPitCount (0);\r
+\r
+ //\r
+ // Save status that the Timer AP is not using the 8254 PIT\r
+ //\r
+ Private->TimerUses8254 = FALSE;\r
+ } else if (Status == EFI_ALREADY_STARTED) {\r
+ //\r
+ // Save status that the Timer AP is using the 8254 PIT\r
+ //\r
+ Private->TimerUses8254 = TRUE;\r
+ } else {\r
+ //\r
+ // Unexpected status from CPU AP RegisterInterruptHandler()\r
+ //\r
+ ASSERT (FALSE);\r
+ }\r
+\r
+ return EFI_SUCCESS;\r
+}\r
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