24 Jan
2022
24 Jan
'22
11:17 p.m.
https://git.reactos.org/?p=reactos.git;a=commitdiff;h=99a6667bd911ad7dec92b…
commit 99a6667bd911ad7dec92bfacdfa10cb702b37793
Author: Victor Perevertkin <victor.perevertkin(a)reactos.org>
AuthorDate: Sat Jan 15 04:15:05 2022 +0300
Commit: Victor Perevertkin <victor.perevertkin(a)reactos.org>
CommitDate: Tue Jan 25 02:12:33 2022 +0300
[NTOS:KE] Remove all checks for x87 not being present
---
ntoskrnl/ke/i386/cpu.c | 140 +++++---------------------
ntoskrnl/ke/i386/exp.c | 245 ++++++++++++++++++---------------------------
ntoskrnl/ke/i386/kiinit.c | 68 +++----------
ntoskrnl/ke/i386/thrdini.c | 33 ++----
4 files changed, 151 insertions(+), 335 deletions(-)
diff --git a/ntoskrnl/ke/i386/cpu.c b/ntoskrnl/ke/i386/cpu.c
index 03bd33d465b..e627efe228a 100644
--- a/ntoskrnl/ke/i386/cpu.c
+++ b/ntoskrnl/ke/i386/cpu.c
@@ -24,7 +24,7 @@ UCHAR KiNMITSS[KTSS_IO_MAPS];
ULONG KeI386CpuType;
ULONG KeI386CpuStep;
ULONG KiFastSystemCallDisable = 0;
-ULONG KeI386NpxPresent = 0;
+ULONG KeI386NpxPresent = TRUE;
ULONG KiMXCsrMask = 0;
ULONG MxcsrFeatureMask = 0;
ULONG KeI386XMMIPresent = 0;
@@ -90,66 +90,30 @@ VOID
NTAPI
KiSetProcessorType(VOID)
{
- ULONG EFlags, NewEFlags;
CPU_INFO CpuInfo;
ULONG Stepping, Type;
- /* Start by assuming no CPUID data */
- KeGetCurrentPrcb()->CpuID = 0;
-
- /* Save EFlags */
- EFlags = __readeflags();
-
- /* XOR out the ID bit and update EFlags */
- NewEFlags = EFlags ^ EFLAGS_ID;
- __writeeflags(NewEFlags);
-
- /* Get them back and see if they were modified */
- NewEFlags = __readeflags();
- if (NewEFlags != EFlags)
- {
- /* The modification worked, so CPUID exists. Set the ID Bit again. */
- EFlags |= EFLAGS_ID;
- __writeeflags(EFlags);
-
- /* Peform CPUID 0 to see if CPUID 1 is supported */
- KiCpuId(&CpuInfo, 0);
- if (CpuInfo.Eax > 0)
- {
- /* Do CPUID 1 now */
- KiCpuId(&CpuInfo, 1);
-
- /*
- * Get the Stepping and Type. The stepping contains both the
- * Model and the Step, while the Type contains the returned Type.
- * We ignore the family.
- *
- * For the stepping, we convert this: zzzzzzxy into this: x0y
- */
- Stepping = CpuInfo.Eax & 0xF0;
- Stepping <<= 4;
- Stepping += (CpuInfo.Eax & 0xFF);
- Stepping &= 0xF0F;
- Type = CpuInfo.Eax & 0xF00;
- Type >>= 8;
-
- /* Save them in the PRCB */
- KeGetCurrentPrcb()->CpuID = TRUE;
- KeGetCurrentPrcb()->CpuType = (UCHAR)Type;
- KeGetCurrentPrcb()->CpuStep = (USHORT)Stepping;
- }
- else
- {
- DPRINT1("CPUID Support lacking\n");
- }
- }
- else
- {
- DPRINT1("CPUID Support lacking\n");
- }
+ /* Do CPUID 1 now */
+ KiCpuId(&CpuInfo, 1);
- /* Restore EFLAGS */
- __writeeflags(EFlags);
+ /*
+ * Get the Stepping and Type. The stepping contains both the
+ * Model and the Step, while the Type contains the returned Type.
+ * We ignore the family.
+ *
+ * For the stepping, we convert this: zzzzzzxy into this: x0y
+ */
+ Stepping = CpuInfo.Eax & 0xF0;
+ Stepping <<= 4;
+ Stepping += (CpuInfo.Eax & 0xFF);
+ Stepping &= 0xF0F;
+ Type = CpuInfo.Eax & 0xF00;
+ Type >>= 8;
+
+ /* Save them in the PRCB */
+ KeGetCurrentPrcb()->CpuID = TRUE;
+ KeGetCurrentPrcb()->CpuType = (UCHAR)Type;
+ KeGetCurrentPrcb()->CpuStep = (USHORT)Stepping;
}
CODE_SEG("INIT")
@@ -160,10 +124,6 @@ KiGetCpuVendor(VOID)
PKPRCB Prcb = KeGetCurrentPrcb();
CPU_INFO CpuInfo;
- /* Assume no Vendor ID and fail if no CPUID Support. */
- Prcb->VendorString[0] = 0;
- if (!Prcb->CpuID) return 0;
-
/* Get the Vendor ID */
KiCpuId(&CpuInfo, 0);
@@ -465,7 +425,6 @@ NTAPI
KiGetCacheInformation(VOID)
{
PKIPCR Pcr = (PKIPCR)KeGetPcr();
- ULONG Vendor;
CPU_INFO CpuInfo;
ULONG CacheRequests = 0, i;
ULONG CurrentRegister;
@@ -476,12 +435,8 @@ KiGetCacheInformation(VOID)
/* Set default L2 size */
Pcr->SecondLevelCacheSize = 0;
- /* Get the Vendor ID and make sure we support CPUID */
- Vendor = KiGetCpuVendor();
- if (!Vendor) return;
-
/* Check the Vendor ID */
- switch (Vendor)
+ switch (KiGetCpuVendor())
{
/* Handle Intel case */
case CPU_INTEL:
@@ -1158,47 +1113,6 @@ KiSaveProcessorState(IN PKTRAP_FRAME TrapFrame,
KiSaveProcessorControlState(&Prcb->ProcessorState);
}
-CODE_SEG("INIT")
-BOOLEAN
-NTAPI
-KiIsNpxPresent(VOID)
-{
- ULONG Cr0;
- USHORT Magic;
-
- /* Set magic */
- Magic = 0xFFFF;
-
- /* Read CR0 and mask out FPU flags */
- Cr0 = __readcr0() & ~(CR0_MP | CR0_TS | CR0_EM | CR0_ET);
-
- /* Store on FPU stack */
-#ifdef _MSC_VER
- __asm fninit;
- __asm fnstsw Magic;
-#else
- asm volatile ("fninit;" "fnstsw %0" : "+m"(Magic));
-#endif
-
- /* Magic should now be cleared */
- if (Magic & 0xFF)
- {
- /* You don't have an FPU -- enable emulation for now */
- __writecr0(Cr0 | CR0_EM | CR0_TS);
- return FALSE;
- }
-
- /* You have an FPU, enable it */
- Cr0 |= CR0_ET;
-
- /* Enable INT 16 on 486 and higher */
- if (KeGetCurrentPrcb()->CpuType >= 3) Cr0 |= CR0_NE;
-
- /* Set FPU state */
- __writecr0(Cr0 | CR0_EM | CR0_TS);
- return TRUE;
-}
-
CODE_SEG("INIT")
BOOLEAN
NTAPI
@@ -1208,8 +1122,8 @@ KiIsNpxErrataPresent(VOID)
INT ErrataPresent;
ULONG Cr0;
- /* Disable interrupts */
- _disable();
+ /* Interrupts have to be disabled here. */
+ ASSERT(!(__readeflags() & EFLAGS_INTERRUPT_MASK));
/* Read CR0 and remove FPU flags */
Cr0 = __readcr0();
@@ -1247,9 +1161,6 @@ KiIsNpxErrataPresent(VOID)
/* Restore CR0 */
__writecr0(Cr0);
- /* Enable interrupts */
- _enable();
-
/* Return if there's an errata */
return ErrataPresent != 0;
}
@@ -1370,9 +1281,6 @@ KeSaveFloatingPointState(OUT PKFLOATING_SAVE Save)
ASSERT(KeGetCurrentIrql() <= DISPATCH_LEVEL);
UNIMPLEMENTED_ONCE;
- /* check if we are doing software emulation */
- if (!KeI386NpxPresent) return STATUS_ILLEGAL_FLOAT_CONTEXT;
-
FpState = ExAllocatePool(NonPagedPool, sizeof (FNSAVE_FORMAT));
if (!FpState) return STATUS_INSUFFICIENT_RESOURCES;
diff --git a/ntoskrnl/ke/i386/exp.c b/ntoskrnl/ke/i386/exp.c
index a64faa1d60c..7ed82f72017 100644
--- a/ntoskrnl/ke/i386/exp.c
+++ b/ntoskrnl/ke/i386/exp.c
@@ -434,30 +434,25 @@ KeContextToTrapFrame(IN PCONTEXT Context,
/* Get the FX Area */
FxSaveArea = (PFX_SAVE_AREA)(TrapFrame + 1);
- /* Check if NPX is present */
- if (KeI386NpxPresent)
- {
- /* Flush the NPX State */
- KiFlushNPXState(NULL);
+ /* Flush the NPX State */
+ KiFlushNPXState(NULL);
- /* Copy the FX State */
- RtlCopyMemory(&FxSaveArea->U.FxArea,
- &Context->ExtendedRegisters[0],
- MAXIMUM_SUPPORTED_EXTENSION);
+ /* Copy the FX State */
+ RtlCopyMemory(&FxSaveArea->U.FxArea,
+ &Context->ExtendedRegisters[0],
+ MAXIMUM_SUPPORTED_EXTENSION);
- /* Remove reserved bits from MXCSR */
- FxSaveArea->U.FxArea.MXCsr &= KiMXCsrMask;
+ /* Remove reserved bits from MXCSR */
+ FxSaveArea->U.FxArea.MXCsr &= KiMXCsrMask;
- /* Mask out any invalid flags */
- FxSaveArea->Cr0NpxState &= ~(CR0_EM | CR0_MP | CR0_TS);
+ /* Mask out any invalid flags */
+ FxSaveArea->Cr0NpxState &= ~(CR0_EM | CR0_MP | CR0_TS);
- /* Check if this is a VDM app */
- if (PsGetCurrentProcess()->VdmObjects)
- {
- /* Allow the EM flag */
- FxSaveArea->Cr0NpxState |= Context->FloatSave.Cr0NpxState &
- (CR0_EM | CR0_MP);
- }
+ /* Check if this is a VDM app */
+ if (PsGetCurrentProcess()->VdmObjects)
+ {
+ /* Allow the EM flag */
+ FxSaveArea->Cr0NpxState |= Context->FloatSave.Cr0NpxState & (CR0_EM
| CR0_MP);
}
}
@@ -468,88 +463,63 @@ KeContextToTrapFrame(IN PCONTEXT Context,
/* Get the FX Area */
FxSaveArea = (PFX_SAVE_AREA)(TrapFrame + 1);
- /* Check if NPX is present */
- if (KeI386NpxPresent)
- {
- /* Flush the NPX State */
- KiFlushNPXState(NULL);
+ /* Flush the NPX State */
+ KiFlushNPXState(NULL);
- /* Check if we have Fxsr support */
- if (KeI386FxsrPresent)
- {
- /* Convert the Fn Floating Point state to Fx */
- FxSaveArea->U.FxArea.ControlWord =
- (USHORT)Context->FloatSave.ControlWord;
- FxSaveArea->U.FxArea.StatusWord =
- (USHORT)Context->FloatSave.StatusWord;
- FxSaveArea->U.FxArea.TagWord =
- KiTagWordFnsaveToFxsave((USHORT)Context->FloatSave.TagWord);
- FxSaveArea->U.FxArea.ErrorOpcode =
- (USHORT)((Context->FloatSave.ErrorSelector >> 16) &
0xFFFF);
- FxSaveArea->U.FxArea.ErrorOffset =
- Context->FloatSave.ErrorOffset;
- FxSaveArea->U.FxArea.ErrorSelector =
- Context->FloatSave.ErrorSelector & 0xFFFF;
- FxSaveArea->U.FxArea.DataOffset =
- Context->FloatSave.DataOffset;
- FxSaveArea->U.FxArea.DataSelector =
- Context->FloatSave.DataSelector;
-
- /* Clear out the Register Area */
- RtlZeroMemory(&FxSaveArea->U.FxArea.RegisterArea[0],
- SIZE_OF_FX_REGISTERS);
-
- /* Loop the 8 floating point registers */
- for (i = 0; i < 8; i++)
- {
- /* Copy from Fn to Fx */
- RtlCopyMemory(FxSaveArea->U.FxArea.RegisterArea + (i * 16),
- Context->FloatSave.RegisterArea + (i * 10),
- 10);
- }
- }
- else
+ /* Check if we have Fxsr support */
+ if (KeI386FxsrPresent)
+ {
+ /* Convert the Fn Floating Point state to Fx */
+ FxSaveArea->U.FxArea.ControlWord =
(USHORT)Context->FloatSave.ControlWord;
+ FxSaveArea->U.FxArea.StatusWord =
(USHORT)Context->FloatSave.StatusWord;
+ FxSaveArea->U.FxArea.TagWord =
+ KiTagWordFnsaveToFxsave((USHORT)Context->FloatSave.TagWord);
+ FxSaveArea->U.FxArea.ErrorOpcode =
+ (USHORT)((Context->FloatSave.ErrorSelector >> 16) &
0xFFFF);
+ FxSaveArea->U.FxArea.ErrorOffset = Context->FloatSave.ErrorOffset;
+ FxSaveArea->U.FxArea.ErrorSelector = Context->FloatSave.ErrorSelector
& 0xFFFF;
+ FxSaveArea->U.FxArea.DataOffset = Context->FloatSave.DataOffset;
+ FxSaveArea->U.FxArea.DataSelector = Context->FloatSave.DataSelector;
+
+ /* Clear out the Register Area */
+ RtlZeroMemory(&FxSaveArea->U.FxArea.RegisterArea[0],
SIZE_OF_FX_REGISTERS);
+
+ /* Loop the 8 floating point registers */
+ for (i = 0; i < 8; i++)
{
- /* Copy the structure */
- FxSaveArea->U.FnArea.ControlWord = Context->FloatSave.
- ControlWord;
- FxSaveArea->U.FnArea.StatusWord = Context->FloatSave.
- StatusWord;
- FxSaveArea->U.FnArea.TagWord = Context->FloatSave.TagWord;
- FxSaveArea->U.FnArea.ErrorOffset = Context->FloatSave.
- ErrorOffset;
- FxSaveArea->U.FnArea.ErrorSelector = Context->FloatSave.
- ErrorSelector;
- FxSaveArea->U.FnArea.DataOffset = Context->FloatSave.
- DataOffset;
- FxSaveArea->U.FnArea.DataSelector = Context->FloatSave.
- DataSelector;
-
- /* Loop registers */
- for (i = 0; i < SIZE_OF_80387_REGISTERS; i++)
- {
- /* Copy registers */
- FxSaveArea->U.FnArea.RegisterArea[i] =
- Context->FloatSave.RegisterArea[i];
- }
+ /* Copy from Fn to Fx */
+ RtlCopyMemory(FxSaveArea->U.FxArea.RegisterArea + (i * 16),
+ Context->FloatSave.RegisterArea + (i * 10),
+ 10);
}
+ }
+ else
+ {
+ /* Copy the structure */
+ FxSaveArea->U.FnArea.ControlWord = Context->FloatSave.ControlWord;
+ FxSaveArea->U.FnArea.StatusWord = Context->FloatSave.StatusWord;
+ FxSaveArea->U.FnArea.TagWord = Context->FloatSave.TagWord;
+ FxSaveArea->U.FnArea.ErrorOffset = Context->FloatSave.ErrorOffset;
+ FxSaveArea->U.FnArea.ErrorSelector = Context->FloatSave.ErrorSelector;
+ FxSaveArea->U.FnArea.DataOffset = Context->FloatSave.DataOffset;
+ FxSaveArea->U.FnArea.DataSelector = Context->FloatSave.DataSelector;
- /* Mask out any invalid flags */
- FxSaveArea->Cr0NpxState &= ~(CR0_EM | CR0_MP | CR0_TS);
-
- /* Check if this is a VDM app */
- if (PsGetCurrentProcess()->VdmObjects)
+ /* Loop registers */
+ for (i = 0; i < SIZE_OF_80387_REGISTERS; i++)
{
- /* Allow the EM flag */
- FxSaveArea->Cr0NpxState |= Context->FloatSave.Cr0NpxState &
- (CR0_EM | CR0_MP);
+ /* Copy registers */
+ FxSaveArea->U.FnArea.RegisterArea[i] =
Context->FloatSave.RegisterArea[i];
}
}
- else
+
+ /* Mask out any invalid flags */
+ FxSaveArea->Cr0NpxState &= ~(CR0_EM | CR0_MP | CR0_TS);
+
+ /* Check if this is a VDM app */
+ if (PsGetCurrentProcess()->VdmObjects)
{
- /* FIXME: Handle FPU Emulation */
- //ASSERT(FALSE);
- UNIMPLEMENTED;
+ /* Allow the EM flag */
+ FxSaveArea->Cr0NpxState |= Context->FloatSave.Cr0NpxState & (CR0_EM
| CR0_MP);
}
}
@@ -698,17 +668,13 @@ KeTrapFrameToContext(IN PKTRAP_FRAME TrapFrame,
/* Get the FX Save Area */
FxSaveArea = (PFX_SAVE_AREA)(TrapFrame + 1);
- /* Make sure NPX is present */
- if (KeI386NpxPresent)
- {
- /* Flush the NPX State */
- KiFlushNPXState(NULL);
+ /* Flush the NPX State */
+ KiFlushNPXState(NULL);
- /* Copy the registers */
- RtlCopyMemory(&Context->ExtendedRegisters[0],
- &FxSaveArea->U.FxArea,
- MAXIMUM_SUPPORTED_EXTENSION);
- }
+ /* Copy the registers */
+ RtlCopyMemory(&Context->ExtendedRegisters[0],
+ &FxSaveArea->U.FxArea,
+ MAXIMUM_SUPPORTED_EXTENSION);
}
/* Handle Floating Point */
@@ -718,49 +684,38 @@ KeTrapFrameToContext(IN PKTRAP_FRAME TrapFrame,
/* Get the FX Save Area */
FxSaveArea = (PFX_SAVE_AREA)(TrapFrame + 1);
- /* Make sure we have an NPX */
- if (KeI386NpxPresent)
- {
- /* Check if we have Fxsr support */
- if (KeI386FxsrPresent)
- {
- /* Align the floating area to 16-bytes */
- FloatSaveArea = (FLOATING_SAVE_AREA*)
- ((ULONG_PTR)&FloatSaveBuffer.UnalignedArea &~
0xF);
-
- /* Get the State */
- KiFlushNPXState(FloatSaveArea);
- }
- else
- {
- /* We don't, use the FN area and flush the NPX State */
- FloatSaveArea = (FLOATING_SAVE_AREA*)&FxSaveArea->U.FnArea;
- KiFlushNPXState(NULL);
- }
+ /* Check if we have Fxsr support */
+ if (KeI386FxsrPresent)
+ {
+ /* Align the floating area to 16-bytes */
+ FloatSaveArea =
(FLOATING_SAVE_AREA*)((ULONG_PTR)&FloatSaveBuffer.UnalignedArea &~ 0xF);
- /* Copy structure */
- Context->FloatSave.ControlWord = FloatSaveArea->ControlWord;
- Context->FloatSave.StatusWord = FloatSaveArea->StatusWord;
- Context->FloatSave.TagWord = FloatSaveArea->TagWord;
- Context->FloatSave.ErrorOffset = FloatSaveArea->ErrorOffset;
- Context->FloatSave.ErrorSelector = FloatSaveArea->ErrorSelector;
- Context->FloatSave.DataOffset = FloatSaveArea->DataOffset;
- Context->FloatSave.DataSelector = FloatSaveArea->DataSelector;
- Context->FloatSave.Cr0NpxState = FxSaveArea->Cr0NpxState;
+ /* Get the State */
+ KiFlushNPXState(FloatSaveArea);
+ }
+ else
+ {
+ /* We don't, use the FN area and flush the NPX State */
+ FloatSaveArea = (FLOATING_SAVE_AREA*)&FxSaveArea->U.FnArea;
+ KiFlushNPXState(NULL);
+ }
- /* Loop registers */
- for (i = 0; i < SIZE_OF_80387_REGISTERS; i++)
- {
- /* Copy them */
- Context->FloatSave.RegisterArea[i] =
- FloatSaveArea->RegisterArea[i];
- }
- }
- else
- {
- /* FIXME: Handle Emulation */
- ASSERT(FALSE);
- }
+ /* Copy structure */
+ Context->FloatSave.ControlWord = FloatSaveArea->ControlWord;
+ Context->FloatSave.StatusWord = FloatSaveArea->StatusWord;
+ Context->FloatSave.TagWord = FloatSaveArea->TagWord;
+ Context->FloatSave.ErrorOffset = FloatSaveArea->ErrorOffset;
+ Context->FloatSave.ErrorSelector = FloatSaveArea->ErrorSelector;
+ Context->FloatSave.DataOffset = FloatSaveArea->DataOffset;
+ Context->FloatSave.DataSelector = FloatSaveArea->DataSelector;
+ Context->FloatSave.Cr0NpxState = FxSaveArea->Cr0NpxState;
+
+ /* Loop registers */
+ for (i = 0; i < SIZE_OF_80387_REGISTERS; i++)
+ {
+ /* Copy them */
+ Context->FloatSave.RegisterArea[i] = FloatSaveArea->RegisterArea[i];
+ }
}
/* Handle debug registers */
diff --git a/ntoskrnl/ke/i386/kiinit.c b/ntoskrnl/ke/i386/kiinit.c
index 10889c0195c..7f0651e260a 100644
--- a/ntoskrnl/ke/i386/kiinit.c
+++ b/ntoskrnl/ke/i386/kiinit.c
@@ -85,58 +85,6 @@ KiInitMachineDependent(VOID)
/* Check for PAT support and enable it */
if (KeFeatureBits & KF_PAT) KiInitializePAT();
- /* Assume no errata for now */
- SharedUserData->ProcessorFeatures[PF_FLOATING_POINT_PRECISION_ERRATA] = 0;
-
- /* Check if we have an NPX */
- if (KeI386NpxPresent)
- {
- /* Loop every CPU */
- i = KeActiveProcessors;
- for (Affinity = 1; i; Affinity <<= 1)
- {
- /* Check if this is part of the set */
- if (i & Affinity)
- {
- /* Run on this CPU */
- i &= ~Affinity;
- KeSetSystemAffinityThread(Affinity);
-
- /* Detect FPU errata */
- if (KiIsNpxErrataPresent())
- {
- /* Disable NPX support */
- KeI386NpxPresent = FALSE;
- SharedUserData->
- ProcessorFeatures[PF_FLOATING_POINT_PRECISION_ERRATA] =
- TRUE;
- break;
- }
- }
- }
- }
-
- /* If there's no NPX, then we're emulating the FPU */
- SharedUserData->ProcessorFeatures[PF_FLOATING_POINT_EMULATED] =
- !KeI386NpxPresent;
-
- /* Check if there's no NPX, so that we can disable associated features */
- if (!KeI386NpxPresent)
- {
- /* Remove NPX-related bits */
- KeFeatureBits &= ~(KF_XMMI64 | KF_XMMI | KF_FXSR | KF_MMX);
-
- /* Disable kernel flags */
- KeI386FxsrPresent = KeI386XMMIPresent = FALSE;
-
- /* Disable processor features that might've been set until now */
- SharedUserData->ProcessorFeatures[PF_FLOATING_POINT_PRECISION_ERRATA] =
- SharedUserData->ProcessorFeatures[PF_XMMI64_INSTRUCTIONS_AVAILABLE] =
- SharedUserData->ProcessorFeatures[PF_XMMI_INSTRUCTIONS_AVAILABLE] =
- SharedUserData->ProcessorFeatures[PF_3DNOW_INSTRUCTIONS_AVAILABLE] =
- SharedUserData->ProcessorFeatures[PF_MMX_INSTRUCTIONS_AVAILABLE] = 0;
- }
-
/* Check for CR4 support */
if (KeFeatureBits & KF_CR4)
{
@@ -459,6 +407,21 @@ KiVerifyCpuFeatures(PKPRCB Prcb)
KeBugCheckEx(UNSUPPORTED_PROCESSOR, 0x2, 0x00000001, 0, 0);
}
+ // Set up FPU-related CR0 flags.
+ ULONG Cr0 = __readcr0();
+ // Disable emulation and monitoring.
+ Cr0 &= ~(CR0_EM | CR0_MP);
+ // Enable FPU exceptions.
+ Cr0 |= CR0_NE;
+
+ __writecr0(Cr0);
+
+ // Check for Pentium FPU bug.
+ if (KiIsNpxErrataPresent())
+ {
+ KeBugCheckEx(UNSUPPORTED_PROCESSOR, 0x2, 0x00000001, 0, 0);
+ }
+
// 5. Save feature bits.
Prcb->FeatureBits = FeatureBits;
}
@@ -590,6 +553,7 @@ KiInitializeKernel(IN PKPROCESS InitProcess,
((PETHREAD)InitThread)->ThreadsProcess = (PEPROCESS)InitProcess;
/* Set basic CPU Features that user mode can read */
+ SharedUserData->ProcessorFeatures[PF_FLOATING_POINT_PRECISION_ERRATA] = FALSE;
SharedUserData->ProcessorFeatures[PF_MMX_INSTRUCTIONS_AVAILABLE] =
(KeFeatureBits & KF_MMX) ? TRUE: FALSE;
SharedUserData->ProcessorFeatures[PF_COMPARE_EXCHANGE_DOUBLE] =
diff --git a/ntoskrnl/ke/i386/thrdini.c b/ntoskrnl/ke/i386/thrdini.c
index 11bf02de2fb..ae9a599a8e2 100644
--- a/ntoskrnl/ke/i386/thrdini.c
+++ b/ntoskrnl/ke/i386/thrdini.c
@@ -152,28 +152,17 @@ KiInitializeContextThread(IN PKTHREAD Thread,
Context->FloatSave.DataSelector = 0;
}
- /* Check if the CPU has NPX */
- if (KeI386NpxPresent)
- {
- /* Set an intial NPX State */
- Context->FloatSave.Cr0NpxState = 0;
- FxSaveArea->Cr0NpxState = 0;
- FxSaveArea->NpxSavedCpu = 0;
-
- /* Now set the context flags depending on XMM support */
- ContextFlags |= (KeI386FxsrPresent) ? CONTEXT_EXTENDED_REGISTERS :
- CONTEXT_FLOATING_POINT;
-
- /* Set the Thread's NPX State */
- Thread->NpxState = NPX_STATE_NOT_LOADED;
- Thread->Header.NpxIrql = PASSIVE_LEVEL;
- }
- else
- {
- /* We'll use emulation */
- FxSaveArea->Cr0NpxState = CR0_EM;
- Thread->NpxState = NPX_STATE_NOT_LOADED &~ CR0_MP;
- }
+ /* Set an intial NPX State */
+ Context->FloatSave.Cr0NpxState = 0;
+ FxSaveArea->Cr0NpxState = 0;
+ FxSaveArea->NpxSavedCpu = 0;
+
+ /* Now set the context flags depending on XMM support */
+ ContextFlags |= (KeI386FxsrPresent) ? CONTEXT_EXTENDED_REGISTERS :
CONTEXT_FLOATING_POINT;
+
+ /* Set the Thread's NPX State */
+ Thread->NpxState = NPX_STATE_NOT_LOADED;
+ Thread->Header.NpxIrql = PASSIVE_LEVEL;
/* Disable any debug registers */
Context->ContextFlags &= ~CONTEXT_DEBUG_REGISTERS;
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Victor Perevertkin