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[FAST486]

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- Always use the descriptor type, and never the limit, to identify
legacy vs. modern TSSes.
- Don't forget to write back the modified TSS link.


svn path=/trunk/; revision=69407
This commit is contained in:
Aleksandar Andrejevic 2015-09-28 18:51:48 +00:00
parent 304222462c
commit 646f9543f1
1 changed files with 55 additions and 9 deletions
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64
reactos/lib/fast486/common.c
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@ -716,7 +716,8 @@ Fast486TaskSwitch(PFAST486_STATE State, FAST486_TASK_SWITCH_TYPE Type, USHORT Se
if (!Fast486ReadLinearMemory(State,
NewTssAddress,
&NewTss,
NewTssLimit >= (sizeof(FAST486_TSS) - 1)
(NewTssDescriptor.Signature == FAST486_TSS_SIGNATURE)
|| (NewTssDescriptor.Signature == FAST486_BUSY_TSS_SIGNATURE)
? sizeof(FAST486_TSS) : sizeof(FAST486_LEGACY_TSS),
FALSE))
{
@ -756,8 +757,37 @@ Fast486TaskSwitch(PFAST486_STATE State, FAST486_TASK_SWITCH_TYPE Type, USHORT Se
else
{
/* Store the link */
if (NewTssLimit >= (sizeof(FAST486_TSS) - 1)) NewTss.Link = State->TaskReg.Selector;
else NewLegacyTss->Link = State->TaskReg.Selector;
if ((NewTssDescriptor.Signature == FAST486_TSS_SIGNATURE)
|| (NewTssDescriptor.Signature == FAST486_BUSY_TSS_SIGNATURE))
{
NewTss.Link = State->TaskReg.Selector;
/* Write back the new TSS link */
if (!Fast486WriteLinearMemory(State,
NewTssAddress,
&NewTss.Link,
sizeof(NewTss.Link),
FALSE))
{
/* Exception occurred */
return FALSE;
}
}
else
{
NewLegacyTss->Link = State->TaskReg.Selector;
/* Write back the new legacy TSS link */
if (!Fast486WriteLinearMemory(State,
NewTssAddress,
&NewLegacyTss->Link,
sizeof(NewLegacyTss->Link),
FALSE))
{
/* Exception occurred */
return FALSE;
}
}
}
/* Save the current task into the TSS */
@ -814,7 +844,17 @@ Fast486TaskSwitch(PFAST486_STATE State, FAST486_TASK_SWITCH_TYPE Type, USHORT Se
}
/* Mark the new task as busy */
NewTssDescriptor.Signature = FAST486_BUSY_TSS_SIGNATURE;
if (NewTssDescriptor.Signature == FAST486_TSS_SIGNATURE
|| NewTssDescriptor.Signature == FAST486_BUSY_TSS_SIGNATURE)
{
/* 32-bit TSS */
NewTssDescriptor.Signature = FAST486_BUSY_TSS_SIGNATURE;
}
else
{
/* 16-bit TSS */
NewTssDescriptor.Signature = FAST486_BUSY_TSS_16_SIGNATURE;
}
/* Write back the new TSS descriptor */
if (!Fast486WriteLinearMemory(State,
@ -835,7 +875,7 @@ Fast486TaskSwitch(PFAST486_STATE State, FAST486_TASK_SWITCH_TYPE Type, USHORT Se
State->TaskReg.Base = NewTssAddress;
State->TaskReg.Limit = NewTssLimit;
if (NewTssLimit >= (sizeof(FAST486_TSS) - 1))
if (NewTssDescriptor.Signature == FAST486_BUSY_TSS_SIGNATURE)
{
/* Change the page directory */
State->ControlRegisters[FAST486_REG_CR3] = NewTss.Cr3;
@ -845,8 +885,14 @@ Fast486TaskSwitch(PFAST486_STATE State, FAST486_TASK_SWITCH_TYPE Type, USHORT Se
Fast486FlushTlb(State);
/* Update the CPL */
if (NewTssLimit >= (sizeof(FAST486_TSS) - 1)) State->Cpl = GET_SEGMENT_RPL(NewTss.Cs);
else State->Cpl = GET_SEGMENT_RPL(NewLegacyTss->Cs);
if (NewTssDescriptor.Signature == FAST486_BUSY_TSS_SIGNATURE)
{
State->Cpl = GET_SEGMENT_RPL(NewTss.Cs);
}
else
{
State->Cpl = GET_SEGMENT_RPL(NewLegacyTss->Cs);
}
#ifndef FAST486_NO_PREFETCH
/* Context switching invalidates the prefetch */
@ -854,7 +900,7 @@ Fast486TaskSwitch(PFAST486_STATE State, FAST486_TASK_SWITCH_TYPE Type, USHORT Se
#endif
/* Load the registers */
if (NewTssLimit >= (sizeof(FAST486_TSS) - 1))
if (NewTssDescriptor.Signature == FAST486_BUSY_TSS_SIGNATURE)
{
State->InstPtr.Long = State->SavedInstPtr.Long = NewTss.Eip;
State->Flags.Long = NewTss.Eflags;
@ -970,7 +1016,7 @@ Fast486TaskSwitch(PFAST486_STATE State, FAST486_TASK_SWITCH_TYPE Type, USHORT Se
return FALSE;
}
if (NewTssLimit >= (sizeof(FAST486_TSS) - 1))
if (NewTssDescriptor.Signature == FAST486_BUSY_TSS_SIGNATURE)
{
if (!Fast486LoadSegmentInternal(State,
FAST486_REG_FS,