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NMI Support Patch 2:

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[HAL]: Simplify IDT write-protection handling (always make it R/W and restore it to previous state).
    [HAL]: Avoid two superflous TLB flushes.


svn path=/trunk/; revision=44842
This commit is contained in:
ReactOS Portable Systems Group 2009-12-31 23:56:40 +00:00
parent 2e1b82cf72
commit fd1ccbe10c
1 changed files with 5 additions and 21 deletions
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26
reactos/hal/halx86/generic/bios.c
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@ -254,18 +254,8 @@ HalpBiosDisplayReset(VOID)
* the cmpxchg8b lock errata. Unprotect them here so we can set our custom
* invalid op-code handler.
*/
if (KeGetCurrentPrcb()->CpuType == 5)
{
/* Get the PTE and check if it is has been write protected yet */
IdtPte = GetPteAddress(((PKIPCR)KeGetPcr())->IDT);
if (IdtPte->Write == 0)
{
/* Remove the protection and flush the TLB */
IdtPte->Write = 1;
__writecr3(__readcr3());
RestoreWriteProtection = TRUE;
}
}
IdtPte = GetPteAddress(((PKIPCR)KeGetPcr())->IDT);
RestoreWriteProtection = IdtPte->Write;
/* Use special invalid opcode and GPF trap handlers */
HalpSwitchToRealModeTrapHandlers();
@ -279,15 +269,9 @@ HalpBiosDisplayReset(VOID)
/* Restore kernel trap handlers */
HalpRestoreTrapHandlers();
/* Check if we removed the write protection before */
if (RestoreWriteProtection)
{
/* Get the PTE, restore the write protection and flush the TLB */
IdtPte = GetPteAddress(((PKIPCR)KeGetPcr())->IDT);
IdtPte->Write = 0;
__writecr3(__readcr3());
}
/* Restore write permission */
IdtPte->Write = RestoreWriteProtection;
/* Restore TSS and IOPM */
HalpRestoreIoPermissionsAndTask();