Re: [ros-dev] [ros-diffs] [dgorbachev] 42305: Add a hack in KiSystemStartupReal function until Better Times.

[Aleksey Bragin]

That function is not supposed to be called by old bootloader
directly. Why is that needed? And why in this function?
WBR,
Aleksey Bragin.
On Jul 30, 2009, at 9:54 PM, dgorbachev(a)svn.reactos.org wrote:
>   Author: dgorbachev
>  Date: Thu Jul 30 19:54:01 2009
>  New Revision: 42305
>  URL: http://svn.reactos.org/svn/reactos?rev=42305&view=rev
>  Log:
>  Add a hack in KiSystemStartupReal function until Better Times.
>  Modified:
>      trunk/reactos/ntoskrnl/ke/i386/kiinit.c
>  Modified: trunk/reactos/ntoskrnl/ke/i386/kiinit.c
>  URL: http://svn.reactos.org/svn/reactos/trunk/reactos/ntoskrnl/ke/
>  i386/kiinit.c?rev=42305&r1=42304&r2=42305&view=diff
>  ======================================================================
>  ========
>  --- trunk/reactos/ntoskrnl/ke/i386/kiinit.c [iso-8859-1] (original)
>  +++ trunk/reactos/ntoskrnl/ke/i386/kiinit.c [iso-8859-1] Thu Jul 30
>  19:54:01 2009
>  @@ -712,18 +712,34 @@
>       Ke386SetDs(KGDT_R3_DATA | RPL_MASK);
>       Ke386SetEs(KGDT_R3_DATA | RPL_MASK);
>  -    /* Save NMI and double fault traps */
>  -    RtlCopyMemory(&NmiEntry, &Idt[2], sizeof(KIDTENTRY));
>  -    RtlCopyMemory(&DoubleFaultEntry, &Idt[8], sizeof(KIDTENTRY));
>  -
>  -    /* Copy kernel's trap handlers */
>  -    RtlCopyMemory(Idt,
>  -                  (PVOID)KiIdtDescriptor.Base,
>  -                  KiIdtDescriptor.Limit + 1);
>  -
>  -    /* Restore NMI and double fault */
>  -    RtlCopyMemory(&Idt[2], &NmiEntry, sizeof(KIDTENTRY));
>  -    RtlCopyMemory(&Idt[8], &DoubleFaultEntry, sizeof(KIDTENTRY));
>  +    /* HACK compensates for KiRosPrepareForSystemStartup hack */
>  +    if ((ULONG)Idt == KiIdtDescriptor.Base)
>  +    {
>  +        USHORT FlippedSelector;
>  +
>  +        FlippedSelector = KiIdt[2].Selector;
>  +        KiIdt[2].Selector = KiIdt[2].ExtendedOffset;
>  +        KiIdt[2].ExtendedOffset = FlippedSelector;
>  +
>  +        FlippedSelector = KiIdt[8].Selector;
>  +        KiIdt[8].Selector = KiIdt[8].ExtendedOffset;
>  +        KiIdt[8].ExtendedOffset = FlippedSelector;
>  +    }
>  +    else
>  +    {
>  +        /* Save NMI and double fault traps */
>  +        RtlCopyMemory(&NmiEntry, &Idt[2], sizeof(KIDTENTRY));
>  +        RtlCopyMemory(&DoubleFaultEntry, &Idt[8], sizeof(KIDTENTRY));
>  +
>  +        /* Copy kernel's trap handlers */
>  +        RtlCopyMemory(Idt,
>  +                      (PVOID)KiIdtDescriptor.Base,
>  +                      KiIdtDescriptor.Limit + 1);
>  +
>  +        /* Restore NMI and double fault */
>  +        RtlCopyMemory(&Idt[2], &NmiEntry, sizeof(KIDTENTRY));
>  +        RtlCopyMemory(&Idt[8], &DoubleFaultEntry, sizeof(KIDTENTRY));
>  +    }
>   AppCpuInit:
>       /* Loop until we can release the freeze lock */
>