Re: [ros-dev] [ros-diffs] [cgutman] 54418: [HALX86] - Do not allow software interrupts to preempt code running with interrupts disabled during KfLowerIrql

[Aleksey Bragin]

I would like to ask our kernel gurus if this one is correct.

WBR,
Aleksey Bragin.

On 18.11.2011 22:53, [e-mail] wrote:
> Author: cgutman
> Date: Fri Nov 18 18:53:41 2011
> New Revision: 54418
>
> URL: http://svn.reactos.org/svn/reactos?rev=54418&view=rev
> Log:
> [HALX86]
> Do not allow software interrupts to preempt code running with interrupts disabled during KfLowerIrql
>
> Modified:
>      trunk/reactos/hal/halx86/up/pic.c
>
> Modified: trunk/reactos/hal/halx86/up/pic.c
> URL: http://svn.reactos.org/svn/reactos/trunk/reactos/hal/halx86/up/pic.c?rev=544...
> ==============================================================================
> --- trunk/reactos/hal/halx86/up/pic.c [iso-8859-1] (original)
> +++ trunk/reactos/hal/halx86/up/pic.c [iso-8859-1] Fri Nov 18 18:53:41 2011
> @@ -665,26 +665,30 @@
>   /* Set old IRQL */
>   Pcr->Irql = OldIrql;
> /* Check for pending software interrupts and compare with current IRQL */
> PendingIrqlMask = Pcr->IRR&  FindHigherIrqlMask[OldIrql];
> if (PendingIrqlMask)
> {
>    /* Check if pending IRQL affects hardware state */
>    BitScanReverse(&PendingIrql, PendingIrqlMask);
>    if (PendingIrql>  DISPATCH_LEVEL)
> /* Make sure interrupts were enabled */
> if (EFlags&  EFLAGS_INTERRUPT_MASK)
> {
>    /* Check for pending software interrupts and compare with current IRQL */
>    PendingIrqlMask = Pcr->IRR&  FindHigherIrqlMask[OldIrql];
>    if (PendingIrqlMask)
>     {
>        /* Set new PIC mask */
>        Mask.Both = Pcr->IDR;
>        __outbyte(PIC1_DATA_PORT, Mask.Master);
>        __outbyte(PIC2_DATA_PORT, Mask.Slave);
>        /* Clear IRR bit */
>        Pcr->IRR ^= (1<<  PendingIrql);
>        /* Check if pending IRQL affects hardware state */
>        BitScanReverse(&PendingIrql, PendingIrqlMask);
>        if (PendingIrql>  DISPATCH_LEVEL)
>        {
>            /* Set new PIC mask */
>            Mask.Both = Pcr->IDR;
>            __outbyte(PIC1_DATA_PORT, Mask.Master);
>            __outbyte(PIC2_DATA_PORT, Mask.Slave);
>            /* Clear IRR bit */
>            Pcr->IRR ^= (1<<  PendingIrql);
>        }
>        /* Now handle pending interrupt */
>        SWInterruptHandlerTable[PendingIrql]();
>     }
>    /* Now handle pending interrupt */
>    SWInterruptHandlerTable[PendingIrql]();
> }
>
> /* Restore interrupt state */