RE: [ros-cvs] CVS Update: reactos

[Hartmut Birr]

Hi,

this changes prevents from using debug print's in the very early boot phase,
because the processor runs at HIGH_LEVEL and asserts in KfAcquireSpinLock.

- Hartmut
> -----Original Message-----
> From: [e-mail] 
> [mailto:[e-mail]] On Behalf Of 
> [e-mail]
> Sent: Saturday, October 30, 2004 6:30 AM
> To: [e-mail]
> Subject: [ros-cvs] CVS Update: reactos
>
> CVSROOT:	/CVS/ReactOS
> Module name:	reactos
> Repository:	reactos/hal/halx86/
> Changes by:	[e-mail]	04/10/30 06:30:05
>
> Modified files:
>    reactos/hal/halx86/: display.c
>
> Log message:
> Use KfAcquireSpinLock/KfReleaseSpinLock instead of
>
> KiAcquireSpinLock/KiReleaseSpinLock.
>
> Ros-cvs mailing list
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> http://reactos.com/mailman/listinfo/ros-cvs

[Filip Navara]

Hartmut Birr wrote:
> Hi,
>
> this changes prevents from using debug print's in the very early boot phase,
> because the processor runs at HIGH_LEVEL and asserts in KfAcquireSpinLock.
> Hartmut

The problem is that KiAcquireSpinLock is essentially useless on UP and 
doesn't protect anything. Would you agree with the attached patch?

Regards,
Filip

Index: hal/halx86/display.c
===================================================================
RCS file: /CVS/ReactOS/reactos/hal/halx86/display.c,v
retrieving revision 1.16
diff -u -r1.16 display.c
--- hal/halx86/display.c	30 Oct 2004 13:30:03 -0000	1.16
+++ hal/halx86/display.c	31 Oct 2004 13:33:26 -0000
@@ -682,7 +682,14 @@

pch = String;

-  OldIrql = KfAcquireSpinLock(&Lock);
+  if (KeGetCurrentIrql() <= DISPATCH_LEVEL)
+    {
+      OldIrql = KfAcquireSpinLock(&Lock);
+    }
+  else 
+    {
+      OldIrql = HIGH_LEVEL;
+    }

Ki386SaveFlags(Flags);
   Ki386DisableInterrupts();
@@ -749,7 +756,11 @@
   WRITE_PORT_UCHAR((PUCHAR)VGA_CRTC_DATA, (UCHAR)((offset >> 8) & 0xff));
 #endif
   Ki386RestoreFlags(Flags);
-  KfReleaseSpinLock(&Lock, OldIrql);
+
+  if (OldIrql <= DISPATCH_LEVEL)
+    {
+      KfReleaseSpinLock(&Lock, OldIrql);
+    }
 }

VOID STDCALL

[Hartmut Birr]

> -----Original Message-----
> From: [e-mail] 
> [mailto:[e-mail]] On Behalf Of Filip Navara
> Sent: Sunday, October 31, 2004 2:36 PM
> To: ReactOS Development List
> Subject: Re: [ros-dev] RE: [ros-cvs] CVS Update: reactos
>
> The problem is that KiAcquireSpinLock is essentially useless 
> on UP and 
> doesn't protect anything.

You are right.
> Would you agree with the attached patch?

I don't agree, because DbgPrint/HalDisplayString can be called on each irql.
We must always raise the irql to HIGH_LEVEL.

- Hartmut

[Filip Navara]

Hartmut Birr wrote:
> > Would you agree with the attached patch?
>
> I don't agree, because DbgPrint/HalDisplayString can be called on each irql.
> We must always raise the irql to HIGH_LEVEL.

Oops, sorry. I always forget about MP.

- Filip