[PATCH2] Pentium Pro - sysenter - doublefault

[Jim Houston <jim.houston@comcast.net>]

On Thu, 2003-08-21 at 17:32, Mikael Pettersson wrote:
>  > The logic above is exactly what Intel says to do in "IA-32 Intel®
>  > Architecture Software Developer's Manual, Volume 2: Instruction Set
>  > Reference" on page 3-767.  It also says that sysenter was added to the
>  > Pentium II.
> 
> I double-checked AP-485 (24161823.pdf, the "real" reference to CPUID),
> and it says (section 3.4) that SEP is unsupported when the signature
> as a whole is less that 0x633. This means all PPros, and PII Model 3s
> with steppings less than 3.
> 

Hi Dave, Everyone,

This make sense. Here is Mikael's suggested code as a patch.

Dave, I picked your name from the maintainers list.  Please 
feed this patch up the chain.


Jim Houston - Concurrent Computer Corp. 


diff -urN linux-2.6.0-test3.orig/arch/i386/kernel/cpu/intel.c
linux-2.6.0-test3.new/arch/i386/kernel/cpu/intel.c
--- linux-2.6.0-test3.orig/arch/i386/kernel/cpu/intel.c	2003-08-20
10:30:14.000000000 -0400
+++ linux-2.6.0-test3.new/arch/i386/kernel/cpu/intel.c	2003-08-21
21:34:40.000000000 -0400
@@ -246,7 +246,8 @@
 	}
 
 	/* SEP CPUID bug: Pentium Pro reports SEP but doesn't have it */
-	if ( c->x86 == 6 && c->x86_model < 3 && c->x86_mask < 3 )
+	if ( c->x86 == 6 && ((c->x86_model < 3) ||
+				(c->x86_model == 3 && c->x86_mask < 3)))
 		clear_bit(X86_FEATURE_SEP, c->x86_capability);
 	
 	/* Names for the Pentium II/Celeron processors