On Tue, Jul 01, 2008 at 07:59:42PM +0000, Sean Young wrote:
quoted text
> On Mon, Jun 30, 2008 at 03:42:47PM -0700, H. Peter Anvin wrote:
> > diff --git a/arch/x86/boot/pmjump.S b/arch/x86/boot/pmjump.S
> > index ab049d4..141b6e2 100644
> > --- a/arch/x86/boot/pmjump.S
> > +++ b/arch/x86/boot/pmjump.S
> > @@ -33,6 +33,8 @@ protected_mode_jump:
> >  	movw	%cs, %bx
> >  	shll	, %ebx
> >  	addl	%ebx, 2f
> > +	jmp	1f			# Short jump to serialize on 386/486
> > +1:
> >  
> >  	movw	$__BOOT_DS, %cx
> >  	movw	$__BOOT_TSS, %di
> > @@ -40,8 +42,6 @@ protected_mode_jump:
> >  	movl	%cr0, %edx
> >  	orb	$X86_CR0_PE, %dl	# Protected mode
> >  	movl	%edx, %cr0
> > -	jmp	1f			# Short jump to serialize on 386/486
> > -1:
> >  
> >  	# Transition to 32-bit mode
> >  	.byte	0x66, 0xea		# ljmpl opcode
> 
> I'm afraid it doesn't work. Maybe I can find something in the AMD Elan
> documentation. Would a fence make sense?

I was just trying to confirm this with postive and negative tests which 
is failing. I'm probably being an idiot, please let systematically test
this.

This does not seem like the heisenbug category, or is it?


Sean
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