linux-kernel - Re: PCI resource problems caused by improper address rounding

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Date:	Sat, 22 Dec 2007 01:20:06 -0800
From:	Andrew Morton <akpm@...ux-foundation.org>
To:	Ivan Kokshaysky <ink@...assic.park.msu.ru>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Richard Henderson <rth@...ddle.net>,
	Chuck Ebbert <cebbert@...hat.com>,
	linux-kernel <linux-kernel@...r.kernel.org>,
	Daniel Ritz <daniel.ritz@....ch>, Greg KH <greg@...ah.com>
Subject: Re: PCI resource problems caused by improper address rounding

On Sat, 22 Dec 2007 01:12:18 -0800 Andrew Morton <akpm@...ux-foundation.org> wrote:

> On Thu, 20 Dec 2007 11:46:16 +0300 Ivan Kokshaysky <ink@...assic.park.msu.ru> wrote:
> 
> > PCI: do respect full 64-bit address for bridge prefetch window
> > 
> > Prevent the prefetch window from being programmed with a bogus address
> > when its respective resource gets allocated above the 4G mark.
> > 
> > Note that we cannot yet guarantee correct resource allocations
> > above 4G, though it might work in some simple cases.
> > 
> 
> So.. did we agree that this patch is good to go?

Oh, I see Greg merged a differnet patch.

> > --- a/drivers/pci/setup-bus.c
> > +++ b/drivers/pci/setup-bus.c
> > @@ -208,8 +208,11 @@ pci_setup_bridge(struct pci_bus *bus)
> >  	}
> >  	pci_write_config_dword(bridge, PCI_PREF_MEMORY_BASE, l);
> >  
> > -	/* Clear out the upper 32 bits of PREF base. */
> > -	pci_write_config_dword(bridge, PCI_PREF_BASE_UPPER32, 0);
> > +	/* Set up the upper 32 bits of PREF base/limit. */
> > +	l = region.start >> 16 >> 16;
> 
> We have the little upper_32_bits() helper for this.
> 

Which could use this.

--- a/drivers/pci/setup-bus.c~gregkh-pci-pci-fix-bus-resource-assignment-on-32-bits-with-64b-resources-cleanup
+++ a/drivers/pci/setup-bus.c
@@ -206,10 +206,8 @@ pci_setup_bridge(struct pci_bus *bus)
 	if (bus->resource[2]->flags & IORESOURCE_PREFETCH) {
 		l = (region.start >> 16) & 0xfff0;
 		l |= region.end & 0xfff00000;
-#ifdef CONFIG_RESOURCES_64BIT
-		bu = region.start >> 32;
-		lu = region.end >> 32;
-#endif
+		bu = upper_32_bits(region.start);
+		lu = upper_32_bits(region.end);
 		DBG(KERN_INFO "  PREFETCH window: 0x%016llx-0x%016llx\n",
 		    (unsigned long long)region.start,
 		    (unsigned long long)region.end);

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