commit ca8642f606ce22de23bae08a5044067f98de855b
author Andi Kleen <ak@suse.de> Wed Jan 11 22:44:27 2006 +0100
committer Linus Torvalds <torvalds@g5.osdl.org> Wed Jan 11 19:04:54 2006 -0800
tree 143dd169cbba9d58629ca74d618cbfa41964c2f8
parent d25bf7e5fe73b5b6d2246ab0be08ae35d718456b

[PATCH] x86_64: Fix off by one in IOMMU check

Fix off by one when checking if the machine has enougn memory to need IOMMU
This caused the IOMMUs to be needlessly enabled for mem=4G

Based on a patch from Jon Mason

Signed-off-by: jdmason@us.ibm.com
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

arch/x86_64/kernel/aperture.c

diff --git a/arch/x86_64/kernel/aperture.c b/arch/x86_64/kernel/aperture.c
index c7f4fdd..e4e2b7d 100644
--- a/arch/x86_64/kernel/aperture.c
+++ b/arch/x86_64/kernel/aperture.c
@@ -23,6 +23,7 @@
 #include <asm/io.h>
 #include <asm/proto.h>
 #include <asm/pci-direct.h>
+#include <asm/dma.h>
 
 int iommu_aperture;
 int iommu_aperture_disabled __initdata = 0;
@@ -247,7 +248,7 @@
 		/* Got the aperture from the AGP bridge */
 	} else if (swiotlb && !valid_agp) {
 		/* Do nothing */
-	} else if ((!no_iommu && end_pfn >= 0xffffffff>>PAGE_SHIFT) ||
+	} else if ((!no_iommu && end_pfn >= MAX_DMA32_PFN) ||
 		   force_iommu ||
 		   valid_agp ||
 		   fallback_aper_force) { 

arch/x86_64/kernel/io_apic.c

diff --git a/arch/x86_64/kernel/io_apic.c b/arch/x86_64/kernel/io_apic.c
index bdc5899..83ea86e 100644
--- a/arch/x86_64/kernel/io_apic.c
+++ b/arch/x86_64/kernel/io_apic.c
@@ -37,6 +37,7 @@
 #include <asm/proto.h>
 #include <asm/mach_apic.h>
 #include <asm/acpi.h>
+#include <asm/dma.h>
 
 #define __apicdebuginit  __init
 
@@ -281,7 +282,7 @@
 				switch (vendor) { 
 				case PCI_VENDOR_ID_VIA:
 #ifdef CONFIG_GART_IOMMU
-					if ((end_pfn >= (0xffffffff>>PAGE_SHIFT) ||
+					if ((end_pfn > MAX_DMA32_PFN ||
 					     force_iommu) &&
 					    !iommu_aperture_allowed) {
 						printk(KERN_INFO

arch/x86_64/kernel/pci-gart.c

diff --git a/arch/x86_64/kernel/pci-gart.c b/arch/x86_64/kernel/pci-gart.c
index 2b865c9..116e00f 100644
--- a/arch/x86_64/kernel/pci-gart.c
+++ b/arch/x86_64/kernel/pci-gart.c
@@ -804,7 +804,7 @@
 	} 
 	
 	if (no_iommu ||
-	    (!force_iommu && end_pfn < 0xffffffff>>PAGE_SHIFT) ||
+	    (!force_iommu && (end_pfn-1) < 0xffffffff>>PAGE_SHIFT) ||
 	    !iommu_aperture ||
 	    (no_agp && init_k8_gatt(&info) < 0)) {
 		printk(KERN_INFO "PCI-DMA: Disabling IOMMU.\n"); 

arch/x86_64/mm/init.c

diff --git a/arch/x86_64/mm/init.c b/arch/x86_64/mm/init.c
index 1faae5f..5337ca0 100644
--- a/arch/x86_64/mm/init.c
+++ b/arch/x86_64/mm/init.c
@@ -424,7 +424,7 @@
 
 #ifdef CONFIG_SWIOTLB
 	if (!iommu_aperture &&
-	    (end_pfn >= 0xffffffff>>PAGE_SHIFT || force_iommu))
+	    ((end_pfn-1) >= 0xffffffff>>PAGE_SHIFT || force_iommu))
 	       swiotlb = 1;
 	if (swiotlb)
 		swiotlb_init();