[PATCH] x86/PCI: Ignore CPU non-addressable _CRS reserved memory resources

[PATCH] x86/PCI: Ignore CPU non-addressable _CRS reserved memory resources

[Gary Hade]

From: Gary Hade <garyhade@us.ibm.com>

This assures that a _CRS reserved host bridge window or 
window region is not used if it is not addressable by
the CPU.  The new code either trims the window to exclude
the non-addressable portion or totally ignores the window
if the entire window is non-addressable.

The current code has been shown to be problematic with
32-bit non-PAE kernels on systems where _CRS reserves
resources above 4GB.

Signed-off-by: Gary Hade <garyhade@us.ibm.com>
Reviewed-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Thomas Renninger <trenn@novell.com>
Cc: linux-kernel@vger.kernel.org
Cc: stable@kernel.org
---

 arch/x86/pci/acpi.c |   18 ++++++++++++++++--
 1 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/arch/x86/pci/acpi.c b/arch/x86/pci/acpi.c
index 404f21a..3557af7 100644
--- a/arch/x86/pci/acpi.c
+++ b/arch/x86/pci/acpi.c
@@ -149,7 +149,7 @@ setup_resource(struct acpi_resource *acpi_res, void *data)
 	struct acpi_resource_address64 addr;
 	acpi_status status;
 	unsigned long flags;
-	u64 start, end;
+	u64 start, orig_end, end;
 
 	status = resource_to_addr(acpi_res, &addr);
 	if (!ACPI_SUCCESS(status))
@@ -165,7 +165,21 @@ setup_resource(struct acpi_resource *acpi_res, void *data)
 		return AE_OK;
 
 	start = addr.minimum + addr.translation_offset;
-	end = addr.maximum + addr.translation_offset;
+	orig_end = end = addr.maximum + addr.translation_offset;
+
+	/* Exclude non-addressable range or non-addressable portion of range */
+	end = min(end, (u64)iomem_resource.end);
+	if (end <= start) {
+		dev_info(&info->bridge->dev,
+			"host bridge window [%#llx-%#llx] "
+			"(ignored, not CPU addressable)\n", start, orig_end);
+		return AE_OK;
+	} else if (orig_end != end) {
+		dev_info(&info->bridge->dev,
+			"host bridge window [%#llx-%#llx] "
+			"([%#llx-%#llx] ignored, not CPU addressable)\n", 
+			start, orig_end, end + 1, orig_end);
+	}
 
 	res = &info->res[info->res_num];
 	res->name = info->name;

Re: [PATCH] x86/PCI: Ignore CPU non-addressable _CRS reserved memory resources

[Jesse Barnes]

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On Mon, 14 Nov 2011 15:42:16 -0800
Gary Hade <garyhade@us.ibm.com> wrote:

> 
> From: Gary Hade <garyhade@us.ibm.com>
> 
> This assures that a _CRS reserved host bridge window or 
> window region is not used if it is not addressable by
> the CPU.  The new code either trims the window to exclude
> the non-addressable portion or totally ignores the window
> if the entire window is non-addressable.
> 
> The current code has been shown to be problematic with
> 32-bit non-PAE kernels on systems where _CRS reserves
> resources above 4GB.
> 
> Signed-off-by: Gary Hade <garyhade@us.ibm.com>
> Reviewed-by: Bjorn Helgaas <bhelgaas@google.com>
> Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
> Cc: Bjorn Helgaas <bhelgaas@google.com>
> Cc: Thomas Renninger <trenn@novell.com>
> Cc: linux-kernel@vger.kernel.org
> Cc: stable@kernel.org
> ---

Applied to linux-next (don't want to send something this fundamental to
Linus at this late stage).  It can land in stable if it turns out ok in
-rc1.

Thanks,
-- 
Jesse Barnes, Intel Open Source Technology Center

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