[ 09/79] x86/PCI: Map PCI setup data with ioremap() so it can be in highmem

From: Greg Kroah-Hartman
Date: Tue Jun 11 2013 - 16:22:22 EST

3.9-stable review patch. If anyone has any objections, please let me know.


From: Matt Fleming <matt.fleming@xxxxxxxxx>

commit 65694c5aaddfedd9da082e4e150cafc6b3fc8a6a upstream.

f9a37be0f0 ("x86: Use PCI setup data") added support for using PCI ROM
images from setup_data. This used phys_to_virt(), which is not valid for
highmem addresses, and can cause a crash when booting a 32-bit kernel via
the EFI boot stub.

pcibios_add_device() assumes that the physical addresses stored in
setup_data are accessible via the direct kernel mapping, and that calling
phys_to_virt() is valid. This isn't guaranteed to be true on x86 where the
direct mapping range is much smaller than on x86-64.

Calling phys_to_virt() on a highmem address results in the following:

BUG: unable to handle kernel paging request at 39a3c198
IP: [<c262be0f>] pcibios_add_device+0x2f/0x90
Call Trace:
[<c2370c73>] pci_device_add+0xe3/0x130
[<c274640b>] pci_scan_single_device+0x8b/0xb0
[<c2370d08>] pci_scan_slot+0x48/0x100
[<c2371904>] pci_scan_child_bus+0x24/0xc0
[<c262a7b0>] pci_acpi_scan_root+0x2c0/0x490
[<c23b7203>] acpi_pci_root_add+0x312/0x42f

The solution is to use ioremap() instead of phys_to_virt() to map the
setup data into the kernel address space.

[bhelgaas: changelog]
Tested-by: Jani Nikula <jani.nikula@xxxxxxxxx>
Signed-off-by: Matt Fleming <matt.fleming@xxxxxxxxx>
Signed-off-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
Cc: Matthew Garrett <mjg59@xxxxxxxxxxxxx>
Cc: Seth Forshee <seth.forshee@xxxxxxxxxxxxx>
Cc: Jesse Barnes <jbarnes@xxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

arch/x86/pci/common.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

--- a/arch/x86/pci/common.c
+++ b/arch/x86/pci/common.c
@@ -617,7 +617,9 @@ int pcibios_add_device(struct pci_dev *d

pa_data = boot_params.hdr.setup_data;
while (pa_data) {
- data = phys_to_virt(pa_data);
+ data = ioremap(pa_data, sizeof(*rom));
+ if (!data)
+ return -ENOMEM;

if (data->type == SETUP_PCI) {
rom = (struct pci_setup_rom *)data;
@@ -634,6 +636,7 @@ int pcibios_add_device(struct pci_dev *d
pa_data = data->next;
+ iounmap(data);
return 0;

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/