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[PATCH 4.5 026/238] PCI: Disable IO/MEM decoding for devices with non-compliant BARs

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

------------------

From: Bjorn Helgaas <bhelgaas@google.com>

commit b84106b4e2290c081cdab521fa832596cdfea246 upstream.

The PCI config header (first 64 bytes of each device's config space) is
defined by the PCI spec so generic software can identify the device and
manage its usage of I/O, memory, and IRQ resources.

Some non-spec-compliant devices put registers other than BARs where the
BARs should be.  When the PCI core sizes these "BARs", the reads and writes
it does may have unwanted side effects, and the "BAR" may appear to
describe non-sensical address space.

Add a flag bit to mark non-compliant devices so we don't touch their BARs.
Turn off IO/MEM decoding to prevent the devices from consuming address
space, since we can't read the BARs to find out what that address space
would be.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Tested-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/pci/probe.c |   14 ++++++++++++++
 include/linux/pci.h |    1 +
 2 files changed, 15 insertions(+)

--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -179,6 +179,9 @@ int __pci_read_base(struct pci_dev *dev,
 	u16 orig_cmd;
 	struct pci_bus_region region, inverted_region;
 
+	if (dev->non_compliant_bars)
+		return 0;
+
 	mask = type ? PCI_ROM_ADDRESS_MASK : ~0;
 
 	/* No printks while decoding is disabled! */
@@ -1171,6 +1174,7 @@ static void pci_msi_setup_pci_dev(struct
 int pci_setup_device(struct pci_dev *dev)
 {
 	u32 class;
+	u16 cmd;
 	u8 hdr_type;
 	int pos = 0;
 	struct pci_bus_region region;
@@ -1214,6 +1218,16 @@ int pci_setup_device(struct pci_dev *dev
 	/* device class may be changed after fixup */
 	class = dev->class >> 8;
 
+	if (dev->non_compliant_bars) {
+		pci_read_config_word(dev, PCI_COMMAND, &cmd);
+		if (cmd & (PCI_COMMAND_IO | PCI_COMMAND_MEMORY)) {
+			dev_info(&dev->dev, "device has non-compliant BARs; disabling IO/MEM decoding\n");
+			cmd &= ~PCI_COMMAND_IO;
+			cmd &= ~PCI_COMMAND_MEMORY;
+			pci_write_config_word(dev, PCI_COMMAND, cmd);
+		}
+	}
+
 	switch (dev->hdr_type) {		    /* header type */
 	case PCI_HEADER_TYPE_NORMAL:		    /* standard header */
 		if (class == PCI_CLASS_BRIDGE_PCI)
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -359,6 +359,7 @@ struct pci_dev {
 	unsigned int	io_window_1k:1;	/* Intel P2P bridge 1K I/O windows */
 	unsigned int	irq_managed:1;
 	unsigned int	has_secondary_link:1;
+	unsigned int	non_compliant_bars:1;	/* broken BARs; ignore them */
 	pci_dev_flags_t dev_flags;
 	atomic_t	enable_cnt;	/* pci_enable_device has been called */
 

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[PATCH 4.5 000/238] 4.5.1-stable review Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-04-10 23:00 +0200
  [PATCH 4.5 027/238] PCI: ACPI: IA64: fix IO port generic range check Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-04-10 23:00 +0200
  [PATCH 4.5 001/238] x86/microcode/intel: Make early loader look for builtin microcode too Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-04-10 23:00 +0200
  [PATCH 4.5 010/238] KVM: VMX: avoid guest hang on invalid invvpid instruction Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-04-10 23:00 +0200
  [PATCH 4.5 033/238] sg: fix dxferp in from_to case Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-04-10 23:00 +0200
  [PATCH 4.5 023/238] s390/cpumf: add missing lpp magic initialization Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-04-10 23:00 +0200
  [PATCH 4.5 024/238] s390/pci: enforce fmb page boundary rule Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-04-10 23:00 +0200
  [PATCH 4.5 025/238] pinctrl-bcm2835: Fix cut-and-paste error in "pull" parsing Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-04-10 23:00 +0200
  [PATCH 4.5 031/238] x86/iopl: Fix iopl capability check on Xen PV Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-04-10 23:00 +0200
  [PATCH 4.5 026/238] PCI: Disable IO/MEM decoding for devices with non-compliant BARs Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-04-10 23:00 +0200
    Re: [PATCH 4.5 026/238] PCI: Disable IO/MEM decoding for devices  with non-compliant BARs Ben Hutchings <ben@decadent.org.uk> - 2016-04-12 01:50 +0200
      Re: [PATCH 4.5 026/238] PCI: Disable IO/MEM decoding for devices  with non-compliant BARs Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-04-12 16:40 +0200
  [PATCH 4.5 022/238] s390: fix floating pointer register corruption (again) Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-04-10 23:00 +0200
  [PATCH 4.5 019/238] sched/preempt, sh: kmap_coherent relies on disabled preemption Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-04-10 23:00 +0200
  [PATCH 4.5 029/238] x86/apic: Fix suspicious RCU usage in smp_trace_call_function_interrupt() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-04-10 23:00 +0200
  [PATCH 4.5 021/238] EDAC, amd64_edac: Shift wrapping issue in f1x_get_norm_dct_addr() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-04-10 23:00 +0200
  Re: [PATCH 4.5 000/238] 4.5.1-stable review Guenter Roeck <linux@roeck-us.net> - 2016-04-11 08:50 +0200
    Re: [PATCH 4.5 000/238] 4.5.1-stable review Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-04-12 16:40 +0200
  Re: [PATCH 4.5 000/238] 4.5.1-stable review shuahkh <shuahkh@osg.sisa.samsung.com> - 2016-04-11 19:30 +0200
    Re: [PATCH 4.5 000/238] 4.5.1-stable review Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-04-12 08:50 +0200

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