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PNP: Work around BIOS defects in Intel MCH area reporting

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Work around BIOSes that don't report the entire Intel MCH area.

MCHBAR is not an architected PCI BAR, so MCH space is usually reported as a
PNP0C02 resource.  The MCH space was once 16KB, but is 32KB in newer parts.
Some BIOSes still report a PNP0C02 resource that is only 16KB, which means
the rest of the MCH space is consumed but unreported.

This can cause resource map sanity check warnings or (theoretically) a
device conflict if we assigned the unreported space to another device.

The Intel perf event uncore driver tripped over this when it claimed the
MCH region:

  resource map sanity check conflict: 0xfed10000 0xfed15fff 0xfed10000 0xfed13fff pnp 00:01
  Info: mapping multiple BARs. Your kernel is fine.

To prevent this, if we find a PNP0C02 resource that covers part of the MCH
space, extend it to cover the entire space.

References: http://lkml.kernel.org/r/20140224162400.GE16457@pd.tnic
Reported-and-tested-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Borislav Petkov <bp@suse.de>
Acked-by: Stephane Eranian <eranian@google.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Bjorn Helgaas 2014-04-23 10:21:06 -06:00 committed by Rafael J. Wysocki
parent a798c10faf
commit cb171f7abb
1 changed files with 79 additions and 0 deletions
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79
drivers/pnp/quirks.c
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@ -15,6 +15,7 @@
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/pci.h>
#include <linux/string.h>
#include <linux/slab.h>
#include <linux/pnp.h>
@ -334,6 +335,81 @@ static void quirk_amd_mmconfig_area(struct pnp_dev *dev)
}
#endif
#ifdef CONFIG_X86
/* Device IDs of parts that have 32KB MCH space */
static const unsigned int mch_quirk_devices[] = {
0x0154, /* Ivy Bridge */
0x0c00, /* Haswell */
};
static struct pci_dev *get_intel_host(void)
{
int i;
struct pci_dev *host;
for (i = 0; i < ARRAY_SIZE(mch_quirk_devices); i++) {
host = pci_get_device(PCI_VENDOR_ID_INTEL, mch_quirk_devices[i],
NULL);
if (host)
return host;
}
return NULL;
}
static void quirk_intel_mch(struct pnp_dev *dev)
{
struct pci_dev *host;
u32 addr_lo, addr_hi;
struct pci_bus_region region;
struct resource mch;
struct pnp_resource *pnp_res;
struct resource *res;
host = get_intel_host();
if (!host)
return;
/*
* MCHBAR is not an architected PCI BAR, so MCH space is usually
* reported as a PNP0C02 resource. The MCH space was originally
* 16KB, but is 32KB in newer parts. Some BIOSes still report a
* PNP0C02 resource that is only 16KB, which means the rest of the
* MCH space is consumed but unreported.
*/
/*
* Read MCHBAR for Host Member Mapped Register Range Base
* https://www-ssl.intel.com/content/www/us/en/processors/core/4th-gen-core-family-desktop-vol-2-datasheet
* Sec 3.1.12.
*/
pci_read_config_dword(host, 0x48, &addr_lo);
region.start = addr_lo & ~0x7fff;
pci_read_config_dword(host, 0x4c, &addr_hi);
region.start |= (u64) addr_hi << 32;
region.end = region.start + 32*1024 - 1;
memset(&mch, 0, sizeof(mch));
mch.flags = IORESOURCE_MEM;
pcibios_bus_to_resource(host->bus, &mch, &region);
list_for_each_entry(pnp_res, &dev->resources, list) {
res = &pnp_res->res;
if (res->end < mch.start || res->start > mch.end)
continue; /* no overlap */
if (res->start == mch.start && res->end == mch.end)
continue; /* exact match */
dev_info(&dev->dev, FW_BUG "PNP resource %pR covers only part of %s Intel MCH; extending to %pR\n",
res, pci_name(host), &mch);
res->start = mch.start;
res->end = mch.end;
break;
}
pci_dev_put(host);
}
#endif
/*
* PnP Quirks
* Cards or devices that need some tweaking due to incomplete resource info
@ -363,6 +439,9 @@ static struct pnp_fixup pnp_fixups[] = {
{"PNP0c02", quirk_system_pci_resources},
#ifdef CONFIG_AMD_NB
{"PNP0c01", quirk_amd_mmconfig_area},
#endif
#ifdef CONFIG_X86
{"PNP0c02", quirk_intel_mch},
#endif
{""}
};