From: "M. Vefa Bicakci" m.v.b@runbox.com
[ Upstream commit 7d505758b1e556cdf65a5e451744fe0ae8063d17 ]
On a Xen-based PVH virtual machine with more than 4 GiB of RAM, intel_pmc_core fails initialization with the following warning message from the kernel, indicating that the driver is attempting to ioremap RAM:
ioremap on RAM at 0x00000000fe000000 - 0x00000000fe001fff WARNING: CPU: 1 PID: 434 at arch/x86/mm/ioremap.c:186 __ioremap_caller.constprop.0+0x2aa/0x2c0 ... Call Trace: ? pmc_core_probe+0x87/0x2d0 [intel_pmc_core] pmc_core_probe+0x87/0x2d0 [intel_pmc_core]
This issue appears to manifest itself because of the following fallback mechanism in the driver:
if (lpit_read_residency_count_address(&slp_s0_addr)) pmcdev->base_addr = PMC_BASE_ADDR_DEFAULT;
The validity of address PMC_BASE_ADDR_DEFAULT (i.e., 0xFE000000) is not verified by the driver, which is what this patch introduces. With this patch, if address PMC_BASE_ADDR_DEFAULT is in RAM, then the driver will not attempt to ioremap the aforementioned address.
Signed-off-by: M. Vefa Bicakci m.v.b@runbox.com Signed-off-by: Andy Shevchenko andriy.shevchenko@linux.intel.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/platform/x86/intel_pmc_core.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/drivers/platform/x86/intel_pmc_core.c b/drivers/platform/x86/intel_pmc_core.c index 088d1c2047e6b..36bd2545afb62 100644 --- a/drivers/platform/x86/intel_pmc_core.c +++ b/drivers/platform/x86/intel_pmc_core.c @@ -685,10 +685,14 @@ static int __init pmc_core_probe(void) if (pmcdev->map == &spt_reg_map && !pci_dev_present(pmc_pci_ids)) pmcdev->map = &cnp_reg_map;
- if (lpit_read_residency_count_address(&slp_s0_addr)) + if (lpit_read_residency_count_address(&slp_s0_addr)) { pmcdev->base_addr = PMC_BASE_ADDR_DEFAULT; - else + + if (page_is_ram(PHYS_PFN(pmcdev->base_addr))) + return -ENODEV; + } else { pmcdev->base_addr = slp_s0_addr - pmcdev->map->slp_s0_offset; + }
pmcdev->regbase = ioremap(pmcdev->base_addr, pmcdev->map->regmap_length);