From 7d505758b1e556cdf65a5e451744fe0ae8063d17 Mon Sep 17 00:00:00 2001 From: "M. Vefa Bicakci" Date: Thu, 15 Aug 2019 21:41:39 -0400 Subject: [PATCH] platform/x86: intel_pmc_core: Do not ioremap RAM 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 Signed-off-by: Andy Shevchenko --- 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 c510d0d72475..3b6b8dcc4767 100644 --- a/drivers/platform/x86/intel_pmc_core.c +++ b/drivers/platform/x86/intel_pmc_core.c @@ -878,10 +878,14 @@ static int pmc_core_probe(struct platform_device *pdev) 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);