From 162b83bd5f1d7124e21da78bcf2685b9824d9ef0 Mon Sep 17 00:00:00 2001 From: Rui Wang Date: Wed, 17 Aug 2016 16:00:36 +0800 Subject: [PATCH] x86/ioapic: Fix lost IOAPIC resource after hot-removal and hotadd IOAPIC resource at 0xfecxxxxx gets lost from /proc/iomem after hot-removing and then hot-adding the IOAPIC device. After system boot, in /proc/iomem: fec00000-fecfffff : PNP0003:00 fec00000-fec003ff : IOAPIC 0 fec01000-fec013ff : IOAPIC 1 fec40000-fec403ff : IOAPIC 2 fec80000-fec803ff : IOAPIC 3 fecc0000-fecc03ff : IOAPIC 4 Then hot-remove IOAPIC 2 and hot-add it again: fec00000-fecfffff : PNP0003:00 fec00000-fec003ff : IOAPIC 0 fec01000-fec013ff : IOAPIC 1 fec80000-fec803ff : IOAPIC 3 fecc0000-fecc03ff : IOAPIC 4 The range at 0xfec40000 is lost from /proc/iomem - which is a bug. This bug happens because handle_ioapic_add() requests resources from either PCI config BAR or ACPI "_CRS", not both. But Intel platforms map the IOxAPIC registers both at the PCI config BAR (called MBAR, dynamic), and at the ACPI "_CRS" (called ABAR, static). The 0xfecX_YZ00 to 0xfecX_YZFF range appears in "_CRS" of each IOAPIC device. Both ranges should be claimed from /proc/iomem for exclusive use. Signed-off-by: Rui Wang Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: bhelgaas@google.com Cc: helgaas@kernel.org Cc: linux-acpi@vger.kernel.org Cc: linux-pci@vger.kernel.org Cc: rjw@rjwysocki.net Cc: tony.luck@intel.com Link: http://lkml.kernel.org/r/1471420837-31003-5-git-send-email-rui.y.wang@intel.com Signed-off-by: Ingo Molnar --- drivers/acpi/ioapic.c | 36 ++++++++++++++++++++---------------- 1 file changed, 20 insertions(+), 16 deletions(-) diff --git a/drivers/acpi/ioapic.c b/drivers/acpi/ioapic.c index 8ab6d42..ee20111 100644 --- a/drivers/acpi/ioapic.c +++ b/drivers/acpi/ioapic.c @@ -97,7 +97,7 @@ static acpi_status handle_ioapic_add(acpi_handle handle, u32 lvl, unsigned long long gsi_base; struct acpi_pci_ioapic *ioapic; struct pci_dev *dev = NULL; - struct resource *res = NULL; + struct resource *res = NULL, *pci_res = NULL, *crs_res; char *type = NULL; if (!acpi_is_ioapic(handle, &type)) @@ -137,23 +137,28 @@ static acpi_status handle_ioapic_add(acpi_handle handle, u32 lvl, pci_set_master(dev); if (pci_request_region(dev, 0, type)) goto exit_disable; - res = &dev->resource[0]; + pci_res = &dev->resource[0]; ioapic->pdev = dev; } else { pci_dev_put(dev); dev = NULL; + } - res = &ioapic->res; - acpi_walk_resources(handle, METHOD_NAME__CRS, setup_res, res); - if (res->flags == 0) { - acpi_handle_warn(handle, "failed to get resource\n"); - goto exit_free; - } else if (request_resource(&iomem_resource, res)) { - acpi_handle_warn(handle, "failed to insert resource\n"); - goto exit_free; - } + crs_res = &ioapic->res; + acpi_walk_resources(handle, METHOD_NAME__CRS, setup_res, crs_res); + if (crs_res->flags == 0) { + acpi_handle_warn(handle, "failed to get resource\n"); + goto exit_release; + } else if (request_resource(&iomem_resource, crs_res)) { + acpi_handle_warn(handle, "failed to insert resource\n"); + goto exit_release; } + /* try pci resource first, then "_CRS" resource */ + res = pci_res; + if (!res || !res->flags) + res = crs_res; + if (acpi_register_ioapic(handle, res->start, (u32)gsi_base)) { acpi_handle_warn(handle, "failed to register IOAPIC\n"); goto exit_release; @@ -174,14 +179,13 @@ done: exit_release: if (dev) pci_release_region(dev, 0); - else - release_resource(res); + if (ioapic->res.flags && ioapic->res.parent) + release_resource(&ioapic->res); exit_disable: if (dev) pci_disable_device(dev); exit_put: pci_dev_put(dev); -exit_free: kfree(ioapic); exit: mutex_unlock(&ioapic_list_lock); @@ -217,9 +221,9 @@ int acpi_ioapic_remove(struct acpi_pci_root *root) pci_release_region(ioapic->pdev, 0); pci_disable_device(ioapic->pdev); pci_dev_put(ioapic->pdev); - } else if (ioapic->res.flags && ioapic->res.parent) { - release_resource(&ioapic->res); } + if (ioapic->res.flags && ioapic->res.parent) + release_resource(&ioapic->res); list_del(&ioapic->list); kfree(ioapic); } -- 2.7.4