Commits
Rui Wang committed 162b83bd5f1
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 <rui.y.wang@intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> 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 <mingo@kernel.org>