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 <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>

0 files changed, 0 insertions, 0 deletions