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由 Myron Stowe 提交于
During ACPI initialization, pre-map fixed hardware registers that are accessed during ACPI's 'system event' related IRQ handing. ACPI's 'system event' handing accesses specific fixed hardware registers; namely PM1a event, PM1b event, GPE0, and GPE1 register blocks which are declared within the FADT. If these registers are backed by MMIO, as opposed to I/O port space, accessing them within interrupt context will cause a panic as acpi_os_read_memory() depends on ioremap() in such cases - BZ 18012. By utilizing the functionality provided in the previous two patches - ACPI: Maintain a list of ACPI memory mapped I/O remappings, and, ACPI: Add interfaces for ioremapping/iounmapping ACPI registers - accesses to ACPI MMIO areas will now be safe from within interrupt contexts (IRQ and/or NMI) provided the area was pre-mapped. This solves BZ 18012. ACPI "System Event" reference(s): ACPI Specification, Revision 4.0, Section 3 "ACPI Overview", 3.8 "System Events", 5.6 "ACPI Event Programming Model". Reference: https://bugzilla.kernel.org/show_bug.cgi?id=18012 Reported-by: <bjorn.helgaas@hp.com> Signed-off-by: NMyron Stowe <myron.stowe@hp.com> Signed-off-by: NLen Brown <len.brown@intel.com>
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