linux

ACPI, IO memory pre-mapping and atomic accessing Some ACPI IO accessing need to be done in atomic context. For example, APEI ERST operations may be used for permanent storage in hardware error handler. That is, it may be called in atomic contexts such as IRQ or NMI, etc. And, ERST/EINJ implement their operations via IO memory/port accessing. But the IO memory accessing method provided by ACPI (acpi_read/acpi_write) maps the IO memory during it is accessed, so it can not be used in atomic context. To solve the issue, the IO memory should be pre-mapped during EINJ/ERST initializing. A linked list is used to record which memory area has been mapped, when memory is accessed in hardware error handler, search the linked list for the mapped virtual address from the given physical address. Signed-off-by: Huang Ying <ying.huang@intel.com> Signed-off-by: Andi Kleen <ak@linux.intel.com> Signed-off-by: Len Brown <len.brown@intel.com> 2010-05-18 14:35:11 +08:00