linux-stable/include/acpi/atomicio.h

#ifndef ACPI_ATOMIC_IO_H
#define ACPI_ATOMIC_IO_H

int acpi_pre_map_gar(struct acpi_generic_address *reg);
int acpi_post_unmap_gar(struct acpi_generic_address *reg);

int acpi_atomic_read(u64 *val, struct acpi_generic_address *reg);
int acpi_atomic_write(u64 val, struct acpi_generic_address *reg);

#endif
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 06:35:11 +00:00			`#ifndef ACPI_ATOMIC_IO_H`
			`#define ACPI_ATOMIC_IO_H`

			`int acpi_pre_map_gar(struct acpi_generic_address *reg);`
			`int acpi_post_unmap_gar(struct acpi_generic_address *reg);`

			`int acpi_atomic_read(u64 val, struct acpi_generic_address reg);`
			`int acpi_atomic_write(u64 val, struct acpi_generic_address *reg);`

			`#endif`