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+What: /sys/firmware/gsmi
+Date: March 2011
+Contact: Mike Waychison <mikew@google.com>
+Description:
+ Some servers used internally at Google have firmware
+ that provides callback functionality via explicit SMI
+ triggers. Some of the callbacks are similar to those
+ provided by the EFI runtime services page, but due to
+ historical reasons this different entry-point has been
+ used.
+
+ The gsmi driver implements the kernel's abstraction for
+ these firmware callbacks. Currently, this functionality
+ is limited to handling the system event log and getting
+ access to EFI-style variables stored in nvram.
+
+ Layout:
+
+ /sys/firmware/gsmi/vars:
+
+ This directory has the same layout (and
+ underlying implementation as /sys/firmware/efi/vars.
+ See Documentation/ABI/*/sysfs-firmware-efi-vars
+ for more information on how to interact with
+ this structure.
+
+ /sys/firmware/gsmi/append_to_eventlog - write-only:
+
+ This file takes a binary blob and passes it onto
+ the firmware to be timestamped and appended to
+ the system eventlog. The binary format is
+ interpreted by the firmware and may change from
+ platform to platform. The only kernel-enforced
+ requirement is that the blob be prefixed with a
+ 32bit host-endian type used as part of the
+ firmware call.
+
+ /sys/firmware/gsmi/clear_config - write-only:
+
+ Writing any value to this file will cause the
+ entire firmware configuration to be reset to
+ "factory defaults". Callers should assume that
+ a reboot is required for the configuration to be
+ cleared.
+
+ /sys/firmware/gsmi/clear_eventlog - write-only:
+
+ This file is used to clear out a portion/the
+ whole of the system event log. Values written
+ should be values between 1 and 100 inclusive (in
+ ASCII) representing the fraction of the log to
+ clear. Not all platforms support fractional
+ clearing though, and this writes to this file
+ will error out if the firmware doesn't like your
+ submitted fraction.
+
+ Callers should assume that a reboot is needed
+ for this operation to complete.