1What: /sys/firmware/gsmi 2Date: March 2011 3Contact: Mike Waychison <mikew@google.com> 4Description: 5 Some servers used internally at Google have firmware 6 that provides callback functionality via explicit SMI 7 triggers. Some of the callbacks are similar to those 8 provided by the EFI runtime services page, but due to 9 historical reasons this different entry-point has been 10 used. 11 12 The gsmi driver implements the kernel's abstraction for 13 these firmware callbacks. Currently, this functionality 14 is limited to handling the system event log and getting 15 access to EFI-style variables stored in nvram. 16 17 Layout: 18 19 /sys/firmware/gsmi/vars: 20 21 This directory has the same layout (and 22 underlying implementation as /sys/firmware/efi/vars. 23 See `Documentation/ABI/*/sysfs-firmware-efi-vars` 24 for more information on how to interact with 25 this structure. 26 27 /sys/firmware/gsmi/append_to_eventlog - write-only: 28 29 This file takes a binary blob and passes it onto 30 the firmware to be timestamped and appended to 31 the system eventlog. The binary format is 32 interpreted by the firmware and may change from 33 platform to platform. The only kernel-enforced 34 requirement is that the blob be prefixed with a 35 32bit host-endian type used as part of the 36 firmware call. 37 38 /sys/firmware/gsmi/clear_config - write-only: 39 40 Writing any value to this file will cause the 41 entire firmware configuration to be reset to 42 "factory defaults". Callers should assume that 43 a reboot is required for the configuration to be 44 cleared. 45 46 /sys/firmware/gsmi/clear_eventlog - write-only: 47 48 This file is used to clear out a portion/the 49 whole of the system event log. Values written 50 should be values between 1 and 100 inclusive (in 51 ASCII) representing the fraction of the log to 52 clear. Not all platforms support fractional 53 clearing though, and this writes to this file 54 will error out if the firmware doesn't like your 55 submitted fraction. 56 57 Callers should assume that a reboot is needed 58 for this operation to complete. 59