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74c5b31c MW |
1 | What: /sys/firmware/gsmi |
2 | Date: March 2011 | |
3 | Contact: Mike Waychison <mikew@google.com> | |
4 | Description: | |
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. |