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platform/x86: hp-bioscfg: Documentation

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Update sysfs-class-firmware-attributes with hp-bioscfg information

HP BIOS Configuration driver purpose is to provide a driver supporting
the latest sysfs class firmware attributes framework allowing the user
to change BIOS settings and security solutions on HP Inc.’s commercial
notebooks.

Signed-off-by: Jorge Lopez <jorge.lopez2@hp.com>
Reviewed-by: Thomas Weißschuh <linux@weissschuh.net>
Link: https://lore.kernel.org/r/20230608163319.18934-2-jorge.lopez2@hp.com
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
This commit is contained in:
Jorge Lopez 2023-06-08 11:33:07 -05:00 committed by Hans de Goede
parent 06c2afb862
commit 00d4b35212
1 changed files with 99 additions and 2 deletions
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101
Documentation/ABI/testing/sysfs-class-firmware-attributes
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@ -22,6 +22,11 @@ Description:
- integer: a range of numerical values
- string
HP specific types
-----------------
- ordered-list - a set of ordered list valid values
All attribute types support the following values:
current_value:
@ -126,6 +131,21 @@ Description:
value will not be effective through sysfs until this rule is
met.
HP specific class extensions
------------------------------
On HP systems the following additional attributes are available:
"ordered-list"-type specific properties:
elements:
A file that can be read to obtain the possible
list of values of the <attr>. Values are separated using
semi-colon (``;``) and listed according to their priority.
An element listed first has the highest priority. Writing
the list in a different order to current_value alters
the priority order for the particular attribute.
What: /sys/class/firmware-attributes/*/authentication/
Date: February 2021
KernelVersion: 5.11
@ -206,7 +226,7 @@ Description:
Drivers may emit a CHANGE uevent when a password is set or unset
userspace may check it again.
On Dell and Lenovo systems, if Admin password is set, then all BIOS attributes
On Dell, Lenovo and HP systems, if Admin password is set, then all BIOS attributes
require password validation.
On Lenovo systems if you change the Admin password the new password is not active until
the next boot.
@ -296,6 +316,15 @@ Description:
echo "signature" > authentication/Admin/signature
echo "password" > authentication/Admin/certificate_to_password
HP specific class extensions
--------------------------------
On HP systems the following additional settings are available:
role: enhanced-bios-auth:
This role is specific to Secure Platform Management (SPM) attribute.
It requires configuring an endorsement (kek) and signing certificate (sk).
What: /sys/class/firmware-attributes/*/attributes/pending_reboot
Date: February 2021
@ -311,7 +340,7 @@ Description:
== =========================================
0 All BIOS attributes setting are current
1 A reboot is necessary to get pending BIOS
attribute changes applied
attribute changes applied
== =========================================
Note, userspace applications need to follow below steps for efficient
@ -364,3 +393,71 @@ Description:
use it to enable extra debug attributes or BIOS features for testing purposes.
Note that any changes to this attribute requires a reboot for changes to take effect.
HP specific class extensions - Secure Platform Manager (SPM)
--------------------------------
What: /sys/class/firmware-attributes/*/authentication/SPM/kek
Date: March 2023
KernelVersion: 5.18
Contact: "Jorge Lopez" <jorge.lopez2@hp.com>
Description:
'kek' Key-Encryption-Key is a write-only file that can be used to configure the
RSA public key that will be used by the BIOS to verify
signatures when setting the signing key. When written,
the bytes should correspond to the KEK certificate
(x509 .DER format containing an OU). The size of the
certificate must be less than or equal to 4095 bytes.
What: /sys/class/firmware-attributes/*/authentication/SPM/sk
Date: March 2023
KernelVersion: 5.18
Contact: "Jorge Lopez" <jorge.lopez2@hp.com>
Description:
'sk' Signature Key is a write-only file that can be used to configure the RSA
public key that will be used by the BIOS to verify signatures
when configuring BIOS settings and security features. When
written, the bytes should correspond to the modulus of the
public key. The exponent is assumed to be 0x10001.
What: /sys/class/firmware-attributes/*/authentication/SPM/status
Date: March 2023
KernelVersion: 5.18
Contact: "Jorge Lopez" <jorge.lopez2@hp.com>
Description:
'status' is a read-only file that returns ASCII text in JSON format reporting
the status information.
"State": "not provisioned | provisioned | provisioning in progress",
"Version": "Major.Minor",
"Nonce": <16-bit unsigned number display in base 10>,
"FeaturesInUse": <16-bit unsigned number display in base 10>,
"EndorsementKeyMod": "<256 bytes in base64>",
"SigningKeyMod": "<256 bytes in base64>"
What: /sys/class/firmware-attributes/*/attributes/Sure_Start/audit_log_entries
Date: March 2023
KernelVersion: 5.18
Contact: "Jorge Lopez" <jorge.lopez2@hp.com>
Description:
'audit_log_entries' is a read-only file that returns the events in the log.
Audit log entry format
Byte 0-15: Requested Audit Log entry (Each Audit log is 16 bytes)
Byte 16-127: Unused
What: /sys/class/firmware-attributes/*/attributes/Sure_Start/audit_log_entry_count
Date: March 2023
KernelVersion: 5.18
Contact: "Jorge Lopez" <jorge.lopez2@hp.com>
Description:
'audit_log_entry_count' is a read-only file that returns the number of existing
audit log events available to be read. Values are separated using comma. (``,``)
[No of entries],[log entry size],[Max number of entries supported]
log entry size identifies audit log size for the current BIOS version.
The current size is 16 bytes but it can be up to 128 bytes long in future BIOS
versions.