Documentation/ABI/testing/sysfs-bus-coreboot
Source file repositories/reference/linux-study-clean/Documentation/ABI/testing/sysfs-bus-coreboot
File Facts
- System
- Linux kernel
- Corpus path
Documentation/ABI/testing/sysfs-bus-coreboot- Extension
[no extension]- Size
- 1716 bytes
- Lines
- 46
- Domain
- Support Tooling And Documentation
- Bucket
- Documentation
- Inferred role
- Support Tooling And Documentation: Documentation
- Status
- atlas-only
Why This File Exists
Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.
- Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.
Dependency Surface
- No C-style include directives detected by the generator.
Detected Declarations
- No top-level syscall, struct, function, initcall, or export declaration detected by the generator.
Annotated Snippet
What: /sys/bus/coreboot
Date: August 2022
Contact: Jack Rosenthal <jrosenth@chromium.org>
Description:
The coreboot bus provides a variety of virtual devices used to
access data structures created by the Coreboot BIOS.
What: /sys/bus/coreboot/devices/cbmem-<id>
Date: August 2022
Contact: Jack Rosenthal <jrosenth@chromium.org>
Description:
CBMEM is a downwards-growing memory region created by Coreboot,
and contains tagged data structures to be shared with payloads
in the boot process and the OS. Each CBMEM entry is given a
directory in /sys/bus/coreboot/devices based on its id.
A list of ids known to Coreboot can be found in the coreboot
source tree at
``src/commonlib/bsd/include/commonlib/bsd/cbmem_id.h``.
What: /sys/bus/coreboot/devices/cbmem-<id>/address
Date: August 2022
Contact: Jack Rosenthal <jrosenth@chromium.org>
Description:
This is the physical memory address that the CBMEM entry's data
begins at, in hexadecimal (e.g., ``0x76ffe000``).
What: /sys/bus/coreboot/devices/cbmem-<id>/size
Date: August 2022
Contact: Jack Rosenthal <jrosenth@chromium.org>
Description:
This is the size of the CBMEM entry's data, in hexadecimal
(e.g., ``0x1234``).
What: /sys/bus/coreboot/devices/cbmem-<id>/mem
Date: August 2022
Contact: Jack Rosenthal <jrosenth@chromium.org>
Description:
A file exposing read/write access to the entry's data. Note
that this file does not support mmap(), as coreboot
does not guarantee that the data will be page-aligned.
The mode of this file is 0600. While there shouldn't be
anything security-sensitive contained in CBMEM, read access
requires root privileges given this is exposing a small subset
of physical memory.Annotation
- Atlas domain: Support Tooling And Documentation / Documentation.
- Implementation status: atlas-only.
Implementation Notes
- This generated page is the file-by-file coverage layer; curated subsystem chapters should link here when they synthesize a multi-file control flow.
- Core OS pages should be promoted from atlas-only to deep-reviewed when they explain data structures, invariants, locking, lifecycle, and C implementation snippets.
- Driver-family pages are intentionally pattern-oriented unless they are part of the selected PCIe/NVMe representative device path.