tools/lib/bpf/features.c

File Facts

System

Linux kernel

Corpus path

tools/lib/bpf/features.c

Extension

.c

Size

20629 bytes

Lines

736

Domain

Support Tooling And Documentation

Bucket

tools

Inferred role

Support Tooling And Documentation: implementation source

Status

source implementation candidate

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.
• Defines or uses C structs; map object ownership, embedded links, reference counts, and lock ownership.

Dependency Surface

• linux/kernel.h
• linux/filter.h
• bpf.h
• libbpf.h
• libbpf_common.h
• libbpf_internal.h

Detected Declarations

• function ptr_to_u64
• function probe_fd
• function probe_kern_prog_name
• function probe_kern_global_data
• function probe_kern_btf
• function probe_kern_btf_func
• function probe_kern_btf_func_global
• function probe_kern_btf_datasec
• function probe_kern_btf_qmark_datasec
• function probe_kern_btf_float
• function probe_kern_btf_decl_tag
• function probe_kern_btf_type_tag
• function probe_kern_array_mmap
• function probe_kern_exp_attach_type
• function probe_kern_probe_read_kernel
• function probe_prog_bind_map
• function probe_module_btf
• function probe_perf_link
• function probe_uprobe_multi_link
• function probe_kern_bpf_cookie
• function probe_kern_btf_enum64
• function probe_kern_arg_ctx_tag
• function probe_ldimm64_full_range_off
• function probe_uprobe_syscall
• function probe_uprobe_syscall
• function probe_kern_btf_layout
• function probe_bpf_syscall_common_attrs
• function feat_supported

Annotated Snippet

if (ret > 0) {
			WRITE_ONCE(cache->res[feat_id], FEAT_SUPPORTED);
		} else if (ret == 0) {
			WRITE_ONCE(cache->res[feat_id], FEAT_MISSING);
		} else {
			pr_warn("Detection of kernel %s support failed: %s\n",
				feat->desc, errstr(ret));
			WRITE_ONCE(cache->res[feat_id], FEAT_MISSING);
		}
	}

	return READ_ONCE(cache->res[feat_id]) == FEAT_SUPPORTED;
}

Annotation

• Immediate include surface: `linux/kernel.h`, `linux/filter.h`, `bpf.h`, `libbpf.h`, `libbpf_common.h`, `libbpf_internal.h`.
• Detected declarations: `function ptr_to_u64`, `function probe_fd`, `function probe_kern_prog_name`, `function probe_kern_global_data`, `function probe_kern_btf`, `function probe_kern_btf_func`, `function probe_kern_btf_func_global`, `function probe_kern_btf_datasec`, `function probe_kern_btf_qmark_datasec`, `function probe_kern_btf_float`.
• Atlas domain: Support Tooling And Documentation / tools.
• Implementation status: source implementation candidate.

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.