[PATCH v3 bpf-next 08/11] bpftool: Document support for multi-split BTF

[Alan Maguire <alan.maguire@oracle.com>]

Document the ability to pass multiple levels of split BTF, using
"-B base-btf" options.

Signed-off-by: Alan Maguire <alan.maguire@oracle.com>
---
 tools/bpf/bpftool/Documentation/bpftool-btf.rst | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/tools/bpf/bpftool/Documentation/bpftool-btf.rst b/tools/bpf/bpftool/Documentation/bpftool-btf.rst
index cf75a7fa2d6b..c6dc445cd4a1 100644
--- a/tools/bpf/bpftool/Documentation/bpftool-btf.rst
+++ b/tools/bpf/bpftool/Documentation/bpftool-btf.rst
@@ -16,7 +16,7 @@ SYNOPSIS
 
 **bpftool** [*OPTIONS*] **btf** *COMMAND*
 
-*OPTIONS* := { |COMMON_OPTIONS| | { **-B** | **--base-btf** } }
+*OPTIONS* := { |COMMON_OPTIONS| | [{ **-B** | **--base-btf**} *FILE*]...  }
 
 *COMMANDS* := { **dump** | **help** }
 
@@ -87,7 +87,10 @@ OPTIONS
     objects for kernel modules. To avoid duplicating all kernel symbols
     required by modules, BTF objects for modules are "split", they are
     built incrementally on top of the kernel (vmlinux) BTF object. So the
-    base BTF reference should usually point to the kernel BTF.
+    base BTF reference should usually point to the kernel BTF.  Multiple
+    base BTF objects can be passed, where the first is assumed to be the
+    root BTF, followed by split BTF based upon it, followed by split
+    BTF based upon the first split BTF and so on.
 
     When the main BTF object to process (for example, the module BTF to
     dump) is passed as a *FILE*, bpftool attempts to autodetect the path
-- 
2.43.5