tools: bpftool: add documentation

Add documentation for bpftool.  Separate files for each subcommand.
Use rst format.  Documentation is compiled into man pages using
rst2man.
Signed-off-by: David Beckett <david.beckett@netronome.com>
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

tools/bpf/bpftool/Documentation/Makefile

+include ../../../scripts/Makefile.include
+include ../../../scripts/utilities.mak
+
+INSTALL ?= install
+RM ?= rm -f
+
+# Make the path relative to DESTDIR, not prefix
+ifndef DESTDIR
+prefix?=$(HOME)
+endif
+mandir ?= $(prefix)/share/man
+man8dir = $(mandir)/man8
+
+MAN8_RST = $(wildcard *.rst)
+
+_DOC_MAN8 = $(patsubst %.rst,%.8,$(MAN8_RST))
+DOC_MAN8 = $(addprefix $(OUTPUT),$(_DOC_MAN8))
+
+man: man8
+man8: $(DOC_MAN8)
+
+$(OUTPUT)%.8: %.rst
+	rst2man $< > $@
+
+clean:
+	$(call QUIET_CLEAN, Documentation) $(RM) $(DOC_MAN8)
+
+install: man
+	$(call QUIET_INSTALL, Documentation-man) \
+		$(INSTALL) -d -m 755 $(DESTDIR)$(man8dir); \
+		$(INSTALL) -m 644 $(DOC_MAN8) $(DESTDIR)$(man8dir);
+
+.PHONY: man man8 clean install
+.DEFAULT_GOAL := man

tools/bpf/bpftool/Documentation/bpftool-map.rst

+================
+bpftool-map
+================
+-------------------------------------------------------------------------------
+tool for inspection and simple manipulation of eBPF maps
+-------------------------------------------------------------------------------
+
+:Manual section: 8
+
+SYNOPSIS
+========
+
+	**bpftool** **map** *COMMAND*
+
+	*COMMANDS* :=
+	{ show | dump | update | lookup | getnext | delete | pin | help }
+
+MAP COMMANDS
+=============
+
+|	**bpftool** map show   [*MAP*]
+|	**bpftool** map dump    *MAP*
+|	**bpftool** map update  *MAP*  key *BYTES*   value *VALUE* [*UPDATE_FLAGS*]
+|	**bpftool** map lookup  *MAP*  key *BYTES*
+|	**bpftool** map getnext *MAP* [key *BYTES*]
+|	**bpftool** map delete  *MAP*  key *BYTES*
+|	**bpftool** map pin     *MAP*  *FILE*
+|	**bpftool** map help
+|
+|	*MAP* := { id MAP_ID | pinned FILE }
+|	*VALUE* := { BYTES | MAP | PROGRAM }
+|	*UPDATE_FLAGS* := { any | exist | noexist }
+
+DESCRIPTION
+===========
+	**bpftool map show**   [*MAP*]
+		  Show information about loaded maps.  If *MAP* is specified
+		  show information only about given map, otherwise list all
+		  maps currently loaded on the system.
+
+		  Output will start with map ID followed by map type and
+		  zero or more named attributes (depending on kernel version).
+
+	**bpftool map dump**    *MAP*
+		  Dump all entries in a given *MAP*.
+
+	**bpftool map update**  *MAP*  **key** *BYTES*   **value** *VALUE* [*UPDATE_FLAGS*]
+		  Update map entry for a given *KEY*.
+
+		  *UPDATE_FLAGS* can be one of: **any** update existing entry
+		  or add if doesn't exit; **exist** update only if entry already
+		  exists; **noexist** update only if entry doesn't exist.
+
+	**bpftool map lookup**  *MAP*  **key** *BYTES*
+		  Lookup **key** in the map.
+
+	**bpftool map getnext** *MAP* [**key** *BYTES*]
+		  Get next key.  If *key* is not specified, get first key.
+
+	**bpftool map delete**  *MAP*  **key** *BYTES*
+		  Remove entry from the map.
+
+	**bpftool map pin**     *MAP*  *FILE*
+		  Pin map *MAP* as *FILE*.
+
+		  Note: *FILE* must be located in *bpffs* mount.
+
+	**bpftool map help**
+		  Print short help message.
+
+EXAMPLES
+========
+**# bpftool map show**
+::
+
+  10: hash  name some_map  flags 0x0
+	key 4B  value 8B  max_entries 2048  memlock 167936B
+
+**# bpftool map update id 10 key 13 00 07 00 value 02 00 00 00 01 02 03 04**
+
+**# bpftool map lookup id 10 key 0 1 2 3**
+
+::
+
+  key: 00 01 02 03 value: 00 01 02 03 04 05 06 07
+
+
+**# bpftool map dump id 10**
+::
+
+  key: 00 01 02 03  value: 00 01 02 03 04 05 06 07
+  key: 0d 00 07 00  value: 02 00 00 00 01 02 03 04
+  Found 2 elements
+
+**# bpftool map getnext id 10 key 0 1 2 3**
+::
+
+  key:
+  00 01 02 03
+  next key:
+  0d 00 07 00
+
+|
+| **# mount -t bpf none /sys/fs/bpf/**
+| **# bpftool map pin id 10 /sys/fs/bpf/map**
+| **# bpftool map del pinned /sys/fs/bpf/map key 13 00 07 00**
+
+SEE ALSO
+========
+	**bpftool**\ (8), **bpftool-prog**\ (8)

tools/bpf/bpftool/Documentation/bpftool-prog.rst

+================
+bpftool-prog
+================
+-------------------------------------------------------------------------------
+tool for inspection and simple manipulation of eBPF progs
+-------------------------------------------------------------------------------
+
+:Manual section: 8
+
+SYNOPSIS
+========
+
+|	**bpftool** prog show [*PROG*]
+|	**bpftool** prog dump xlated *PROG*  file *FILE*
+|	**bpftool** prog dump jited  *PROG* [file *FILE*] [opcodes]
+|	**bpftool** prog pin *PROG* *FILE*
+|	**bpftool** prog help
+|
+|	*PROG* := { id *PROG_ID* | pinned *FILE* | tag *PROG_TAG* }
+
+DESCRIPTION
+===========
+	**bpftool prog show** [*PROG*]
+		  Show information about loaded programs.  If *PROG* is
+		  specified show information only about given program, otherwise
+		  list all programs currently loaded on the system.
+
+		  Output will start with program ID followed by program type and
+		  zero or more named attributes (depending on kernel version).
+
+	**bpftool prog dump xlated** *PROG*  **file** *FILE*
+		  Dump eBPF instructions of the program from the kernel to a
+		  file.
+
+	**bpftool prog dump jited**  *PROG* [**file** *FILE*] [**opcodes**]
+		  Dump jited image (host machine code) of the program.
+		  If *FILE* is specified image will be written to a file,
+		  otherwise it will be disassembled and printed to stdout.
+
+		  **opcodes** controls if raw opcodes will be printed.
+
+	**bpftool prog pin** *PROG* *FILE*
+		  Pin program *PROG* as *FILE*.
+
+		  Note: *FILE* must be located in *bpffs* mount.
+
+	**bpftool prog help**
+		  Print short help message.
+
+EXAMPLES
+========
+**# bpftool prog show**
+::
+
+  10: xdp  name some_prog  tag 00:5a:3d:21:23:62:0c:8b
+	loaded_at Sep 29/20:11  uid 0
+	xlated 528B  jited 370B  memlock 4096B  map_ids 10
+
+|
+| **# bpftool prog dump xlated id 10 file /tmp/t**
+| **# ls -l /tmp/t**
+|   -rw------- 1 root root 560 Jul 22 01:42 /tmp/t
+
+|
+| **# bpftool prog dum jited pinned /sys/fs/bpf/prog**
+
+::
+
+    push   %rbp
+    mov    %rsp,%rbp
+    sub    $0x228,%rsp
+    sub    $0x28,%rbp
+    mov    %rbx,0x0(%rbp)
+
+
+
+SEE ALSO
+========
+	**bpftool**\ (8), **bpftool-map**\ (8)

tools/bpf/bpftool/Documentation/bpftool.rst

+================
+BPFTOOL
+================
+-------------------------------------------------------------------------------
+tool for inspection and simple manipulation of eBPF programs and maps
+-------------------------------------------------------------------------------
+
+:Manual section: 8
+
+SYNOPSIS
+========
+
+	**bpftool** *OBJECT* { *COMMAND* | help }
+
+	**bpftool** batch file *FILE*
+
+	*OBJECT* := { **map** | **program** }
+
+	*MAP-COMMANDS* :=
+	{ show | dump | update | lookup | getnext | delete | pin | help }
+
+	*PROG-COMMANDS* := { show | dump jited | dump xlated | pin | help }
+
+DESCRIPTION
+===========
+	*bpftool* allows for inspection and simple modification of BPF objects
+	on the system.
+
+	Note that format of the output of all tools is not guaranteed to be
+	stable and should not be depended upon.
+
+SEE ALSO
+========
+	**bpftool-map**\ (8), **bpftool-prog**\ (8)

tools/bpf/bpftool/Makefile

@@ -74,6 +74,12 @@ clean: $(LIBBPF)-clean
 install:
 	install $(OUTPUT)bpftool $(prefix)/sbin/bpftool
 
+doc:
+	$(Q)$(MAKE) -C Documentation/
+
+doc-install:
+	$(Q)$(MAKE) -C Documentation/ install
+
 FORCE:
 
 .PHONY: all clean FORCE