tools/bpf: Remove bpf-helpers from bpftool docs

This logic is used for validating the manual pages from selftests, so
move the infra under tools/testing/selftests/bpf/ and rely on selftests
for validation rather than tying it into the bpftool build.

Signed-off-by: Joe Stringer <joe@cilium.io>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Reviewed-by: Quentin Monnet <quentin@isovalent.com>
Acked-by: Toke Høiland-Jørgensen <toke@redhat.com>
Link: https://lore.kernel.org/bpf/20210302171947.2268128-12-joe@cilium.io

5 files changed, 91 insertions, 26 deletions

diff --git a/tools/testing/selftests/bpf/.gitignore b/tools/testing/selftests/bpf/.gitignore
index c0c48fdb9ac1..a0d5ec3cfc24 100644
--- a/tools/testing/selftests/bpf/.gitignore
+++ b/tools/testing/selftests/bpf/.gitignore
@@ -1,4 +1,5 @@
 # SPDX-License-Identifier: GPL-2.0-only
+bpf-helpers*
 test_verifier
 test_maps
 test_lru_map
diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile
index a81af15e4ded..b5827464c6b5 100644
--- a/tools/testing/selftests/bpf/Makefile
+++ b/tools/testing/selftests/bpf/Makefile
@@ -68,6 +68,7 @@ TEST_PROGS := test_kmod.sh \
 	test_bpftool_build.sh \
 	test_bpftool.sh \
 	test_bpftool_metadata.sh \
+	test_docs_build.sh \
 	test_xsk.sh
 
 TEST_PROGS_EXTENDED := with_addr.sh \
@@ -103,6 +104,7 @@ override define CLEAN
 	$(call msg,CLEAN)
 	$(Q)$(RM) -r $(TEST_GEN_PROGS) $(TEST_GEN_PROGS_EXTENDED) $(TEST_GEN_FILES) $(EXTRA_CLEAN)
 	$(Q)$(MAKE) -C bpf_testmod clean
+	$(Q)$(MAKE) docs-clean
 endef
 
 include ../lib.mk
@@ -180,6 +182,7 @@ $(OUTPUT)/runqslower: $(BPFOBJ) | $(DEFAULT_BPFTOOL)
 		    cp $(SCRATCH_DIR)/runqslower $@
 
 $(TEST_GEN_PROGS) $(TEST_GEN_PROGS_EXTENDED): $(OUTPUT)/test_stub.o $(BPFOBJ)
+$(TEST_GEN_FILES): docs
 
 $(OUTPUT)/test_dev_cgroup: cgroup_helpers.c
 $(OUTPUT)/test_skb_cgroup_id_user: cgroup_helpers.c
@@ -200,11 +203,16 @@ $(DEFAULT_BPFTOOL): $(wildcard $(BPFTOOLDIR)/*.[ch] $(BPFTOOLDIR)/Makefile)    \
 		    CC=$(HOSTCC) LD=$(HOSTLD)				       \
 		    OUTPUT=$(HOST_BUILD_DIR)/bpftool/			       \
 		    prefix= DESTDIR=$(HOST_SCRATCH_DIR)/ install
-	$(Q)mkdir -p $(BUILD_DIR)/bpftool/Documentation
-	$(Q)RST2MAN_OPTS="--exit-status=1" $(MAKE) $(submake_extras)	       \
-		    -C $(BPFTOOLDIR)/Documentation			       \
-		    OUTPUT=$(BUILD_DIR)/bpftool/Documentation/		       \
-		    prefix= DESTDIR=$(SCRATCH_DIR)/ install
+
+docs:
+	$(Q)RST2MAN_OPTS="--exit-status=1" $(MAKE) $(submake_extras)	\
+	            -f Makefile.docs					\
+	            prefix= OUTPUT=$(OUTPUT)/ DESTDIR=$(OUTPUT)/ $@
+
+docs-clean:
+	$(Q)$(MAKE) $(submake_extras)					\
+	            -f Makefile.docs					\
+	            prefix= OUTPUT=$(OUTPUT)/ DESTDIR=$(OUTPUT)/ $@
 
 $(BPFOBJ): $(wildcard $(BPFDIR)/*.[ch] $(BPFDIR)/Makefile)		       \
 	   ../../../include/uapi/linux/bpf.h                                   \
@@ -477,3 +485,5 @@ EXTRA_CLEAN := $(TEST_CUSTOM_PROGS) $(SCRATCH_DIR) $(HOST_SCRATCH_DIR)	\
 	prog_tests/tests.h map_tests/tests.h verifier/tests.h		\
 	feature								\
 	$(addprefix $(OUTPUT)/,*.o *.skel.h no_alu32 bpf_gcc bpf_testmod.ko)
+
+.PHONY: docs docs-clean
diff --git a/tools/testing/selftests/bpf/Makefile.docs b/tools/testing/selftests/bpf/Makefile.docs
new file mode 100644
index 000000000000..546c4a763b46
--- /dev/null
+++ b/tools/testing/selftests/bpf/Makefile.docs
@@ -0,0 +1,62 @@
+# SPDX-License-Identifier: GPL-2.0-only
+
+include ../../../scripts/Makefile.include
+include ../../../scripts/utilities.mak
+
+INSTALL ?= install
+RM ?= rm -f
+RMDIR ?= rmdir --ignore-fail-on-non-empty
+
+ifeq ($(V),1)
+  Q =
+else
+  Q = @
+endif
+
+prefix ?= /usr/local
+mandir ?= $(prefix)/man
+man7dir = $(mandir)/man7
+
+HELPERS_RST = bpf-helpers.rst
+MAN7_RST = $(HELPERS_RST)
+
+_DOC_MAN7 = $(patsubst %.rst,%.7,$(MAN7_RST))
+DOC_MAN7 = $(addprefix $(OUTPUT),$(_DOC_MAN7))
+
+DOCTARGETS := helpers
+
+docs: $(DOCTARGETS)
+helpers: man7
+man7: $(DOC_MAN7)
+
+RST2MAN_DEP := $(shell command -v rst2man 2>/dev/null)
+
+# Configure make rules for the man page bpf-$1.$2.
+# $1 - target for scripts/bpf_doc.py
+# $2 - man page section to generate the troff file
+define DOCS_RULES =
+$(OUTPUT)bpf-$1.rst: ../../../../include/uapi/linux/bpf.h
+	$$(QUIET_GEN)../../../../scripts/bpf_doc.py $1 \
+		--filename $$< > $$@
+
+$(OUTPUT)%.7: $(OUTPUT)%.rst
+ifndef RST2MAN_DEP
+	$(error "rst2man not found, but required to generate man pages")
+endif
+	$(QUIET_GEN)rst2man $< > $@
+
+docs-clean:
+	$(call QUIET_CLEAN, eBPF_helpers-manpage)
+	$(Q)$(RM) $(DOC_MAN7) $(OUTPUT)$(HELPERS_RST)
+
+docs-install: helpers
+	$(call QUIET_INSTALL, eBPF_helpers-manpage)
+	$(Q)$(INSTALL) -d -m 755 $(DESTDIR)$(man7dir)
+	$(Q)$(INSTALL) -m 644 $(DOC_MAN7) $(DESTDIR)$(man7dir)
+
+docs-uninstall:
+	$(call QUIET_UNINST, eBPF_helpers-manpage)
+	$(Q)$(RM) $(addprefix $(DESTDIR)$(man7dir)/,$(_DOC_MAN7))
+	$(Q)$(RMDIR) $(DESTDIR)$(man7dir)
+
+.PHONY: docs docs-clean docs-install docs-uninstall
diff --git a/tools/testing/selftests/bpf/test_bpftool_build.sh b/tools/testing/selftests/bpf/test_bpftool_build.sh
index 2db3c60e1e61..ac349a5cea7e 100755
--- a/tools/testing/selftests/bpf/test_bpftool_build.sh
+++ b/tools/testing/selftests/bpf/test_bpftool_build.sh
@@ -85,23 +85,6 @@ make_with_tmpdir() {
 	echo
 }
 
-make_doc_and_clean() {
-	echo -e "\$PWD:    $PWD"
-	echo -e "command: make -s $* doc >/dev/null"
-	RST2MAN_OPTS="--exit-status=1" make $J -s $* doc
-	if [ $? -ne 0 ] ; then
-		ERROR=1
-		printf "FAILURE: Errors or warnings when building documentation\n"
-	fi
-	(
-		if [ $# -ge 1 ] ; then
-			cd ${@: -1}
-		fi
-		make -s doc-clean
-	)
-	echo
-}
-
 echo "Trying to build bpftool"
 echo -e "... through kbuild\n"
 
@@ -162,7 +145,3 @@ make_and_clean
 make_with_tmpdir OUTPUT
 
 make_with_tmpdir O
-
-echo -e "Checking documentation build\n"
-# From tools/bpf/bpftool
-make_doc_and_clean
diff --git a/tools/testing/selftests/bpf/test_doc_build.sh b/tools/testing/selftests/bpf/test_doc_build.sh
new file mode 100755
index 000000000000..7eb940a7b2eb
--- /dev/null
+++ b/tools/testing/selftests/bpf/test_doc_build.sh
@@ -0,0 +1,13 @@
+#!/bin/bash
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+
+# Assume script is located under tools/testing/selftests/bpf/. We want to start
+# build attempts from the top of kernel repository.
+SCRIPT_REL_PATH=$(realpath --relative-to=$PWD $0)
+SCRIPT_REL_DIR=$(dirname $SCRIPT_REL_PATH)
+KDIR_ROOT_DIR=$(realpath $PWD/$SCRIPT_REL_DIR/../../../../)
+cd $KDIR_ROOT_DIR
+
+for tgt in docs docs-clean; do
+	make -s -C $PWD/$SCRIPT_REL_DIR $tgt;
+done