tc-testing: fix build of eBPF programs

[ Upstream commit cf5eafbf ]

rely on uAPI headers in the current kernel tree, rather than requiring the
correct version installed on the test system. While at it, group all
sections in a single binary and test the 'section' parameter.
Reported-by: Lucas Bates <lucasb@mojatatu.com>
Signed-off-by: Davide Caratti <dcaratti@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>

tools/testing/selftests/tc-testing/bpf/Makefile

+# SPDX-License-Identifier: GPL-2.0
+
+APIDIR := ../../../../include/uapi
+TEST_GEN_FILES = action.o
+
+top_srcdir = ../../../../..
+include ../../lib.mk
+
+CLANG ?= clang
+LLC   ?= llc
+PROBE := $(shell $(LLC) -march=bpf -mcpu=probe -filetype=null /dev/null 2>&1)
+
+ifeq ($(PROBE),)
+  CPU ?= probe
+else
+  CPU ?= generic
+endif
+
+CLANG_SYS_INCLUDES := $(shell $(CLANG) -v -E - </dev/null 2>&1 \
+	| sed -n '/<...> search starts here:/,/End of search list./{ s| \(/.*\)|-idirafter \1|p }')
+
+CLANG_FLAGS = -I. -I$(APIDIR) \
+	      $(CLANG_SYS_INCLUDES) \
+	      -Wno-compare-distinct-pointer-types
+
+$(OUTPUT)/%.o: %.c
+	$(CLANG) $(CLANG_FLAGS) \
+		 -O2 -target bpf -emit-llvm -c $< -o - |      \
+	$(LLC) -march=bpf -mcpu=$(CPU) $(LLC_FLAGS) -filetype=obj -o $@

tools/testing/selftests/tc-testing/bpf/action.c

+/* SPDX-License-Identifier: GPL-2.0
+ * Copyright (c) 2018 Davide Caratti, Red Hat inc.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of version 2 of the GNU General Public
+ * License as published by the Free Software Foundation.
+ */
+
+#include <linux/bpf.h>
+#include <linux/pkt_cls.h>
+
+__attribute__((section("action-ok"),used)) int action_ok(struct __sk_buff *s)
+{
+	return TC_ACT_OK;
+}
+
+__attribute__((section("action-ko"),used)) int action_ko(struct __sk_buff *s)
+{
+	s->data = 0x0;
+	return TC_ACT_OK;
+}
+
+char _license[] __attribute__((section("license"),used)) = "GPL";

tools/testing/selftests/tc-testing/tc-tests/actions/bpf.json

@@ -55,7 +55,7 @@
             "bpf"
         ],
         "setup": [
-            "printf '#include <linux/bpf.h>\nchar l[] __attribute__((section(\"license\"),used))=\"GPL\"; __attribute__((section(\"action\"),used)) int m(struct __sk_buff *s) { return 2; }' | clang -O2 -x c -c - -target bpf -o _b.o",
+            "make -C bpf",
             [
                 "$TC action flush action bpf",
                 0,
@@ -63,14 +63,14 @@
                 255
             ]
         ],
-        "cmdUnderTest": "$TC action add action bpf object-file _b.o index 667",
+        "cmdUnderTest": "$TC action add action bpf object-file $EBPFDIR/action.o section action-ok index 667",
         "expExitCode": "0",
         "verifyCmd": "$TC action get action bpf index 667",
-        "matchPattern": "action order [0-9]*: bpf _b.o:\\[action\\] id [0-9]* tag 3b185187f1855c4c( jited)? default-action pipe.*index 667 ref",
+        "matchPattern": "action order [0-9]*: bpf action.o:\\[action-ok\\] id [0-9]* tag [0-9a-f]{16}( jited)? default-action pipe.*index 667 ref",
         "matchCount": "1",
         "teardown": [
             "$TC action flush action bpf",
-            "rm -f _b.o"
+            "make -C bpf clean"
         ]
     },
     {
@@ -81,7 +81,7 @@
             "bpf"
         ],
         "setup": [
-            "printf '#include <linux/bpf.h>\nchar l[] __attribute__((section(\"license\"),used))=\"GPL\"; __attribute__((section(\"action\"),used)) int m(struct __sk_buff *s) { s->data = 0x0; return 2; }' | clang -O2 -x c -c - -target bpf -o _c.o",
+            "make -C bpf",
             [
                 "$TC action flush action bpf",
                 0,
@@ -89,10 +89,10 @@
                 255
             ]
         ],
-        "cmdUnderTest": "$TC action add action bpf object-file _c.o index 667",
+        "cmdUnderTest": "$TC action add action bpf object-file $EBPFDIR/action.o section action-ko index 667",
         "expExitCode": "255",
         "verifyCmd": "$TC action get action bpf index 667",
-        "matchPattern": "action order [0-9]*: bpf _c.o:\\[action\\] id [0-9].*index 667 ref",
+        "matchPattern": "action order [0-9]*: bpf action.o:\\[action-ko\\] id [0-9].*index 667 ref",
         "matchCount": "0",
         "teardown": [
             [
@@ -101,7 +101,7 @@
                 1,
                 255
             ],
-            "rm -f _c.o"
+            "make -C bpf clean"
         ]
     },
     {

tools/testing/selftests/tc-testing/tdc_config.py

@@ -16,7 +16,9 @@ NAMES = {
           'DEV2': '',
           'BATCH_FILE': './batch.txt',
           # Name of the namespace to use
-          'NS': 'tcut'
+          'NS': 'tcut',
+          # Directory containing eBPF test programs
+          'EBPFDIR': './bpf'
         }