Merge branch 'cleanup-selftests-bpf-makefile'

Andrii Nakryiko says:

====================
This patch set extensively revamps selftests/bpf's Makefile to generalize test
runner concept and apply it uniformly to test_maps and test_progs test
runners, along with test_progs' few build "flavors", exercising various ways
to build BPF programs.

As we do that, we fix dependencies between various phases of test runners, and
simplify some one-off rules and dependencies currently present in Makefile.
test_progs' flavors are now built into root $(OUTPUT) directory and can be run
without any extra steps right from there. E.g., test_progs-alu32 is built and
is supposed to be run from $(OUTPUT). It will cd into alu32/ subdirectory to
load correct set of BPF object files (which are different from the ones built
for test_progs).

Outline:
- patch #1 teaches test_progs about flavor sub-directories;
- patch #2 fixes one of CO-RE tests to not depend strictly on process name;
- patch #3 changes test_maps's usage of map_tests/tests.h to be the same as
  test_progs' one;
- patch #4 adds convenient short `make test_progs`-like targets to build only
  individual tests, if necessary;
- patch #5 is a main patch in the series; it uses a bunch of make magic
  (mainly $(call) and $(eval)) to define test runner "skeleton" and apply it
  to 4 different test runners, lots more details in corresponding commit
  description;
- patch #6 does a bit of post-clean up for test_queue_map and test_stack_map
  BPF programs;
- patch #7 cleans up test_libbpf.sh/test_libbpf_open superseded by test_progs.

v3->v4:
- remove accidentally checked in binaries;

v2->v3:
- drop test_xdp.o mixed compilation mode, remove test_libbpf.sh (Alexei);

v1->v2:
- drop test_progs-native causing compilation failures due to
  __builtin_preserve_field_access, add back test_xdp.o override, which will
  now emit rule re-definition warning.
====================
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

tools/testing/selftests/bpf/.gitignore

@@ -7,11 +7,10 @@ FEATURE-DUMP.libbpf
 fixdep
 test_align
 test_dev_cgroup
-test_progs
+/test_progs*
 test_tcpbpf_user
 test_verifier_log
 feature
-test_libbpf_open
 test_sock
 test_sock_addr
 test_sock_fields
@@ -33,9 +32,10 @@ test_tcpnotify_user
 test_libbpf
 test_tcp_check_syncookie_user
 test_sysctl
-alu32
 libbpf.pc
 libbpf.so.*
 test_hashmap
 test_btf_dump
 xdping
+/alu32
+/bpf_gcc

tools/testing/selftests/bpf/prog_tests/core_reloc.c

@@ -211,8 +211,8 @@ static struct core_reloc_test_case test_cases[] = {
 		.input_len = 0,
 		.output = STRUCT_TO_CHAR_PTR(core_reloc_kernel_output) {
 			.valid = { 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, },
-			.comm = "test_progs\0\0\0\0\0",
-			.comm_len = 11,
+			.comm = "test_progs",
+			.comm_len = sizeof("test_progs"),
 		},
 		.output_len = sizeof(struct core_reloc_kernel_output),
 	},

tools/testing/selftests/bpf/progs/core_reloc_types.h

@@ -6,7 +6,7 @@
 
 struct core_reloc_kernel_output {
 	int valid[10];
-	char comm[16];
+	char comm[sizeof("test_progs")];
 	int comm_len;
 };
 

tools/testing/selftests/bpf/progs/test_core_reloc_kernel.c

@@ -15,7 +15,8 @@ static volatile struct data {
 
 struct core_reloc_kernel_output {
 	int valid[10];
-	char comm[16];
+	/* we have test_progs[-flavor], so cut flavor part */
+	char comm[sizeof("test_progs")];
 	int comm_len;
 };
 

tools/testing/selftests/bpf/test_libbpf.sh

-#!/bin/sh
-# SPDX-License-Identifier: GPL-2.0
-
-export TESTNAME=test_libbpf
-
-# Determine selftest success via shell exit code
-exit_handler()
-{
-	if [ $? -eq 0 ]; then
-		echo "selftests: $TESTNAME [PASS]";
-	else
-		echo "$TESTNAME: failed at file $LAST_LOADED" 1>&2
-		echo "selftests: $TESTNAME [FAILED]";
-	fi
-}
-
-libbpf_open_file()
-{
-	LAST_LOADED=$1
-	if [ -n "$VERBOSE" ]; then
-	    ./test_libbpf_open $1
-	else
-	    ./test_libbpf_open --quiet $1
-	fi
-}
-
-# Exit script immediately (well catched by trap handler) if any
-# program/thing exits with a non-zero status.
-set -e
-
-# (Use 'trap -l' to list meaning of numbers)
-trap exit_handler 0 2 3 6 9
-
-libbpf_open_file test_l4lb.o
-
-# Load a program with BPF-to-BPF calls
-libbpf_open_file test_l4lb_noinline.o
-
-# Load a program compiled without the "-target bpf" flag
-libbpf_open_file test_xdp.o
-
-# Success
-exit 0

tools/testing/selftests/bpf/test_libbpf_open.c

-/* SPDX-License-Identifier: GPL-2.0
- * Copyright (c) 2018 Jesper Dangaard Brouer, Red Hat Inc.
- */
-static const char *__doc__ =
-	"Libbpf test program for loading BPF ELF object files";
-
-#include <stdlib.h>
-#include <stdio.h>
-#include <string.h>
-#include <stdarg.h>
-#include <bpf/libbpf.h>
-#include <getopt.h>
-
-#include "bpf_rlimit.h"
-
-static const struct option long_options[] = {
-	{"help",	no_argument,		NULL, 'h' },
-	{"debug",	no_argument,		NULL, 'D' },
-	{"quiet",	no_argument,		NULL, 'q' },
-	{0, 0, NULL,  0 }
-};
-
-static void usage(char *argv[])
-{
-	int i;
-
-	printf("\nDOCUMENTATION:\n%s\n\n", __doc__);
-	printf(" Usage: %s (options-see-below) BPF_FILE\n", argv[0]);
-	printf(" Listing options:\n");
-	for (i = 0; long_options[i].name != 0; i++) {
-		printf(" --%-12s", long_options[i].name);
-		printf(" short-option: -%c",
-		       long_options[i].val);
-		printf("\n");
-	}
-	printf("\n");
-}
-
-static bool debug = 0;
-static int libbpf_debug_print(enum libbpf_print_level level,
-			      const char *fmt, va_list args)
-{
-	if (level == LIBBPF_DEBUG && !debug)
-		return 0;
-
-	fprintf(stderr, "[%d] ", level);
-	return vfprintf(stderr, fmt, args);
-}
-
-#define EXIT_FAIL_LIBBPF EXIT_FAILURE
-#define EXIT_FAIL_OPTION 2
-
-int test_walk_progs(struct bpf_object *obj, bool verbose)
-{
-	struct bpf_program *prog;
-	int cnt = 0;
-
-	bpf_object__for_each_program(prog, obj) {
-		cnt++;
-		if (verbose)
-			printf("Prog (count:%d) section_name: %s\n", cnt,
-			       bpf_program__title(prog, false));
-	}
-	return 0;
-}
-
-int test_walk_maps(struct bpf_object *obj, bool verbose)
-{
-	struct bpf_map *map;
-	int cnt = 0;
-
-	bpf_object__for_each_map(map, obj) {
-		cnt++;
-		if (verbose)
-			printf("Map (count:%d) name: %s\n", cnt,
-			       bpf_map__name(map));
-	}
-	return 0;
-}
-
-int test_open_file(char *filename, bool verbose)
-{
-	struct bpf_object *bpfobj = NULL;
-	long err;
-
-	if (verbose)
-		printf("Open BPF ELF-file with libbpf: %s\n", filename);
-
-	/* Load BPF ELF object file and check for errors */
-	bpfobj = bpf_object__open(filename);
-	err = libbpf_get_error(bpfobj);
-	if (err) {
-		char err_buf[128];
-		libbpf_strerror(err, err_buf, sizeof(err_buf));
-		if (verbose)
-			printf("Unable to load eBPF objects in file '%s': %s\n",
-			       filename, err_buf);
-		return EXIT_FAIL_LIBBPF;
-	}
-	test_walk_progs(bpfobj, verbose);
-	test_walk_maps(bpfobj, verbose);
-
-	if (verbose)
-		printf("Close BPF ELF-file with libbpf: %s\n",
-		       bpf_object__name(bpfobj));
-	bpf_object__close(bpfobj);
-
-	return 0;
-}
-
-int main(int argc, char **argv)
-{
-	char filename[1024] = { 0 };
-	bool verbose = 1;
-	int longindex = 0;
-	int opt;
-
-	libbpf_set_print(libbpf_debug_print);
-
-	/* Parse commands line args */
-	while ((opt = getopt_long(argc, argv, "hDq",
-				  long_options, &longindex)) != -1) {
-		switch (opt) {
-		case 'D':
-			debug = 1;
-			break;
-		case 'q': /* Use in scripting mode */
-			verbose = 0;
-			break;
-		case 'h':
-		default:
-			usage(argv);
-			return EXIT_FAIL_OPTION;
-		}
-	}
-	if (optind >= argc) {
-		usage(argv);
-		printf("ERROR: Expected BPF_FILE argument after options\n");
-		return EXIT_FAIL_OPTION;
-	}
-	snprintf(filename, sizeof(filename), "%s", argv[optind]);
-
-	return test_open_file(filename, verbose);
-}

tools/testing/selftests/bpf/test_maps.c

@@ -1717,9 +1717,9 @@ static void run_all_tests(void)
 	test_map_in_map();
 }
 
-#define DECLARE
+#define DEFINE_TEST(name) extern void test_##name(void);
 #include <map_tests/tests.h>
-#undef DECLARE
+#undef DEFINE_TEST
 
 int main(void)
 {
@@ -1731,9 +1731,9 @@ int main(void)
 	map_flags = BPF_F_NO_PREALLOC;
 	run_all_tests();
 
-#define CALL
+#define DEFINE_TEST(name) test_##name();
 #include <map_tests/tests.h>
-#undef CALL
+#undef DEFINE_TEST
 
 	printf("test_maps: OK, %d SKIPPED\n", skips);
 	return 0;

tools/testing/selftests/bpf/test_progs.c

@@ -306,7 +306,7 @@ void *spin_lock_thread(void *arg)
 }
 
 /* extern declarations for test funcs */
-#define DEFINE_TEST(name) extern void test_##name();
+#define DEFINE_TEST(name) extern void test_##name(void);
 #include <prog_tests/tests.h>
 #undef DEFINE_TEST
 
@@ -518,6 +518,33 @@ static void stdio_restore(void)
 #endif
 }
 
+/*
+ * Determine if test_progs is running as a "flavored" test runner and switch
+ * into corresponding sub-directory to load correct BPF objects.
+ *
+ * This is done by looking at executable name. If it contains "-flavor"
+ * suffix, then we are running as a flavored test runner.
+ */
+int cd_flavor_subdir(const char *exec_name)
+{
+	/* General form of argv[0] passed here is:
+	 * some/path/to/test_progs[-flavor], where -flavor part is optional.
+	 * First cut out "test_progs[-flavor]" part, then extract "flavor"
+	 * part, if it's there.
+	 */
+	const char *flavor = strrchr(exec_name, '/');
+
+	if (!flavor)
+		return 0;
+	flavor++;
+	flavor = strrchr(flavor, '-');
+	if (!flavor)
+		return 0;
+	flavor++;
+	printf("Switching to flavor '%s' subdirectory...\n", flavor);
+	return chdir(flavor);
+}
+
 int main(int argc, char **argv)
 {
 	static const struct argp argp = {
@@ -531,6 +558,10 @@ int main(int argc, char **argv)
 	if (err)
 		return err;
 
+	err = cd_flavor_subdir(argv[0]);
+	if (err)
+		return err;
+
 	libbpf_set_print(libbpf_print_fn);
 
 	srand(time(NULL));