selftests/bpf: Skip building arena tests if unsupported

BPF selftests always try building with arena tests, but since kernel arena
support is not built-in on unsupported archs, this leads to failures trying
to build or run (e.g. seen with test_progs on 32-bit), and can complicate
overall testing.

Past arena test code has been mainly added as separate source files, making
it simpler to selectively build the tests. Update Makefile to filter out
arena test sources from build rules and the tests.h header, and pass macro
ENABLE_ARENA_TESTS via CFLAGS (e.g. for prog_tests/verifier.c).

Signed-off-by: Tony Ambardar <[email protected]>

Author: guidosarducci

tools/testing/selftests/bpf/Makefile

@@ -74,6 +74,10 @@ ifneq ($(shell $(CLANG) --target=bpf -mcpu=help 2>&1 | grep 'v4'),)
 CLANG_CPUV4 := 1
 endif
 
+# Enable arena verifier tests only if supported
+ENABLE_ARENA_TESTS := $(filter $(SRCARCH),x86 riscv s390 arm64)
+CFLAGS += $(if $(ENABLE_ARENA_TESTS),-DENABLE_ARENA_TESTS)
+
 # Order correspond to 'make run_tests' order
 TEST_GEN_PROGS = test_verifier test_tag test_maps test_lru_map test_progs \
 	test_sockmap \
@@ -545,15 +549,18 @@ define DEFINE_TEST_RUNNER
 LSKEL_SIGN := -S -k $(PRIVATE_KEY) -i $(VERIFICATION_CERT)
 TRUNNER_OUTPUT := $(OUTPUT)$(if $2,/)$2
 TRUNNER_BINARY := $1$(if $2,-)$2
+TRUNNER_TEST_SRCS := $$(filter-out $(TRUNNER_ARENA_FILTER), $$(notdir	\
+				   $$(wildcard $(TRUNNER_TESTS_DIR)/*.c)))
 TRUNNER_TEST_OBJS := $$(patsubst %.c,$$(TRUNNER_OUTPUT)/%.test.o,	\
-				 $$(notdir $$(wildcard $(TRUNNER_TESTS_DIR)/*.c)))
+				 $$(TRUNNER_TEST_SRCS))
 TRUNNER_EXTRA_OBJS := $$(patsubst %.c,$$(TRUNNER_OUTPUT)/%.o,		\
 				 $$(filter %.c,$(TRUNNER_EXTRA_SOURCES)))
 TRUNNER_LIB_OBJS := $$(patsubst %.c,$$(TRUNNER_OUTPUT)/%.o,		\
 				 $$(filter %.c,$(TRUNNER_LIB_SOURCES)))
 TRUNNER_EXTRA_HDRS := $$(filter %.h,$(TRUNNER_EXTRA_SOURCES))
 TRUNNER_TESTS_HDR := $(TRUNNER_TESTS_DIR)/tests.h
-TRUNNER_BPF_SRCS := $$(notdir $$(wildcard $(TRUNNER_BPF_PROGS_DIR)/*.c))
+TRUNNER_BPF_SRCS := $$(filter-out $(TRUNNER_ARENA_FILTER), $$(notdir	\
+				  $$(wildcard $(TRUNNER_BPF_PROGS_DIR)/*.c)))
 TRUNNER_BPF_OBJS := $$(patsubst %.c,$$(TRUNNER_OUTPUT)/%.bpf.o, $$(TRUNNER_BPF_SRCS))
 TRUNNER_BPF_SKELS := $$(patsubst %.c,$$(TRUNNER_OUTPUT)/%.skel.h,	\
 				 $$(filter-out $(SKEL_BLACKLIST) $(LINKED_BPF_SRCS),\
@@ -656,7 +663,9 @@ $(TRUNNER_TESTS_HDR): $(TRUNNER_TESTS_DIR)/*.c
 	$$(call msg,TEST-HDR,$(TRUNNER_BINARY),$$@)
 	$$(shell (echo '/* Generated header, do not edit */';					\
 		  sed -n -E 's/^void (serial_)?test_([a-zA-Z0-9_]+)\((void)?\).*/DEFINE_TEST(\2)/p'	\
-			$(TRUNNER_TESTS_DIR)/*.c | sort ;	\
+			$(TRUNNER_TESTS_DIR)/*.c			\
+			$$(if $(ENABLE_ARENA_TESTS),,| grep -v 'arena')	\
+			| sort ;	\
 		 ) > $$@)
 endif
 
@@ -769,6 +778,10 @@ TRUNNER_EXTRA_FILES := $(OUTPUT)/urandom_read				\
 		       $(VERIFY_SIG_SETUP)				\
 		       $(wildcard progs/btf_dump_test_case_*.c)		\
 		       $(wildcard progs/*.bpf.o)
+ifeq ($(ENABLE_ARENA_TESTS),)
+TRUNNER_ARENA_FILTER := $(notdir $(wildcard prog_tests/*arena*.c)	\
+				 $(wildcard progs/*arena*.c))
+endif
 TRUNNER_BPF_BUILD_RULE := CLANG_BPF_BUILD_RULE
 TRUNNER_BPF_CFLAGS := $(BPF_CFLAGS) $(CLANG_CFLAGS) -DENABLE_ATOMICS_TESTS
 $(eval $(call DEFINE_TEST_RUNNER,test_progs))

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

@@ -4,9 +4,13 @@
 
 #include "cap_helpers.h"
 #include "verifier_and.skel.h"
+
+#ifdef ENABLE_ARENA_TESTS
 #include "verifier_arena.skel.h"
 #include "verifier_arena_large.skel.h"
 #include "verifier_arena_ldsx.skel.h"
+#endif
+
 #include "verifier_array_access.skel.h"
 #include "verifier_async_cb_context.skel.h"
 #include "verifier_basic_stack.skel.h"
@@ -146,9 +150,11 @@ static void run_tests_aux(const char *skel_name,
 #define RUN(skel) run_tests_aux(#skel, skel##__elf_bytes, NULL)
 
 void test_verifier_and(void)                  { RUN(verifier_and); }
+#ifdef ENABLE_ARENA_TESTS
 void test_verifier_arena(void)                { RUN(verifier_arena); }
 void test_verifier_arena_large(void)          { RUN(verifier_arena_large); }
 void test_verifier_arena_ldsx(void)           { RUN(verifier_arena_ldsx); }
+#endif
 void test_verifier_basic_stack(void)          { RUN(verifier_basic_stack); }
 void test_verifier_bitfield_write(void)       { RUN(verifier_bitfield_write); }
 void test_verifier_bounds(void)               { RUN(verifier_bounds); }