selftests/bpf: Skip building arena tests if unsupported

BPF selftests always try building arena tests, but since kernel arena
support is not built-in on unsupported archs, this leads to failures trying
to build e.g. test_progs on 32-bit, and complicates 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 as needed (e.g. prog_tests/verifier.c).

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

Author: guidosarducci

tools/testing/selftests/bpf/Makefile

@@ -540,13 +540,16 @@ 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,		\
 				 $$(filter %.c,$(TRUNNER_EXTRA_SOURCES)))
 TRUNNER_EXTRA_HDRS := $$(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,	\
 				 $$(filter-out $(SKEL_BLACKLIST) $(LINKED_BPF_SRCS),\
@@ -649,7 +652,9 @@ $(TRUNNER_TESTS_HDR): $(TRUNNER_TESTS_DIR)/*.c
 	$$(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
 
@@ -724,6 +729,8 @@ $(VERIFICATION_CERT) $(PRIVATE_KEY): $(VERIFY_SIG_SETUP)
 $(VERIFY_SIG_HDR): $(VERIFICATION_CERT)
 	$(Q)xxd -i -n test_progs_verification_cert $< > $@
 
+ENABLE_ARENA_TESTS := $(filter $(SRCARCH),x86 riscv s390 arm64)
+
 # Define test_progs test runner.
 TRUNNER_TESTS_DIR := prog_tests
 TRUNNER_BPF_PROGS_DIR := progs
@@ -756,6 +763,10 @@ 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))
@@ -897,6 +908,9 @@ $(OUTPUT)/uprobe_autoattach.test.o					\
 $(OUTPUT)/usdt.test.o							\
 $(OUTPUT)/uprobe_multi:	CFLAGS += $(if $(filter arm, $(ARCH)),-marm)
 
+# Disable arena verifier tests when unsupported
+$(OUTPUT)/verifier.test.o: CFLAGS += $(if $(ENABLE_ARENA_TESTS),-DENABLE_ARENA_TESTS)
+
 EXTRA_CLEAN := $(SCRATCH_DIR) $(HOST_SCRATCH_DIR)			\
 	prog_tests/tests.h map_tests/tests.h verifier/tests.h		\
 	feature bpftool $(TEST_KMOD_TARGETS)				\

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

@@ -4,8 +4,12 @@
 
 #include "cap_helpers.h"
 #include "verifier_and.skel.h"
+
+#ifdef ENABLE_ARENA_TESTS
 #include "verifier_arena.skel.h"
 #include "verifier_arena_large.skel.h"
+#endif
+
 #include "verifier_array_access.skel.h"
 #include "verifier_basic_stack.skel.h"
 #include "verifier_bitfield_write.skel.h"
@@ -143,8 +147,10 @@ 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); }
+#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); }