From 4ce150b6a412f14074400eac5fc39d1a71c4ef0a Mon Sep 17 00:00:00 2001 From: Ilya Leoshkevich Date: Thu, 12 Sep 2019 18:05:43 +0200 Subject: [PATCH] selftests/bpf: add bpf-gcc support Now that binutils and gcc support for BPF is upstream, make use of it in BPF selftests using alu32-like approach. Share as much as possible of CFLAGS calculation with clang. Fixes only obvious issues, leaving more complex ones for later: - Use gcc-provided bpf-helpers.h instead of manually defining the helpers, change bpf_helpers.h include guard to avoid conflict. - Include for __always_inline. - Add $(OUTPUT)/../usr/include to include path in order to use local kernel headers instead of system kernel headers when building with O=. In order to activate the bpf-gcc support, one needs to configure binutils and gcc with --target=bpf and make them available in $PATH. In particular, gcc must be installed as `bpf-gcc`, which is the default. Right now with binutils 25a2915e8dba and gcc r275589 only a handful of tests work: # ./test_progs_bpf_gcc # Summary: 7/39 PASSED, 1 SKIPPED, 98 FAILED The reason for those failures are as follows: - Build errors: - `error: too many function arguments for eBPF` for __always_inline functions read_str_var and read_map_var - must be inlining issue, and for process_l3_headers_v6, which relies on optimizing away function arguments. - `error: indirect call in function, which are not supported by eBPF` where there are no obvious indirect calls in the source calls, e.g. in __encap_ipip_none. - `error: field 'lock' has incomplete type` for fields of `struct bpf_spin_lock` type - bpf_spin_lock is re#defined by bpf-helpers.h, so its usage is sensitive to order of #includes. - `error: eBPF stack limit exceeded` in sysctl_tcp_mem. - Load errors: - Missing object files due to above build errors. - `libbpf: failed to create map (name: 'test_ver.bss')`. - `libbpf: object file doesn't contain bpf program`. - `libbpf: Program '.text' contains unrecognized relo data pointing to section 0`. - `libbpf: BTF is required, but is missing or corrupted` - no BTF support in gcc yet. Signed-off-by: Ilya Leoshkevich Cc: Jose E. Marchesi Signed-off-by: Daniel Borkmann --- tools/testing/selftests/bpf/Makefile | 65 +++++++++++++++++++------ tools/testing/selftests/bpf/bpf_helpers.h | 24 ++++++--- tools/testing/selftests/bpf/progs/test_tc_edt.c | 1 + 3 files changed, 67 insertions(+), 23 deletions(-) diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile index 7f3196a..6889c19 100644 --- a/tools/testing/selftests/bpf/Makefile +++ b/tools/testing/selftests/bpf/Makefile @@ -17,6 +17,7 @@ LLC ?= llc LLVM_OBJCOPY ?= llvm-objcopy LLVM_READELF ?= llvm-readelf BTF_PAHOLE ?= pahole +BPF_GCC ?= $(shell command -v bpf-gcc;) CFLAGS += -g -Wall -O2 -I$(APIDIR) -I$(LIBDIR) -I$(BPFDIR) -I$(GENDIR) $(GENFLAGS) -I../../../include \ -Dbpf_prog_load=bpf_prog_test_load \ -Dbpf_load_program=bpf_test_load_program @@ -46,6 +47,10 @@ ifneq ($(SUBREG_CODEGEN),) TEST_GEN_FILES += $(patsubst %.o,alu32/%.o, $(BPF_OBJ_FILES)) endif +ifneq ($(BPF_GCC),) +TEST_GEN_FILES += $(patsubst %.o,bpf_gcc/%.o, $(BPF_OBJ_FILES)) +endif + # Order correspond to 'make run_tests' order TEST_PROGS := test_kmod.sh \ test_libbpf.sh \ @@ -137,16 +142,19 @@ endif # # Use '-idirafter': Don't interfere with include mechanics except where the # build would have failed anyways. -CLANG_SYS_INCLUDES := $(shell $(CLANG) -v -E - &1 \ +define get_sys_includes +$(shell $(1) -v -E - &1 \ | sed -n '/<...> search starts here:/,/End of search list./{ s| \(/.*\)|-idirafter \1|p }') +endef +CLANG_SYS_INCLUDES = $(call get_sys_includes,$(CLANG)) +BPF_CFLAGS = -I. -I./include/uapi -I../../../include/uapi \ + -I$(OUTPUT)/../usr/include -D__TARGET_ARCH_$(SRCARCH) -CLANG_FLAGS = -I. -I./include/uapi -I../../../include/uapi \ - $(CLANG_SYS_INCLUDES) \ - -Wno-compare-distinct-pointer-types \ - -D__TARGET_ARCH_$(SRCARCH) +CLANG_CFLAGS = $(CLANG_SYS_INCLUDES) \ + -Wno-compare-distinct-pointer-types -$(OUTPUT)/test_l4lb_noinline.o: CLANG_FLAGS += -fno-inline -$(OUTPUT)/test_xdp_noinline.o: CLANG_FLAGS += -fno-inline +$(OUTPUT)/test_l4lb_noinline.o: BPF_CFLAGS += -fno-inline +$(OUTPUT)/test_xdp_noinline.o: BPF_CFLAGS += -fno-inline $(OUTPUT)/test_queue_map.o: test_queue_stack_map.h $(OUTPUT)/test_stack_map.o: test_queue_stack_map.h @@ -163,12 +171,12 @@ BTF_LLVM_PROBE := $(shell echo "int main() { return 0; }" | \ /bin/rm -f ./llvm_btf_verify.o) ifneq ($(BTF_LLVM_PROBE),) - CLANG_FLAGS += -g + BPF_CFLAGS += -g else ifneq ($(BTF_LLC_PROBE),) ifneq ($(BTF_PAHOLE_PROBE),) ifneq ($(BTF_OBJCOPY_PROBE),) - CLANG_FLAGS += -g + BPF_CFLAGS += -g LLC_FLAGS += -mattr=dwarfris DWARF2BTF = y endif @@ -202,8 +210,8 @@ $(ALU32_BUILD_DIR)/test_progs_32: prog_tests/*.c $(ALU32_BUILD_DIR)/%.o: progs/%.c $(ALU32_BUILD_DIR)/test_progs_32 \ | $(ALU32_BUILD_DIR) - ($(CLANG) $(CLANG_FLAGS) -O2 -target bpf -emit-llvm -c $< -o - || \ - echo "clang failed") | \ + ($(CLANG) $(BPF_CFLAGS) $(CLANG_CFLAGS) -O2 -target bpf -emit-llvm \ + -c $< -o - || echo "clang failed") | \ $(LLC) -march=bpf -mattr=+alu32 -mcpu=$(CPU) $(LLC_FLAGS) \ -filetype=obj -o $@ ifeq ($(DWARF2BTF),y) @@ -211,10 +219,37 @@ ifeq ($(DWARF2BTF),y) endif endif +ifneq ($(BPF_GCC),) +GCC_SYS_INCLUDES = $(call get_sys_includes,gcc) +IS_LITTLE_ENDIAN = $(shell $(CC) -dM -E - $(VERIFIER_TESTS_H)) -EXTRA_CLEAN := $(TEST_CUSTOM_PROGS) $(ALU32_BUILD_DIR) \ +EXTRA_CLEAN := $(TEST_CUSTOM_PROGS) $(ALU32_BUILD_DIR) $(BPF_GCC_BUILD_DIR) \ $(VERIFIER_TESTS_H) $(PROG_TESTS_H) $(MAP_TESTS_H) \ feature diff --git a/tools/testing/selftests/bpf/bpf_helpers.h b/tools/testing/selftests/bpf/bpf_helpers.h index 6c4930b..54a5069 100644 --- a/tools/testing/selftests/bpf/bpf_helpers.h +++ b/tools/testing/selftests/bpf/bpf_helpers.h @@ -1,12 +1,6 @@ /* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */ -#ifndef __BPF_HELPERS_H -#define __BPF_HELPERS_H - -/* helper macro to place programs, maps, license in - * different sections in elf_bpf file. Section names - * are interpreted by elf_bpf loader - */ -#define SEC(NAME) __attribute__((section(NAME), used)) +#ifndef __BPF_HELPERS__ +#define __BPF_HELPERS__ #define __uint(name, val) int (*name)[val] #define __type(name, val) val *name @@ -19,6 +13,14 @@ ##__VA_ARGS__); \ }) +#ifdef __clang__ + +/* helper macro to place programs, maps, license in + * different sections in elf_bpf file. Section names + * are interpreted by elf_bpf loader + */ +#define SEC(NAME) __attribute__((section(NAME), used)) + /* helper functions called from eBPF programs written in C */ static void *(*bpf_map_lookup_elem)(void *map, const void *key) = (void *) BPF_FUNC_map_lookup_elem; @@ -256,6 +258,12 @@ struct bpf_map_def { unsigned int numa_node; }; +#else + +#include + +#endif + #define BPF_ANNOTATE_KV_PAIR(name, type_key, type_val) \ struct ____btf_map_##name { \ type_key key; \ diff --git a/tools/testing/selftests/bpf/progs/test_tc_edt.c b/tools/testing/selftests/bpf/progs/test_tc_edt.c index 3af64c4..0961415 100644 --- a/tools/testing/selftests/bpf/progs/test_tc_edt.c +++ b/tools/testing/selftests/bpf/progs/test_tc_edt.c @@ -2,6 +2,7 @@ #include #include #include +#include #include #include #include -- 2.7.4