Commit 2326ff8d authored by Alexei Starovoitov's avatar Alexei Starovoitov
Browse files

Merge branch 'Future-proof more tricky libbpf APIs' 



Andrii Nakryiko says:

====================

This patch set continues the work of revamping libbpf APIs that are not
extensible, as they were added before we figured out all the intricacies of
building APIs that can preserve ABI compatibility (both backward and forward).

What makes them tricky is that (most of) these APIs are actively used by
multiple applications, so we need to be careful about refactoring them. See
individual patches for details, but the general approach is similar to
previous bpf_prog_load() API revamp. The biggest different and complexity is
in changing btf_dump__new(), because function overloading through macro magic
doesn't work based on number of arguments, as both new and old APIs have
4 arguments. Because of that, another overloading approach is taken; overload
happens based on argument types.

I've validated manually (by using local test_progs-shared flavor that is
compiling test_progs against libbpf as a shared library) that compiling "old
application" (selftests before being adapted to using new variants of revamped
APIs) are compiled and successfully run against newest libbpf version as well
as the older libbpf version (provided no new variants are used). All these
scenarios seem to be working as expected.

v1->v2:
  - add explicit printf_fn NULL check in btf_dump__new() (Alexei);
  - replaced + with || in __builtin_choose_expr() (Alexei);
  - dropped test_progs-shared flavor (Alexei).
====================

Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parents 3a75111d 164b04f2

tools/bpf/bpftool/Makefile

+8 −8
Original line number Diff line number Diff line
@@ -177,7 +177,8 @@ $(OUTPUT)%.bpf.o: skeleton/%.bpf.c $(OUTPUT)vmlinux.h $(LIBBPF) 
		-I$(if $(OUTPUT),$(OUTPUT),.) \

		-I$(srctree)/tools/include/uapi/ \

		-I$(LIBBPF_INCLUDE) \

		-g -O2 -Wall -target bpf -c $< -o $@ && $(LLVM_STRIP) -g $@

		-g -O2 -Wall -target bpf -c $< -o $@

	$(Q)$(LLVM_STRIP) -g $@



$(OUTPUT)%.skel.h: $(OUTPUT)%.bpf.o $(BPFTOOL_BOOTSTRAP)

	$(QUIET_GEN)$(BPFTOOL_BOOTSTRAP) gen skeleton $< > $@
@@ -192,10 +193,10 @@ endif 
CFLAGS += $(if $(BUILD_BPF_SKELS),,-DBPFTOOL_WITHOUT_SKELETONS)



$(BOOTSTRAP_OUTPUT)disasm.o: $(srctree)/kernel/bpf/disasm.c

	$(QUIET_CC)$(HOSTCC) $(CFLAGS) -c -MMD -o $@ $<

	$(QUIET_CC)$(HOSTCC) $(CFLAGS) -c -MMD $< -o $@



$(OUTPUT)disasm.o: $(srctree)/kernel/bpf/disasm.c

	$(QUIET_CC)$(CC) $(CFLAGS) -c -MMD -o $@ $<

	$(QUIET_CC)$(CC) $(CFLAGS) -c -MMD $< -o $@



$(OUTPUT)feature.o:

ifneq ($(feature-zlib), 1)
@@ -203,17 +204,16 @@ ifneq ($(feature-zlib), 1) 
endif



$(BPFTOOL_BOOTSTRAP): $(BOOTSTRAP_OBJS) $(LIBBPF_BOOTSTRAP)

	$(QUIET_LINK)$(HOSTCC) $(CFLAGS) $(LDFLAGS) -o $@ $(BOOTSTRAP_OBJS) \

		$(LIBS_BOOTSTRAP)

	$(QUIET_LINK)$(HOSTCC) $(CFLAGS) $(LDFLAGS) $(BOOTSTRAP_OBJS) $(LIBS_BOOTSTRAP) -o $@



$(OUTPUT)bpftool: $(OBJS) $(LIBBPF)

	$(QUIET_LINK)$(CC) $(CFLAGS) $(LDFLAGS) -o $@ $(OBJS) $(LIBS)

	$(QUIET_LINK)$(CC) $(CFLAGS) $(LDFLAGS) $(OBJS) $(LIBS) -o $@



$(BOOTSTRAP_OUTPUT)%.o: %.c $(LIBBPF_INTERNAL_HDRS) | $(BOOTSTRAP_OUTPUT)

	$(QUIET_CC)$(HOSTCC) $(CFLAGS) -c -MMD -o $@ $<

	$(QUIET_CC)$(HOSTCC) $(CFLAGS) -c -MMD $< -o $@



$(OUTPUT)%.o: %.c

	$(QUIET_CC)$(CC) $(CFLAGS) -c -MMD -o $@ $<

	$(QUIET_CC)$(CC) $(CFLAGS) -c -MMD $< -o $@



feature-detect-clean:

	$(call QUIET_CLEAN, feature-detect)

tools/bpf/bpftool/btf.c

+1 −1
Original line number Diff line number Diff line
@@ -418,7 +418,7 @@ static int dump_btf_c(const struct btf *btf, 
	struct btf_dump *d;

	int err = 0, i;



	d = btf_dump__new(btf, NULL, NULL, btf_dump_printf);

	d = btf_dump__new(btf, btf_dump_printf, NULL, NULL);

	if (IS_ERR(d))

		return PTR_ERR(d);

tools/bpf/bpftool/gen.c

+1 −1
Original line number Diff line number Diff line
@@ -218,7 +218,7 @@ static int codegen_datasecs(struct bpf_object *obj, const char *obj_name) 
	char sec_ident[256], map_ident[256];

	int i, err = 0;



	d = btf_dump__new(btf, NULL, NULL, codegen_btf_dump_printf);

	d = btf_dump__new(btf, codegen_btf_dump_printf, NULL, NULL);

	if (IS_ERR(d))

		return PTR_ERR(d);

tools/bpf/bpftool/map_perf_ring.c

+3 −6
Original line number Diff line number Diff line
@@ -124,7 +124,7 @@ int do_event_pipe(int argc, char **argv) 
		.wakeup_events = 1,

	};

	struct bpf_map_info map_info = {};

	struct perf_buffer_raw_opts opts = {};

	LIBBPF_OPTS(perf_buffer_raw_opts, opts);

	struct event_pipe_ctx ctx = {

		.all_cpus = true,

		.cpu = -1,
@@ -190,14 +190,11 @@ int do_event_pipe(int argc, char **argv) 
		ctx.idx = 0;

	}



	opts.attr = &perf_attr;

	opts.event_cb = print_bpf_output;

	opts.ctx = &ctx;

	opts.cpu_cnt = ctx.all_cpus ? 0 : 1;

	opts.cpus = &ctx.cpu;

	opts.map_keys = &ctx.idx;



	pb = perf_buffer__new_raw(map_fd, MMAP_PAGE_CNT, &opts);

	pb = perf_buffer__new_raw(map_fd, MMAP_PAGE_CNT, &perf_attr,

				  print_bpf_output, &ctx, &opts);

	err = libbpf_get_error(pb);

	if (err) {

		p_err("failed to create perf buffer: %s (%d)",

tools/bpf/runqslower/runqslower.c

+2 −4
Original line number Diff line number Diff line
@@ -123,7 +123,6 @@ int main(int argc, char **argv) 
		.parser = parse_arg,

		.doc = argp_program_doc,

	};

	struct perf_buffer_opts pb_opts;

	struct perf_buffer *pb = NULL;

	struct runqslower_bpf *obj;

	int err;
@@ -165,9 +164,8 @@ int main(int argc, char **argv) 
	printf("Tracing run queue latency higher than %llu us\n", env.min_us);

	printf("%-8s %-16s %-6s %14s\n", "TIME", "COMM", "PID", "LAT(us)");



	pb_opts.sample_cb = handle_event;

	pb_opts.lost_cb = handle_lost_events;

	pb = perf_buffer__new(bpf_map__fd(obj->maps.events), 64, &pb_opts);

	pb = perf_buffer__new(bpf_map__fd(obj->maps.events), 64,

			      handle_event, handle_lost_events, NULL, NULL);

	err = libbpf_get_error(pb);

	if (err) {

		pb = NULL;