[PATCH] perf trace: Split BPF skel code to util/trace_augment.c

[PATCH] perf trace: Split BPF skel code to util/trace_augment.c

[Namhyung Kim]

And make builtin-trace.c less conditional.  Dummy functions will be
called when BUILD_BPF_SKEL=0 is used.  This makes the builtin-trace.c
slightly smaller and simpler by removing the skeleton and its helpers.

The conditional guard of trace__init_syscalls_bpf_prog_array_maps() is
changed from the HAVE_BPF_SKEL to HAVE_LIBBPF_SUPPORT as it doesn't
have a skeleton in the code directly.  And a dummy function is added so
that it can be called unconditionally.  The function will succeed only
if the both conditions are true.

Do not include trace_augment.h from the BPF code and move the definition
of TRACE_AUG_MAX_BUF to the BPF directly.

Cc: Howard Chu <howardchu95@gmail.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
---
 tools/perf/builtin-trace.c                    | 187 +++++-------------
 tools/perf/util/Build                         |   1 +
 .../bpf_skel/augmented_raw_syscalls.bpf.c     |   3 +-
 tools/perf/util/trace_augment.c               | 143 ++++++++++++++
 tools/perf/util/trace_augment.h               |  62 +++++-
 5 files changed, 255 insertions(+), 141 deletions(-)
 create mode 100644 tools/perf/util/trace_augment.c

diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c
index 809b4d5b0a8a4ddc..3f3f6fadef0a128f 100644
--- a/tools/perf/builtin-trace.c
+++ b/tools/perf/builtin-trace.c
@@ -20,9 +20,6 @@
 #include <bpf/bpf.h>
 #include <bpf/libbpf.h>
 #include <bpf/btf.h>
-#ifdef HAVE_BPF_SKEL
-#include "bpf_skel/augmented_raw_syscalls.skel.h"
-#endif
 #endif
 #include "util/bpf_map.h"
 #include "util/rlimit.h"
@@ -155,9 +152,6 @@ struct trace {
 				*bpf_output;
 		}		events;
 	} syscalls;
-#ifdef HAVE_BPF_SKEL
-	struct augmented_raw_syscalls_bpf *skel;
-#endif
 #ifdef HAVE_LIBBPF_SUPPORT
 	struct btf		*btf;
 #endif
@@ -3699,7 +3693,10 @@ static int trace__set_ev_qualifier_tp_filter(struct trace *trace)
 	goto out;
 }
 
-#ifdef HAVE_BPF_SKEL
+#ifdef HAVE_LIBBPF_SUPPORT
+
+static struct bpf_program *unaugmented_prog;
+
 static int syscall_arg_fmt__cache_btf_struct(struct syscall_arg_fmt *arg_fmt, struct btf *btf, char *type)
 {
        int id;
@@ -3717,26 +3714,8 @@ static int syscall_arg_fmt__cache_btf_struct(struct syscall_arg_fmt *arg_fmt, st
        return 0;
 }
 
-static struct bpf_program *trace__find_bpf_program_by_title(struct trace *trace, const char *name)
-{
-	struct bpf_program *pos, *prog = NULL;
-	const char *sec_name;
-
-	if (trace->skel->obj == NULL)
-		return NULL;
-
-	bpf_object__for_each_program(pos, trace->skel->obj) {
-		sec_name = bpf_program__section_name(pos);
-		if (sec_name && !strcmp(sec_name, name)) {
-			prog = pos;
-			break;
-		}
-	}
-
-	return prog;
-}
-
-static struct bpf_program *trace__find_syscall_bpf_prog(struct trace *trace, struct syscall *sc,
+static struct bpf_program *trace__find_syscall_bpf_prog(struct trace *trace __maybe_unused,
+							struct syscall *sc,
 							const char *prog_name, const char *type)
 {
 	struct bpf_program *prog;
@@ -3744,19 +3723,19 @@ static struct bpf_program *trace__find_syscall_bpf_prog(struct trace *trace, str
 	if (prog_name == NULL) {
 		char default_prog_name[256];
 		scnprintf(default_prog_name, sizeof(default_prog_name), "tp/syscalls/sys_%s_%s", type, sc->name);
-		prog = trace__find_bpf_program_by_title(trace, default_prog_name);
+		prog = augmented_syscalls__find_by_title(default_prog_name);
 		if (prog != NULL)
 			goto out_found;
 		if (sc->fmt && sc->fmt->alias) {
 			scnprintf(default_prog_name, sizeof(default_prog_name), "tp/syscalls/sys_%s_%s", type, sc->fmt->alias);
-			prog = trace__find_bpf_program_by_title(trace, default_prog_name);
+			prog = augmented_syscalls__find_by_title(default_prog_name);
 			if (prog != NULL)
 				goto out_found;
 		}
 		goto out_unaugmented;
 	}
 
-	prog = trace__find_bpf_program_by_title(trace, prog_name);
+	prog = augmented_syscalls__find_by_title(prog_name);
 
 	if (prog != NULL) {
 out_found:
@@ -3766,7 +3745,7 @@ static struct bpf_program *trace__find_syscall_bpf_prog(struct trace *trace, str
 	pr_debug("Couldn't find BPF prog \"%s\" to associate with syscalls:sys_%s_%s, not augmenting it\n",
 		 prog_name, type, sc->name);
 out_unaugmented:
-	return trace->skel->progs.syscall_unaugmented;
+	return unaugmented_prog;
 }
 
 static void trace__init_syscall_bpf_progs(struct trace *trace, int e_machine, int id)
@@ -3783,13 +3762,13 @@ static void trace__init_syscall_bpf_progs(struct trace *trace, int e_machine, in
 static int trace__bpf_prog_sys_enter_fd(struct trace *trace, int e_machine, int id)
 {
 	struct syscall *sc = trace__syscall_info(trace, NULL, e_machine, id);
-	return sc ? bpf_program__fd(sc->bpf_prog.sys_enter) : bpf_program__fd(trace->skel->progs.syscall_unaugmented);
+	return sc ? bpf_program__fd(sc->bpf_prog.sys_enter) : bpf_program__fd(unaugmented_prog);
 }
 
 static int trace__bpf_prog_sys_exit_fd(struct trace *trace, int e_machine, int id)
 {
 	struct syscall *sc = trace__syscall_info(trace, NULL, e_machine, id);
-	return sc ? bpf_program__fd(sc->bpf_prog.sys_exit) : bpf_program__fd(trace->skel->progs.syscall_unaugmented);
+	return sc ? bpf_program__fd(sc->bpf_prog.sys_exit) : bpf_program__fd(unaugmented_prog);
 }
 
 static int trace__bpf_sys_enter_beauty_map(struct trace *trace, int e_machine, int key, unsigned int *beauty_array)
@@ -3899,7 +3878,7 @@ static struct bpf_program *trace__find_usable_bpf_prog_entry(struct trace *trace
 		bool is_candidate = false;
 
 		if (pair == NULL || pair->id == sc->id ||
-		    pair->bpf_prog.sys_enter == trace->skel->progs.syscall_unaugmented)
+		    pair->bpf_prog.sys_enter == unaugmented_prog)
 			continue;
 
 		for (field = sc->args, candidate_field = pair->args;
@@ -3965,7 +3944,7 @@ static struct bpf_program *trace__find_usable_bpf_prog_entry(struct trace *trace
 		 */
 		if (pair_prog == NULL) {
 			pair_prog = trace__find_syscall_bpf_prog(trace, pair, pair->fmt ? pair->fmt->bpf_prog_name.sys_enter : NULL, "enter");
-			if (pair_prog == trace->skel->progs.syscall_unaugmented)
+			if (pair_prog == unaugmented_prog)
 				goto next_candidate;
 		}
 
@@ -3981,12 +3960,17 @@ static struct bpf_program *trace__find_usable_bpf_prog_entry(struct trace *trace
 
 static int trace__init_syscalls_bpf_prog_array_maps(struct trace *trace, int e_machine)
 {
-	int map_enter_fd = bpf_map__fd(trace->skel->maps.syscalls_sys_enter);
-	int map_exit_fd  = bpf_map__fd(trace->skel->maps.syscalls_sys_exit);
-	int beauty_map_fd = bpf_map__fd(trace->skel->maps.beauty_map_enter);
+	int map_enter_fd;
+	int map_exit_fd;
+	int beauty_map_fd;
 	int err = 0;
 	unsigned int beauty_array[6];
 
+	if (augmented_syscalls__get_map_fds(&map_enter_fd, &map_exit_fd, &beauty_map_fd) < 0)
+		return -1;
+
+	unaugmented_prog = augmented_syscalls__unaugmented();
+
 	for (int i = 0, num_idx = syscalltbl__num_idx(e_machine); i < num_idx; ++i) {
 		int prog_fd, key = syscalltbl__id_at_idx(e_machine, i);
 
@@ -4056,7 +4040,7 @@ static int trace__init_syscalls_bpf_prog_array_maps(struct trace *trace, int e_m
 		 * For now we're just reusing the sys_enter prog, and if it
 		 * already has an augmenter, we don't need to find one.
 		 */
-		if (sc->bpf_prog.sys_enter != trace->skel->progs.syscall_unaugmented)
+		if (sc->bpf_prog.sys_enter != unaugmented_prog)
 			continue;
 
 		/*
@@ -4081,7 +4065,13 @@ static int trace__init_syscalls_bpf_prog_array_maps(struct trace *trace, int e_m
 
 	return err;
 }
-#endif // HAVE_BPF_SKEL
+#else // !HAVE_LIBBPF_SUPPORT
+static int trace__init_syscalls_bpf_prog_array_maps(struct trace *trace __maybe_unused,
+						    int e_machine __maybe_unused)
+{
+	return -1;
+}
+#endif // HAVE_LIBBPF_SUPPORT
 
 static int trace__set_ev_qualifier_filter(struct trace *trace)
 {
@@ -4090,24 +4080,6 @@ static int trace__set_ev_qualifier_filter(struct trace *trace)
 	return 0;
 }
 
-static int bpf_map__set_filter_pids(struct bpf_map *map __maybe_unused,
-				    size_t npids __maybe_unused, pid_t *pids __maybe_unused)
-{
-	int err = 0;
-#ifdef HAVE_LIBBPF_SUPPORT
-	bool value = true;
-	int map_fd = bpf_map__fd(map);
-	size_t i;
-
-	for (i = 0; i < npids; ++i) {
-		err = bpf_map_update_elem(map_fd, &pids[i], &value, BPF_ANY);
-		if (err)
-			break;
-	}
-#endif
-	return err;
-}
-
 static int trace__set_filter_loop_pids(struct trace *trace)
 {
 	unsigned int nr = 1, err;
@@ -4133,8 +4105,8 @@ static int trace__set_filter_loop_pids(struct trace *trace)
 	}
 
 	err = evlist__append_tp_filter_pids(trace->evlist, nr, pids);
-	if (!err && trace->filter_pids.map)
-		err = bpf_map__set_filter_pids(trace->filter_pids.map, nr, pids);
+	if (!err)
+		err = augmented_syscalls__set_filter_pids(nr, pids);
 
 	return err;
 }
@@ -4151,8 +4123,8 @@ static int trace__set_filter_pids(struct trace *trace)
 	if (trace->filter_pids.nr > 0) {
 		err = evlist__append_tp_filter_pids(trace->evlist, trace->filter_pids.nr,
 						    trace->filter_pids.entries);
-		if (!err && trace->filter_pids.map) {
-			err = bpf_map__set_filter_pids(trace->filter_pids.map, trace->filter_pids.nr,
+		if (!err) {
+			err = augmented_syscalls__set_filter_pids(trace->filter_pids.nr,
 						       trace->filter_pids.entries);
 		}
 	} else if (perf_thread_map__pid(trace->evlist->core.threads, 0) == -1) {
@@ -4475,41 +4447,18 @@ static int trace__run(struct trace *trace, int argc, const char **argv)
 	err = evlist__open(evlist);
 	if (err < 0)
 		goto out_error_open;
-#ifdef HAVE_BPF_SKEL
-	if (trace->syscalls.events.bpf_output) {
-		struct perf_cpu cpu;
 
-		/*
-		 * Set up the __augmented_syscalls__ BPF map to hold for each
-		 * CPU the bpf-output event's file descriptor.
-		 */
-		perf_cpu_map__for_each_cpu(cpu, i, trace->syscalls.events.bpf_output->core.cpus) {
-			int mycpu = cpu.cpu;
-
-			bpf_map__update_elem(trace->skel->maps.__augmented_syscalls__,
-					&mycpu, sizeof(mycpu),
-					xyarray__entry(trace->syscalls.events.bpf_output->core.fd,
-						       mycpu, 0),
-					sizeof(__u32), BPF_ANY);
-		}
-	}
+	augmented_syscalls__setup_bpf_output();
 
-	if (trace->skel)
-		trace->filter_pids.map = trace->skel->maps.pids_filtered;
-#endif
 	err = trace__set_filter_pids(trace);
 	if (err < 0)
 		goto out_error_mem;
 
-#ifdef HAVE_BPF_SKEL
-	if (trace->skel && trace->skel->progs.sys_enter) {
-		/*
-		 * TODO: Initialize for all host binary machine types, not just
-		 * those matching the perf binary.
-		 */
-		trace__init_syscalls_bpf_prog_array_maps(trace, EM_HOST);
-	}
-#endif
+	/*
+	 * TODO: Initialize for all host binary machine types, not just
+	 * those matching the perf binary.
+	 */
+	trace__init_syscalls_bpf_prog_array_maps(trace, EM_HOST);
 
 	if (trace->ev_qualifier_ids.nr > 0) {
 		err = trace__set_ev_qualifier_filter(trace);
@@ -5368,18 +5317,6 @@ static void trace__exit(struct trace *trace)
 #endif
 }
 
-#ifdef HAVE_BPF_SKEL
-static int bpf__setup_bpf_output(struct evlist *evlist)
-{
-	int err = parse_event(evlist, "bpf-output/no-inherit=1,name=__augmented_syscalls__/");
-
-	if (err)
-		pr_debug("ERROR: failed to create the \"__augmented_syscalls__\" bpf-output event\n");
-
-	return err;
-}
-#endif
-
 int cmd_trace(int argc, const char **argv)
 {
 	const char *trace_usage[] = {
@@ -5575,7 +5512,6 @@ int cmd_trace(int argc, const char **argv)
 				       "cgroup monitoring only available in system-wide mode");
 	}
 
-#ifdef HAVE_BPF_SKEL
 	if (!trace.trace_syscalls)
 		goto skip_augmentation;
 
@@ -5594,42 +5530,17 @@ int cmd_trace(int argc, const char **argv)
 			goto skip_augmentation;
 	}
 
-	trace.skel = augmented_raw_syscalls_bpf__open();
-	if (!trace.skel) {
-		pr_debug("Failed to open augmented syscalls BPF skeleton");
-	} else {
-		/*
-		 * Disable attaching the BPF programs except for sys_enter and
-		 * sys_exit that tail call into this as necessary.
-		 */
-		struct bpf_program *prog;
+	err = augmented_syscalls__prepare();
+	if (err < 0)
+		goto skip_augmentation;
 
-		bpf_object__for_each_program(prog, trace.skel->obj) {
-			if (prog != trace.skel->progs.sys_enter && prog != trace.skel->progs.sys_exit)
-				bpf_program__set_autoattach(prog, /*autoattach=*/false);
-		}
+	trace__add_syscall_newtp(&trace);
 
-		err = augmented_raw_syscalls_bpf__load(trace.skel);
+	err = augmented_syscalls__create_bpf_output(trace.evlist);
+	if (err == 0)
+		trace.syscalls.events.bpf_output = evlist__last(trace.evlist);
 
-		if (err < 0) {
-			libbpf_strerror(err, bf, sizeof(bf));
-			pr_debug("Failed to load augmented syscalls BPF skeleton: %s\n", bf);
-		} else {
-			augmented_raw_syscalls_bpf__attach(trace.skel);
-			trace__add_syscall_newtp(&trace);
-		}
-	}
-
-	err = bpf__setup_bpf_output(trace.evlist);
-	if (err) {
-		libbpf_strerror(err, bf, sizeof(bf));
-		pr_err("ERROR: Setup BPF output event failed: %s\n", bf);
-		goto out;
-	}
-	trace.syscalls.events.bpf_output = evlist__last(trace.evlist);
-	assert(evsel__name_is(trace.syscalls.events.bpf_output, "__augmented_syscalls__"));
 skip_augmentation:
-#endif
 	err = -1;
 
 	if (trace.trace_pgfaults) {
@@ -5812,8 +5723,6 @@ int cmd_trace(int argc, const char **argv)
 		fclose(trace.output);
 out:
 	trace__exit(&trace);
-#ifdef HAVE_BPF_SKEL
-	augmented_raw_syscalls_bpf__destroy(trace.skel);
-#endif
+	augmented_syscalls__cleanup();
 	return err;
 }
diff --git a/tools/perf/util/Build b/tools/perf/util/Build
index 4f7f072fa222ba80..7113dd237e3387db 100644
--- a/tools/perf/util/Build
+++ b/tools/perf/util/Build
@@ -175,6 +175,7 @@ perf-util-$(CONFIG_PERF_BPF_SKEL) += btf.o
 
 ifeq ($(CONFIG_TRACE),y)
   perf-util-$(CONFIG_PERF_BPF_SKEL) += bpf-trace-summary.o
+  perf-util-$(CONFIG_PERF_BPF_SKEL) += trace_augment.o
 endif
 
 ifeq ($(CONFIG_LIBTRACEEVENT),y)
diff --git a/tools/perf/util/bpf_skel/augmented_raw_syscalls.bpf.c b/tools/perf/util/bpf_skel/augmented_raw_syscalls.bpf.c
index e4352881e3faa602..cb86e261b4de0685 100644
--- a/tools/perf/util/bpf_skel/augmented_raw_syscalls.bpf.c
+++ b/tools/perf/util/bpf_skel/augmented_raw_syscalls.bpf.c
@@ -7,7 +7,6 @@
  */
 
 #include "vmlinux.h"
-#include "../trace_augment.h"
 
 #include <bpf/bpf_helpers.h>
 #include <linux/limits.h>
@@ -27,6 +26,8 @@
 
 #define MAX_CPUS  4096
 
+#define TRACE_AUG_MAX_BUF 32 /* for buffer augmentation in perf trace */
+
 /* bpf-output associated map */
 struct __augmented_syscalls__ {
 	__uint(type, BPF_MAP_TYPE_PERF_EVENT_ARRAY);
diff --git a/tools/perf/util/trace_augment.c b/tools/perf/util/trace_augment.c
new file mode 100644
index 0000000000000000..56ed17534caa4f3f
--- /dev/null
+++ b/tools/perf/util/trace_augment.c
@@ -0,0 +1,143 @@
+#include <bpf/libbpf.h>
+#include <internal/xyarray.h>
+
+#include "util/debug.h"
+#include "util/evlist.h"
+#include "util/trace_augment.h"
+
+#include "bpf_skel/augmented_raw_syscalls.skel.h"
+
+static struct augmented_raw_syscalls_bpf *skel;
+static struct evsel *bpf_output;
+
+int augmented_syscalls__prepare(void)
+{
+	struct bpf_program *prog;
+	char buf[128];
+	int err;
+
+	skel = augmented_raw_syscalls_bpf__open();
+	if (!skel) {
+		pr_debug("Failed to open augmented syscalls BPF skeleton\n");
+		return -errno;
+	}
+
+	/*
+	 * Disable attaching the BPF programs except for sys_enter and
+	 * sys_exit that tail call into this as necessary.
+	 */
+	bpf_object__for_each_program(prog, skel->obj) {
+		if (prog != skel->progs.sys_enter && prog != skel->progs.sys_exit)
+			bpf_program__set_autoattach(prog, /*autoattach=*/false);
+	}
+
+	err = augmented_raw_syscalls_bpf__load(skel);
+	if (err < 0) {
+		libbpf_strerror(err, buf, sizeof(buf));
+		pr_debug("Failed to load augmented syscalls BPF skeleton: %s\n", buf);
+		return err;
+	}
+
+	augmented_raw_syscalls_bpf__attach(skel);
+	return 0;
+}
+
+int augmented_syscalls__create_bpf_output(struct evlist *evlist)
+{
+	int err = parse_event(evlist, "bpf-output/no-inherit=1,name=__augmented_syscalls__/");
+
+	if (err) {
+		pr_err("ERROR: Setup BPF output event failed: %d\n", err);
+		return err;
+	}
+
+	bpf_output = evlist__last(evlist);
+	assert(evsel__name_is(bpf_output, "__augmented_syscalls__"));
+
+	return 0;
+}
+
+void augmented_syscalls__setup_bpf_output(void)
+{
+	struct perf_cpu cpu;
+	int i;
+
+	if (bpf_output == NULL)
+		return;
+
+	/*
+	 * Set up the __augmented_syscalls__ BPF map to hold for each
+	 * CPU the bpf-output event's file descriptor.
+	 */
+	perf_cpu_map__for_each_cpu(cpu, i, bpf_output->core.cpus) {
+		int mycpu = cpu.cpu;
+
+		bpf_map__update_elem(skel->maps.__augmented_syscalls__,
+				     &mycpu, sizeof(mycpu),
+				     xyarray__entry(bpf_output->core.fd,
+						    mycpu, 0),
+				     sizeof(__u32), BPF_ANY);
+	}
+}
+
+int augmented_syscalls__set_filter_pids(unsigned int nr, pid_t *pids)
+{
+	bool value = true;
+	int err = 0;
+
+	if (skel == NULL)
+		return 0;
+
+	for (size_t i = 0; i < nr; ++i) {
+		err = bpf_map__update_elem(skel->maps.pids_filtered, &pids[i],
+					   sizeof(*pids), &value, sizeof(value),
+					   BPF_ANY);
+		if (err)
+			break;
+	}
+	return err;
+}
+
+int augmented_syscalls__get_map_fds(int *enter_fd, int *exit_fd, int *beauty_fd)
+{
+	if (skel == NULL)
+		return -1;
+
+	*enter_fd = bpf_map__fd(skel->maps.syscalls_sys_enter);
+	*exit_fd  = bpf_map__fd(skel->maps.syscalls_sys_exit);
+	*beauty_fd = bpf_map__fd(skel->maps.beauty_map_enter);
+
+	if (*enter_fd < 0 || *exit_fd < 0 || *beauty_fd < 0) {
+		pr_err("Error: failed to get syscall or beauty map fd\n");
+		return -1;
+	}
+
+	return 0;
+}
+
+struct bpf_program *augmented_syscalls__unaugmented(void)
+{
+	return skel->progs.syscall_unaugmented;
+}
+
+struct bpf_program *augmented_syscalls__find_by_title(const char *name)
+{
+	struct bpf_program *pos;
+	const char *sec_name;
+
+	if (skel->obj == NULL)
+		return NULL;
+
+	bpf_object__for_each_program(pos, skel->obj) {
+		sec_name = bpf_program__section_name(pos);
+		if (sec_name && !strcmp(sec_name, name))
+			return pos;
+	}
+
+	return NULL;
+}
+
+void augmented_syscalls__cleanup(void)
+{
+	augmented_raw_syscalls_bpf__destroy(skel);
+}
diff --git a/tools/perf/util/trace_augment.h b/tools/perf/util/trace_augment.h
index 57a3e50459377983..4f729bc6775304b4 100644
--- a/tools/perf/util/trace_augment.h
+++ b/tools/perf/util/trace_augment.h
@@ -1,6 +1,66 @@
 #ifndef TRACE_AUGMENT_H
 #define TRACE_AUGMENT_H
 
-#define TRACE_AUG_MAX_BUF 32 /* for buffer augmentation in perf trace */
+#include <linux/compiler.h>
+
+struct bpf_program;
+struct evlist;
+
+#ifdef HAVE_BPF_SKEL
+
+int augmented_syscalls__prepare(void);
+int augmented_syscalls__create_bpf_output(struct evlist *evlist);
+void augmented_syscalls__setup_bpf_output(void);
+int augmented_syscalls__set_filter_pids(unsigned int nr, pid_t *pids);
+int augmented_syscalls__get_map_fds(int *enter_fd, int *exit_fd, int *beauty_fd);
+struct bpf_program *augmented_syscalls__find_by_title(const char *name);
+struct bpf_program *augmented_syscalls__unaugmented(void);
+void augmented_syscalls__cleanup(void);
+
+#else /* !HAVE_BPF_SKEL */
+
+static inline int augmented_syscalls__prepare(void)
+{
+	return -1;
+}
+
+static inline int augmented_syscalls__create_bpf_output(struct evlist *evlist __maybe_unused)
+{
+	return -1;
+}
+
+static inline void augmented_syscalls__setup_bpf_output(void)
+{
+}
+
+static inline int augmented_syscalls__set_filter_pids(unsigned int nr __maybe_unused,
+						      pid_t *pids __maybe_unused)
+{
+	return 0;
+}
+
+static inline int augmented_syscalls__get_map_fds(int *enter_fd __maybe_unused,
+						  int *exit_fd __maybe_unused,
+						  int *beauty_fd __maybe_unused)
+{
+	return -1;
+}
+
+static inline struct bpf_program *
+augmented_syscalls__find_by_title(const char *name __maybe_unused)
+{
+	return NULL;
+}
+
+static inline struct bpf_program *augmented_syscalls__unaugmented(void)
+{
+	return NULL;
+}
+
+static inline void augmented_syscalls__cleanup(void)
+{
+}
+
+#endif /* HAVE_BPF_SKEL */
 
 #endif
-- 
2.49.0

Re: [PATCH] perf trace: Split BPF skel code to util/trace_augment.c

[Howard Chu]

Hi Namhyung,

It does not apply, probably because the cgroup patch is merged
beforehand. Can you please rebase it so others can test it? Otherwise,
this patch looks good to me.

And sorry about the delay and breaking the promise to review it within
two days...

On Tue, Apr 29, 2025 at 11:06 PM Namhyung Kim <namhyung@kernel.org> wrote:
>
> And make builtin-trace.c less conditional.  Dummy functions will be
> called when BUILD_BPF_SKEL=0 is used.  This makes the builtin-trace.c
> slightly smaller and simpler by removing the skeleton and its helpers.
>
> The conditional guard of trace__init_syscalls_bpf_prog_array_maps() is
> changed from the HAVE_BPF_SKEL to HAVE_LIBBPF_SUPPORT as it doesn't
> have a skeleton in the code directly.  And a dummy function is added so
> that it can be called unconditionally.  The function will succeed only
> if the both conditions are true.
>
> Do not include trace_augment.h from the BPF code and move the definition
> of TRACE_AUG_MAX_BUF to the BPF directly.
>
> Cc: Howard Chu <howardchu95@gmail.com>
> Signed-off-by: Namhyung Kim <namhyung@kernel.org>

Reviewed-by: Howard Chu <howardchu95@gmail.com>

Thanks,
Howard