libbpf: add support for sleepable kprobe and uprobe programs

Add section mappings for uprobe.s and kprobe.s programs. The latter
cannot currently attach but they're still useful to open and load in
order to validate that prohibition.

Signed-off-by: Delyan Kratunov <delyank@fb.com>
Acked-by: Andrii Nakryiko <andrii@kernel.org>

Author: Delyan Kratunov

tools/lib/bpf/libbpf.c

@@ -8985,8 +8985,10 @@ static const struct bpf_sec_def section_defs[] = {
 	SEC_DEF("sk_reuseport",		SK_REUSEPORT, BPF_SK_REUSEPORT_SELECT, SEC_ATTACHABLE | SEC_SLOPPY_PFX),
 	SEC_DEF("kprobe+",		KPROBE,	0, SEC_NONE, attach_kprobe),
 	SEC_DEF("uprobe+",		KPROBE,	0, SEC_NONE, attach_uprobe),
+	SEC_DEF("uprobe.s+",		KPROBE,	0, SEC_SLEEPABLE, attach_uprobe),
 	SEC_DEF("kretprobe+",		KPROBE, 0, SEC_NONE, attach_kprobe),
 	SEC_DEF("uretprobe+",		KPROBE, 0, SEC_NONE, attach_uprobe),
+	SEC_DEF("uretprobe.s+",		KPROBE, 0, SEC_SLEEPABLE, attach_uprobe),
 	SEC_DEF("kprobe.multi+",	KPROBE,	BPF_TRACE_KPROBE_MULTI, SEC_NONE, attach_kprobe_multi),
 	SEC_DEF("kretprobe.multi+",	KPROBE,	BPF_TRACE_KPROBE_MULTI, SEC_NONE, attach_kprobe_multi),
 	SEC_DEF("usdt+",		KPROBE,	0, SEC_NONE, attach_usdt),
@@ -10737,6 +10739,7 @@ static int attach_kprobe(const struct bpf_program *prog, long cookie, struct bpf
 	else
 		func_name = prog->sec_name + sizeof("kprobe/") - 1;
 
+
 	n = sscanf(func_name, "%m[a-zA-Z0-9_.]+%li", &func, &offset);
 	if (n < 1) {
 		pr_warn("kprobe name is invalid: %s\n", func_name);
@@ -11262,7 +11265,8 @@ static int attach_uprobe(const struct bpf_program *prog, long cookie, struct bpf
 		break;
 	case 3:
 	case 4:
-		opts.retprobe = strcmp(probe_type, "uretprobe") == 0;
+		opts.retprobe = strcmp(probe_type, "uretprobe") == 0 ||
+				strcmp(probe_type, "uretprobe.s") == 0;
 		if (opts.retprobe && offset != 0) {
 			pr_warn("prog '%s': uretprobes do not support offset specification\n",
 				prog->name);