link: add StructOpsMap support

examples/scx/main.go

@@ -0,0 +1,42 @@
+package main
+
+// This program demonstrates attaching an eBPF program to sched_ext
+
+import (
+	"log"
+	"os"
+	"os/signal"
+	"syscall"
+
+	"github.com/cilium/ebpf/link"
+	"github.com/cilium/ebpf/rlimit"
+)
+
+//go:generate go run github.com/cilium/ebpf/cmd/bpf2go -no-global-types -tags linux bpf sched.c -- -I../headers
+
+func main() {
+	if err := rlimit.RemoveMemlock(); err != nil {
+		log.Fatal(err)
+	}
+
+	objs := bpfObjects{}
+	if err := loadBpfObjects(&objs, nil); err != nil {
+		log.Fatalf("loading objects: %v", err)
+	}
+	defer objs.Close()
+
+	m := objs.Scx
+	l, err := link.AttachStructOps(m)
+	if err != nil {
+		log.Fatalf("Failed to attach sched_ext: %s", err)
+	}
+	defer l.DetachStructOps()
+
+	log.Println("Successfully attached sched_ext struct operations")
+
+	stopper := make(chan os.Signal, 1)
+	signal.Notify(stopper, os.Interrupt, syscall.SIGTERM)
+	log.Print("Press Ctrl+C to stop...")
+
+	<-stopper
+}

examples/scx/sched.c

@@ -0,0 +1,59 @@
+// go:build ignore
+
+#include "common.h"
+
+char __license[] SEC("license") = "Dual MIT/GPL";
+
+struct sched_ext_ops {
+	__s32 (*init)(void);
+	void (*runnable)(void *, __u64);
+	void (*running)(void *);
+	void (*stopping)(void *, __u8);
+	void (*quiescent)(void *, __u64);
+	__u8 (*yield)(void *, void *);
+	__u32 timeout_ms;
+	char name[128];
+};
+
+SEC("struct_ops/scx_runnable")
+void scx_runnable(void *p, __u64 enq_flags) {
+	bpf_printk("scheduler runnable\n");
+};
+
+SEC("struct_ops/scx_running")
+void scx_running(void *p) {
+	bpf_printk("scheduler running\n");
+};
+
+SEC("struct_ops/scx_stopping")
+void scx_stopping(void *p, __u8 runnable) {
+	bpf_printk("scheduler stopping\n");
+};
+
+SEC("struct_ops/scx_quiescent")
+void scx_quiescent(void *p, __u64 deq_flags) {
+	bpf_printk("scheduler quiescent\n");
+};
+
+SEC("struct_ops/scx_yield")
+void scx_yield(void *from, void *to) {
+	bpf_printk("scheduler yield\n");
+};
+
+SEC("struct_ops.s/scx_init")
+int scx_init(void) {
+	bpf_printk("scheduler init\n");
+	return 0;
+};
+
+SEC(".struct_ops.link")
+struct sched_ext_ops scx = {
+	.init       = (void *)scx_init,
+	.running    = (void *)scx_running,
+	.runnable   = (void *)scx_runnable,
+	.stopping   = (void *)scx_stopping,
+	.quiescent  = (void *)scx_quiescent,
+	.yield      = (void *)scx_yield,
+	.timeout_ms = 10000U,
+	.name       = "scx",
+};