sysinfo: support basic entries

Change-Id: I27f3e55058cc29f895831a1dddfafbc8585746a5
refs: #1389

kernel/syscall.c

@@ -6708,6 +6708,27 @@ SYSCALL_DECLARE(getrusage)
 	return 0;
 }
 
+SYSCALL_DECLARE(sysinfo)
+{
+	struct sysinfo *sysinfo = (struct sysinfo *)ihk_mc_syscall_arg0(ctx);
+	struct sysinfo __sysinfo;
+	int ret = 0;
+
+	memset(&__sysinfo, '\0', sizeof(struct sysinfo));
+
+	__sysinfo.totalram = rusage_get_total_memory();
+	__sysinfo.freeram = rusage_get_free_memory();
+	__sysinfo.mem_unit = 1; // always one unit for McKernel
+
+	if (copy_to_user(sysinfo, &__sysinfo, sizeof(struct sysinfo))) {
+		ret = -EFAULT;
+		goto out;
+	}
+
+out:
+	return ret;
+}
+
 extern int ptrace_traceme(void);
 extern void set_single_step(struct thread *thread);