lkl: add experimental rump syscall proxy support

The code is not built as-is but put an implementation using rump syscall
proxy which makes an LKL application communicate with outside of the
process.

Signed-off-by: Hajime Tazaki <thehajime@gmail.com>

Author: thehajime

arch/lkl/include/asm/Kbuild

@@ -70,7 +70,6 @@ generic-y += tlb.h
 generic-y += tlbflush.h
 generic-y += topology.h
 generic-y += trace_clock.h
-generic-y += uaccess.h
 generic-y += unaligned.h
 generic-y += vga.h
 generic-y += word-at-a-time.h

arch/lkl/include/asm/thread_info.h

@@ -22,6 +22,7 @@ struct thread_info {
 	bool dead;
 	lkl_thread_t tid;
 	struct task_struct *prev_sched;
+	void *rump_client;	/* for syscall proxy */
 	unsigned long stackend;
 };
 

arch/lkl/include/asm/uaccess.h

@@ -0,0 +1,70 @@
+#ifndef _ASM_LKL_UACCESS_H
+#define _ASM_LKL_UACCESS_H
+
+#include <linux/compiler.h>
+#include <linux/types.h>
+#include <linux/irqflags.h>
+#include <linux/string.h>
+#include <asm/errno.h>
+#include <asm/thread_info.h>
+
+#ifdef ENABLE_SYSPROXY
+#include <rump/rumpuser.h>
+#endif
+
+#define __access_ok(addr, size) (1)
+
+/* handle rump remote client */
+static inline __must_check long __copy_from_user(void *to,
+		const void __user *from, unsigned long n)
+{
+	int error = 0;
+	struct thread_info *ti;
+
+	ti = current_thread_info();
+
+	if (unlikely(from == NULL && n))
+		return -EFAULT;
+
+	if (!ti->rump_client) {
+		memcpy(to, from, n);
+	} else if (n) {
+#ifdef ENABLE_SYSPROXY
+		error = rumpuser_sp_copyin(ti->rump_client, from, to, n);
+#else
+		;
+#endif
+	}
+
+	return error;
+}
+#define __copy_from_user(to, from, n) __copy_from_user(to, from, n)
+
+static inline __must_check long __copy_to_user(void __user *to,
+		const void *from, unsigned long n)
+{
+	int error = 0;
+	struct thread_info *ti;
+
+	ti = current_thread_info();
+
+	if (unlikely(to == NULL && n))
+		return -EFAULT;
+
+	if (!ti->rump_client) {
+		memcpy(to, from, n);
+	} else if (n) {
+#ifdef ENABLE_SYSPROXY
+		error = rumpuser_sp_copyout(ti->rump_client, from, to, n);
+#else
+		;
+#endif
+	}
+
+	return error;
+}
+#define __copy_to_user(to, from, n) __copy_to_user(to, from, n)
+
+#include <asm-generic/uaccess.h>
+
+#endif /* _ASM_LKL_UACCESS_H */

tools/lkl/lib/rump-sysproxy.c

@@ -0,0 +1,29 @@
+/*
+ * Rump system call proxy interface for Linux
+ * Copyright (c) 2015 Hajime Tazaki
+ *
+ * Author: Hajime Tazaki <thehajime@gmail.com>
+ */
+
+#include <linux/stddef.h>
+#include <linux/types.h>
+#include <generated/utsrelease.h>
+
+#ifdef ENABLE_SYSPROXY
+#include "rump.h"
+
+int rump_init_server(const char *url)
+{
+	return rumpuser_sp_init(url, "Linux", UTS_RELEASE, "libos");
+}
+
+void rump_sysproxy_init(void)
+{
+	rump_init_server("unix:///tmp/rump-server");
+}
+
+void rump_sysproxy_fini(void)
+{
+	rumpuser_sp_fini(NULL);
+}
+#endif

tools/lkl/lib/rump.h

@@ -15,6 +15,9 @@ void rump_sysproxy_init(void);
 void rump_sysproxy_fini(void);
 
 extern const struct rumpuser_hyperup hyp;
+#ifdef ENABLE_SYSPROXY
+extern struct rump_sysproxy_ops rump_sysproxy_ops;
+#endif
 
 int rump_pci_irq_request(struct irq_data *data);
 void rump_pci_irq_release(struct irq_data *data);