Build on Jeff Roberson's linker-set based dynamic per-CPU allocator

(DPCPU), as suggested by Peter Wemm, and implement a new per-virtual
network stack memory allocator.  Modify vnet to use the allocator
instead of monolithic global container structures (vinet, ...).  This
change solves many binary compatibility problems associated with
VIMAGE, and restores ELF symbols for virtualized global variables.

Each virtualized global variable exists as a "reference copy", and also
once per virtual network stack.  Virtualized global variables are
tagged at compile-time, placing the in a special linker set, which is
loaded into a contiguous region of kernel memory.  Virtualized global
variables in the base kernel are linked as normal, but those in modules
are copied and relocated to a reserved portion of the kernel's vnet
region with the help of a the kernel linker.

Virtualized global variables exist in per-vnet memory set up when the
network stack instance is created, and are initialized statically from
the reference copy.  Run-time access occurs via an accessor macro, which
converts from the current vnet and requested symbol to a per-vnet
address.  When "options VIMAGE" is not compiled into the kernel, normal
global ELF symbols will be used instead and indirection is avoided.

This change restores static initialization for network stack global
variables, restores support for non-global symbols and types, eliminates
the need for many subsystem constructors, eliminates large per-subsystem
structures that caused many binary compatibility issues both for
monitoring applications (netstat) and kernel modules, removes the
per-function INIT_VNET_*() macros throughout the stack, eliminates the
need for vnet_symmap ksym(2) munging, and eliminates duplicate
definitions of virtualized globals under VIMAGE_GLOBALS.

Bump __FreeBSD_version and update UPDATING.

Portions submitted by:  bz
Reviewed by:            bz, zec
Discussed with:         gnn, jamie, jeff, jhb, julian, sam
Suggested by:           peter
Approved by:            re (kensmith)

1 files changed, 113 insertions, 48 deletions

diff --git a/sys/net/vnet.h b/sys/net/vnet.h
index b5d2fbd..4b543e6 100644
--- a/sys/net/vnet.h
+++ b/sys/net/vnet.h
@@ -1,10 +1,6 @@
 /*-
- * Copyright (c) 2006-2008 University of Zagreb
- * Copyright (c) 2006-2008 FreeBSD Foundation
- *
- * This software was developed by the University of Zagreb and the
- * FreeBSD Foundation under sponsorship by the Stichting NLnet and the
- * FreeBSD Foundation.
+ * Copyright (c) 2009 Jeffrey Roberson <jeff@freebsd.org>
+ * Copyright (c) 2009 Robert N. M. Watson
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
@@ -30,62 +26,131 @@
  * $FreeBSD$
  */
 
+/*
+ * This is the virtual network stack memory allocator, which provides support
+ * for virtualized global variables via a special linker set, set_vnet.  When
+ * "options VIMAGE" isn't defined, virtualized global variables are compiled
+ * as normal globals.
+ */
+
 #ifndef _NET_VNET_H_
 #define	_NET_VNET_H_
 
-#include <net/if_var.h>
+#ifdef _KERNEL
+#ifdef VIMAGE
+
+#if defined(__arm__)
+__asm__(".section set_vnet, \"aw\", %progbits");
+#else
+__asm__(".section set_vnet, \"aw\", @progbits");
+#endif
+__asm__(".previous");
+
+#define	VNET_NAME(n)		vnet_entry_##n
+#define	VNET_DECLARE(t, n)	extern t VNET_NAME(n)
+#define	VNET_DEFINE(t, n)	t VNET_NAME(n) __section("set_vnet") __used
+#define	_VNET_PTR(b, n)		(__typeof(VNET_NAME(n))*)		\
+				    ((b) + (uintptr_t)&VNET_NAME(n))
+
+#define	_VNET_GET(b, n)		(*_VNET_PTR(b, n))
+#define	_VNET_SET(b, n, v)	(*_VNET_PTR(b, n) = v)
 
-struct ifindex_entry;
+/*
+ * Virtualized global variable accessor macros.
+ */
+#define	VNET_VNET_PTR(vnet, n)		_VNET_PTR((vnet)->vnet_data_base, n)
+#define	VNET_VNET_GET(vnet, n)		(*VNET_VNET_PTR((vnet), n))
+#define	VNET_VNET_SET(vnet, n, v)	((*VNET_VNET_PTR((vnet), n)) = v)
 
-struct vnet_net {
-	int			_if_index;
-	struct ifindex_entry *	_ifindex_table;
-	struct ifnethead	_ifnet;
-	struct ifgrouphead	_ifg_head;
+#define	VNET_PTR(n)		VNET_VNET_PTR(curvnet, n)
+#define	VNET_GET(n)		VNET_VNET_GET(curvnet, n)
+#define	VNET_SET(n, v)		VNET_VNET_SET(curvnet, n, v)
 
-	int			_if_indexlim;
+/*
+ * Sysctl variants for vnet-virtualized global variables.  Include
+ * <sys/sysctl.h> to expose these definitions.
+ *
+ * Note: SYSCTL_PROC() handler functions will need to resolve pointer
+ * arguments themselves, if required.
+ */
+#ifdef SYSCTL_OID
+int	vnet_sysctl_handle_int(SYSCTL_HANDLER_ARGS);
+int	vnet_sysctl_handle_opaque(SYSCTL_HANDLER_ARGS);
+int	vnet_sysctl_handle_string(SYSCTL_HANDLER_ARGS);
+int	vnet_sysctl_handle_uint(SYSCTL_HANDLER_ARGS);
 
-	struct ifnet *		_loif;
-	struct if_clone *	_lo_cloner;
-	struct ifc_simple_data *_lo_cloner_data;
+#define	SYSCTL_VNET_INT(parent, nbr, name, access, ptr, val, descr)	\
+	SYSCTL_OID(parent, nbr, name, CTLTYPE_INT|CTLFLAG_MPSAFE|(access), \
+	    ptr, val, vnet_sysctl_handle_int, "I", descr)
+#define	SYSCTL_VNET_PROC(parent, nbr, name, access, ptr, arg, handler,	\
+	    fmt, descr)							\
+	SYSCTL_OID(parent, nbr, name, access, ptr, arg, handler, fmt,	\
+	    descr)
+#define	SYSCTL_VNET_STRING(parent, nbr, name, access, arg, len, descr)	\
+	SYSCTL_OID(parent, nbr, name, CTLTYPE_STRING|(access), arg,	\
+	    len, vnet_sysctl_handle_string, "A", descr)
+#define	SYSCTL_VNET_STRUCT(parent, nbr, name, access, ptr, type, descr)	\
+	SYSCTL_OID(parent, nbr, name, CTLTYPE_OPAQUE|(access), ptr,	\
+	    sizeof(struct type), vnet_sysctl_handle_opaque, "S," #type,	\
+	    descr)
+#define	SYSCTL_VNET_UINT(parent, nbr, name, access, ptr, val, descr)	\
+	SYSCTL_OID(parent, nbr, name, CTLTYPE_UINT|CTLFLAG_MPSAFE|(access), \
+	    ptr, val, vnet_sysctl_handle_uint, "IU", descr)
+#endif /* SYSCTL_OID */
 
-	LIST_HEAD(, rawcb)	_rawcb_list;
+/*
+ * Interfaces from the kernel linker.
+ */
+void	*vnet_data_alloc(int size);
+void	 vnet_data_copy(void *start, int size);
+void	 vnet_data_free(void *start_arg, int size);
 
-	LIST_HEAD(, if_clone)	_if_cloners;
-	int			_if_cloners_count;
+/*
+ * Interfaces for vnet setup/teardown.
+ */
+struct vnet;
+void	 vnet_data_init(struct vnet *vnet);
+void	 vnet_data_destroy(struct vnet *vnet);
 
-	int			_ether_ipfw;
-};
+#else /* !VIMAGE */
 
-/* Size guard. See sys/vimage.h. */
-VIMAGE_CTASSERT(SIZEOF_vnet_net, sizeof(struct vnet_net));
+/*
+ * Versions of the VNET macros that compile to normal global variables and
+ * standard sysctl definitions.
+ */
+#define	VNET_NAME(n)		n
+#define	VNET_DECLARE(t, n)	extern t n
+#define	VNET_DEFINE(t, n)	t n
+#define	_VNET_PTR(b, n)		&VNET_NAME(n)
 
-#ifndef VIMAGE
-#ifndef VIMAGE_GLOBALS
-extern struct vnet_net vnet_net_0;
-#endif
-#endif
+#ifdef SYSCTL_OID
+#define	SYSCTL_VNET_INT(parent, nbr, name, access, ptr, val, descr)	\
+	SYSCTL_INT(parent, nbr, name, access, ptr, val, descr)
+#define	SYSCTL_VNET_PROC(parent, nbr, name, access, ptr, arg, handler,	\
+	    fmt, descr)							\
+	SYSCTL_PROC(parent, nbr, name, access, ptr, arg, handler, fmt,	\
+	    descr)
+#define	SYSCTL_VNET_STRING(parent, nbr, name, access, arg, len, descr)	\
+	SYSCTL_STRING(parent, nbr, name, access, arg, len, descr)
+#define	SYSCTL_VNET_STRUCT(parent, nbr, name, access, ptr, type, descr)	\
+	SYSCTL_STRUCT(parent, nbr, name, access, ptr, type, descr)
+#define	SYSCTL_VNET_UINT(parent, nbr, name, access, ptr, val, descr)	\
+	SYSCTL_UINT(parent, nbr, name, access, ptr, val, descr)
+#endif /* SYSCTL_OID */
 
 /*
- * Symbol translation macros
+ * Virtualized global variable accessor macros.
  */
-#define	INIT_VNET_NET(vnet) \
-	INIT_FROM_VNET(vnet, VNET_MOD_NET, struct vnet_net, vnet_net)
-
-#define	VNET_NET(sym)	VSYM(vnet_net, sym)
-
-#define	V_ether_ipfw		VNET_NET(ether_ipfw)
-#define	V_if_index		VNET_NET(if_index)
-#define	V_if_indexlim		VNET_NET(if_indexlim)
-#define	V_if_cloners		VNET_NET(if_cloners)
-#define	V_if_cloners_count	VNET_NET(if_cloners_count)
-#define	V_ifg_head		VNET_NET(ifg_head)
-#define	V_ifindex_table		VNET_NET(ifindex_table)
-#define	V_ifklist		VNET_NET(ifklist)
-#define	V_ifnet			VNET_NET(ifnet)
-#define	V_lo_cloner		VNET_NET(lo_cloner)
-#define	V_lo_cloner_data	VNET_NET(lo_cloner_data)
-#define	V_loif			VNET_NET(loif)
-#define	V_rawcb_list		VNET_NET(rawcb_list)
+#define	VNET_VNET_PTR(vnet, n)		(&(n))
+#define	VNET_VNET_GET(vnet, n)		(n)
+#define	VNET_VNET_SET(vnet, n, v)	((n) = (v))
+
+#define	VNET_PTR(n)		(&(n))
+#define	VNET_GET(n)		(n)
+#define	VNET_SET(n, v)		((n) = (v))
+
+#endif /* VIMAGE */
+
+#endif /* _KERNEL */
 
 #endif /* !_NET_VNET_H_ */