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, 16 insertions, 42 deletions

diff --git a/sys/netgraph/ng_base.c b/sys/netgraph/ng_base.c
index a495701..9eb99d5 100644
--- a/sys/netgraph/ng_base.c
+++ b/sys/netgraph/ng_base.c
@@ -68,6 +68,7 @@
 #include <machine/cpu.h>
 
 #include <net/netisr.h>
+#include <net/vnet.h>
 
 #include <netgraph/ng_message.h>
 #include <netgraph/netgraph.h>
@@ -75,16 +76,9 @@
 
 MODULE_VERSION(netgraph, NG_ABI_VERSION);
 
-#ifndef VIMAGE
-#ifndef VIMAGE_GLOBALS
-struct vnet_netgraph vnet_netgraph_0;
-#endif
-#endif
-
 /* Mutex to protect topology events. */
 static struct mtx	ng_topo_mtx;
 
-static vnet_attach_fn vnet_netgraph_iattach;
 #ifdef VIMAGE
 static vnet_detach_fn vnet_netgraph_idetach;
 #endif
@@ -182,9 +176,9 @@ static struct mtx	ng_typelist_mtx;
 
 /* Hash related definitions */
 /* XXX Don't need to initialise them because it's a LIST */
-#ifdef VIMAGE_GLOBALS
-static LIST_HEAD(, ng_node) ng_ID_hash[NG_ID_HASH_SIZE];
-#endif
+static VNET_DEFINE(LIST_HEAD(, ng_node), ng_ID_hash[NG_ID_HASH_SIZE]);
+#define	V_ng_ID_hash			VNET_GET(ng_ID_hash)
+
 static struct mtx	ng_idhash_mtx;
 /* Method to find a node.. used twice so do it here */
 #define NG_IDHASH_FN(ID) ((ID) % (NG_ID_HASH_SIZE))
@@ -200,9 +194,9 @@ static struct mtx	ng_idhash_mtx;
 		}							\
 	} while (0)
 
-#ifdef VIMAGE_GLOBALS
-static LIST_HEAD(, ng_node) ng_name_hash[NG_NAME_HASH_SIZE];
-#endif
+static VNET_DEFINE(LIST_HEAD(, ng_node), ng_name_hash[NG_NAME_HASH_SIZE]);
+#define	V_ng_name_hash			VNET_GET(ng_name_hash)
+
 static struct mtx	ng_namehash_mtx;
 #define NG_NAMEHASH(NAME, HASH)				\
 	do {						\
@@ -370,9 +364,8 @@ ng_alloc_node(void)
 #define TRAP_ERROR()
 #endif
 
-#ifdef VIMAGE_GLOBALS
-static	ng_ID_t nextID;
-#endif
+static VNET_DEFINE(ng_ID_t, nextID) = 1;
+#define	V_nextID			VNET_GET(nextID)
 
 #ifdef INVARIANTS
 #define CHECK_DATA_MBUF(m)	do {					\
@@ -634,7 +627,6 @@ ng_make_node(const char *typename, node_p *nodepp)
 int
 ng_make_node_common(struct ng_type *type, node_p *nodepp)
 {
-	INIT_VNET_NETGRAPH(curvnet);
 	node_p node;
 
 	/* Require the node type to have been already installed */
@@ -819,7 +811,6 @@ ng_unref_node(node_p node)
 static node_p
 ng_ID2noderef(ng_ID_t ID)
 {
-	INIT_VNET_NETGRAPH(curvnet);
 	node_p node;
 	mtx_lock(&ng_idhash_mtx);
 	NG_IDHASH_FIND(ID, node);
@@ -845,7 +836,6 @@ ng_node2ID(node_p node)
 int
 ng_name_node(node_p node, const char *name)
 {
-	INIT_VNET_NETGRAPH(curvnet);
 	int i, hash;
 	node_p node2;
 
@@ -896,7 +886,6 @@ ng_name_node(node_p node, const char *name)
 node_p
 ng_name2noderef(node_p here, const char *name)
 {
-	INIT_VNET_NETGRAPH(curvnet);
 	node_p node;
 	ng_ID_t temp;
 	int	hash;
@@ -2457,7 +2446,6 @@ ng_apply_item(node_p node, item_p item, int rw)
 static int
 ng_generic_msg(node_p here, item_p item, hook_p lasthook)
 {
-	INIT_VNET_NETGRAPH(curvnet);
 	int error = 0;
 	struct ng_mesg *msg;
 	struct ng_mesg *resp = NULL;
@@ -3080,37 +3068,24 @@ ng_mod_event(module_t mod, int event, void *data)
 	return (error);
 }
 
-#ifndef VIMAGE_GLOBALS
+#ifdef VIMAGE
 static const vnet_modinfo_t vnet_netgraph_modinfo = {
 	.vmi_id		= VNET_MOD_NETGRAPH,
 	.vmi_name	= "netgraph",
-	.vmi_size	= sizeof(struct vnet_netgraph),
 	.vmi_dependson	= VNET_MOD_LOIF,
-	.vmi_iattach	= vnet_netgraph_iattach,
-#ifdef VIMAGE
 	.vmi_idetach	= vnet_netgraph_idetach
-#endif
 };
 #endif
 
-static int
-vnet_netgraph_iattach(const void *unused __unused)
-{
-	INIT_VNET_NETGRAPH(curvnet);
-
-	V_nextID = 1;
-
-	return (0);
-}
-
 #ifdef VIMAGE 
 static int
 vnet_netgraph_idetach(const void *unused __unused)
 {
-	INIT_VNET_NETGRAPH(curvnet);
+#if 0
 	node_p node, last_killed = NULL;
 
-	while ((node = LIST_FIRST(&V_ng_nodelist)) != NULL) {
+	/* XXXRW: utterly bogus. */
+	while ((node = LIST_FIRST(&V_ng_allnodes)) != NULL) {
 		if (node == last_killed) {
 			/* This should never happen */
 			node->nd_flags |= NGF_REALLY_DIE;
@@ -3118,13 +3093,14 @@ vnet_netgraph_idetach(const void *unused __unused)
 			    node->nd_name);
 			ng_rmnode(node, NULL, NULL, 0);
 			/* This must never happen */
-			if (node == LIST_FIRST(&V_ng_nodelist))
+			if (node == LIST_FIRST(&V_ng_allnodes))
 				panic("netgraph node %s won't die",
 				    node->nd_name);
 		}
 		ng_rmnode(node, NULL, NULL, 0);
 		last_killed = node;
 	}
+#endif
 
 	return (0);
 }
@@ -3144,10 +3120,8 @@ ngb_mod_event(module_t mod, int event, void *data)
 	switch (event) {
 	case MOD_LOAD:
 		/* Initialize everything. */
-#ifndef VIMAGE_GLOBALS
+#ifdef VIMAGE
 		vnet_mod_register(&vnet_netgraph_modinfo);
-#else
-		vnet_netgraph_iattach(NULL);
 #endif
 		NG_WORKLIST_LOCK_INIT();
 		mtx_init(&ng_typelist_mtx, "netgraph types mutex", NULL,