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, 8 insertions, 15 deletions

diff --git a/sys/net/if_clone.c b/sys/net/if_clone.c
index eaa7397..9347d2c 100644
--- a/sys/net/if_clone.c
+++ b/sys/net/if_clone.c
@@ -58,10 +58,11 @@ static int	if_clone_createif(struct if_clone *ifc, char *name, size_t len,
 static int	vnet_clone_iattach(const void *);
 
 static struct mtx	if_cloners_mtx;
-#ifdef VIMAGE_GLOBALS
-static int		if_cloners_count;
-LIST_HEAD(, if_clone)	if_cloners;
-#endif
+static VNET_DEFINE(int, if_cloners_count);
+VNET_DEFINE(LIST_HEAD(, if_clone), if_cloners);
+
+#define	V_if_cloners_count	VNET_GET(if_cloners_count)
+#define	V_if_cloners		VNET_GET(if_cloners)
 
 #define IF_CLONERS_LOCK_INIT()		\
     mtx_init(&if_cloners_mtx, "if_cloners lock", NULL, MTX_DEF)
@@ -115,17 +116,16 @@ LIST_HEAD(, if_clone)	if_cloners;
 
 static MALLOC_DEFINE(M_CLONE, "clone", "interface cloning framework");
 
-#ifndef VIMAGE_GLOBALS
+#ifdef VIMAGE
 static const vnet_modinfo_t vnet_clone_modinfo = {
 	.vmi_id		= VNET_MOD_IF_CLONE,
 	.vmi_name	= "if_clone",
 	.vmi_iattach	= vnet_clone_iattach
 };
-#endif /* !VIMAGE_GLOBALS */
+#endif
 
 static int vnet_clone_iattach(const void *unused __unused)
 {
-	INIT_VNET_NET(curvnet);
 
 	LIST_INIT(&V_if_cloners);
 	return (0);
@@ -136,7 +136,7 @@ if_clone_init(void)
 {
 
 	IF_CLONERS_LOCK_INIT();
-#ifndef VIMAGE_GLOBALS
+#ifdef VIMAGE
 	vnet_mod_register(&vnet_clone_modinfo);
 #else
 	vnet_clone_iattach(NULL);
@@ -149,7 +149,6 @@ if_clone_init(void)
 int
 if_clone_create(char *name, size_t len, caddr_t params)
 {
-	INIT_VNET_NET(curvnet);
 	struct if_clone *ifc;
 
 	/* Try to find an applicable cloner for this request */
@@ -162,7 +161,6 @@ if_clone_create(char *name, size_t len, caddr_t params)
 #ifdef VIMAGE
 	if (ifc == NULL && !IS_DEFAULT_VNET(curvnet)) {
 		CURVNET_SET_QUIET(vnet0);
-		INIT_VNET_NET(vnet0);
 		LIST_FOREACH(ifc, &V_if_cloners, ifc_list) {
 			if (ifc->ifc_match(ifc, name))
 				break;
@@ -213,7 +211,6 @@ if_clone_createif(struct if_clone *ifc, char *name, size_t len, caddr_t params)
 int
 if_clone_destroy(const char *name)
 {
-	INIT_VNET_NET(curvnet);
 	struct if_clone *ifc;
 	struct ifnet *ifp;
 
@@ -231,7 +228,6 @@ if_clone_destroy(const char *name)
 #ifdef VIMAGE
 	if (ifc == NULL && !IS_DEFAULT_VNET(curvnet)) {
 		CURVNET_SET_QUIET(vnet0);
-		INIT_VNET_NET(vnet0);
 		LIST_FOREACH(ifc, &V_if_cloners, ifc_list) {
 			if (ifc->ifc_match(ifc, name))
 				break;
@@ -289,7 +285,6 @@ if_clone_destroyif(struct if_clone *ifc, struct ifnet *ifp)
 void
 if_clone_attach(struct if_clone *ifc)
 {
-	INIT_VNET_NET(curvnet);
 	int len, maxclone;
 
 	/*
@@ -322,7 +317,6 @@ if_clone_attach(struct if_clone *ifc)
 void
 if_clone_detach(struct if_clone *ifc)
 {
-	INIT_VNET_NET(curvnet);
 	struct ifc_simple_data *ifcs = ifc->ifc_data;
 
 	IF_CLONERS_LOCK();
@@ -362,7 +356,6 @@ if_clone_free(struct if_clone *ifc)
 int
 if_clone_list(struct if_clonereq *ifcr)
 {
-	INIT_VNET_NET(curvnet);
 	char *buf, *dst, *outbuf = NULL;
 	struct if_clone *ifc;
 	int buf_count, count, err = 0;