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, 5 insertions, 12 deletions

diff --git a/sys/netinet6/scope6.c b/sys/netinet6/scope6.c
index c9028b9..a4093b1 100644
--- a/sys/netinet6/scope6.c
+++ b/sys/netinet6/scope6.c
@@ -48,8 +48,8 @@ __FBSDID("$FreeBSD$");
 
 #include <netinet/ip6.h>
 #include <netinet6/in6_var.h>
+#include <netinet6/ip6_var.h>
 #include <netinet6/scope6_var.h>
-#include <netinet6/vinet6.h>
 
 
 /*
@@ -62,10 +62,10 @@ static struct mtx scope6_lock;
 #define	SCOPE6_UNLOCK()		mtx_unlock(&scope6_lock)
 #define	SCOPE6_LOCK_ASSERT()	mtx_assert(&scope6_lock, MA_OWNED)
 
-#ifdef VIMAGE_GLOBALS
-static struct scope6_id sid_default;
-int ip6_use_defzone;
-#endif
+static VNET_DEFINE(struct scope6_id, sid_default);
+VNET_DEFINE(int, ip6_use_defzone);
+
+#define	V_sid_default			VNET_GET(sid_default)
 
 #define SID(ifp) \
 	(((struct in6_ifextra *)(ifp)->if_afdata[AF_INET6])->scope6_id)
@@ -73,7 +73,6 @@ int ip6_use_defzone;
 void
 scope6_init(void)
 {
-	INIT_VNET_INET6(curvnet);
 
 #ifdef ENABLE_DEFAULT_SCOPE
 	V_ip6_use_defzone = 1;
@@ -121,7 +120,6 @@ scope6_ifdetach(struct scope6_id *sid)
 int
 scope6_set(struct ifnet *ifp, struct scope6_id *idlist)
 {
-	INIT_VNET_NET(ifp->if_vnet);
 	int i;
 	int error = 0;
 	struct scope6_id *sid = NULL;
@@ -276,7 +274,6 @@ in6_addrscope(struct in6_addr *addr)
 void
 scope6_setdefault(struct ifnet *ifp)
 {
-	INIT_VNET_INET6(ifp->if_vnet);
 
 	/*
 	 * Currently, this function just sets the default "interfaces"
@@ -300,7 +297,6 @@ scope6_setdefault(struct ifnet *ifp)
 int
 scope6_get_default(struct scope6_id *idlist)
 {
-	INIT_VNET_INET6(curvnet);
 
 	SCOPE6_LOCK();
 	*idlist = V_sid_default;
@@ -312,7 +308,6 @@ scope6_get_default(struct scope6_id *idlist)
 u_int32_t
 scope6_addr2default(struct in6_addr *addr)
 {
-	INIT_VNET_INET6(curvnet);
 	u_int32_t id;
 
 	/*
@@ -343,7 +338,6 @@ scope6_addr2default(struct in6_addr *addr)
 int
 sa6_embedscope(struct sockaddr_in6 *sin6, int defaultok)
 {
-	INIT_VNET_NET(curvnet);
 	struct ifnet *ifp;
 	u_int32_t zoneid;
 
@@ -380,7 +374,6 @@ sa6_embedscope(struct sockaddr_in6 *sin6, int defaultok)
 int
 sa6_recoverscope(struct sockaddr_in6 *sin6)
 {
-	INIT_VNET_NET(curvnet);
 	char ip6buf[INET6_ADDRSTRLEN];
 	u_int32_t zoneid;