diff --git a/sys/amd64/amd64/elf_machdep.c b/sys/amd64/amd64/elf_machdep.c
index ec1afc7d9245..4f6d178eb35a 100644
--- a/sys/amd64/amd64/elf_machdep.c
+++ b/sys/amd64/amd64/elf_machdep.c
@@ -72,7 +72,8 @@ struct sysentvec elf64_freebsd_sysvec = {
 	.sv_copyout_strings	= exec_copyout_strings,
 	.sv_setregs	= exec_setregs,
 	.sv_fixlimit	= NULL,
-	.sv_maxssiz	= NULL
+	.sv_maxssiz	= NULL,
+	.sv_flags	= SV_ABI_FREEBSD | SV_LP64
 };
 
 static Elf64_Brandinfo freebsd_brand_info = {
diff --git a/sys/amd64/linux32/linux32_sysvec.c b/sys/amd64/linux32/linux32_sysvec.c
index e2337007ef5d..3acee30ca6b1 100644
--- a/sys/amd64/linux32/linux32_sysvec.c
+++ b/sys/amd64/linux32/linux32_sysvec.c
@@ -1026,6 +1026,7 @@ struct sysentvec elf_linux_sysvec = {
 	.sv_setregs	= exec_linux_setregs,
 	.sv_fixlimit	= linux32_fixlimit,
 	.sv_maxssiz	= &linux32_maxssiz,
+	.sv_flags	= SV_ABI_LINUX | SV_ILP32 | SV_IA32
 };
 
 static Elf32_Brandinfo linux_brand = {
diff --git a/sys/arm/arm/elf_machdep.c b/sys/arm/arm/elf_machdep.c
index f44a622935bc..693eab117148 100644
--- a/sys/arm/arm/elf_machdep.c
+++ b/sys/arm/arm/elf_machdep.c
@@ -72,7 +72,8 @@ struct sysentvec elf32_freebsd_sysvec = {
 	.sv_copyout_strings = exec_copyout_strings,
 	.sv_setregs	= exec_setregs,
 	.sv_fixlimit	= NULL,
-	.sv_maxssiz	= NULL
+	.sv_maxssiz	= NULL,
+	.sv_flags	= SV_ABI_FREEBSD | SV_ILP32
 };
 
 static Elf32_Brandinfo freebsd_brand_info = {
diff --git a/sys/compat/ia32/ia32_sysvec.c b/sys/compat/ia32/ia32_sysvec.c
index ef74ba0e075d..0b32b9a2e19c 100644
--- a/sys/compat/ia32/ia32_sysvec.c
+++ b/sys/compat/ia32/ia32_sysvec.c
@@ -135,7 +135,8 @@ struct sysentvec ia32_freebsd_sysvec = {
 	.sv_copyout_strings	= ia32_copyout_strings,
 	.sv_setregs	= ia32_setregs,
 	.sv_fixlimit	= ia32_fixlimit,
-	.sv_maxssiz	= &ia32_maxssiz
+	.sv_maxssiz	= &ia32_maxssiz,
+	.sv_flags	= SV_ABI_FREEBSD | SV_IA32 | SV_ILP32
 };
 
 
diff --git a/sys/compat/svr4/svr4_sysvec.c b/sys/compat/svr4/svr4_sysvec.c
index 60cca7bc5f5e..63e8e5499978 100644
--- a/sys/compat/svr4/svr4_sysvec.c
+++ b/sys/compat/svr4/svr4_sysvec.c
@@ -190,7 +190,8 @@ struct sysentvec svr4_sysvec = {
 	.sv_copyout_strings = exec_copyout_strings,
 	.sv_setregs	= exec_setregs,
 	.sv_fixlimit	= NULL,
-	.sv_maxssiz     = NULL
+	.sv_maxssiz     = NULL,
+	.sv_flags	= SV_ABI_UNDEF | SV_IA32 | SV_ILP32
 };
 
 const char      svr4_emul_path[] = "/compat/svr4";
diff --git a/sys/i386/i386/elf_machdep.c b/sys/i386/i386/elf_machdep.c
index 93f1d4522fbf..19eddd09b49b 100644
--- a/sys/i386/i386/elf_machdep.c
+++ b/sys/i386/i386/elf_machdep.c
@@ -72,7 +72,8 @@ struct sysentvec elf32_freebsd_sysvec = {
 	.sv_copyout_strings	= exec_copyout_strings,
 	.sv_setregs	= exec_setregs,
 	.sv_fixlimit	= NULL,
-	.sv_maxssiz	= NULL
+	.sv_maxssiz	= NULL,
+	.sv_flags	= SV_ABI_FREEBSD | SV_IA32 | SV_ILP32
 };
 
 static Elf32_Brandinfo freebsd_brand_info = {
diff --git a/sys/i386/ibcs2/ibcs2_sysvec.c b/sys/i386/ibcs2/ibcs2_sysvec.c
index 2c834dd509a2..9112ed77f0d1 100644
--- a/sys/i386/ibcs2/ibcs2_sysvec.c
+++ b/sys/i386/ibcs2/ibcs2_sysvec.c
@@ -85,7 +85,8 @@ struct sysentvec ibcs2_svr3_sysvec = {
 	.sv_copyout_strings = exec_copyout_strings,
 	.sv_setregs	= exec_setregs,
 	.sv_fixlimit	= NULL,
-	.sv_maxssiz	= NULL
+	.sv_maxssiz	= NULL,
+	.sv_flags	= SV_ABI_UNDEF | SV_IA32 | SV_ILP32
 };
 
 static int
diff --git a/sys/i386/linux/linux_sysvec.c b/sys/i386/linux/linux_sysvec.c
index a3acfc9fe6b4..7444901267e7 100644
--- a/sys/i386/linux/linux_sysvec.c
+++ b/sys/i386/linux/linux_sysvec.c
@@ -837,7 +837,8 @@ struct sysentvec linux_sysvec = {
 	.sv_copyout_strings = exec_copyout_strings,
 	.sv_setregs	= exec_linux_setregs,
 	.sv_fixlimit	= NULL,
-	.sv_maxssiz	= NULL
+	.sv_maxssiz	= NULL,
+	.sv_flags	= SV_ABI_LINUX | SV_AOUT | SV_IA32 | SV_ILP32
 };
 
 struct sysentvec elf_linux_sysvec = {
@@ -867,7 +868,8 @@ struct sysentvec elf_linux_sysvec = {
 	.sv_copyout_strings = exec_copyout_strings,
 	.sv_setregs	= exec_linux_setregs,
 	.sv_fixlimit	= NULL,
-	.sv_maxssiz	= NULL
+	.sv_maxssiz	= NULL,
+	.sv_flags	= SV_ABI_LINUX | SV_IA32 | SV_ILP32
 };
 
 static Elf32_Brandinfo linux_brand = {
diff --git a/sys/ia64/ia64/elf_machdep.c b/sys/ia64/ia64/elf_machdep.c
index 94f4cdc1796d..a3a6e57f8510 100644
--- a/sys/ia64/ia64/elf_machdep.c
+++ b/sys/ia64/ia64/elf_machdep.c
@@ -80,7 +80,8 @@ struct sysentvec elf64_freebsd_sysvec = {
 	.sv_copyout_strings = exec_copyout_strings,
 	.sv_setregs	= exec_setregs,
 	.sv_fixlimit	= NULL,
-	.sv_maxssiz	= NULL
+	.sv_maxssiz	= NULL,
+	.sv_flags	= SV_ABI_FREEBSD | SV_LP64
 };
 
 static Elf64_Brandinfo freebsd_brand_info = {
diff --git a/sys/kern/imgact_aout.c b/sys/kern/imgact_aout.c
index f4e4614f3699..6c2f62752713 100644
--- a/sys/kern/imgact_aout.c
+++ b/sys/kern/imgact_aout.c
@@ -82,7 +82,13 @@ struct sysentvec aout_sysvec = {
 	.sv_copyout_strings	= exec_copyout_strings,
 	.sv_setregs	= exec_setregs,
 	.sv_fixlimit	= NULL,
-	.sv_maxssiz	= NULL
+	.sv_maxssiz	= NULL,
+	.sv_flags	= SV_ABI_FREEBSD | SV_AOUT |
+#if defined(__i386__)
+	SV_IA32 | SV_ILP32
+#else
+#error Choose SV_XXX flags for the platform
+#endif
 };
 
 static int
diff --git a/sys/kern/kern_thr.c b/sys/kern/kern_thr.c
index dade1c23c380..3802259c047f 100644
--- a/sys/kern/kern_thr.c
+++ b/sys/kern/kern_thr.c
@@ -57,14 +57,12 @@ __FBSDID("$FreeBSD$");
 
 #ifdef COMPAT_IA32
 
-extern struct sysentvec ia32_freebsd_sysvec;
-
 static inline int
 suword_lwpid(void *addr, lwpid_t lwpid)
 {
 	int error;
 
-	if (curproc->p_sysent != &ia32_freebsd_sysvec)
+	if (SV_CURPROC_FLAG(SV_LP64))
 		error = suword(addr, lwpid);
 	else
 		error = suword32(addr, lwpid);
diff --git a/sys/kern/uipc_socket.c b/sys/kern/uipc_socket.c
index e71250342ea1..53c800e2ae26 100644
--- a/sys/kern/uipc_socket.c
+++ b/sys/kern/uipc_socket.c
@@ -136,9 +136,8 @@ __FBSDID("$FreeBSD$");
 
 #ifdef COMPAT_IA32
 #include <sys/mount.h>
+#include <sys/sysent.h>
 #include <compat/freebsd32/freebsd32.h>
-
-extern struct sysentvec ia32_freebsd_sysvec;
 #endif
 
 static int	soreceive_rcvoob(struct socket *so, struct uio *uio,
@@ -2280,7 +2279,7 @@ sosetopt(struct socket *so, struct sockopt *sopt)
 		case SO_SNDTIMEO:
 		case SO_RCVTIMEO:
 #ifdef COMPAT_IA32
-			if (curthread->td_proc->p_sysent == &ia32_freebsd_sysvec) {
+			if (SV_CURPROC_FLAG(SV_ILP32)) {
 				struct timeval32 tv32;
 
 				error = sooptcopyin(sopt, &tv32, sizeof tv32,
@@ -2461,7 +2460,7 @@ sogetopt(struct socket *so, struct sockopt *sopt)
 			tv.tv_sec = optval / hz;
 			tv.tv_usec = (optval % hz) * tick;
 #ifdef COMPAT_IA32
-			if (curthread->td_proc->p_sysent == &ia32_freebsd_sysvec) {
+			if (SV_CURPROC_FLAG(SV_ILP32)) {
 				struct timeval32 tv32;
 
 				CP(tv, tv32, tv_sec);
diff --git a/sys/mips/mips/elf_machdep.c b/sys/mips/mips/elf_machdep.c
index 023472211520..dc08bc266f07 100644
--- a/sys/mips/mips/elf_machdep.c
+++ b/sys/mips/mips/elf_machdep.c
@@ -74,7 +74,8 @@ struct sysentvec elf32_freebsd_sysvec = {
 	.sv_copyout_strings = exec_copyout_strings,
 	.sv_setregs	= exec_setregs,
 	.sv_fixlimit	= NULL,
-	.sv_maxssiz	= NULL
+	.sv_maxssiz	= NULL,
+	.sv_flags	= SV_ABI_FREEBSD | SV_ILP32
 };
 
 static Elf32_Brandinfo freebsd_brand_info = {
diff --git a/sys/powerpc/powerpc/elf_machdep.c b/sys/powerpc/powerpc/elf_machdep.c
index dadf3ca16ceb..69ac55b4843a 100644
--- a/sys/powerpc/powerpc/elf_machdep.c
+++ b/sys/powerpc/powerpc/elf_machdep.c
@@ -75,7 +75,8 @@ struct sysentvec elf32_freebsd_sysvec = {
 	.sv_copyout_strings = exec_copyout_strings,
 	.sv_setregs	= exec_setregs,
 	.sv_fixlimit	= NULL,
-	.sv_maxssiz	= NULL
+	.sv_maxssiz	= NULL,
+	.sv_flags	= SV_ABI_FREEBSD | SV_ILP32
 };
 
 static Elf32_Brandinfo freebsd_brand_info = {
diff --git a/sys/sparc64/sparc64/elf_machdep.c b/sys/sparc64/sparc64/elf_machdep.c
index d1e610a739b6..a956c5cc9842 100644
--- a/sys/sparc64/sparc64/elf_machdep.c
+++ b/sys/sparc64/sparc64/elf_machdep.c
@@ -87,7 +87,8 @@ static struct sysentvec elf64_freebsd_sysvec = {
 	.sv_copyout_strings = exec_copyout_strings,
 	.sv_setregs	= exec_setregs,
 	.sv_fixlimit	= NULL,
-	.sv_maxssiz	= NULL
+	.sv_maxssiz	= NULL,
+	.sv_flags	= SV_ABI_FREEBSD | SV_LP64
 };
 
 static Elf64_Brandinfo freebsd_brand_info = {
diff --git a/sys/sys/sysent.h b/sys/sys/sysent.h
index 0ec07a7e65bb..c0689462227d 100644
--- a/sys/sys/sysent.h
+++ b/sys/sys/sysent.h
@@ -100,8 +100,22 @@ struct sysentvec {
 	void		(*sv_setregs)(struct thread *, u_long, u_long, u_long);
 	void		(*sv_fixlimit)(struct rlimit *, int);
 	u_long		*sv_maxssiz;
+	u_int		sv_flags;
 };
 
+#define	SV_ILP32	0x000100
+#define	SV_LP64		0x000200
+#define	SV_IA32		0x004000
+#define	SV_AOUT		0x008000
+
+#define	SV_ABI_MASK	0xff
+#define	SV_CURPROC_FLAG(x) (curproc->p_sysent->sv_flags & (x))
+#define	SV_CURPROC_ABI() (curproc->p_sysent->sv_flags & SV_ABI_MASK)
+/* same as ELFOSABI_XXX, to prevent header pollution */
+#define	SV_ABI_LINUX	3
+#define	SV_ABI_FREEBSD 	9
+#define	SV_ABI_UNDEF	255
+
 #ifdef _KERNEL
 extern struct sysentvec aout_sysvec;
 extern struct sysentvec elf_freebsd_sysvec;