diff --git a/sys/amd64/amd64/exec_machdep.c b/sys/amd64/amd64/exec_machdep.c
--- a/sys/amd64/amd64/exec_machdep.c
+++ b/sys/amd64/amd64/exec_machdep.c
@@ -77,6 +77,7 @@
 #include <vm/vm_param.h>
 #include <vm/vm_extern.h>
 #include <vm/pmap.h>
+#include <vm/vm_map.h>
 
 #ifdef DDB
 #ifndef KDB
diff --git a/sys/amd64/linux/linux_sysvec.c b/sys/amd64/linux/linux_sysvec.c
--- a/sys/amd64/linux/linux_sysvec.c
+++ b/sys/amd64/linux/linux_sysvec.c
@@ -772,7 +772,7 @@
 
 	tkoff = kern_timekeep_base - linux_vdso_base;
 	ktimekeep_base = (l_uintptr_t *)(linux_vdso_mapping + tkoff);
-	*ktimekeep_base = sv->sv_timekeep_base;
+	*ktimekeep_base = sv->sv_shared_page_base + sv->sv_timekeep_offset;
 
 	tkoff = kern_tsc_selector - linux_vdso_base;
 	ktsc_selector = (l_uintptr_t *)(linux_vdso_mapping + tkoff);
diff --git a/sys/amd64/linux32/linux32_sysvec.c b/sys/amd64/linux32/linux32_sysvec.c
--- a/sys/amd64/linux32/linux32_sysvec.c
+++ b/sys/amd64/linux32/linux32_sysvec.c
@@ -924,7 +924,7 @@
 
 	tkoff = kern_timekeep_base - linux_vdso_base;
 	ktimekeep_base = (l_uintptr_t *)(linux_vdso_mapping + tkoff);
-	*ktimekeep_base = sv->sv_timekeep_base;
+	*ktimekeep_base = sv->sv_shared_page_base + sv->sv_timekeep_offset;
 
 	tkoff = kern_tsc_selector - linux_vdso_base;
 	ktsc_selector = (l_uintptr_t *)(linux_vdso_mapping + tkoff);
diff --git a/sys/arm/arm/exec_machdep.c b/sys/arm/arm/exec_machdep.c
--- a/sys/arm/arm/exec_machdep.c
+++ b/sys/arm/arm/exec_machdep.c
@@ -346,7 +346,7 @@
 	tf->tf_pc = (register_t)catcher;
 	tf->tf_usr_sp = (register_t)fp;
 	sysent = p->p_sysent;
-	if (sysent->sv_sigcode_base != 0)
+	if (PROC_HAS_SHP(p))
 		tf->tf_usr_lr = (register_t)PROC_SIGCODE(p);
 	else
 		tf->tf_usr_lr = (register_t)(PROC_PS_STRINGS(p) -
diff --git a/sys/arm64/arm64/exec_machdep.c b/sys/arm64/arm64/exec_machdep.c
--- a/sys/arm64/arm64/exec_machdep.c
+++ b/sys/arm64/arm64/exec_machdep.c
@@ -50,6 +50,8 @@
 
 #include <vm/vm.h>
 #include <vm/vm_param.h>
+#include <vm/pmap.h>
+#include <vm/vm_map.h>
 
 #include <machine/armreg.h>
 #include <machine/kdb.h>
diff --git a/sys/arm64/arm64/freebsd32_machdep.c b/sys/arm64/arm64/freebsd32_machdep.c
--- a/sys/arm64/arm64/freebsd32_machdep.c
+++ b/sys/arm64/arm64/freebsd32_machdep.c
@@ -418,7 +418,7 @@
 	tf->tf_elr = (register_t)catcher;
 	tf->tf_x[13] = (register_t)fp;
 	sysent = p->p_sysent;
-	if (sysent->sv_sigcode_base != 0)
+	if (PROC_HAS_SHP(p))
 		tf->tf_x[14] = (register_t)PROC_SIGCODE(p);
 	else
 		tf->tf_x[14] = (register_t)(PROC_PS_STRINGS(p) -
diff --git a/sys/arm64/linux/linux_sysvec.c b/sys/arm64/linux/linux_sysvec.c
--- a/sys/arm64/linux/linux_sysvec.c
+++ b/sys/arm64/linux/linux_sysvec.c
@@ -619,7 +619,7 @@
 
 	tkoff = kern_timekeep_base - linux_vdso_base;
 	ktimekeep_base = (l_uintptr_t *)(linux_vdso_mapping + tkoff);
-	*ktimekeep_base = sv->sv_timekeep_base;
+	*ktimekeep_base = sv->sv_shared_page_base + sv->sv_timekeep_offset;
 }
 SYSINIT(elf_linux_exec_sysvec_init, SI_SUB_EXEC + 1, SI_ORDER_ANY,
     linux_exec_sysvec_init, &elf_linux_sysvec);
diff --git a/sys/compat/freebsd32/freebsd32_misc.c b/sys/compat/freebsd32/freebsd32_misc.c
--- a/sys/compat/freebsd32/freebsd32_misc.c
+++ b/sys/compat/freebsd32/freebsd32_misc.c
@@ -3525,7 +3525,7 @@
 	/*
 	 * Install sigcode.
 	 */
-	if (sysent->sv_sigcode_base == 0) {
+	if (!PROC_HAS_SHP(imgp->proc)) {
 		szsigcode = *sysent->sv_szsigcode;
 		destp -= szsigcode;
 		destp = rounddown2(destp, sizeof(uint32_t));
diff --git a/sys/i386/i386/exec_machdep.c b/sys/i386/i386/exec_machdep.c
--- a/sys/i386/i386/exec_machdep.c
+++ b/sys/i386/i386/exec_machdep.c
@@ -237,7 +237,7 @@
 	}
 
 	regs->tf_esp = (int)fp;
-	if (p->p_sysent->sv_sigcode_base != 0) {
+	if (PROC_HAS_SHP(p)) {
 		regs->tf_eip = PROC_SIGCODE(p) + szsigcode -
 		    szosigcode;
 	} else {
diff --git a/sys/i386/linux/linux_sysvec.c b/sys/i386/linux/linux_sysvec.c
--- a/sys/i386/linux/linux_sysvec.c
+++ b/sys/i386/linux/linux_sysvec.c
@@ -866,7 +866,7 @@
 
 	tkoff = kern_timekeep_base - linux_vdso_base;
 	ktimekeep_base = (l_uintptr_t *)(linux_vdso_mapping + tkoff);
-	*ktimekeep_base = sv->sv_timekeep_base;
+	*ktimekeep_base = sv->sv_shared_page_base + sv->sv_timekeep_offset;
 
 	tkoff = kern_tsc_selector - linux_vdso_base;
 	ktsc_selector = (l_uintptr_t *)(linux_vdso_mapping + tkoff);
diff --git a/sys/kern/imgact_elf.c b/sys/kern/imgact_elf.c
--- a/sys/kern/imgact_elf.c
+++ b/sys/kern/imgact_elf.c
@@ -1433,11 +1433,14 @@
 {
 	Elf_Auxargs *args = (Elf_Auxargs *)imgp->auxargs;
 	Elf_Auxinfo *argarray, *pos;
+	struct vmspace *vmspace;
 	int error;
 
 	argarray = pos = malloc(AT_COUNT * sizeof(*pos), M_TEMP,
 	    M_WAITOK | M_ZERO);
 
+	vmspace = imgp->proc->p_vmspace;
+
 	if (args->execfd != -1)
 		AUXARGS_ENTRY(pos, AT_EXECFD, args->execfd);
 	AUXARGS_ENTRY(pos, AT_PHDR, args->phdr);
@@ -1461,9 +1464,9 @@
 		AUXARGS_ENTRY_PTR(pos, AT_PAGESIZES, imgp->pagesizes);
 		AUXARGS_ENTRY(pos, AT_PAGESIZESLEN, imgp->pagesizeslen);
 	}
-	if (imgp->sysent->sv_timekeep_base != 0) {
+	if ((imgp->sysent->sv_flags & SV_TIMEKEEP) != 0) {
 		AUXARGS_ENTRY(pos, AT_TIMEKEEP,
-		    imgp->sysent->sv_timekeep_base);
+		    vmspace->vm_shp_base + imgp->sysent->sv_timekeep_offset);
 	}
 	AUXARGS_ENTRY(pos, AT_STACKPROT, imgp->sysent->sv_shared_page_obj
 	    != NULL && imgp->stack_prot != 0 ? imgp->stack_prot :
@@ -1479,10 +1482,16 @@
 	AUXARGS_ENTRY(pos, AT_ENVC, imgp->args->envc);
 	AUXARGS_ENTRY_PTR(pos, AT_ENVV, imgp->envv);
 	AUXARGS_ENTRY_PTR(pos, AT_PS_STRINGS, imgp->ps_strings);
-	if (imgp->sysent->sv_fxrng_gen_base != 0)
-		AUXARGS_ENTRY(pos, AT_FXRNG, imgp->sysent->sv_fxrng_gen_base);
-	if (imgp->sysent->sv_vdso_base != 0 && __elfN(vdso) != 0)
-		AUXARGS_ENTRY(pos, AT_KPRELOAD, imgp->sysent->sv_vdso_base);
+#ifdef RANDOM_FENESTRASX
+	if ((imgp->sysent->sv_flags & SV_RNG_SEED_VER) != 0) {
+		AUXARGS_ENTRY(pos, AT_FXRNG,
+		    vmspace->vm_shp_base + imgp->sysent->sv_fxrng_gen_offset);
+	}
+#endif
+	if ((imgp->sysent->sv_flags & SV_DSO_SIG) != 0 && __elfN(vdso) != 0) {
+		AUXARGS_ENTRY(pos, AT_KPRELOAD,
+		    vmspace->vm_shp_base + imgp->sysent->sv_vdso_offset);
+	}
 	AUXARGS_ENTRY(pos, AT_NULL, 0);
 
 	free(imgp->auxargs, M_TEMP);
diff --git a/sys/kern/kern_exec.c b/sys/kern/kern_exec.c
--- a/sys/kern/kern_exec.c
+++ b/sys/kern/kern_exec.c
@@ -1106,18 +1106,16 @@
 exec_free_abi_mappings(struct proc *p)
 {
 	struct vmspace *vmspace;
-	struct sysentvec *sv;
 
 	vmspace = p->p_vmspace;
 	if (refcount_load(&vmspace->vm_refcnt) != 1)
 		return;
 
-	sv = p->p_sysent;
-	if (sv->sv_shared_page_obj == NULL)
+	if (!PROC_HAS_SHP(p))
 		return;
 
-	pmap_remove(vmspace_pmap(vmspace), sv->sv_shared_page_base,
-	    sv->sv_shared_page_base + sv->sv_shared_page_len);
+	pmap_remove(vmspace_pmap(vmspace), vmspace->vm_shp_base,
+	    vmspace->vm_shp_base + p->p_sysent->sv_shared_page_len);
 }
 
 /*
@@ -1192,6 +1190,7 @@
 			vm_object_deallocate(obj);
 			return (vm_mmap_to_errno(error));
 		}
+		vmspace->vm_shp_base = sv->sv_shared_page_base;
 	}
 
 	return (sv->sv_onexec != NULL ? sv->sv_onexec(p, imgp) : 0);
@@ -1633,7 +1632,7 @@
 	/*
 	 * Install sigcode.
 	 */
-	if (sysent->sv_sigcode_base == 0 && sysent->sv_szsigcode != NULL) {
+	if (sysent->sv_shared_page_base == 0 && sysent->sv_szsigcode != NULL) {
 		szsigcode = *(sysent->sv_szsigcode);
 		destp -= szsigcode;
 		destp = rounddown2(destp, sizeof(void *));
diff --git a/sys/kern/kern_proc.c b/sys/kern/kern_proc.c
--- a/sys/kern/kern_proc.c
+++ b/sys/kern/kern_proc.c
@@ -3096,7 +3096,7 @@
 	if ((req->flags & SCTL_MASK32) != 0) {
 		bzero(&kst32, sizeof(kst32));
 		if (SV_PROC_FLAG(p, SV_ILP32)) {
-			if (sv->sv_sigcode_base != 0) {
+			if (PROC_HAS_SHP(p)) {
 				kst32.ksigtramp_start = PROC_SIGCODE(p);
 				kst32.ksigtramp_end = kst32.ksigtramp_start +
 				    ((sv->sv_flags & SV_DSO_SIG) == 0 ?
@@ -3114,7 +3114,7 @@
 	}
 #endif
 	bzero(&kst, sizeof(kst));
-	if (sv->sv_sigcode_base != 0) {
+	if (PROC_HAS_SHP(p)) {
 		kst.ksigtramp_start = (char *)PROC_SIGCODE(p);
 		kst.ksigtramp_end = (char *)kst.ksigtramp_start +
 		    ((sv->sv_flags & SV_DSO_SIG) == 0 ? *sv->sv_szsigcode :
diff --git a/sys/kern/kern_sharedpage.c b/sys/kern/kern_sharedpage.c
--- a/sys/kern/kern_sharedpage.c
+++ b/sys/kern/kern_sharedpage.c
@@ -305,10 +305,6 @@
 exec_sysvec_init(void *param)
 {
 	struct sysentvec *sv;
-	vm_offset_t sb;
-#ifdef RANDOM_FENESTRASX
-	ptrdiff_t base;
-#endif
 	u_int flags;
 	int res;
 
@@ -322,19 +318,18 @@
 	sv->sv_shared_page_obj = shared_page_obj;
 	if ((flags & SV_ABI_MASK) == SV_ABI_FREEBSD) {
 		if ((flags & SV_DSO_SIG) != 0) {
-			sb = sv->sv_shared_page_base;
 			res = shared_page_fill((uintptr_t)sv->sv_szsigcode,
 			    16, sv->sv_sigcode);
 			if (res == -1)
-				panic("copying sigtramp to shared page");
-			sb += res;
-			sv->sv_vdso_base = sb;
-			sb += sv->sv_sigcodeoff;
-			sv->sv_sigcode_base = sb;
+				panic("copying vdso to shared page");
+			sv->sv_vdso_offset = res;
+			sv->sv_sigcode_offset = res + sv->sv_sigcodeoff;
 		} else {
-			sv->sv_sigcode_base = sv->sv_shared_page_base +
-			    shared_page_fill(*(sv->sv_szsigcode), 16,
-			    sv->sv_sigcode);
+			res = shared_page_fill(*(sv->sv_szsigcode),
+			    16, sv->sv_sigcode);
+			if (res == -1)
+				panic("copying sigtramp to shared page");
+			sv->sv_sigcode_offset = res;
 		}
 	}
 	if ((flags & SV_TIMEKEEP) != 0) {
@@ -348,8 +343,7 @@
 				KASSERT(compat32_svtk != NULL,
 				    ("Compat32 not registered"));
 			}
-			sv->sv_timekeep_base = sv->sv_shared_page_base +
-			    compat32_svtk->sv_timekeep_off;
+			sv->sv_timekeep_offset = compat32_svtk->sv_timekeep_off;
 		} else {
 #endif
 			if ((flags & SV_ABI_MASK) == SV_ABI_FREEBSD) {
@@ -360,8 +354,7 @@
 				KASSERT(host_svtk != NULL,
 				    ("Host not registered"));
 			}
-			sv->sv_timekeep_base = sv->sv_shared_page_base +
-			    host_svtk->sv_timekeep_off;
+			sv->sv_timekeep_offset = host_svtk->sv_timekeep_off;
 #ifdef COMPAT_FREEBSD32
 		}
 #endif
@@ -375,8 +368,8 @@
 		 */
 		if (fxrng_shpage_mapping == NULL)
 			alloc_sv_fxrng_generation();
-		base = (char *)fxrng_shpage_mapping - shared_page_mapping;
-		sv->sv_fxrng_gen_base = sv->sv_shared_page_base + base;
+		sv->sv_fxrng_gen_offset =
+		    (char *)fxrng_shpage_mapping - shared_page_mapping;
 	}
 #endif
 }
@@ -392,20 +385,10 @@
 	    (sv->sv_flags & SV_RNG_SEED_VER));
 
 	sv2->sv_shared_page_obj = sv->sv_shared_page_obj;
-	sv2->sv_sigcode_base = sv2->sv_shared_page_base +
-	    (sv->sv_sigcode_base - sv->sv_shared_page_base);
-	if ((sv2->sv_flags & SV_DSO_SIG) != 0) {
-		sv2->sv_vdso_base = sv2->sv_shared_page_base +
-		    (sv->sv_vdso_base - sv->sv_shared_page_base);
-	}
+	sv2->sv_sigcode_offset = sv->sv_sigcode_offset;
+	sv2->sv_vdso_offset = sv->sv_vdso_offset;
 	if ((sv2->sv_flags & SV_ABI_MASK) != SV_ABI_FREEBSD)
 		return;
-	if ((sv2->sv_flags & SV_TIMEKEEP) != 0) {
-		sv2->sv_timekeep_base = sv2->sv_shared_page_base +
-		    (sv->sv_timekeep_base - sv->sv_shared_page_base);
-	}
-	if ((sv2->sv_flags & SV_RNG_SEED_VER) != 0) {
-		sv2->sv_fxrng_gen_base = sv2->sv_shared_page_base +
-		    (sv->sv_fxrng_gen_base - sv->sv_shared_page_base);
-	}
+	sv2->sv_timekeep_offset = sv->sv_timekeep_offset;
+	sv2->sv_fxrng_gen_offset = sv->sv_fxrng_gen_offset;
 }
diff --git a/sys/powerpc/powerpc/elf32_machdep.c b/sys/powerpc/powerpc/elf32_machdep.c
--- a/sys/powerpc/powerpc/elf32_machdep.c
+++ b/sys/powerpc/powerpc/elf32_machdep.c
@@ -52,6 +52,8 @@
 
 #include <vm/vm.h>
 #include <vm/vm_param.h>
+#include <vm/pmap.h>
+#include <vm/vm_map.h>
 
 #include <machine/altivec.h>
 #include <machine/cpu.h>
diff --git a/sys/powerpc/powerpc/elf64_machdep.c b/sys/powerpc/powerpc/elf64_machdep.c
--- a/sys/powerpc/powerpc/elf64_machdep.c
+++ b/sys/powerpc/powerpc/elf64_machdep.c
@@ -49,6 +49,8 @@
 
 #include <vm/vm.h>
 #include <vm/vm_param.h>
+#include <vm/pmap.h>
+#include <vm/vm_map.h>
 
 #include <machine/altivec.h>
 #include <machine/cpu.h>
@@ -216,10 +218,10 @@
 	 * exec_sysvec_init_secondary() assumes secondary sysvecs use
 	 * identical signal code, and skips allocating a second copy.
 	 * Since the ELFv2 trampoline is a strict subset of the ELFv1 code,
-	 * we can work around this by adjusting the base address. This also
+	 * we can work around this by adjusting the offset. This also
 	 * avoids two copies of the trampoline code being allocated!
 	 */
-	elf64_freebsd_sysvec_v2.sv_sigcode_base +=
+	elf64_freebsd_sysvec_v2.sv_sigcode_offset +=
 	    (uintptr_t)sigcode64_elfv2 - (uintptr_t)&sigcode64;
 	elf64_freebsd_sysvec_v2.sv_szsigcode = &szsigcode64_elfv2;
 }
diff --git a/sys/powerpc/powerpc/elf_common.c b/sys/powerpc/powerpc/elf_common.c
--- a/sys/powerpc/powerpc/elf_common.c
+++ b/sys/powerpc/powerpc/elf_common.c
@@ -34,6 +34,7 @@
 {
 	Elf_Auxargs *args;
 	Elf_Auxinfo *argarray, *pos;
+	struct vmspace *vmspace;
 	int error;
 
 	/*
@@ -58,6 +59,8 @@
 	argarray = pos = malloc(AT_OLD_COUNT * sizeof(*pos), M_TEMP,
 	    M_WAITOK | M_ZERO);
 
+	vmspace = imgp->proc->p_vmspace;
+
 	if (args->execfd != -1)
 		AUXARGS_ENTRY(pos, AT_OLD_EXECFD, args->execfd);
 	AUXARGS_ENTRY(pos, AT_OLD_PHDR, args->phdr);
@@ -81,9 +84,9 @@
 		AUXARGS_ENTRY_PTR(pos, AT_OLD_PAGESIZES, imgp->pagesizes);
 		AUXARGS_ENTRY(pos, AT_OLD_PAGESIZESLEN, imgp->pagesizeslen);
 	}
-	if (imgp->sysent->sv_timekeep_base != 0) {
+	if ((imgp->sysent->sv_flags & SV_TIMEKEEP) != 0) {
 		AUXARGS_ENTRY(pos, AT_OLD_TIMEKEEP,
-		    imgp->sysent->sv_timekeep_base);
+		    vmspace->vm_shp_base + imgp->sysent->sv_timekeep_offset);
 	}
 	AUXARGS_ENTRY(pos, AT_OLD_STACKPROT, imgp->sysent->sv_shared_page_obj
 	    != NULL && imgp->stack_prot != 0 ? imgp->stack_prot :
diff --git a/sys/powerpc/powerpc/exec_machdep.c b/sys/powerpc/powerpc/exec_machdep.c
--- a/sys/powerpc/powerpc/exec_machdep.c
+++ b/sys/powerpc/powerpc/exec_machdep.c
@@ -94,7 +94,10 @@
 #include <machine/trap.h>
 #include <machine/vmparam.h>
 
+#include <vm/vm.h>
+#include <vm/vm_param.h>
 #include <vm/pmap.h>
+#include <vm/vm_map.h>
 
 #ifdef FPU_EMU
 #include <powerpc/fpu/fpu_extern.h>
diff --git a/sys/riscv/riscv/exec_machdep.c b/sys/riscv/riscv/exec_machdep.c
--- a/sys/riscv/riscv/exec_machdep.c
+++ b/sys/riscv/riscv/exec_machdep.c
@@ -415,7 +415,7 @@
 	tf->tf_sp = (register_t)fp;
 
 	sysent = p->p_sysent;
-	if (sysent->sv_sigcode_base != 0)
+	if (PROC_HAS_SHP(p))
 		tf->tf_ra = (register_t)PROC_SIGCODE(p);
 	else
 		tf->tf_ra = (register_t)(PROC_PS_STRINGS(p) -
diff --git a/sys/sys/exec.h b/sys/sys/exec.h
--- a/sys/sys/exec.h
+++ b/sys/sys/exec.h
@@ -92,11 +92,13 @@
 
 /*
  * Address of signal trampoline (in user space).
- * This assumes that the sigcode resides in the shared page, which is true
- * in all cases, except for a.out binaries.
+ * This assumes that the sigcode resides in the shared page.
  */
 #define PROC_SIGCODE(p)		\
-	((p)->p_sysent->sv_sigcode_base)
+	((p)->p_vmspace->vm_shp_base + (p)->p_sysent->sv_sigcode_offset)
+
+#define PROC_HAS_SHP(p)		\
+	((p)->p_sysent->sv_shared_page_obj != NULL)
 
 int exec_map_first_page(struct image_params *);        
 void exec_unmap_first_page(struct image_params *);       
diff --git a/sys/sys/sysent.h b/sys/sys/sysent.h
--- a/sys/sys/sysent.h
+++ b/sys/sys/sysent.h
@@ -137,19 +137,19 @@
 	void		(*sv_set_syscall_retval)(struct thread *, int);
 	int		(*sv_fetch_syscall_args)(struct thread *);
 	const char	**sv_syscallnames;
-	vm_offset_t	sv_timekeep_base;
+	vm_offset_t	sv_timekeep_offset;
 	vm_offset_t	sv_shared_page_base;
 	vm_offset_t	sv_shared_page_len;
-	vm_offset_t	sv_sigcode_base;
+	vm_offset_t	sv_sigcode_offset;
 	void		*sv_shared_page_obj;
-	vm_offset_t	sv_vdso_base;
+	vm_offset_t	sv_vdso_offset;
 	void		(*sv_schedtail)(struct thread *);
 	void		(*sv_thread_detach)(struct thread *);
 	int		(*sv_trap)(struct thread *);
 	u_long		*sv_hwcap;	/* Value passed in AT_HWCAP. */
 	u_long		*sv_hwcap2;	/* Value passed in AT_HWCAP2. */
 	const char	*(*sv_machine_arch)(struct proc *);
-	vm_offset_t	sv_fxrng_gen_base;
+	vm_offset_t	sv_fxrng_gen_offset;
 	void		(*sv_onexec_old)(struct thread *td);
 	int		(*sv_onexec)(struct proc *, struct image_params *);
 	void		(*sv_onexit)(struct proc *);
diff --git a/sys/vm/vm_map.h b/sys/vm/vm_map.h
--- a/sys/vm/vm_map.h
+++ b/sys/vm/vm_map.h
@@ -295,6 +295,7 @@
 	caddr_t vm_daddr;	/* (c) user virtual address of data */
 	caddr_t vm_maxsaddr;	/* user VA at max stack growth */
 	vm_offset_t vm_stacktop; /* top of the stack, may not be page-aligned */
+	vm_offset_t vm_shp_base; /* shared page address */
 	u_int vm_refcnt;	/* number of references */
 	/*
 	 * Keep the PMAP last, so that CPU-specific variations of that
diff --git a/sys/vm/vm_map.c b/sys/vm/vm_map.c
--- a/sys/vm/vm_map.c
+++ b/sys/vm/vm_map.c
@@ -4259,6 +4259,7 @@
 	vm2->vm_daddr = vm1->vm_daddr;
 	vm2->vm_maxsaddr = vm1->vm_maxsaddr;
 	vm2->vm_stacktop = vm1->vm_stacktop;
+	vm2->vm_shp_base = vm1->vm_shp_base;
 	vm_map_lock(old_map);
 	if (old_map->busy)
 		vm_map_wait_busy(old_map);