diff --git a/sys/amd64/amd64/ptrace_machdep.c b/sys/amd64/amd64/ptrace_machdep.c
--- a/sys/amd64/amd64/ptrace_machdep.c
+++ b/sys/amd64/amd64/ptrace_machdep.c
@@ -63,8 +63,6 @@
 		reg = buf;
 
 		pcb = td->td_pcb;
-		if (td == curthread)
-			update_pcb_bases(pcb);
 		reg->r_fsbase = pcb->pcb_fsbase;
 		reg->r_gsbase = pcb->pcb_gsbase;
 	}
@@ -113,8 +111,6 @@
 		reg = buf;
 
 		pcb = td->td_pcb;
-		if (td == curthread)
-			update_pcb_bases(pcb);
 		reg->r_fsbase = (uint32_t)pcb->pcb_fsbase;
 		reg->r_gsbase = (uint32_t)pcb->pcb_gsbase;
 	}
diff --git a/sys/amd64/amd64/vm_machdep.c b/sys/amd64/amd64/vm_machdep.c
--- a/sys/amd64/amd64/vm_machdep.c
+++ b/sys/amd64/amd64/vm_machdep.c
@@ -693,3 +693,10 @@
 	pcb->pcb_fsbase = (register_t)tls_base;
 	return (0);
 }
+
+void
+cpu_update_pcb(struct thread *td)
+{
+	if (td == curthread)
+		update_pcb_bases(td->td_pcb);
+}
diff --git a/sys/arm/arm/vm_machdep.c b/sys/arm/arm/vm_machdep.c
--- a/sys/arm/arm/vm_machdep.c
+++ b/sys/arm/arm/vm_machdep.c
@@ -290,6 +290,13 @@
 	td->td_pcb->pcb_regs.sf_r5 = (register_t)arg;	/* first arg */
 }
 
+void
+cpu_update_pcb(struct thread *td)
+{
+	if (td == curthread)
+		td->td_pcb->pcb_regs.sf_tpidrurw = (register_t)get_tls();
+}
+
 void
 cpu_exit(struct thread *td)
 {
diff --git a/sys/arm64/arm64/vm_machdep.c b/sys/arm64/arm64/vm_machdep.c
--- a/sys/arm64/arm64/vm_machdep.c
+++ b/sys/arm64/arm64/vm_machdep.c
@@ -300,6 +300,15 @@
 	td->td_pcb->pcb_x[PCB_X20] = (uintptr_t)arg;
 }
 
+void
+cpu_update_pcb(struct thread *td)
+{
+	if (td == curthread) {
+		td->td_pcb->pcb_tpidr_el0 = READ_SPECIALREG(tpidr_el0);
+		td->td_pcb->pcb_tpidrro_el0 = READ_SPECIALREG(tpidrro_el0);
+	}
+}
+
 void
 cpu_exit(struct thread *td)
 {
diff --git a/sys/i386/i386/vm_machdep.c b/sys/i386/i386/vm_machdep.c
--- a/sys/i386/i386/vm_machdep.c
+++ b/sys/i386/i386/vm_machdep.c
@@ -554,6 +554,13 @@
 	return (0);
 }
 
+void
+cpu_update_pcb(struct thread *td)
+{
+	if (td == curthread)
+		td->td_pcb->pcb_gs = rgs();
+}
+
 /*
  * Convert kernel VA to physical address
  */
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
@@ -2415,6 +2415,8 @@
 
 	size = 0;
 
+	cpu_update_pcb(td);
+
 	/* NT_PRSTATUS must be the first register set note. */
 	size += __elfN(register_regset_note)(td, list, &__elfN(regset_prstatus),
 	    target_td);
diff --git a/sys/powerpc/include/reg.h b/sys/powerpc/include/reg.h
--- a/sys/powerpc/include/reg.h
+++ b/sys/powerpc/include/reg.h
@@ -69,11 +69,6 @@
 int	fill_dbregs(struct thread *, struct dbreg *);
 int	set_dbregs(struct thread *, struct dbreg *);
 
-/*
- * MD interfaces.
- */
-void	cpu_save_thread_regs(struct thread *);
-
 #ifdef COMPAT_FREEBSD32
 struct image_params;
 
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
@@ -190,7 +190,6 @@
 	pcb = td->td_pcb;
 
 	if (pcb->pcb_flags & PCB_VEC) {
-		save_vec_nodrop(td);
 		if (dst != NULL) {
 			len += elf32_populate_note(NT_PPC_VMX,
 			    &pcb->pcb_vec, (char *)dst + len,
@@ -201,7 +200,6 @@
 	}
 
 	if (pcb->pcb_flags & PCB_VSX) {
-		save_fpu_nodrop(td);
 		if (dst != NULL) {
 			/*
 			 * Doubleword 0 of VSR0-VSR31 overlap with FPR0-FPR31 and
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
@@ -279,7 +279,6 @@
 	pcb = td->td_pcb;
 
 	if (pcb->pcb_flags & PCB_VEC) {
-		save_vec_nodrop(td);
 		if (dst != NULL) {
 			len += elf64_populate_note(NT_PPC_VMX,
 			    &pcb->pcb_vec, (char *)dst + len,
@@ -290,7 +289,6 @@
 	}
 
 	if (pcb->pcb_flags & PCB_VSX) {
-		save_fpu_nodrop(td);
 		if (dst != NULL) {
 			/*
 			 * Doubleword 0 of VSR0-VSR31 overlap with FPR0-FPR31 and
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
@@ -593,13 +593,13 @@
  * Keep this in sync with the assembly code in cpu_switch()!
  */
 void
-cpu_save_thread_regs(struct thread *td)
+cpu_update_pcb(struct thread *td)
 {
 	uint32_t pcb_flags;
 	struct pcb *pcb;
 
-	KASSERT(td == curthread,
-	    ("cpu_save_thread_regs: td is not curthread"));
+	if (td != curthread)
+		return;
 
 	pcb = td->td_pcb;
 
@@ -1109,8 +1109,7 @@
 	struct callframe *cf;
 
 	/* Ensure td0 pcb is up to date. */
-	if (td0 == curthread)
-		cpu_save_thread_regs(td0);
+	cpu_update_pcb(td0);
 
 	pcb2 = td->td_pcb;
 
diff --git a/sys/powerpc/powerpc/vm_machdep.c b/sys/powerpc/powerpc/vm_machdep.c
--- a/sys/powerpc/powerpc/vm_machdep.c
+++ b/sys/powerpc/powerpc/vm_machdep.c
@@ -120,8 +120,7 @@
 		return;
 
 	/* Ensure td1 is up to date before copy. */
-	if (td1 == curthread)
-		cpu_save_thread_regs(td1);
+	cpu_update_pcb(td1);
 
 	pcb = (struct pcb *)((td2->td_kstack +
 	    td2->td_kstack_pages * PAGE_SIZE - sizeof(struct pcb)) & ~0x2fUL);
diff --git a/sys/riscv/riscv/vm_machdep.c b/sys/riscv/riscv/vm_machdep.c
--- a/sys/riscv/riscv/vm_machdep.c
+++ b/sys/riscv/riscv/vm_machdep.c
@@ -249,6 +249,11 @@
 	td->td_pcb->pcb_sp = (uintptr_t)td->td_frame;
 }
 
+void
+cpu_update_pcb(struct thread *td)
+{
+}
+
 void
 cpu_exit(struct thread *td)
 {
diff --git a/sys/sys/proc.h b/sys/sys/proc.h
--- a/sys/sys/proc.h
+++ b/sys/sys/proc.h
@@ -1261,6 +1261,7 @@
 void	cpu_thread_free(struct thread *);
 void	cpu_thread_swapin(struct thread *);
 void	cpu_thread_swapout(struct thread *);
+void	cpu_update_pcb(struct thread *);
 struct	thread *thread_alloc(int pages);
 int	thread_check_susp(struct thread *td, bool sleep);
 void	thread_cow_get_proc(struct thread *newtd, struct proc *p);