Index: head/sys/amd64/amd64/mp_machdep.c
===================================================================
--- head/sys/amd64/amd64/mp_machdep.c
+++ head/sys/amd64/amd64/mp_machdep.c
@@ -58,6 +58,7 @@
 #include <vm/vm_param.h>
 #include <vm/pmap.h>
 #include <vm/vm_kern.h>
+#include <vm/vm_map.h>
 #include <vm/vm_extern.h>
 
 #include <x86/apicreg.h>
@@ -297,7 +298,6 @@
 	pc->pc_gs32p = &gdt[NGDT * cpu + GUGS32_SEL];
 	pc->pc_ldt = (struct system_segment_descriptor *)&gdt[NGDT * cpu +
 	    GUSERLDT_SEL];
-	pc->pc_curpmap = kernel_pmap;
 	pc->pc_pcid_gen = 1;
 	pc->pc_pcid_next = PMAP_PCID_KERN + 1;
 	common_tss[cpu].tss_rsp0 = 0;
@@ -342,6 +342,7 @@
 	while (atomic_load_acq_int(&aps_ready) == 0)
 		ia32_pause();
 
+	pmap_activate_boot(vmspace_pmap(proc0.p_vmspace));
 	init_secondary_tail();
 }
 
Index: head/sys/amd64/amd64/pmap.c
===================================================================
--- head/sys/amd64/amd64/pmap.c
+++ head/sys/amd64/amd64/pmap.c
@@ -2655,9 +2655,7 @@
 			__pcpu[i].pc_ucr3 = PMAP_NO_CR3;
 		}
 	}
-	PCPU_SET(curpmap, kernel_pmap);
-	pmap_activate(curthread);
-	CPU_FILL(&kernel_pmap->pm_active);
+	pmap_activate_boot(pmap);
 }
 
 void
@@ -7529,7 +7527,7 @@
 			intr_restore(rflags);
 		if (cached)
 			PCPU_INC(pm_save_cnt);
-	} else if (cr3 != pmap->pm_cr3) {
+	} else {
 		load_cr3(pmap->pm_cr3);
 		PCPU_SET(curpmap, pmap);
 		if (pti) {
@@ -7557,6 +7555,26 @@
 	critical_enter();
 	pmap_activate_sw(td);
 	critical_exit();
+}
+
+void
+pmap_activate_boot(pmap_t pmap)
+{
+	u_int cpuid;
+
+	/*
+	 * kernel_pmap must be never deactivated, and we ensure that
+	 * by never activating it at all.
+	 */
+	MPASS(pmap != kernel_pmap);
+
+	cpuid = PCPU_GET(cpuid);
+#ifdef SMP
+	CPU_SET_ATOMIC(cpuid, &pmap->pm_active);
+#else
+	CPU_SET(cpuid, &pmap->pm_active);
+#endif
+	PCPU_SET(curpmap, pmap);
 }
 
 void
Index: head/sys/amd64/include/pmap.h
===================================================================
--- head/sys/amd64/include/pmap.h
+++ head/sys/amd64/include/pmap.h
@@ -407,6 +407,7 @@
 
 struct thread;
 
+void	pmap_activate_boot(pmap_t pmap);
 void	pmap_activate_sw(struct thread *);
 void	pmap_bootstrap(vm_paddr_t *);
 int	pmap_cache_bits(pmap_t pmap, int mode, boolean_t is_pde);