Set the current pmap in macppc's pmap_activate

This fixes a possible freeze in execve(2).  It sometimes froze when a
dual-cpu macppc started daemons during boot.  There is a chance that
uvm_map.c uvmspace_exec sees ovm->vm_refcnt != 1 and switches curproc
to a new pmap.  If this happened, then execve froze by trying to
copyout to the wrong pmap; curpcb->pcb_pm was old.  Fix by setting
pointers when uvmspace_exec calls pmap_activate.

ok miod@

diff --git a/sys/arch/powerpc/powerpc/pmap.c b/sys/arch/powerpc/powerpc/pmap.c
index e47eafa..f160e2e 100644 (file)
--- a/sys/arch/powerpc/powerpc/pmap.c
+++ b/sys/arch/powerpc/powerpc/pmap.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: pmap.c,v 1.181 2023/02/06 06:41:38 gkoehler Exp $ */
+/*     $OpenBSD: pmap.c,v 1.182 2023/02/21 04:49:43 gkoehler Exp $ */
 
 /*
  * Copyright (c) 2015 Martin Pieuchot
@@ -81,6 +81,7 @@
 #include <sys/queue.h>
 #include <sys/pool.h>
 #include <sys/atomic.h>
+#include <sys/user.h>
 
 #include <uvm/uvm_extern.h>
 
@@ -1646,12 +1647,19 @@ pmap_enable_mmu(void)
 
 /*
  * activate a pmap entry
- * NOOP on powerpc, all PTE entries exist in the same hash table.
+ * All PTE entries exist in the same hash table.
  * Segment registers are filled on exit to user mode.
  */
 void
 pmap_activate(struct proc *p)
 {
+       struct pcb *pcb = &p->p_addr->u_pcb;
+
+       /* Set the current pmap. */
+       pcb->pcb_pm = p->p_vmspace->vm_map.pmap;
+       pmap_extract(pmap_kernel(),
+           (vaddr_t)pcb->pcb_pm, (paddr_t *)&pcb->pcb_pmreal);
+       curcpu()->ci_curpm = pcb->pcb_pmreal;
 }
 
 /*