Revert the vm_machdep.c part of r205072.

This causes a panic in vm_thread_dispose() when it tries to add this kstack
to the kstack cache. This happens only when 'td_kstack' is not (PAGE_SIZE * 2)
bytes aligned and we have unmapped the page at that address in cpu_thread_alloc.

Pointed out by: nwhitehorn@

1 files changed, 2 insertions, 18 deletions

diff --git a/sys/mips/mips/vm_machdep.c b/sys/mips/mips/vm_machdep.c
index 3f8e6cc..57219f6 100644
--- a/sys/mips/mips/vm_machdep.c
+++ b/sys/mips/mips/vm_machdep.c
@@ -214,16 +214,6 @@ cpu_thread_swapin(struct thread *td)
 {
 	pt_entry_t *pte;
 	int i;
-	vm_offset_t unused_kstack_page;
-
-	/*
-	 * Unmap the unused kstack page.
-	 */
-	unused_kstack_page = td->td_kstack;
-	if (td->td_md.md_realstack == td->td_kstack)
-		unused_kstack_page += (KSTACK_PAGES - 1) * PAGE_SIZE;
-
-	pmap_kremove(unused_kstack_page);
 
 	/*
 	 * The kstack may be at a different physical address now.
@@ -249,19 +239,13 @@ cpu_thread_swapout(struct thread *td)
 void
 cpu_thread_alloc(struct thread *td)
 {
-	vm_offset_t unused_kstack_page;
 	pt_entry_t *pte;
 	int i;
 
-	if (td->td_kstack & (1 << PAGE_SHIFT)) {
+	if (td->td_kstack & (1 << PAGE_SHIFT))
 		td->td_md.md_realstack = td->td_kstack + PAGE_SIZE;
-		unused_kstack_page = td->td_kstack;
-	} else {
+	else
 		td->td_md.md_realstack = td->td_kstack;
-		unused_kstack_page = td->td_kstack +
-					(KSTACK_PAGES - 1) * PAGE_SIZE;
-	}
-	pmap_kremove(unused_kstack_page);
 
 	td->td_pcb = (struct pcb *)(td->td_md.md_realstack +
 	    (td->td_kstack_pages - 1) * PAGE_SIZE) - 1;