Polish previous commit:

o  Replace KSTACK_PAGES with pages on panic() in pmap_new_thread(),
o  Fix style bugs in adjacent code,
o  Use NULL instead of 0 for pointers,
o  Save the virtual kstack address if we create an alternate
   kstack because 1) we can derive the physical (RR7) address
   from it and 2) we need the virtual address for contigfree()
   in pmap_dispose_thread(). Thus td_altkstack saves
   td_md.md_kstackvirt.

1 files changed, 18 insertions, 13 deletions

diff --git a/sys/ia64/ia64/pmap.c b/sys/ia64/ia64/pmap.c
index 66634d7..103df45 100644
--- a/sys/ia64/ia64/pmap.c
+++ b/sys/ia64/ia64/pmap.c
@@ -736,16 +736,12 @@ pmap_new_thread(struct thread *td, int pages)
 	 * 7 address for it which makes it impossible to accidentally
 	 * lose when recording a trapframe.
 	 */
-	ks = contigmalloc(pages * PAGE_SIZE, M_PMAP,
-			  M_WAITOK,
-			  0ul,
-			  256*1024*1024 - 1,
-			  PAGE_SIZE,
-			  256*1024*1024);
-
+	ks = contigmalloc(pages * PAGE_SIZE, M_PMAP, M_WAITOK, 0ul,
+	    256*1024*1024 - 1, PAGE_SIZE, 256*1024*1024);
 	if (ks == NULL)
 		panic("pmap_new_thread: could not contigmalloc %d pages\n",
-		    KSTACK_PAGES);
+		    pages);
+
 	td->td_md.md_kstackvirt = ks;
 	td->td_kstack = IA64_PHYS_TO_RR7(ia64_tpa((u_int64_t)ks));
 	td->td_kstack_pages = pages;
@@ -762,7 +758,7 @@ pmap_dispose_thread(struct thread *td)
 
 	pages = td->td_kstack_pages;
 	contigfree(td->td_md.md_kstackvirt, pages * PAGE_SIZE, M_PMAP);
-	td->td_md.md_kstackvirt = 0;
+	td->td_md.md_kstackvirt = NULL;
 	td->td_kstack = 0;
 }
 
@@ -773,9 +769,14 @@ void
 pmap_new_altkstack(struct thread *td, int pages)
 {
 
-	/* shuffle the original stack */
+	/*
+	 * Shuffle the original stack. Save the virtual kstack address
+	 * instead of the physical address because 1) we can derive the
+	 * physical address from the virtual address and 2) we need the
+	 * virtual address in pmap_dispose_thread.
+	 */
 	td->td_altkstack_obj = td->td_kstack_obj;
-	td->td_altkstack = td->td_kstack;
+	td->td_altkstack = (vm_offset_t)td->td_md.md_kstackvirt;
 	td->td_altkstack_pages = td->td_kstack_pages;
 
 	pmap_new_thread(td, pages);
@@ -787,8 +788,12 @@ pmap_dispose_altkstack(struct thread *td)
 
 	pmap_dispose_thread(td);
 
-	/* restore the original kstack */
-	td->td_kstack = td->td_altkstack;
+	/*
+	 * Restore the original kstack. Note that td_altkstack holds the
+	 * virtual kstack address of the previous kstack.
+	 */
+	td->td_md.md_kstackvirt = (void*)td->td_altkstack;
+	td->td_kstack = IA64_PHYS_TO_RR7(ia64_tpa(td->td_altkstack));
 	td->td_kstack_obj = td->td_altkstack_obj;
 	td->td_kstack_pages = td->td_altkstack_pages;
 	td->td_altkstack = 0;