[src/trunk]: src/sys/arch/amd64/amd64 fix sparse crash dumps to contain enoug...

[chs <chs%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/eed11de826fc
branches:  trunk
changeset: 782669:eed11de826fc
user:      chs <chs%NetBSD.org@localhost>
date:      Tue Nov 13 14:09:36 2012 +0000

description:
fix sparse crash dumps to contain enough data to be useful,
in particular the top-level page table pages.
use pmap_kremove_local() while writing crash dumps
to avoid spurious warning messages.

diffstat:

 sys/arch/amd64/amd64/machdep.c |  56 +++++++++++++++++++++++------------------
 1 files changed, 31 insertions(+), 25 deletions(-)

diffs (113 lines):

diff -r 1534c80bed14 -r eed11de826fc sys/arch/amd64/amd64/machdep.c
--- a/sys/arch/amd64/amd64/machdep.c    Tue Nov 13 14:08:07 2012 +0000
+++ b/sys/arch/amd64/amd64/machdep.c    Tue Nov 13 14:09:36 2012 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: machdep.c,v 1.190 2012/09/03 05:01:44 cherry Exp $     */
+/*     $NetBSD: machdep.c,v 1.191 2012/11/13 14:09:36 chs Exp $        */
 
 /*-
  * Copyright (c) 1996, 1997, 1998, 2000, 2006, 2007, 2008, 2011
@@ -111,7 +111,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: machdep.c,v 1.190 2012/09/03 05:01:44 cherry Exp $");
+__KERNEL_RCSID(0, "$NetBSD: machdep.c,v 1.191 2012/11/13 14:09:36 chs Exp $");
 
 /* #define XENDEBUG_LOW  */
 
@@ -317,7 +317,7 @@
 
 #ifndef NO_SPARSE_DUMP
 void sparse_dump_reset(void);
-void sparse_dump_mark(vaddr_t, vaddr_t, int);
+void sparse_dump_mark(void);
 void cpu_dump_prep_sparse(void);
 #endif
 
@@ -821,7 +821,7 @@
  * XXXfvdl share dumpcode.
  */
 
- /*
+/*
  * Perform assorted dump-related initialization tasks.  Assumes that
  * the maximum physical memory address will not increase afterwards.
  */
@@ -873,34 +873,39 @@
 }
 
 /*
- * Include or exclude pages in a sparse dump, by half-open virtual
- * address interval (which may wrap around the end of the space).
+ * Include or exclude pages in a sparse dump.
  */
 void
-sparse_dump_mark(vaddr_t vbegin, vaddr_t vend, int includep)
+sparse_dump_mark(void)
 {
-       pmap_t pmap;
-       paddr_t p;
-       vaddr_t v;
+       paddr_t p, pstart, pend;
+       struct vm_page *pg;
+       int i;
 
        /*
-        * If a partial page is called for, the whole page must be included.
+        * Mark all memory pages, then unmark pages that are uninteresting.
+        * Dereferenceing pg->uobject might crash again if another CPU
+        * frees the object out from under us, but we can't lock anything
+        * so it's a risk we have to take.
         */
-       if (includep) {
-               vbegin = rounddown(vbegin, PAGE_SIZE);
-               vend = roundup(vend, PAGE_SIZE);
-       } else {
-               vbegin = roundup(vbegin, PAGE_SIZE);
-               vend = rounddown(vend, PAGE_SIZE);
+
+       for (i = 0; i < mem_cluster_cnt; ++i) {
+               pstart = mem_clusters[i].start / PAGE_SIZE;
+               pend = pstart + mem_clusters[i].size / PAGE_SIZE;
+
+               for (p = pstart; p < pend; p++) {
+                       setbit(sparse_dump_physmap, p);
+               }
        }
+       for (i = 0; i < vm_nphysseg; i++) {
+               struct vm_physseg *seg = VM_PHYSMEM_PTR(i);
 
-       pmap = pmap_kernel();
-       for (v = vbegin; v != vend; v += PAGE_SIZE) {
-               if (pmap_extract(pmap, v, &p)) {
-                       if (includep)
-                               setbit(sparse_dump_physmap, p/PAGE_SIZE);
-                       else
-                               clrbit(sparse_dump_physmap, p/PAGE_SIZE);
+               for (pg = seg->pgs; pg < seg->lastpg; pg++) {
+                       if (pg->uanon || (pg->pqflags & PQ_FREE) ||
+                           (pg->uobject && pg->uobject->pgops)) {
+                               p = VM_PAGE_TO_PHYS(pg) / PAGE_SIZE;
+                               clrbit(sparse_dump_physmap, p);
+                       }
                }
        }
 }
@@ -914,7 +919,7 @@
 {
        sparse_dump_reset();
        /* XXX could the alternate recursive page table be skipped? */
-       sparse_dump_mark((vaddr_t)PTE_BASE, (vaddr_t)KERN_BASE, 1);
+       sparse_dump_mark();
        /* Memory for I/O buffers could be unmarked here, for example. */
        /* The kernel text could also be unmarked, but gdb would be upset. */
 }
@@ -1206,6 +1211,7 @@
                pmap_update(pmap_kernel());
 
                error = (*dump)(dumpdev, blkno, (void *)dumpspace, n);
+               pmap_kremove_local(dumpspace, n);
                if (error)
                        return error;
                maddr += n;