[src/trunk]: src/sys/uvm PR kern/54395

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

details:   https://anonhg.NetBSD.org/src/rev/c6c4aec8676e
branches:  trunk
changeset: 460709:c6c4aec8676e
user:      rin <rin%NetBSD.org@localhost>
date:      Fri Nov 01 08:26:18 2019 +0000

description:
PR kern/54395

- Align hint for virtual address at the beginning of uvm_map() if
  required. Otherwise, it will be rounded up/down in an unexpected
  way by uvm_map_space_avail(), which results in assertion failure.

  Fix kernel panic when executing earm binary (8KB pages) on aarch64
  (4KB pages), which relies on mmap(2) with MAP_ALIGNED flag.

- Use inline functions/macros consistently.

- Add some more KASSERT's.

For more details, see the PR as well as discussion on port-kern:
http://mail-index.netbsd.org/tech-kern/2019/10/27/msg025629.html

diffstat:

 sys/uvm/uvm_map.c |  40 ++++++++++++++++++++++++++++++----------
 1 files changed, 30 insertions(+), 10 deletions(-)

diffs (89 lines):

diff -r 49eeba9d66ad -r c6c4aec8676e sys/uvm/uvm_map.c
--- a/sys/uvm/uvm_map.c Fri Nov 01 04:28:14 2019 +0000
+++ b/sys/uvm/uvm_map.c Fri Nov 01 08:26:18 2019 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: uvm_map.c,v 1.364 2019/08/10 01:06:45 mrg Exp $        */
+/*     $NetBSD: uvm_map.c,v 1.365 2019/11/01 08:26:18 rin Exp $        */
 
 /*
  * Copyright (c) 1997 Charles D. Cranor and Washington University.
@@ -66,7 +66,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: uvm_map.c,v 1.364 2019/08/10 01:06:45 mrg Exp $");
+__KERNEL_RCSID(0, "$NetBSD: uvm_map.c,v 1.365 2019/11/01 08:26:18 rin Exp $");
 
 #include "opt_ddb.h"
 #include "opt_pax.h"
@@ -187,6 +187,23 @@
  */
 
 /*
+ * uvm_map_align_va: round down or up virtual address
+ */
+static __inline void
+uvm_map_align_va(vaddr_t *vap, vsize_t align, int topdown)
+{
+
+       KASSERT(powerof2(align));
+
+       if (align != 0 && (*vap & (align - 1)) != 0) {
+               if (topdown)
+                       *vap = rounddown2(*vap, align);
+               else
+                       *vap = roundup2(*vap, align);
+       }
+}
+
+/*
  * UVM_ET_ISCOMPATIBLE: check some requirements for map entry merging
  */
 extern struct vm_map *pager_map;
@@ -1063,6 +1080,7 @@
        int error;
 
        KASSERT((size & PAGE_MASK) == 0);
+       KASSERT((flags & UVM_FLAG_FIXED) == 0 || align == 0);
 
        /*
         * for pager_map, allocate the new entry first to avoid sleeping
@@ -1805,13 +1823,9 @@
                                *start = ptoa(hint + align); /* adjust to color */
                        }
                }
-       } else if (align != 0) {
-               if ((*start & (align - 1)) != 0) {
-                       if (topdown)
-                               *start &= ~(align - 1);
-                       else
-                               *start = roundup(*start, align);
-               }
+       } else {
+               KASSERT(powerof2(align));
+               uvm_map_align_va(start, align, topdown);
                /*
                 * XXX Should we PMAP_PREFER() here again?
                 * eh...i think we're okay
@@ -1861,7 +1875,7 @@
 
        UVMHIST_LOG(maphist, "(map=%#jx, hint=%#jx, len=%ju, flags=%#jx)",
            (uintptr_t)map, hint, length, flags);
-       KASSERT((flags & UVM_FLAG_COLORMATCH) != 0 || (align & (align - 1)) == 0);
+       KASSERT((flags & UVM_FLAG_COLORMATCH) != 0 || powerof2(align));
        KASSERT((flags & UVM_FLAG_COLORMATCH) == 0 || align < uvmexp.ncolors);
        KASSERT((flags & UVM_FLAG_FIXED) == 0 || align == 0);
 
@@ -1888,6 +1902,12 @@
        }
 
        /*
+        * hint may not be aligned properly; we need round up or down it
+        * before proceeding further.
+        */
+       uvm_map_align_va(&hint, align, topdown);
+
+       /*
         * Look for the first possible address; if there's already
         * something at this address, we have to start after it.
         */