[src/trunk]: src/sys/arch/amd64/stand/prekern Oh, damn. Obviously I forgot on...

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

details:   https://anonhg.NetBSD.org/src/rev/801f1f0e5dd4
branches:  trunk
changeset: 828069:801f1f0e5dd4
user:      maxv <maxv%NetBSD.org@localhost>
date:      Sun Nov 26 14:29:48 2017 +0000

description:
Oh, damn. Obviously I forgot one case here: an already-mapped region could
be contained entirely in the region we're trying to create. So go through
another round. While here add mm_reenter_pa, and make sure the va given to
mm_enter_pa does not already point to something.

diffstat:

 sys/arch/amd64/stand/prekern/mm.c |  19 ++++++++++++++++---
 1 files changed, 16 insertions(+), 3 deletions(-)

diffs (54 lines):

diff -r ebe391b1aa62 -r 801f1f0e5dd4 sys/arch/amd64/stand/prekern/mm.c
--- a/sys/arch/amd64/stand/prekern/mm.c Sun Nov 26 12:48:44 2017 +0000
+++ b/sys/arch/amd64/stand/prekern/mm.c Sun Nov 26 14:29:48 2017 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: mm.c,v 1.19 2017/11/26 11:01:09 maxv Exp $     */
+/*     $NetBSD: mm.c,v 1.20 2017/11/26 14:29:48 maxv Exp $     */
 
 /*
  * Copyright (c) 2017 The NetBSD Foundation, Inc. All rights reserved.
@@ -71,6 +71,15 @@
 static void
 mm_enter_pa(paddr_t pa, vaddr_t va, pte_prot_t prot)
 {
+       if (PTE_BASE[pl1_i(va)] & PG_V) {
+               fatal("mm_enter_pa: mapping already present");
+       }
+       PTE_BASE[pl1_i(va)] = pa | PG_V | protection_codes[prot];
+}
+
+static void
+mm_reenter_pa(paddr_t pa, vaddr_t va, pte_prot_t prot)
+{
        PTE_BASE[pl1_i(va)] = pa | PG_V | protection_codes[prot];
 }
 
@@ -92,7 +101,7 @@
 
        /* Zero them out */
        for (i = 0; i < npages; i++) {
-               mm_enter_pa(pa + i * PAGE_SIZE, tmpva,
+               mm_reenter_pa(pa + i * PAGE_SIZE, tmpva,
                    MM_PROT_READ|MM_PROT_WRITE);
                mm_flush_va(tmpva);
                memset((void *)tmpva, 0, PAGE_SIZE);
@@ -120,7 +129,7 @@
        for (i = 0; i < npages; i++) {
                va = startva + i * PAGE_SIZE;
                pa = (PTE_BASE[pl1_i(va)] & PG_FRAME);
-               mm_enter_pa(pa, va, prot);
+               mm_reenter_pa(pa, va, prot);
                mm_flush_va(va);
        }
 }
@@ -227,6 +236,10 @@
                                ok = false;
                                break;
                        }
+                       if (randva < sva && eva < (randva + size)) {
+                               ok = false;
+                               break;
+                       }
                }
                if (ok) {
                        break;