[src/trunk]: src/sys/arch/usermode/usermode Don't dynamically allocate memory...

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

details:   https://anonhg.NetBSD.org/src/rev/b2c1381b2877
branches:  trunk
changeset: 361896:b2c1381b2877
user:      reinoud <reinoud%NetBSD.org@localhost>
date:      Thu May 17 19:06:02 2018 +0000

description:
Don't dynamically allocate memory we are only going to use once; so allocate
it on the stack.

While here, also include some more sanity checks.

diffstat:

 sys/arch/usermode/usermode/pmap.c |  19 ++++++++++---------
 1 files changed, 10 insertions(+), 9 deletions(-)

diffs (81 lines):

diff -r 0885f16e8846 -r b2c1381b2877 sys/arch/usermode/usermode/pmap.c
--- a/sys/arch/usermode/usermode/pmap.c Thu May 17 19:00:39 2018 +0000
+++ b/sys/arch/usermode/usermode/pmap.c Thu May 17 19:06:02 2018 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: pmap.c,v 1.106 2016/07/07 06:55:39 msaitoh Exp $ */
+/* $NetBSD: pmap.c,v 1.107 2018/05/17 19:06:02 reinoud Exp $ */
 
 /*-
  * Copyright (c) 2011 Reinoud Zandijk <reinoud%NetBSD.org@localhost>
@@ -27,7 +27,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: pmap.c,v 1.106 2016/07/07 06:55:39 msaitoh Exp $");
+__KERNEL_RCSID(0, "$NetBSD: pmap.c,v 1.107 2018/05/17 19:06:02 reinoud Exp $");
 
 #include "opt_memsize.h"
 #include "opt_kmempages.h"
@@ -230,6 +230,7 @@
        mem_fh = thunk_mkstemp(mem_name);
        if (mem_fh < 0)
                panic("pmap_bootstrap: can't create memory file\n");
+
        /* unlink the file so space is freed when we quit */
        if (thunk_unlink(mem_name) == -1)
                panic("pmap_bootstrap: can't unlink %s", mem_name);
@@ -247,19 +248,14 @@
        }
 #else
        {
-               void *block;
+               char block[PAGE_SIZE];
 
                printf("Creating memory file\r");
-               block = thunk_malloc(PAGE_SIZE);
-               if (!block)
-                       panic("pmap_bootstrap: can't malloc writeout block");
-
                for (pg = 0; pg < file_len; pg += PAGE_SIZE) {
                        wlen = thunk_pwrite(mem_fh, block, PAGE_SIZE, pg);
                        if (wlen != PAGE_SIZE)
                                panic("pmap_bootstrap: write fails, disc full?");
                }
-               thunk_free(block);
        }
 #endif
 
@@ -1204,13 +1200,14 @@
        if (pa & (PAGE_SIZE-1))
                panic("%s: unaligned address passed : %p\n", __func__, (void *) pa);
 
-       /* XXX bug alart: can we allow the kernel to make a decision on this? */
        blob = thunk_mmap(NULL, PAGE_SIZE,
                THUNK_PROT_READ | THUNK_PROT_WRITE,
                THUNK_MAP_FILE | THUNK_MAP_SHARED,
                mem_fh, pa);
        if (!blob)
                panic("%s: couldn't get mapping", __func__);
+       if (blob < (char *) kmem_k_end)
+               panic("%s: mmap in illegal memory range", __func__);
 
        memset(blob, 0, PAGE_SIZE);
 
@@ -1237,6 +1234,8 @@
                mem_fh, src_pa);
        if (!sblob)
                panic("%s: couldn't get src mapping", __func__);
+       if (sblob < (char *) kmem_k_end)
+               panic("%s: mmap in illegal memory range", __func__);
 
        /* XXX bug alart: can we allow the kernel to make a decision on this? */
        dblob = thunk_mmap(NULL, PAGE_SIZE,
@@ -1245,6 +1244,8 @@
                mem_fh, dst_pa);
        if (!dblob)
                panic("%s: couldn't get dst mapping", __func__);
+       if (dblob < (char *) kmem_k_end)
+               panic("%s: mmap in illegal memory range", __func__);
 
        memcpy(dblob, sblob, PAGE_SIZE);