Module Name: src
Committed By: maxv
Date: Thu Feb 9 19:30:56 UTC 2017
Modified Files:
src/sys/arch/amd64/amd64: locore.S
Log Message:
If the preloaded modules cannot be mapped with the initial amount of VA,
discard the associated bootinfo entry. Otherwise the machine faults and
reboots immediately.
I spotted this bug more than a year ago, but I recently saw that there is
already PR/42645 (7 years old), so just fix it. The size has been increased
in the meantime, so the limit is unlikely to be reached anyway.
To generate a diff of this commit:
cvs rdiff -u -r1.120 -r1.121 src/sys/arch/amd64/amd64/locore.S
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/arch/amd64/amd64/locore.S
diff -u src/sys/arch/amd64/amd64/locore.S:1.120 src/sys/arch/amd64/amd64/locore.S:1.121
--- src/sys/arch/amd64/amd64/locore.S:1.120 Thu Feb 9 08:23:46 2017
+++ src/sys/arch/amd64/amd64/locore.S Thu Feb 9 19:30:56 2017
@@ -1,4 +1,4 @@
-/* $NetBSD: locore.S,v 1.120 2017/02/09 08:23:46 maxv Exp $ */
+/* $NetBSD: locore.S,v 1.121 2017/02/09 19:30:56 maxv Exp $ */
/*
* Copyright-o-rama!
@@ -211,6 +211,10 @@
((NKL4_KIMG_ENTRIES + TABLE_L3_ENTRIES + TABLE_L2_ENTRIES + 1 + UPAGES) \
* PAGE_SIZE)
+/* Amount of VA used to map the kernel, the syms and the preloaded modules */
+#define BOOTMAP_VA_SIZE \
+ (NKL2_KIMG_ENTRIES * (1 << L2_SHIFT) - TABLESIZE - IOM_SIZE)
+
/*
* fillkpt - Fill in a kernel page table
* eax = pte (page frame | control | status)
@@ -443,7 +447,7 @@ ENTRY(start)
testl %eax,%eax /* bootinfo = NULL? */
jz bootinfo_finished
- movl (%eax),%ebx /* number of entries */
+ movl (%eax),%ebx /* bootinfo::bi_nentries */
movl $RELOC(bootinfo),%ebp
movl %ebp,%edx
addl $BOOTINFO_MAXSIZE,%ebp
@@ -462,7 +466,7 @@ bootinfo_entryloop:
movl (%ecx),%eax /* btinfo_common::len (size of entry) */
movl %edx,%edi
- addl (%ecx),%edx /* update dest pointer */
+ addl %eax,%edx /* update dest pointer */
cmpl %ebp,%edx /* beyond bootinfo+BOOTINFO_MAXSIZE? */
jg bootinfo_overflow
@@ -470,20 +474,31 @@ bootinfo_entryloop:
movl %eax,%ecx
/*
- * If any modules were loaded, record where they end. We'll need to
- * skip over them.
+ * If any modules were loaded, record where they end. 'eblob' is used
+ * later to compute the initial bootstrap tables.
*/
cmpl $BTINFO_MODULELIST,4(%esi) /* btinfo_common::type */
- jne 0f
+ jne bootinfo_copy
- pushl 12(%esi) /* btinfo_modulelist::endpa */
- popl RELOC(eblob)
+ /* Skip the modules if we won't have enough VA to map them */
+ movl 12(%esi),%eax /* btinfo_modulelist::endpa */
+ addl $PGOFSET,%eax /* roundup to a page */
+ andl $~PGOFSET,%eax
+ cmpl $BOOTMAP_VA_SIZE,%eax
+ jg bootinfo_skip
+ movl %eax,RELOC(eblob)
addl $KERNBASE_LO,RELOC(eblob)
adcl $KERNBASE_HI,RELOC(eblob)+4
-0:
+bootinfo_copy:
rep
movsb /* copy esi -> edi */
+ jmp bootinfo_next
+
+bootinfo_skip:
+ subl %ecx,%edx /* revert dest pointer */
+
+bootinfo_next:
popl %eax
popl %esi
popl %edi
@@ -501,8 +516,8 @@ bootinfo_overflow:
movl $RELOC(bootinfo),%ebp
movl %ebp,%edx
subl %ebx,(%edx) /* correct the number of entries */
-
bootinfo_finished:
+
/* Load 'esym' */
movl 16(%esp),%eax
testl %eax,%eax /* esym = NULL? */
