Author: tkreuzer
Date: Wed Sep 21 23:02:24 2011
New Revision: 53797
URL: http://svn.reactos.org/svn/reactos?rev=53797&view=rev
Log:
[FREELDR]
Patch by Brian Palmer:
Fix problems that could occur, when the BIOS returns memory regions that are
not page aligned, by fixing up the bios memory map before using it.
Modified:
trunk/reactos/boot/freeldr/freeldr/arcemul/mm.c
Modified: trunk/reactos/boot/freeldr/freeldr/arcemul/mm.c
URL:
http://svn.reactos.org/svn/reactos/trunk/reactos/boot/freeldr/freeldr/arcemul/mm.c?rev=53797&r1=53796&r2=53797&view=diff
==============================================================================
--- trunk/reactos/boot/freeldr/freeldr/arcemul/mm.c [iso-8859-1] (original)
+++ trunk/reactos/boot/freeldr/freeldr/arcemul/mm.c [iso-8859-1] Wed Sep 21
23:02:24 2011
@@ -35,6 +35,49 @@
#endif
};
+
+static
+VOID MmFixupSystemMemoryMap(PBIOS_MEMORY_MAP BiosMemoryMap, ULONG* MapCount)
+{
+ int Index;
+ int Index2;
+ ULONGLONG BaseAddressOffset;
+
+ // Loop through each entry in the array
+ for (Index=0; Index<*MapCount; Index++)
+ {
+ // Correct all the addresses to be aligned on page boundaries
+ BaseAddressOffset = ROUND_UP(BiosMemoryMap[Index].BaseAddress,
MM_PAGE_SIZE) - BiosMemoryMap[Index].BaseAddress;
+ BiosMemoryMap[Index].BaseAddress += BaseAddressOffset;
+ if (BiosMemoryMap[Index].Length < BaseAddressOffset)
+ {
+ BiosMemoryMap[Index].Length = 0;
+ }
+ else
+ {
+ BiosMemoryMap[Index].Length -= BaseAddressOffset;
+ }
+ BiosMemoryMap[Index].Length =
ROUND_DOWN(BiosMemoryMap[Index].Length, MM_PAGE_SIZE);
+
+ // If the entry type isn't usable then remove
+ // it from the memory map (this will help reduce
+ // the size of our lookup table)
+ // If the length is less than a full page then
+ // get rid of it also.
+ if (BiosMemoryMap[Index].Type != BiosMemoryUsable ||
+ BiosMemoryMap[Index].Length < MM_PAGE_SIZE)
+ {
+ // Slide every entry after this down one
+ for (Index2=Index; Index2<(*MapCount - 1); Index2++)
+ {
+ BiosMemoryMap[Index2] = BiosMemoryMap[Index2 +
1];
+ }
+ (*MapCount)--;
+ Index--;
+ }
+ }
+}
+
const MEMORY_DESCRIPTOR*
ArcGetMemoryDescriptor(const MEMORY_DESCRIPTOR* Current)
{
@@ -57,6 +100,11 @@
BiosMemoryMapEntryCount = MachVtbl.GetMemoryMap(BiosMemoryMap,
sizeof(BiosMemoryMap) /
sizeof(BIOS_MEMORY_MAP));
+
+ //
+ // Fix entries that are not page aligned
+ //
+ MmFixupSystemMemoryMap(BiosMemoryMap, &BiosMemoryMapEntryCount);
//
// Copy the entries to our structure
