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[FREELDR] Fix calculation of page lookup table (#761)

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On x64 we only map 1GB of pages, so adjust MM_MAX_PAGE accordingly and also respect that value when searching for the best location of the page lookup table.
CORE-11048 #resolve
This commit is contained in:
Timo Kreuzer 2018-08-18 12:16:33 +02:00 committed by GitHub
parent 27c3a4d26a
commit 6da93539a9
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GPG key ID: 4AEE18F83AFDEB23
2 changed files with 20 additions and 13 deletions
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3
boot/freeldr/freeldr/include/mm.h
View file

@ -58,8 +58,7 @@ typedef struct _FREELDR_MEMORY_DESCRIPTOR
#define MM_PAGE_SIZE 4096
#define MM_PAGE_MASK 0xFFF
#define MM_PAGE_SHIFT 12
// FIXME: freeldr implementation uses ULONG for page numbers
#define MM_MAX_PAGE 0xFFFFFFFFFFFFF
#define MM_MAX_PAGE 0x3FFFF /* freeldr only maps 1 GB */
#define MM_SIZE_TO_PAGES(a) \
( ((a) >> MM_PAGE_SHIFT) + ((a) & MM_PAGE_MASK ? 1 : 0) )

30
boot/freeldr/freeldr/lib/mm/meminit.c
View file

@ -415,13 +415,15 @@ PVOID MmFindLocationForPageLookupTable(PFN_NUMBER TotalPageCount)
{
const FREELDR_MEMORY_DESCRIPTOR* MemoryDescriptor = NULL;
SIZE_T PageLookupTableSize;
PFN_NUMBER PageLookupTablePages;
PFN_NUMBER PageLookupTableStartPage = 0;
PFN_NUMBER RequiredPages;
PFN_NUMBER CandidateBasePage = 0;
PFN_NUMBER CandidatePageCount;
PFN_NUMBER PageLookupTableEndPage;
PVOID PageLookupTableMemAddress = NULL;
// Calculate how much pages we need to keep the page lookup table
PageLookupTableSize = TotalPageCount * sizeof(PAGE_LOOKUP_TABLE_ITEM);
PageLookupTablePages = PageLookupTableSize / MM_PAGE_SIZE;
RequiredPages = PageLookupTableSize / MM_PAGE_SIZE;
// Search the highest memory block big enough to contain lookup table
while ((MemoryDescriptor = ArcGetMemoryDescriptor(MemoryDescriptor)) != NULL)
@ -429,22 +431,28 @@ PVOID MmFindLocationForPageLookupTable(PFN_NUMBER TotalPageCount)
// Continue, if memory is not free
if (MemoryDescriptor->MemoryType != LoaderFree) continue;
// Continue, if the block is not big enough?
if (MemoryDescriptor->PageCount < PageLookupTablePages) continue;
// Continue, if the block is not big enough
if (MemoryDescriptor->PageCount < RequiredPages) continue;
// Continue, if it is not at a higher address than previous address
if (MemoryDescriptor->BasePage < PageLookupTableStartPage) continue;
if (MemoryDescriptor->BasePage < CandidateBasePage) continue;
// Continue, if the address is too high
if (MemoryDescriptor->BasePage >= MM_MAX_PAGE) continue;
if (MemoryDescriptor->BasePage + RequiredPages >= MM_MAX_PAGE) continue;
// Memory block is more suitable than the previous one
PageLookupTableStartPage = MemoryDescriptor->BasePage;
PageLookupTableMemAddress = (PVOID)((ULONG_PTR)
(MemoryDescriptor->BasePage + MemoryDescriptor->PageCount) * MM_PAGE_SIZE
- PageLookupTableSize);
CandidateBasePage = MemoryDescriptor->BasePage;
CandidatePageCount = MemoryDescriptor->PageCount;
}
// Calculate the end address for the lookup table
PageLookupTableEndPage = min(CandidateBasePage + CandidatePageCount,
MM_MAX_PAGE);
// Calculate the virtual address
PageLookupTableMemAddress = (PVOID)((PageLookupTableEndPage * PAGE_SIZE)
- PageLookupTableSize);
TRACE("MmFindLocationForPageLookupTable() returning 0x%x\n", PageLookupTableMemAddress);
return PageLookupTableMemAddress;