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Clear the page tables on creation, use macros for counts.

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This makes it less likely that uninitialized entries cause troubles.
Also panic if we encounter an unknown entry type instead of defaulting
to 4K pages.
This commit is contained in:
Michael Lotz 2012-12-03 22:51:39 +01:00
parent 89564c0a10
commit a438da7c8b
1 changed files with 17 additions and 6 deletions
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23
src/system/boot/arch/arm/arch_mmu.cpp
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@ -253,27 +253,38 @@ get_next_page_table(uint32 type)
sNextPageTableAddress, kPageTableRegionEnd, type));
size_t size = 0;
size_t entryCount = 0;
switch (type) {
case ARM_MMU_L1_TYPE_COARSE:
default:
size = ARM_MMU_L2_COARSE_TABLE_SIZE;
entryCount = ARM_MMU_L2_COARSE_ENTRY_COUNT;
break;
case ARM_MMU_L1_TYPE_FINE:
size = ARM_MMU_L2_FINE_TABLE_SIZE;
entryCount = ARM_MMU_L2_FINE_ENTRY_COUNT;
break;
case ARM_MMU_L1_TYPE_SECTION:
// TODO: Figure out parameters for section types.
size = 16384;
break;
default:
panic("asked for unknown page table type: %#" B_PRIx32 "\n", type);
return NULL;
}
addr_t address = sNextPageTableAddress;
if (address >= kPageTableRegionEnd) {
TRACE(("outside of pagetableregion!\n"));
return (uint32 *)get_next_physical_address_alligned(size, 0xffffffc0);
if (address < kPageTableRegionEnd)
sNextPageTableAddress += size;
else {
TRACE(("page table allocation outside of pagetable region!\n"));
address = get_next_physical_address_alligned(size, 0xffffffc0);
}
sNextPageTableAddress += size;
return (uint32 *)address;
uint32 *pageTable = (uint32 *)address;
for (size_t i = 0; i < entryCount; i++)
pageTable[i] = 0;
return pageTable;
}