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Simplify the page directory init loops.

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Also check and possibly reuse an existing page directory entry. This
makes the possible memory maps a little more flexible.
This commit is contained in:
Michael Lotz
2012-12-04 23:38:04 +01:00
parent 50c463f4f1
commit 89564c0a10
1 changed files with 41 additions and 19 deletions
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src/system/boot/arch/arm/arch_mmu.cpp
+41 -19
View File
@@ -277,6 +277,33 @@ get_next_page_table(uint32 type)
}
static uint32 *
get_or_create_page_table(addr_t address, uint32 type)
{
uint32 *pageTable = NULL;
uint32 pageDirectoryIndex = VADDR_TO_PDENT(address);
uint32 pageDirectoryEntry = sPageDirectory[pageDirectoryIndex];
uint32 entryType = pageDirectoryEntry & ARM_PDE_TYPE_MASK;
if (entryType == ARM_MMU_L1_TYPE_FAULT) {
// This page directory entry has not been set yet, allocate it.
pageTable = get_next_page_table(type);
sPageDirectory[pageDirectoryIndex] = (uint32)pageTable | type;
return pageTable;
}
if (entryType != type) {
// This entry has been allocated with a different type!
panic("tried to reuse page directory entry %" B_PRIu32
" with different type (entry: %#" B_PRIx32 ", new type: %#" B_PRIx32
")\n", pageDirectoryIndex, pageDirectoryEntry, type);
return NULL;
}
return (uint32 *)(pageDirectoryEntry & ARM_PDE_ADDRESS_MASK);
}
void
init_page_directory()
{
@@ -295,33 +322,28 @@ init_page_directory()
for (uint32 i = 0; i < ARM_MMU_L1_TABLE_ENTRY_COUNT; i++)
sPageDirectory[i] = 0;
uint32 *pageTable = NULL;
for (uint32 i = 0; i < ARRAY_SIZE(LOADER_MEMORYMAP); i++) {
pageTable = get_next_page_table(ARM_MMU_L1_TYPE_COARSE);
TRACE(("BLOCK: %s START: %lx END %lx\n", LOADER_MEMORYMAP[i].name,
LOADER_MEMORYMAP[i].start, LOADER_MEMORYMAP[i].end));
addr_t pos = LOADER_MEMORYMAP[i].start;
int c = 0;
while (pos < LOADER_MEMORYMAP[i].end) {
pageTable[c] = pos | LOADER_MEMORYMAP[i].flags | smallType;
addr_t address = LOADER_MEMORYMAP[i].start;
ASSERT((address & ~ARM_PTE_ADDRESS_MASK) == 0);
c++;
if (c > 255) { // we filled a pagetable => we need a new one
// there is 1MB per pagetable so:
sPageDirectory[VADDR_TO_PDENT(pos)]
= (uint32)pageTable | ARM_MMU_L1_TYPE_COARSE;
pageTable = get_next_page_table(ARM_MMU_L1_TYPE_COARSE);
c = 0;
uint32 *pageTable = NULL;
uint32 pageTableIndex = 0;
while (address < LOADER_MEMORYMAP[i].end) {
if (pageTable == NULL
|| pageTableIndex >= ARM_MMU_L2_COARSE_ENTRY_COUNT) {
pageTable = get_or_create_page_table(address,
ARM_MMU_L1_TYPE_COARSE);
pageTableIndex = VADDR_TO_PTENT(address);
}
pos += B_PAGE_SIZE;
}
if (c > 0) {
sPageDirectory[VADDR_TO_PDENT(pos)]
= (uint32)pageTable | ARM_MMU_L1_TYPE_COARSE;
pageTable[pageTableIndex++]
= address | LOADER_MEMORYMAP[i].flags | smallType;
address += B_PAGE_SIZE;
}
}