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Made the page table allocation/filling mechanism a bit more flexible and less error prone.

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Also, freeing regions is now supported (but still only the last allocated region can be
freed, as that's currently good enough).


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@14366 a95241bf-73f2-0310-859d-f6bbb57e9c96
This commit is contained in:
Axel Dörfler 2005-10-13 13:37:18 +00:00
parent a26988784a
commit 0eecdd8334
1 changed files with 36 additions and 15 deletions
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51
src/system/boot/platform/bios_ia32/mmu.cpp
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@ -59,6 +59,7 @@ struct extended_memory {
static const uint32 kDefaultPageTableFlags = 0x07; // present, user, R/W
static const size_t kMaxKernelSize = 0x100000; // 1 MB for the kernel
static const uint32 kPageTableRegionEnd = 0xa0000;
// working page directory and page table
static uint32 *sPageDirectory = 0;
@ -69,6 +70,8 @@ static addr_t sNextPhysicalAddress = 0x100000;
static addr_t sNextVirtualAddress = KERNEL_BASE + kMaxKernelSize;
static addr_t sMaxVirtualAddress = KERNEL_BASE + 0x400000;
static addr_t sNextPageTableAddress = 0x90000;
static addr_t
get_next_virtual_address(size_t size)
@ -104,6 +107,18 @@ get_next_physical_page()
}
static uint32 *
get_next_page_table()
{
addr_t address = sNextPageTableAddress;
if (address >= kPageTableRegionEnd)
return (uint32 *)get_next_physical_page();
sNextPageTableAddress += B_PAGE_SIZE;
return (uint32 *)address;
}
/** Adds a new page table for the specified base address and makes
* it current, ie. sets sPageTable to point to the new table.
*/
@ -111,8 +126,10 @@ get_next_physical_page()
static void
add_page_table(addr_t base)
{
TRACE(("add_page_table(base = %p)\n", (void *)base));
// Get new page table and clear it out
sPageTable = (uint32 *)get_next_physical_page();
sPageTable = get_next_page_table();
if (sPageTable > (uint32 *)(8 * 1024 * 1024))
panic("tried to add page table beyond the indentity mapped 8 MB region\n");
@ -134,7 +151,10 @@ unmap_page(addr_t virtualAddress)
if (virtualAddress < KERNEL_BASE)
panic("unmap_page: asked to unmap invalid page %p!\n", (void *)virtualAddress);
sPageTable[(virtualAddress % (B_PAGE_SIZE * 1024)) / B_PAGE_SIZE] = 0;
// unmap the page from the correct page table
uint32 *pageTable = (uint32 *)(sPageDirectory[virtualAddress
/ (B_PAGE_SIZE * 1024)] & 0xfffff000);
pageTable[(virtualAddress % (B_PAGE_SIZE * 1024)) / B_PAGE_SIZE] = 0;
asm volatile("invlpg (%0)" : : "r" (virtualAddress));
}
@ -166,9 +186,10 @@ map_page(addr_t virtualAddress, addr_t physicalAddress, uint32 flags)
physicalAddress &= ~(B_PAGE_SIZE - 1);
TRACE(("paddr 0x%lx @ index %ld\n", physicalAddress,
(virtualAddress % (B_PAGE_SIZE * 1024)) / B_PAGE_SIZE));
sPageTable[(virtualAddress % (B_PAGE_SIZE * 1024)) / B_PAGE_SIZE] = physicalAddress | flags;
// map the page to the correct page table
uint32 *pageTable = (uint32 *)(sPageDirectory[virtualAddress
/ (B_PAGE_SIZE * 1024)] & 0xfffff000);
pageTable[(virtualAddress % (B_PAGE_SIZE * 1024)) / B_PAGE_SIZE] = physicalAddress | flags;
asm volatile("invlpg (%0)" : : "r" (virtualAddress));
}
@ -245,23 +266,23 @@ init_page_directory(void)
// physical and virtual address are the same.
// These page tables won't be taken over into the kernel.
// make a pagetable at this random spot
uint32 *pgtable = (uint32 *)0x91000;
// make the first page table at the first free spot
uint32 *pageTable = get_next_page_table();;
for (int32 i = 0; i < 1024; i++) {
pgtable[i] = (i * 0x1000) | kDefaultPageFlags;
pageTable[i] = (i * 0x1000) | kDefaultPageFlags;
}
sPageDirectory[0] = (uint32)pgtable | kDefaultPageFlags;
sPageDirectory[0] = (uint32)pageTable | kDefaultPageFlags;
// make another pagetable at this random spot
pgtable = (uint32 *)0x92000;
// make the second page table
pageTable = get_next_page_table();;
for (int32 i = 0; i < 1024; i++) {
pgtable[i] = (i * 0x1000 + 0x400000) | kDefaultPageFlags;
pageTable[i] = (i * 0x1000 + 0x400000) | kDefaultPageFlags;
}
sPageDirectory[1] = (uint32)pgtable | kDefaultPageFlags;
sPageDirectory[1] = (uint32)pageTable | kDefaultPageFlags;
gKernelArgs.arch_args.num_pgtables = 0;
add_page_table(KERNEL_BASE);
@ -587,8 +608,8 @@ platform_allocate_region(void **_address, size_t size, uint8 protection)
extern "C" status_t
platform_free_region(void *address, size_t size)
{
puts(__FUNCTION__);
return B_ERROR;
mmu_free(address, size);
return B_OK;
}