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Added support to map more than 4 MB in the kernel space. This became necessary 

to be able to have more than 1280x1024x8 resolutions. The best solution, however,
would be to map the graphics memory outside of the kernel space, anyway.


git-svn-id: file:///srv/svn/repos/haiku/trunk/current@9537 a95241bf-73f2-0310-859d-f6bbb57e9c96
This commit is contained in:
Axel Dörfler 2004-10-27 16:44:04 +00:00
parent 1b50789288
commit 48ac51f886
1 changed files with 35 additions and 12 deletions
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47
src/kernel/boot/platform/bios_ia32/mmu.cpp
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@ -102,6 +102,28 @@ get_next_physical_page()
}
/** Adds a new page table for the specified base address and makes
* it current, ie. sets sPageTable to point to the new table.
*/
static void
add_page_table(addr_t base)
{
// Get new page table and clear it out
sPageTable = (uint32 *)get_next_physical_page();
if (sPageTable > (uint32 *)(8 * 1024 * 1024))
panic("tried to add page table beyond the indentity mapped 8 MB region\n");
gKernelArgs.arch_args.pgtables[gKernelArgs.arch_args.num_pgtables++] = (uint32)sPageTable;
for (int32 i = 0; i < 1024; i++)
sPageTable[i] = 0;
// put the new page table into the page directory
sPageDirectory[base/(4*1024*1024)] = (uint32)sPageTable | kDefaultPageFlags;
}
/** Creates an entry to map the specified virtualAddress to the given
* physicalAddress.
* Note, it can only map the 4 meg region right after KERNEL_BASE; this
@ -114,9 +136,19 @@ map_page(addr_t virtualAddress, addr_t physicalAddress, uint32 flags)
{
TRACE(("map_page: vaddr 0x%lx, paddr 0x%lx\n", virtualAddress, physicalAddress));
if (virtualAddress < KERNEL_BASE || virtualAddress >= sMaxVirtualAddress)
if (virtualAddress < KERNEL_BASE)
panic("map_page: asked to map invalid page %p!\n", (void *)virtualAddress);
if (virtualAddress >= sMaxVirtualAddress) {
// we need to add a new page table
add_page_table(sMaxVirtualAddress);
sMaxVirtualAddress += B_PAGE_SIZE * 1024;
if (virtualAddress >= sMaxVirtualAddress)
panic("map_page: asked to map a page to %p\n", (void *)virtualAddress);
}
physicalAddress &= ~(B_PAGE_SIZE - 1);
TRACE(("paddr 0x%lx @ index %ld\n", physicalAddress,
@ -214,17 +246,8 @@ init_page_directory()
sPageDirectory[1] = (uint32)pgtable | kDefaultPageFlags;
// Get new page table and clear it out
sPageTable = (uint32 *)get_next_physical_page();
gKernelArgs.arch_args.pgtables[0] = (uint32)sPageTable;
gKernelArgs.arch_args.num_pgtables = 1;
for (int32 i = 0; i < 1024; i++)
sPageTable[i] = 0;
// put the new page table into the page directory
// this maps the kernel at KERNEL_BASE
sPageDirectory[KERNEL_BASE/(4*1024*1024)] = (uint32)sPageTable | kDefaultPageFlags;
gKernelArgs.arch_args.num_pgtables = 0;
add_page_table(KERNEL_BASE);
// switch to the new pgdir and enable paging
asm("movl %0, %%eax;"