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kernel/arm: don't require identity mapping of initial page tables

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Remove the dependency on identity mapping for the initial page tables
used in MapEarly / _EarlyQuery.

The initial page tables have to satisfy the following conditions instead:
* the inital page tables shall be allocated in the same region as the initial page directory
* this region shall be mapped contiguously
* the page tables shall be mapped at a higher address than the page directory

Change-Id: I34854ef93826aa48f5d90582b52905e553f3d275
Reviewed-on: https://review.haiku-os.org/c/haiku/+/4857
Tested-by: Commit checker robot <no-reply+buildbot@haiku-os.org>
Reviewed-by: Adrien Destugues <pulkomandy@gmail.com>
This commit is contained in:
David Karoly 2022-01-11 17:16:36 +01:00 committed by Alex von Gluck IV
parent dc3e1761e6
commit 9103470bd3
1 changed files with 23 additions and 13 deletions
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36
src/system/kernel/arch/arm/paging/32bit/ARMPagingMethod32Bit.cpp
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@ -361,13 +361,15 @@ ARMPagingMethod32Bit::CreateTranslationMap(bool kernel, VMTranslationMap** _map)
}
static phys_addr_t
get_free_pgtable(kernel_args* args)
static void
get_free_pgtable(kernel_args* args, phys_addr_t* phys_addr, addr_t* virt_addr)
{
phys_addr_t phys = args->arch_args.phys_pgdir + args->arch_args.next_pagetable;
//addr_t virt = args->arch_args.vir_pgdir + args->arch_args.next_pagetable;
addr_t virt = args->arch_args.vir_pgdir + args->arch_args.next_pagetable;
args->arch_args.next_pagetable += ARM_MMU_L2_COARSE_TABLE_SIZE;
return phys;
*phys_addr = phys;
*virt_addr = virt;
}
status_t
@ -378,24 +380,28 @@ ARMPagingMethod32Bit::MapEarly(kernel_args* args, addr_t virtualAddress,
// check to see if a page table exists for this range
int index = VADDR_TO_PDENT(virtualAddress);
if ((fKernelVirtualPageDirectory[index] & ARM_PDE_TYPE_MASK) == 0) {
phys_addr_t pgtable;
phys_addr_t pgtable_phys;
addr_t pgtable_virt;
page_directory_entry *e;
// we need to allocate a pgtable
pgtable = get_free_pgtable(args);
get_free_pgtable(args, &pgtable_phys, &pgtable_virt);
TRACE("ARMPagingMethod32Bit::MapEarly(): asked for free page for "
"pgtable. %#" B_PRIxPHYSADDR "\n", pgtable);
"pgtable. phys=%#" B_PRIxPHYSADDR ", virt=%#" B_PRIxADDR "\n",
pgtable_phys, pgtable_virt);
// put it in the pgdir
e = &fKernelVirtualPageDirectory[index];
PutPageTableInPageDir(e, pgtable, attributes);
PutPageTableInPageDir(e, pgtable_phys, attributes);
// zero it out in it's new mapping
memset((void*)pgtable, 0, B_PAGE_SIZE);
memset((void*)pgtable_virt, 0, B_PAGE_SIZE);
}
page_table_entry* ptEntry = (page_table_entry*)
(fKernelVirtualPageDirectory[index] & ARM_PDE_ADDRESS_MASK);
phys_addr_t ptEntryPhys = fKernelVirtualPageDirectory[index] & ARM_PDE_ADDRESS_MASK;
addr_t ptEntryVirt = ptEntryPhys - args->arch_args.phys_pgdir + args->arch_args.vir_pgdir;
page_table_entry* ptEntry = (page_table_entry*)ptEntryVirt;
ptEntry += VADDR_TO_PTENT(virtualAddress);
ASSERT_PRINT(
@ -566,8 +572,12 @@ ARMPagingMethod32Bit::_EarlyQuery(addr_t virtualAddress,
return B_ERROR;
}
page_table_entry* entry = (page_table_entry*)
(method->KernelVirtualPageDirectory()[index] & ARM_PDE_ADDRESS_MASK);
phys_addr_t ptEntryPhys = method->KernelVirtualPageDirectory()[index] & ARM_PDE_ADDRESS_MASK;
addr_t ptEntryVirt = ptEntryPhys -
(uint32_t)method->KernelPhysicalPageDirectory() +
(uint32_t)method->KernelVirtualPageDirectory();
page_table_entry* entry = (page_table_entry*)ptEntryVirt;
entry += VADDR_TO_PTENT(virtualAddress);
if ((*entry & ARM_PTE_TYPE_MASK) == 0) {