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Kernel/aarch64: Set up quickmap infrastructure in initial page tables
With this change the quickmap related functions in MemoryManager actually work. :^)
This commit is contained in:
parent
a62732ee2f
commit
96f73c9289
Notes:
sideshowbarker
2024-07-17 06:30:06 +09:00
Author: https://github.com/FireFox317 Commit: https://github.com/SerenityOS/serenity/commit/96f73c9289 Pull-request: https://github.com/SerenityOS/serenity/pull/15309 Reviewed-by: https://github.com/bgianfo Reviewed-by: https://github.com/bugreport0 Reviewed-by: https://github.com/nico ✅
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@ -13,7 +13,9 @@
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#include <Kernel/Arch/aarch64/RPi/MMIO.h>
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#include <Kernel/Arch/aarch64/RPi/UART.h>
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#include <Kernel/Arch/aarch64/Registers.h>
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#include <Kernel/BootInfo.h>
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#include <Kernel/Panic.h>
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#include <Kernel/Sections.h>
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// Documentation here for Aarch64 Address Translations
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// https://documentation-service.arm.com/static/5efa1d23dbdee951c1ccdec5?token=
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@ -79,48 +81,59 @@ private:
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};
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}
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static u64* insert_page_table(PageBumpAllocator& allocator, u64* page_table, VirtualAddress virtual_addr)
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{
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// Each level has 9 bits (512 entries)
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u64 level0_idx = (virtual_addr.get() >> 39) & 0x1FF;
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u64 level1_idx = (virtual_addr.get() >> 30) & 0x1FF;
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u64 level2_idx = (virtual_addr.get() >> 21) & 0x1FF;
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u64* level1_table = page_table;
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if (level1_table[level0_idx] == 0) {
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level1_table[level0_idx] = (FlatPtr)allocator.take_page();
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level1_table[level0_idx] |= TABLE_DESCRIPTOR;
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}
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u64* level2_table = descriptor_to_pointer(level1_table[level0_idx]);
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if (level2_table[level1_idx] == 0) {
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level2_table[level1_idx] = (FlatPtr)allocator.take_page();
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level2_table[level1_idx] |= TABLE_DESCRIPTOR;
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}
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u64* level3_table = descriptor_to_pointer(level2_table[level1_idx]);
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if (level3_table[level2_idx] == 0) {
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level3_table[level2_idx] = (FlatPtr)allocator.take_page();
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level3_table[level2_idx] |= TABLE_DESCRIPTOR;
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}
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return descriptor_to_pointer(level3_table[level2_idx]);
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}
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static void insert_identity_entries_for_physical_memory_range(PageBumpAllocator& allocator, u64* page_table, FlatPtr start, FlatPtr end, u64 flags)
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{
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// Not very efficient, but simple and it works.
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for (FlatPtr addr = start; addr < end; addr += GRANULE_SIZE) {
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// Each level has 9 bits (512 entries)
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u64 level0_idx = (addr >> 39) & 0x1FF;
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u64 level1_idx = (addr >> 30) & 0x1FF;
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u64 level2_idx = (addr >> 21) & 0x1FF;
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u64* level4_table = insert_page_table(allocator, page_table, VirtualAddress { addr });
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u64 level3_idx = (addr >> 12) & 0x1FF;
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u64* level1_table = page_table;
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if (level1_table[level0_idx] == 0) {
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level1_table[level0_idx] = (FlatPtr)allocator.take_page();
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level1_table[level0_idx] |= TABLE_DESCRIPTOR;
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}
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u64* level2_table = descriptor_to_pointer(level1_table[level0_idx]);
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if (level2_table[level1_idx] == 0) {
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level2_table[level1_idx] = (FlatPtr)allocator.take_page();
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level2_table[level1_idx] |= TABLE_DESCRIPTOR;
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}
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u64* level3_table = descriptor_to_pointer(level2_table[level1_idx]);
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if (level3_table[level2_idx] == 0) {
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level3_table[level2_idx] = (FlatPtr)allocator.take_page();
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level3_table[level2_idx] |= TABLE_DESCRIPTOR;
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}
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u64* level4_table = descriptor_to_pointer(level3_table[level2_idx]);
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u64* l4_entry = &level4_table[level3_idx];
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*l4_entry = addr;
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*l4_entry |= flags;
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}
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}
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static void build_identity_map(PageBumpAllocator& allocator)
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static void setup_quickmap_page_table(PageBumpAllocator& allocator, u64* root_table)
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{
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u64* level1_table = allocator.take_page();
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// FIXME: Rename boot_pd_kernel_pt1023 to quickmap_page_table
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// FIXME: Rename KERNEL_PT1024_BASE to quickmap_page_table_address
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boot_pd_kernel_pt1023 = (PageTableEntry*)insert_page_table(allocator, root_table, VirtualAddress { KERNEL_PT1024_BASE });
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}
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static void build_identity_map(PageBumpAllocator& allocator, u64* root_table)
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{
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u64 normal_memory_flags = ACCESS_FLAG | PAGE_DESCRIPTOR | INNER_SHAREABLE | NORMAL_MEMORY;
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u64 device_memory_flags = ACCESS_FLAG | PAGE_DESCRIPTOR | OUTER_SHAREABLE | DEVICE_MEMORY;
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@ -128,8 +141,8 @@ static void build_identity_map(PageBumpAllocator& allocator)
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FlatPtr start_of_range = ((FlatPtr)start_of_kernel_image & ~(FlatPtr)0x1fffff);
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FlatPtr end_of_range = ((FlatPtr)end_of_kernel_image & ~(FlatPtr)0x1fffff) + 0x200000 - 1;
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insert_identity_entries_for_physical_memory_range(allocator, level1_table, start_of_range, end_of_range, normal_memory_flags);
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insert_identity_entries_for_physical_memory_range(allocator, level1_table, RPi::MMIO::the().peripheral_base_address(), RPi::MMIO::the().peripheral_end_address(), device_memory_flags);
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insert_identity_entries_for_physical_memory_range(allocator, root_table, start_of_range, end_of_range, normal_memory_flags);
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insert_identity_entries_for_physical_memory_range(allocator, root_table, RPi::MMIO::the().peripheral_base_address(), RPi::MMIO::the().peripheral_end_address(), device_memory_flags);
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}
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static void switch_to_page_table(u8* page_table)
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@ -177,8 +190,15 @@ static void activate_mmu()
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void init_page_tables()
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{
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// We currently identity map the physical memory, so the offset is 0.
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physical_to_virtual_offset = 0;
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kernel_mapping_base = 0;
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PageBumpAllocator allocator((u64*)page_tables_phys_start, (u64*)page_tables_phys_end);
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build_identity_map(allocator);
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auto root_table = allocator.take_page();
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build_identity_map(allocator, root_table);
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setup_quickmap_page_table(allocator, root_table);
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switch_to_page_table(page_tables_phys_start);
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activate_mmu();
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}
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