190 lines
7.2 KiB
C
190 lines
7.2 KiB
C
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#include "memory.h"
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#include "paging_internal.h"
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#include "../runtime/panic_assert.h"
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#include "string.h"
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// some learning:
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// https://forum.osdev.org/viewtopic.php?f=1&t=51392 (Confirmative question about 4-level and 5-level paging)
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void paging_map_Page(uint64_t physical, uint64_t virtual, int pageCount, int protectionFlags) {
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assert(physical % SYSTEM_PAGE_SIZE == 0 && "Physical address not page-aligned");
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assert(virtual % SYSTEM_PAGE_SIZE == 0 && "Virtual address not page-aligned");
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while (pageCount--) {
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// PML4E index pointing to a PML3 table (Page-Directory-Pointer Table)
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uint64_t *table = paging_PML4Table;
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uint64_t i = takeBitfield(virtual, 47, 39);
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if ((table[i] & PML_PRESENT) == 0) // allocate a new page as PML3 table
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table[i] = paging_physical_AllocateOneFrame() | PML_PRESENT | PML_WRITEABLE;
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// PML3E(PDPTE) index pointing to a PML2 table (Page-Directory)
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table = (uint64_t *)(table[i] & PML_ADDR_MASK);
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i = takeBitfield(virtual, 38, 30);
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if ((table[i] & PML_PRESENT) == 0) // allocate page as page directory
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table[i] = paging_physical_AllocateOneFrame() | PML_PRESENT | PML_WRITEABLE;
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// PML2E(PD) index pointing to a PML1 table (Page Table)
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table = (uint64_t *)(table[i] & PML_ADDR_MASK);
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i = takeBitfield(virtual, 29, 21);
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if ((table[i] & PML_PRESENT) == 0) // allocate page as page table
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table[i] = paging_physical_AllocateOneFrame() | PML_PRESENT | PML_WRITEABLE;
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// Finally, the page table.
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table = (uint64_t *)(table[i] & PML_ADDR_MASK);
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i = takeBitfield(virtual, 20, 12);
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table[i] = physical | PML_PRESENT |
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((protectionFlags & MAP_PROT_WRITE) ? PML_WRITEABLE : 0) |
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((paging_SupportExecuteDisable && !(protectionFlags & MAP_PROT_EXEC)) ? PML_EXECUTE_DISABLE : 0);
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flush_tlb_single(virtual);
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physical += SYSTEM_PAGE_SIZE;
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virtual += SYSTEM_PAGE_SIZE;
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}
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}
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void paging_map_Page2M(uint64_t physical, uint64_t virtual, int pageCount, int protectionFlags) {
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assert(physical % SYSTEM_PAGE_2M_SIZE == 0 && "Physical address not page-aligned");
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assert(virtual % SYSTEM_PAGE_2M_SIZE == 0 && "Virtual address not page-aligned");
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while (pageCount--) {
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// PML4E index pointing to a PML3 table (Page-Directory-Pointer Table)
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uint64_t *table = paging_PML4Table;
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uint64_t i = takeBitfield(virtual, 47, 39);
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if ((table[i] & PML_PRESENT) == 0) // allocate a new page as PML3 table
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table[i] = paging_physical_AllocateOneFrame() | PML_PRESENT | PML_WRITEABLE;
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// PML3E(PDPTE) index pointing to a PML2 table (Page-Directory)
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table = (uint64_t *)(table[i] & PML_ADDR_MASK);
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i = takeBitfield(virtual, 38, 30);
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if ((table[i] & PML_PRESENT) == 0) // allocate page as page directory
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table[i] = paging_physical_AllocateOneFrame() | PML_PRESENT | PML_WRITEABLE;
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// PML2E(PD) index pointing to a PML1 table (Page Table)
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table = (uint64_t *)(table[i] & PML_ADDR_MASK);
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i = takeBitfield(virtual, 29, 21);
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if ((table[i] & PML_PRESENT) != 0 && (table[i] & PML_PAGE_SIZE) == 0) // deallocate the page if present
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paging_physical_FreeFrame(table[i] & PML_ADDR_MASK, 1);
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// 2MB pages in Page Tables
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table[i] = physical | PML_PRESENT | PML_PAGE_SIZE |
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((protectionFlags & MAP_PROT_WRITE) ? PML_WRITEABLE : 0) |
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((paging_SupportExecuteDisable && !(protectionFlags & MAP_PROT_EXEC)) ? PML_EXECUTE_DISABLE : 0);
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flush_tlb_single(virtual);
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physical += SYSTEM_PAGE_2M_SIZE;
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virtual += SYSTEM_PAGE_2M_SIZE;
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}
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}
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void paging_map_Page1G(uint64_t physical, uint64_t virtual, int pageCount, int protectionFlags) {
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assert(physical % SYSTEM_PAGE_1G_SIZE == 0 && "Physical address not page-aligned");
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assert(virtual % SYSTEM_PAGE_1G_SIZE == 0 && "Virtual address not page-aligned");
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while (pageCount--) {
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// PML4E index pointing to a PML3 table (Page-Directory-Pointer Table)
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uint64_t *table = paging_PML4Table;
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uint64_t i = takeBitfield(virtual, 47, 39);
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if ((table[i] & PML_PRESENT) == 0) // allocate a new page as PML3 table
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table[i] = paging_physical_AllocateOneFrame() | PML_PRESENT | PML_WRITEABLE;
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// PML3E(PDPTE) index pointing to a PML2 table (Page-Directory)
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table = (uint64_t *)(table[i] & PML_ADDR_MASK);
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i = takeBitfield(virtual, 38, 30);
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if ((table[i] & PML_PRESENT) != 0 && (table[i] & PML_PAGE_SIZE) == 0) // deallocate the page if present
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paging_physical_FreeFrame(table[i] & PML_ADDR_MASK, 1);
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// 1GB pages in Page Directories
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table[i] = physical | PML_PRESENT | PML_PAGE_SIZE |
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((protectionFlags & MAP_PROT_WRITE) ? PML_WRITEABLE : 0) |
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((paging_SupportExecuteDisable && !(protectionFlags & MAP_PROT_EXEC)) ? PML_EXECUTE_DISABLE : 0);
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flush_tlb_single(virtual);
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physical += SYSTEM_PAGE_1G_SIZE;
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virtual += SYSTEM_PAGE_1G_SIZE;
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}
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}
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void paging_map_PageAllocated(uint64_t virtual, int pageCount, int protectionFlags) {
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assert(virtual % SYSTEM_PAGE_SIZE == 0 && "Virtual address not page-aligned");
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// skip the first 1M
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int i = 1024 / 4 / BITMAP_BITS;
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while (pageCount--) {
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uint64_t freshPage = 0;
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// this code is in sync with paging_physical.c, paging_physical_AllocateOneFrame, so you have to modify both
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for (; i < paging_EndPhysicalPage / BITMAP_BITS; i++)
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if (paging_physical_Bitmap[i] != ~0ull)
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for (int j = 0; j < BITMAP_BITS; j++)
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if ((paging_physical_Bitmap[i] & (1ull << j)) == 0) {
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paging_physical_Bitmap[i] |= (1ull << j);
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freshPage = (((uint64_t)i) * BITMAP_BITS + j) * SYSTEM_PAGE_SIZE;
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memset((void *)freshPage, 0, SYSTEM_PAGE_SIZE);
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}
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paging_map_Page(freshPage, virtual, 1, protectionFlags);
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virtual += SYSTEM_PAGE_SIZE;
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}
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}
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void paging_map_PageAllocated2M(uint64_t virtual, int pageCount, int protectionFlags) {
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assert(pageCount > HELOS_BUFFER_SIZE / SYSTEM_PAGE_2M_SIZE * 8 && "helos_Buffer unable to hold all pointers");
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assert(virtual % SYSTEM_PAGE_2M_SIZE == 0 && "Virtual address not page-aligned");
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uint64_t *buf = (uint64_t *)Buffer;
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int allocated = paging_physical_AllocateFrames2M(pageCount, buf);
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for (int i = 0; i < allocated; i++)
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paging_map_Page2M(buf[i], virtual + SYSTEM_PAGE_2M_SIZE * i, 1, protectionFlags);
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}
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void paging_map_FreeAllocated(uint64_t virtual, uint64_t end) {
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assert(virtual % SYSTEM_PAGE_SIZE == 0 && "Virtual address not page-aligned");
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while (virtual < end) {
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uint64_t *table = paging_PML4Table;
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uint64_t i = takeBitfield(virtual, 47, 39);
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if ((table[i] & PML_PRESENT) == 0)
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goto loop_end;
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table = (uint64_t *)(table[i] & PML_ADDR_MASK);
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i = takeBitfield(virtual, 38, 30);
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if ((table[i] & PML_PRESENT) == 0)
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goto loop_end;
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if (table[i] & PML_PAGE_SIZE) { // 1G mapping
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paging_physical_FreeFrame(table[i] & PML_ADDR_MASK_1G, 512 * 512);
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table[i] = 0;
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virtual += SYSTEM_PAGE_1G_SIZE;
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continue;
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}
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table = (uint64_t *)(table[i] & PML_ADDR_MASK);
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i = takeBitfield(virtual, 29, 21);
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if ((table[i] & PML_PRESENT) == 0)
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goto loop_end;
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if (table[i] & PML_PAGE_SIZE) { // 2M mapping
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paging_physical_FreeFrame(table[i] & PML_ADDR_MASK_2M, 512);
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table[i] = 0;
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virtual += SYSTEM_PAGE_2M_SIZE;
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continue;
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}
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table = (uint64_t *)(table[i] & PML_ADDR_MASK);
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i = takeBitfield(virtual, 20, 12);
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if (table[i] & PML_PRESENT) {
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paging_physical_FreeFrame(table[i] & PML_ADDR_MASK, 1);
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table[i] = 0;
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}
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loop_end:
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virtual += SYSTEM_PAGE_SIZE;
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}
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}
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