95 lines
4 KiB
C
95 lines
4 KiB
C
/*********************************************************************************/
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/* Module Name: paging.c */
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/* Project: AurixOS */
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/* */
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/* Copyright (c) 2024-2025 Jozef Nagy */
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/* */
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/* This source is subject to the MIT License. */
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/* See License.txt in the root of this repository. */
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/* All other rights reserved. */
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/* */
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/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR */
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/* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, */
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/* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE */
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/* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER */
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/* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, */
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/* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE */
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/* SOFTWARE. */
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/*********************************************************************************/
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#include <mm/mman.h>
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#include <mm/vmm.h>
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#include <lib/string.h>
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#include <print.h>
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#include <axboot.h>
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#include <stdint.h>
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/* Trimmed down version of */
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/* https://github.com/KevinAlavik/nekonix/blob/main/kernel/src/mm/vmm.c */
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/* Thanks, Kevin <3 */
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static void _map(pagetable *pm, uintptr_t virt, uintptr_t phys, uint64_t flags)
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{
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uint64_t pml1_idx = (virt >> 12) & 0x1ff;
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uint64_t pml2_idx = (virt >> 21) & 0x1ff;
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uint64_t pml3_idx = (virt >> 30) & 0x1ff;
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uint64_t pml4_idx = (virt >> 39) & 0x1ff;
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flags |= VMM_PRESENT;
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if (!(pm->entries[pml4_idx] & 1)) {
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void *pml4 = mem_alloc(PAGE_SIZE);
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memset(pml4, 0, sizeof(pagetable));
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pm->entries[pml4_idx] = (uint64_t)pml4 | VMM_PRESENT | VMM_WRITABLE;
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}
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pagetable *pml3_table = (pagetable *)(pm->entries[pml4_idx] & 0x000FFFFFFFFFF000);
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if (!(pml3_table->entries[pml3_idx] & 1)) {
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void *pml3 = mem_alloc(PAGE_SIZE);
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memset(pml3, 0, sizeof(pagetable));
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pml3_table->entries[pml3_idx] = (uint64_t)pml3 | VMM_PRESENT | VMM_WRITABLE;
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}
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pagetable *pml2_table = (pagetable *)(pml3_table->entries[pml3_idx] & 0x000FFFFFFFFFF000);
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if (!(pml2_table->entries[pml2_idx] & 1)) {
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void *pml2 = mem_alloc(PAGE_SIZE);
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memset(pml2, 0, sizeof(pagetable));
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pml2_table->entries[pml2_idx] = (uint64_t)pml2 | VMM_PRESENT | VMM_WRITABLE;
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}
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pagetable *pml1_table = (pagetable *)(pml2_table->entries[pml2_idx] & 0x000FFFFFFFFFF000);
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if ((pml1_table->entries[pml1_idx] & 1)) {
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debug("_map(): Remapping present page\n");
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}
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pml1_table->entries[pml1_idx] = (phys & 0x000FFFFFFFFFF000) | flags;
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}
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void map_pages(pagetable *pm, uintptr_t virt, uintptr_t phys, size_t size, uint64_t flags)
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{
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for (size_t i = 0; i < ROUND_UP(size, PAGE_SIZE); i += PAGE_SIZE) {
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_map(pm, virt + i, phys + i, flags);
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}
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debug("map_pages(): Mapped 0x%llx-0x%llx -> 0x%llx-0x%llx\n", phys, phys + (size * PAGE_SIZE), virt, virt + (size * PAGE_SIZE));
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}
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void map_page(pagetable *pm, uintptr_t virt, uintptr_t phys, uint64_t flags)
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{
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_map(pm, virt, phys, flags);
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debug("map_page(): Mapped 0x%llx -> 0x%llx\n", phys, virt);
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}
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pagetable *create_pagemap()
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{
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pagetable *pm = (pagetable *)mem_alloc(PAGE_SIZE);
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if (!pm) {
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debug("create_pagemap(): Failed to allocate memory for a new pm.\n");
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return NULL;
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}
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pm = (pagetable *)ROUND_UP((uint64_t)pm, PAGE_SIZE);
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memset(pm, 0, sizeof(pagetable));
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debug("create_pagemap(): Created new pm at 0x%llx\n", (uint64_t)pm);
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return pm;
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}
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