feat: initial paging setup

kernel/mem/vmm.c

@@ -0,0 +1,116 @@
+//
+// Created by rick on 21-02-21.
+//
+
+#include <attributes.h>
+#include <stdbool.h>
+#include <sys/types.h>
+
+#include <myke/mem/vmm.h>
+#include <myke/mem/pm.h>
+#include <myke/libk/libk.h>
+
+#define TABLE_ADDR_MASK 0xFFFFF000
+#define TABLE_ADDR_IMASK ~TABLE_ADDR_MASK
+#define DIRECTORY_SIZE 1024
+
+const uint32_t x = TABLE_ADDR_MASK;
+typedef struct {
+    union {
+        struct {
+            bool present: 1;
+            bool read_write: 1;
+            bool user_mode: 1;
+            bool write_through: 1;
+            bool cache_disabled: 1;
+            bool accessed: 1;
+            char: 1;
+            bool page_size: 1;
+            bool global: 1; // ignored
+            uint8_t avail: 3;
+        } att_packed;
+        uint32_t addr;
+    };
+} att_packed page_directory_entry;
+
+typedef struct {
+    union {
+        struct {
+            bool present: 1;
+            bool read_write: 1;
+            bool user_supervisor: 1;
+            bool write_through: 1;
+            bool cache_disabled: 1;
+            bool accessed: 1;
+            bool dirty: 1;
+            char: 1;
+            bool global: 1;
+            uint8_t available: 3;
+        } att_packed;
+        uint32_t addr;
+    };
+} att_packed page_table_entry;
+
+//#define in_dir(dir, vaddr) ((page_table_entry*)(((page_directory_entry*)((dir)[(vaddr)/4096/1024].addr & TABLE_ADDR_MASK))[(vaddr)/4096%1024]))
+
+#define dir_index(vaddr) (((uint32_t)(vaddr)) / PAGE_SIZE / DIRECTORY_SIZE)
+#define page_index(vaddr) (((uint32_t)(vaddr)) / PAGE_SIZE % DIRECTORY_SIZE)
+
+page_directory_entry boot_paging_directory[DIRECTORY_SIZE] att_aligned(4096);
+page_table_entry boot_primary_table[DIRECTORY_SIZE] att_aligned(4096);
+
+extern page_directory_entry *vmm_get_current_page_directory();
+
+void vmm_assign_page_one(uint32_t paddr, uint32_t vaddr) {
+    page_directory_entry *curr = vmm_get_current_page_directory();
+
+    page_directory_entry *dentry = &curr[dir_index(vaddr)];
+    if (!dentry->present || (dentry->addr & TABLE_ADDR_MASK) == 0) {
+        // todo allocate table
+        k_panics("need to allocate new table");
+    }
+
+    page_table_entry *first_entry = (page_table_entry *) (dentry->addr & TABLE_ADDR_MASK);
+    page_table_entry *pentry = &first_entry[page_index(vaddr)];
+    if (pentry->present) {
+        // todo already present
+        k_panics("virtual address already in use");
+    }
+
+    pentry->addr = (pentry->addr & TABLE_ADDR_IMASK) | paddr;
+    pentry->present = true;
+    pentry->read_write = true;
+}
+
+void vmm_unassign_page_one(uint32_t vaddr) {
+    page_directory_entry *curr = vmm_get_current_page_directory();
+
+    page_directory_entry *dentry = &curr[dir_index(vaddr)];
+    if (!dentry->present || (dentry->addr & TABLE_ADDR_MASK) == 0) {
+        // todo allocate table
+        k_panics("need to allocate new table");
+    }
+
+    page_table_entry *first_entry = (page_table_entry *) (dentry->addr & TABLE_ADDR_MASK);
+    page_table_entry *pentry = &first_entry[page_index(vaddr)];
+    if (!pentry->present) {
+        // todo already present
+        k_panics("virtual address not in use");
+    }
+
+    pentry->present = false;
+    pentry->read_write = false;
+    pentry->addr = pentry->addr & TABLE_ADDR_IMASK;
+}
+
+void vmm_assign_page(void *paddr, void *vaddr, size_t number_of_pages) {
+    for (size_t i = 0; i < number_of_pages; ++i) {
+        vmm_assign_page_one(((uint32_t) paddr) + PAGE_SIZE * i, ((uint32_t) vaddr) + PAGE_SIZE * i);
+    }
+}
+
+void vmm_unassign_page(void *vaddr, size_t number_of_pages) {
+    for (size_t i = 0; i < number_of_pages; ++i) {
+        vmm_unassign_page_one(((uint32_t) vaddr) + PAGE_SIZE * i);
+    }
+}