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-rw-r--r--src/kernel/mem/paging.c203
1 files changed, 0 insertions, 203 deletions
diff --git a/src/kernel/mem/paging.c b/src/kernel/mem/paging.c
deleted file mode 100644
index 0527f06..0000000
--- a/src/kernel/mem/paging.c
+++ /dev/null
@@ -1,203 +0,0 @@
-#include "paging.h"
-#include <bitset.h>
-#include <stdlib_common.h>
-#include <core/monitor.h>
-#include "mem.h"
-#include "seg.h"
-#include <core/sys.h>
-#include <task/task.h>
-
-static struct bitset frames;
-
-struct page_directory *kernel_pagedir, *current_pagedir;
-
-/************************** PHYSICAL MEMORY ALLOCATION ************************/
-
-/* Allocates a page of physical memory. */
-uint32_t frame_alloc() {
- uint32_t free = bitset_firstFree(&frames);
- if (free == (uint32_t) -1) {
- PANIC("No more frames to allocate, system is out of memory!");
- }
- bitset_set(&frames, free);
- return free;
-}
-
-void frame_free(uint32_t id) {
- bitset_clear(&frames, id);
-}
-
-/************************* PAGING INITIALIZATION *****************************/
-
-/* This function creates the kernel page directory. It must be called before the GDT is loaded.
- It maps 0xC0000000+ (k_highhalf_addr) to the corresponding physical kernel code, but it also maps
- 0x00000000+ to that code because with the false GDT we set up in loader_.asm,
- the code will be looked for at the beginning of the memory. Only when the real GDT is loaded
- we can de-allocate pages at 0x00000000 ; this is done by paging_cleanup. */
-void paging_init(size_t totalRam) {
- uint32_t i;
-
- frames.size = totalRam / 0x1000;
- frames.bits = ksbrk(INDEX_FROM_BIT(frames.size));
-
- kernel_pagedir = ksbrk(sizeof(struct page_directory));
- kernel_pagedir->mappedSegs = 0;
- kernel_pagedir->tablesPhysical = kmalloc_page(&kernel_pagedir->physicalAddr);
- for (i = 0; i < 1024; i++) {
- kernel_pagedir->tables[i] = 0;
- kernel_pagedir->tablesPhysical[i] = 0;
- }
-
- for (i = K_HIGHHALF_ADDR; i < mem_placementAddr; i += 0x1000) {
- page_map(pagedir_getPage(kernel_pagedir, i, 1), frame_alloc(), 0, 0);
- }
- for (i = 0; i < (mem_placementAddr - K_HIGHHALF_ADDR) / 0x100000; i++) {
- kernel_pagedir->tablesPhysical[i] = kernel_pagedir->tablesPhysical[i + FIRST_KERNEL_PAGETABLE];
- kernel_pagedir->tables[i] = kernel_pagedir->tables[i + FIRST_KERNEL_PAGETABLE];
- }
-
- monitor_write("{PD: ");
- monitor_writeHex(kernel_pagedir->physicalAddr);
- pagedir_switch(kernel_pagedir);
- monitor_write("} [Paging] ");
-}
-
-/* De-allocates pages at 0x00000000 where kernel code was read from with the GDT from loader_.asm. */
-void paging_cleanup() {
- size_t i;
- for (i = 0; i < (mem_placementAddr - K_HIGHHALF_ADDR) / 0x100000; i++) {
- kernel_pagedir->tablesPhysical[i] = 0;
- kernel_pagedir->tables[i] = 0;
- }
- monitor_write("[PD Cleanup] ");
-}
-
-/************************* PAGING EVERYDAY USE *****************************/
-
-/* Switch to a page directory. Can be done if we are sure not to be interrupted by a task switch.
- Example use for cross-memory space writing in linker/elf.c */
-void pagedir_switch(struct page_directory *pd) {
- current_pagedir = pd;
- asm volatile("mov %0, %%cr3" : : "r"(pd->physicalAddr));
- uint32_t cr0;
- asm volatile("mov %%cr0, %0" : "=r"(cr0));
- cr0 |= 0x80000000;
- asm volatile("mov %0, %%cr0" : : "r"(cr0));
-}
-
-/* Creates a new page directory for a process, and maps the kernel page tables on it. */
-struct page_directory *pagedir_new() {
- uint32_t i;
-
- struct page_directory *pd = kmalloc(sizeof(struct page_directory));
- pd->tablesPhysical = kmalloc_page(&pd->physicalAddr);
- pd->mappedSegs = 0;
-
- for (i = 0; i < 1024; i++) {
- pd->tables[i] = 0; pd->tablesPhysical[i] = 0;
- }
-
- for (i = FIRST_KERNEL_PAGETABLE; i < 1024; i++) {
- pd->tables[i] = kernel_pagedir->tables[i];
- pd->tablesPhysical[i] = kernel_pagedir->tablesPhysical[i];
- }
-
- return pd;
-}
-
-/* Deletes a page directory, cleaning it up. */
-void pagedir_delete(struct page_directory *pd) {
- uint32_t i;
- //Unmap segments
- while (pd->mappedSegs != 0) seg_unmap(pd->mappedSegs);
- //Cleanup page tables
- for (i = 0; i < FIRST_KERNEL_PAGETABLE; i++) {
- kfree_page(pd->tables[i]);
- }
- kfree_page(pd->tablesPhysical);
- kfree(pd);
-}
-
-/* Handle a paging fault. First, looks for the corresponding segment.
- If the segment was found and it handles the fault, return normally.
- Else, display informatinos and return an error. */
-uint32_t paging_fault(struct registers *regs) {
- size_t addr;
- struct segment_map *seg = 0;
- asm volatile("mov %%cr2, %0" : "=r"(addr));
-
- seg = current_pagedir->mappedSegs;
- while (seg) {
- if (seg->start <= addr && seg->start + seg->len > addr) break;
- seg = seg->next;
- }
-
- if (seg != 0) {
- if (seg->seg->handle_fault(seg, addr, (regs->err_code & 0x2) && (regs->eip < K_HIGHHALF_ADDR)) != 0) seg = 0;
- }
-
- if (seg == 0) {
- NL; WHERE; monitor_write("Unhandled Page Fault\t");
- monitor_write("cr2:"); monitor_writeHex(addr);
- NL; TAB;
- if (regs->err_code & 0x1) monitor_write("present"); TAB;
- if (regs->err_code & 0x2) monitor_write("write"); TAB;
- if (regs->err_code & 0x4) monitor_write("user"); TAB;
- if (regs->err_code & 0x8) monitor_write("rsvd"); TAB;
- if (regs->err_code & 0x10) monitor_write("opfetch");
- return 1;
- }
- return 0;
-}
-
-/* Gets the corresponding page in a page directory for a given address.
- If make is set, the necessary page table can be created.
- Can return 0 if make is not set. */
-struct page *pagedir_getPage(struct page_directory *pd, uint32_t address, int make) {
- address /= 0x1000;
- uint32_t table_idx = address / 1024;
-
- if (pd->tables[table_idx]) {
- return &pd->tables[table_idx]->pages[address % 1024];
- } else if (make) {
- pd->tables[table_idx] = kmalloc_page(pd->tablesPhysical + table_idx);
-
- memset((uint8_t*)pd->tables[table_idx], 0, 0x1000);
- pd->tablesPhysical[table_idx] |= 0x07;
-
- if (table_idx >= FIRST_KERNEL_PAGETABLE) {
- tasking_updateKernelPagetable(table_idx, pd->tables[table_idx], pd->tablesPhysical[table_idx]);
- }
-
- return &pd->tables[table_idx]->pages[address % 1024];
- } else {
- return 0;
- }
-}
-
-/* Modifies a page structure so that it is mapped to a frame. */
-void page_map(struct page *page, uint32_t frame, uint32_t user, uint32_t rw) {
- if (page != 0 && page->frame == 0 && page->present == 0) {
- page->present = 1;
- page->rw = (rw ? 1 : 0);
- page->user = (user ? 1 : 0);
- page->frame = frame;
- }
-}
-
-/* Modifies a page structure so that it is no longer mapped to a frame. */
-void page_unmap(struct page *page) {
- if (page != 0) {
- page->frame = 0;
- page->present = 0;
- }
-}
-
-/* Same as above but also frees the frame. */
-void page_unmapFree(struct page *page) {
- if (page != 0) {
- if (page->frame != 0) frame_free(page->frame);
- page->frame = 0;
- page->present = 0;
- }
-}
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