Added basic paging.h & paging.c

kernel/include/bootloader.h

@@ -16,12 +16,13 @@
 #define BOOT_MMAP_NVS		4
 #define BOOT_MMAP_BADRAM	5
 
+#define BOOT_MAX_MMAP_ENTRIES	128
+
 // A memory map entry
 struct boot_memmap {
-	uint32_t skip;	// Used for skipping (may be padded for alignment)
 	uint64_t base;	// Memory region address
 	uint64_t size;	// Memory region length
-	uint32_t type;	// Memory region type
+	uint8_t  type;	// Memory region type
 } __packed;
 
 /*
@@ -39,7 +40,7 @@ struct boot_info {
 	uint8_t bootPart2;
 	uint8_t bootPart3;
 	char* cmdline;
-	uint32_t memmap;
+	struct boot_memmap* memmap;
 	size_t memmapLen;
 	char* bootname;
 } __packed;

kernel/include/paging.h

@@ -0,0 +1,25 @@
+#ifndef _PAGING_H
+#define _PAGING_H
+
+#include <kernel.h>
+
+#define PAGE_SIZE	4096
+
+#define PHYS_ADDR(_a)	((_a) & ~0xfff)
+
+#define PAGE_FLAG_PRESENT	(1 << 0)
+#define PAGE_FLAG_WRITE		(1 << 1)
+#define PAGE_FLAG_USER		(1 << 2)
+#define PAGE_FLAG_PWT		(1 << 3)
+#define PAGE_FLAG_NOCACHE	(1 << 4)
+#define PAGE_FLAG_ACCESSED	(1 << 5)
+#define PAGE_FLAG_DIRTY		(1 << 6)
+#define PAGE_FLAG_4MB		(1 << 7)
+#define PAGE_FLAG_GLOBAL	(1 << 8)
+
+// Defined in entry.s for initial paging
+extern uint32_t init_pagedir[1024];
+
+int pag_init(void);
+
+#endif

kernel/src/bootloader.c

@@ -1,7 +1,9 @@
 #include <bootloader.h>
 #include <multiboot.h>
 #include <kernel.h>
+#include <string.h>
 
+struct boot_memmap memmap[BOOT_MAX_MMAP_ENTRIES];
 struct boot_info bootloader;
 
 // TODO:
@@ -39,8 +41,21 @@ int boot_initMB1(void* ptr, uint32_t magic) {
 	
 	// mmap_* fields are valid
 	if (mbi->flags & MULTIBOOT_INFO_MEM_MAP) {
-		bootloader.memmap = mbi->mmap_addr;
+		bootloader.memmap = &memmap[0];
-		bootloader.memmapLen = mbi->mmap_length;
+
+		size_t i = 0;
+		multiboot_memory_map_t* entry = (multiboot_memory_map_t*)mbi->mmap_addr;
+		uint32_t mapLim = mbi->mmap_addr + mbi->mmap_length;
+
+		while ((uint32_t)entry < mapLim) {
+			bootloader.memmap[i].base = entry->addr;
+			bootloader.memmap[i].size = entry->len;
+			bootloader.memmap[i].type = (uint8_t)entry->type;
+
+			entry++;
+			i++;
+		}
+		bootloader.memmapLen = i;
 	}
 
 	// TODO: drives_*

kernel/src/kernel.c

@@ -1,8 +1,10 @@
 #include <bootloader.h>
 #include <kernel.h>
+#include <paging.h>
 #include <serial.h>
 #include <gdt.h>
 #include <isr.h>
+#include <pmm.h>
 #include <tty.h>
 
 // TODO: Commented out stuff
@@ -27,27 +29,9 @@ void kmain(void* ptr, uint32_t magic) {
 
 	gdt_init();
 	isr_init();
-	// pag_init();
+	pag_init();
 
 	debugf("Basic initialization complete!\n");
-
-	struct boot_memmap* entry;
-	for (
-		entry = (struct boot_memmap*)bootloader.memmap;
-		(uint64_t)entry < bootloader.memmap + bootloader.memmapLen;
-		entry = (struct boot_memmap*)((uint64_t)entry + entry->skip + sizeof(entry))
-	) {
-
-		debugf("[Region] base: %x size: %x b type: ", entry->base, entry->size);
-		switch (entry->type) {
-		case BOOT_MMAP_AVAILABLE:	debugf("Available\n"); break;
-		case BOOT_MMAP_RESERVED:	debugf("Reserved\n"); break;
-		case BOOT_MMAP_ACPI_RECLAIM:	debugf("ACPI Reclaim\n"); break;
-		case BOOT_MMAP_NVS:		debugf("NVS\n"); break;
-		case BOOT_MMAP_BADRAM:		debugf("Bad RAM\n"); break;
-		default:			debugf("Invalid type\n"); break;
-		}
-	}
 	
 	panic("kmain() reached end.");
 

kernel/src/paging.c

@@ -0,0 +1,27 @@
+#include <kernel.h>
+#include <string.h>
+#include <paging.h>
+
+// Invalidates the pagedir entry in the CPUs TLB cache
+static inline void invalidate(uint32_t vaddr) {
+	__asm__ volatile ("invlpg %0" : : "m"(vaddr));
+}
+
+int pag_init(void) {
+	// Unmap first MB
+	init_pagedir[0] = 0;
+	invalidate(0);
+
+	/*
+	 * Recursive table mapping
+	 * We map the last pagetab to the pagedir itself, so it acts
+	 * as a pagetab even though it's a pagedir. This maps it to
+	 * the virtual address 0xFFFFF000.
+	 */
+	init_pagedir[1023] = ((uint32_t)init_pagedir - 0xC0000000) |
+		PAGE_FLAG_PRESENT | PAGE_FLAG_WRITE;
+	invalidate(0xFFFFF000);
+
+	return 0;
+}
+

kernel/src/pmm.c

@@ -1,22 +1,27 @@
-#include <multiboot.h>
+#include <bootloader.h>
 #include <kernel.h>
+#include <string.h>
 #include <pmm.h>
 
-// Helpers
+// Bitmap & helpers
-#define SET_BLOCK(_b)	memmap[(_b) / 32] |= (1 << ((_b) % 32))
+uint32_t* bitmap = NULL;
-#define USET_BLOCK(_b)	memmap[(_b) / 32] &= ~(1 << ((_b) % 32))
+#define SET_BLOCK(_b)	bitmap[(_b) / 32] |= (1 << ((_b) % 32))
-#define TEST_BLOCK(_b)	((memmap[(_b) % 32] & (1 << ((_b) % 32))) ? 1 : 0)
+#define USET_BLOCK(_b)	bitmap[(_b) / 32] &= ~(1 << ((_b) % 32))
+#define TEST_BLOCK(_b)	((bitmap[(_b) % 32] & (1 << ((_b) % 32))) ? 1 : 0)
 
-// Memory manager bitmap
+// Status
-uint32_t* memmap = NULL;
 size_t usedBlocks = 0;
 size_t maxBlocks = 0;
 
-// TODO: improve these hardcoded values
 int pmm_init(void) {
-	memmap = NULL;	// Memory map location
+	size_t totalmem = (bootloader.memLower + bootloader.memUpper) * 1024;
-	usedBlocks = 0;
+	maxBlocks = totalmem / PMM_BS;
-	maxBlocks = 0; // TODO
+	usedBlocks = maxBlocks;
+
+	// TODO:
+	bitmap = (uint32_t*)NULL;
+	memset(bitmap, 0, maxBlocks / PMM_BPB);
+
 	return 0;
 }
 
@@ -27,7 +32,7 @@ int findFreeBlocks(size_t blockCount) {
 	uint32_t freeCount = 0;
 	for (size_t i = 0; i < max; i++) {
 		// We don't have to check, cause it's all reserved
-		if (memmap[i] == 0xffffffff) continue;
+		if (bitmap[i] == 0xffffffff) continue;
 
 		for (uint8_t j = 0; j < 32; j++) {
 			if (TEST_BLOCK(i * PMM_BPB + j)) freeCount++;