organization

src/kernel/gdt.c

@@ -1,36 +1,16 @@
-//#include "../include/gdt.h"
-#include <stdint.h>
+#include "../include/gdt.h"
 #include "../include/string.h"
+#include "../include/paging.h"
 
-struct desc_r {
-	uint16_t limit;
-	uint32_t base_addr;
-} __attribute__((packed));
-
-struct seg_desc {
-	unsigned sd_lolimit : 16;	/* segment limit 0-15 bits */
-	unsigned sd_lobase  : 24;	/* base address 0-23 bits */
-	unsigned sd_loflags :  8;	/* flags (P, DPL, S and TYPE) */
-	unsigned sd_hilimit :  4;	/* segment limit 16-19 bits */
-	unsigned sd_hiflags :  4;	/* flags (G, DB, 0 and AVL) */
-	unsigned sd_hibase  :  8;	/* base address 24-31 bits */
-} __attribute__((packed));
-
-struct gate_desc {
-	unsigned gd_looffset: 16;	/* offset 0-15 bits */
-	unsigned gd_selector: 16;	/* segment selector */
-	unsigned gd_flags   : 16;	/* flags (P, DPL, TYPE, 0 and NULL) */
-	unsigned gd_hioffset: 16;	/* offset 16-31 bits */
-} __attribute__((packed));
-
-extern char _end[], _edata[];
-
-#define KERNEL_CS       0x08    /* kernel code segment */
-#define KERNEL_DS       0x10    /* kernel data segment */
-#define USER_CS         0x18    /* user code segment */
-#define USER_DS         0x20    /* user data segment */
-#define TSS             0x28    /* TSS segment */
+void bss_init()
+{
+	memset((void *)((int)_edata), 0, KERNEL_BSS_SIZE);
+}
 
+uint32_t get_last_boot_addr()
+{
+	return ((uint32_t)_end & PAGE_MASK) + PAGE_SIZE;
+}
 
 void load_gdt(uint32_t gdt_ptr) {
     asm volatile (
@@ -49,95 +29,7 @@ void load_gdt(uint32_t gdt_ptr) {
     );
 }
 
-#define PAGE_SIZE		4096
-#define PAGE_SHIFT		0x0C
-
-#define PAGE_MASK		~(PAGE_SIZE - 1)	/* 0xFFFFF000 */
-#define PAGE_ALIGN(addr)	(((addr) + (PAGE_SIZE - 1)) & PAGE_MASK)
-
-#define KERNEL_BSS_SIZE		((int)_end - (int)_edata)
-
-#define NR_GDT_ENTRIES	6	/* entries in GDT descriptor */
-#define NR_IDT_ENTRIES	256	/* entries in IDT descriptor */
-
-/* low flags of Segment Descriptors */
-#define SD_CODE		0x0A	/* CODE Exec/Read */
-#define SD_DATA		0x02	/* DATA Read/Write */
-
-#define SD_32INTRGATE	0x0E	/* 32-bit Interrupt Gate (0D110) */
-#define SD_32TRAPGATE	0x0F	/* 32-bit Trap Gate (0D111) */
-
-#define SD_CD 		0x10	/* 0 = system / 1 = code/data */
-#define SD_DPL0		0x00	/* priority level 0 (kernel) */
-#define SD_DPL3		0x60	/* priority level 3 (user) */
-#define SD_PRESENT	0x80	/* segment present or valid */
-
-/* high flags Segment Descriptors */
-#define SD_OPSIZE32	0x04	/* 32-bit code and data segments */
-#define SD_PAGE4KB	0x08	/* page granularity (4KB) */
-
-/* low flags of the TSS Descriptors */
-#define SD_TSSPRESENT	0x89	/* TSS present and not busy flag */
-
-/* EFLAGS */
-#define EF_IOPL		12	/* IOPL bit */
-
-#define KERNEL_CS	0x08	/* kernel code segment */
-#define KERNEL_DS	0x10	/* kernel data segment */
-#define USER_CS		0x18	/* user code segment */
-#define USER_DS		0x20	/* user data segment */
-#define TSS		0x28	/* TSS segment */
-
-
-struct tss_entry_struct {
-	uint32_t prev_tss; // The previous TSS - with hardware task switching these form a kind of backward linked list.
-	uint32_t esp0;     // The stack pointer to load when changing to kernel mode.
-	uint32_t ss0;      // The stack segment to load when changing to kernel mode.
-	// Everything below here is unused.
-	uint32_t esp1; // esp and ss 1 and 2 would be used when switching to rings 1 or 2.
-	uint32_t ss1;
-	uint32_t esp2;
-	uint32_t ss2;
-	uint32_t cr3;
-	uint32_t eip;
-	uint32_t eflags;
-	uint32_t eax;
-	uint32_t ecx;
-	uint32_t edx;
-	uint32_t ebx;
-	uint32_t esp;
-	uint32_t ebp;
-	uint32_t esi;
-	uint32_t edi;
-	uint32_t es;
-	uint32_t cs;
-	uint32_t ss;
-	uint32_t ds;
-	uint32_t fs;
-	uint32_t gs;
-	uint32_t ldt;
-	uint16_t trap;
-	uint16_t iomap_base;
-} __packed;
-
-void bss_init()
-{
-	memset((void *)((int)_edata), 0, KERNEL_BSS_SIZE);
-}
-
-uint32_t get_last_boot_addr()
-{
-	return ((unsigned int)_end & PAGE_MASK) + PAGE_SIZE;
-}
-
-struct seg_desc gdt[NR_GDT_ENTRIES];
-
-struct desc_r gdtr = {
-	sizeof(gdt) - 1,
-	(unsigned int)&gdt
-};
-
-static void gdt_set_entry(int num, unsigned int base_addr, unsigned int limit, char loflags, char hiflags)
+static void gdt_set_entry(int num, uint32_t base_addr, uint32_t limit, char loflags, char hiflags)
 {
 	num /= sizeof(struct seg_desc);
 	gdt[num].sd_lolimit = limit & 0xFFFF;
@@ -150,7 +42,7 @@ static void gdt_set_entry(int num, unsigned int base_addr, unsigned int limit, c
 
 void gdt_init(void)
 {
-	unsigned char loflags;
+	uint8_t loflags;
 
 	gdt_set_entry(0, 0, 0, 0, 0);	/* null descriptor */
 
@@ -167,5 +59,5 @@ void gdt_init(void)
 	loflags = SD_TSSPRESENT;
 	gdt_set_entry(TSS, 0, sizeof(struct tss_entry_struct), loflags, SD_OPSIZE32);
 
-	load_gdt((unsigned int)&gdtr);
+	load_gdt((uint32_t)&gdtr);
 }

src/kernel/kernel.c

@@ -155,9 +155,9 @@ void kmain(unsigned int magic, unsigned int info)
 
 	apply_pic_masks();
 
-	paging_init();
-	printf("paging_init done\n");
-	test_paging();
+	//paging_init();
+	//printf("paging_init done\n");
+	//test_paging();
 	init_allocator();
 	heap_init();
 	printf("after heap_init\n");