gdt & tss

12 files changed, 122 insertions, 27 deletions

diff --git a/kernel/src/boot/boot.S b/kernel/src/boot/boot.S
index 81584ce..e0c5326 100644
--- a/kernel/src/boot/boot.S
+++ b/kernel/src/boot/boot.S
@@ -1,10 +1,10 @@
 .code32
-.global _start
 .extern begin_long_mode
 
 .set KERNEL_VMA, 0xc0000000
 
 .section .boot.text, "a"
+.global _start
 _start:
 	cli
 	mov $stack_top - KERNEL_VMA, %esp
@@ -136,7 +136,7 @@ no_long_mode:
 
 .section .text
 4:
-	lgdt gdt_pointer
+	lgdt gdtp
 	ljmp $0x08, $begin_long_mode
 
 
@@ -189,9 +189,6 @@ gdt_data = . - gdt
 	.byte PRESENT | NOT_SYS | RW
 	.byte GRAN_4K | SZ_32 | 0xF
 	.byte 0
-gdt_tss = . - gdt
-	.long 0x00000068
-	.long 0x00CF8900
-gdt_pointer:
+gdtp:
 	.word . - gdt - 1
 	.quad gdt
diff --git a/kernel/src/boot/boot64.S b/kernel/src/boot/boot64.S
index 50ee7cd..68eae38 100644
--- a/kernel/src/boot/boot64.S
+++ b/kernel/src/boot/boot64.S
@@ -1,8 +1,7 @@
-.global begin_long_mode
-
 .section .text
 .code64
 
+.global begin_long_mode
 begin_long_mode:
 	// reload segment registers
 	mov $0x10, %eax
diff --git a/kernel/src/cpu/gdt.c b/kernel/src/cpu/gdt.c
new file mode 100644
index 0000000..b4f1ec0
--- /dev/null
+++ b/kernel/src/cpu/gdt.c
@@ -0,0 +1,53 @@
+#include <gdt.h>
+#include <tss.h>
+
+gdt_seg_entry gdt[7];
+gdt_p gdt_pointer;
+
+void add_gdt_entry(uint32_t num, uint32_t offset, uint32_t limit, uint8_t access, uint8_t flags)
+{
+	gdt[num].offset1 = offset & 0xffff;
+	gdt[num].offset2 = (offset >> 16) & 0xff;
+	gdt[num].offset3 = (uint8_t)(offset >> 24) & 0xff;
+	gdt[num].limit = limit & 0xffff;
+	gdt[num].limitflags = (limit >> 16) & 0xf;
+	gdt[num].access = access;
+	gdt[num].limitflags = flags << 4;
+}
+
+void add_gdt_tss(uint32_t num, uint64_t offset, uint32_t limit, uint8_t access, uint8_t flags)
+{
+	add_gdt_entry(num, offset & 0xffffffff, limit, access, flags);
+}
+
+void reload_gdt()
+{
+	__asm__ volatile (
+			"mov $0x10, %ax;"
+			"mov %ax, %ds;"
+			"mov %ax, %es;"
+			"mov %ax, %ss;"
+			);
+}
+
+void load_gdt(gdt_p* pointer)
+{
+	__asm__ volatile ("lgdt (%0);" : : "r"(pointer) : );
+	reload_gdt();
+}
+
+void init_gdt()
+{
+	gdt_pointer.offset = (uint64_t)&gdt;
+	gdt_pointer.size = sizeof(gdt) - 1;
+
+	add_gdt_entry(0, 0, 0, 0, 0);
+	add_gdt_entry(1, 0, 0xfffff, 0x9a, 0xa);
+	add_gdt_entry(2, 0, 0xfffff, 0x92, 0xc);
+	add_gdt_entry(3, 0, 0xfffff, 0xfa, 0xa);
+	add_gdt_entry(4, 0, 0xfffff, 0xf2, 0xc);
+	add_gdt_tss(5, (uint64_t)&tss, sizeof(tss_type), 0x89, 0);
+
+	load_gdt(&gdt_pointer);
+	init_tss();
+}
diff --git a/kernel/src/cpu/irq.c b/kernel/src/cpu/irq.c
index 096860a..a19a7f1 100644
--- a/kernel/src/cpu/irq.c
+++ b/kernel/src/cpu/irq.c
@@ -8,7 +8,7 @@
 #include <paging.h>
 #include <libk/stdio.h>
 
-const char* exception_name[] = {
+const char* const exception_name[] = {
 	"Divide-by-zero Error",
 	"Debug",
 	"Non-maskable Interrupt",
@@ -120,8 +120,9 @@ void isr13_handler(uint64_t error)
 
 void isr14_handler(uint64_t error)
 {
-	page_fault(error);
 	printf("%s\n", exception_name[14]);
+	printf("error: %d\n", error);
+	page_fault(error);
 }
 
 void isr15_handler(void)
diff --git a/kernel/src/cpu/irq_stub.S b/kernel/src/cpu/irq_stub.S
index 4db722e..9b2b2d8 100644
--- a/kernel/src/cpu/irq_stub.S
+++ b/kernel/src/cpu/irq_stub.S
@@ -38,11 +38,9 @@ isr\number:
 .macro isr_error number
 .global isr\number
 isr\number:
-	add $8, %rsp
+	pop %rdi
 	pushall
 	cld
-	# setting error to 0
-	mov $0, %rdi
 	call isr\number\()_handler
 	popall
 	iretq
diff --git a/kernel/src/cpu/tss.c b/kernel/src/cpu/tss.c
new file mode 100644
index 0000000..c7f9dc2
--- /dev/null
+++ b/kernel/src/cpu/tss.c
@@ -0,0 +1,15 @@
+#include <tss.h>
+
+tss_type tss;
+
+void load_tss()
+{
+	__asm__ volatile ("mov $0x28, %ax; ltr %ax;");
+}
+
+void init_tss()
+{
+	tss.iopb = sizeof(tss_type);
+
+	load_tss();
+}
diff --git a/kernel/src/fs/ext2.c b/kernel/src/fs/ext2.c
index 11f26fc..5395dd0 100644
--- a/kernel/src/fs/ext2.c
+++ b/kernel/src/fs/ext2.c
@@ -24,6 +24,12 @@ void read_superblock(ext2_superblock_t* superblock)
 	memcpy(superblock, block, sizeof(ext2_superblock_t));
 }
 
+void ext2_init()
+{
+	ext2_superblock = (ext2_superblock_t*)kalloc(sizeof(ext2_superblock_t));
+	read_superblock(ext2_superblock);
+}
+
 void read_bg_desc(uint32_t bg_desc, ext2_bg_desc_t* ext2_bg_desc)
 {
 	uint32_t starting_block_num = BLOCK_SIZE == 1024 ? 2 : 1;
diff --git a/kernel/src/main.c b/kernel/src/main.c
index c575a0e..45d2eeb 100644
--- a/kernel/src/main.c
+++ b/kernel/src/main.c
@@ -11,27 +11,23 @@
 #include <disc.h>
 #include <ext2.h>
 #include <timer.h>
+#include <gdt.h>
+#include <userspace.h>
+#include <tss.h>
 
 int kernel_main(mb2_tag_header* multiboot_bootinfo, uint32_t multiboot_magic);
 int kernel_main(mb2_tag_header* multiboot_bootinfo, uint32_t multiboot_magic)
 {
+	init_gdt();
 	init_paging();
 	init_idt();
 	init_timer(TICKS_PER_SECOND);
 	init_heap();
 	read_mb2(multiboot_bootinfo, multiboot_magic);
-
-	// init disc
 	disc_init();
-
-	// read superblock
-	ext2_superblock = (ext2_superblock_t*)kalloc(sizeof(ext2_superblock_t));
-	read_superblock(ext2_superblock);
-
-	ls(path_to_inode("/"));
-
-	// free superblock
-	kfree(ext2_superblock);
+	ext2_init();
+//	ls(path_to_inode("/"));
+//	jump_userspace();
 
 	for(;;) {
 		__asm__ volatile ("hlt;");
diff --git a/kernel/src/mem/paging.c b/kernel/src/mem/paging.c
index 531c300..630fb6d 100644
--- a/kernel/src/mem/paging.c
+++ b/kernel/src/mem/paging.c
@@ -51,9 +51,10 @@ void init_paging(void)
 	page_table_lvl3[2] = (uint64_t)page_table_lvl2_2 + FLAG_PRESENT + FLAG_WRITABLE - KERNEL_VMA;
 	page_table_lvl3[3] = (uint64_t)page_table_lvl2_3 + FLAG_PRESENT + FLAG_WRITABLE - KERNEL_VMA;
 
-	// higher half map first 4mb
-	map_addr(KERNEL_VMA, 0x00000000, FLAG_PRESENT + FLAG_WRITABLE + FLAG_HUGE);
-	map_addr(KERNEL_VMA + PAGE_SIZE, 0x00000000 + PAGE_SIZE, FLAG_PRESENT + FLAG_WRITABLE + FLAG_HUGE);
+	// higher half map first 6mb
+	for (size_t i = 0; i < 3; i++) {
+		map_addr(KERNEL_VMA + PAGE_SIZE * i, 0x00000000 + PAGE_SIZE * i, FLAG_PRESENT + FLAG_WRITABLE + FLAG_HUGE);
+	}
 
 	load_pt_lvl4(page_table_lvl4);
 }
diff --git a/kernel/src/sys/syscall.S b/kernel/src/sys/syscall.S
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/kernel/src/sys/syscall.S
diff --git a/kernel/src/sys/userspace.c b/kernel/src/sys/userspace.c
new file mode 100644
index 0000000..4add4d5
--- /dev/null
+++ b/kernel/src/sys/userspace.c
@@ -0,0 +1,9 @@
+#include <types.h>
+#include <userspace.h>
+
+void begin_userspace()
+{
+	while(true) {
+
+	}
+}
diff --git a/kernel/src/sys/userspace_asm.S b/kernel/src/sys/userspace_asm.S
new file mode 100644
index 0000000..5838051
--- /dev/null
+++ b/kernel/src/sys/userspace_asm.S
@@ -0,0 +1,20 @@
+.text
+
+.extern begin_userspace
+
+.global jump_userspace
+jump_userspace:
+	mov $0x23, %ax
+	mov %ax, %ds
+	mov %ax, %es
+	mov %ax, %fs
+	mov %ax, %gs
+
+	mov %esp, %eax
+	push $0x23
+	push %rax
+	pushf
+	push $0x1b
+	sub $8, %rsp
+	movabs $begin_userspace, %rsp
+	iretq