paging in c

6 files changed, 70 insertions, 29 deletions

diff --git a/kernel/src/boot/boot.S b/kernel/src/boot/boot.S
index ee35eeb..bf5251b 100644
--- a/kernel/src/boot/boot.S
+++ b/kernel/src/boot/boot.S
@@ -59,37 +59,25 @@ check_long_mode:
 	ret
 
 setup_page_tables:
-	mov $page_table_lvl3, %eax
+	mov $pt_lvl3, %eax
 	or $0x3, %eax
-	mov %eax, page_table_lvl4
+	mov %eax, pt_lvl4
 
-	mov $page_table_lvl2, %eax
+	// 0x00000000 -  0x00200000 : 0x00000000
+	mov $pt_lvl2, %eax
 	or $0x3, %eax
-	mov %eax, page_table_lvl3
-
-	mov $page_table_lvl2 + 4096, %eax
-	or $0x3, %eax
-	mov %eax, page_table_lvl3+8
-
-	mov $page_table_lvl2 + 8192, %eax
-	or $0x3, %eax
-	mov %eax, page_table_lvl3+16
-
-	mov $page_table_lvl2 + 12288, %eax
-	or $0x3, %eax
-	mov %eax, page_table_lvl3+24
-
+	mov %eax, pt_lvl3
 
 	movl $0, %ecx
 1:
-	movl $0x200000, %eax
+	movl $0x00200000, %eax
 	mul %ecx
 	or $0b10000011, %eax
-	movl $page_table_lvl2, %edx
+	movl $pt_lvl2, %edx
 	leal (%edx, %ecx, 8), %edx
 	movl %eax, (%edx)
 	inc %ecx
-	cmp $512*4, %ecx
+	cmp $1, %ecx
 	jne 1b
 
 	ret
@@ -106,8 +94,8 @@ enable_paging:
 	or $1<<8, %eax
 	wrmsr
 
-	// page_table_lvl4
-	mov $page_table_lvl4, %eax
+	// pt_lvl4
+	mov $pt_lvl4, %eax
 	mov %eax, %cr3
 
 	// enable paging (+ protected mode if not already enabled)
@@ -136,13 +124,13 @@ stack_bottom:
 stack_top:
 
 // page tables
-page_table_lvl4:
+pt_lvl4:
 	.skip 4096
-page_table_lvl3:
+pt_lvl3:
 	.skip 4096
 // map first 4GB
-page_table_lvl2:
-	.skip 4096*4
+pt_lvl2:
+	.skip 4096
 
 // Access bits
 .section .rodata
diff --git a/kernel/src/boot/boot64.S b/kernel/src/boot/boot64.S
index be87412..50ee7cd 100644
--- a/kernel/src/boot/boot64.S
+++ b/kernel/src/boot/boot64.S
@@ -14,6 +14,5 @@ begin_long_mode:
 
 	popq %rdi
 	popq %rsi
-
 	call kernel_main
 	hlt
diff --git a/kernel/src/devices/keyboard.c b/kernel/src/devices/keyboard.c
index bf4948d..d4b06b9 100644
--- a/kernel/src/devices/keyboard.c
+++ b/kernel/src/devices/keyboard.c
@@ -39,6 +39,12 @@ void itos(uint32_t num, char** s)
 
 void print_char(char c)
 {
+
+	if (c == '\n') {
+		x = 0;
+		y++;
+		return;
+	}
 	if (x * 8 >= fb.width) {
 		x = 0;
 		y++;
@@ -76,8 +82,7 @@ void keyboard_handler(void)
 			print_char(' ');
 			x--;
 		} else if (keycode == KEY_ENTER) {
-			x = 0;
-			y++;
+			print_char(keymap[keycode]);
 		} else {
 			if (keymap[keycode] == ' ') return;
 			if (is_pressed[KEY_LSHIFT] || is_pressed[KEY_RSHIFT])
diff --git a/kernel/src/main.c b/kernel/src/main.c
index 2653b4d..bea4ed2 100644
--- a/kernel/src/main.c
+++ b/kernel/src/main.c
@@ -3,9 +3,11 @@
 #include <graphics.h>
 #include <idt.h>
 #include <debug.h>
+#include <paging.h>
 
 int kernel_main(mb2_tag_header* multiboot_bootinfo, uint32_t multiboot_magic)
 {
+	init_paging();
 	init_idt();
 	init_fb(multiboot_bootinfo, multiboot_magic);
 
diff --git a/kernel/src/mem/paging.c b/kernel/src/mem/paging.c
new file mode 100644
index 0000000..aa7f91e
--- /dev/null
+++ b/kernel/src/mem/paging.c
@@ -0,0 +1,35 @@
+#include <stdint.h>
+#include <paging.h>
+
+void load_pt_lvl4(uint64_t*);
+
+__attribute__((aligned(4096))) uint64_t page_table_lvl4[512];
+__attribute__((aligned(4096))) uint64_t page_table_lvl3[512];
+__attribute__((aligned(4096))) uint64_t page_table_lvl2_kernel[512];
+__attribute__((aligned(4096))) uint64_t page_table_lvl2_fb[512];
+
+#define PAGE_SIZE 0x00200000
+#define FLAG_PRESENT 0x1
+#define FLAG_WRITABLE 0x2
+#define FLAG_HUGE 0x80
+
+void init_paging(void)
+{
+	page_table_lvl4[0] = (uint64_t)page_table_lvl3 + FLAG_PRESENT + FLAG_WRITABLE;
+	page_table_lvl3[0] = (uint64_t)page_table_lvl2_kernel + FLAG_PRESENT + FLAG_WRITABLE;
+	page_table_lvl3[3] = (uint64_t)page_table_lvl2_fb + FLAG_PRESENT + FLAG_WRITABLE;
+
+	// 0x00000000 - 0x00400000 : 0x00000000 - 0x00400000
+	for (uint64_t i = 0; i < 2; i++) {
+		page_table_lvl2_kernel[i] = i * PAGE_SIZE + FLAG_PRESENT + FLAG_WRITABLE + FLAG_HUGE;
+	}
+
+	// TODO: remove initial mapping for fb and instead page on demand
+
+	// 0xe0000000 - 0xffffffff : 0xe0000000 - 0xffffffff
+	for (uint64_t i = 0; i < 512; i++) {
+		page_table_lvl2_fb[i] = i * PAGE_SIZE + 0xc0000000 + FLAG_PRESENT + FLAG_WRITABLE + FLAG_HUGE;
+	}
+
+	load_pt_lvl4(page_table_lvl4);
+}
diff --git a/kernel/src/mem/paging_asm.S b/kernel/src/mem/paging_asm.S
new file mode 100644
index 0000000..5a1dcf7
--- /dev/null
+++ b/kernel/src/mem/paging_asm.S
@@ -0,0 +1,12 @@
+.section .text
+
+.global load_pt_lvl4
+load_pt_lvl4:
+    push %rbp
+    mov %rsp, %rbp
+
+    mov %rdi, %cr3
+
+    mov %rbp, %rsp
+    pop %rbp
+    ret