Rewrite finished

Makefile

@@ -1,54 +1,67 @@
-ASM ?= nasm
+ASM := nasm
+
 CC := x86_64-elf-gcc
-GDB := gdb
+CCFLAGS := 
+
 LD := x86_64-elf-ld
+LDFLAGS := 
 
-C_FILES = $(shell find src/ -type f -name '*.c')
-CO_FILES = $(patsubst src/%.c, obj/%.o, $(C_FILES))
-ASM_FILES = $(shell find src/kernel/ -type f -name '*.asm')
-AO_FILES = $(patsubst src/kernel/%.asm, obj/kernel/%.o, $(ASM_FILES))
+INCLUDE := include/
 
-KERNEL_O_FILES = ${CO_FILES} ${AO_FILES}
+# Target: kernel, type: C ASM
+kernel_c_source_files = $(shell find src/kernel/ -type f -name *.c)
+kernel_c_object_files = $(patsubst src/%.c,obj/%.o,$(kernel_c_source_files))
+kernel_asm_source_files = $(shell find src/kernel/ -type f -name *.asm)
+kernel_asm_object_files = $(patsubst src/%.asm,obj/%.o,$(kernel_asm_source_files))
+kernel_source_files = $(kernel_c_source_files) $(kernel_asm_object_files)
+kernel_object_files = $(kernel_c_object_files) $(kernel_asm_object_files)
 
-BOOT_O_FILES = obj/entry.o obj/entry64.o obj/mb2.o obj/vga-print.o
-BOOT_SRC_FILES = obj/entry.asm obj/entry64.asm obj/mb2.asm obj/vga-print.asm
+# Target: libc, type: C ASM
+libc_c_source_files = $(shell find src/libc/ -type f -name *.c)
+libc_c_object_files = $(patsubst src/%.c,obj/%.o,$(libc_c_source_files))
+libc_asm_source_files = $(shell find src/libc/ -type f -name *.asm)
+libc_asm_object_files = $(patsubst src/%.asm,obj/%.o,$(libc_c_object_files))
+libc_source_files = $(libc_c_source_files) $(libc_asm_source_files)
+libc_object_files = $(libc_c_object_files) $(libc_asm_object_files)
 
-iso: bin/shade.iso
+# Target: sboot, type: ASM
+# Override: 32-bit
+sboot_asm_source_files = $(shell find src/boot/ -type f -name *.asm)
+sboot_asm_object_files = $(patsubst src/%.asm,obj/%.o,$(sboot_asm_source_files))
+sboot_source_files = $(sboot_asm_source_files)
+sboot_object_files = $(sboot_asm_object_files)
 
-bin/shade.bin: ${BOOT_O_FILES} ${KERNEL_O_FILES}
-	mkdir -p bin
-	$(LD) -T src/linker.ld $^ -o $@
-	grub-file --is-x86-multiboot2 bin/shade.bin
+shade_bin_ldfile = src/linker.ld
+
+default: run
 
 bin/shade.iso: bin/shade.bin
-	mkdir -p isodir/boot/grub
-	cp bin/shade.bin isodir/boot/shade.bin
-	cp src/iso/grub.cfg isodir/boot/grub/grub.cfg
-	grub-mkrescue -o bin/shade.iso isodir
-	rm -rf isodir
+	cp bin/shade.bin src/iso/boot/shade.bin
+	grub-mkrescue src/iso/ -o $@
+	rm src/iso/boot/shade.bin
 
+bin/shade.bin: $(sboot_object_files) $(kernel_object_files) $(libc_object_files)
+	mkdir -p "$(@D)"
+	$(LD) $(LDFLAGS) -n -T $(shade_bin_ldfile) $^ -o $@
+	grub-file --is-x86-multiboot2 $@
+
+# Generics
+# Source file types: C ASM
+
+# C
 obj/%.o: src/%.c
 	mkdir -p "$(@D)"
-	$(CC) -ffreestanding -O2 -Wall -Wextra -c $< -o $@
+	$(CC) $(CCFLAGS) -I $(INCLUDE) -ffreestanding -c $< -o $@
 
+# ASM
 obj/%.o: src/%.asm
 	mkdir -p "$(@D)"
-	$(ASM) -f elf64 $< -o $@
-
+	$(ASM) -felf64 $< -o $@
 
+# Other
 run: clean bin/shade.iso
-	qemu-system-x86_64 -hdd bin/shade.iso -d int -no-reboot
-
-debug: clean bin/shade.iso bin/shade.bin
-	qemu-system-x86_64 -s -S -hdd bin/shade.iso -d int -no-reboot &
-	${GDB} os-image.bin -ex "set arch i386:x86-64" -ex "symbol-file bin/shade.bin" -ex "target remote localhost:1234"
-
+	qemu-system-x86_64 -drive file=bin/shade.iso,index=0,media=disk,format=raw
 
 clean:
-	find obj -type f -name '*.o' -exec rm {} +
-	find obj -type f -name '*.bin' -exec rm {} +
-	find bin -type f -name '*.o' -exec rm {} +
-	find bin -type f -name '*.bin' -exec rm {} +
-	find . -type f -name '*.dis' -exec rm {} +
-	rm -f kernel.elf
-	rm -rf isodir
+	rm -rf bin/*
+	rm -rf obj/*

include/shade/platform/ports.h

@@ -0,0 +1,4 @@
+unsigned char port_byte_in(unsigned short port);
+void port_byte_out(unsigned short port, unsigned char data);
+unsigned short port_word_in(unsigned short port);
+void port_word_out(unsigned short port, unsigned short data);

src/boot/entry.asm

@@ -0,0 +1,141 @@
+
+  
+global entry_x86
+extern entry_x64
+
+section .text
+bits 32
+entry_x86:
+    mov esp, stack_top
+    
+    call check_mb2_boot
+    call check_cpuid
+    call check_x64_supported
+    
+    call setup_page_tables
+    call enable_paging
+    
+    lgdt [gdt64.pointer]
+    jmp gdt64.code_segment:entry_x64 ; Jump into 64 bit entry
+    
+    hlt
+
+check_mb2_boot:
+    cmp eax, 0x36d76289 ; compare eax to mb2 magic number
+    jne .mb2_not_booted
+    ret
+.mb2_not_booted:
+    mov al, "B" ; err code B - boot error
+    jmp error
+
+check_cpuid:
+    pushfd ; Put flags on stack so we can mess with them
+    pop eax ; then put the stack into EAX so we can easily modify it
+    mov ecx, eax ; Make a copy of eax in ecx for comparison
+    xor eax, 1 << 21 ; Attempt to flip the CPUID bit which is bit 21
+    push eax ; Put eax back onto stack
+    popfd ; Write flags back
+    pushfd ; Copy flags onto stack so we can check if the bit did flip
+    pop eax ; Put stack into EAX for comparison
+    push ecx ; Put original flags into stack so we can make sure they remain unchanged
+    popfd; Push original flags back onto the flags register
+    cmp eax, ecx ; Compare the modifided? flags to the original flags
+    je .cpuid_unsupported ; Flags were not changed, cpuid not supported
+    ret
+    
+.cpuid_unsupported:
+    mov al, "C" ; err code C - cpuid unsupported
+    jmp error
+    
+check_x64_supported:
+    mov eax, 0x80000000 ; Magic code that i dont understand
+	cpuid ; Magic code that i dont understand
+	cmp eax, 0x80000001 ; Magic code that i dont undetstand
+	jb .x64_unsupported ; Something went wrong so x64 isnt supported
+
+	mov eax, 0x80000001 ; Set magic value 0x80000001 into EAX for cpuid
+	cpuid ; Get "extended features list" from CPU info
+	test edx, 1 << 29 ; Check if x64 is supported by checking bit 29
+	jz .x64_unsupported ; If zero, x64 unsupported so jump to no x64
+    
+    ret
+.x64_unsupported:
+    mov al, "L" ; err code L, long mode/x64 unsupported
+    jmp error
+
+; Magic paging code that I don't understand
+setup_page_tables:
+	mov eax, page_table_l3
+	or eax, 0b11 ; present, writable
+	mov [page_table_l4], eax
+	
+	mov eax, page_table_l2
+	or eax, 0b11 ; present, writable
+	mov [page_table_l3], eax
+
+	mov ecx, 0 ; counter
+.loop:
+
+	mov eax, 0x200000 ; 2MiB
+	mul ecx
+	or eax, 0b10000011 ; present, writable, huge page
+	mov [page_table_l2 + ecx * 8], eax
+
+	inc ecx ; increment counter
+	cmp ecx, 512 ; checks if the whole table is mapped
+	jne .loop ; if not, continue
+
+	ret
+
+enable_paging:
+	; pass page table location to cpu
+	mov eax, page_table_l4
+	mov cr3, eax
+
+	; enable PAE
+	mov eax, cr4
+	or eax, 1 << 5
+	mov cr4, eax
+
+	; enable long mode
+	mov ecx, 0xC0000080
+	rdmsr
+	or eax, 1 << 8
+	wrmsr
+
+	; enable paging
+	mov eax, cr0
+	or eax, 1 << 31
+	mov cr0, eax
+
+	ret
+
+error:
+	; print "ERR: X" where X is the error code
+	mov dword [0xb8000], 0x4f524f45
+	mov dword [0xb8004], 0x4f3a4f52
+	mov dword [0xb8008], 0x4f204f20
+	mov byte  [0xb800a], al
+	hlt
+
+section .bss
+align 4096
+page_table_l4:
+	resb 4096
+page_table_l3:
+	resb 4096
+page_table_l2:
+	resb 4096
+stack_bottom:
+	resb 4096 * 4
+stack_top:
+
+section .rodata
+gdt64:
+	dd 0 ; zero entry
+	dd 0
+.code_segment: equ $ - gdt64
+	dq (1 << 43) | (1 << 44) | (1 << 47) | (1 << 53) ; code segment
+.pointer:
+	dw $ - gdt64 - 1 ; length
+	dq gdt64 ; address

src/boot/entry64.asm

@@ -0,0 +1,17 @@
+global entry_x64
+extern kmain
+
+section .text
+bits 64
+entry_x64:
+    ; Nullify all data registers
+    mov ax, 0
+    mov ss, ax
+    mov ds, ax
+    mov es, ax
+    mov fs, ax
+    mov gs, ax
+    
+    call kmain ; Jump into C kernel entry
+    
+    hlt

src/boot/mb2_header.asm

@@ -0,0 +1,16 @@
+section .mb2_header
+header_start:
+    ; https://www.gnu.org/software/grub/manual/multiboot2/multiboot.html for more information, section 3.1.1
+    dd 0xe85250d6 ; multiboot2 magic number
+    
+    dd 0 ; i386 protected 32 bit mode
+    
+    dd header_end - header_start ; Header length
+    
+    dd 0x100000000 - (0xe85250d6 + 0 + (header_end - header_start)) ; Checksum, total is 0
+    
+    ; Ending tag
+	  dw 0
+	  dw 0
+	  dd 8
+header_end:

src/iso/boot/grub/grub.cfg

@@ -0,0 +1,7 @@
+set timeout=5
+set default=0
+
+menuentry "shadeOS Development Build" {
+    multiboot2 /boot/shade.bin
+    boot
+}

src/iso/grub.cfg

@@ -1,6 +0,0 @@
-set timeout=0
-set default=0
-
-menuentry "shadeOS Dev Build" {
-    multiboot /boot/shade.bin
-}

src/kernel/kernel.c

@@ -1,7 +1,5 @@
-#include "./platform/ports.h"
-#include "print.h"
-
-void dummy_test_entrypoint() {}
+#include <shade/platform/ports.h>
+#include <shade/print.h>
 
 void kernel_welcome() {
     print_str("Welcome to ");
@@ -44,4 +42,5 @@ void kmain() {
     print_str("Copyright (c) e3team 2022. All rights reserved.\n");
     print_str("This program is provided \"as-is\" and no express or implied warranty is provided.\n");
     print_str("The full license can be found at /sys/LICENCE on this system or ./LICENCE in the source tree.\n");
+
 }

src/kernel/platform/ports.c

@@ -0,0 +1,26 @@
+/*
+ * Read 1 byte from specified port
+ */
+unsigned char port_byte_in(unsigned short port) {
+    unsigned char result;
+    // source and dest are backwards.
+    // "=a (result)" set the C variable to the value of register e'a'x
+    // '"d" (port) map the C variable port into e'd'x register
+    __asm__("in %%dx, %%al" : "=a" (result) : "d" (port));
+}
+
+void port_byte_out(unsigned short port, unsigned char data) {
+    // both regs are C vars, nothing is returned, so no '=' in asm syntax
+    // comma because two vars in input area and none in return area
+    __asm__("out %%al, %%dx" : : "a" (data), "d" (port));
+}
+
+unsigned short port_word_in(unsigned short port) {
+    unsigned short result;
+    __asm__("in %%dx, %%ax" : "=a" (result) : "d" (port));
+    return result;
+}
+
+void port_word_out(unsigned short port, unsigned short data) {
+    __asm__("out %%ax, %%dx" : : "a" (data), "d" (port));
+}

src/kernel/print.c

@@ -1,5 +1,5 @@
-#include "print.h"
-#include "./platform/ports.h"
+#include <shade/print.h>
+#include <shade/platform/ports.h>
 
 int row = 0;
 int col = 0;
@@ -87,10 +87,10 @@ void print_set_color(char foreground, char background) {
 
 void set_cursor_pos(int col, int row) {
    int offset = col + NUM_COLS * row;
-   outb(REG_SCREEN_CTRL, 14);
-   outb(REG_SCREEN_DATA, (unsigned char)(offset >> 8));
-   outb(REG_SCREEN_CTRL, 15);
-   outb(REG_SCREEN_DATA, (unsigned char)(offset & 0xff)); 
+   port_byte_out(REG_SCREEN_CTRL, 14);
+   port_byte_out(REG_SCREEN_DATA, (unsigned char)(offset >> 8));
+   port_byte_out(REG_SCREEN_CTRL, 15);
+   port_byte_out(REG_SCREEN_DATA, (unsigned char)(offset & 0xff)); 
 }
 
 void kernel_msg_ok(char* msg) {

src/kernel/util.c

@@ -1,4 +1,4 @@
-#include "util.h"
+#include <shade/util.h>
 
 void memcpy(char *source, char *dest, int nbytes) {
     int i;

src/libc/strings.c

@@ -1,4 +1,4 @@
-#include "strings.h"
+#include <strings.h>
 #include <stddef.h>
 
 void itoa(int n, char str[]) {

src/linker.ld

@@ -1,23 +1,30 @@
-
 ENTRY(entry_x86)
 
-SECTIONS
-{
+SECTIONS {
     . = 1M;
 
-	.boot :
-	{
-		KEEP(*(.mb2_header))
-	}
-
-	.text :
+    .text BLOCK(4K) : ALIGN(4K)
     {
+        *(.mb2_header)
         *(.text)
     }
 
-	.idt BLOCK(0x1000) : ALIGN(0x1000)
+    /* Read-only data. */
+	.rodata BLOCK(4K) : ALIGN(4K)
 	{
-		_idt = .;
-		. = . + 0x1000;
+		*(.rodata)
+	}
+ 
+	/* Read-write data (initialized) */
+	.data BLOCK(4K) : ALIGN(4K)
+	{
+		*(.data)
+	}
+ 
+	/* Read-write data (uninitialized) and stack */
+	.bss BLOCK(4K) : ALIGN(4K)
+	{
+		*(COMMON)
+		*(.bss)
 	}
 }