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2 commits

Author SHA1 Message Date
Jan-Pieter Baert
f9dcb7a5b7
Refactor the kernel files for the new terminal implementation 2020-01-28 02:16:53 +01:00
Jan-Pieter Baert
dea250ee13
Refactor implementation for terminal using states 2020-01-28 02:16:18 +01:00
5 changed files with 253 additions and 196 deletions

View file

@ -11,14 +11,8 @@ To compile, you need:
- `nasm` for compiling the bootloader
- `qemu-system-i386` for emulating (`qemu-system-x86_64` will probably work too, but that is not directly supported)
More information about installing a cross compiler can be found [here](https://wiki.osdev.org/GCC_Cross-Compiler#The_Build).
If you run `make bin`, it will generate `target/boot.bin`, this is a binary file layed out as described in [the docs](docs/bootloader.md). To burn it on a USB drive, simply `dd if=target/boot.bin of=/dev/sdb` and the drive is bootable and contains an SFS filesystem with the files in `filesystem/`.
In case there are errors in the bootloader you can use `make compile_kernel` to only compile the kernel.
To run TABS in the qemu simulator run `make run`.
## Bootloader
The bootloader is self-written, based on articles on [the OSDev wiki](https://wiki.osdev.org/). It's a single stage, ELF-loading bootloader in the most basic way possible.

View file

@ -21,60 +21,65 @@ __attribute__((interrupt)) void NAME (interrupt_frame* frame, uint32_t err_code)
bsod(frame, STR, err_code); \
}
terminal_state state;
void exception_set_terminal_state(terminal_state* s){
terminal_state_copy(s,&state);
}
void bsod(interrupt_frame* frame, char* err_msg, int32_t err_code) {
terminal_initialize();
terminal_writestring("An exception occured: ");
terminal_writestring(err_msg);
terminal_write_str(&state,"An exception occured: ");
terminal_write_str(&state,err_msg);
if(err_code != -1) {
terminal_writestring(" (error code = 0x");
terminal_writeint(err_code, 16);
terminal_writestring(")");
terminal_write_str(&state," (error code = 0x");
terminal_write_int(&state,err_code, 16);
terminal_write_str(&state,")");
}
terminal_writestring("\nHere's what we know:\n");
terminal_writestring("eip = 0x");
terminal_writeint(frame->eip, 16);
terminal_writestring("\ncs = 0x");
terminal_writeint(frame->cs, 16);
terminal_writestring("\neflags = 0b");
terminal_writeint(frame->eflags, 2);
terminal_writestring("\n(");
terminal_write_str(&state,"\nHere's what we know:\n");
terminal_write_str(&state,"eip = 0x");
terminal_write_int(&state,frame->eip, 16);
terminal_write_str(&state,"\ncs = 0x");
terminal_write_int(&state,frame->cs, 16);
terminal_write_str(&state,"\neflags = 0b");
terminal_write_int(&state,frame->eflags, 2);
terminal_write_str(&state,"\n(");
terminal_writestring((0x0001 & frame->eflags) != 0 ? "NC,": "CY,");
terminal_writestring((0x0004 & frame->eflags) != 0 ? "PE,": "PO,");
terminal_writestring((0x0010 & frame->eflags) != 0 ? "AC,": "NA,");
terminal_writestring((0x0040 & frame->eflags) != 0 ? "ZR,": "NZ,");
terminal_writestring((0x0080 & frame->eflags) != 0 ? "NG,": "PL,");
terminal_writestring("TF:");
terminal_writeint((0x0100 & frame->eflags) >> 8, 2);
terminal_putchar(',');
terminal_writestring((0x0200 & frame->eflags) != 0 ? "EI,": "DI,");
terminal_writestring((0x0400 & frame->eflags) != 0 ? "DN,": "UP,");
terminal_writestring((0x0800 & frame->eflags) != 0 ? "OV,": "NV,");
terminal_writestring("IOPL:");
terminal_writeint((0x3000 & frame->eflags) >> 12, 10);
terminal_putchar(',');
terminal_writestring("NT:");
terminal_writeint((0x4000 & frame->eflags) >> 14, 2);
terminal_putchar(',');
terminal_writestring("RF:");
terminal_writeint((0x0001000 & frame->eflags) >> 16, 2);
terminal_putchar(',');
terminal_writestring("VM:");
terminal_writeint((0x0002000 & frame->eflags) >> 17, 2);
terminal_putchar(',');
terminal_writestring("AC:");
terminal_writeint((0x0004000 & frame->eflags) >> 18, 2);
terminal_putchar(',');
terminal_writestring("VIF:");
terminal_writeint((0x0008000 & frame->eflags) >> 19, 2);
terminal_putchar(',');
terminal_writestring("VIP:");
terminal_writeint((0x0010000 & frame->eflags) >> 20, 2);
terminal_putchar(',');
terminal_writestring("ID:");
terminal_writeint((0x0020000 & frame->eflags) >> 21, 2);
terminal_putchar(')');
terminal_write_str(&state,(0x0001 & frame->eflags) != 0 ? "NC,": "CY,");
terminal_write_str(&state,(0x0004 & frame->eflags) != 0 ? "PE,": "PO,");
terminal_write_str(&state,(0x0010 & frame->eflags) != 0 ? "AC,": "NA,");
terminal_write_str(&state,(0x0040 & frame->eflags) != 0 ? "ZR,": "NZ,");
terminal_write_str(&state,(0x0080 & frame->eflags) != 0 ? "NG,": "PL,");
terminal_write_str(&state,"TF:");
terminal_write_int(&state,(0x0100 & frame->eflags) >> 8, 2);
terminal_write_char(&state,',');
terminal_write_str(&state,(0x0200 & frame->eflags) != 0 ? "EI,": "DI,");
terminal_write_str(&state,(0x0400 & frame->eflags) != 0 ? "DN,": "UP,");
terminal_write_str(&state,(0x0800 & frame->eflags) != 0 ? "OV,": "NV,");
terminal_write_str(&state,"IOPL:");
terminal_write_int(&state,(0x3000 & frame->eflags) >> 12, 10);
terminal_write_char(&state,',');
terminal_write_str(&state,"NT:");
terminal_write_int(&state,(0x4000 & frame->eflags) >> 14, 2);
terminal_write_char(&state,',');
terminal_write_str(&state,"RF:");
terminal_write_int(&state,(0x0001000 & frame->eflags) >> 16, 2);
terminal_write_char(&state,',');
terminal_write_str(&state,"VM:");
terminal_write_int(&state,(0x0002000 & frame->eflags) >> 17, 2);
terminal_write_char(&state,',');
terminal_write_str(&state,"AC:");
terminal_write_int(&state,(0x0004000 & frame->eflags) >> 18, 2);
terminal_write_char(&state,',');
terminal_write_str(&state,"VIF:");
terminal_write_int(&state,(0x0008000 & frame->eflags) >> 19, 2);
terminal_write_char(&state,',');
terminal_write_str(&state,"VIP:");
terminal_write_int(&state,(0x0010000 & frame->eflags) >> 20, 2);
terminal_write_char(&state,',');
terminal_write_str(&state,"ID:");
terminal_write_int(&state,(0x0020000 & frame->eflags) >> 21, 2);
terminal_write_char(&state,')');
for(;;) {
asm("hlt");
@ -104,4 +109,4 @@ EXCEPTION_HANDLER_NO_ERR(simd_fp_exception_handler, "SIMD floating point excepti
EXCEPTION_HANDLER_NO_ERR(virtualization_exception_handler, "Virtualization exception");
EXCEPTION_HANDLER_NO_ERR(security_exception_handler, "Security exception");
#endif //EXCEPTION_C
#endif //EXCEPTION_C

View file

@ -25,22 +25,27 @@ static inline bool are_interrupts_enabled() {
return flags & (1 << 9);
}
void kernel_main(void)
void kernel_main(void)
{
/* Initialize terminal interface */
terminal_initialize();
terminal_state state;
terminal_initialize_state(&state);
terminal_putchar('H');
terminal_putchar('e');
terminal_putchar('l');
terminal_putchar('l');
terminal_putchar('o');
terminal_setcolor(vga_entry_color(VGA_COLOR_GREEN, VGA_COLOR_BLACK));
terminal_writestring(" kernel");
terminal_setcolor(vga_entry_color(VGA_COLOR_LIGHT_GREY, VGA_COLOR_BLACK));
terminal_writestring(" World!\n");
terminal_writestring("Newlines!\n");
terminal_set_color(&state, VGA_COLOR_BLACK, VGA_COLOR_RED);
terminal_write_char(&state, 'H');
terminal_set_color(&state, VGA_COLOR_BLACK, VGA_COLOR_GREEN);
terminal_write_char(&state, 'e');
terminal_set_color(&state, VGA_COLOR_BLACK, VGA_COLOR_BLUE);
terminal_write_char(&state, 'l');
terminal_set_color(&state, VGA_COLOR_BLACK, VGA_COLOR_MAGENTA);
terminal_write_char(&state, 'l');
terminal_set_color(&state, VGA_COLOR_BLACK, VGA_COLOR_WHITE);
terminal_write_char(&state, 'o');
terminal_set_color(&state, VGA_COLOR_GREEN, VGA_COLOR_WHITE);
terminal_write_str(&state," kernel");
terminal_set_color(&state, VGA_COLOR_LIGHT_GREY, VGA_COLOR_BLACK);
terminal_write_str(&state," World!\n");
terminal_write_str(&state,"Newlines!\n");
char* memory_str = alloc(sizeof(char) * 7);
for (int i = 0; i < 6; i++) {
@ -54,14 +59,16 @@ void kernel_main(void)
}
management_str[13] = 0;
terminal_writestring(memory_str);
terminal_writestring(management_str);
/* terminal_write_str(&state,memory_str); */
/* terminal_write_str(&state,management_str); */
terminal_writestring((are_interrupts_enabled())? "Interrupts!\n": "No interrupts :(\n");
terminal_write_str(&state, (are_interrupts_enabled())? "Interrupts!\n": "No interrupts :(\n");
shell_set_terminal_state(&state);
exception_set_terminal_state(&state);
interrupt_init();
for(;;) {
shell_step();
}
}
}

View file

@ -11,31 +11,36 @@
char buffer[SHELL_CMD_BUFFER_SIZE];
int buffer_idx = 0;
terminal_state state;
void shell_set_terminal_state(terminal_state* s){
terminal_state_copy(s,&state);
}
int echo(char* input) {
terminal_writestring(input);
terminal_putchar('\n');
terminal_write_str(&state,input);
terminal_write_char(&state,'\n');
return 0;
}
int hello(char* unused) {
terminal_writestring("Hello, world!\n");
terminal_write_str(&state,"Hello, world!\n");
return 0;
}
int cls(char* unused) {
terminal_initialize();
terminal_clear_state(&state);
return 0;
}
int get_gdt(char* unused) {
gdt_desc desc = {2,2};
sgdt(&desc);
terminal_writestring("limit = ");
terminal_writeint(desc.limit, 10);
terminal_writestring("\nbase = 0x");
terminal_writeint(desc.base, 16);
terminal_putchar('\n');
terminal_write_str(&state,"limit = ");
terminal_write_int(&state,desc.limit, 10);
terminal_write_str(&state,"\nbase = 0x");
terminal_write_int(&state,desc.base, 16);
terminal_write_char(&state,'\n');
gdt_entry* entries = (gdt_entry*) desc.base;
int num_entries = (desc.limit+1) / 8;
@ -46,79 +51,78 @@ int get_gdt(char* unused) {
uint8_t flags = (entry.flags_limit_higher >> 4);
bool is_data = ((entry.access_byte & 0b00001000) >> 3) == 0;
//terminal_writestring("\nEntry ");
//terminal_writeint(entry_num, 10);
terminal_writestring("base = 0x");
terminal_writeint(base, 16);
terminal_writestring("\nlimit = 0x");
terminal_writeint(limit, 16);
terminal_writestring("\nflags = 0b");
terminal_writeint((entry.flags_limit_higher >> 4), 2);
//terminal_write_str(&state,"\nEntry ");
//terminal_write_int(&state,entry_num, 10);
terminal_write_str(&state,"base = 0x");
terminal_write_int(&state,base, 16);
terminal_write_str(&state,"\nlimit = 0x");
terminal_write_int(&state,limit, 16);
terminal_write_str(&state,"\nflags = 0b");
terminal_write_int(&state,(entry.flags_limit_higher >> 4), 2);
if ((flags & 0b1000) == 0) {
terminal_writestring(" (byte granularity");
terminal_write_str(&state," (byte granularity");
} else {
terminal_writestring(" (page granularity");
terminal_write_str(&state," (page granularity");
}
if ((flags & 0b0100) == 0) {
terminal_writestring(", 16 bit)");
terminal_write_str(&state,", 16 bit)");
} else {
terminal_writestring(", 32 bit)");
terminal_write_str(&state,", 32 bit)");
}
terminal_writestring("\naccess = 0b");
terminal_writeint(entry.access_byte, 2);
terminal_writestring(" (ring ");
terminal_writeint((entry.access_byte & 0b01100000) >> 5, 10);
terminal_write_str(&state,"\naccess = 0b");
terminal_write_int(&state,entry.access_byte, 2);
terminal_write_str(&state," (ring ");
terminal_write_int(&state,(entry.access_byte & 0b01100000) >> 5, 10);
if ((entry.access_byte & 0b00010000) == 0) {
terminal_writestring(", System");
terminal_write_str(&state,", System");
}
if (is_data) {
terminal_writestring(", Data");
terminal_write_str(&state,", Data");
if((entry.access_byte & 0b00000100) == 0) {
terminal_writestring(" (growing up, ");
terminal_write_str(&state," (growing up, ");
} else {
terminal_writestring(" (growing down, ");
terminal_write_str(&state," (growing down, ");
}
if((entry.access_byte & 0b00000010) == 0) {
terminal_writestring("r--)");
terminal_write_str(&state,"r--)");
} else {
terminal_writestring("rw-)");
terminal_write_str(&state,"rw-)");
}
} else {
terminal_writestring(", Code");
terminal_write_str(&state,", Code");
if((entry.access_byte & 0b00000100) == 0) {
terminal_writestring(" (non-conforming, ");
terminal_write_str(&state," (non-conforming, ");
} else {
terminal_writestring(" (conforming, ");
terminal_write_str(&state," (conforming, ");
}
if((entry.access_byte & 0b00000010) == 0) {
terminal_writestring("--x)");
terminal_write_str(&state,"--x)");
} else {
terminal_writestring("r-x)");
terminal_write_str(&state,"r-x)");
}
}
terminal_writestring(")\n");
terminal_write_str(&state,")\n");
}
return 0;
}
int ree(char* unused) {
terminal_initialize();
terminal_putchar('R');
terminal_write_char(&state,'R');
for (int i = 1; i < VGA_WIDTH * VGA_HEIGHT; i++) {
terminal_putchar('e');
terminal_write_char(&state,'e');
}
return 0;
}
// TODO This is ugly, fix this
// TODO This is ugly, fix this
const char* shell_commands_strings[] = {
"echo",
"hello",
@ -167,7 +171,7 @@ void shell_step() {
char curr_char = getchar();
if (curr_char == '\n') {
terminal_putchar(curr_char);
terminal_write_char(&state,curr_char);
buffer[buffer_idx] = 0;
int result = run_command(buffer);
for (int i = 0; i < SHELL_CMD_BUFFER_SIZE; i++) {
@ -176,19 +180,19 @@ void shell_step() {
buffer_idx = 0;
if (result == -1) {
terminal_writestring("No such command\n");
terminal_write_str(&state,"No such command\n");
}
} else if (curr_char == 0x08) {
if (buffer_idx != 0) {
buffer_idx--;
buffer[buffer_idx] = 0;
terminal_putchar(curr_char);
terminal_write_char(&state,curr_char);
}
} else {
buffer[buffer_idx] = curr_char;
buffer_idx++;
terminal_putchar(curr_char);
terminal_write_char(&state,curr_char);
}
}
#endif //SHELL_C
#endif //SHELL_C

View file

@ -5,8 +5,11 @@
#include <stddef.h>
#include <stdint.h>
static const size_t VGA_WIDTH = 80;
static const size_t VGA_HEIGHT = 25;
#define VGA_WIDTH 80
#define VGA_HEIGHT 25
#define MAX_ENTRIES (VGA_HEIGHT*VGA_WIDTH)
#define TERMINAL_BUFFER_START 0xB8000
#define BLANK_CHAR ' '
/* Hardware text mode color constants. */
enum vga_color {
@ -28,83 +31,127 @@ enum vga_color {
VGA_COLOR_WHITE = 15,
};
size_t terminal_row;
size_t terminal_column;
uint8_t terminal_color;
uint16_t* terminal_buffer;
typedef struct terminal_entry{
enum vga_color bg_color;
enum vga_color fg_color;
char value;
} terminal_entry;
uint8_t vga_entry_color(enum vga_color fg, enum vga_color bg) {
return fg | bg << 4;
typedef struct terminal_state{
terminal_entry entries[MAX_ENTRIES];
int position;
enum vga_color bg_color, fg_color;
} terminal_state;
/* Clear the terminal with only blank spaces */
void __terminal_clear(terminal_state* state){
uint16_t* terminal_buffer = (uint16_t*) TERMINAL_BUFFER_START;
uint16_t empty_color = VGA_COLOR_BLACK | VGA_COLOR_GREEN << 4;
for(size_t y=0;y<VGA_HEIGHT;++y)
for(size_t x=0;x<VGA_WIDTH;++x){
size_t index = y * VGA_WIDTH + x;
terminal_buffer[index] = (uint16_t) ((unsigned char)BLANK_CHAR) | (uint16_t) empty_color << 8;
}
}
uint16_t vga_entry(unsigned char uc, uint8_t color) {
return (uint16_t) uc | (uint16_t) color << 8;
/* Initialise a state, i.e. put every char on blank and the default color everywhere */
void terminal_initialize_state(terminal_state* state){
state->position=0;
state->bg_color = VGA_COLOR_BLACK;
state->fg_color = VGA_COLOR_WHITE;
for(size_t y=0;y<VGA_HEIGHT;++y)
for(size_t x=0;x<VGA_WIDTH;++x){
size_t index = y * VGA_WIDTH + x;
state->entries[index].value = BLANK_CHAR;
}
__terminal_clear(state);
}
size_t strlen(const char* str) {
/* Copy the state from one to the other */
void terminal_state_copy(terminal_state* from, terminal_state* to){
to->position=from->position;
to->bg_color = from->bg_color;
to->fg_color = from->fg_color;
for(size_t y=0;y<VGA_HEIGHT;++y)
for(size_t x=0;x<VGA_WIDTH;++x){
size_t index = y * VGA_WIDTH + x;
to->entries[index].value = from->entries[index].value;
}
}
/* This function will update the terminal buffer with the given state */
void terminal_update(terminal_state *state){
__terminal_clear(state);
uint16_t* terminal_buffer = (uint16_t*) TERMINAL_BUFFER_START;
for(size_t y=0;y<VGA_HEIGHT;++y)
for(size_t x=0;x<VGA_WIDTH;++x){
size_t index = y * VGA_WIDTH + x;
terminal_entry entry = state->entries[index];
uint8_t color = entry.fg_color | entry.bg_color << 4;
terminal_buffer[index] = (uint16_t) ((unsigned char)entry.value) | (uint16_t) color << 8;
}
}
/* Update the background color */
void __terminal_set_bg_color(terminal_state* state, enum vga_color color){
state->bg_color = color;
}
/* Update the foreground color */
void __terminal_set_fg_color(terminal_state* state, enum vga_color color){
state->fg_color = color;
}
/* Update the color */
void terminal_set_color(terminal_state* state, enum vga_color bg_color, enum vga_color fg_color){
__terminal_set_bg_color(state, bg_color);
__terminal_set_fg_color(state, fg_color);
}
/* Write a char to the state */
void __terminal_put_char(terminal_state *state, char c){
size_t pos = state->position;
terminal_entry entry;
/* If there is a new line, keep going until the end of the line (with blank space in black) */
if(c == '\n'){
entry.bg_color = VGA_COLOR_BLACK;
entry.fg_color = VGA_COLOR_BLACK;
entry.value = BLANK_CHAR;
while(pos % VGA_WIDTH){
state->entries[pos] = entry;
++pos;
}
state->position = (pos % MAX_ENTRIES);
}
else{
entry.bg_color = state->bg_color;
entry.fg_color = state->fg_color;
entry.value = c;
state->entries[pos] = entry;
state->position = ((pos+1) % MAX_ENTRIES);
}
}
/* Write a char to the state and run an update */
void terminal_write_char(terminal_state *state, const char c){
__terminal_put_char(state, c);
terminal_update(state);
}
/* Write a string to the state and run an update */
void terminal_write_str(terminal_state *state, const char* str){
size_t len = 0;
while (str[len])
len++;
return len;
while (str[len]) {
__terminal_put_char(state, str[len]);
++len;
}
terminal_update(state);
}
void terminal_initialize(void) {
terminal_row = 0;
terminal_column = 0;
terminal_color = vga_entry_color(VGA_COLOR_LIGHT_GREY, VGA_COLOR_BLACK);
terminal_buffer = (uint16_t*) 0xB8000;
for (size_t y = 0; y < VGA_HEIGHT; y++) {
for (size_t x = 0; x < VGA_WIDTH; x++) {
const size_t index = y * VGA_WIDTH + x;
terminal_buffer[index] = vga_entry(' ', terminal_color);
}
}
}
void terminal_setcolor(uint8_t color) {
terminal_color = color;
}
void terminal_putentryat(char c, uint8_t color, size_t x, size_t y) {
const size_t index = y * VGA_WIDTH + x;
terminal_buffer[index] = vga_entry(c, color);
}
void terminal_putchar(char c) {
if (c == '\n') {
terminal_column = 0;
terminal_row++;
return;
}
if (c == 0x08) {
terminal_putentryat(' ', terminal_color, terminal_column, terminal_row);
if (terminal_column == 0) {
if(terminal_row != 0) {
terminal_row--;
terminal_column = VGA_WIDTH - 1;
}
} else {
terminal_column--;
}
terminal_putentryat(' ', terminal_color, terminal_column, terminal_row);
return;
}
terminal_putentryat(c, terminal_color, terminal_column, terminal_row);
if (++terminal_column == VGA_WIDTH) {
terminal_column = 0;
if (++terminal_row == VGA_HEIGHT)
terminal_row = 0;
}
}
void terminal_write(const char* data, size_t size) {
for (size_t i = 0; i < size; i++)
terminal_putchar(data[i]);
}
void terminal_writestring(const char* data) {
terminal_write(data, strlen(data));
/* Clear the terminal en reset the state to the initial state */
void terminal_clear_state(terminal_state* state){
__terminal_clear(state);
terminal_initialize_state(state);
}
char* itoa(unsigned int value, char* result, int base) {
@ -129,10 +176,10 @@ char* itoa(unsigned int value, char* result, int base) {
return result;
}
void terminal_writeint(int number, int base) {
void terminal_write_int(terminal_state* state,int number, int base) {
char* result = "XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX";
itoa(number, result, base);
terminal_writestring(result);
terminal_write_str(state, result);
}
#endif //TERMINAL_C
#endif //TERMINAL_C