feature: print_stack working (dont use opti flags, else the stack is broken)

Makefile

@@ -3,9 +3,9 @@ NAME := bozOS
 AS := i386-elf-as
 ASFLAGS := 
 CC := i386-elf-gcc
-CFLAGS := -std=gnu99 -ffreestanding -O2 -Wall -Wextra -iquotelibbozo/headers -iquoteheaders -MMD -g
+CFLAGS := -std=gnu99 -ffreestanding -Wall -Wextra -iquotelibbozo/headers -iquoteheaders -MMD -fno-omit-frame-pointer -g
 LD := $(CC)
-LDFLAGS := -T boot/linker.ld -ffreestanding -O2 -nostdlib
+LDFLAGS := -T boot/linker.ld -ffreestanding -nostdlib
 LIBS := -L libbozo/build/ -lbozo -lgcc
 
 SSRC := $(shell find src -name '*.s')

headers/debug.h

@@ -0,0 +1,8 @@
+#pragma once
+
+#include <stdint.h>
+
+struct stackframe {
+	struct stackframe *ebp;
+	uint32_t eip;
+};

headers/gdt.h

@@ -3,30 +3,30 @@
 #include <stdint.h>
 
 #define GDT_ADDRESS 0x00000800
-#define GDT_SIZE 7
+#define GDT_SIZE    7
 
 // https://wiki.osdev.org/Global_Descriptor_Table#GDTR
 struct gdt_descriptor {
-    uint16_t size;
-    uint32_t base;
+	uint16_t size;
+	uint32_t base;
 } __attribute__((packed));
 
-void initGdt();
+void init_gdt();
 
 #define GDT_FLAG_64BIT_MODE 0b0010
 #define GDT_FLAG_32BIT_MODE 0b0100
-#define GDT_FLAG_PAGE_MODE 0b1000
-#define GDT_FLAG_BYTE_MODE 0b1000
+#define GDT_FLAG_PAGE_MODE  0b1000
+#define GDT_FLAG_BYTE_MODE  0b1000
 
-#define GDT_ACCESS_P_VALID 0b10000000
-#define GDT_ACCESS_DPL_KERNEL_MODE 0b00000000
-#define GDT_ACCESS_DPL_USER_MODE   0b01100000
-#define GDT_ACCESS_S_CODE_OR_DATA 0b00010000
-#define GDT_ACCESS_S_SYSTEM_SEGMENT 0b00010000
-#define GDT_ACCESS_E_EXECUTABLE 0b00001000
-#define GDT_ACCESS_E_NOT_EXECUTABLE 0b00000000
-#define GDT_ACCESS_DC_CONFORM 0b00000100 		// TODO UNDERSTAND THIS BIT
-#define GDT_ACCESS_DC_NOT_CONFORM 0b00000000
+#define GDT_ACCESS_P_VALID                                0b10000000
+#define GDT_ACCESS_DPL_KERNEL_MODE                        0b00000000
+#define GDT_ACCESS_DPL_USER_MODE                          0b01100000
+#define GDT_ACCESS_S_CODE_OR_DATA                         0b00010000
+#define GDT_ACCESS_S_SYSTEM_SEGMENT                       0b00010000
+#define GDT_ACCESS_E_EXECUTABLE                           0b00001000
+#define GDT_ACCESS_E_NOT_EXECUTABLE                       0b00000000
+#define GDT_ACCESS_DC_CONFORM                             0b00000100 // TODO UNDERSTAND THIS BIT
+#define GDT_ACCESS_DC_NOT_CONFORM                         0b00000000
 #define GDT_ACCESS_RW_READABLE_FOR_CODE_WRITABLE_FOR_DATA 0b00000010
-#define GDT_ACCESS_A_ACCESSED 0b00000001
-#define GDT_ACCESS_A_NOT_ACCESSED 0b00000000
+#define GDT_ACCESS_A_ACCESSED                             0b00000001
+#define GDT_ACCESS_A_NOT_ACCESSED                         0b00000000

headers/shell.h

@@ -48,6 +48,7 @@ typedef enum {
 	REBOOT,
 	POWEROFF,
 	HALT,
+	STACK,
 	ECHO,
 	COLOR,
 	MERDELLA,
@@ -57,3 +58,4 @@ typedef enum {
 void reboot(void);
 void halt(void);
 void shell_init(void);
+void print_stack(void);

src/debug/print_stack.c

@@ -0,0 +1,13 @@
+#include "debug.h"
+#include "kprintf.h"
+
+void print_stack(void)
+{
+	struct stackframe *stack =
+	    (struct stackframe *)__builtin_frame_address(0);
+
+	while (stack) {
+		kprintf(0, "stack->ebp: %d\n", stack->ebp);
+		stack = stack->ebp;
+	}
+}

src/gdt/gdt.c

@@ -34,10 +34,10 @@ static void set_gdt_entry_value(uint8_t *target, uint32_t base, uint32_t limit,
 	target[6] |= (granularity << 4);
 }
 
-void initGdt(void)
+void init_gdt(void)
 {
 	gdtr->size = 8 * GDT_SIZE - 1;
-	gdtr->base = (uint32_t)&gdt_entries;
+	gdtr->base = (uint32_t)&gdt_entries[0];
 
 	set_gdt_entry_value(gdt_entries + 0x00, 0, 0, 0, 0); // Null segment
 
@@ -58,7 +58,7 @@ void initGdt(void)
 		GDT_ACCESS_A_ACCESSED,
 	    GDT_FLAG_32BIT_MODE | GDT_FLAG_PAGE_MODE); // Kernel data
 	set_gdt_entry_value(
-	    gdt_entries + 0x18, 0, 0x0,
+	    gdt_entries + 0x18, 0, 0xFFFFF,
 	    GDT_ACCESS_P_VALID | GDT_ACCESS_DPL_KERNEL_MODE |
 		GDT_ACCESS_S_CODE_OR_DATA | GDT_ACCESS_E_NOT_EXECUTABLE |
 		GDT_ACCESS_DC_CONFORM |

src/kernel.c

@@ -24,6 +24,6 @@ void kernel_main(void)
 	/* Initialize terminal interface */
 	terminal_initialize();
 
-	initGdt();
+	init_gdt();
 	shell_init();
 }

src/shell/exec.c

@@ -29,6 +29,8 @@ static CMD_TOK find_command(char *line)
 		command = POWEROFF;
 	else if (!strcmp(line, "halt"))
 		command = HALT;
+	else if (!strcmp(line, "stack"))
+		command = STACK;
 	else if (!strcmp(line, "echo"))
 		command = ECHO;
 	else if (!strcmp(line, "color"))
@@ -95,6 +97,9 @@ void shell_init(void)
 		case HALT:
 			halt();
 			break;
+		case STACK:
+			print_stack();
+			break;
 		case ECHO:
 			kprintf(0, "echoing\n");
 			break;

src/shell/power.c

@@ -27,8 +27,8 @@ void reboot(void)
 	} while (check_flag(tmp, KBD_BIT_UDATA));
 	outb(KBD_INTERFACE, KBD_RESET); /* pulse CPU reset line */
 loop:
-	asm volatile("hlt"); /* if that didn't work, halt the CPU */
-	goto loop;           /* if a NMI is received, halt again */
+	asm volatile("hlt");
+	goto loop;
 }
 
 void halt(void)