From 20ab9e1d6ea4ab331de2319a1a3a6e512a8caa4b Mon Sep 17 00:00:00 2001
From: Rick Rongen <rickrongen@outlook.com>
Date: Sun, 21 Mar 2021 17:34:38 +0100
Subject: [PATCH] feat: gdt, attributes move, reorder

Added late gdt setup with initial tss
Moved attributes to include root
Reordered some imports
---
 include/attributes.h           |  19 ++++
 include/elf.h                  |   6 +-
 include/myke/attributes.h      |  19 ----
 include/myke/cpu/gdt.h         |  10 ++
 include/myke/cpu/idt.h         |   6 +-
 include/myke/driver.h          |   2 +-
 include/myke/drivers/pci/pci.h |   6 +-
 include/myke/libk/libk.h       |   6 +-
 include/myke/libk/syscall.h    |   4 +-
 include/myke/util/power.h      |   4 +-
 kernel/command.c               |  16 +--
 kernel/cpu/gdt.S               |  18 ++++
 kernel/cpu/gdt.c               | 192 +++++++++++++++++++++++++++++++++
 kernel/debug/debug.c           |   6 +-
 kernel/drivers/pci/ide.c       |  19 ++--
 kernel/drivers/pci/pci.c       |   5 +-
 kernel/fs/blockdev.c           |  12 +--
 kernel/fs/fat.c                |  26 ++---
 kernel/fs/mbr.c                |  12 +--
 kernel/fs/ustar.c              |   9 +-
 kernel/kernel.c                |  11 +-
 kernel/libk/kprint.c           |  10 +-
 kernel/libk/libk.c             |   7 +-
 kernel/libk/syscall.c          |   4 +-
 kernel/mem/mem.c               |   8 +-
 kernel/mem/paging.c            |  12 +--
 kernel/tasks/task.c            |  18 ++--
 kernel/util/power.c            |   5 +-
 28 files changed, 351 insertions(+), 121 deletions(-)
 create mode 100644 include/attributes.h
 delete mode 100644 include/myke/attributes.h
 create mode 100644 include/myke/cpu/gdt.h
 create mode 100644 kernel/cpu/gdt.S
 create mode 100644 kernel/cpu/gdt.c

diff --git a/include/attributes.h b/include/attributes.h
new file mode 100644
index 0000000..9333903
--- /dev/null
+++ b/include/attributes.h
@@ -0,0 +1,19 @@
+//
+// Created by rick on 24-02-21.
+//
+
+#ifndef NEW_KERNEL_ATTRIBUTES_H
+#define NEW_KERNEL_ATTRIBUTES_H
+
+// generic
+#define att_used __attribute((used))
+
+// function
+#define att_noreturn __attribute((noreturn))
+#define att_cdecl __attribute((cdecl))
+// structure
+#define att_packed __attribute((packed))
+// field
+#define att_aligned(size) __attribute((aligned(size)))
+
+#endif //NEW_KERNEL_ATTRIBUTES_H
diff --git a/include/elf.h b/include/elf.h
index d5a1c94..071a0e7 100644
--- a/include/elf.h
+++ b/include/elf.h
@@ -6,7 +6,7 @@
 #define NEW_KERNEL_ELF_H
 
 #include <sys/types.h>
-#include <myke/attributes.h>
+#include <attributes.h>
 
 #define SHT_NULL        0
 #define SHT_PROGBITS    1
@@ -59,7 +59,7 @@ struct elf32_section_header {
     uint32_t sh_info;
     uint32_t sh_addr_align;
     uint32_t sh_ent_size;
-} packed;
+} att_packed;
 
 struct elf32_symtab_entry {
     uint32_t st_name;
@@ -68,6 +68,6 @@ struct elf32_symtab_entry {
     uint8_t st_info;
     uint8_t st_other;
     uint16_t st_shndx;
-} packed;
+} att_packed;
 
 #endif //NEW_KERNEL_ELF_H
diff --git a/include/myke/attributes.h b/include/myke/attributes.h
deleted file mode 100644
index 9c01876..0000000
--- a/include/myke/attributes.h
+++ /dev/null
@@ -1,19 +0,0 @@
-//
-// Created by rick on 24-02-21.
-//
-
-#ifndef NEW_KERNEL_ATTRIBUTES_H
-#define NEW_KERNEL_ATTRIBUTES_H
-
-// generic
-#define used __attribute((used))
-
-// function
-#define noreturn __attribute((noreturn))
-#define cdecl __attribute((cdecl))
-// structure
-#define packed __attribute((packed))
-// field
-#define at_aligned(size) __attribute((aligned(size)))
-
-#endif //NEW_KERNEL_ATTRIBUTES_H
diff --git a/include/myke/cpu/gdt.h b/include/myke/cpu/gdt.h
new file mode 100644
index 0000000..4c942e8
--- /dev/null
+++ b/include/myke/cpu/gdt.h
@@ -0,0 +1,10 @@
+//
+// Created by rick on 19-03-21.
+//
+
+#ifndef NEW_KERNEL_GDT_H
+#define NEW_KERNEL_GDT_H
+
+void gdt_init();
+
+#endif //NEW_KERNEL_GDT_H
diff --git a/include/myke/cpu/idt.h b/include/myke/cpu/idt.h
index d0b50f1..e35ca03 100644
--- a/include/myke/cpu/idt.h
+++ b/include/myke/cpu/idt.h
@@ -6,7 +6,7 @@
 #ifndef MY_KERNEL_IDT_H
 #define MY_KERNEL_IDT_H
 
-#include <myke/attributes.h>
+#include <attributes.h>
 
 #define KERNEL_CS 0x08
 
@@ -22,12 +22,12 @@ typedef struct {
      * Bits 3-0: bits 1110 = decimal 14 = "32 bit interrupt gate" */
     uint8_t flags;
     uint16_t high_offset; /* Higher 16 bits of handler function address */
-} packed idt_gate_t;
+} att_packed idt_gate_t;
 
 typedef struct {
     uint16_t limit;
     uint32_t base;
-} packed idt_register_t;
+} att_packed idt_register_t;
 
 #define IDT_REGISTERS 256
 
diff --git a/include/myke/driver.h b/include/myke/driver.h
index 8386d51..d5de1d3 100644
--- a/include/myke/driver.h
+++ b/include/myke/driver.h
@@ -5,7 +5,7 @@
 #ifndef NEW_KERNEL_DRIVER_H
 #define NEW_KERNEL_DRIVER_H
 
-#include <myke/attributes.h>
+#include <attributes.h>
 #include <myke/preprocessor_format_zero.h>
 
 #ifndef STRUCT_ALIGNMENT
diff --git a/include/myke/drivers/pci/pci.h b/include/myke/drivers/pci/pci.h
index 39af85d..64126f7 100644
--- a/include/myke/drivers/pci/pci.h
+++ b/include/myke/drivers/pci/pci.h
@@ -8,7 +8,7 @@
 #include <sys/types.h>
 #include <myke/driver.h>
 #include <stdbool.h>
-#include <myke/attributes.h>
+#include <attributes.h>
 
 #define PCI_CLASS_MASS_STORAGE  0x01
 #define PCI_CLASS_BRIDGE        0x06
@@ -190,7 +190,7 @@ typedef union {
         bool fast_b2b_enable: 1;
         bool interrupt_disable: 1;
         uint8_t reserved2: 5;
-    } packed command;
+    } att_packed command;
 } pci_command_register_t;
 
 typedef union {
@@ -209,7 +209,7 @@ typedef union {
         bool received_master_abort: 1;
         bool signaled_system_error: 1;
         bool detected_parity_error: 1;
-    } packed status;
+    } att_packed status;
 } pci_status_register_t;
 
 void pci_print_info();
diff --git a/include/myke/libk/libk.h b/include/myke/libk/libk.h
index 350d8f0..aa5a144 100644
--- a/include/myke/libk/libk.h
+++ b/include/myke/libk/libk.h
@@ -5,7 +5,7 @@
 #ifndef NEW_KERNEL_LIBK_H
 #define NEW_KERNEL_LIBK_H
 
-#include <myke/attributes.h>
+#include <attributes.h>
 #include <stdbool.h>
 
 extern void *_kernel_start;
@@ -17,8 +17,8 @@ bool k_addr_in_kspace(void *addr);
 
 void k_wait_for_interrupt();
 
-void noreturn k_panics(const char *msg);
+void att_noreturn k_panics(const char *msg);
 
-void noreturn k_panic();
+void att_noreturn k_panic();
 
 #endif //NEW_KERNEL_LIBK_H
diff --git a/include/myke/libk/syscall.h b/include/myke/libk/syscall.h
index da2d598..a019b29 100644
--- a/include/myke/libk/syscall.h
+++ b/include/myke/libk/syscall.h
@@ -6,14 +6,14 @@
 #define NEW_KERNEL_SYSCALL_H
 
 #include <sys/types.h>
-#include <myke/attributes.h>
+#include <attributes.h>
 
 #define SYSCALL_START_SCHEDULER 0x01
 #define SYSCALL_YIELD_JOB       0x02
 #define SYSCALL_YIELD_IRQ       0x03
 #define SYSCALL_SUSPEND         0x04
 
-void noreturn syscall_start_scheduler();
+void att_noreturn syscall_start_scheduler();
 
 void syscall_yield_job();
 
diff --git a/include/myke/util/power.h b/include/myke/util/power.h
index 88bfa64..882c1db 100644
--- a/include/myke/util/power.h
+++ b/include/myke/util/power.h
@@ -5,8 +5,8 @@
 #ifndef NEW_KERNEL_POWER_H
 #define NEW_KERNEL_POWER_H
 
-#include <myke/attributes.h>
+#include <attributes.h>
 
-void noreturn power_shutdown();
+void att_noreturn power_shutdown();
 
 #endif //NEW_KERNEL_POWER_H
diff --git a/kernel/command.c b/kernel/command.c
index 444ae8c..c66dd57 100644
--- a/kernel/command.c
+++ b/kernel/command.c
@@ -1,22 +1,22 @@
 //
 // Created by rick on 23-02-21.
 //
-#include <stdio.h>
+#include <attributes.h>
 #include <stdbool.h>
+#include <stdio.h>
 #include <string.h>
 #include <sys/types.h>
+#include <readline/readline.h>
 
 #include <myke/command.h>
-#include <myke/libk/libk.h>
-#include <myke/mem/mem.h>
-#include <myke/mem/malloc.h>
 #include <myke/cpu/timer.h>
-#include <myke/drivers/pci/pci.h>
 #include <myke/drivers/pci/ide.h>
+#include <myke/drivers/pci/pci.h>
 #include <myke/fs/blockdev.h>
 #include <myke/fs/mbr.h>
-#include <readline/readline.h>
-#include <myke/attributes.h>
+#include <myke/libk/libk.h>
+#include <myke/mem/malloc.h>
+#include <myke/mem/mem.h>
 #include <myke/util/power.h>
 
 #ifdef ENABLE_SELF_TEST
@@ -172,7 +172,7 @@ void store_bootloader_info(multiboot_info_t *multiboot_info) {
     }
 }
 
-void noreturn main_loop(void *data) {
+void att_noreturn main_loop(void *data) {
     while (true) {
         char *msg = readline(NULL);
         char *args = strchr(msg, ' ');
diff --git a/kernel/cpu/gdt.S b/kernel/cpu/gdt.S
new file mode 100644
index 0000000..a7d9010
--- /dev/null
+++ b/kernel/cpu/gdt.S
@@ -0,0 +1,18 @@
+.code32
+.extern gdt_ptr
+
+.global _gdt_switch
+_gdt_switch:
+    lgdt gdt_ptr
+    movw $0x10,%ax
+    movw %ax,%ds
+    movw %ax,%es
+    movw %ax,%fs
+    movw %ax,%gs
+    ljmp $0x8, $_gdt_switch_continue
+_gdt_switch_continue:
+    movw $0x2a, %ax // 0x28 + 0x03 = 0x2a
+    ltr %ax
+    ret
+
+
diff --git a/kernel/cpu/gdt.c b/kernel/cpu/gdt.c
new file mode 100644
index 0000000..164af63
--- /dev/null
+++ b/kernel/cpu/gdt.c
@@ -0,0 +1,192 @@
+//
+// Created by rick on 19-03-21.
+//
+#include <attributes.h>
+#include <sys/types.h>
+
+#include <myke/libk/libk.h>
+#include <myke/cpu/gdt.h>
+
+typedef struct gdt {
+    uint32_t base;
+    uint32_t limit;
+    union {
+        uint8_t access_byte;
+        struct {
+            bool accessed: 1;
+            bool read_write: 1; // for executable, if reading is allowed. For Non-exec if writing is allowed
+            // data sector: direction
+            //      grows up(false) or down(true).
+            // executable sector: conforming
+            //      if true higher privilege levels can execute this code (e.g. ring 3 can exec ring 0 code) the privilege level it self is not changed.
+            //      if false, only the specified ring can execute the code
+            bool direction_conforming: 1;
+            bool executable: 1;
+            bool is_sector: 1;
+            uint8_t privilege: 2;
+            bool present: 1;
+        } att_packed;
+    };
+    union {
+        uint8_t flags_byte: 4;
+        struct {
+            uint8_t unused: 2;
+            bool size: 1; // false 16bit, true 32bit
+            bool granularity: 1; // false 1 byte, true 4KiB
+        } att_packed;
+    };
+} gdt_t;
+
+struct tss_ring {
+    uint32_t esp;
+    uint16_t ss;
+    uint16_t: 16; // skipped
+} att_packed;
+
+typedef struct tss {
+    uint16_t link;
+    uint16_t: 16; // skipped
+    struct tss_ring r0;
+    struct tss_ring r1;
+    struct tss_ring r2;
+    struct {
+        uint32_t cr3;
+        uint32_t eip;
+        uint32_t eflags;
+        uint32_t eax;
+        uint32_t ecx;
+        uint32_t edx;
+        uint32_t ebx;
+        uint32_t esp;
+        uint32_t ebp;
+        uint32_t esi;
+        uint32_t edi;
+        uint16_t es;
+        uint16_t: 16;
+        uint16_t cs;
+        uint16_t: 16;
+        uint16_t ss;
+        uint16_t: 16;
+        uint16_t ds;
+        uint16_t: 16;
+        uint16_t fs;
+        uint16_t: 16;
+        uint16_t gs;
+        uint16_t: 16;
+        uint16_t ldtr;
+        uint16_t: 16;
+    } att_packed regs;
+    uint16_t: 16;
+    uint16_t iopb_offset;
+} att_packed tss_t;
+_Static_assert(sizeof(tss_t) == 104, "TSS incorrect size");
+
+typedef struct gdtr {
+    uint16_t size;
+    uint32_t offset;
+} att_packed gdtr_t;
+
+#define num_gdts 5
+
+extern void _gdt_switch();
+
+tss_t tss = {
+        .iopb_offset = sizeof(tss_t),
+        .r0.ss = 0x10,
+};
+
+gdt_t gdts[num_gdts] = {
+        { // 0x08 kernel code
+                .present = true,
+                .base = 0,
+                .limit = 0xFFFFFFFF,
+                .is_sector = true,
+                .size = true,
+                .granularity = true,
+                .executable = true,
+                .read_write = true,
+                .privilege = 0,
+        }, { // 0x10 kernel data
+                .present = true,
+                .base = 0,
+                .limit = 0xFFFFFFFF,
+                .is_sector = true,
+                .size = true,
+                .granularity = true,
+                .executable = false,
+                .read_write = true,
+        }, { // 0x18 user code
+                .present = true,
+                .base = 0,
+                .limit = 0xFFFFFFFF,
+                .privilege = 3,
+                .is_sector = true,
+                .size = true,
+                .granularity = true,
+                .executable = true,
+                .read_write = true,
+        }, { // 0x20 user  data
+                .present = true,
+                .base = 0,
+                .limit = 0xFFFFFFFF,
+                .privilege = 3,
+                .is_sector = true,
+                .size = true,
+                .granularity = true,
+                .executable = true,
+                .read_write = true,
+        }, { // 0x28 tss
+                .base = (uint32_t) &tss,
+                .limit = sizeof(tss_t),
+                .present = true,
+                .executable = true,
+                .accessed = true,
+                .size = true,
+        }
+};
+uint64_t gdt_values[num_gdts + 1] = {0};
+gdtr_t gdt_ptr = {
+        .size = sizeof(uint64_t) * (num_gdts + 1) - 1,
+        .offset = (uint32_t) &gdt_values,
+};
+_Static_assert(sizeof(gdt_ptr) == 6, "GDT PTR incorrect size");
+
+uint64_t gdt_encode(gdt_t *gdt) {
+    // high limit must be full 4k
+    uint64_t limit = gdt->limit;
+    if (limit > 65536 && (limit & 0xFFF) != 0xFFF && !gdt->granularity) {
+        return 0;
+    } else {
+        limit >>= 12;
+    }
+    uint64_t value = 0
+                     | (limit & 0xFFFF)
+                     | ((gdt->base & 0xFFFF) << 16)
+                     | ((uint64_t) ((gdt->base >> 16) & 0xFF) << 32)
+                     | ((uint64_t) (gdt->access_byte) << 40)
+                     | ((limit >> 16) << 48)
+                     | ((uint64_t) (gdt->flags_byte) << 52)
+                     | ((uint64_t) (gdt->base >> 24) << 56);
+    return value;
+}
+
+void gdt_activate() {
+    gdt_values[0] = 0; // first is zero
+    for (int i = 0; i < num_gdts; ++i) {
+        gdt_values[i + 1] = gdt_encode(&gdts[i]);
+        if (gdt_values[i + 1] == 0) {
+            // todo failed to encode
+            k_panics("Failed to encode GDT\n");
+        }
+    }
+    _gdt_switch();
+}
+
+void gdt_init() {
+    // Replace the early gdt with a new one
+    // this one will be extensible and support stuff like TSS
+
+    tss.r0.esp = 0; // todo
+
+    gdt_activate();
+}
\ No newline at end of file
diff --git a/kernel/debug/debug.c b/kernel/debug/debug.c
index 2894bd1..edc6915 100644
--- a/kernel/debug/debug.c
+++ b/kernel/debug/debug.c
@@ -4,11 +4,12 @@
 
 #include <stdio.h>
 #include <string.h>
+#include <stdlib.h>
+#include <elf.h>
 
 #define DEBUG_INIT
 
 #include <myke/debug/debug.h>
-#include <elf.h>
 #include <myke/libk/libk.h>
 #include <myke/libk/kprint.h>
 
@@ -73,7 +74,8 @@ void debug_store_info(struct multiboot_info *info) {
     if (sizeof(struct elf32_section_header) != info->u.elf_sec.size) {
         k_panics("ELF size not correct");
     }
-    elf_headers = (struct elf32_section_header *) info->u.elf_sec.addr;
+    elf_headers = calloc(info->u.elf_sec.num, sizeof(struct elf32_section_header));
+    memcpy(elf_headers, (const void *) info->u.elf_sec.addr, sizeof(struct elf32_section_header) * info->u.elf_sec.num);
     elf_header_cnt = info->u.elf_sec.num;
     debug_find_sections(info->u.elf_sec.shndx);
 }
diff --git a/kernel/drivers/pci/ide.c b/kernel/drivers/pci/ide.c
index b03ffe2..92156d6 100644
--- a/kernel/drivers/pci/ide.c
+++ b/kernel/drivers/pci/ide.c
@@ -3,19 +3,20 @@
 //
 // https://wiki.osdev.org/PCI_IDE_Controller
 
+#include <attributes.h>
 #include <stdbool.h>
+#include <stdio.h>
 #include <stdlib.h>
 #include <sys/types.h>
-#include <stdio.h>
 
-#include <myke/drivers/pci/ide.h>
-#include <myke/debug/debug.h>
-#include <myke/drivers/ports.h>
-#include <myke/libk/kprint.h>
-#include <myke/drivers/pci/pci.h>
-#include <myke/libk/libk.h>
 #include <myke/cpu/timer.h>
+#include <myke/debug/debug.h>
+#include <myke/drivers/pci/ide.h>
+#include <myke/drivers/pci/pci.h>
+#include <myke/drivers/ports.h>
 #include <myke/fs/blockdev.h>
+#include <myke/libk/kprint.h>
+#include <myke/libk/libk.h>
 #include <myke/tasks/locking.h>
 
 #define ATA_SR_BSY     0x80    // Busy
@@ -414,7 +415,7 @@ void ide_register_block_devices() {
     }
 }
 
-uint8_t used ide_pci_validate(const pci_device *device) {
+uint8_t att_used ide_pci_validate(const pci_device *device) {
     if (device->class != PCI_CLASS_MASS_STORAGE
         || device->subclass != PCI_SUB_CLASS_IDE
         || (device->programInterface != 0x8A && device->programInterface != 0x80)) {
@@ -424,7 +425,7 @@ uint8_t used ide_pci_validate(const pci_device *device) {
     return PCI_VALIDATE_OK;
 }
 
-uint8_t used ide_pci_initialize(pci_device *device) {
+uint8_t att_used ide_pci_initialize(pci_device *device) {
 
     if (!ide_pci_init_channels(device)) {
         return PCI_INIT_FAIL;
diff --git a/kernel/drivers/pci/pci.c b/kernel/drivers/pci/pci.c
index 002ec70..29722c6 100644
--- a/kernel/drivers/pci/pci.c
+++ b/kernel/drivers/pci/pci.c
@@ -3,8 +3,9 @@
 //
 // https://wiki.osdev.org/PCI
 
-#include <sys/types.h>
+#include <attributes.h>
 #include <stdio.h>
+#include <sys/types.h>
 
 #include <myke/drivers/pci/pci.h>
 #include <myke/drivers/ports.h>
@@ -44,7 +45,7 @@ pci_device pci_devices[MAX_PCI_DEVICES];
 
 void pci_check_bus(uint8_t bus);
 
-uint8_t used pci_secondary_bus_use(const pci_device *device) {
+uint8_t att_used pci_secondary_bus_use(const pci_device *device) {
     uint8_t secondary_bus = pci_config_read_byte(device->bus, device->slot, device->func,
                                                  PCI_CONFIG_SECONDARY_BUS_NUMBER);
     pci_check_bus(secondary_bus);
diff --git a/kernel/fs/blockdev.c b/kernel/fs/blockdev.c
index d9b3a2a..26b042e 100644
--- a/kernel/fs/blockdev.c
+++ b/kernel/fs/blockdev.c
@@ -2,15 +2,15 @@
 // Created by rick on 06-02-21.
 //
 
+#include <attributes.h>
+#include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
-#include <stdio.h>
 
-#include <myke/libk/libk.h>
-#include <myke/tasks/task.h>
-#include <myke/tasks/locking.h>
-#include <myke/attributes.h>
 #include <myke/fs/blockdev.h>
+#include <myke/libk/libk.h>
+#include <myke/tasks/locking.h>
+#include <myke/tasks/task.h>
 
 #define MAX_BLOCK_DEVS 64
 
@@ -122,7 +122,7 @@ void block_dev_scan() {
     }
 }
 
-void noreturn block_dev_task(void *data) {
+void att_noreturn block_dev_task(void *data) {
     while (true) {
         semaphore_wait(block_semaphore);
         block_dev_scan();
diff --git a/kernel/fs/fat.c b/kernel/fs/fat.c
index 23ff654..f5a91e7 100644
--- a/kernel/fs/fat.c
+++ b/kernel/fs/fat.c
@@ -2,13 +2,13 @@
 // Created by rick on 07-02-21.
 //
 
+#include <attributes.h>
+#include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
-#include <stdio.h>
+#include <sys/types.h>
 
 #include <myke/fs/blockdev.h>
-#include <sys/types.h>
-#include <myke/attributes.h>
 
 #define FAT_TYPE_12 1
 #define FAT_TYPE_16 2
@@ -31,7 +31,7 @@ typedef struct {
         uint16_t heads_sides;
         uint32_t hidden_sectors;
         uint32_t large_total_sectors;
-    } packed bpb;
+    } att_packed bpb;
     union {
         struct {
             uint8_t drive_number;
@@ -40,7 +40,7 @@ typedef struct {
             uint32_t serial;
             uint8_t label[11];
             uint8_t system_id[8];
-        } packed ebr_12_16;
+        } att_packed ebr_12_16;
         struct {
             uint32_t sectors_per_fat;
             uint16_t flags;
@@ -55,21 +55,21 @@ typedef struct {
             uint32_t serial;
             uint8_t label[11];
             uint8_t system_id[8];
-        } packed ebr_32;
+        } att_packed ebr_32;
     };
-} packed fat_bpb;
+} att_packed fat_bpb;
 
 typedef struct {
     uint8_t hours: 5;
     uint8_t minutes: 6;
     uint8_t seconds: 5;
-} packed time_83;
+} att_packed time_83;
 
 typedef struct {
     uint8_t hours: 5;
     uint8_t minutes: 6;
     uint8_t seconds: 5;
-} packed date_83;
+} att_packed date_83;
 
 typedef struct {
     union {
@@ -86,7 +86,7 @@ typedef struct {
             date_83 last_mod_date;
             uint16_t low_first_cluster;
             uint32_t file_size;
-        } packed name_83;
+        } att_packed name_83;
         struct {
             uint8_t order;
             uint16_t text_1[5];
@@ -96,9 +96,9 @@ typedef struct {
             uint16_t text_2[6];
             uint16_t reserved;
             uint16_t text_3[2];
-        } packed long_name;
+        } att_packed long_name;
     };
-} packed fat_directory_entry;
+} att_packed fat_directory_entry;
 
 void print_chars(char *chars, int amount) {
     for (int i = 0; i < amount; ++i) {
@@ -107,7 +107,7 @@ void print_chars(char *chars, int amount) {
     }
 }
 
-uint8_t used fat_check_device(const block_device_t *device, uint8_t *first_sector) {
+uint8_t att_used fat_check_device(const block_device_t *device, uint8_t *first_sector) {
     fat_bpb bpb;
     memcpy((uint8_t *) &bpb, first_sector, sizeof(fat_bpb));
     if (bpb.bpb.sectors_per_fat == 0 || bpb.bpb.sectors_per_cluster == 0) {
diff --git a/kernel/fs/mbr.c b/kernel/fs/mbr.c
index a1567a1..f315df7 100644
--- a/kernel/fs/mbr.c
+++ b/kernel/fs/mbr.c
@@ -2,15 +2,15 @@
 // Created by rick on 06-02-21.
 //
 
+#include <attributes.h>
+#include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
-#include <stdio.h>
 #include <sys/types.h>
 
-#include <myke/fs/mbr.h>
 #include <myke/drivers/pci/ide.h>
 #include <myke/fs/blockdev.h>
-#include <myke/attributes.h>
+#include <myke/fs/mbr.h>
 
 typedef struct {
     uint8_t bootable;
@@ -23,14 +23,14 @@ typedef struct {
     uint16_t ending_cylinder: 10;
     uint32_t start_lba;
     uint32_t num_lbas;
-}  packed mbr_partition_table_entry;
+}  att_packed mbr_partition_table_entry;
 
 typedef struct {
     uint32_t unique_id;
     uint16_t reserved;
     mbr_partition_table_entry entries[4];
     uint8_t signature[2];
-} packed mbr_table;
+} att_packed mbr_table;
 
 typedef struct {
     const block_device_t *device;
@@ -52,7 +52,7 @@ mbr_block_dev_access(const block_device_t *device, uint8_t direction, uint32_t l
     return info->device->access(info->device, direction, actual_lba, sectors, target);
 }
 
-uint8_t used mbr_check_device(const block_device_t *device, uint8_t *first_sector) {
+uint8_t att_used mbr_check_device(const block_device_t *device, uint8_t *first_sector) {
     mbr_table table;
     memcpy((uint8_t *) &table, first_sector + (device->block_size - sizeof(mbr_table)), sizeof(mbr_table));
     if (table.signature[0] != 0x55 && table.signature[1] != 0xAA) { // AA 55 but in little endian
diff --git a/kernel/fs/ustar.c b/kernel/fs/ustar.c
index dc7e5bb..1547a5f 100644
--- a/kernel/fs/ustar.c
+++ b/kernel/fs/ustar.c
@@ -1,12 +1,13 @@
 //
 // Created by rick on 11-03-21.
 //
+#include <attributes.h>
+#include <stdbool.h>
+#include <stdlib.h>
+#include <string.h>
 #include <sys/types.h>
 
 #include <myke/fs/blockdev.h>
-#include <string.h>
-#include <stdbool.h>
-#include <stdlib.h>
 
 typedef struct {
     char filename[100];
@@ -25,7 +26,7 @@ typedef struct {
     uint64_t device_major;
     uint64_t device_minor;
     char prefix[155];
-} packed ustar_sector;
+} att_packed ustar_sector;
 
 typedef struct {
     ustar_sector sector;
diff --git a/kernel/kernel.c b/kernel/kernel.c
index a1a2b01..0dc3cfd 100644
--- a/kernel/kernel.c
+++ b/kernel/kernel.c
@@ -1,9 +1,12 @@
-#include <stdio.h>
+#include <attributes.h>
 #include <multiboot.h>
+#include <stdio.h>
 
 #define DEBUG_INIT
 
+#include <myke/command.h>
 #include <myke/cpu/cpuidx.h>
+#include <myke/cpu/gdt.h>
 #include <myke/cpu/isr.h>
 #include <myke/cpu/timer.h>
 #include <myke/debug/debug.h>
@@ -17,8 +20,6 @@
 #include <myke/libk/syscall.h>
 #include <myke/mem/mem.h>
 #include <myke/tasks/task.h>
-#include <myke/attributes.h>
-#include <myke/command.h>
 
 const int version_major = 0,
         version_minor = 0,
@@ -38,7 +39,7 @@ void init_pci_system() {
     pci_init_drivers();
 }
 
-void noreturn used kmain(multiboot_info_t *multiboot_info, uint32_t mb_name) {
+void att_noreturn att_used kmain(multiboot_info_t *multiboot_info, uint32_t mb_name) {
     // early init
     isr_install();
     vga_clear_screen();
@@ -57,6 +58,8 @@ void noreturn used kmain(multiboot_info_t *multiboot_info, uint32_t mb_name) {
     // initialize memory management
     init_mmap(multiboot_info);
 
+    gdt_init();
+
     // initialize kprint functionality
     kprint_init();
 
diff --git a/kernel/libk/kprint.c b/kernel/libk/kprint.c
index 18d76fd..94e3e70 100644
--- a/kernel/libk/kprint.c
+++ b/kernel/libk/kprint.c
@@ -2,13 +2,13 @@
 // Created by rick on 28-01-21.
 //
 
-#include <string.h>
+#include <attributes.h>
 #include <stdbool.h>
+#include <string.h>
 
-#include <myke/util/stream.h>
-#include <myke/attributes.h>
-#include <myke/tasks/task.h>
 #include <myke/libk/kprint.h>
+#include <myke/tasks/task.h>
+#include <myke/util/stream.h>
 
 #define MAX_HANDLERS 8
 #define STREAM_SIZE (32*1024)
@@ -49,7 +49,7 @@ void kprint_init() {
     kprint_stream = stream_create(STREAM_SIZE);
 }
 
-void noreturn kprint_task(void *_) {
+void att_noreturn kprint_task(void *_) {
     uint32_t last_read = 0;
     uint8_t data[PRINT_BUFFER_SIZE + 1] = {0};
     while (true) {
diff --git a/kernel/libk/libk.c b/kernel/libk/libk.c
index 7afd4e7..f6263d2 100644
--- a/kernel/libk/libk.c
+++ b/kernel/libk/libk.c
@@ -2,8 +2,9 @@
 // Created by rick on 02-02-21.
 //
 
+#include <attributes.h>
+
 #include <myke/libk/kprint.h>
-#include <myke/attributes.h>
 #include <myke/libk/libk.h>
 
 bool k_addr_in_kspace(void *addr) {
@@ -14,13 +15,13 @@ void k_wait_for_interrupt() {
     __asm__ __volatile__("hlt;");
 }
 
-void noreturn k_panics(const char *msg) {
+void att_noreturn k_panics(const char *msg) {
     // todo this is not printed
     kprint_sync(msg);
     k_panic();
 }
 
-void noreturn k_panic() {
+void att_noreturn k_panic() {
     kprint_sync("PANIC!");
     while (1) {
         __asm__ __volatile__("cli;"
diff --git a/kernel/libk/syscall.c b/kernel/libk/syscall.c
index 8648bc3..dfda4ec 100644
--- a/kernel/libk/syscall.c
+++ b/kernel/libk/syscall.c
@@ -2,10 +2,10 @@
 // Created by rick on 22-02-21.
 //
 
+#include <attributes.h>
 #include <sys/types.h>
 
 #include <myke/libk/syscall.h>
-#include <myke/attributes.h>
 
 void syscall1(uint32_t arg1) {
     __asm__("int $0x80"
@@ -19,7 +19,7 @@ void syscall2(uint32_t arg1, uint32_t arg2) {
     : "a"(arg1), "b"(arg2));
 }
 
-void noreturn syscall_start_scheduler() {
+void att_noreturn syscall_start_scheduler() {
     syscall1(SYSCALL_START_SCHEDULER);
     while (1) { __asm__("hlt"); };
 }
diff --git a/kernel/mem/mem.c b/kernel/mem/mem.c
index 4526681..7a6fcbc 100644
--- a/kernel/mem/mem.c
+++ b/kernel/mem/mem.c
@@ -2,13 +2,13 @@
 // Created by rick on 22-04-20.
 //
 
+#include <attributes.h>
 #include <stdio.h>
 #include <sys/types.h>
 
-#include <myke/mem/pmm.h>
-#include <myke/mem/mem.h>
 #include <myke/libk/libk.h>
-#include <myke/attributes.h>
+#include <myke/mem/mem.h>
+#include <myke/mem/pmm.h>
 
 #define MEMMAP_ENTRIES 16
 
@@ -25,7 +25,7 @@ typedef struct {
     uint32_t address;
     uint32_t length;
     uint32_t type;
-} packed mmap_entry;
+} att_packed mmap_entry;
 
 int last_memmap_entry = 0;
 mmap_entry memmap[MEMMAP_ENTRIES] = {
diff --git a/kernel/mem/paging.c b/kernel/mem/paging.c
index ac9371c..fecd022 100644
--- a/kernel/mem/paging.c
+++ b/kernel/mem/paging.c
@@ -2,11 +2,11 @@
 // Created by rick on 21-02-21.
 //
 
+#include <attributes.h>
 #include <stdbool.h>
 #include <sys/types.h>
 
 #include <myke/mem/paging.h>
-#include <myke/attributes.h>
 
 #define TABLE_ADDR_MASK 0xFFFFF000
 #define DIRECTORY_SIZE 1024
@@ -25,10 +25,10 @@ typedef struct {
             bool page_size: 1;
             bool global: 1; // ignored
             uint8_t avail: 3;
-        } packed;
+        } att_packed;
         uint32_t addr;
     };
-} packed page_directory_entry;
+} att_packed page_directory_entry;
 
 typedef struct {
     union {
@@ -43,12 +43,12 @@ typedef struct {
             char ignored: 1;
             bool global: 1;
             uint8_t available: 3;
-        } packed;
+        } att_packed;
         uint32_t addr;
     };
-} packed page_table_entry;
+} att_packed page_table_entry;
 
-page_directory_entry page_directory[DIRECTORY_SIZE] at_aligned(4096);
+page_directory_entry page_directory[DIRECTORY_SIZE] att_aligned(4096);
 
 void page_pre_init() {
     for (int i = 0; i < DIRECTORY_SIZE; ++i) {
diff --git a/kernel/tasks/task.c b/kernel/tasks/task.c
index 525320a..0f86613 100644
--- a/kernel/tasks/task.c
+++ b/kernel/tasks/task.c
@@ -2,15 +2,15 @@
 // Created by rick on 22-02-21.
 //
 
-#include <stdlib.h>
+#include <attributes.h>
 #include <stdbool.h>
+#include <stdlib.h>
 #include <string.h>
 
-#include <myke/tasks/task.h>
 #include <myke/cpu/cpu.h>
-#include <myke/mem/pmm.h>
-#include <myke/attributes.h>
 #include <myke/libk/libk.h>
+#include <myke/mem/pmm.h>
+#include <myke/tasks/task.h>
 
 #define stack_end(task) ((task)->stack + ((task)->stack_page_count * PAGE_SIZE))
 
@@ -48,7 +48,7 @@ typedef struct {
     task_entrypoint entrypoint;
     void *entry_data;
     char alignment[4];
-} packed task_stack_start;
+} att_packed task_stack_start;
 
 volatile uint32_t task_locked = 0;
 
@@ -62,12 +62,12 @@ uint32_t last_tid = 0;
 extern switch_task(task_registers_t
 **, task_registers_t*);
 
-extern cdecl noreturn void __task_entry_point();
+extern att_cdecl att_noreturn void __task_entry_point();
 
-extern noreturn void __task_entry_point_inner();
+extern att_noreturn void __task_entry_point_inner();
 
 // explicit cdecl calling convention
-void cdecl noreturn task_entry_point(task_entrypoint entrypoint, void *entry_data) {
+void att_cdecl att_noreturn task_entry_point(task_entrypoint entrypoint, void *entry_data) {
     entrypoint(entry_data);
 //    task_end_self();
     while (true); // halt
@@ -114,7 +114,7 @@ void task_suspend() {
     task_switch_next();
 }
 
-void noreturn task_idle(void *data) {
+void att_noreturn task_idle(void *data) {
     while (true) __asm__("hlt");
 }
 
diff --git a/kernel/util/power.c b/kernel/util/power.c
index 79c455d..6b52d34 100644
--- a/kernel/util/power.c
+++ b/kernel/util/power.c
@@ -2,12 +2,13 @@
 // Created by rick on 03-03-21.
 //
 
+#include <attributes.h>
+
 #include <myke/drivers/ports.h>
-#include <myke/attributes.h>
 #include <myke/libk/libk.h>
 #include <myke/util/power.h>
 
-void noreturn power_shutdown() {
+void att_noreturn power_shutdown() {
     port_word_out(PORT_ACPI, PORT_ACPI_SHUTDOWN);
     port_word_out(PORT_QEMU_COMMAND, PORT_QEMU_COMMAND_SHUTDOWN);
     port_word_out(PORT_VBOX, PORT_VBOX_SHUTDOWN);