Bunch of code clean up, found many bugs, will patch in next commit.

Author: pradosh-arduino

source/compile_commands.json

@@ -69,6 +69,11 @@
     "file": "/home/pradosh/osdev/source/kernel/C/user-input/ps2-mouse.c",
     "command": "clang -std=gnu11 -ffreestanding -w -fno-common -fno-stack-protector -fno-stack-check -fno-lto -fno-builtin -fno-omit-frame-pointer -Og -g -fPIE -I includes -I src -m64 -march=x86-64 -mno-80387 -mno-mmx -mno-red-zone -mno-sse -mno-sse2 -MMD -MP -c /home/pradosh/osdev/source/kernel/C/user-input/ps2-mouse.c -o /dev/null"
   },
+  {
+    "directory": "/home/pradosh/osdev/source",
+    "file": "/home/pradosh/osdev/source/kernel/C/user-input/tty.c",
+    "command": "clang -std=gnu11 -ffreestanding -w -fno-common -fno-stack-protector -fno-stack-check -fno-lto -fno-builtin -fno-omit-frame-pointer -Og -g -fPIE -I includes -I src -m64 -march=x86-64 -mno-80387 -mno-mmx -mno-red-zone -mno-sse -mno-sse2 -MMD -MP -c /home/pradosh/osdev/source/kernel/C/user-input/tty.c -o /dev/null"
+  },
   {
     "directory": "/home/pradosh/osdev/source",
     "file": "/home/pradosh/osdev/source/kernel/C/logger.c",

source/includes/idt.h

@@ -15,6 +15,17 @@
 
 #include <stdint.h>
 
+#define ICW1_INIT 0x10
+#define ICW1_ICW4 0x01
+#define ICW4_8086 0x01
+
+#define IA32_EFER   0xC0000080
+#define IA32_STAR   0xC0000081
+#define IA32_LSTAR  0xC0000082
+#define IA32_FMASK  0xC0000084
+
+#define EFER_SCE (1 << 0)
+
 typedef struct IDTEntry
 {
         uint16_t offset_1;        // offset bits 0..15
@@ -32,6 +43,18 @@ typedef struct IDTPointer
         uint64_t offset;
 }__attribute__((packed)) IDTPointer;
 
+/**
+ * @brief Located inside /interrupts/syscall-x86_64.asm
+ * 
+ */
+extern void syscall_entry(void);
+
+/**
+ * @brief Tells the CPU to use the syscall instruction.
+ * 
+ */
+void init_syscall();
+
 void initIdt();
 void setIdtEntry(IDTEntry *target, uint64_t offset, uint16_t selector, uint8_t ist, uint8_t type_attributes);
 

source/includes/keyboard.h

@@ -75,12 +75,11 @@ uint8_t getc();
 int getc_nonblock();
 
 /**
- * @brief Non-blocking read directly from the PS/2 controller.
+ * @brief Converts the scancode passed to it to ASCII characters.
  * 
- * @return int Character if available, 0 if no input or only a modifier event
+ * @param data Scancode
+ * @return int eqivalent of a character.
  */
-int kgetc_nonblock();
-
 int handle_char_from_scancode(uint8_t data);
 
 #endif

source/includes/meltdown.h

@@ -12,13 +12,11 @@
 #ifndef MELTDOWN_H
 #define MELTDOWN_H
 
-#include <stddef.h>
-#include <stdint.h>
 #include <basics.h>
-#include <kernel.h>
-#include <opengl/glbackend.h>
 #include <graphics.h>
 
+extern struct InterruptFrame;
+
 /**
  * @brief The Meltdown (Panic) Screen
  * 
@@ -29,6 +27,6 @@
  * @param cr2
  * @param int_no
  */
-void meltdown_screen(cstring message, cstring file, int line, int64 error_code, int64 cr2, int64 int_no, InterruptFrame* frame);
+void meltdown_screen(cstring message, cstring file, int line, int64 error_code, int64 cr2, int64 int_no, struct InterruptFrame* frame);
 
 #endif

source/includes/syscalls.h

@@ -16,58 +16,58 @@
 
 #define PRAD_MAGIC 0xBADF00D
 
-#define LINUX_SYS_READ        0
-#define LINUX_SYS_WRITE       1
-#define LINUX_SYS_OPEN        2
-#define LINUX_SYS_CLOSE       3
-#define LINUX_SYS_STAT        4
-#define LINUX_SYS_FSTAT       5
-#define LINUX_SYS_LSEEK       8
-#define LINUX_SYS_MPROTECT    10
-#define LINUX_SYS_MMAP        9
-#define LINUX_SYS_MUNMAP      11
-#define LINUX_SYS_BRK         12
-#define LINUX_SYS_RT_SIGACTION 13
-#define LINUX_SYS_RT_SIGPROCMASK 14
-#define LINUX_SYS_IOCTL       16
-#define LINUX_SYS_ACCESS      21
-#define LINUX_SYS_WRITEV      20
-#define LINUX_SYS_DUP         32
-#define LINUX_SYS_DUP2        33
-#define LINUX_SYS_NANOSLEEP   35
-#define LINUX_SYS_GETPID      39
-#define LINUX_SYS_EXECVE      59
-#define LINUX_SYS_EXIT        60
-#define LINUX_SYS_CHDIR       80
-#define LINUX_SYS_UNAME       63
-#define LINUX_SYS_FCNTL       72
-#define LINUX_SYS_GETCWD      79
-#define LINUX_SYS_READLINK    89
-#define LINUX_SYS_UMASK       95
-#define LINUX_SYS_GETUID      102
-#define LINUX_SYS_GETEUID     107
-#define LINUX_SYS_GETGID      104
-#define LINUX_SYS_GETEGID     108
-#define LINUX_SYS_GETPPID     110
-#define LINUX_SYS_SIGALTSTACK 131
-#define LINUX_SYS_ARCH_PRCTL  158
-#define LINUX_SYS_GETTID      186
-#define LINUX_SYS_GETDENTS64  217
-#define LINUX_SYS_SET_TID_ADDRESS 218
-#define LINUX_SYS_CLOCK_GETTIME 228
-#define LINUX_SYS_OPENAT      257
-#define LINUX_SYS_NEWFSTATAT  262
-#define LINUX_SYS_READLINKAT  267
-#define LINUX_SYS_FACCESSAT   269
-#define LINUX_SYS_SET_ROBUST_LIST 273
-#define LINUX_SYS_PRLIMIT64   302
-#define LINUX_SYS_GETRANDOM   318
-#define LINUX_SYS_STATX       332
-#define LINUX_SYS_EXIT_GROUP  231
-#define LINUX_SYS_TGKILL      234
+#define LINUX_SYS_READ              0
+#define LINUX_SYS_WRITE             1
+#define LINUX_SYS_OPEN              2
+#define LINUX_SYS_CLOSE             3
+#define LINUX_SYS_STAT              4
+#define LINUX_SYS_FSTAT             5
+#define LINUX_SYS_LSEEK             8
+#define LINUX_SYS_MMAP              9
+#define LINUX_SYS_MPROTECT          10
+#define LINUX_SYS_MUNMAP            11
+#define LINUX_SYS_BRK               12
+#define LINUX_SYS_RT_SIGACTION      13
+#define LINUX_SYS_RT_SIGPROCMASK    14
+#define LINUX_SYS_IOCTL             16
+#define LINUX_SYS_ACCESS            21
+#define LINUX_SYS_WRITEV            20
+#define LINUX_SYS_DUP               32
+#define LINUX_SYS_DUP2              33
+#define LINUX_SYS_NANOSLEEP         35
+#define LINUX_SYS_GETPID            39
+#define LINUX_SYS_EXECVE            59
+#define LINUX_SYS_EXIT              60
+#define LINUX_SYS_CHDIR             80
+#define LINUX_SYS_UNAME             63
+#define LINUX_SYS_FCNTL             72
+#define LINUX_SYS_GETCWD            79
+#define LINUX_SYS_READLINK          89
+#define LINUX_SYS_UMASK             95
+#define LINUX_SYS_GETUID            102
+#define LINUX_SYS_GETEUID           107
+#define LINUX_SYS_GETGID            104
+#define LINUX_SYS_GETEGID           108
+#define LINUX_SYS_GETPPID           110
+#define LINUX_SYS_SIGALTSTACK       131
+#define LINUX_SYS_ARCH_PRCTL        158
+#define LINUX_SYS_GETTID            186
+#define LINUX_SYS_FUTEX             202
+#define LINUX_SYS_GETDENTS64        217
+#define LINUX_SYS_SET_TID_ADDRESS   218
+#define LINUX_SYS_CLOCK_GETTIME     228
+#define LINUX_SYS_OPENAT            257
+#define LINUX_SYS_NEWFSTATAT        262
+#define LINUX_SYS_READLINKAT        267
+#define LINUX_SYS_FACCESSAT         269
+#define LINUX_SYS_SET_ROBUST_LIST   273
+#define LINUX_SYS_PRLIMIT64         302
+#define LINUX_SYS_GETRANDOM         318
+#define LINUX_SYS_STATX             332
+#define LINUX_SYS_EXIT_GROUP        231
+#define LINUX_SYS_TGKILL            234
 
 #define LINUX_EAGAIN 11
-#define LINUX_SYS_FUTEX 202  // confirm your syscall number
 
 typedef struct syscall_frame {
     uint64_t r9;
@@ -86,19 +86,36 @@ typedef struct syscall_frame {
 } syscall_frame_t;
 
 /**
- * @brief Prefix for the syscalls
+ * @brief Prefix for linux-compatible syscall traces.
  */
-#define syscalls_prefix "Syscall Invoked: "
+#define linux_syscalls_prefix "Linux syscall: "
 
 /**
- * @brief Prefix for linux-compatible syscall traces.
+ * @brief Wrapper for the dispatcher which gets called for interrupt number 0x80
+ * 
+ * @param frame 
  */
-#define linux_syscalls_prefix "Linux syscall: "
+void int80_handler(InterruptFrame* frame);
 
-void invoke_syscall(int64 num);
-void syscalls_handler(InterruptFrame* frame);
-void syscall_handler_syscall(syscall_frame_t* f);
+/**
+ * @brief Wrapper for the dispatcher which gets called for running the syscall instruction
+ * 
+ * @param f 
+ */
+void syscall_handler(syscall_frame_t* f);
 
+/**
+ * @brief Dispatches syscall based on the syscall number.
+ * 
+ * @param nr 
+ * @param arg1 
+ * @param arg2 
+ * @param arg3 
+ * @param arg4 
+ * @param arg5 
+ * @param arg6 
+ * @return uint64_t 
+ */
 uint64_t syscall_dispatch (
     uint64_t nr,
     uint64_t arg1,

source/includes/tss.h

@@ -55,6 +55,12 @@ extern struct tss_entry tss;
  */
 extern uint8_t kernel_stack[0x4000];
 
+/**
+ * @brief The starting address of kernel's stack.
+ * 
+ */
+extern uint64_t kernel_stack_top;
+
 /**
  * @brief Initialize TSS.
  * 

source/includes/userland.h

@@ -26,6 +26,74 @@
 #define USER_PHDR_VADDR  (USER_TLS_VADDR + USER_TLS_REGION_SIZE)
 #define USER_STACK_TOP   0x00007FFFFFFFF000ULL // near top of canonical lower half
 
+#define LINUX_AT_NULL    0
+#define LINUX_AT_PHDR    3
+#define LINUX_AT_PHENT   4
+#define LINUX_AT_PHNUM   5
+#define LINUX_AT_PAGESZ  6
+#define LINUX_AT_BASE    7
+#define LINUX_AT_FLAGS   8
+#define LINUX_AT_ENTRY   9
+#define LINUX_AT_UID     11
+#define LINUX_AT_EUID    12
+#define LINUX_AT_GID     13
+#define LINUX_AT_EGID    14
+#define LINUX_AT_PLATFORM 15
+#define LINUX_AT_HWCAP   16
+#define LINUX_AT_HWCAP2  26
+#define LINUX_AT_CLKTCK  17
+#define LINUX_AT_SECURE  23
+#define LINUX_AT_RANDOM  25
+#define LINUX_AT_EXECFN  31
+#define IA32_FS_BASE_MSR 0xC0000100
+#define USER_AUXV_MAX    18
+
+typedef struct {
+    int i[4];
+} glibc_128bits_t;
+
+typedef union {
+    uint64_t counter;
+    struct {
+        void* val;
+        void* to_free;
+    } pointer;
+} glibc_dtv_t;
+
+typedef struct {
+    uint64_t tcb;
+    glibc_dtv_t* dtv;
+    uint64_t self;
+    uint32_t multiple_threads;
+    uint32_t gscope_flag;
+    uint64_t sysinfo;
+    uint64_t stack_guard;
+    uint64_t pointer_guard;
+    uint64_t unused_vgetcpu_cache[2];
+    uint32_t feature_1;
+    int32_t __glibc_unused1;
+    void* __private_tm[4];
+    void* __private_ss;
+    uint64_t ssp_base;
+    glibc_128bits_t __glibc_unused2[8][4] __attribute__((aligned(32)));
+    void* __padding[8];
+} glibc_tcb_head_t;
+
+typedef struct {
+    glibc_tcb_head_t head;
+    glibc_dtv_t dtv[2];
+} glibc_tls_block_t;
+
+_Static_assert(__builtin_offsetof(glibc_tcb_head_t, stack_guard) == 0x28, "glibc stack_guard offset mismatch");
+_Static_assert(__builtin_offsetof(glibc_tcb_head_t, pointer_guard) == 0x30, "glibc pointer_guard offset mismatch");
+_Static_assert(__builtin_offsetof(glibc_tcb_head_t, __private_ss) == 0x70, "glibc __private_ss offset mismatch");
+_Static_assert(__builtin_offsetof(glibc_tcb_head_t, __glibc_unused2) == 0x80, "glibc __glibc_unused2 offset mismatch");
+
+typedef struct {
+    uint64_t key;
+    uint64_t value;
+} auxv_pair_t;
+
 void enter_userland_at(uint64_t entry_point);
 int userland_exec(const char* path, int argc, const char* const* argv, const char* const* envp);
 void userland_heap_init(void);

source/kernel/C/cc-asm.c

@@ -81,12 +81,31 @@ void set_interrupts() {
 
 
 /**
- * @brief It uses while loops instead of assembly's halt,
- * Good for Userland
+ * @brief It uses while loops instead of assembly's halt.
  * 
  */
 void high_level_halt(){
     while(1){
-        // TODO!
+        asm volatile ("pause");
     }
+}
+
+void wrmsr64(uint32_t msr, uint64_t value) {
+    uint32_t low = (uint32_t)value;
+    uint32_t high = (uint32_t)(value >> 32);
+    asm volatile("wrmsr" : : "c"(msr), "a"(low), "d"(high));
+}
+
+uint64_t rdmsr64(uint32_t msr) {
+    uint32_t low = 0;
+    uint32_t high = 0;
+    asm volatile("rdmsr" : "=a"(low), "=d"(high) : "c"(msr));
+    return ((uint64_t)high << 32) | low;
+}
+
+uint64_t rdtsc64(void) {
+    uint32_t low = 0;
+    uint32_t high = 0;
+    asm volatile("rdtsc" : "=a"(low), "=d"(high));
+    return ((uint64_t)high << 32) | low;
 }