Added <errno.h> and made kernel use it

kernel/include/errno.h

@@ -0,0 +1,35 @@
+#ifndef _ERRNO_H
+#define _ERRNO_H
+
+#include <kernel.h>
+
+#define ERRNO_MAX 4095
+
+#define IS_ERR(_ptr) ((uintptr_t)(_ptr) >= (uintptr_t)(-ERRNO_MAX))
+
+#define ERR_PTR(_err) ((void*)(_err))
+#define PTR_ERR(_ptr) ((int)(intptr_t)(_ptr))
+
+// TODO: Add correct errno.h numbers
+enum {
+	SUCCESS = 0,
+	ENOMEM,		// Cannot allocate memory
+	EPERM,		// Operation not permitted
+	ENOENT,		// No entry (no such file or directory)
+	EIO,		// Input/Output error
+	ENXIO,		// No such device or address
+	EAGAIN,		// Resource temporarly busy
+	EACCES,		// Permission denied
+	EFAULT,		// Bad address
+	ENODEV,		// No such device
+	EINVAL,		// Invalid argument
+	EDOM,		// Numerical argument out of domain
+	ERANGE,		// Numerical result out of range
+	ENOSYS,		// Function not implemented
+	ENOTSUP,	// Not supported
+	EILLSEQ,	// Illegal byte sequence
+	EOVERFLOW,	// 
+	EALIGN,		// Not aligned
+};
+
+#endif

kernel/include/idt.h

@@ -32,6 +32,6 @@ struct idt_pointer {
 } __packed;
 
 int idt_init(void);
-void idt_set_gate(uint8_t i, void* handler, uint8_t flags);
+void idt_set_gate(uint8_t i, void* handler, uint8_t flags, uint8_t ist);
 
 #endif

kernel/include/paging.h

@@ -41,11 +41,11 @@ static inline bool pag_is_user_addr(void* vaddr) { return (uintptr_t)vaddr < 0x0
 // NOTE: All uint64_t* are VIRTUAL addresses
 int	  pag_init(void);
 uint64_t* pag_get_pte(uint64_t* pml4, void* vaddr);
-void	  pag_map(uint64_t* pml4, void* vaddr, void* paddr, uint64_t flags);
-void	  pag_map_region(uint64_t* pml4, void* vaddr, void* paddr, size_t count, uint64_t flags);
-void	  pag_unmap(uint64_t* pml4, void* vaddr);
-void	  pag_unmap_region(uint64_t* pml4, void* vaddr, size_t count);
-void	  pag_protect(uint64_t* pml4, void* vaddr, uint64_t flags);
+int	  pag_map(uint64_t* pml4, void* vaddr, void* paddr, uint64_t flags);
+int	  pag_map_region(uint64_t* pml4, void* vaddr, void* paddr, size_t count, uint64_t flags);
+int	  pag_unmap(uint64_t* pml4, void* vaddr);
+int	  pag_unmap_region(uint64_t* pml4, void* vaddr, size_t count);
+int	  pag_protect(uint64_t* pml4, void* vaddr, uint64_t flags);
 void*	  pag_get_phys(uint64_t* pml4, void* vaddr);
 void	  pag_set_pml4(uint64_t* pml4);
 uint64_t* pag_get_pml4(void);

kernel/include/pmm.h

@@ -5,6 +5,6 @@
 
 int pmm_init(void);
 void* pmm_alloc(void);
-void pmm_free(void*);
+int pmm_free(void*);
 
 #endif

kernel/include/serial.h

@@ -18,6 +18,7 @@ int  serial_rcvd(int dev);
 char serial_recv(int dev);
 void serial_write(int dev, char* buf, size_t len);
 void serial_puts(int dev, char* s);
+void serial_cls(int dev);
 
 int debugf(char* fmt, ...);
 int vdebugf(char* fmt, va_list args);