kernel: print syscall

kernel-src/arch/x86-64/syscall.asm

@@ -1,7 +1,9 @@
 section .rodata
+extern syscall_print
 syscalltab:
+dq syscall_print
 
-syscallcount equ 0
+syscallcount equ 1
 section .text
 global arch_syscall_entry
 ; on entry:

kernel-src/include/kernel/syscalls.h

@@ -2,6 +2,7 @@
 #define _SYSCALLS_H
 
 #include <stdint.h>
+#include <arch/context.h>
 
 typedef struct {
 	uint64_t ret;

kernel-src/sys/syscalls/print.c

@@ -0,0 +1,11 @@
+#include <kernel/syscalls.h>
+#include <printf.h>
+
+syscallret_t syscall_print(context_t *context, char *message) {
+	syscallret_t ret = {
+		.ret = 0,
+		.errno = 0
+	};
+	printf("%s\n", message);
+	return ret;
+}