Reimplement the terminal user access via separate syscalls

kernel/syscall/syscall.c

@@ -11,6 +11,7 @@
 #include "syscall/dev.h"
 #include "syscall/time.h"
 #include "syscall/ipcmbus.h"
+#include "syscall/term.h"
 #include "errors.h"
 #include "kprintf.h"
 
@@ -75,4 +76,6 @@ SyscallFn SYSCALL_TABLE[SYSCALLS_MAX] = {
   [SYS_IPC_MBUSCONSUME] = &sys_ipc_mbusconsume,
   [SYS_IPC_MBUSATTCH]   = &sys_ipc_mbusattch,
   [SYS_IPC_MBUSDTTCH]   = &sys_ipc_mbusdttch,
+
+  [SYS_TERM_WRITE]    = &sys_term_write,
 };

kernel/syscall/term.c

@@ -0,0 +1,18 @@
+#include <stdint.h>
+#include <stddef.h>
+#include "syscall/syscall.h"
+#include "kprintf.h"
+#include "errors.h"
+
+int32_t SYSCALL2(sys_term_write, buffer1, len1) {
+  const char *buffer = (const char *)buffer1;
+  size_t len = len1;
+
+  if (buffer == NULL) {
+    return E_INVALIDARGUMENT;
+  }
+
+  kprintf("%.*s", (int)len, buffer);
+
+  return E_OK;
+}

kernel/syscall/term.h

@@ -0,0 +1,10 @@
+#ifndef SYSCALL_TERM_H_
+#define SYSCALL_TERM_H_
+
+#include <stdint.h>
+#include <stddef.h>
+#include "syscall/syscall.h"
+
+int32_t SYSCALL2(sys_term_write, buffer1, len1);
+
+#endif // SYSCALL_TERM_H_