[kernel] Add automatic verification to syscalls

Since we have a DSL for specifying syscalls, we can create a verificaton
method for each syscall that can cover most argument (and eventually
capability) verification instead of doing it piecemeal in each syscall
implementation, which can be more error-prone.

Now a new _syscall_verify_* function exists for every syscall, which
calls the real implementation. The syscall table for the syscall handler
now maps to these verify functions.

Other changes:

- Updated the definition grammar to allow options to have a "key:value"
  style, to eventually support capabilities.
- Added an "optional" option for parameters that says a syscall will
  accept a null value.
- Some bonnibel fixes, as definition file changes weren't always
  properly causing updates in the build dep graph.
- The syscall implementation function signatures are no longer exposed
  in syscall.h. Also, the unused syscall enum has been removed.

scripts/bonnibel/module.py

@@ -141,6 +141,7 @@ class Module:
 
             inputs = []
             parse_deps = []
+            parse_dep = "${module_dir}/.parse_dep.phony"
 
             for start in self.sources:
                 source = start
@@ -148,6 +149,11 @@ class Module:
                 while source and source.action:
                     output = source.output
 
+                    if source.action.parse_deps:
+                        oodeps = [parse_dep]
+                    else:
+                        oodeps = []
+
                     if source.action.rule:
                         build.newline()
                         build.build(
@@ -156,6 +162,7 @@ class Module:
                             inputs = source.input,
                             implicit = list(map(resolve, source.deps)) +
                                        list(source.action.deps),
+                            order_only = oodeps,
                             variables = {"name": source.name},
                         )
 
@@ -167,7 +174,6 @@ class Module:
 
                     source = output
 
-            parse_dep = "${module_dir}/.parse_dep.phony"
             build.newline()
             build.build(
                 rule = "touch",
@@ -183,7 +189,7 @@ class Module:
                 rule = self.kind,
                 outputs = output,
                 inputs = inputs,
-                implicit = [parse_dep] + libs,
+                implicit = libs,
                 order_only = order_only,
             )
 

scripts/bonnibel/source.py

@@ -3,6 +3,7 @@ class Action:
     implicit = property(lambda self: False)
     rule = property(lambda self: None)
     deps = property(lambda self: tuple())
+    parse_deps = property(lambda self: False)
 
     def __init__(self, name):
         self.__name = name
@@ -14,6 +15,7 @@ class Action:
 class Compile(Action):
     rule = property(lambda self: f'compile_{self.name}')
     deps = property(lambda self: ("${module_dir}/.parse_dep.phony",))
+    parse_deps = property(lambda self: True)
 
     def __init__(self, name, suffix = ".o"):
         super().__init__(name)