[CHERI CSA] Enable CSA for BuildCheriBSD project

pycheribuild/projects/cross/cheribsd.py

@@ -1005,8 +1005,8 @@ def _setup_cross_toolchain_config(self) -> None:
         if not xccinfo.is_clang:
             self.ask_for_confirmation("Cross compiler is not clang, are you sure you want to continue?")
         self.cross_toolchain_config.set_env(
-            XCC=self.CC,
-            XCXX=self.CXX,
+            XCC=self.cc_wrapper,
+            XCXX=self.cxx_wrapper,
             XCPP=self.CPP,
             X_COMPILER_TYPE=xccinfo.compiler,  # This is needed otherwise the build assumes it should build with $CC
         )
@@ -1196,9 +1196,14 @@ def _buildkernel(
             # Don't build a compiler if we are using and external toolchain (only build config, etc)
             if not self.use_bootstrapped_toolchain:
                 kernel_toolchain_opts.set_with_options(LLD_BOOTSTRAP=False, CLANG=False, CLANG_BOOTSTRAP=False)
+            kernel_toolchain_opts.exclude_from_csa = True
             self.run_make("kernel-toolchain", options=kernel_toolchain_opts)
             self.kernel_toolchain_exists = True
         self.info("Building kernels for configs:", " ".join(kernconfs))
+
+        if self.use_csa:
+            kernel_make_args.set(BUILD_WITH_STRICT_TMPPATH=False)  # Look for perl in PATH
+
         self.run_make(
             "buildkernel",
             options=kernel_make_args,
@@ -1523,6 +1528,10 @@ def add_cross_build_options(self) -> None:
         # links from /usr/bin/mail to /usr/bin/Mail won't work on case-insensitve fs
         self.make_args.set_with_options(MAIL=False)
 
+        if self.use_csa:
+            ccinfo = self.get_compiler_info(self.host_CC)
+            self.make_args.set_env(COMPILER_TYPE=ccinfo.compiler)
+
     def libcompat_name(self) -> str:
         if self.crosscompile_target.is_cheri_purecap():
             return "lib64"
@@ -1917,6 +1926,10 @@ def setup_config_options(cls, kernel_only_target=False, install_directory_help=N
             "build the libraries and skip all binaries",
         )
 
+    @classmethod
+    def can_build_with_csa(cls) -> bool:
+        return True
+
     def __init__(self, *args, **kwargs) -> None:
         super().__init__(*args, **kwargs)
         self.extra_kernels_with_mfs: "list[str]" = []

tests/test_argument_parsing.py

@@ -1280,6 +1280,7 @@ def test_mfs_root_kernel_config_options():
         "mfs_root_image",
         "skip_update",
         "use_ccache",
+        "use_csa",
         "use_lto",
         "with_clean",
         "with_debug_files",