feat: add support for aarch64 timer/interrupts, port MontaukOS userspace

toolchain/files/aarch64-montauk.h

@@ -0,0 +1,43 @@
+/*
+    * aarch64-montauk.h
+    * GCC target definitions for aarch64-montauk userspace
+    * (installed as gcc/config/aarch64/montauk.h)
+    * Copyright (c) 2026 Daniel Hammer
+    *
+    * Programs are static, non-PIE ET_EXEC images loaded by the kernel
+    * ELF loader (kernel/src/Sched/ElfLoader.cpp) at their linked
+    * address. The loader maps 4 KiB pages, so segments must not use
+    * the 64 KiB AArch64 default alignment.
+*/
+
+#undef TARGET_OS_CPP_BUILTINS
+#define TARGET_OS_CPP_BUILTINS()            \
+    do {                                    \
+        builtin_define("__montauk__");      \
+        builtin_define("__MONTAUK__");      \
+        builtin_assert("system=montauk");   \
+    } while (0)
+
+/* Inline LL/SC atomics: outline atomics pick LSE at run time from HWCAP,
+   which Montauk does not provide, and their helpers live in libgcc, which
+   -nostdlib programs never link.
+   Signed plain char, as on x86_64-montauk: the userspace is shared between
+   the architectures and its CP1252 text handling assumes it.
+   -moutline-atomics / -funsigned-char still override. */
+#undef CC1_SPEC
+#define CC1_SPEC "%{!moutline-atomics:-mno-outline-atomics} %{!funsigned-char:-fsigned-char}"
+
+#undef LINK_SPEC
+#define LINK_SPEC \
+    "-maarch64elf -X -z max-page-size=0x1000 %{shared:-shared} %{!shared:-static}"
+
+/* As on x86_64-montauk: crt1/crti/crtn from the Montauk libc,
+   crtbegin/crtend from libgcc. */
+#undef STARTFILE_SPEC
+#define STARTFILE_SPEC "crt1.o%s crti.o%s crtbegin.o%s"
+
+#undef ENDFILE_SPEC
+#define ENDFILE_SPEC "crtend.o%s crtn.o%s"
+
+#undef LIB_SPEC
+#define LIB_SPEC "-lc"