feat: add process termination codes and SYS_ABORT; whole-process abort() from any thread in libc and montauk-rt

kernel/src/Common/TerminationCodes.hpp

@@ -0,0 +1,37 @@
+/*
+    * TerminationCodes.hpp
+    * MontaukOS process termination codes.
+    * Copyright (c) 2026 Daniel Hammer
+*/
+
+#pragma once
+
+#include <cstdint>
+
+// Exit code recorded when the kernel ends a process, as opposed to the
+// process calling SYS_EXIT (which is masked to 0..255). Encoded as
+// 256 + POSIX signal number so libc waitpid can report WTERMSIG.
+// Mirrored in userspace at programs/include/montauk/statuscodes.h.
+enum TerminationCodes {
+    TerminationBase = 256,
+    TerminatedIllegalInstruction = TerminationBase + 4,     // SIGILL
+    TerminatedBreakpoint = TerminationBase + 5,             // SIGTRAP
+    TerminatedAborted = TerminationBase + 6,                // SIGABRT
+    TerminatedArithmeticError = TerminationBase + 8,        // SIGFPE
+    TerminatedKilled = TerminationBase + 9,                 // SIGKILL
+    TerminatedAccessViolation = TerminationBase + 11        // SIGSEGV
+};
+
+// Termination code for a user-mode CPU exception. The exact vector is
+// kept in the crash report; this is only the category.
+inline TerminationCodes TerminationFromVector(uint8_t vector) {
+    switch (vector) {
+        case 0x06: return TerminatedIllegalInstruction;     // #UD
+        case 0x01:                                          // #DB
+        case 0x03: return TerminatedBreakpoint;             // #BP
+        case 0x00:                                          // #DE
+        case 0x10:                                          // #MF
+        case 0x13: return TerminatedArithmeticError;        // #XM
+        default:   return TerminatedAccessViolation;        // #PF, #GP, #SS, #NP, #AC, #OF, #BR, #CP, ...
+    }
+}