1 files changed, 75 insertions, 0 deletions
diff --git a/sys/tools/gdb/freebsd.py b/sys/tools/gdb/freebsd.py
new file mode 100644
index 000000000000..81ea60373348
--- /dev/null
+++ b/sys/tools/gdb/freebsd.py
@@ -0,0 +1,75 @@
+#
+# Copyright (c) 2025 Mark Johnston <markj@FreeBSD.org>
+#
+# SPDX-License-Identifier: BSD-2-Clause
+#
+
+import gdb
+
+def symval(name):
+    sym = gdb.lookup_global_symbol(name)
+    if sym is None:
+        sym = gdb.lookup_static_symbol(name)
+        if sym is None:
+            raise gdb.GdbError(f"Symbol '{name}' not found")
+    return sym.value()
+
+
+def _queue_foreach(head, field, headf, nextf):
+    elm = head[headf]
+    while elm != 0:
+        yield elm
+        elm = elm[field][nextf]
+
+
+def list_foreach(head, field):
+    """sys/queue.h-style iterator."""
+    return _queue_foreach(head, field, "lh_first", "le_next")
+
+
+def tailq_foreach(head, field):
+    """sys/queue.h-style iterator."""
+    return _queue_foreach(head, field, "tqh_first", "tqe_next")
+
+
+def linker_file_foreach():
+    """Iterate over loaded linker files."""
+    return tailq_foreach(symval("linker_files"), "link")
+
+
+def pcpu_foreach():
+    mp_maxid = symval("mp_maxid")
+    cpuid_to_pcpu = symval("cpuid_to_pcpu")
+
+    cpu = 0
+    while cpu <= mp_maxid:
+        pcpu = cpuid_to_pcpu[cpu]
+        if pcpu:
+            yield pcpu
+        cpu = cpu + 1
+
+
+def tid_to_gdb_thread(tid):
+    """Convert a FreeBSD kernel thread ID to a gdb inferior thread."""
+    for thread in gdb.inferiors()[0].threads():
+        if thread.ptid[2] == tid:
+            return thread
+    else:
+        return None
+
+
+def tdfind(tid, pid=-1):
+    """Convert a FreeBSD kernel thread ID to a struct thread pointer."""
+    td = tdfind.cached_threads.get(int(tid))
+    if td:
+        return td
+
+    for p in list_foreach(symval("allproc"), "p_list"):
+        if pid != -1 and pid != p['p_pid']:
+            continue
+        for td in tailq_foreach(p['p_threads'], "td_plist"):
+            ntid = td['td_tid']
+            tdfind.cached_threads[int(ntid)] = td
+            if ntid == tid:
+                return td
+tdfind.cached_threads = dict()