--- v8/src/base/platform/platform-openbsd.cc.orig	2026-08-24 20:59:34 UTC
+++ v8/src/base/platform/platform-openbsd.cc
@@ -8,6 +8,7 @@
 #include <errno.h>
 #include <fcntl.h>  // open
 #include <pthread.h>
+#include <pthread_np.h>
 #include <semaphore.h>
 #include <signal.h>
 #include <stdarg.h>
@@ -121,6 +122,17 @@ void OS::AdjustSchedulingParams() {}
 }
 
 void OS::AdjustSchedulingParams() {}
+
+// static
+Stack::StackSlot Stack::ObtainCurrentThreadStackStart() {
+  stack_t ss;
+  void *base;
+  if (pthread_stackseg_np(pthread_self(), &ss) != 0)
+    return nullptr;
+
+  base = (void*)((size_t) ss.ss_sp - ss.ss_size);
+  return reinterpret_cast<uint8_t*>(base) + ss.ss_size;
+}
 
 std::optional<OS::MemoryRange> OS::GetFirstFreeMemoryRangeWithin(
     OS::Address boundary_start, OS::Address boundary_end, size_t minimum_size,