From 3a12d033aa7613cda7913b4ef38d02db125619ad Mon Sep 17 00:00:00 2001
From: Michael Hendricks <michael@ndrix.org>
Date: Thu, 18 Jan 2024 06:36:09 -0700
Subject: [PATCH] Disable control flow integrity on OpenBSD

Fixes #12903
---
 Changes      |  4 ++++
 configure    | 11 +++++++++++
 configure.ac |  8 ++++++++
 3 files changed, 23 insertions(+)

diff --git a/Changes b/Changes
index 0d15b8bb80cb..8ddd60792339 100644
--- a/Changes
+++ b/Changes
@@ -2314,6 +2314,10 @@ OCaml 4.14 maintenance version
   (Xavier Leroy and Anil Madhavapeddy, review by Anil Madhavapeddy and
   Sébastien Hinderer)
 
+- #12903: Disable control flow integrity on OpenBSD >= 7.4 to avoid
+  illegal instruction errors on certain CPUs.
+  (Michael Hendricks, review by Miod Vallat)
+
 ### Bug fixes:
 
 - #12878: fix incorrect treatment of injectivity for private recursive types.
diff --git a/configure b/configure
index fde1f82e28b9..21abebf78caf 100755
--- a/configure
+++ b/configure
@@ -15429,6 +15429,17 @@ case $host in #(
      ;;
 esac
 
+# Disable control flow integrity
+
+case $host in #(
+  *-*-openbsd7.[4-9]|*-*-openbsd[89].*) :
+    oc_ldflags="$oc_ldflags -Wl,-z,nobtcfi"
+     natdynlinkopts="$natdynlinkopts -Wl,-z,nobtcfi" ;; #(
+  *) :
+     ;;
+esac
+
+
 # Configure native dynlink
 
 natdynlink=false
diff --git a/configure.ac b/configure.ac
index 92037cc85697..3bde30ecca7e 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1211,6 +1211,14 @@ AS_CASE([$host],
     [oc_ldflags="$oc_ldflags -Wl,--no-execute-only"
      natdynlinkopts="$natdynlinkopts -Wl,--no-execute-only"])
 
+# Disable control flow integrity
+
+AS_CASE([$host],
+  [[*-*-openbsd7.[4-9]|*-*-openbsd[89].*]],
+    [oc_ldflags="$oc_ldflags -Wl,-z,nobtcfi"
+     natdynlinkopts="$natdynlinkopts -Wl,-z,nobtcfi"])
+
+
 # Configure native dynlink
 
 natdynlink=false