diff --git a/Documentation/userspace-api/spec_ctrl.rst b/Documentation/userspace-api/spec_ctrl.rst
index ca89151fc0a8..61fe020b23a2 100644
--- a/Documentation/userspace-api/spec_ctrl.rst
+++ b/Documentation/userspace-api/spec_ctrl.rst
@@ -81,11 +81,15 @@ Value   Meaning
 ERANGE  arg3 is incorrect, i.e. it's neither PR_SPEC_ENABLE nor
         PR_SPEC_DISABLE nor PR_SPEC_FORCE_DISABLE.
 
-ENXIO   Control of the selected speculation misfeature is not possible.
-        See PR_GET_SPECULATION_CTRL.
+ENXIO   For PR_SPEC_STORE_BYPASS: control of the selected speculation misfeature
+        is not possible via prctl, because of the system's boot configuration.
+
+EPERM   Speculation was disabled with PR_SPEC_FORCE_DISABLE and caller tried to
+        enable it again.
+
+EPERM   For PR_SPEC_L1D_FLUSH and PR_SPEC_INDIRECT_BRANCH: control of the
+        mitigation is not possible because of the system's boot configuration.
 
-EPERM   Speculation was disabled with PR_SPEC_FORCE_DISABLE and caller
-        tried to enable it again.
 ======= =================================================================
 
 Speculation misfeature controls