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-rw-r--r--Documentation/userspace-api/spec_ctrl.rst27
1 files changed, 15 insertions, 12 deletions
diff --git a/Documentation/userspace-api/spec_ctrl.rst b/Documentation/userspace-api/spec_ctrl.rst
index c4dbe6f7cdae..1129c7550a48 100644
--- a/Documentation/userspace-api/spec_ctrl.rst
+++ b/Documentation/userspace-api/spec_ctrl.rst
@@ -28,18 +28,20 @@ PR_GET_SPECULATION_CTRL returns the state of the speculation misfeature
which is selected with arg2 of prctl(2). The return value uses bits 0-3 with
the following meaning:
-==== ===================== ===================================================
-Bit Define Description
-==== ===================== ===================================================
-0 PR_SPEC_PRCTL Mitigation can be controlled per task by
- PR_SET_SPECULATION_CTRL.
-1 PR_SPEC_ENABLE The speculation feature is enabled, mitigation is
- disabled.
-2 PR_SPEC_DISABLE The speculation feature is disabled, mitigation is
- enabled.
-3 PR_SPEC_FORCE_DISABLE Same as PR_SPEC_DISABLE, but cannot be undone. A
- subsequent prctl(..., PR_SPEC_ENABLE) will fail.
-==== ===================== ===================================================
+==== ====================== ==================================================
+Bit Define Description
+==== ====================== ==================================================
+0 PR_SPEC_PRCTL Mitigation can be controlled per task by
+ PR_SET_SPECULATION_CTRL.
+1 PR_SPEC_ENABLE The speculation feature is enabled, mitigation is
+ disabled.
+2 PR_SPEC_DISABLE The speculation feature is disabled, mitigation is
+ enabled.
+3 PR_SPEC_FORCE_DISABLE Same as PR_SPEC_DISABLE, but cannot be undone. A
+ subsequent prctl(..., PR_SPEC_ENABLE) will fail.
+4 PR_SPEC_DISABLE_NOEXEC Same as PR_SPEC_DISABLE, but the state will be
+ cleared on :manpage:`execve(2)`.
+==== ====================== ==================================================
If all bits are 0 the CPU is not affected by the speculation misfeature.
@@ -92,6 +94,7 @@ Speculation misfeature controls
* prctl(PR_SET_SPECULATION_CTRL, PR_SPEC_STORE_BYPASS, PR_SPEC_ENABLE, 0, 0);
* prctl(PR_SET_SPECULATION_CTRL, PR_SPEC_STORE_BYPASS, PR_SPEC_DISABLE, 0, 0);
* prctl(PR_SET_SPECULATION_CTRL, PR_SPEC_STORE_BYPASS, PR_SPEC_FORCE_DISABLE, 0, 0);
+ * prctl(PR_SET_SPECULATION_CTRL, PR_SPEC_STORE_BYPASS, PR_SPEC_DISABLE_NOEXEC, 0, 0);
- PR_SPEC_INDIR_BRANCH: Indirect Branch Speculation in User Processes
(Mitigate Spectre V2 style attacks against user processes)