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-rw-r--r--Documentation/admin-guide/kernel-parameters.txt25
1 files changed, 25 insertions, 0 deletions
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 2522b11e593f..f2d26cb7e853 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -5197,6 +5197,30 @@
retain_initrd [RAM] Keep initrd memory after extraction
+ retbleed= [X86] Control mitigation of RETBleed (Arbitrary
+ Speculative Code Execution with Return Instructions)
+ vulnerability.
+
+ off - no mitigation
+ auto - automatically select a migitation
+ auto,nosmt - automatically select a mitigation,
+ disabling SMT if necessary for
+ the full mitigation (only on Zen1
+ and older without STIBP).
+ ibpb - mitigate short speculation windows on
+ basic block boundaries too. Safe, highest
+ perf impact.
+ unret - force enable untrained return thunks,
+ only effective on AMD f15h-f17h
+ based systems.
+ unret,nosmt - like unret, will disable SMT when STIBP
+ is not available.
+
+ Selecting 'auto' will choose a mitigation method at run
+ time according to the CPU.
+
+ Not specifying this option is equivalent to retbleed=auto.
+
rfkill.default_state=
0 "airplane mode". All wifi, bluetooth, wimax, gps, fm,
etc. communication is blocked by default.
@@ -5568,6 +5592,7 @@
eibrs - enhanced IBRS
eibrs,retpoline - enhanced IBRS + Retpolines
eibrs,lfence - enhanced IBRS + LFENCE
+ ibrs - use IBRS to protect kernel
Not specifying this option is equivalent to
spectre_v2=auto.