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diff --git a/openpower/sv/ldst.mdwn b/openpower/sv/ldst.mdwn
index 16615872e8f8c83ff7049fe806ea3e4362b4f8de..baacec2d5804d98c627410bd894b6fa6332a36e5 100644 (file)
--- a/openpower/sv/ldst.mdwn
+++ b/openpower/sv/ldst.mdwn
@@ -215,6 +215,10 @@ Note that cache-inhibited LD/ST (`ldcix`) when VSPLAT is activated will perform
 If a genuine cache-inhibited LD-VSPLAT is required then a *scalar*
 cache-inhibited LD should be performed, followed by a VSPLAT-augmented mv.
 
+## LD/ST ffirst
+
+ffirst LD/ST to multiple pages via a Vectorised base is considered a security risk due to the abuse of probing multiple pages in rapid succession and getting feedback on which pages would fail.  Therefore in these special circumstances requesting ffirst with a vector base is instead interpreted as element-strided LD/ST.  See <https://bugs.libre-soc.org/show_bug.cgi?id=561>
+
 # LOAD/STORE Elwidths <a name="ldst"></a>
 
 Loads and Stores are almost unique in that the OpenPOWER Scalar ISA