+ /*
+ * FIXME: This code is not architecturally compliant: we modify
+ * the mappings in-place, indeed while they are in use by this
+ * very same code. This may lead to unpredictable behaviour of
+ * the CPU.
+ *
+ * Even modifying the mappings in a separate page table does
+ * not resolve this.
+ *
+ * The architecture strongly recommends that when a mapping is
+ * changed, that it is changed by first going via an invalid
+ * mapping and back to the new mapping. This is to ensure that
+ * no TLB conflicts (caused by the TLB having more than one TLB
+ * entry match a translation) can occur. However, doing that
+ * here will result in unmapping the code we are running.
+ */
+ pr_warn("WARNING: unsafe modification of in-place page tables - tainting kernel\n");
+ add_taint(TAINT_CPU_OUT_OF_SPEC, LOCKDEP_STILL_OK);
+
+ /*
+ * Remap level 1 table. This changes the physical addresses
+ * used to refer to the level 2 page tables to the high
+ * physical address alias, leaving everything else the same.
+ */