A mechanism to identify/forbid/"rewrite" non-temporal instructions (and other)

src/trusted/validator_arm/ncvalidate.cc

Index: src/trusted/validator_arm/ncvalidate.cc
diff --git a/src/trusted/validator_arm/ncvalidate.cc b/src/trusted/validator_arm/ncvalidate.cc
index e4830903b3384d9da07aff899234f4b09964792f..4afdd6d4c32fa8937fe7682574b3a9d7eb27b216 100644
--- a/src/trusted/validator_arm/ncvalidate.cc
+++ b/src/trusted/validator_arm/ncvalidate.cc
@@ -143,12 +143,14 @@ static NaClValidationStatus ApplyValidatorArm(
     uint8_t *data,
     size_t size,
     int stubout_mode,
+    uint32_t flags,
     int readonly_text,
     const NaClCPUFeatures *cpu_features,
     const struct NaClValidationMetadata *metadata,
     struct NaClValidationCache *cache) {
   // The ARM validator never modifies the text, so this flag can be ignored.
   UNREFERENCED_PARAMETER(readonly_text);
+  CHECK((flags & ARM_VALIDATION_FLAGS_MASK) == 0);

[Mark Seaborn, 2015/07/29 16:09:23]

What's the purpose of this, given that ARM_VALIDATION_FLAGS_MASK is 0?

Are you using X86_VALIDATION_FLAGS_MASK?  I didn't see a use of it (though it's
hard to search because Rietveld won't let me download the patch).

   CheckAddressAlignAndOverflow((uint8_t *) guest_addr, size);
   CheckAddressOverflow(data, size);
   CheckAddressOverflow(data, size);