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 1ad2a9ac40c3717581ea6303b218e3ffda79ad9d..ad80d695333aeeb2c5bcf0f456cf5483cb576aae 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);
+  UNREFERENCED_PARAMETER(flags);

[JF, 2015/07/29 00:08:02]

I'd rather CHECK(flags == 0);

[ruiq, 2015/07/29 00:14:17]

Done.

[Mark Seaborn, 2015/07/29 00:31:39]

Won't that fail when running PNaCl apps inside Chrome on ARM?  The code is
currently passing non-zero flags for all architectures when running PNaCl.

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