Rewrite non-temporal instructions

src/trusted/validator_ragel/dfa_validate_64.c

Index: src/trusted/validator_ragel/dfa_validate_64.c
diff --git a/src/trusted/validator_ragel/dfa_validate_64.c b/src/trusted/validator_ragel/dfa_validate_64.c
index f91d36fe95be581edacec83c3c3a303e2dec2f6e..13aa6a5aaa234d2390ae5f353d95493dda8e181d 100644
--- a/src/trusted/validator_ragel/dfa_validate_64.c
+++ b/src/trusted/validator_ragel/dfa_validate_64.c
@@ -39,9 +39,9 @@ static NaClValidationStatus ApplyDfaValidator_x86_64(
   NaClCPUFeaturesX86 *cpu_features = (NaClCPUFeaturesX86 *) f;
   enum NaClValidationStatus status = NaClValidationFailed;
   void *query = NULL;
+  uint32_t options;
   struct StubOutCallbackData callback_data;
-  callback_data.flags = flags;
-  callback_data.did_rewrite = 0;
+
   UNREFERENCED_PARAMETER(guest_addr);
 
   if (stubout_mode)
@@ -68,13 +68,21 @@ static NaClValidationStatus ApplyDfaValidator_x86_64(
     }
   }
 
+  options = 0;
+  callback_data.flags = flags;
+  callback_data.chunk_processed_as_a_contiguous_stream =
+    options & PROCESS_CHUNK_AS_A_CONTIGUOUS_STREAM;
+  callback_data.bundle_begin_offset = (uintptr_t) data & kBundleMask;

[Mark Seaborn, 2015/08/14 21:12:59]

I'm not sure I understand this parameter.  You're taking a trusted address and
ANDing it with kBundleMask?  That seems like a very hacky thing to do.

[Mark Seaborn, 2015/08/21 21:13:32]

This will need to get addressed...

I will take over this change and do some further cleanups in order to get it
committed.

[QiaoRuiwhu, 2015/08/24 19:48:15]

This is because the 'data' argument, which is the pointer to code_to_verify, is
not necessarily kBundleSize aligned. At least some callers of
ApplyDfaValidator_x86_64() function do not pass in an aligned pointer. Note that
ValidateChunkAMD64() does not enforce 'data' argument to be kBundleSize aligned
either, although it validates bundle by bundle, starting from 'data'.

I suspect the decision of not enforcing 'data' to be kBundleSize aligned was
made on purpose. This is useful, for example, when user supplies some code
buffer (not aligned) which is used only for validation, and later the code can
be copied to code region (aligned) for execution.

If this is not true, we could potentially change all callers to align 'data'
argument before passing in.

An alternative of computing the offset inside a bundle (current approach) is to
pass the offset in as an additional argument. However, this requires function
interface change.

Hopefuly above explanation clarifies a little bit.

+  callback_data.cpu_features = cpu_features;
+  callback_data.did_rewrite = 0;
+
   if (readonly_text) {
-    if (ValidateChunkAMD64(data, size, 0 /*options*/, cpu_features,
+    if (ValidateChunkAMD64(data, size, options, cpu_features,
                            NaClDfaProcessValidationError,
                            NULL))
       status = NaClValidationSucceeded;
   } else {
-    if (ValidateChunkAMD64(data, size, 0 /*options*/, cpu_features,
+    if (ValidateChunkAMD64(data, size, options, cpu_features,
                            NaClDfaStubOutUnsupportedInstruction,
                            &callback_data))
       status = NaClValidationSucceeded;