Rewrite non-temporal instructions

src/trusted/validator/validation_rewrite_32_test.cc

 /*
  * Copyright 2015 The Native Client Authors. All rights reserved.
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
+#include <string.h>
 #include "gtest/gtest.h"
 
 #include "native_client/src/shared/platform/nacl_log.h"
 #include "native_client/src/shared/utils/types.h"
 #include "native_client/src/trusted/validator/ncvalidate.h"
 
 #define CODE_SIZE 32
 #define NOP 0x90
-#define MOVNTI_CODE_SIZE 8
 
-// mov %edi,%edi; movnti %rax,0x68(%r15,%rdi,1)
-const char* movnti_code = "\x89\xff\x49\x0f\xc3\x44\x3f\x68";
-
-class ValidationDisableNonTemporalsTests : public ::testing::Test {
+class ValidationMovntRewriteTests : public ::testing::Test {
  protected:
   NaClValidationMetadata *metadata_ptr;
   const struct NaClValidatorInterface *validator;
   NaClCPUFeatures *cpu_features;
 
   unsigned char code_buffer[CODE_SIZE];
 
   void SetUp() {
     metadata_ptr = NULL;
     validator = NaClCreateValidator();
@@ skipping 12 matching lines @@
                                cpu_features,
                                metadata_ptr,
                                NULL);
   }
 
   void TearDown() {
     free(cpu_features);
   }
 };
 
-TEST_F(ValidationDisableNonTemporalsTests, NotDisableNonTemporals) {
-  memcpy(code_buffer, movnti_code, MOVNTI_CODE_SIZE);
-  NaClValidationStatus status = Validate(0);
-  // If we are not disabling non-temporal instructions, use the original
-  // validation rule, i.e., allow them. In future, we will do rewriting.
-  EXPECT_EQ(NaClValidationSucceeded, status);
+TEST_F(ValidationMovntRewriteTests, DisableNonTemporalsNoRewrite) {
+  // movntq %mm0, (%ebx)
+  const char *code = "\x0f\xe7\x03";

[bradn, 2015/08/04 22:03:30]

Could you add a .S file with the asm for each of these, but in a data region.
You'd do something like:

.data
.global DisableNonTemporalsNoRewrite_code
DisableNonTemporalsNoRewrite_code:
  movntq %mm0, (%ebx)
  .byte 0
Then use that in place of the code variable.

[ruiq, 2015/08/05 20:11:02]

Done.

+  memcpy(code_buffer, code, strlen(code));
+  NaClValidationStatus status = Validate(NACL_DISABLE_NONTEMPORALS_X86);
+  // Disable nontemporals, no rewrite.
+  EXPECT_EQ(NaClValidationFailed, status);
   // Code should not change.
-  EXPECT_EQ(0, memcmp(code_buffer, movnti_code, MOVNTI_CODE_SIZE));
+  EXPECT_EQ(0, memcmp(code_buffer, code, strlen(code)));
 }
 
-TEST_F(ValidationDisableNonTemporalsTests, DisableNonTemporals) {
-  memcpy(code_buffer, movnti_code, MOVNTI_CODE_SIZE);
-  NaClValidationStatus status = Validate(NACL_DISABLE_NONTEMPORALS_X86);
-  // Disable non-temporal instructions.
-  EXPECT_EQ(NaClValidationFailed, status);
-  // Code should not change.
-  EXPECT_EQ(0, memcmp(code_buffer, movnti_code, MOVNTI_CODE_SIZE));
+TEST_F(ValidationMovntRewriteTests, RewriteMovntq) {
+  // movntq %mm0, (%ebx)
+  const char *code = "\x0f\xe7\x03";
+  memcpy(code_buffer, code, strlen(code));
+  NaClValidationStatus status = Validate(0);
+  EXPECT_EQ(NaClValidationSucceeded, status);
+  // movq %mm0, (%ebx)
+  const char *expect_code = "\x0f\x7f\x03";
+  EXPECT_EQ(0, memcmp(code_buffer, expect_code, strlen(expect_code)));
+}
+
+TEST_F(ValidationMovntRewriteTests, RewriteMovntdq) {
+  // movntdq %xmm0, (%edx)
+  const char *code = "\x66\x0f\xe7\x02";
+  memcpy(code_buffer, code, strlen(code));
+  NaClValidationStatus status = Validate(0);
+  EXPECT_EQ(NaClValidationSucceeded, status);
+  // movdqa %xmm0, (%edx)
+  const char *expect_code = "\x66\x0f\x7f\x02";
+  EXPECT_EQ(0, memcmp(code_buffer, expect_code, strlen(expect_code)));
 }
 
 int main(int argc, char *argv[]) {
   // The IllegalInst test touches the log mutex deep inside the validator.
   // This causes an SEH exception to be thrown on Windows if the mutex is not
   // initialized.
   // http://code.google.com/p/nativeclient/issues/detail?id=1696
   NaClLogModuleInit();
   testing::InitGoogleTest(&argc, argv);
   return RUN_ALL_TESTS();
 }