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

src/trusted/service_runtime/sys_memory.c

 /*
  * Copyright (c) 2013 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 "native_client/src/trusted/service_runtime/sys_memory.h"
 
 #include <errno.h>
 #include <string.h>
@@ skipping 249 matching lines @@
   uintptr_t                   endaddr;
   int                         mapping_code;
   uintptr_t                   map_result;
   int                         holding_app_lock;
   struct nacl_abi_stat        stbuf;
   size_t                      alloc_rounded_length;
   nacl_off64_t                file_size;
   nacl_off64_t                file_bytes;
   nacl_off64_t                host_rounded_file_bytes;
   size_t                      alloc_rounded_file_bytes;
+  uint32_t                    val_flags;
 
   holding_app_lock = 0;
   ndp = NULL;
 
   allowed_flags = (NACL_ABI_MAP_FIXED | NACL_ABI_MAP_SHARED
                    | NACL_ABI_MAP_PRIVATE | NACL_ABI_MAP_ANONYMOUS);
 
   usraddr = (uintptr_t) start;
 
   if (0 != (flags & ~allowed_flags)) {
@@ skipping 434 matching lines @@
                              (void *) NULL,
                              length,
                              NACL_ABI_PROT_READ | NACL_ABI_PROT_WRITE,
                              NACL_ABI_MAP_PRIVATE,
                              offset);
       if (NaClPtrIsNegErrno(&image_sys_addr)) {
         map_result = image_sys_addr;
         goto cleanup;
       }
 
+      val_flags = nap->pnacl_mode ? DISABLE_NONTEMPORALS : 0;
       /* Ask validator / validation cache */
       NaClMetadataFromNaClDescCtor(&metadata, ndp);
       validator_status = NACL_FI("MMAP_FORCE_MMAP_VALIDATION_FAIL",
                                  (*nap->validator->
                                   Validate)(usraddr,
                                             (uint8_t *) image_sys_addr,
                                             length,
                                             0,  /* stubout_mode: no */
+                                            val_flags,
                                             1,  /* readonly_text: yes */
                                             nap->cpu_features,
                                             &metadata,
                                             nap->validation_cache),
                                  NaClValidationFailed);
       NaClLog(3, "NaClSysMmap: prot_exec, validator_status %d\n",
               validator_status);
       NaClMetadataDtor(&metadata);
 
       if (NaClValidationSucceeded == validator_status) {
@@ skipping 623 matching lines @@
                         size_t                length,
                         int                   prot) {
   struct NaClApp  *nap = natp->nap;
 
   NaClLog(3, "Entered NaClSysMprotect(0x%08"NACL_PRIxPTR", "
           "0x%08"NACL_PRIxPTR", 0x%"NACL_PRIxS", 0x%x)\n",
           (uintptr_t) natp, (uintptr_t) start, length, prot);
 
   return NaClSysMprotectInternal(nap, start, length, prot);
 }