Disable Poly1305 code only on bad chips.

base/cpu.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef BASE_CPU_H_
 #define BASE_CPU_H_
 
 #include <string>
 
 #include "base/base_export.h"
@@ skipping 38 matching lines @@
   // has_avx_hardware returns true when AVX is present in the CPU. This might
   // differ from the value of |has_avx()| because |has_avx()| also tests for
   // operating system support needed to actually call AVX instuctions.
   // Note: you should never need to call this function. It was added in order
   // to workaround a bug in NSS but |has_avx()| is what you want.
   bool has_avx_hardware() const { return has_avx_hardware_; }
   bool has_aesni() const { return has_aesni_; }
   bool has_non_stop_time_stamp_counter() const {
     return has_non_stop_time_stamp_counter_;
   }
+  // has_broken_neon is only valid on ARM chips. If true, it indicates that we
+  // believe that the NEON unit on the current CPU is flawed and cannot execute
+  // some code. See https://code.google.com/p/chromium/issues/detail?id=341598
+  bool has_broken_neon() const { return has_broken_neon_; }
+
   IntelMicroArchitecture GetIntelMicroArchitecture() const;
   const std::string& cpu_brand() const { return cpu_brand_; }
 
  private:
   // Query the processor for CPUID information.
   void Initialize();
 
   int signature_;  // raw form of type, family, model, and stepping
   int type_;  // process type
   int family_;  // family of the processor
   int model_;  // model of processor
   int stepping_;  // processor revision number
   int ext_model_;
   int ext_family_;
   bool has_mmx_;
   bool has_sse_;
   bool has_sse2_;
   bool has_sse3_;
   bool has_ssse3_;
   bool has_sse41_;
   bool has_sse42_;
   bool has_avx_;
   bool has_avx_hardware_;
   bool has_aesni_;
   bool has_non_stop_time_stamp_counter_;
+  bool has_broken_neon_;
   std::string cpu_vendor_;
   std::string cpu_brand_;
 };
 
 }  // namespace base
 
 #endif  // BASE_CPU_H_