Home | History | Annotate | Download | only in arm 
      1 /*
      2  * Copyright (C) 2014 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 #ifndef ART_RUNTIME_ARCH_ARM_INSTRUCTION_SET_FEATURES_ARM_H_
     18 #define ART_RUNTIME_ARCH_ARM_INSTRUCTION_SET_FEATURES_ARM_H_
     19 
     20 #include "arch/instruction_set_features.h"
     21 
     22 namespace art {
     23 
     24 // Instruction set features relevant to the ARM architecture.
     25 class ArmInstructionSetFeatures FINAL : public InstructionSetFeatures {
     26  public:
     27   // Process a CPU variant string like "krait" or "cortex-a15" and create InstructionSetFeatures.
     28   static const ArmInstructionSetFeatures* FromVariant(const std::string& variant,
     29                                                       std::string* error_msg);
     30 
     31   // Parse a bitmap and create an InstructionSetFeatures.
     32   static const ArmInstructionSetFeatures* FromBitmap(uint32_t bitmap);
     33 
     34   // Turn C pre-processor #defines into the equivalent instruction set features.
     35   static const ArmInstructionSetFeatures* FromCppDefines();
     36 
     37   // Process /proc/cpuinfo and use kRuntimeISA to produce InstructionSetFeatures.
     38   static const ArmInstructionSetFeatures* FromCpuInfo();
     39 
     40   // Process the auxiliary vector AT_HWCAP entry and use kRuntimeISA to produce
     41   // InstructionSetFeatures.
     42   static const ArmInstructionSetFeatures* FromHwcap();
     43 
     44   // Use assembly tests of the current runtime (ie kRuntimeISA) to determine the
     45   // InstructionSetFeatures. This works around kernel bugs in AT_HWCAP and /proc/cpuinfo.
     46   static const ArmInstructionSetFeatures* FromAssembly();
     47 
     48   bool Equals(const InstructionSetFeatures* other) const OVERRIDE;
     49 
     50   InstructionSet GetInstructionSet() const OVERRIDE {
     51     return kArm;
     52   }
     53 
     54   uint32_t AsBitmap() const OVERRIDE;
     55 
     56   // Return a string of the form "div,lpae" or "none".
     57   std::string GetFeatureString() const OVERRIDE;
     58 
     59   // Is the divide instruction feature enabled?
     60   bool HasDivideInstruction() const {
     61       return has_div_;
     62   }
     63 
     64   // Are the ldrd and strd instructions atomic? This is commonly true when the Large Physical
     65   // Address Extension (LPAE) is present.
     66   bool HasAtomicLdrdAndStrd() const {
     67     return has_atomic_ldrd_strd_;
     68   }
     69 
     70   virtual ~ArmInstructionSetFeatures() {}
     71 
     72  protected:
     73   // Parse a vector of the form "div", "lpae" adding these to a new ArmInstructionSetFeatures.
     74   const InstructionSetFeatures*
     75       AddFeaturesFromSplitString(const bool smp, const std::vector<std::string>& features,
     76                                  std::string* error_msg) const OVERRIDE;
     77 
     78  private:
     79   ArmInstructionSetFeatures(bool smp, bool has_div, bool has_atomic_ldrd_strd)
     80       : InstructionSetFeatures(smp),
     81         has_div_(has_div), has_atomic_ldrd_strd_(has_atomic_ldrd_strd) {
     82   }
     83 
     84   // Bitmap positions for encoding features as a bitmap.
     85   enum {
     86     kSmpBitfield = 1,
     87     kDivBitfield = 2,
     88     kAtomicLdrdStrdBitfield = 4,
     89   };
     90 
     91   const bool has_div_;
     92   const bool has_atomic_ldrd_strd_;
     93 
     94   DISALLOW_COPY_AND_ASSIGN(ArmInstructionSetFeatures);
     95 };
     96 
     97 }  // namespace art
     98 
     99 #endif  // ART_RUNTIME_ARCH_ARM_INSTRUCTION_SET_FEATURES_ARM_H_
    100