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_ARM64_INSTRUCTION_SET_FEATURES_ARM64_H_ 18 #define ART_RUNTIME_ARCH_ARM64_INSTRUCTION_SET_FEATURES_ARM64_H_ 19 20 #include "arch/instruction_set_features.h" 21 22 namespace art { 23 24 // SVE is currently not enabled. 25 static constexpr bool kArm64AllowSVE = false; 26 27 class Arm64InstructionSetFeatures; 28 using Arm64FeaturesUniquePtr = std::unique_ptr<const Arm64InstructionSetFeatures>; 29 30 // Instruction set features relevant to the ARM64 architecture. 31 class Arm64InstructionSetFeatures final : public InstructionSetFeatures { 32 public: 33 // Process a CPU variant string like "krait" or "cortex-a15" and create InstructionSetFeatures. 34 static Arm64FeaturesUniquePtr FromVariant(const std::string& variant, std::string* error_msg); 35 36 // Parse a bitmap and create an InstructionSetFeatures. 37 static Arm64FeaturesUniquePtr FromBitmap(uint32_t bitmap); 38 39 // Turn C pre-processor #defines into the equivalent instruction set features. 40 static Arm64FeaturesUniquePtr FromCppDefines(); 41 42 // Process /proc/cpuinfo and use kRuntimeISA to produce InstructionSetFeatures. 43 static Arm64FeaturesUniquePtr FromCpuInfo(); 44 45 // Process the auxiliary vector AT_HWCAP entry and use kRuntimeISA to produce 46 // InstructionSetFeatures. 47 static Arm64FeaturesUniquePtr FromHwcap(); 48 49 // Use assembly tests of the current runtime (ie kRuntimeISA) to determine the 50 // InstructionSetFeatures. This works around kernel bugs in AT_HWCAP and /proc/cpuinfo. 51 static Arm64FeaturesUniquePtr FromAssembly(); 52 53 // Use external cpu_features library. 54 static Arm64FeaturesUniquePtr FromCpuFeatures(); 55 56 bool Equals(const InstructionSetFeatures* other) const override; 57 58 // Note that newer CPUs do not have a53 erratum 835769 and 843419, 59 // so the two a53 fix features (fix_cortex_a53_835769 and fix_cortex_a53_843419) 60 // are not tested for HasAtLeast. 61 bool HasAtLeast(const InstructionSetFeatures* other) const override; 62 GetInstructionSet()63 InstructionSet GetInstructionSet() const override { 64 return InstructionSet::kArm64; 65 } 66 67 uint32_t AsBitmap() const override; 68 69 // Return a string of the form "a53" or "none". 70 std::string GetFeatureString() const override; 71 72 // Generate code addressing Cortex-A53 erratum 835769? NeedFixCortexA53_835769()73 bool NeedFixCortexA53_835769() const { 74 return fix_cortex_a53_835769_; 75 } 76 77 // Generate code addressing Cortex-A53 erratum 843419? NeedFixCortexA53_843419()78 bool NeedFixCortexA53_843419() const { 79 return fix_cortex_a53_843419_; 80 } 81 HasCRC()82 bool HasCRC() const { 83 return has_crc_; 84 } 85 HasLSE()86 bool HasLSE() const { 87 return has_lse_; 88 } 89 HasFP16()90 bool HasFP16() const { 91 return has_fp16_; 92 } 93 94 // Are Dot Product instructions (UDOT/SDOT) available? HasDotProd()95 bool HasDotProd() const { 96 return has_dotprod_; 97 } 98 HasSVE()99 bool HasSVE() const { 100 return kArm64AllowSVE && has_sve_; 101 } 102 GetSVEVectorLength()103 size_t GetSVEVectorLength() const { 104 // TODO: support SVE vector length detection. 105 return kArm64DefaultSVEVectorLength; 106 } 107 ~Arm64InstructionSetFeatures()108 virtual ~Arm64InstructionSetFeatures() {} 109 110 protected: 111 // Parse a vector of the form "a53" adding these to a new ArmInstructionSetFeatures. 112 std::unique_ptr<const InstructionSetFeatures> 113 AddFeaturesFromSplitString(const std::vector<std::string>& features, 114 std::string* error_msg) const override; 115 116 std::unique_ptr<const InstructionSetFeatures> 117 AddRuntimeDetectedFeatures(const InstructionSetFeatures *features) const override; 118 119 private: Arm64InstructionSetFeatures(bool needs_a53_835769_fix,bool needs_a53_843419_fix,bool has_crc,bool has_lse,bool has_fp16,bool has_dotprod,bool has_sve)120 Arm64InstructionSetFeatures(bool needs_a53_835769_fix, 121 bool needs_a53_843419_fix, 122 bool has_crc, 123 bool has_lse, 124 bool has_fp16, 125 bool has_dotprod, 126 bool has_sve) 127 : InstructionSetFeatures(), 128 fix_cortex_a53_835769_(needs_a53_835769_fix), 129 fix_cortex_a53_843419_(needs_a53_843419_fix), 130 has_crc_(has_crc), 131 has_lse_(has_lse), 132 has_fp16_(has_fp16), 133 has_dotprod_(has_dotprod), 134 has_sve_(has_sve) { 135 } 136 137 // Bitmap positions for encoding features as a bitmap. 138 enum { 139 kA53Bitfield = 1 << 0, 140 kCRCBitField = 1 << 1, 141 kLSEBitField = 1 << 2, 142 kFP16BitField = 1 << 3, 143 kDotProdBitField = 1 << 4, 144 kSVEBitField = 1 << 5, 145 }; 146 147 const bool fix_cortex_a53_835769_; 148 const bool fix_cortex_a53_843419_; 149 const bool has_crc_; // optional in ARMv8.0, mandatory in ARMv8.1. 150 const bool has_lse_; // ARMv8.1 Large System Extensions. 151 const bool has_fp16_; // ARMv8.2 FP16 extensions. 152 const bool has_dotprod_; // optional in ARMv8.2, mandatory in ARMv8.4. 153 const bool has_sve_; // optional in ARMv8.2. 154 155 DISALLOW_COPY_AND_ASSIGN(Arm64InstructionSetFeatures); 156 }; 157 158 } // namespace art 159 160 #endif // ART_RUNTIME_ARCH_ARM64_INSTRUCTION_SET_FEATURES_ARM64_H_ 161