1 /* 2 * Copyright (C) 2011 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_INSTRUCTION_SET_FEATURES_H_ 18 #define ART_RUNTIME_ARCH_INSTRUCTION_SET_FEATURES_H_ 19 20 #include <iosfwd> 21 #include <memory> 22 #include <vector> 23 24 #include "arch/instruction_set.h" 25 #include "base/macros.h" 26 27 namespace art { 28 29 class ArmInstructionSetFeatures; 30 class Arm64InstructionSetFeatures; 31 class Riscv64InstructionSetFeatures; 32 class X86InstructionSetFeatures; 33 class X86_64InstructionSetFeatures; 34 35 // Abstraction used to describe features of a different instruction sets. 36 class InstructionSetFeatures { 37 public: 38 // Process a CPU variant string for the given ISA and create an InstructionSetFeatures. 39 static std::unique_ptr<const InstructionSetFeatures> FromVariant(InstructionSet isa, 40 const std::string& variant, 41 std::string* error_msg); 42 43 // Process a CPU variant string for the given ISA and make sure the features advertised 44 // are supported by the hardware. This is needed for Pixel3a which wrongly 45 // reports itself as cortex-a75. 46 static std::unique_ptr<const InstructionSetFeatures> FromVariantAndHwcap( 47 InstructionSet isa, const std::string& variant, std::string* error_msg); 48 49 // Parse a bitmap for the given isa and create an InstructionSetFeatures. 50 static std::unique_ptr<const InstructionSetFeatures> FromBitmap(InstructionSet isa, 51 uint32_t bitmap); 52 53 // Turn C pre-processor #defines into the equivalent instruction set features for kRuntimeISA. 54 static std::unique_ptr<const InstructionSetFeatures> FromCppDefines(); 55 56 // Check if run-time detection of instruction set features is supported. 57 // 58 // Return: true - if run-time detection is supported on a target device. 59 // false - otherwise IsRuntimeDetectionSupported()60 static bool IsRuntimeDetectionSupported() { 61 return FromRuntimeDetection() != nullptr; 62 } 63 64 // Use run-time detection to get instruction set features. 65 // 66 // Return: a set of detected features or nullptr if runtime detection is not 67 // supported on a target. 68 static std::unique_ptr<const InstructionSetFeatures> FromRuntimeDetection(); 69 70 // Process /proc/cpuinfo and use kRuntimeISA to produce InstructionSetFeatures. 71 static std::unique_ptr<const InstructionSetFeatures> FromCpuInfo(); 72 73 // Process the auxiliary vector AT_HWCAP entry and use kRuntimeISA to produce 74 // InstructionSetFeatures. 75 static std::unique_ptr<const InstructionSetFeatures> FromHwcap(); 76 77 // Use assembly tests of the current runtime (ie kRuntimeISA) to determine the 78 // InstructionSetFeatures. This works around kernel bugs in AT_HWCAP and /proc/cpuinfo. 79 static std::unique_ptr<const InstructionSetFeatures> FromAssembly(); 80 81 // Use external cpu_features library. 82 static std::unique_ptr<const InstructionSetFeatures> FromCpuFeatures(); 83 84 // Parse a string of the form "div,-atomic_ldrd_strd" adding and removing these features to 85 // create a new InstructionSetFeatures. 86 std::unique_ptr<const InstructionSetFeatures> AddFeaturesFromString( 87 const std::string& feature_list, std::string* error_msg) const WARN_UNUSED; 88 89 // Are these features the same as the other given features? 90 virtual bool Equals(const InstructionSetFeatures* other) const = 0; 91 92 // For testing purposes we want to make sure that the system we run on has at 93 // least the options we claim it has. In this cases Equals() does not 94 // suffice and will cause the test to fail, since the runtime cpu feature 95 // detection claims more capabilities then statically specified from the 96 // build system. 97 // 98 // A good example of this is the armv8 ART test target that declares 99 // "CPU_VARIANT=generic". If the generic target is specified and the code 100 // is run on a platform with enhanced capabilities, the 101 // instruction_set_features test will fail if we resort to using Equals() 102 // between statically defined cpu features and runtime cpu features. 103 // 104 // For now we default this to Equals() in case the architecture does not 105 // provide it. HasAtLeast(const InstructionSetFeatures * other)106 virtual bool HasAtLeast(const InstructionSetFeatures* other) const { 107 return Equals(other); 108 } 109 110 // Return the ISA these features relate to. 111 virtual InstructionSet GetInstructionSet() const = 0; 112 113 // Return a bitmap that represents the features. ISA specific. 114 virtual uint32_t AsBitmap() const = 0; 115 116 // Return a string of the form "div,lpae" or "none". 117 virtual std::string GetFeatureString() const = 0; 118 119 // Down cast this ArmInstructionFeatures. 120 const ArmInstructionSetFeatures* AsArmInstructionSetFeatures() const; 121 122 // Down cast this Arm64InstructionFeatures. 123 const Arm64InstructionSetFeatures* AsArm64InstructionSetFeatures() const; 124 125 // Down cast this Riscv64InstructionFeatures. 126 const Riscv64InstructionSetFeatures* AsRiscv64InstructionSetFeatures() const; 127 128 // Down cast this X86InstructionFeatures. 129 const X86InstructionSetFeatures* AsX86InstructionSetFeatures() const; 130 131 // Down cast this X86_64InstructionFeatures. 132 const X86_64InstructionSetFeatures* AsX86_64InstructionSetFeatures() const; 133 ~InstructionSetFeatures()134 virtual ~InstructionSetFeatures() {} 135 136 protected: InstructionSetFeatures()137 InstructionSetFeatures() {} 138 139 // Returns true if variant appears in the array variants. 140 static bool FindVariantInArray(const char* const variants[], size_t num_variants, 141 const std::string& variant); 142 143 // Add architecture specific features in sub-classes. 144 virtual std::unique_ptr<const InstructionSetFeatures> 145 AddFeaturesFromSplitString(const std::vector<std::string>& features, 146 std::string* error_msg) const = 0; 147 148 // Add run-time detected architecture specific features in sub-classes. 149 virtual std::unique_ptr<const InstructionSetFeatures> 150 AddRuntimeDetectedFeatures(const InstructionSetFeatures *features ATTRIBUTE_UNUSED) const; 151 152 private: 153 DISALLOW_COPY_AND_ASSIGN(InstructionSetFeatures); 154 }; 155 std::ostream& operator<<(std::ostream& os, const InstructionSetFeatures& rhs); 156 157 } // namespace art 158 159 #endif // ART_RUNTIME_ARCH_INSTRUCTION_SET_FEATURES_H_ 160