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/*
* Copyright (C) 2014 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef ART_RUNTIME_ARCH_ARM64_INSTRUCTION_SET_FEATURES_ARM64_H_
#define ART_RUNTIME_ARCH_ARM64_INSTRUCTION_SET_FEATURES_ARM64_H_
#include "arch/instruction_set_features.h"
namespace art {
// Instruction set features relevant to the ARM64 architecture.
class Arm64InstructionSetFeatures FINAL : public InstructionSetFeatures {
public:
// Process a CPU variant string like "krait" or "cortex-a15" and create InstructionSetFeatures.
static const Arm64InstructionSetFeatures* FromVariant(const std::string& variant,
std::string* error_msg);
// Parse a bitmap and create an InstructionSetFeatures.
static const Arm64InstructionSetFeatures* FromBitmap(uint32_t bitmap);
// Turn C pre-processor #defines into the equivalent instruction set features.
static const Arm64InstructionSetFeatures* FromCppDefines();
// Process /proc/cpuinfo and use kRuntimeISA to produce InstructionSetFeatures.
static const Arm64InstructionSetFeatures* FromCpuInfo();
// Process the auxiliary vector AT_HWCAP entry and use kRuntimeISA to produce
// InstructionSetFeatures.
static const Arm64InstructionSetFeatures* FromHwcap();
// Use assembly tests of the current runtime (ie kRuntimeISA) to determine the
// InstructionSetFeatures. This works around kernel bugs in AT_HWCAP and /proc/cpuinfo.
static const Arm64InstructionSetFeatures* FromAssembly();
bool Equals(const InstructionSetFeatures* other) const OVERRIDE;
InstructionSet GetInstructionSet() const OVERRIDE {
return kArm64;
}
uint32_t AsBitmap() const OVERRIDE;
// Return a string of the form "a53" or "none".
std::string GetFeatureString() const OVERRIDE;
// Generate code addressing Cortex-A53 erratum 835769?
bool NeedFixCortexA53_835769() const {
return fix_cortex_a53_835769_;
}
// Generate code addressing Cortex-A53 erratum 843419?
bool NeedFixCortexA53_843419() const {
return fix_cortex_a53_843419_;
}
// NOTE: This flag can be tunned on a CPU basis. In general all ARMv8 CPUs
// should prefer the Acquire-Release semantics over the explicit DMBs when
// handling load/store-volatile. For a specific use case see the ARM64
// Optimizing backend.
bool PreferAcquireRelease() const {
return true;
}
virtual ~Arm64InstructionSetFeatures() {}
protected:
// Parse a vector of the form "a53" adding these to a new ArmInstructionSetFeatures.
const InstructionSetFeatures*
AddFeaturesFromSplitString(const bool smp, const std::vector<std::string>& features,
std::string* error_msg) const OVERRIDE;
private:
Arm64InstructionSetFeatures(bool smp, bool needs_a53_835769_fix, bool needs_a53_843419_fix)
: InstructionSetFeatures(smp),
fix_cortex_a53_835769_(needs_a53_835769_fix),
fix_cortex_a53_843419_(needs_a53_843419_fix) {
}
// Bitmap positions for encoding features as a bitmap.
enum {
kSmpBitfield = 1,
kA53Bitfield = 2,
};
const bool fix_cortex_a53_835769_;
const bool fix_cortex_a53_843419_;
DISALLOW_COPY_AND_ASSIGN(Arm64InstructionSetFeatures);
};
} // namespace art
#endif // ART_RUNTIME_ARCH_ARM64_INSTRUCTION_SET_FEATURES_ARM64_H_