《Perforce：汽車軟件開發指南（英文版）（11頁）.pdf》由會員分享，可在線閱讀，更多相關《Perforce：汽車軟件開發指南（英文版）（11頁）.pdf（11頁珍藏版）》請在三個皮匠報告上搜索。

1、 Perforce Software,Inc.All trademarks and registered trademarks are the property of their respective owners.(0220RB21)IntroductionThe automotive software development process can be complex and time-consuming,which is why it is important to use the right software development tools and follow best pra

2、ctices for automotive software development.By doing so,you are able to ensure secure,reliable,and standards-compliant automotive software.Here,we provide an overview of the key automotive software standards that you should use,the best practices to safeguard against security threats,and touch on aut

3、onomous vehicles and smart car features.WHITE PAPERGuide to Automotive Software Development:Automotive Standards,Security,and Emerging T Perforce Software,Inc.All trademarks and registered trademarks are the property of their respective owners.(0220RB21)WHITE PAPER2|Guide to Automotive Software Deve

4、lopmentTable of ContentsOverview of Automotive Standards.3Coding Guidelines.3MISRA.3AUTOSAR C+14.3How to Achieve Coding Standard Compliance.3ISO 26262 and ASIL Automotive Functional Safety.4Motorcycle Standards for Functional Safety.6ISO 21434 Automotive Software Security.7ISO/PAS 21448 Safety In Au

5、tonomous Driving.7 The Essential Automotive Software Quality Metrics.8The Future of Automotive Software D Perforce Software,Inc.All trademarks and registered trademarks are the property of their respective owners.(0220RB21)WHITE PAPER3|Guide to Automotive Software DevelopmentOverview of Automotive S

6、tandardsAll vehicles are governed by standards.These include functional safety standards and functional security standards and these in turn require the use of coding guidelines for the development of the many software components in the vehicle.Overview of Coding GuidelinesAlthough no function safet

7、y or security standard specifies a particular coding standard,there are internationally recognized coding guidelines available to help meet the required security and safety standards.MISRAMISRA,originally written for the automotive industry,provides coding standards for developing safety-critical sy

8、stems.The initial version,published in 1998 was for C,and this was then extended to C+in 2008.MISRA C is the most widely used set of coding guidelines for C around the world.The most recent version of the standard is MISRA C:2012.MISRA C+is widely used by safety-critical developers.The current versi

9、on was published in 2008 but an update is forthcoming in the near future.MISRA coding guidelines are now widely used by industries such as aerospace and defense,telecommunications,medical devices,and rail as well as automotiveAUTOSAR C+14The AUTOSAR coding guidelines are for the use of the C+14 lang

10、uage in critical and safety-related systems.They were developed for use in the AUTOSAR Adaptive Platform,but are applicable to any safety-critical applications written in C+.Since MISRA C+was published,C+has evolved and other C+coding guidelines are available,for example HIC+,CERT C+,and C+Core Guid

11、elines.AUTOSAR C+14 addresses these changes and incorporates the expert knowledge embedded in these other coding standards.AUTOSAR C+14 is based on MISRA C+:2008 coding guidelines but with the addition of the best features of other C+coding standards,such as JSF and CERT C+.The standard allows the u

12、se of some features that are not permitted by other C+coding standards,including:Dynamic memory Exceptions Templates Inheritance Virtual functionsHow to Achieve Coding Standard ComplianceAchieving compliance to any coding standard takes knowledge,skill,and the right tools.Here are seven recommended

13、steps to achieve compliance: Perforce Software,Inc.All trademarks and registered trademarks are the property of their respective owners.(0220RB21)WHITE PAPER4|Guide to Automotive Software Development1.Know the Rules You need to know the coding rules pertinent to which version of C or C+youre using.2

14、.Check Your Code Constantly Continuously inspecting your code for violations is the best way to improve quality.3.Set Baselines Embedded systems come with legacy codebases.By setting baselines,you can focus on making sure your new code is compliant.4.Prioritize Violations Based on Risk You could hav

15、e hundreds or even thousands of violations in your code.Thats why its important to prioritize rule violations based on risk severity.Some static code analysis tools can do this for you.5.Document Your Deviations Sometimes there are exceptions to the rule.But when it comes to compliance,every rule de

16、viation needs to be well-documented.6.Monitor Your Compliance Keep an eye on how compliant your code is.Using a static code analyzer makes this easier by automatically generating a compliance report.7.Choose the Right Static Code Analyzer Choosing the right static code analyzer makes everything else

17、 easy.It takes care of scanning your code new and legacy for violations.It prioritizes vulnerabilities based on risk.ISO 26262 and ASIL:Automotive Functional SafetyISO 26262-“Road vehicles functional safety”,is the major functional safety standard used in the automotive industry,and ASIL is a key co

18、mponent to determine safety requirements for software development.It is a risk-based safety standard and applies to electric and/or electronic systems in production vehicles.This includes driver assistance,propulsion,and vehicle dynamics control systems.It covers the functional safety aspects of the

19、 entire development process:Requirements specification Design Implementation Integration Verification Validation ConfigurationWHY IS ISO 26262 IMPORTANT?The goal of the standard is to ensure safety throughout the lifecycle of automotive equipment and systems.Specific steps are required in each phase

20、.This ensures safety from the earliest concept to the point when the vehicle is retired.Compliance to this standard is compulsory for any road vehicle and by complying,youll avoid or control systematic failures,detect or control random hardware failures and be able to mitigate the effects of failure

21、.ISO 26262 FUNCTIONAL SAFETY FOR SOFTWARE DEVELOPERSPart 6:Product development at the software level and Part 8:Supporting processes are the sections applicable to software development.They detail the steps that must be taken to ensure the safety of each component.WHAT IS ASIL?Automotive Safety Inte

22、grity Level(ASIL)is a key element of ISO 26262 and it is used to measure the risk of a specific system component.The more complex the system,the greater the risk of systematic failures and random hardware Perforce Software,Inc.All trademarks and registered trademarks are the property of their respec

23、tive owners.(0220RB21)WHITE PAPER5|Guide to Automotive Software DevelopmentThere are four Automotive Safety Integrity Level values,AD where ASIL A is the minimum level of risk and ASIL D is the maximum.Compliance requirements become stricter as you go from A to D.There is an additional option QM(qua

24、lity management)which is used to note that there isnt a safety requirement for that component.HOW TO DETERMINE ASIL?ASIL is determined by three factors severity,exposure,and controllability.SEVERITYSeverity measures how serious the damages are of a system failure.Damages include both people and prop

25、erty.There are four classes of severity:1.S0:No injuries.2.S1:Light to moderate injuries.3.S2:Severe to life-threatening(survival probable)injuries.4.S3:Life-threatening(survival uncertain)to fatal injuries.EXPOSUREExposure is the likelihood of the conditions under which a particular failure would r

26、esult in a safety hazard.The probability of each condition is ranked on five-point scale:5.E0:Incredibly unlikely.6.E1:Very low probability(injury could happen only in rare operating conditions).7.E2:Low probability.8.E3:Medium probability.9.E4:High probability(injury could happen under most operati

27、ng conditions).CONTROLLABILITYControllability is a measure of the probability that harm can be avoided when a hazardous condition occurs.This condition might be due to actions by the driver or by external measures.The controllability of a hazardous situation is ranked on a four-point scale:10.C0:Con

28、trollable in general.11.C1:Simply controllable.12.C2:Normally controllable(most drivers could act to prevent injury).13.C3:Difficult to control or uncontrollable.HOW TO DETERMINE ASILOnce youve determined severity,probability,and controllability,you can determine the Automotive Safety Integrity Leve

29、l.Table 4 of Part 3 provides guidance on Perforce Software,Inc.All trademarks and registered trademarks are the property of their respective owners.(0220RB21)WHITE PAPER6|Guide to Automotive Software DevelopmentHOW TO COMPLY WITH ISO 26262Compliance with the safety standard is important,whether your

30、e developing traditional automotive components(e.g.,integrated circuits)or virtual ones(e.g.,automotive hypervisors).And its critical to maintain compliance throughout your software development lifecycle.But complying can be difficult for development teams.Systems and codebases grow complex.And that

31、 makes it difficult to verify and validate software.You can make it easier by using certified software development tools.ESTABLISH TRACEABILITYFulfilling compliance requirements and proving you met them is a tedious process.You need to document the requirements and trace them to other artifacts incl

32、uding tests,issues,and source code.Establishing requirements traceability makes your verification process easier,and it helps you manage risk in the development process.Storing your code in a version control system securely manages revision history for all your digital assets.Youll get fine-grained

33、access controls,high-visibility audit logs,strong password security,and secure replication.So,you can be confident in your code.APPLY A CODING STANDARDISO26262 requires that a coding standard is applied which will allow fulfill specific coding and design guidelines.Applying a coding standard,such as

34、 MISRA or AUTOSAR,is made easier by use a static analyzer.MOTORCYCLE STANDARDS FOR FUNCTIONAL SAFETYThe first edition of ISO 26262,published in 2011,covered series production passenger cars.While much of the guidance contained within this standard was also relevant to motorcycles,the hazard analysis

35、 and risk assessment for motorcycles required a different approach.Therefore,the scope of the second edition of ISO 26262,published in 2018,was extended to provide guidance to motorcycle manufacturers.Part 12,“Adaption of ISO 26262 for Motorcycles”was added which places more responsibility on the mo

36、torcyclist rather than the motorcycle to mitigate risks.To better assign safety criticality to a system,the Motorcycle Safety Integrity Levels(MSIL)were developed.They are determined by the same factors as ASIL and are assigned the same values,A-D,but include elements that are specific to motorcycle

37、 applications.Once the MSIL has been determined,it can be mapped to an equivalent ASIL:MSILASILQMQMAQMBACBCCThis then allows motorcycle applications to be developed according to the aligned ASIL with only some minor Perforce Software,Inc.All trademarks and registered trademarks are the property of t

38、heir respective owners.(0220RB21)WHITE PAPER7|Guide to Automotive Software DevelopmentISO/PAS 21448 Safety In Autonomous DrivingISO/PAS 21448 Road Vehicles Safety of the Intended Functionality(SOTIF)applies to functionality that requires proper situational awareness in order to be safe.The standard

39、is concerned with guaranteeing safety of the intended functionality SOTIF in the absence of a fault.This is in contrast with traditional functional safety,which is concerned with mitigating risk due to system failure.SOTIF provides guidance on design,verification,and validation measures.Applying the

40、se measures helps you achieve safety in situations without failure.For example:Design measure example:requirement for sensor performance.Verification measure example:test cases with high coverage of scenarios.Validation measure example:simulations.WHY SOTIF IS IMPORTANTAutomated systems have huge vo

41、lumes of data and that data is fed to complex algorithms.AI and machine learning are critical for developing these systems.To avoid potential safety hazards,AI will need to make decisions.This includes scenarios that require situational awareness.Using ISO 21448 will be key to ensure that AI is able

42、 to make decisions and avoid safety hazards.For example:The road is icy.An AI-based system might be unable to comprehend the situation and respond properly.This impacts the vehicles ability to operate safely.Without sensing the icy road condition,a self-driving vehicle might drive at a faster speed

43、than is safe for the condition.Fulfilling ISO 21448 means taking that situation into account and making decisions based on probability.The goal of SOTIF is to reduce potential unknown,unsafe conditions.HOW ISO 21448 IS RELATED TO ISO 26262Although ISO 26262 covers functional safety in the event of s

44、ystem failures,it doesnt cover safety hazards that dont lead to a system failure.ISO 26262 still applies to existing,established systems such as dynamic stability control(DSC)systems or airbags.For these systems,safety is ensured by mitigating the risk of system failure.ISO 21448 applies to systems

45、such as emergency intervention systems and advanced driver assistance systems.These systems could have safety hazards without system failure.ISO 21448 will be important for functional safety in autonomous driving.But compliance with established functional safety standards such as ISO 26262 will rema

46、in important.ISO 21434 Automotive Software SecurityISO 21434“Road vehicles cybersecurity engineering”is an automotive standard currently under development.It focuses on the cybersecurity risk in road vehicle electronic systems.The standard will cover all stages of a vehicles lifecycle from design th

47、rough to decommissioning by the application of cybersecurity engineering.This will apply to all electronic systems,components,and software in the vehicle,plus any external Perforce Software,Inc.All trademarks and registered trademarks are the property of their respective owners.(0220RB21)WHITE PAPER

48、8|Guide to Automotive Software DevelopmentWhats more,the standard will provide developers with a comprehensive approach to implementing security safeguards that spans the entire supplier chain.The intent behind the standard is to provide a structured process to ensure that cybersecurity consideratio

49、ns are incorporated into automotive products throughout their lifetime.The standard will require automotive manufacturers and suppliers to demonstrate due diligence in the implementation of cybersecurity engineering and that cybersecurity management is applied throughout the supply chain to support

50、it.It is intended that organizations will encourage a cybersecurity culture so that everything is designed with security considerations from the start.HOW TO COMPLY WITH ISO 21434ISO/SAE 21434 has specific requirements for software development including analysis to check for inherent weaknesses and

51、the overall consistency,correctness,and completeness with respect to cybersecurity requirements.Cybersecurity should be at the forefront of all design decisions including the selection of the programming language to be used for software development.There are several criteria to be considered when se

52、lecting a programming language,including:Secure design and coding techniques.Unambiguous syntax and semantic definitions.However,some of these criteria may not be sufficiently addressed in the selected language.Which is why there are several ways of addressing these language deficiencies,including:U

53、se of language subsets.Enforcement of strong typing.Use of defensive implementation techniques.It is recommended to use coding guidelines to address the deficiencies of the chosen language.C continues to be the most common language used in automotive software.MISRA C:2012 revision 1 and CERT C guide

54、lines are particularly recommended in ISO/SAE 21434 for any projects using the C language.Creating a language subset is the core of MISRA C:2012 and CERT C guidelines.MISRA C:2012 revision 1 states:“The MISRA C Guidelines define a subset of the C language”.Both guidelines achieve this by preventing

55、the use of functionality that may cause critical or unspecified behavior.Strong typing ensures that there is an understanding of the language data types and thus prevents certain classes of programming errors.Using coding guidelines,such as MISRA C:2012 and CERT C,that have strong typing ensures cor

56、rectness and consistency.Defensive implementation techniques allow software to continue to function even under unforeseen circumstances.It requires thought about“what might happen”.There needs to be,for example,consideration of possible tainted data and understanding of the order of evaluation of ar

57、ithmetic functions.Above all the code needs to be simple to understand.All defensive implementation techniques should start with the use of recognized coding guidelines.Both MISRA C:2012 Revision 1 and CERT C achieve this by identifying critical and unspecified language behavior and thus making the

58、resulting code more reliable,less prone to errors,and easier to maintain.The Essential Automotive Software Quality MetricsIn the Automotive Industry,software quality is paramount and software metrics are an important measure of that quality and are applicable to both function safety and functional s

59、ecurity standards Perforce Software,Inc.All trademarks and registered trademarks are the property of their respective owners.(0220RB21)WHITE PAPER9|Guide to Automotive Software DevelopmentHowever,no single metric can give a definitive measure of the quality of software and Automotive suppliers need

60、to agree with their OEM both the metrics they require and the acceptable limits of the values of those metrics.However,it is difficult to select the set of metrics that give the quality coverage required.HERSTELLER INITIATIVE SOFTWARE METRICSIn the Automotive industry,the obvious starting point for

61、the selection of metrics are those defined in Hersteller Initiative Software(HIS).HIS defines a common set of software metrics which permits a supplier to make statements about the quality of the software product and the software development process.In addition,an acceptable range of values of the d

62、efined metrics is specified.These metrics are separated into distinct categories:15 Metrics with limits that generally measure the complexity of the code.3 Metrics without limits that are simply measured values that must be documented.METRICS WITH LIMITSMetrics with limits indicate range of values s

63、howing the acceptable boundary limits.Violations of the boundary limits must be justified,and further action is required by the supplier.Examples of the metrics with limits specified in HIS:CYCLOMATIC COMPLEXITY“V(G)”Cyclomatic Complexity is the count of the number of linearly independent paths thro

64、ugh the source code.It can be used in two ways:1.To limit the complexity of code.2.To determine the number of test cases necessary to thoroughly test it.NUMBER OF GOTO STATEMENTS“GOTO”This metric is very simple,but it can easily be seen that the higher the number,the more paths through the code,whic

65、h means the more difficult the code is to test.NUMBER OF RETURN POINTS WITHIN A FUNCTION RETURN“Good practice dictates that the ideal value of this metric should be 1 as this improves the maintainability of the function(a function with no specific return is also acceptable).METRICS WITHOUT LIMITSAll

66、 the metrics in this section are similar:STMT(changed),STMT(new),STMT(deleted).These measure the number of statements in a piece of software that have changed,are new,or have been deleted between the previous and the current version of the software.These are used to calculate the stability index,whi

67、ch is part of Metrics with limits.HIS is purely concerned with the coding phase of the software life cycle.By analyzing these metrics,and ensuring that they are within the specified limits,the effort required in the following phases particularly testing will be reduced.METRICS FOR ISO 26262It is nec

68、essary for Automotive applications to certify to ISO 26262,and as a requirement to achieve this certification,a series of metrics must be gathered.The required level of metrics depends on the ASIL which determines the degree of risk.Higher ASILs require more thorough quality measures to control the

69、risk.Specific metrics are not required,but there are obvious well-known metrics that are Perforce Software,Inc.All trademarks and registered trademarks are the property of their respective owners.(0220RB21)WHITE PAPER10|Guide to Automotive Software DevelopmentFor example,ENFORCEMENT OF LOW COMPLEXIT

70、Y which is HIGHLY RECOMMENDED FOR ALL ASIL can be measured by lines of code(LOC)and Cyclomatic Complexity(as discussed in HIS metrics).Similarly,at an architectural level,RESTRICT SIZE AND COMPLEXITY OF SOFTWARE COMPONENTS HIGHLY RECOMMENDED FOR ALL ASIL can be measured by Halstead metrics which loo

71、k at the source code to identify areas that may be subject to defects by interpreting the code as a sequence of tokens.The metrics that count the tokens are:STM20 Counts ALL operands in the file STM21 Counts ALL operators in the fileOther measures can be calculated regarding program length and diffi

72、culty.For example:STM22 Number of statements in a software component STVAR Total number of Variables STTLN Total Pre-processed Source Lines There are,of course,other sections of ISO 26262 that require metrics,particularly methods for tests and deriving test cases.SOFTWARE QUALITY METRICS WILL ALWAYS

73、 MATTER FOR AUTOMOTIVE SOFTWARESoftware metrics are vital for assessing and maintaining quality in the Automotive Industry.There are metrics that are specific to the requirements of Automotive OEMs and suppliers,but the choice of metrics should not be limited by those necessary for certification pur

74、poses.The metrics selected should be applicable to the role of the viewer;the OEMs view is different to that of the supplier.Metrics should be selected to measure the progress to achieve specific goals,and the data gathered analyzed and used by the appropriate people.When this is done,they are inval

75、uable as a measure of progress and current software quality plus as an aid to improvement in the future.The Future of Automotive Software DevelopmentFuture development of Autonomous vehicles relies on AI and machine learning.One of the biggest challenges in this area is security.The starting point i

76、s a Secure Development ProcessesHere are three examples of key secure development processes:1.Good programming practices and thorough testing efforts are critical for eliminating security vulnerabilities.This can be achieved by using secure coding standards.2.Threat modeling and risk mitigation are

77、key to developing safe components.This can be achieved by doing a hazard and risk analysis.3.Control over the build/release environment is key to keeping hackers out and keeping the build secure.This can be achieved through access controls in your CI/CD environment.Part of the secure development pro

78、cess should be automation.Applying automation to design,verification,and validation processes makes development teams more efficient.Using a requirements management tool contributes to safer design of the software.Using a test case management tool can help you ensure high coverage of different scena

79、rios.This helps with software verification.Using a static analysis tool can help you simulate potential run-time scenarios.This helps with software Perforce Software,Inc.All trademarks and registered trademarks are the property of their respective owners.(0220RB21)About PerforcePerforce powers innov

80、ation at unrivaled scale.With a portfolio of scalable DevOps solutions,we help modern enterprises overcome complex product development challenges by improving productivity,visibility,and security throughout the product lifecycle.Our portfolio includes solutions for Agile planning&ALM,API management,

81、automated mobile&web testing,embeddable analytics,open source support,repository management,static&dynamic code analysis,version control,and more.With over 9,000 customers,Perforce is trusted by the worlds leading brands,including NVIDIA,Pixar,Scania,Ubisoft,and VMware.For more information,visit .WH

82、ITE PAPER11|Guide to Automotive Software DevelopmentHow Perforce Software Development Tools can Help Ensure Secure,Reliable,and Standards-Compliant Automotive SoftwareThe most effective way to ensure that your automotive software is secure,reliable,and standards-compliant is to use a suite of tools,

83、including a static code analyzer(like Helix QAC or Klocwork),a version control systems tool(like Helix Core),and an application lifecycle management tool(like Helix ALM).A static analyzer can be used to provide automatic enforcement of automotive coding guidelines such as MISRA and AUTOSAR.Yet,stati

84、c analysis can do so much more than this,such as:Automatically and consistently enforcing coding standards and detecting rule violations.Detecting compliance issues earlier in the SDLC.Accelerating code reviews.Reporting compliance over time and across product versions.See for yourself how Perforce

85、static code analyzers can help ensure that your automotive software is secure,reliable,and compliant.Request your free trial today.A version control systems tool,like Helix Core,supports your team and files as they grow.In addition,Helix Core supports build automation by:Providing a shared,centraliz

86、ed repository for commits.Maintaining a single source of truth for the build.Integrating with Jenkins and other build runners for better CI/CD projects.Automating workflows.Helix ALM provides end-to-end traceability by linking your requirements,test cases,and issues all inn one platform.Its configurable workflow easily adapts to the way you already work.This helps ensure that everyone on your team is able to seamlessly work together.TRY PERFORCE STATIC CODE ANALYZERSTRY HELIX CORETRY HELIX ALM