Implementation Details

Contents:

• Bottom-Half Interrupt Handlers
  • RTOS Interrupts
  • Extending interrupt processing
  • High Priority Work Queue
  • Setting Up Bottom Half Interrupt Processing
• Cancellation Points
  • Cancellation Types
  • Enter and Leave Cancelation Point
  • pthread_cancel()
  • select()
  • Application Interfaces
  • Task Deletion
  • Design Issues
  • Issue 619 Discussion
• chip.h
  • The purpose of the two chip.h files in each arm chip
• Context Switches
  • Two Types of Context Switches
  • Synchronous Context Switches
  • System Calls
• Critical Sections
  • Types and Effects of Critical Sections
  • Single CPU Critical Sections
  • SMP Critical Sections
  • The Critical Section Monitor
  • IRQ Monitor and Worst Case Response Time
• Device Drivers
  • Standard Device Drivers
  • Bus Drivers
  • Test Drivers
  • User Space Drivers
  • Communication Devices
  • I/O Expander
• Device Nodes
  • Linux Device Nodes
  • NuttX Device Nodes
  • Usage Differences
  • boardctl()
• OS Drivers Design
  • Character and Block Drivers
  • MTD Drivers
  • Monolithic Drivers
  • Upper Half and Lower Half Drivers
• File Descriptors
  • Drivers within Drivers
  • Drivers File Descriptors
  • Detaching Open Files
  • Detached File Helpers
  • The SYLOG Device: A Case Study
  • Other Examples
  • Socket Descriptors
• Hardfaults
  • ARMv7
• Per-Thread Interrupt Controls
• ioctl
  • Not a Typewriter
  • NuttX
  • Linux Explanation
• Kernel Modules vs Shared Libraries
  • Kernel Modules
  • Shared Libraries
  • FLAT Build
  • PROTECTED Build
  • Better FLAT and PROTECTED Mode Shared Libraries
  • KERNEL Build
• Kernel Threads vs. Pthreads
  • Why Can’t Kernel Threads Have pthreads?
  • The FLAT build
  • Roadmap
• Make Build System
  • Verbosity
  • Build Process
  • Win.mk
  • Unix.mk
  • Config.mk
  • FlatLibs.mk
  • ProtectedLibs.mk
  • KernelLibs.mk
  • Directories.mk
  • LibTargets.mk
• Memory Configurations
  • Flat, Embedded Build
  • On-Demand Paging
  • Protected Build
  • Address Environments
  • Kernel Build
  • The Roadmap Toward Processes
  • Terminology
• Naming of Architecture, MCU, and Board Interfaces
  • Common Microcontroller Interfaces
  • Microcontroller-Specific Interfaces
  • Architecture-Specific Interfaces
  • Common Board Interfaces
  • Specific Interfaces
• Naming of OS Internal Functions
  • Legacy smooshed-together names
  • System-Object-Verb Naming
  • System-Verb-Object Naming
  • Unit Suffixes
  • Implicit get
  • Other Naming
  • Conclusion
• NuttX Initialization Sequence
  • Overview
  • Case example: STM32 F4
  • Phase A - Power-On Reset Initialization
  • Phase B - NuttX RTOS Initialization
  • Phase C - Application Initialization
• NuttX Tasking
  • An RTOS as a library
  • Kernel Threads
  • The Scheduler
  • State Transition Diagram
  • Scheduling Policies
  • Task IDs
  • NuttX Tasks
  • The Pseudo File System and Device Drivers
  • Inheritance of the Task Environment and I/O Redirection
  • Tasks vs. Pthreads
  • Process IDs / Task IDs / Pthread IDs
• Oneshot Timers and CPU Load Measurement
  • Issues with CPU Load Measurement
  • External Clock
  • Using a Oneshot Timer to Drive CPU Load Measurement
  • Entropy
• Power Management
  • Power Management (PM) Subsystem
  • Dynamic Clocking
• Effects of Disabling Interrupts or Pre-Emption on Response Latency
  • Rate Monotonic Scheduling
• Linux Processes vs NuttX Tasks
  • NuttX Build Types
  • Initialization of Global Variables
  • Global Variables and Multiple Task Copies
  • Memory Clean-Up
• Short Time Delays
  • System Timer Interrupt
  • Timer Resolution
  • usleep()
  • Timer Hook
• Signal Handlers
  • Sending Thread
  • Receiving Thread
• The NuttX Simulation
  • How the Simulator is Built
  • The nuttx.rel Blob
  • The $(HOSTOBJ) Blob
  • Accessing Host Devices Using FIFOs?
  • Toward a General Design
  • What is Wrong With That?
  • Simulated Interrupts
  • Supported Devices
• SMP (Symmetric MultiProcessing)
  • Definition
  • Development Status
  • Enabling SMP
  • Design Requirements
  • Data Structures
  • System Startup
  • Scheduler Interactions
  • Interrupt Handling
  • System Calls
  • Critical Sections
  • Spinlocks
  • Disabling Pre-emption
  • Disabling Interrupts
  • Pre-Emption Controls and Critical Sections
  • Signal Handlers
  • Thread Affinity
• SysLog
  • Standard SysLog Interfaces
  • Debug Interfaces
  • SYSLOG Channels
  • SYSLOG Channel Options
  • SYSLOG (Input) Character Device
  • Using SYSLOG for Debug
• Tasks vs. Threads
  • What is the difference between a thread and a task in Nuttx?
  • When would I want to use a task? When would I want to use a thread?
  • How do signals work in a task group with many pthreads?
  • How do atexit() and on_exit() work with task groups?
  • How does waitpid() work with task groups?
  • What are privileged threads? How are threads handled differently when NuttX is built as a Kernel
• Tickless OS
  • Default System Timer
  • Tickless OS Advantages
  • Platform Support
  • Configuration Options
  • System Interfaces
  • Issues
• TLS: Thread Local Storage
  • Historical Background
  • errno
  • Task-Specific Globals in the FLAT and PROTECTED builds
  • Re-Entrant getopt()
  • Unaligned TLS
  • Push-Up vs. Push-Down Stacks
  • TLS interfaces
  • pthread-specific data
  • Accessing the errno from kernel space
  • Wild Ideas
  • Code References
• USB (Universal Serial Bus)
  • NAKing USB OUT/IN Tokens