Modern Age: The start_kernel( ) Function
by Marco Cesati, Daniel P. Bovet
Understanding the Linux Kernel, Second Edition
- Understanding the Linux Kernel, 2nd Edition
- Preface
- 1. Introduction
- Linux Versus Other Unix-Like Kernels
- Hardware Dependency
- Linux Versions
- Basic Operating System Concepts
- An Overview of the Unix Filesystem
- An Overview of Unix Kernels
- 2. Memory Addressing
- 3. Processes
- 4. Interrupts and Exceptions
- 5. Kernel Synchronization
- Kernel Control Paths
- When Synchronization Is Not Necessary
- Synchronization Primitives
- Synchronizing Accesses to Kernel Data Structures
- Choosing Among Spin Locks, Semaphores, and Interrupt Disabling
- Protecting a data structure accessed by exceptions
- Protecting a data structure accessed by interrupts
- Protecting a data structure accessed by deferrable functions
- Protecting a data structure accessed by exceptions and interrupts
- Protecting a data structure accessed by exceptions and deferrable functions
- Protecting a data structure accessed by interrupts and deferrable functions
- Protecting a data structure accessed by exceptions, interrupts, and deferrable functions
- Choosing Among Spin Locks, Semaphores, and Interrupt Disabling
- Examples of Race Condition Prevention
- 6. Timing Measurements
- 7. Memory Management
- Page Frame Management
- Memory Area Management
- The Slab Allocator
- Cache Descriptor
- Slab Descriptor
- General and Specific Caches
- Interfacing the Slab Allocator with the Buddy System
- Allocating a Slab to a Cache
- Releasing a Slab from a Cache
- Object Descriptor
- Aligning Objects in Memory
- Slab Coloring
- Local Array of Objects in Multiprocessor Systems
- Allocating an Object in a Cache
- Releasing an Object from a Cache
- General Purpose Objects
- Noncontiguous Memory Area Management
- 8. Process Address Space
- The Process’s Address Space
- The Memory Descriptor
- Memory Regions
- Page Fault Exception Handler
- Creating and Deleting a Process Address Space
- Managing the Heap
- 9. System Calls
- 10. Signals
- 11. Process Scheduling
- 12. The Virtual Filesystem
- 13. Managing I/O Devices
- I/O Architecture
- Device Files
- Device Drivers
- Block Device Drivers
- Character Device Drivers
- 14. Disk Caches
- 15. Accessing Files
- 16. Swapping: Methods for Freeing Memory
- What Is Swapping?
- Swap Area
- The Swap Cache
- Transferring Swap Pages
- Swapping Out Pages
- Swapping in Pages
- Reclaiming Page Frame
- 17. The Ext2 and Ext3 Filesystems
- 18. Networking
- 19. Process Communication
- 20. Program Execution
- A. System Startup
- B. Modules
- C. Source Code Structure
- 21. Bibliography
- Index
- Colophon
The start_kernel( ) function completes the
initialization of the Linux kernel. Nearly every kernel component is
initialized by this function; we mention just a few of them:
The Page Tables are initialized by invoking the
paging_init( )function (see Section 2.5.5).The page descriptors are initialized by the
kmem_init( ),free_area_init( ), andmem_init( )functions (see Section 7.1.4).The final initialization of the IDT is performed by invoking
trap_init( )(see Section 4.5) andinit_IRQ( )(see Section 4.6.1.2).The slab allocator is initialized by the
kmem_cache_init( )andkmem_cache_sizes_init( )functions (see Section 7.2.4).The system date and time are initialized by the
time_init( )function (see Section 6.1.1).The kernel thread for process 1 is created by invoking the
kernel_thread( )function. In turn, this kernel thread creates the other kernel threads and executes the/sbin/initprogram, as described in Section 3.4.2 in Chapter 3.
Besides the “Linux version 2.4.18 . . .
" message, which is displayed right after the
beginning of start_kernel( ), many other messages
are displayed in this last phase, both by the
init functions and by the kernel threads. At the
end, the familiar login prompt appears on the console (or in the
graphical screen, if the X Window System is launched at startup),
telling the user that the Linux kernel is up and running.
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