Table of Contents
1. Introduction................................................................................................................5
2. The Players .................................................................................................................6
2.1. User Context .....................................................................................................6
2.2. Hardware Interrupts (Hard IRQs) .....................................................................7
2.3. Software Interrupt Context: Bottom Halves, Tasklets, softirqs ........................7
3. Some Basic Rules........................................................................................................9
4. ioctls: Not writing a new system call ......................................................................10
5. Recipes for Deadlock ...............................................................................................12
6. Common Routines....................................................................................................13
6.1. printk() include/linux/kernel.h.......................................................13
6.2. copy_[to/from]_user() / get_user() / put_user()
include/asm/uaccess.h..........................................................................13
6.3. kmalloc()/kfree() include/linux/slab.h.........................................14
6.4. current include/asm/current.h...........................................................15
6.5. local_irq_save()/local_irq_restore() include/asm/system.h15
6.6. local_bh_disable()/local_bh_enable() include/asm/softirq.h
16
6.7. smp_processor_id()/cpu_[number/logical]_map()
include/asm/smp.h...................................................................................16
6.8. __init/__exit/__initdata include/linux/init.h.......................................16
6.9. __initcall()/module_init() include/linux/init.h .....................17
6.10. module_exit() include/linux/init.h ..............................................17
6.11. MOD_INC_USE_COUNT/MOD_DEC_USE_COUNT include/linux/module.h
18
7. Wait Queues include/linux/wait.h .................................................................20
7.1. Declaring.........................................................................................................20
7.2. Queuing...........................................................................................................20
7.3. Waking Up Queued Tasks...............................................................................20
8. Atomic Operations...................................................................................................22
9. Symbols .....................................................................................................................23
3
9.1. EXPORT_SYMBOL() include/linux/module.h........................................23
9.2. EXPORT_SYMTAB ............................................................................................23
10. Routines and Conventions.....................................................................................24
10.1. Double-linked lists include/linux/list.h............................................24
10.2. Return Conventions.......................................................................................24
10.3. Breaking Compilation...................................................................................24
10.4. Initializing structure members ......................................................................24
10.5. GNU Extensions ...........................................................................................25
10.6. C++ ...............................................................................................................26
10.7. #if ..................................................................................................................26
11. Putting Your Stuff in the Kernel...........................................................................27
12. Kernel Cantrips......................................................................................................29
13. Thanks.....................................................................................................................31
