1author: Sean Ruyle (srruyle@us.ibm.com) 2 3RUNTIME: 4To run the test case simply enter the user_space directory, type make 5to compile the program, and run ./test_mod in this case, or whatver 6you have named your program. However, the test kernel module must be 7loaded before the test case can work. If the module is not loaded you 8will receive an error when attempting to open the module. 9 10Enter the kernel_space directory, and again type make to compile the 11module. After successful compilation use the load script to load the 12module into the system (./load_tmod.sh). The reason for the script 13instead of just using insmod to load the module is to ensure that 14there is a correct node in /dev, by parsing /proc/devices to get the 15right major number. 16 17Check that the module has been loaded by using the lsmod command. 18You should see ouput similar to this: 19 20ausag:~ # lsmod 21Module Size Used by 22tmod 3812 0 23gcov_prof 8292 0 24uhci_hcd 51812 0 25 26 27To unload the module use the rmmod command. A module cannot be 28unloaded if it is still in use by the system or a program. 29 30 31 32 33USER SPACE: 34Ive tried to abstract user space as much as possible so that if 35a new test does not need any additional setup of parameters 36before the ioctl call, ki_generic can be used by passing in 37the file_descriptor and the ioctl flag corresponding to the 38current test. 39 40Examples have been provided for correct usage of passing in 41structures to the ioctl call if they are needed for a given 42test. These are fuond at the bottom of tmod_ki.c file. 43 44If a test does call for a structure to be passed in to 45kernel space or a structure to be returned you will need to 46setup the tif pointer. Use the examples I just mentioned 47and it should be easy. The ioctl call is setup so that it 48will check if the values passed in need a copy_from_user 49or a copy_to_user before moving on. The tif pointer 50allows the kernel space ioctl function to handle all 51calls in a similar function without depending on the test 52that is to be run, in regards to copy_from_user and 53copy_to_user. 54 55 56 57 58KERNEL SPACE: 59I strongly suggest that when creating a Makefile for your 60test modules you use the one provided here, and just change 61the name of the .o file. Little differences can throw a 62compiler off even if you dont see a problem. 63 64The test functions and the ioctl call, as well as init and 65exit functions are located in the tmod.c file. Most of it 66should be streamlined so that all you need to do to add a 67new test function is add an ioctl flag in tmod.h, a function 68prototype, a new case in the ioctl switch, and the actual 69function itself. 70 71Two header files are needed in kernel space so that we may 72seperate what can be used in user space programs from 73what can only be used in kernel space. I put my #defines 74and ioctl flags in tmod.h, along with the tif structure. 75This is because all of these will need to be used by both 76the user space program as well as the kernel module. 77 78Any extern definitions from the kernel or structures that 79will have pointers in them that will differ in user space, 80should go in another header file. I used str_mod.h for this, 81and for example in my pci testcase, I need a struct pci_dev * 82for most of my tests, along with several other pointers. 83This structure will allow you to hold the pointers from one 84test to another without having to use copy_to_user to 85return the pointers to user space program. 86 87 88 89 90 91 92On naming: 93For this example I just called everything tmod (short for test_mod), 94so if you are using these files as a base for your testcases, make 95sure that you change tmod and other such inferences, so that it 96will be easier to tell in the kernel which module is performing 97which action. 98 99 100 101 102 103 104Hope this helps. Send me an email if you have any problems 105Thanks and gigem, 106Sean Ruyle 107 108srruyle@us.ibm.com 109 110 111 112 113 114 115 116 117 118