author: Sean Ruyle (srruyle@us.ibm.com) RUNTIME: To run the test case simply enter the user_space directory, type make to compile the program, and run ./test_mod in this case, or whatver you have named your program. However, the test kernel module must be loaded before the test case can work. If the module is not loaded you will recieve an error when attempting to open the module. Enter the kernel_space directory, and again type make to compile the module. After successful compilation use the load script to load the module into the system (./load_tmod.sh). The reason for the script instead of just using insmod to load the module is to ensure that there is a correct node in /dev, by parsing /proc/devices to get the right major number. Check that the module has been loaded by using the lsmod command. You should see ouput similar to this: ausag:~ # lsmod Module Size Used by tmod 3812 0 gcov_prof 8292 0 uhci_hcd 51812 0 To unload the module use the rmmod command. A module cannot be unloaded if it is still in use by the system or a program. USER SPACE: Ive tried to abstract user space as much as possible so that if a new test does not need any additional setup of parameters before the ioctl call, ki_generic can be used by passing in the file_descriptor and the ioctl flag corresponding to the current test. Examples have been provided for correct usage of passing in structures to the ioctl call if they are needed for a given test. These are fuond at the bottom of tmod_ki.c file. If a test does call for a structure to be passed in to kernel space or a structure to be returned you will need to setup the tif pointer. Use the examples I just mentioned and it should be easy. The ioctl call is setup so that it will check if the values passed in need a copy_from_user or a copy_to_user before moving on. The tif pointer allows the kernel space ioctl function to handle all calls in a similar function without depending on the test that is to be run, in regards to copy_from_user and copy_to_user. KERNEL SPACE: I strongly suggest that when creating a Makefile for your test modules you use the one provided here, and just change the name of the .o file. Little differences can throw a compiler off even if you dont see a problem. The test functions and the ioctl call, as well as init and exit functions are located in the tmod.c file. Most of it should be streamlined so that all you need to do to add a new test function is add an ioctl flag in tmod.h, a function prototype, a new case in the ioctl switch, and the actual function itself. Two header files are needed in kernel space so that we may seperate what can be used in user space programs from what can only be used in kernel space. I put my #defines and ioctl flags in tmod.h, along with the tif structure. This is because all of these will need to be used by both the user space program as well as the kernel module. Any extern definitions from the kernel or structures that will have pointers in them that will differ in user space, should go in another header file. I used str_mod.h for this, and for example in my pci testcase, I need a struct pci_dev * for most of my tests, along with several other pointers. This structure will allow you to hold the pointers from one test to another without having to use copy_to_user to return the pointers to user space program. On naming: For this example I just called everything tmod (short for test_mod), so if you are using these files as a base for your testcases, make sure that you change tmod and other such inferences, so that it will be easier to tell in the kernel which module is performing which action. Hope this helps. Send me an email if you have any problems Thanks and gigem, Sean Ruyle srruyle@us.ibm.com