Mastering Assembly Programming

.init.text

This section contains the code required for successful initialization of an LKM. In our case, as we are not adding any functionality to the module, it could simply return, but as we need an indication of our LKM having loaded successfully, we will implement a tiny procedure, which will print a string into the system log:

section '.init.text' executable module_init:   push  rdi       ; We are going to use this register      mov   rdi, str1 ; Load RDI with the address of the string                   ; we want to print to system log (we will                   ; add it to the data section in a few moments)   xor   eax, eax   call  printk    ; Write the string to the system log   xor   eax, eax  ; Prepare return value   pop   rdi       ; Restore the RDI register   ret

Rather simple, isn't it? We just print the ...