sysproc.c和sysfile.c如何链接到xv6

Question

I am trying to add a set of system calls to support semaphore in xv6. I added a syssemaphore.c file(which will be instored with functions that will path the user arguments from the ustack using argptr, argint, etc..) and noticed that I cant find the h file which will link the functions I will write. basicly I want to add files like sysproc.c and sysfile.c. is it possible?

Answer 1

Adding a new system call to XV6 meaning altering the entire system call mechanism flow, from user space invoking system call interrupt while setting the system call id number in eax register, through syscall function which runs the right system call handler, and finally to the system call implementation (which includes a sys_something function to retrieve user parameters and validate them).

If I understand your question correctly, you're new file, syssemaphore.c, includes the sys_something functions that you wish to call from syscall in syscall.c file.

The syscall function is the only function that should invoke your new sys_something wrappers. therefore, it will be sufficient to add those functions prototypes (as extern function) above the syscalls array in syscall.c file, which will then allow you to add your new functions to the syscalls array.

See additional information at How to pass a value into system call XV6