Syscall or sysenter on 32 bits Linux?

Question

Since MS‑DOS, I know system invocation using interrupts. In old papers, I saw reference to int 80h to invoke system functions on Linux. Since a rather long time now

Answer 1

After some web searching, I landed to this other topic on StackOverflow: Linux invoke a system call via sysenter tutorial. It says the recommended way to invoke the system, is neither using int 80h nor syscall nor sysenter, but linux-gate.so.

Still remains the question about the crash and core‑dump. My guess is finally that although either syscall or sysenter instructions are available as a CPU instruction, may be the Linux kernel just does not set‑up properly this “entry point” when it decide it's not really useful on a given hardware platform.

Seems on 32 bits platform, sysenter or syscall may be available, while it's always available, only on 64 bits platform.

Although I feel this answer my question, I still welcome more material, like an authoritative reference for my above guess.

-- update --

At least, I could find this which confirm the above. That's still not an authoritative reference but seems trustable enough I believe.

What is linux-gate.so.1?, says:

The preferred way of invoking a system call is determined by the kernel at boot time, and evidently this box uses sysenter.

Also, from another source, a sample FASM assembly source (needs some translations if you use NASM), to call a system function via linux-gate.so: Finding linux-gate.so.1 in Assembly .