When Your Code Crosses Into the Kernel
You call read(). Your CPU shifts into another gear. Privilege level drops from 3 to 0. Your instruction pointer jumps to an address you can’t even see from user space. This happens millions of times per second on production servers, and most developers have no idea what’s actually going on.
Here’s what they don’t tell you: the syscall instruction is one of the most carefully orchestrated handoffs in computing. Get it wrong, and you corrupt kernel memory. Get it slow, and your entire system grinds to a halt.
https://github.com/sysdr/howtech/tree/main/systems/syscall
https://www.youtube.com/watch?v=Gj06pAZY91U
[https://howt…
When Your Code Crosses Into the Kernel
You call read(). Your CPU shifts into another gear. Privilege level drops from 3 to 0. Your instruction pointer jumps to an address you can’t even see from user space. This happens millions of times per second on production servers, and most developers have no idea what’s actually going on.
Here’s what they don’t tell you: the syscall instruction is one of the most carefully orchestrated handoffs in computing. Get it wrong, and you corrupt kernel memory. Get it slow, and your entire system grinds to a halt.
https://github.com/sysdr/howtech/tree/main/systems/syscall