Re: sources of linux 'system call'
Joshua Roys <[email protected]> Thu, 13 Sep 2007 14:47:37 -0400
| Newsgroups | org.kernel.vger.linux-assembly |
|---|---|
| Message-ID | <[email protected]> |
Lukas wrote: > Thank You for answer ... i'll read this sources ... > but actualy i want to know what instructions processor > recive after int. My goal is to understand better GDT, > IDT, LDT in Linux, i want to know what's going on when > i call for example 125 system call (sys_mprotect) > whitch allow me change acces rights to given memory > area. Theory i know ( almost everything is writen in > Intel guides ) but i need practice. By the way if > smoebody knoe how to change acces rigts to memory > without system calls, please help :) > > regards > Lukas Hello, Take a look at (for i386): arch/i386/kernel/entry.S Then find a line like: ENTRY(system_call) That gets set in the IDT in: arch/i386/kernel/traps.c, near the end of function trap_init() Specifically: set_system_gate(SYSCALL_VECTOR, &systen_call), where SYSCALL_VECTOR is defined to be 0x80 And: include/asm-i386/desc.h has some items that may be of interest to you. Good luck, Joshua Roys