sysenter vs int 80h

[MarisO]

hi

I'd like to use sysenter instead of int 80h but I couldn't find any information on how to do it.  Can you help me ?

[Bryant Keller]

Here is a decent document I found through Galileo:

http://www.cs.auckland.ac.nz/compsci215s2c/lectures/robert/lecture15.pdf

[Keith Kanios]

Is this with/for a 32-bit or 64-bit system?

[MarisO]

32 bit

[MarisO]

Here is a decent document I found through Galileo:

thanks  that's what I need :-)

[MarisO]

Still I don't get how to use SYSENTER. Can I use it in my code (in 32 bit Linux)?
I tried to use SYSENTER and the programm segfaults.   I guess it is because CPU doesn't know where to return.  Linux needs to set EDX and ECX before returning (via SYSEXIT), but what does it put in these registers ?

I can't set EDX and ECX myself because it would conflict with , for example, write file syscall.

Code: [Select]

mov eax,4           
mov ebx,1           
mov ecx,msgAddress
mov edx,msgLen
int 80h   ;  SYSENTER here segfaults


[Keith Kanios]

Read Sysenter Based System Call Mechanism in Linux 2.6.