Hi Kiran, The switch to the kernel stack takes place automatically when the syscall is made. It is not done by software, but by the hardware. When the hardware detects a change in privilege level its changes esp to the value corresponding to ring 0 .. I think the esp values for different privilege levels are stored in the TSS segment of the process. Cheers, Bijoy. ----- Original Message ----- From: Kiran Kumar <immidi_kiran@yahoo.com> Date: Saturday, July 3, 2004 11:05 am Subject: switching from user stack to kernel stack > Hi, > When a process makes a system call, in the kernel > space a separate stack would have to be used. (the one > associated with the task_struct of the process). This > would mean that the %esp would have to be modified in > the system call handler routine. I dont seem to find > out where this is done. ENTRY(system_call) in entry.S > does not seem to be doing this. I would like to know > where the code to switch between user and kernel mode > stacks is. > > > ===== > Regards, > Kiran Kumar Immidi > > > > __________________________________ > Do you Yahoo!? > Yahoo! Mail - 50x more storage than other providers! > http://promotions.yahoo.com/new_mail > > -- > Kernelnewbies: Help each other learn about the Linux kernel. > Archive: http://mail.nl.linux.org/kernelnewbies/ > FAQ: http://kernelnewbies.org/faq/ > > -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ FAQ: http://kernelnewbies.org/faq/
