Bijoy (bijoyjth@gwu.edu) wrote: > > > You are probably confusing the user-space and the kernel-space side of > > the thing. On the user-side, the wrapper takes arguments from the stack > > and loads them to the registers. And calls the trap. Now the kernel > > parts comes to play. It does some setup and calls the sys_* function. > > But the arguments are still in registers. So the asmlinkage tells the > > compiler, that the function will have the args in registers and not on > > the stack, as would be expected for C function. > > Isnt it the other way around .... when the sys_* function is called .. the > arguments are on the stack .... the syscall handler saves the register > arguments (SAVE_ALL) and then invokes the actual syscall .... asmlinkage > means that the arguments are on the stack and not in registers .... plz > correct me if i am wrong. Hi, As I can understand about syscall and asmlinkage: >From user space, syscall's arguments are stored in registers, and number of syscall are in eax. x80 int are launched, and arch/i386/entry.S come to ENTRY(system_call) and arguments are pushed on stack. sys_ functions are called from address stored in sys_call_table. Then the sys_ function is executed and asmlinkage say to not optimized the arguments and to take arguments from stack. If I make a mistake, I will happy you give me the right way. Regards, -- Amicalement Christophe * GNU/Linux & UNIX developer and network administrator * Membre RotomaLUG (http://www.rotomalug.org) * Registered User #271267 * Email: c.lucas@ifrance.com * Web Site: http://odie.mcom.fr/~clucas/ -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ FAQ: http://kernelnewbies.org/faq/
