Messages in this thread | ![/](/images/icornerl.gif) | | Date | Thu, 20 Feb 2003 23:45:32 +0100 | From | Andrea Arcangeli <> | Subject | Re: Syscall from Kernel Space |
| |
On Thu, Feb 20, 2003 at 05:17:30PM -0500, Jeff Garzik wrote: > On Thu, Feb 20, 2003 at 11:10:27PM +0100, Andrea Arcangeli wrote: > > On Thu, Feb 20, 2003 at 12:40:43PM -0500, Jeff Garzik wrote: > > > On Thu, Feb 20, 2003 at 11:04:37PM +0530, Prasad wrote: > > > > Is there a way using which i could invoke a syscall in the kernel > > > > space? The syscall is to be run disguised as another process. The actual > > > > > > Call sys_<syscall>. Look at the kernel code for examples. > > > > > > Note that typically you don't want to do this... and you _really_ don't > > > want to do this if the syscall is not one of the common file I/O > > > syscalls (read/write/open/close, etc.) > > > > you never want to do this, the only point of a syscall is to enter > > kernel, if you're just in kernel you're wasting time in calling the > > syscall (not to tell about the new non soft interrupt based syscall > > instructions, btw this is also why I rejected the int 0x81 thing on > > x86-64 for 64bit syscalls) > > He is talking about directly calling the function behind the syscall, > not actually executing a syscall itself.
this is not what I understood from your previous discussion also given you suggest not to do that when he can call sys_read/sys_write instead because they're just exported etc.. I just wanted to add a better "never".
> syscalls should be made from userspace, not the kernel.
This is what I tried to say.
Andrea - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| ![\](/images/icornerr.gif) |