Re: Suggestion: LKM should be able to add system call for itself
- From: Arjan van de Ven <arjan@xxxxxxxxxxxxx>
- Date: Mon, 7 Jul 2008 07:29:45 -0700
On Mon, 7 Jul 2008 08:12:00 -0400
"Jinkai Gao" <mickeygjk@xxxxxxxxx> wrote:
On Mon, Jul 7, 2008 at 3:01 AM, Arjan van de Ven
<arjan@xxxxxxxxxxxxx> wrote:
On Mon, 7 Jul 2008 01:09:30 -0400
"Jinkai Gao" <mickeygjk@xxxxxxxxx> wrote:
Above is to demonstrate that LKM is extension to kernel, and the
system calls should be able to extend as long as the kernel is
extending. So The LKM should be able to define its own user
interface by adding new system call for itself.
Since we promise a stable ABI to userspace, this is a bit of a
problem.
But... look today, we already have various system calls implemented
by modules. (example: sys_nfsservctl)
but to make it fully dynamic? Not a good idea... nobody would be
able to program to it.
Why? Using the interface we provide to add and delete system call (the
module can only unregister the system calls registered by itself), all
the existing system calls will be the same. It is just you can have
more system calls then you need, That shouldn't be a problem.
but when the kernel later adds new ones.. overlap.
Really.. it's not hard to do this. Look at nfs etc. You CAN do this,
just you need to reserve your system call number officially (and create
a manpage for it describing what it does)... and then it doesn't really
matter if it's module or vmlinux who provides it. Again.. nfs has
solved this.
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- Suggestion: LKM should be able to add system call for itself
- From: Jinkai Gao
- Re: Suggestion: LKM should be able to add system call for itself
- From: Arjan van de Ven
- Re: Suggestion: LKM should be able to add system call for itself
- From: Jinkai Gao
- Suggestion: LKM should be able to add system call for itself
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