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SubjectRe: access_ok inside kernelspace
Actually, Ingo - there *is* one case where going through _syscallX() and
therefore int 0x80 from the kernel *is* the only way. This is when the
caller is a module. That is how I call sysfs() from BFS module.

So, if nobody objects to allowing modules to make system calls (as we
established the corruption this morning was just my bug - so behaviour is
valid), I will send this trivial patch to Linus (exporting errno):

--- ksyms.c.0 Tue Oct 19 12:44:53 1999
+++ ksyms.c Tue Oct 19 12:45:15 1999
@@ -40,6 +40,7 @@
#include <linux/poll.h>
#include <linux/mm.h>
#include <linux/capability.h>
+#include <linux/unistd.h>

#if defined(CONFIG_PROC_FS)
#include <linux/proc_fs.h>
@@ -79,6 +80,9 @@
#endif
EXPORT_SYMBOL(get_option);
EXPORT_SYMBOL(get_options);
+
+/* errno */
+EXPORT_SYMBOL(errno);

/* process memory management */
EXPORT_SYMBOL(do_mmap);

Regards,
------
Tigran A. Aivazian | http://www.sco.com
Escalations Research Group | tel: +44-(0)1923-813796
Santa Cruz Operation Ltd | http://www.ocston.org/~tigran
On Tue, 19 Oct 1999, Tigran Aivazian wrote:

> On Tue, 19 Oct 1999, Ingo Molnar wrote:
> > why this vendetta against using sys_ functions directly? We dont go
> > through a trap because in most cases that is unnecessery overhead. You are
> > not being logical i think.
>
> Yes, I understand that overhead is unnecessary. Which is why I now say -
> "why do we do _syscallX() from kernel at all? (other than when we *have*
> to)"
>
> And example I give is exec_modprobe() doing close(i) when it could just do
> sys_close(i).
>
> Regards,
> Tigran.
>
> PS. Thank you for your patient explanations!
>
>
>


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