On Wed, Nov 18, 2009 at 08:04:18AM +0100, Heiko Carstens wrote:
> Please note that other architectures (I think at least arm and powerpc) put
> 64 bit values into even/odd register pairs and add padding if the first free
> available register is an odd one. So any of the following interfaces should
> work for all architectures:
>
> long sys_fanotify_mark(int fanotify_fd, unsigned int flags,
> int fd, const char __user *pathname,
> u32 mask_high, u32 mask_low);
>
> long sys_fanotify_mark(int fanotify_fd, unsigned int flags,
> u64 mask,
> int fd, const char __user *pathname);
>
> long sys_fanotify_mark(u64 mask,
> int fanotify_fd, unsigned int flags,
> int fd, const char __user *pathname);
Correct - but the splitting is unnecessary pain for some platforms like
64-bit userland on 64-bit MIPS where the 64-bit argument would be passed
in a single register so I have preference for the 2nd or 3rd suggestion.
The 1st prototype has the advantage of avoiding the need for a compat
wrapper which otherwise would look like:
long compat_sys_fanotify_mark(int fanotify_fd, unsigned int flags,
u32 a2, u32 a3,
int fd, const char __user *pathname);
{
/* assuming 2nd suggested prototype from above */
return sys_fanotify_mark(fd, flags,
merge64(a2, a3),
fd, pathname);
}
I'd prefer to see the compat code carrying the burden.
Ralf
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