Re: [Dri-devel] 32/64bit issues in ioctl struct passing

[Philip B. <ph...@bo...>]

On Tue, Mar 04, 2003 at 11:59:50AM -0600, Andy Isaacson wrote:
> On Tue, Mar 04, 2003 at 09:41:54AM -0800, Philip Brown wrote:
> > On Tue, Mar 04, 2003 at 01:27:28PM +0000, Alan Cox wrote:
> > > On all 64bit bit platforms I have met unsigned long is a 64bit quantity.
> > > In fact I can't think of a single exception
> > 
> > Well then, obviously, you dont use solaris :-)
> 
> He uses Solaris and compiles for 64-bit mode, rather than the 32-bit
> mode you're compiling for.
> ...
> 
> The 64-bit kernel is perfectly capable of running 32-bit binaries, and
> that's precisely what you're doing.

Yes. And that's exactly what DRI users will do. So right there is a 
64/32 bit problem.

In drm.h, to take just one example.

typedef struct drm_map {
        unsigned long offset; /* Requested physical address (0 for SAREA)*/
        unsigned long size; /* Requested physical size (bytes) */
        drm_map_type_t type; /* Type of memory to map */
        drm_map_flags_t flags; /* Flags */
        void *handle; /* User-space: "Handle" to pass to mmap */
                                 /* Kernel-space: kernel-virtual address */
        int mtrr; /* MTRR slot used */
                                 /* Private data */
} drm_map_t;

So kernel will be compiled with offset=64bits, user mode will be compiled
with offset=32bits... boom.

All numeric fields passed through the ioctls, should have fixed,
identifiable sizes.