Messages in this thread | | | Date | Mon, 21 May 2007 09:28:01 +0200 | From | Stefan Richter <> | Subject | Re: [PATCH] Fix/add raw1394 CONFIG_COMPAT code |
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I wrote: > Arnd Bergmann wrote: >>>> Note that this data structure only needs conversion on x86_64 and ia64, but >>>> not on powerpc and other 64 bit architectures that align __u64 also in >>>> 32 bit mode. ... > maybe we should change > > /* argument to RAW1394_IOC_GET_CYCLE_TIMER ioctl */ > struct raw1394_cycle_timer { ... > __u32 cycle_timer; ... > __u64 local_time; > }; > > to > > /* argument to RAW1394_IOC_GET_CYCLE_TIMER ioctl */ > struct raw1394_cycle_timer { ... > __u64 cycle_timer; ... > __u64 local_time; > }; > > before a libraw1394 with get-cycle-timer support is released.
On the other hand, we could handle it in the compat code alone and leave the rest as-is.
/* PPC32 aligns this at 64bit, IA32 packs it */ struct raw1394_cycle_timer32 { __u32 cycle_timer; __u64 local_time; } #if defined(CONFIG_X86_64) || defined(CONFIG_IA64) __attribute__((packed)) #endif ;
Eventually, Arnd's suggestion
> I would suggest you introduce a new __compat_u64 type as > > typedef __u64 __compat_u64 __attribute__((aligned(4))); > > in include/asm-{x86_64,ia64}/compat.h and as > > typdef __u64 __compat_u64; > > in the other architectures. Other people have hit the same problem > before and found varying workarounds, but I think we should just > do it correctly now.
should be put into practice though. -- Stefan Richter -=====-=-=== -=-= =-=-= http://arcgraph.de/sr/ - 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/
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