Messages in this thread | | | Subject | compat_ioctl question | From | Paul Fulghum <> | Date | Thu, 26 Apr 2007 15:51:57 -0500 |
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I need to add ioctl translations for my driver to allow 32 bit access on 64 bit systems.
After digging through the kernel code there seems to be 3 methods of doing this:
1. define compat_ioctl() file operation for device and implement translation code in individual driver 2. add COMPATIBLE_IOCTL entry to include/linux/compat_ioctl.h to mark an ioctl code as the same in any environment 3. add HANDLE_IOCTL entry to fs/compat_ioctl.c with translation code implemented in the same file
There is no way to implement #1 for a tty driver without modifying the kernel tty code to allow registration of a compat_ioctl() handler.
#3 would put a lot of driver specific stuff in a common kernel file. This method also seems to break if there is an ioctl code collision.
All of these methods involve changes to code outside of my driver.
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Before I spend a lot of time on this I need to know what the officially sanctioned method is. I haven't found any definitive documentation and a review of mailing list archives does not suggest a prevailing opinion.
Does anyone have pointers on which way would be most likely to be accepted as a patch?
Thanks, Paul
-- Paul Fulghum Microgate Systems, Ltd
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