On 18/09/12 21:48, H Hartley Sweeten wrote:
On Tuesday, September 18, 2012 1:15 PM, H Hartley Sweeten wrote:
On Tuesday, September 18, 2012 12:13 PM, Dan Carpenter wrote:
This introduces some new Sparse warnings in the compat code.
Ugh.. I thought my .config was building this driver since it was in
my build log.
I think the Makefile should be fixed so the #ifdef CONFIG_COMPAT
can be removed from comedi_compat32.c. Oh well, different issue.
CHECK drivers/staging/comedi/comedi_compat32.c
drivers/staging/comedi/comedi_compat32.c:212:16: warning: cast removes address space of expression
drivers/staging/comedi/comedi_compat32.c:212:16: warning: cast removes address space of expression
drivers/staging/comedi/comedi_compat32.c:212:16: warning: cast removes address space of expression
drivers/staging/comedi/comedi_compat32.c:212:16: warning: cast removes address space of expression
CC [M] drivers/staging/comedi/comedi_compat32.o
210 err |= __put_user(temp.uint, &cmd->stop_arg);
211 err |= __get_user(temp.uptr, &cmd32->chanlist);
212 err |= __put_user(compat_ptr(temp.uptr), &cmd->chanlist);
213 err |= __get_user(temp.uint, &cmd32->chanlist_len);
214 err |= __put_user(temp.uint, &cmd->chanlist_len);
215 err |= __get_user(temp.uptr, &cmd32->data);
216 err |= __put_user(compat_ptr(temp.uptr), &cmd->data);
217 err |= __get_user(temp.uint, &cmd32->data_len);
I'm not sure how to cast away the warnings...
Would it work to just "get" the value as an unsigned long and the "put"
it back as an unsigned long?
If I read this code correctly there might be another issue.
This only moves the first level values between the 32-bit user view of
the struct to the 64-bit kernel view of the struct. But what about the
values that chainlist actually points to?
Those values remain in userspace, but will now be pointed to by a 64-bit
userspace pointer. The normal 64-bit unlocked_ioctl handler will deal
with them.
Doing a new build now with CONFIG_COMPAT enabled. I'll take a
look at it then.
Well, I thought I had CONFIG_COMPAT enabled...
What's the trick to enable that config option?
You're building it for x86-64, right? You need to select "IA32
Emulation" (CONFIG_IA32_EMULATION) and/or "x32 ABI for 64-bit mode
(EXPERIMENTAL)" (CONFIG_X86_X32). I've never tested the latter option.
--
-=( Ian Abbott @ MEV Ltd. E-mail: <abbotti@xxxxxxxxx> )=-
-=( Tel: +44 (0)161 477 1898 FAX: +44 (0)161 718 3587 )=-
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