On Sat, May 23, 2009 at 1:02 PM, SandeepKsinha <sandeepksinha@gmail.com> wrote:
quoted text > IMO, binutils members can answer this better.
> copying binutils list....
>
> On Sat, May 23, 2009 at 12:06 AM, seshikanth varma
> <seshikanthvarma@gmail.com> wrote:
>> Hi
>> I googled out but i could not find these things:
>>> .section .fixup
>>> .previous
>>> .align 4
>> Can u please help me in finding the meaning of these things? Any document
>> which gives elaborate explanation would be really helpful for me for
>> future reference, I have seen some more things in linux source code like
>> __extable ....
>>
>>
>>
>> On Sun, May 17, 2009 at 4:16 PM, SandeepKsinha <sandeepksinha@gmail.com>
>> wrote:
>>>
>>> On Sun, May 17, 2009 at 3:18 PM, seshikanth varma
>>> <seshikanthvarma@gmail.com> wrote:
>>> > Hi All,
>>> > I am trying to understand the implementation of copy_from_user() and
>>> > copy_to_user() implementation in linux. I know the basics of asm format.
>>> > But
>>> > i don't know what is
>>> > .section .fixup
>>> > .previous
>>> > .align 4
>>> > Can u please point me to a detailed documentation of asm details
>>> > involving
>>> > the above?
>>>
>>> Google for "inline assembly" and "assembly in C".
>>>
>>> > Thanks,
>>> > Seshikanth
>>> >
>>> > 320 * Tell gcc we read from memory instead of writing: this is because
>>> > 321 * we do not write to any memory gcc knows about, so there are no
>>> > 322 * aliasing issues.
>>> > 323 */
>>> > 324#define __put_user_asm(x, addr, err, itype, rtype, ltype, errret)
>>> > \
>>> > 325 __asm__ __volatile__(
>>> > \
>>> > 326 "1: mov"itype" %"rtype"1,%2\n"
>>> > \
>>> > 327 "2:\n"
>>> > \
>>> > 328 ".section .fixup,\"ax\"\n"
>>> > \
>>> > 329 "3: movl %3,%0\n"
>>> > \
>>> > 330 " jmp 2b\n"
>>> > \
>>> > 331 ".previous\n"
>>> > \
>>> > 332 ".section __ex_table,\"a\"\n"
>>> > \
>>> > 333 " .align 4\n"
>>> > \
>>> > 334 " .long 1b,3b\n"
>>> > \
>>> > 335 ".previous"
>>> > \
>>> > 336 : "=r"(err)
>>> > \
>>> > 337 : ltype (x), "m"(__m(addr)), "i"(errret), "0"(err))
>>> > 338
>>> > 339
>>> >
>>> > --
>>> > Regards,
>>> > Seshikanth
>>> >
>>>
>>>
>>>
>>> --
>>> Regards,
>>> Sandeep.
>>>
>>>
>>>
>>>
>>>
>>>
>>> “To learn is to change. Education is a process that changes the learner.”
>>
>>
>>
>> --
>> Regards,
>> Seshikanth
>>
>
>
>
> --
> Regards,
> Sandeep.
>
>
>
>
>
>
> “To learn is to change. Education is a process that changes the learner.”
>
--
Regards,
Sandeep.
“To learn is to change. Education is a process that changes the learner.”
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