what does this do ?

what does this do ?

[horseriver]

hi:

  In kernel code . some function is defined  by  __attribute__((__section__(".initcall" level ".init")))

  what does this do ?


thanks!

what does this do ?

[horseriver]

On Sun, Jan 13, 2013 at 09:27:45PM -0800, Dave Hylands wrote:
> Hi,
> 
> On Sun, Jan 13, 2013 at 11:29 AM, horseriver <horserivers@gmail.com> wrote:
> >
> > hi:
> >
> >   In kernel code . some function is defined  by
>  __attribute__((__section__(".initcall" level ".init")))
> >
> >   what does this do ?
> 
> It puts the address of the function in a linker section named
> .initcallX.init where X is replaced by the level.

   why ".initcall" and level do not connect  together with ## ?
   As I know , precompiler use ## to connect two strings


  Thanks!   
> 
> These functions are called in order to initialize various subsystems and
> drivers during kernel bootup.
> 
> --
> Dave Hylands
> Shuswap, BC, Canada
> http://www.davehylands.com

what does this do ?

[horseriver]

On Sun, Jan 13, 2013 at 09:27:45PM -0800, Dave Hylands wrote:
> Hi,
> 
> On Sun, Jan 13, 2013 at 11:29 AM, horseriver <horserivers@gmail.com> wrote:
> >
> > hi:
> >
> >   In kernel code . some function is defined  by
>  __attribute__((__section__(".initcall" level ".init")))
> >
> >   what does this do ?
> 
> It puts the address of the function in a linker section named
> .initcallX.init where X is replaced by the level.
> 
> These functions are called in order to initialize various subsystems and
> drivers during kernel bootup.

  Thanks!

  Another question:
  
  __attribute__((regparm(3)))    ;  what does this do ?



 
> --
> Dave Hylands
> Shuswap, BC, Canada
> http://www.davehylands.com

what does this do ?

[Dave Hylands]

Hi,

On Sun, Jan 13, 2013 at 11:29 AM, horseriver <horserivers@gmail.com> wrote:
>
> hi:
>
>   In kernel code . some function is defined  by
 __attribute__((__section__(".initcall" level ".init")))
>
>   what does this do ?

It puts the address of the function in a linker section named
.initcallX.init where X is replaced by the level.

These functions are called in order to initialize various subsystems and
drivers during kernel bootup.

--
Dave Hylands
Shuswap, BC, Canada
http://www.davehylands.com
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what does this do ?

[horseriver]

On Mon, Jan 14, 2013 at 07:20:46AM -0800, Ramesh.P wrote:
> Hi,
> 
> 
> On Sun, Jan 13, 2013 at 8:50 PM, horseriver <horserivers@gmail.com> wrote:
> 
> > On Sun, Jan 13, 2013 at 09:27:45PM -0800, Dave Hylands wrote:
> > > Hi,
> > >
> > > On Sun, Jan 13, 2013 at 11:29 AM, horseriver <horserivers@gmail.com>
> > wrote:
> > > >
> > > > hi:
> > > >
> > > >   In kernel code . some function is defined  by
> > >  __attribute__((__section__(".initcall" level ".init")))
> > > >
> > > >   what does this do ?
> > >
> > > It puts the address of the function in a linker section named
> > > .initcallX.init where X is replaced by the level.
> > >
> > > These functions are called in order to initialize various subsystems and
> > > drivers during kernel bootup.
> >
> >   Thanks!
> >
> >   Another question:
> >
> >   __attribute__((regparm(3)))    ;  what does this do ?
> >

  Thank You!

   what the use of doing like this ?  why  tell gcc  to  pass param like this ?

 
> >
> It causes the compiler to pass the argument (3 in this case) to be passed
> in registers (like EAX, ECX and EDX) instead of stack.
> 
> Thanks,
> Ramesh
> 
> 
> >
> >
> >
> > > --
> > > Dave Hylands
> > > Shuswap, BC, Canada
> > > http://www.davehylands.com
> >
> > _______________________________________________
> > Kernelnewbies mailing list
> > Kernelnewbies at kernelnewbies.org
> > http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
> >

what does this do ?

[horseriver]

On Mon, Jan 14, 2013 at 02:44:11PM +0000, Anuz Pratap Singh Tomar wrote:
> On Mon, Jan 14, 2013 at 4:50 AM, horseriver <horserivers@gmail.com> wrote:
> 
> > On Sun, Jan 13, 2013 at 09:27:45PM -0800, Dave Hylands wrote:
> > > Hi,
> > >
> > > On Sun, Jan 13, 2013 at 11:29 AM, horseriver <horserivers@gmail.com>
> > wrote:
> > > >
> > > > hi:
> > > >
> > > >   In kernel code . some function is defined  by
> > >  __attribute__((__section__(".initcall" level ".init")))
> > > >
> > > >   what does this do ?
> > >
> > > It puts the address of the function in a linker section named
> > > .initcallX.init where X is replaced by the level.
> > >
> > > These functions are called in order to initialize various subsystems and
> > > drivers during kernel bootup.
> >
> >   Thanks!
> >
> >   Another question:
> >
> >   __attribute__((regparm(3)))    ;  what does this do ?
> >
> >
> >
> > A simple google search should have answered this
> http://ohse.de/uwe/articles/gcc-attributes.html
> 
> Synopsis
> 
> regparm (NUMBER) Found in versions: 2.7-3.4 Description:
> 
>      Functions that take a variable number of
>      arguments will continue to be passed all of their arguments on the
>      stack.
> 
>      what does this mean?
> 
> 
> 
> > > --
> > > Dave Hylands
> > > Shuswap, BC, Canada
> > > http://www.davehylands.com
> >
> > _______________________________________________
> > Kernelnewbies mailing list
> > Kernelnewbies at kernelnewbies.org
> > http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
> >
> 
> 
> 
> -- 
> Thank you
> Warm Regards
> Anuz

what does this do ?

[Dave Hylands]

Hi,

On Sun, Jan 13, 2013 at 12:09 PM, horseriver <horserivers@gmail.com> wrote:
>
> On Sun, Jan 13, 2013 at 09:27:45PM -0800, Dave Hylands wrote:
> > Hi,
> >
> > On Sun, Jan 13, 2013 at 11:29 AM, horseriver <horserivers@gmail.com>
wrote:
> > >
> > > hi:
> > >
> > >   In kernel code . some function is defined  by
> >  __attribute__((__section__(".initcall" level ".init")))
> > >
> > >   what does this do ?
> >
> > It puts the address of the function in a linker section named
> > .initcallX.init where X is replaced by the level.
>
>    why ".initcall" and level do not connect  together with ## ?
>    As I know , precompiler use ## to connect two strings


That's not quite true. ## is the token pasting operator and is for pasting
together pieces of a token to create a larger token.
http://gcc.gnu.org/onlinedocs/cpp/Concatenation.html

If you have the tokens someVar_  and somethingElse you could token paste
them together to make someVar_somethingElse

The # operator is a for stringizing,which converts non-strings into strings.
http://gcc.gnu.org/onlinedocs/cpp/Stringification.html#Stringification

In C and C++ you can "paste" strings together by just putting them one
after the  other.

const char *x = "This is a long string.";

is 100% identical to

const char *x = "This"     " is a long "    "string.";
http://en.wikipedia.org/wiki/C_syntax#String_literal_concatenation

--
Dave Hylands
Shuswap, BC, Canada
http://www.davehylands.com
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what does this do ?

[Anuz Pratap Singh Tomar]

On Mon, Jan 14, 2013 at 4:50 AM, horseriver <horserivers@gmail.com> wrote:

> On Sun, Jan 13, 2013 at 09:27:45PM -0800, Dave Hylands wrote:
> > Hi,
> >
> > On Sun, Jan 13, 2013 at 11:29 AM, horseriver <horserivers@gmail.com>
> wrote:
> > >
> > > hi:
> > >
> > >   In kernel code . some function is defined  by
> >  __attribute__((__section__(".initcall" level ".init")))
> > >
> > >   what does this do ?
> >
> > It puts the address of the function in a linker section named
> > .initcallX.init where X is replaced by the level.
> >
> > These functions are called in order to initialize various subsystems and
> > drivers during kernel bootup.
>
>   Thanks!
>
>   Another question:
>
>   __attribute__((regparm(3)))    ;  what does this do ?
>
>
>
> A simple google search should have answered this
http://ohse.de/uwe/articles/gcc-attributes.html

Synopsis

regparm (NUMBER) Found in versions: 2.7-3.4 Description:

     On the Intel 386, the `regparm' attribute causes the compiler to
     pass up to NUMBER integer arguments in registers EAX, EDX, and ECX
     instead of on the stack.  Functions that take a variable number of
     arguments will continue to be passed all of their arguments on the
     stack.

     Beware that on some ELF systems this attribute is unsuitable for
     global functions in shared libraries with lazy binding (which is
     the default).  Lazy binding will send the first call via resolving
     code in the loader, which might assume EAX, EDX and ECX can be
     clobbered, as per the standard calling conventions.  Solaris 8 is
     affected by this.  GNU systems with GLIBC 2.1 or higher, and
     FreeBSD, are believed to be safe since the loaders there save all
     registers.  (Lazy binding can be disabled with the linker or the
     loader if desired, to avoid the problem.)



> > --
> > Dave Hylands
> > Shuswap, BC, Canada
> > http://www.davehylands.com
>
> _______________________________________________
> Kernelnewbies mailing list
> Kernelnewbies at kernelnewbies.org
> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>



-- 
Thank you
Warm Regards
Anuz
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what does this do ?

[Ramesh.P]

Hi,


On Sun, Jan 13, 2013 at 8:50 PM, horseriver <horserivers@gmail.com> wrote:

> On Sun, Jan 13, 2013 at 09:27:45PM -0800, Dave Hylands wrote:
> > Hi,
> >
> > On Sun, Jan 13, 2013 at 11:29 AM, horseriver <horserivers@gmail.com>
> wrote:
> > >
> > > hi:
> > >
> > >   In kernel code . some function is defined  by
> >  __attribute__((__section__(".initcall" level ".init")))
> > >
> > >   what does this do ?
> >
> > It puts the address of the function in a linker section named
> > .initcallX.init where X is replaced by the level.
> >
> > These functions are called in order to initialize various subsystems and
> > drivers during kernel bootup.
>
>   Thanks!
>
>   Another question:
>
>   __attribute__((regparm(3)))    ;  what does this do ?
>
>
It causes the compiler to pass the argument (3 in this case) to be passed
in registers (like EAX, ECX and EDX) instead of stack.

Thanks,
Ramesh


>
>
>
> > --
> > Dave Hylands
> > Shuswap, BC, Canada
> > http://www.davehylands.com
>
> _______________________________________________
> Kernelnewbies mailing list
> Kernelnewbies at kernelnewbies.org
> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>
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what does this do ?

[Anuz Pratap Singh Tomar]

On Mon, Jan 14, 2013 at 6:02 AM, horseriver <horserivers@gmail.com> wrote:

> On Mon, Jan 14, 2013 at 02:44:11PM +0000, Anuz Pratap Singh Tomar wrote:
> > On Mon, Jan 14, 2013 at 4:50 AM, horseriver <horserivers@gmail.com>
> wrote:
> >
> > > On Sun, Jan 13, 2013 at 09:27:45PM -0800, Dave Hylands wrote:
> > > > Hi,
> > > >
> > > > On Sun, Jan 13, 2013 at 11:29 AM, horseriver <horserivers@gmail.com>
> > > wrote:
> > > > >
> > > > > hi:
> > > > >
> > > > >   In kernel code . some function is defined  by
> > > >  __attribute__((__section__(".initcall" level ".init")))
> > > > >
> > > > >   what does this do ?
> > > >
> > > > It puts the address of the function in a linker section named
> > > > .initcallX.init where X is replaced by the level.
> > > >
> > > > These functions are called in order to initialize various subsystems
> and
> > > > drivers during kernel bootup.
> > >
> > >   Thanks!
> > >
> > >   Another question:
> > >
> > >   __attribute__((regparm(3)))    ;  what does this do ?
> > >
> > >
> > >
> > > A simple google search should have answered this
> > http://ohse.de/uwe/articles/gcc-attributes.html
> >
> > Synopsis
> >
> > regparm (NUMBER) Found in versions: 2.7-3.4 Description:
> >
> >      Functions that take a variable number of
> >      arguments will continue to be passed all of their arguments on the
> >      stack.
> >
> >      what does this mean?
> >
>

May be you should really read more.
I would suggest reading some i386 assembly.

Thank you
Warm Regards
Anuz
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