possible problem with generic asm/types.h

possible problem with generic asm/types.h

[Mark Salter]

While building some stuff for aarch64, I ran into a conflict between
the kernel's definition of __s64 and glibc's definition of int64_t.
The package I was building (fuse) does this:

  #include <stdint.h>
  #define __s64 int64_t

The kernel typedefs __s64 in asm/types.h and due to ordering of includes
in the fuse package sources, the kernel __s64 gets used at some points
while the fuse __s64 gets used in others. This leads to a build failure
on aarch64 because glibc typedefs int64_t as a long while kernel uses
long long for __s64. Both are 64bits but it creates a type conflict in
some of the fuse code. But this same fuse code builds on other arches so
I looked a further and found what I think is a problem with the kernel's
asm-generic/types.h file which has:

    /*
     * int-ll64 is used practically everywhere now,
     * so use it as a reasonable default.
     */
    #include <asm-generic/int-ll64.h>

Shouldn't this be:

    #include <asm/bitsperlong.h>
    #if __BITS_PER_LONG == 64
    #include <asm-generic/int-l64.h>
    #else
    #include <asm-generic/int-ll64.h>
    #endif

--Mark

Re: possible problem with generic asm/types.h

[Geert Uytterhoeven]

On Sat, May 25, 2013 at 5:14 PM, Mark Salter <msalter@redhat.com> wrote:
>     /*
>      * int-ll64 is used practically everywhere now,

This comment is obsolete, it's used everywhere now.

>      * so use it as a reasonable default.
>      */
>     #include <asm-generic/int-ll64.h>
>
> Shouldn't this be:
>
>     #include <asm/bitsperlong.h>
>     #if __BITS_PER_LONG == 64
>     #include <asm-generic/int-l64.h>
>     #else
>     #include <asm-generic/int-ll64.h>
>     #endif

No. Inside the kernel, all 64-bit platforms use int-ll64.h.

For backwards compatibility, alpha, ia64, mips, and powerpc (unless
__SANE_USERSPACE_TYPES__ is defined) still use int-l64.h in userspace.

So it seems your glibc ues the old convention. Any chance you can still
switch?

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

Re: possible problem with generic asm/types.h

[Mark Salter]

On Sat, 2013-05-25 at 18:01 +0200, Geert Uytterhoeven wrote:
> On Sat, May 25, 2013 at 5:14 PM, Mark Salter <msalter@redhat.com> wrote:
> >     /*
> >      * int-ll64 is used practically everywhere now,
> 
> This comment is obsolete, it's used everywhere now.
> 
> >      * so use it as a reasonable default.
> >      */
> >     #include <asm-generic/int-ll64.h>
> >
> > Shouldn't this be:
> >
> >     #include <asm/bitsperlong.h>
> >     #if __BITS_PER_LONG == 64
> >     #include <asm-generic/int-l64.h>
> >     #else
> >     #include <asm-generic/int-ll64.h>
> >     #endif
> 
> No. Inside the kernel, all 64-bit platforms use int-ll64.h.

Except for alpha and ia64...

> 
> For backwards compatibility, alpha, ia64, mips, and powerpc (unless
> __SANE_USERSPACE_TYPES__ is defined) still use int-l64.h in userspace.
> 
> So it seems your glibc ues the old convention. Any chance you can still
> switch?

Not glibc, which provides the same stdint.h for all arches. The problem
is the namespace pollution caused by the app defining __s64 to be
glibc's int64_t. I assume that aarch64 kernel headers pull in the kernel
definition of __s64 for some reason where other kernel arches do not. So
it is just by luck that fuse builds on the other arches. I think I'll
take it up with the fuse maintainers...

--Mark

Re: possible problem with generic asm/types.h

[Geert Uytterhoeven]

On Sat, May 25, 2013 at 6:37 PM, Mark Salter <msalter@redhat.com> wrote:
>> No. Inside the kernel, all 64-bit platforms use int-ll64.h.
>
> Except for alpha and ia64...

Nope:

$ git grep int-l arch/{alpha,ia64}/include/asm/types.h
arch/alpha/include/asm/types.h:#include <asm-generic/int-ll64.h>
arch/ia64/include/asm/types.h:#include <asm-generic/int-ll64.h>
$

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

Re: possible problem with generic asm/types.h

[Mark Salter]

On Sat, 2013-05-25 at 18:39 +0200, Geert Uytterhoeven wrote:
> On Sat, May 25, 2013 at 6:37 PM, Mark Salter <msalter@redhat.com> wrote:
> >> No. Inside the kernel, all 64-bit platforms use int-ll64.h.
> >
> > Except for alpha and ia64...
> 
> Nope:
> 
> $ git grep int-l arch/{alpha,ia64}/include/asm/types.h
> arch/alpha/include/asm/types.h:#include <asm-generic/int-ll64.h>
> arch/ia64/include/asm/types.h:#include <asm-generic/int-ll64.h>
> $

Hmm.

$ git grep int-l arch/{alpha,ia64}/include/uapi/asm/types.h
arch/alpha/include/uapi/asm/types.h:#include <asm-generic/int-l64.h>
arch/ia64/include/uapi/asm/types.h:#include <asm-generic/int-l64.h>

Re: possible problem with generic asm/types.h

[Geert Uytterhoeven]

On Sat, May 25, 2013 at 6:43 PM, Mark Salter <msalter@redhat.com> wrote:
> On Sat, 2013-05-25 at 18:39 +0200, Geert Uytterhoeven wrote:
>> On Sat, May 25, 2013 at 6:37 PM, Mark Salter <msalter@redhat.com> wrote:
>> >> No. Inside the kernel, all 64-bit platforms use int-ll64.h.
          ^^^^^^^^^^^^^^^^
>> >
>> > Except for alpha and ia64...
>>
>> Nope:
>>
>> $ git grep int-l arch/{alpha,ia64}/include/asm/types.h
>> arch/alpha/include/asm/types.h:#include <asm-generic/int-ll64.h>
>> arch/ia64/include/asm/types.h:#include <asm-generic/int-ll64.h>
>> $
>
> Hmm.
>
> $ git grep int-l arch/{alpha,ia64}/include/uapi/asm/types.h
> arch/alpha/include/uapi/asm/types.h:#include <asm-generic/int-l64.h>
> arch/ia64/include/uapi/asm/types.h:#include <asm-generic/int-l64.h>

As I wrote before:
> For backwards compatibility, alpha, ia64, mips, and powerpc (unless
> __SANE_USERSPACE_TYPES__ is defined) still use int-l64.h in userspace.
                                                           ^^^^^^^^^^^^

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

Re: possible problem with generic asm/types.h

[Arnd Bergmann]

On Saturday 25 May 2013, Mark Salter wrote:
> 
> While building some stuff for aarch64, I ran into a conflict between
> the kernel's definition of __s64 and glibc's definition of int64_t.
> The package I was building (fuse) does this:
> 
>   #include <stdint.h>
>   #define __s64 int64_t

It's an old bug in fuse. The header that ships with the kernel
should work fine, just update your user space package.

	Arnd