[RFC PATCH] ARM: add workaround for ambiguous C99 stdint.h types

[Nicolas Pitre]

On Tue, 13 Aug 2013, Ard Biesheuvel wrote:

> Kinda-acked-by Dave Martin, anyone else care to comment?
> 

Acked-by: Nicolas Pitre <nico at linaro.org>

> On 9 August 2013 09:36, Ard Biesheuvel <ard.biesheuvel at linaro.org> wrote:
> > The C99 types uintXX_t that are usually defined in 'stdint.h' are not as
> > unambiguous on ARM as you would expect. For the types below, there is a
> > difference on ARM between GCC built for bare metal ARM, GCC built for glibc
> > and the kernel itself, which results in build errors if you try to build with
> > -ffreestanding and include 'stdint.h' (such as when you include 'arm_neon.h'
> > in order to use NEON intrinsics)
> >
> > As the typedefs for these types in 'stdint.h' are based on builtin defines
> > supplied by GCC, we can tweak these to align with the kernel's idea of those
> > types, so 'linux/types.h' and 'stdint.h' can be safely included from the same
> > source file (provided that -ffreestanding is used).
> >
> >                    int32_t         uint32_t               uintptr_t
> > bare metal GCC     long            unsigned long          unsigned long
> > glibc GCC          int             unsigned int           unsigned int
> > kernel             int             unsigned int           unsigned long
> >
> > Signed-off-by: Ard Biesheuvel <ard.biesheuvel at linaro.org>
> > ---
> >
> > Hi all,
> >
> > This is another, less obtrusive way of handling the problem for which I
> > previously sent an RFC patch 'types.h: use GCC supplied typedefs if appropriate'
> > In this case, only source files that in fact include stdint.h and are being
> > built for ARM should be affected.
> >
> > Regards,
> > --
> > Ard.
> >
> >
> >  arch/arm/include/asm/types.h | 40 ++++++++++++++++++++++++++++++++++++++++
> >  1 file changed, 40 insertions(+)
> >  create mode 100644 arch/arm/include/asm/types.h
> >
> > diff --git a/arch/arm/include/asm/types.h b/arch/arm/include/asm/types.h
> > new file mode 100644
> > index 0000000..976ac31
> > --- /dev/null
> > +++ b/arch/arm/include/asm/types.h
> > @@ -0,0 +1,40 @@
> > +#ifndef _ASM_TYPES_H
> > +#define _ASM_TYPES_H
> > +
> > +#include <asm-generic/int-ll64.h>
> > +
> > +/*
> > + * The C99 types uintXX_t that are usually defined in 'stdint.h' are not as
> > + * unambiguous on ARM as you would expect. For the types below, there is a
> > + * difference on ARM between GCC built for bare metal ARM, GCC built for glibc
> > + * and the kernel itself, which results in build errors if you try to build with
> > + * -ffreestanding and include 'stdint.h' (such as when you include 'arm_neon.h'
> > + * in order to use NEON intrinsics)
> > + *
> > + * As the typedefs for these types in 'stdint.h' are based on builtin defines
> > + * supplied by GCC, we can tweak these to align with the kernel's idea of those
> > + * types, so 'linux/types.h' and 'stdint.h' can be safely included from the same
> > + * source file (provided that -ffreestanding is used).
> > + *
> > + *                    int32_t         uint32_t               uintptr_t
> > + * bare metal GCC     long            unsigned long          unsigned long
> > + * glibc GCC          int             unsigned int           unsigned int
> > + * kernel             int             unsigned int           unsigned long
> > + */
> > +
> > +#ifdef __INT32__TYPE__
> > +#undef __INT32__TYPE__
> > +#define __INT32__TYPE__                int
> > +#endif
> > +
> > +#ifdef __UINT32__TYPE__
> > +#undef __UINT32__TYPE__
> > +#define __UINT32__TYPE__       unsigned int
> > +#endif
> > +
> > +#ifdef __UINTPTR_TYPE__
> > +#undef __UINTPTR_TYPE__
> > +#define __UINTPTR_TYPE__       unsigned long
> > +#endif
> > +
> > +#endif /* _ASM_TYPES_H */
> > --
> > 1.8.1.2
> >
>