Messages in this thread | | | Date | Wed, 30 Sep 2015 18:17:52 +0200 | Subject | Re: [PATCH] ARM: fix vdsomunge depends on glibc specific byteswap.h | From | Ard Biesheuvel <> |
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On 30 September 2015 at 18:13, H. Nikolaus Schaller <hns@goldelico.com> wrote: > > Am 30.09.2015 um 18:02 schrieb Ard Biesheuvel <ard.biesheuvel@linaro.org>: > >> On 30 September 2015 at 17:56, H. Nikolaus Schaller <hns@goldelico.com> wrote: >>> If the host toolchain is not glibc based then the arm kernel build >>> fails with >>> >>> HOSTCC arch/arm/vdso/vdsomunge >>> arch/arm/vdso/vdsomunge.c:48:22: fatal error: byteswap.h: No such file or directory >>> >>> Observed with omap2plus_defconfig and compile on Mac OS X with arm ELF >>> cross-compiler. >>> >>> Reason: byteswap.h is a glibc only header. >>> >>> Changed to detect the host and include the right file as described at: >>> >>> https://bugs.freedesktop.org/show_bug.cgi?id=8882 >>> >>> Tested to compile on Mac OS X 10.9.5 host. >>> >>> Signed-off-by: H. Nikolaus Schaller <hns@goldelico.com> >>> --- >>> arch/arm/vdso/vdsomunge.c | 18 ++++++++++++++++++ >>> 1 file changed, 18 insertions(+) >>> >>> diff --git a/arch/arm/vdso/vdsomunge.c b/arch/arm/vdso/vdsomunge.c >>> index aedec81..5364cea 100644 >>> --- a/arch/arm/vdso/vdsomunge.c >>> +++ b/arch/arm/vdso/vdsomunge.c >>> @@ -45,7 +45,25 @@ >>> * it does. >>> */ >>> >>> +#if defined(__linux__) >>> #include <byteswap.h> >>> +#elif defined(__OpenBSD__) >>> +#include <sys/endian.h> >>> +#define bswap_16 __swap16 >>> +#define bswap_32 __swap32 >>> +#define bswap_64 __swap64 >>> +#elif defined(__APPLE__) >>> +#include <libkern/OSByteOrder.h> >>> +#define bswap_16 OSSwapInt16 >>> +#define bswap_32 OSSwapInt32 >>> +#define bswap_64 OSSwapInt64 >>> +#else >>> +#include <sys/endian.h> >>> +#define bswap_16 bswap16 >>> +#define bswap_32 bswap32 >>> +#define bswap_64 bswap64 >>> +#endif >>> + >> >> Have you tried this? >> >> #define bswap_16 __builtin_bswap16 >> #define bswap_32 __builtin_bswap32 >> #define bswap_64 __builtin_bswap64 >> >> https://gcc.gnu.org/onlinedocs/gcc/Other-Builtins.html > > OS X host uses llvm and I am not sure if these builtins are > always available. >
I am pretty sure recent clang supports these as well. Could you please try it?
> So it replaces an include file dependency by a compiler > built-in dependency. IMHO my approach is more general > and should cover a broader range of compile hosts. > > This is a tool compiled by HOSTCC to be run on the build > host - so I think we can't assume to have a gcc host compiler > (while for the CC cross-compiler we can). >
If my suggestion works, we'll support host side GCC and clang without decorating the source code with lots of #ifdefs for OSes few people care about. That would be an improvement imo
Thanks, Ard.
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