Messages in this thread | | | Subject | Re: [PATCH] ARM: fix vdsomunge depends on glibc specific byteswap.h | From | "H. Nikolaus Schaller" <> | Date | Wed, 30 Sep 2015 18:13:23 +0200 |
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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.
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).
Thanks, Nikolaus Schaller
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