svn commit: r313006 - in head: sys/conf sys/libkern sys/libkern/x86 sys/sys tests/sys/kern

[Bruce Evans]

On Tue, 31 Jan 2017, Conrad E. Meyer wrote:

> Log:
>  calculate_crc32c: Add SSE4.2 implementation on x86

This breaks building with gcc-4.2.1, and depends on using non-kernel clang
headers for clang.

> Modified: head/sys/conf/files.amd64
> ==============================================================================
> --- head/sys/conf/files.amd64	Tue Jan 31 01:55:29 2017	(r313005)
> +++ head/sys/conf/files.amd64	Tue Jan 31 03:26:32 2017	(r313006)
> @@ -593,6 +593,11 @@ compat/ndis/subr_pe.c		optional	ndisapi
> compat/ndis/subr_usbd.c		optional	ndisapi pci
> compat/ndis/winx64_wrap.S	optional	ndisapi pci
> #
> +crc32_sse42.o			standard				\

I don't want it, but it is standard.

> +	dependency	"$S/libkern/x86/crc32_sse42.c"			\
> +	compile-with	"${CC} -c ${CFLAGS:N-nostdinc} ${WERROR} ${PROF} -msse4 ${.IMPSRC}" \

-msse4 is not supported by gcc-4.2.1,

Removing nostdinc pollutes the build with host headers, and the one needed
might not be installed, and it doesn't exist for gcc-4.2.1.

Similarly for i386.

> Modified: head/sys/libkern/crc32.c
> ==============================================================================
> --- head/sys/libkern/crc32.c	Tue Jan 31 01:55:29 2017	(r313005)
> +++ head/sys/libkern/crc32.c	Tue Jan 31 03:26:32 2017	(r313006)
> @@ -46,8 +46,14 @@
> __FBSDID("$FreeBSD$");
>
> #include <sys/param.h>
> +#include <sys/libkern.h>

Style bug.  libkern.h is part if systm.h.

> #include <sys/systm.h>

Ordering bug.  systm.h is a prerequisite for all kernel headers except
param.h, since it defines macros which might be used by other headers.

> Added: head/sys/libkern/x86/crc32_sse42.c
> ==============================================================================
> --- /dev/null	00:00:00 1970	(empty, because file is newly added)
> +++ head/sys/libkern/x86/crc32_sse42.c	Tue Jan 31 03:26:32 2017	(r313006)
> @@ -0,0 +1,288 @@
> ...
> +#ifdef USERSPACE_TESTING
> +#include <stdint.h>
> +#else
> +#include <sys/param.h>
> +#include <sys/kernel.h>
> +#include <sys/libkern.h>
> +#include <sys/systm.h>
> +#endif

Style and ordering bugs, as above.

> +
> +#include <nmmintrin.h>

This header is outside of the kernel source tree.  It is not even in
/usr/include, but clang finds it in:

crc32_sse42.o:
   /usr/bin/../lib/clang/3.9.0/include/nmmintrin.h \
   /usr/bin/../lib/clang/3.9.0/include/smmintrin.h \
   /usr/bin/../lib/clang/3.9.0/include/tmmintrin.h \
   /usr/bin/../lib/clang/3.9.0/include/pmmintrin.h \
   /usr/bin/../lib/clang/3.9.0/include/emmintrin.h \
   /usr/bin/../lib/clang/3.9.0/include/xmmintrin.h \
   /usr/bin/../lib/clang/3.9.0/include/mmintrin.h \
   /usr/bin/../lib/clang/3.9.0/include/f16cintrin.h \
   /usr/bin/../lib/clang/3.9.0/include/popcntintrin.h

nmmintrin.h doesn't exist for gcc-4.2.1.  gcc-4.2.1 has some of the other
intrin.h files, but they aren't installed in FreeBSD-9, and of course they
don't support newer SSE.

Inline asm is much less unportable than intrinsics.  kib used the correct
method of .byte's in asms to avoid depending on assembler support for newer
instructions.  .byte is still used for clflush on amd64 and i386.  It
used to be used for invpcid on amd64.  I can't find where it is or was
used for xsave stuff.

Bruce