| Message ID | 1474892258-178638-1-git-send-email-agraf@suse.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Mon, Sep 26, 2016 at 2:17 PM, Alexander Graf <agraf@suse.de> wrote: > The used compiler may or may not be recent enough to recognize the > crc32 extended cpu type. However, it does not really have to know about > them either, since all we do is pass inline assembly instructions to > the assembler. > > This patch moves the crc cpu extension detection from compiler based > to assembler based, so that we can build optimized code even when the > compiler does not know about the cpu type yet. > > Signed-off-by: Alexander Graf <agraf@suse.de> > --- > m4/ax_arm.m4 | 15 +++++++++++---- > src/common/Makefile.am | 2 +- > src/common/crc32c_aarch64.c | 3 +++ > 3 files changed, 15 insertions(+), 5 deletions(-) > > diff --git a/m4/ax_arm.m4 b/m4/ax_arm.m4 > index 37ea0aa..26b5258 100644 > --- a/m4/ax_arm.m4 > +++ b/m4/ax_arm.m4 > @@ -26,12 +26,19 @@ AC_DEFUN([AX_ARM_FEATURES], > AC_DEFINE(HAVE_NEON,,[Support NEON instructions]) > AC_SUBST(ARM_NEON_FLAGS) > fi > - AX_CHECK_COMPILE_FLAG(-march=armv8-a+crc, ax_cv_support_crc_ext=yes, []) > + > + AC_LANG_SAVE > + AC_LANG_CPLUSPLUS > + AC_CACHE_CHECK(whether the assembler supports crc extensions, > + ax_cv_support_crc_ext, AC_TRY_COMPILE([ > + #define CRC32CX(crc, value) __asm__("crc32cx %w[c], %w[c], %x[v]":[c]"+r"(crc):[v]"r"(value)) > + asm(".arch_extension crc"); > + unsigned int foo(unsigned int ret) { > + CRC32CX(ret, 0); > + return ret; > + }],[ foo(0); ], ax_cv_support_crc_ext=yes, [])) > if test x"$ax_cv_support_crc_ext" = x"yes"; then > - ARM_ARCH_FLAGS="$ARM_ARCH_FLAGS+crc" > - ARM_CRC_FLAGS="-march=armv8-a+crc -DARCH_AARCH64" > AC_DEFINE(HAVE_ARMV8_CRC,,[Support ARMv8 CRC instructions]) > - AC_SUBST(ARM_CRC_FLAGS) > fi > ARM_FLAGS="$ARM_ARCH_FLAGS $ARM_DEFINE_FLAGS" > ;; > diff --git a/src/common/Makefile.am b/src/common/Makefile.am > index 8b30eea..e92e51c 100644 > --- a/src/common/Makefile.am > +++ b/src/common/Makefile.am > @@ -144,7 +144,7 @@ noinst_LTLIBRARIES += libcommon_crc.la > > if HAVE_ARMV8_CRC > libcommon_crc_aarch64_la_SOURCES = common/crc32c_aarch64.c > -libcommon_crc_aarch64_la_CFLAGS = $(AM_CFLAGS) $(ARM_CRC_FLAGS) > +libcommon_crc_aarch64_la_CFLAGS = $(AM_CFLAGS) $(ARM_ARCH_FLAGS) > LIBCOMMON_DEPS += libcommon_crc_aarch64.la > noinst_LTLIBRARIES += libcommon_crc_aarch64.la > endif > diff --git a/src/common/crc32c_aarch64.c b/src/common/crc32c_aarch64.c > index d33827d..d2be6dd 100644 > --- a/src/common/crc32c_aarch64.c > +++ b/src/common/crc32c_aarch64.c > @@ -2,6 +2,9 @@ > #include "include/int_types.h" > #include "common/crc32c_aarch64.h" > > +/* Request crc extension capabilities from the assembler */ > +asm(".arch_extension crc"); > + > #define CRC32CX(crc, value) __asm__("crc32cx %w[c], %w[c], %x[v]":[c]"+r"(crc):[v]"r"(value)) > #define CRC32CW(crc, value) __asm__("crc32cw %w[c], %w[c], %w[v]":[c]"+r"(crc):[v]"r"(value)) > #define CRC32CH(crc, value) __asm__("crc32ch %w[c], %w[c], %w[v]":[c]"+r"(crc):[v]"r"(value)) Hi Alexander, We've been working on switching to cmake and actually ripped autotools out of master a couple of weeks ago, so this won't apply. Also, github pull requests are preferred for everything but the kernel client - less work for the reviewers. Thanks, Ilya -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
> We've been working on switching to cmake and actually ripped autotools > out of master a couple of weeks ago, so this won't apply. Keep it around, though, for the jewel backport ;-) Nathan -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/m4/ax_arm.m4 b/m4/ax_arm.m4 index 37ea0aa..26b5258 100644 --- a/m4/ax_arm.m4 +++ b/m4/ax_arm.m4 @@ -26,12 +26,19 @@ AC_DEFUN([AX_ARM_FEATURES], AC_DEFINE(HAVE_NEON,,[Support NEON instructions]) AC_SUBST(ARM_NEON_FLAGS) fi - AX_CHECK_COMPILE_FLAG(-march=armv8-a+crc, ax_cv_support_crc_ext=yes, []) + + AC_LANG_SAVE + AC_LANG_CPLUSPLUS + AC_CACHE_CHECK(whether the assembler supports crc extensions, + ax_cv_support_crc_ext, AC_TRY_COMPILE([ + #define CRC32CX(crc, value) __asm__("crc32cx %w[c], %w[c], %x[v]":[c]"+r"(crc):[v]"r"(value)) + asm(".arch_extension crc"); + unsigned int foo(unsigned int ret) { + CRC32CX(ret, 0); + return ret; + }],[ foo(0); ], ax_cv_support_crc_ext=yes, [])) if test x"$ax_cv_support_crc_ext" = x"yes"; then - ARM_ARCH_FLAGS="$ARM_ARCH_FLAGS+crc" - ARM_CRC_FLAGS="-march=armv8-a+crc -DARCH_AARCH64" AC_DEFINE(HAVE_ARMV8_CRC,,[Support ARMv8 CRC instructions]) - AC_SUBST(ARM_CRC_FLAGS) fi ARM_FLAGS="$ARM_ARCH_FLAGS $ARM_DEFINE_FLAGS" ;; diff --git a/src/common/Makefile.am b/src/common/Makefile.am index 8b30eea..e92e51c 100644 --- a/src/common/Makefile.am +++ b/src/common/Makefile.am @@ -144,7 +144,7 @@ noinst_LTLIBRARIES += libcommon_crc.la if HAVE_ARMV8_CRC libcommon_crc_aarch64_la_SOURCES = common/crc32c_aarch64.c -libcommon_crc_aarch64_la_CFLAGS = $(AM_CFLAGS) $(ARM_CRC_FLAGS) +libcommon_crc_aarch64_la_CFLAGS = $(AM_CFLAGS) $(ARM_ARCH_FLAGS) LIBCOMMON_DEPS += libcommon_crc_aarch64.la noinst_LTLIBRARIES += libcommon_crc_aarch64.la endif diff --git a/src/common/crc32c_aarch64.c b/src/common/crc32c_aarch64.c index d33827d..d2be6dd 100644 --- a/src/common/crc32c_aarch64.c +++ b/src/common/crc32c_aarch64.c @@ -2,6 +2,9 @@ #include "include/int_types.h" #include "common/crc32c_aarch64.h" +/* Request crc extension capabilities from the assembler */ +asm(".arch_extension crc"); + #define CRC32CX(crc, value) __asm__("crc32cx %w[c], %w[c], %x[v]":[c]"+r"(crc):[v]"r"(value)) #define CRC32CW(crc, value) __asm__("crc32cw %w[c], %w[c], %w[v]":[c]"+r"(crc):[v]"r"(value)) #define CRC32CH(crc, value) __asm__("crc32ch %w[c], %w[c], %w[v]":[c]"+r"(crc):[v]"r"(value))
The used compiler may or may not be recent enough to recognize the crc32 extended cpu type. However, it does not really have to know about them either, since all we do is pass inline assembly instructions to the assembler. This patch moves the crc cpu extension detection from compiler based to assembler based, so that we can build optimized code even when the compiler does not know about the cpu type yet. Signed-off-by: Alexander Graf <agraf@suse.de> --- m4/ax_arm.m4 | 15 +++++++++++---- src/common/Makefile.am | 2 +- src/common/crc32c_aarch64.c | 3 +++ 3 files changed, 15 insertions(+), 5 deletions(-)