[PATCH 11/11] powerpc64le: Add glibc-hwcaps support

Adhemerval Zanella adhemerval.zanella@linaro.org
Wed Dec 2 13:46:24 GMT 2020 


On 09/11/2020 15:41, Florian Weimer via Libc-alpha wrote:
> The "power10" and "power9" subdirectories are selected in a way
> that matches the -mcpu=power10 and -mcpu=power9 options of GCC.

LGTM, a comment about testing below.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>

> ---
>  elf/Makefile                                  |  2 +-
>  elf/tst-glibc-hwcaps-cache.script             |  6 +++
>  sysdeps/powerpc/powerpc64/le/Makefile         | 28 ++++++++++
>  .../powerpc/powerpc64/le/dl-hwcaps-subdirs.c  | 46 ++++++++++++++++
>  .../powerpc/powerpc64/le/tst-glibc-hwcaps.c   | 54 +++++++++++++++++++
>  5 files changed, 135 insertions(+), 1 deletion(-)
>  create mode 100644 sysdeps/powerpc/powerpc64/le/dl-hwcaps-subdirs.c
>  create mode 100644 sysdeps/powerpc/powerpc64/le/tst-glibc-hwcaps.c
> 
> diff --git a/elf/Makefile b/elf/Makefile
> index 0a44b19a0e..60e8662e5d 100644
> --- a/elf/Makefile
> +++ b/elf/Makefile
> @@ -1826,7 +1826,7 @@ $(objpfx)argv0test.out: tst-rtld-argv0.sh $(objpfx)ld.so \
>  
>  # Most likely search subdirectories, for each supported architecture.
>  # Used to obtain test coverage wide test coverage.
> -glibc-hwcaps-first-subdirs-for-tests = x86-64-v2
> +glibc-hwcaps-first-subdirs-for-tests = power9 x86-64-v2
>  
>  # The test modules are parameterized by preprocessor macros.
>  LDFLAGS-libmarkermod1-1.so += -Wl,-soname,libmarkermod1.so

Ok.

> diff --git a/elf/tst-glibc-hwcaps-cache.script b/elf/tst-glibc-hwcaps-cache.script
> index 2aef9fb177..a3e3317bbf 100644
> --- a/elf/tst-glibc-hwcaps-cache.script
> +++ b/elf/tst-glibc-hwcaps-cache.script
> @@ -10,3 +10,9 @@ mkdirp 0770 $L/glibc-hwcaps/x86-64-v4
>  cp $B/elf/libmarkermod4-2.so $L/glibc-hwcaps/x86-64-v2/libmarkermod4.so
>  cp $B/elf/libmarkermod4-3.so $L/glibc-hwcaps/x86-64-v3/libmarkermod4.so
>  cp $B/elf/libmarkermod4-4.so $L/glibc-hwcaps/x86-64-v4/libmarkermod4.so
> +
> +mkdirp 0770 $L/glibc-hwcaps/power9
> +cp $B/elf/libmarkermod2-2.so $L/glibc-hwcaps/power9/libmarkermod2.so
> +mkdirp 0770 $L/glibc-hwcaps/power10
> +cp $B/elf/libmarkermod3-2.so $L/glibc-hwcaps/power9/libmarkermod3.so
> +cp $B/elf/libmarkermod3-3.so $L/glibc-hwcaps/power10/libmarkermod3.so

Ok.

> diff --git a/sysdeps/powerpc/powerpc64/le/Makefile b/sysdeps/powerpc/powerpc64/le/Makefile
> index 033dc77b01..7c036b45fc 100644
> --- a/sysdeps/powerpc/powerpc64/le/Makefile
> +++ b/sysdeps/powerpc/powerpc64/le/Makefile
> @@ -188,3 +188,31 @@ ifeq ($(subdir),nptl)
>  CFLAGS-tst-thread_local1.cc += -mno-float128
>  CFLAGS-tst-minstack-throw.cc += -mno-float128
>  endif
> +
> +ifeq ($(subdir),elf)
> +$(objpfx)tst-glibc-hwcaps: \
> +  $(objpfx)libmarkermod2-1.so $(objpfx)libmarkermod3-1.so
> +$(objpfx)tst-glibc-hwcaps.out: \
> +  $(objpfx)libmarkermod2.so \
> +    $(objpfx)glibc-hwcaps/power9/libmarkermod2.so \
> +  $(objpfx)libmarkermod3.so \
> +    $(objpfx)glibc-hwcaps/power9/libmarkermod3.so \
> +    $(objpfx)glibc-hwcaps/power10/libmarkermod3.so \
> +
> +$(objpfx)glibc-hwcaps/power9/libmarkermod2.so: $(objpfx)libmarkermod2-2.so
> +	$(make-target-directory)
> +	cp $< $@
> +$(objpfx)glibc-hwcaps/power9/libmarkermod3.so: $(objpfx)libmarkermod3-2.so
> +	$(make-target-directory)
> +	cp $< $@
> +$(objpfx)glibc-hwcaps/power10/libmarkermod3.so: $(objpfx)libmarkermod3-3.so
> +	$(make-target-directory)
> +	cp $< $@
> +
> +ifeq (no,$(build-hardcoded-path-in-tests))
> +# This is an ld.so.cache test, and RPATH/RUNPATH in the executable
> +# interferes with its test objectives.
> +tests-container += tst-glibc-hwcaps-cache
> +endif
> +
> +endif # $(subdir) == elf

Ok.

> diff --git a/sysdeps/powerpc/powerpc64/le/dl-hwcaps-subdirs.c b/sysdeps/powerpc/powerpc64/le/dl-hwcaps-subdirs.c
> new file mode 100644
> index 0000000000..0ce76c2fe5
> --- /dev/null
> +++ b/sysdeps/powerpc/powerpc64/le/dl-hwcaps-subdirs.c
> @@ -0,0 +1,46 @@
> +/* Architecture-specific glibc-hwcaps subdirectories.  powerpc64le version.
> +   Copyright (C) 2020 Free Software Foundation, Inc.
> +   This file is part of the GNU C Library.
> +
> +   The GNU C Library is free software; you can redistribute it and/or
> +   modify it under the terms of the GNU Lesser General Public
> +   License as published by the Free Software Foundation; either
> +   version 2.1 of the License, or (at your option) any later version.
> +
> +   The GNU C Library is distributed in the hope that it will be useful,
> +   but WITHOUT ANY WARRANTY; without even the implied warranty of
> +   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> +   Lesser General Public License for more details.
> +
> +   You should have received a copy of the GNU Lesser General Public
> +   License along with the GNU C Library; if not, see
> +   <https://www.gnu.org/licenses/>.  */
> +
> +#include <dl-hwcaps.h>
> +#include <ldsodefs.h>
> +
> +const char _dl_hwcaps_subdirs[] = "power10:power9";
> +enum { subdirs_count = 2 }; /* Number of components in _dl_hwcaps_subdirs.  */
> +
> +uint32_t
> +_dl_hwcaps_subdirs_active (void)
> +{
> +  int active = 0;
> +
> +  /* Test in reverse preference order.  Altivec and VSX are implied by
> +     the powerpc64le ABI definition.  */
> +
> +  /* POWER9.  GCC enables float128 hardware support for -mcpu=power9.  */
> +  if ((GLRO (dl_hwcap2) & PPC_FEATURE2_ARCH_3_00) == 0
> +      || (GLRO (dl_hwcap2) & PPC_FEATURE2_HAS_IEEE128) == 0)
> +    return _dl_hwcaps_subdirs_build_bitmask (subdirs_count, active);
> +  ++active;

Should we test PPC_FEATURE2_DARN as well? I think cryptographic and related
libraries might use it as source of entropy.

> +
> +  /* POWER10. GCC defines __MMA__ for -mcpu=power10.  */

Double space after period.

> +  if ((GLRO (dl_hwcap2) & PPC_FEATURE2_ARCH_3_1) == 0
> +      || (GLRO (dl_hwcap2) & PPC_FEATURE2_MMA) == 0)
> +    return _dl_hwcaps_subdirs_build_bitmask (subdirs_count, active);
> +  ++active;
> +
> +  return _dl_hwcaps_subdirs_build_bitmask (subdirs_count, active);
> +}

Ok.

> diff --git a/sysdeps/powerpc/powerpc64/le/tst-glibc-hwcaps.c b/sysdeps/powerpc/powerpc64/le/tst-glibc-hwcaps.c
> new file mode 100644
> index 0000000000..e510fca80a
> --- /dev/null
> +++ b/sysdeps/powerpc/powerpc64/le/tst-glibc-hwcaps.c
> @@ -0,0 +1,54 @@
> +/* glibc-hwcaps subdirectory test.  powerpc64le version.
> +   Copyright (C) 2020 Free Software Foundation, Inc.
> +   This file is part of the GNU C Library.
> +
> +   The GNU C Library is free software; you can redistribute it and/or
> +   modify it under the terms of the GNU Lesser General Public
> +   License as published by the Free Software Foundation; either
> +   version 2.1 of the License, or (at your option) any later version.
> +
> +   The GNU C Library is distributed in the hope that it will be useful,
> +   but WITHOUT ANY WARRANTY; without even the implied warranty of
> +   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> +   Lesser General Public License for more details.
> +
> +   You should have received a copy of the GNU Lesser General Public
> +   License along with the GNU C Library; if not, see
> +   <https://www.gnu.org/licenses/>.  */
> +
> +#include <stdio.h>
> +#include <string.h>
> +#include <support/check.h>
> +#include <sys/auxv.h>
> +#include <sys/param.h>
> +
> +extern int marker2 (void);
> +extern int marker3 (void);
> +
> +/* Return the POWER level, 8 for the baseline.  */
> +static int
> +compute_level (void)
> +{
> +  const char *platform = (const char *) getauxval (AT_PLATFORM);
> +  if (strcmp (platform, "power8") == 0)
> +    return 8;
> +  if (strcmp (platform, "power9") == 0)
> +    return 9;
> +  if (strcmp (platform, "power10") == 0)
> +    return 10;

Why not use HWCAP? Is it to decouple from the loader code that uses it?
I am asking because by using hwcap we can check if this tests is working
on different chips by using qemu-ppc64le with -mcpu.

> +  printf ("warning: unrecognized AT_PLATFORM value: %s\n", platform);
> +  /* Assume that the new platform supports POWER10.  */
> +  return 10;
> +}
> +
> +static int
> +do_test (void)
> +{
> +  int level = compute_level ();
> +  printf ("info: detected POWER level: %d\n", level);
> +  TEST_COMPARE (marker2 (), MIN (level - 7, 2));
> +  TEST_COMPARE (marker3 (), MIN (level - 7, 3));
> +  return 0;
> +}
> +
> +#include <support/test-driver.c>
> 

Ok.

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