[PATCH v4 09/10] x86: Check ifunc resolver with CPU_FEATURE_USABLE [BZ #27072]

Adhemerval Zanella adhemerval.zanella@linaro.org
Tue Jan 19 14:11:54 GMT 2021



On 18/01/2021 13:25, Szabolcs Nagy via Libc-alpha wrote:
> From: "H.J. Lu" <hjl.tools@gmail.com>
> 
> Check ifunc resolver with CPU_FEATURE_USABLE and tunables in dynamic and
> static executables to verify that CPUID features are initialized early in
> static PIE.

LGTM, thanks.  Maybe refactor the tests to use a common file with the
ifunc definitions, since both a copying and pasting similar code.

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

> ---
>  sysdeps/x86/Makefile                 |  14 ++++
>  sysdeps/x86/tst-ifunc-isa-1-static.c |   1 +
>  sysdeps/x86/tst-ifunc-isa-1.c        | 115 ++++++++++++++++++++++++++
>  sysdeps/x86/tst-ifunc-isa-2-static.c |   1 +
>  sysdeps/x86/tst-ifunc-isa-2.c        | 119 +++++++++++++++++++++++++++
>  5 files changed, 250 insertions(+)
>  create mode 100644 sysdeps/x86/tst-ifunc-isa-1-static.c
>  create mode 100644 sysdeps/x86/tst-ifunc-isa-1.c
>  create mode 100644 sysdeps/x86/tst-ifunc-isa-2-static.c
>  create mode 100644 sysdeps/x86/tst-ifunc-isa-2.c
> 
> diff --git a/sysdeps/x86/Makefile b/sysdeps/x86/Makefile
> index adaa2a92cd..f7969309bc 100644
> --- a/sysdeps/x86/Makefile
> +++ b/sysdeps/x86/Makefile
> @@ -9,6 +9,16 @@ sysdep_headers += sys/platform/x86.h
>  tests += tst-get-cpu-features tst-get-cpu-features-static \
>  	 tst-cpu-features-cpuinfo tst-cpu-features-supports
>  tests-static += tst-get-cpu-features-static
> +ifeq (yes,$(have-ifunc))
> +tests += \
> +  tst-ifunc-isa-1 \
> +  tst-ifunc-isa-1-static \
> +  tst-ifunc-isa-2 \
> +  tst-ifunc-isa-2-static
> +tests-static += \
> +  tst-ifunc-isa-1-static \
> +  tst-ifunc-isa-2-static
> +endif
>  ifeq (yes,$(enable-x86-isa-level))
>  tests += tst-isa-level-1
>  modules-names += tst-isa-level-mod-1-baseline \
> @@ -39,6 +49,10 @@ $(objpfx)tst-isa-level-1.out: $(objpfx)tst-isa-level-mod-1-baseline.so \
>  			      $(objpfx)tst-isa-level-mod-1-v3.so \
>  			      $(objpfx)tst-isa-level-mod-1-v4.so
>  endif
> +ifneq ($(have-tunables),no)
> +tst-ifunc-isa-2-ENV = GLIBC_TUNABLES=glibc.cpu.hwcaps=-SSE4_2,-AVX,-AVX2,-AVX512F
> +tst-ifunc-isa-2-static-ENV = $(tst-ifunc-isa-2-ENV)
> +endif
>  endif
>  
>  ifeq ($(subdir),math)

Ok.

> diff --git a/sysdeps/x86/tst-ifunc-isa-1-static.c b/sysdeps/x86/tst-ifunc-isa-1-static.c
> new file mode 100644
> index 0000000000..0e94f6119b
> --- /dev/null
> +++ b/sysdeps/x86/tst-ifunc-isa-1-static.c
> @@ -0,0 +1 @@
> +#include "tst-ifunc-isa-1.c"

Ok.

> diff --git a/sysdeps/x86/tst-ifunc-isa-1.c b/sysdeps/x86/tst-ifunc-isa-1.c
> new file mode 100644
> index 0000000000..b3bc2a55a2
> --- /dev/null
> +++ b/sysdeps/x86/tst-ifunc-isa-1.c
> @@ -0,0 +1,115 @@
> +/* Check ifunc with CPU_FEATURE_USABLE.
> +   Copyright (C) 2021 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 <stdlib.h>
> +#include <sys/platform/x86.h>
> +
> +enum isa
> +{
> +  none,
> +  sse2,
> +  sse4_2,
> +  avx,
> +  avx2,
> +  avx512f
> +};
> +
> +enum isa
> +get_isa (void)
> +{
> +  if (CPU_FEATURE_USABLE (AVX512F))
> +    return avx512f;
> +  if (CPU_FEATURE_USABLE (AVX2))
> +    return avx2;
> +  if (CPU_FEATURE_USABLE (AVX))
> +    return avx;
> +  if (CPU_FEATURE_USABLE (SSE4_2))
> +    return sse4_2;
> +  if (CPU_FEATURE_USABLE (SSE2))
> +    return sse2;
> +  return none;
> +}
> +
> +static int
> +isa_sse2 (void)
> +{
> +  return sse2;
> +}
> +
> +static int
> +isa_sse4_2 (void)
> +{
> +  return sse4_2;
> +}
> +
> +static int
> +isa_avx (void)
> +{
> +  return avx;
> +}
> +
> +static int
> +isa_avx2 (void)
> +{
> +  return avx2;
> +}
> +
> +static int
> +isa_avx512f (void)
> +{
> +  return avx512f;
> +}
> +
> +static int
> +isa_none (void)
> +{
> +  return none;
> +}
> +
> +int foo (void) __attribute__ ((ifunc ("foo_ifunc")));
> +
> +void *
> +foo_ifunc (void)
> +{
> +  switch (get_isa ())
> +    {
> +    case avx512f:
> +      return isa_avx512f;
> +    case avx2:
> +      return isa_avx2;
> +    case avx:
> +      return isa_avx;
> +    case sse4_2:
> +      return isa_sse4_2;
> +    case sse2:
> +      return isa_sse2;
> +    default:
> +      break;
> +    }
> +  return isa_none;
> +}
> +
> +static int
> +do_test (void)
> +{
> +  enum isa value = foo ();
> +  enum isa expected = get_isa ();
> +  return value == expected ? EXIT_SUCCESS : EXIT_FAILURE;
> +}
> +
> +#include <support/test-driver.c>

Ok.

> diff --git a/sysdeps/x86/tst-ifunc-isa-2-static.c b/sysdeps/x86/tst-ifunc-isa-2-static.c
> new file mode 100644
> index 0000000000..4a5af9a270
> --- /dev/null
> +++ b/sysdeps/x86/tst-ifunc-isa-2-static.c
> @@ -0,0 +1 @@
> +#include "tst-ifunc-isa-2.c"

Ok.

> diff --git a/sysdeps/x86/tst-ifunc-isa-2.c b/sysdeps/x86/tst-ifunc-isa-2.c
> new file mode 100644
> index 0000000000..bb0f76c3e4
> --- /dev/null
> +++ b/sysdeps/x86/tst-ifunc-isa-2.c
> @@ -0,0 +1,119 @@
> +/* Check ifunc with CPU_FEATURE_USABLE and tunables.
> +   Copyright (C) 2021 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 <stdlib.h>
> +#include <sys/platform/x86.h>
> +#include <support/test-driver.h>
> +
> +enum isa
> +{
> +  none,
> +  sse2,
> +  sse4_2,
> +  avx,
> +  avx2,
> +  avx512f
> +};
> +
> +enum isa
> +get_isa (void)
> +{
> +  if (CPU_FEATURE_USABLE (AVX512F))
> +    return avx512f;
> +  if (CPU_FEATURE_USABLE (AVX2))
> +    return avx2;
> +  if (CPU_FEATURE_USABLE (AVX))
> +    return avx;
> +  if (CPU_FEATURE_USABLE (SSE4_2))
> +    return sse4_2;
> +  if (CPU_FEATURE_USABLE (SSE2))
> +    return sse2;
> +  return none;
> +}
> +
> +static int
> +isa_sse2 (void)
> +{
> +  return sse2;
> +}
> +
> +static int
> +isa_sse4_2 (void)
> +{
> +  return sse4_2;
> +}
> +
> +static int
> +isa_avx (void)
> +{
> +  return avx;
> +}
> +
> +static int
> +isa_avx2 (void)
> +{
> +  return avx2;
> +}
> +
> +static int
> +isa_avx512f (void)
> +{
> +  return avx512f;
> +}
> +
> +static int
> +isa_none (void)
> +{
> +  return none;
> +}
> +
> +int foo (void) __attribute__ ((ifunc ("foo_ifunc")));
> +
> +void *
> +foo_ifunc (void)
> +{
> +  switch (get_isa ())
> +    {
> +    case avx512f:
> +      return isa_avx512f;
> +    case avx2:
> +      return isa_avx2;
> +    case avx:
> +      return isa_avx;
> +    case sse4_2:
> +      return isa_sse4_2;
> +    case sse2:
> +      return isa_sse2;
> +    default:
> +      break;
> +    }
> +  return isa_none;
> +}
> +

Maybe move this part to a common file?

> +static int
> +do_test (void)
> +{
> +  /* CPU must support SSE2.  */
> +  if (!__builtin_cpu_supports ("sse2"))
> +    return EXIT_UNSUPPORTED;
> +  enum isa value = foo ();
> +  /* All ISAs, but SSE2, are disabled by tunables.  */
> +  return value == sse2 ? EXIT_SUCCESS : EXIT_FAILURE;
> +}
> +
> +#include <support/test-driver.c>
> 

Ok.


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