From: Noah Goldstein <goldstein.w.n@gmail.com>
To: "H.J. Lu" <hjl.tools@gmail.com>
Cc: Stable GNU C Library <libc-stable@sourceware.org>
Subject: Re: [Backport PATCH 1/2] x86: Fallback {str|wcs}cmp RTM in the ncmp overflow case [BZ #28896]
Date: Fri, 18 Feb 2022 16:56:45 -0600 [thread overview]
Message-ID: <CAFUsyf+LEycaXE3i3Qgrh2k7q5nC-ENoHUCBYsJEr_b66x7ewA@mail.gmail.com> (raw)
In-Reply-To: <YhAj3J0SlF2DJHkv@gmail.com>
On Fri, Feb 18, 2022 at 4:55 PM H.J. Lu <hjl.tools@gmail.com> wrote:
>
> In the overflow fallback strncmp-avx2-rtm and wcsncmp-avx2-rtm would
> call strcmp-avx2 and wcscmp-avx2 respectively. This would have
> not checks around vzeroupper and would trigger spurious
> aborts. This commit fixes that.
>
> test-strcmp, test-strncmp, test-wcscmp, and test-wcsncmp all pass on
> AVX2 machines with and without RTM.
>
> Co-authored-by: H.J. Lu <hjl.tools@gmail.com>
>
> (cherry picked from commit c6272098323153db373f2986c67786ea8c85f1cf)
> ---
> sysdeps/x86/Makefile | 2 +-
> sysdeps/x86/tst-strncmp-rtm.c | 17 ++++++++++++++++-
> sysdeps/x86_64/multiarch/strcmp-avx2.S | 2 +-
> sysdeps/x86_64/multiarch/strncmp-avx2-rtm.S | 1 +
> sysdeps/x86_64/multiarch/strncmp-avx2.S | 1 +
> sysdeps/x86_64/multiarch/wcsncmp-avx2-rtm.S | 2 +-
> sysdeps/x86_64/multiarch/wcsncmp-avx2.S | 2 +-
> 7 files changed, 22 insertions(+), 5 deletions(-)
>
> diff --git a/sysdeps/x86/Makefile b/sysdeps/x86/Makefile
> index 6cf708335c..d110f7b7f2 100644
> --- a/sysdeps/x86/Makefile
> +++ b/sysdeps/x86/Makefile
> @@ -109,7 +109,7 @@ CFLAGS-tst-memset-rtm.c += -mrtm
> CFLAGS-tst-strchr-rtm.c += -mrtm
> CFLAGS-tst-strcpy-rtm.c += -mrtm
> CFLAGS-tst-strlen-rtm.c += -mrtm
> -CFLAGS-tst-strncmp-rtm.c += -mrtm
> +CFLAGS-tst-strncmp-rtm.c += -mrtm -Wno-error
> CFLAGS-tst-strrchr-rtm.c += -mrtm
> endif
>
> diff --git a/sysdeps/x86/tst-strncmp-rtm.c b/sysdeps/x86/tst-strncmp-rtm.c
> index 09ed6fa0d6..9e20abaacc 100644
> --- a/sysdeps/x86/tst-strncmp-rtm.c
> +++ b/sysdeps/x86/tst-strncmp-rtm.c
> @@ -16,6 +16,7 @@
> License along with the GNU C Library; if not, see
> <https://www.gnu.org/licenses/>. */
>
> +#include <stdint.h>
> #include <tst-string-rtm.h>
>
> #define LOOP 3000
> @@ -45,8 +46,22 @@ function (void)
> return 1;
> }
>
> +__attribute__ ((noinline, noclone))
> +static int
> +function_overflow (void)
> +{
> + if (strncmp (string1, string2, SIZE_MAX) == 0)
> + return 0;
> + else
> + return 1;
> +}
> +
> static int
> do_test (void)
> {
> - return do_test_1 ("strncmp", LOOP, prepare, function);
> + int status = do_test_1 ("strncmp", LOOP, prepare, function);
> + if (status != EXIT_SUCCESS)
> + return status;
> + status = do_test_1 ("strncmp", LOOP, prepare, function_overflow);
> + return status;
> }
Are we including the wcsncmp tests?
> diff --git a/sysdeps/x86_64/multiarch/strcmp-avx2.S b/sysdeps/x86_64/multiarch/strcmp-avx2.S
> index 9c73b5899d..cdcb3c5a26 100644
> --- a/sysdeps/x86_64/multiarch/strcmp-avx2.S
> +++ b/sysdeps/x86_64/multiarch/strcmp-avx2.S
> @@ -95,7 +95,7 @@ ENTRY (STRCMP)
> length to bound a valid memory region. In these cases just use
> 'wcscmp'. */
> shrq $56, %rcx
> - jnz __wcscmp_avx2
> + jnz OVERFLOW_STRCMP
> # endif
> /* Convert units: from wide to byte char. */
> shl $2, %RDX_LP
> diff --git a/sysdeps/x86_64/multiarch/strncmp-avx2-rtm.S b/sysdeps/x86_64/multiarch/strncmp-avx2-rtm.S
> index 37d1224bb9..68bad365ba 100644
> --- a/sysdeps/x86_64/multiarch/strncmp-avx2-rtm.S
> +++ b/sysdeps/x86_64/multiarch/strncmp-avx2-rtm.S
> @@ -1,3 +1,4 @@
> #define STRCMP __strncmp_avx2_rtm
> #define USE_AS_STRNCMP 1
> +#define OVERFLOW_STRCMP __strcmp_avx2_rtm
> #include "strcmp-avx2-rtm.S"
> diff --git a/sysdeps/x86_64/multiarch/strncmp-avx2.S b/sysdeps/x86_64/multiarch/strncmp-avx2.S
> index 1678bcc235..f138e9f1fd 100644
> --- a/sysdeps/x86_64/multiarch/strncmp-avx2.S
> +++ b/sysdeps/x86_64/multiarch/strncmp-avx2.S
> @@ -1,3 +1,4 @@
> #define STRCMP __strncmp_avx2
> #define USE_AS_STRNCMP 1
> +#define OVERFLOW_STRCMP __strcmp_avx2
> #include "strcmp-avx2.S"
> diff --git a/sysdeps/x86_64/multiarch/wcsncmp-avx2-rtm.S b/sysdeps/x86_64/multiarch/wcsncmp-avx2-rtm.S
> index 4e88c70cc6..f467582cbe 100644
> --- a/sysdeps/x86_64/multiarch/wcsncmp-avx2-rtm.S
> +++ b/sysdeps/x86_64/multiarch/wcsncmp-avx2-rtm.S
> @@ -1,5 +1,5 @@
> #define STRCMP __wcsncmp_avx2_rtm
> #define USE_AS_STRNCMP 1
> #define USE_AS_WCSCMP 1
> -
> +#define OVERFLOW_STRCMP __wcscmp_avx2_rtm
> #include "strcmp-avx2-rtm.S"
> diff --git a/sysdeps/x86_64/multiarch/wcsncmp-avx2.S b/sysdeps/x86_64/multiarch/wcsncmp-avx2.S
> index 4fa1de4d3f..e9ede522b8 100644
> --- a/sysdeps/x86_64/multiarch/wcsncmp-avx2.S
> +++ b/sysdeps/x86_64/multiarch/wcsncmp-avx2.S
> @@ -1,5 +1,5 @@
> #define STRCMP __wcsncmp_avx2
> #define USE_AS_STRNCMP 1
> #define USE_AS_WCSCMP 1
> -
> +#define OVERFLOW_STRCMP __wcscmp_avx2
> #include "strcmp-avx2.S"
> --
> 2.35.1
>
prev parent reply other threads:[~2022-02-18 22:56 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-18 22:55 H.J. Lu
2022-02-18 22:56 ` Noah Goldstein [this message]
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