From: Carlos O'Donell <carlos@redhat.com>
To: "H.J. Lu" <hjl.tools@gmail.com>,
Noah Goldstein <goldstein.w.n@gmail.com>
Cc: GNU C Library <libc-alpha@sourceware.org>
Subject: Re: [PATCH v3] x86: Fallback {str|wcs}cmp RTM in the ncmp overflow case [BZ #28896]
Date: Wed, 16 Feb 2022 09:08:07 -0500 [thread overview]
Message-ID: <867c131c-cec4-d8d6-5f24-cd51de94f1b2@redhat.com> (raw)
In-Reply-To: <CAMe9rOrvCEXVdcnQtSu_tvzzQcYAfv0qJ1ep4GzVdv5OY8Hb2g@mail.gmail.com>
On 2/16/22 08:17, H.J. Lu via Libc-alpha wrote:
> On Wed, Feb 16, 2022 at 12:09 AM Noah Goldstein <goldstein.w.n@gmail.com> wrote:
>>
>> In the overflow fallback strncmp-avx2-rtm and wcsncmp-avx2-rtm would
>> call strcmp-avx2 and wcsncmp-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>
>> ---
>> sysdeps/x86/Makefile | 2 +-
>> sysdeps/x86/tst-strncmp-rtm.c | 14 +++++++++++++-
>> sysdeps/x86_64/multiarch/strcmp-avx2.S | 8 ++------
>> 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, 20 insertions(+), 10 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..ebc94a3a6d 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 +46,19 @@ 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);
>> + return (do_test_1 ("strncmp", LOOP, prepare, function)
>> + || do_test_1 ("strncmp", LOOP, prepare, function_overflow));
>> }
>> diff --git a/sysdeps/x86_64/multiarch/strcmp-avx2.S b/sysdeps/x86_64/multiarch/strcmp-avx2.S
>> index 99e5349be8..6da0e1a248 100644
>> --- a/sysdeps/x86_64/multiarch/strcmp-avx2.S
>> +++ b/sysdeps/x86_64/multiarch/strcmp-avx2.S
>> @@ -193,10 +193,10 @@ L(ret_zero):
>> .p2align 4,, 5
>> L(one_or_less):
>> jb L(ret_zero)
>> -# ifdef USE_AS_WCSCMP
>> /* 'nbe' covers the case where length is negative (large
>> unsigned). */
>> - jnbe __wcscmp_avx2
>> + jnbe OVERFLOW_STRCMP
>> +# ifdef USE_AS_WCSCMP
>> movl (%rdi), %edx
>> xorl %eax, %eax
>> cmpl (%rsi), %edx
>> @@ -205,10 +205,6 @@ L(one_or_less):
>> negl %eax
>> orl $1, %eax
>> # else
>> - /* 'nbe' covers the case where length is negative (large
>> - unsigned). */
>> -
>> - jnbe __strcmp_avx2
>> movzbl (%rdi), %eax
>> movzbl (%rsi), %ecx
>> subl %ecx, %eax
>> 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"
>> --
>> 2.25.1
>>
>
> LGTM.
>
> Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
>
> Thanks.
>
This fails CI for i686.
https://patchwork.sourceware.org/project/glibc/patch/20220216080935.3284536-1-goldstein.w.n@gmail.com/
--
Cheers,
Carlos.
next prev parent reply other threads:[~2022-02-16 14:08 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-15 16:27 [PATCH v1] " Noah Goldstein
2022-02-15 16:29 ` H.J. Lu
2022-02-15 16:51 ` Noah Goldstein
2022-02-15 16:59 ` H.J. Lu
2022-02-15 17:06 ` Noah Goldstein
2022-02-15 18:49 ` H.J. Lu
2022-02-16 8:10 ` Noah Goldstein
2022-02-15 16:49 ` [PATCH v2] " Noah Goldstein
2022-02-16 8:09 ` [PATCH v3] " Noah Goldstein
2022-02-16 13:17 ` H.J. Lu
2022-02-16 14:08 ` Carlos O'Donell [this message]
2022-02-16 14:26 ` H.J. Lu
2022-02-17 19:15 ` Noah Goldstein
2022-02-17 19:12 ` [PATCH v4] " Noah Goldstein
2022-02-17 19:15 ` [PATCH v5] " Noah Goldstein
2022-02-17 19:20 ` H.J. Lu
2022-05-25 19:51 ` Sunil Pandey
2022-05-25 19:56 ` H.J. Lu
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