From: Noah Goldstein <goldstein.w.n@gmail.com>
To: "H.J. Lu" <hjl.tools@gmail.com>
Cc: "Carlos O'Donell" <carlos@redhat.com>,
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: Thu, 17 Feb 2022 13:15:50 -0600 [thread overview]
Message-ID: <CAFUsyfJ5Zb0ppKAj--eo+e8bgJ8+xSbWBv0zB62AH25x3YgbSQ@mail.gmail.com> (raw)
In-Reply-To: <CAMe9rOp+j+PnTkKGXUj0zwYVg2OGNmNoAqKFzfVa9ZguZFT=pA@mail.gmail.com>
On Wed, Feb 16, 2022 at 8:27 AM H.J. Lu <hjl.tools@gmail.com> wrote:
>
> On Wed, Feb 16, 2022 at 6:08 AM Carlos O'Donell <carlos@redhat.com> wrote:
> >
> > 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.
> >
>
> Hi Noah,
>
> We need this change on top of your patch:
>
> diff --git a/sysdeps/x86/tst-strncmp-rtm.c b/sysdeps/x86/tst-strncmp-rtm.c
> index ebc94a3a6d..9e20abaacc 100644
> --- a/sysdeps/x86/tst-strncmp-rtm.c
> +++ b/sysdeps/x86/tst-strncmp-rtm.c
> @@ -59,6 +59,9 @@ function_overflow (void)
> static int
> do_test (void)
> {
> - return (do_test_1 ("strncmp", LOOP, prepare, function)
> - || do_test_1 ("strncmp", LOOP, prepare, function_overflow));
> + 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;
> }
Added your fix in V5.
>
> --
> H.J.
next prev parent reply other threads:[~2022-02-17 19:16 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
2022-02-16 14:26 ` H.J. Lu
2022-02-17 19:15 ` Noah Goldstein [this message]
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
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=CAFUsyfJ5Zb0ppKAj--eo+e8bgJ8+xSbWBv0zB62AH25x3YgbSQ@mail.gmail.com \
--to=goldstein.w.n@gmail.com \
--cc=carlos@redhat.com \
--cc=hjl.tools@gmail.com \
--cc=libc-alpha@sourceware.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).