From: "H.J. Lu" <hjl.tools@gmail.com>
To: Noah Goldstein <goldstein.w.n@gmail.com>
Cc: GNU C Library <libc-alpha@sourceware.org>,
"Carlos O'Donell" <carlos@systemhalted.org>
Subject: Re: [PATCH v1] x86: Fallback {str|wcs}cmp RTM in the ncmp overflow case [BZ #28896]
Date: Tue, 15 Feb 2022 08:59:56 -0800 [thread overview]
Message-ID: <CAMe9rOrwYcZPx5qZWDJ2CO1WQN7H=pp027VVPpvWjH1MKVBbGA@mail.gmail.com> (raw)
In-Reply-To: <CAFUsyfJtusOvBskquxiZVKCr4fTqv8vWiqYnOP8TQ8fvyqjkAw@mail.gmail.com>
On Tue, Feb 15, 2022 at 8:51 AM Noah Goldstein <goldstein.w.n@gmail.com> wrote:
>
> On Tue, Feb 15, 2022 at 10:30 AM H.J. Lu <hjl.tools@gmail.com> wrote:
> >
> > On Tue, Feb 15, 2022 at 8:28 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.
> >
> > Include a testcase?
> Added test case in V2. Don't have the hardware to check it though,
> can you?
Yes, I can. Please V2 on a branch in gitlab.
Thanks.
> >
> > > test-strcmp, test-strncmp, test-wcscmp, and test-wcsncmp all
> > > pass. Note not tested on a machine that supports RTM (non
> > > available).
> > > ---
> > > 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 +-
> > > 5 files changed, 6 insertions(+), 8 deletions(-)
> > >
> > > diff --git a/sysdeps/x86_64/multiarch/strcmp-avx2.S b/sysdeps/x86_64/multiarch/strcmp-avx2.S
> > > index 07a5a2c889..52ff5ad724 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
> > >
> >
> >
> > --
> > H.J.
--
H.J.
next prev parent reply other threads:[~2022-02-15 17:00 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-15 16:27 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 [this message]
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
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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