From: Hongtao Liu <crazylht@gmail.com>
To: liuhongt <hongtao.liu@intel.com>
Cc: gcc-patches@gcc.gnu.org, hjl.tools@gmail.com
Subject: Re: [PATCH] Software mitigation: Disable gather generation in vectorization for GDS affected Intel Processors.
Date: Wed, 16 Aug 2023 15:34:20 +0800 [thread overview]
Message-ID: <CAMZc-by7TMkuLVZ+QaX_HJJidNd4cTbZ_U8C0ZTm_97ORhpUdw@mail.gmail.com> (raw)
In-Reply-To: <20230811003810.2669080-1-hongtao.liu@intel.com>
On Fri, Aug 11, 2023 at 8:38 AM liuhongt <hongtao.liu@intel.com> wrote:
>
> For more details of GDS (Gather Data Sampling), refer to
> https://www.intel.com/content/www/us/en/developer/articles/technical/software-security-guidance/advisory-guidance/gather-data-sampling.html
>
> After microcode update, there's performance regression. To avoid that,
> the patch disables gather generation in autovectorization but uses
> gather scalar emulation instead.
>
> Ready push to trunk and backport.
> any comments?
Pushed to trunk and backport to releases/gcc-{11,12,13}.
>
> gcc/ChangeLog:
>
> * config/i386/i386-options.cc (m_GDS): New macro.
> * config/i386/x86-tune.def (X86_TUNE_USE_GATHER_2PARTS): Don't
> enable for m_GDS.
> (X86_TUNE_USE_GATHER_4PARTS): Ditto.
> (X86_TUNE_USE_GATHER): Ditto.
>
> gcc/testsuite/ChangeLog:
>
> * gcc.target/i386/avx2-gather-2.c: Adjust options to keep
> gather vectorization.
> * gcc.target/i386/avx2-gather-6.c: Ditto.
> * gcc.target/i386/avx512f-pr88464-1.c: Ditto.
> * gcc.target/i386/avx512f-pr88464-5.c: Ditto.
> * gcc.target/i386/avx512vl-pr88464-1.c: Ditto.
> * gcc.target/i386/avx512vl-pr88464-11.c: Ditto.
> * gcc.target/i386/avx512vl-pr88464-3.c: Ditto.
> * gcc.target/i386/avx512vl-pr88464-9.c: Ditto.
> * gcc.target/i386/pr88531-1b.c: Ditto.
> * gcc.target/i386/pr88531-1c.c: Ditto.
> ---
> gcc/config/i386/i386-options.cc | 5 +++++
> gcc/config/i386/x86-tune.def | 6 +++---
> gcc/testsuite/gcc.target/i386/avx2-gather-2.c | 2 +-
> gcc/testsuite/gcc.target/i386/avx2-gather-6.c | 2 +-
> gcc/testsuite/gcc.target/i386/avx512f-pr88464-1.c | 2 +-
> gcc/testsuite/gcc.target/i386/avx512f-pr88464-5.c | 2 +-
> gcc/testsuite/gcc.target/i386/avx512vl-pr88464-1.c | 2 +-
> gcc/testsuite/gcc.target/i386/avx512vl-pr88464-11.c | 2 +-
> gcc/testsuite/gcc.target/i386/avx512vl-pr88464-3.c | 2 +-
> gcc/testsuite/gcc.target/i386/avx512vl-pr88464-9.c | 2 +-
> gcc/testsuite/gcc.target/i386/pr88531-1b.c | 2 +-
> gcc/testsuite/gcc.target/i386/pr88531-1c.c | 2 +-
> 12 files changed, 18 insertions(+), 13 deletions(-)
>
> diff --git a/gcc/config/i386/i386-options.cc b/gcc/config/i386/i386-options.cc
> index 127ee24203c..e6ba33c370d 100644
> --- a/gcc/config/i386/i386-options.cc
> +++ b/gcc/config/i386/i386-options.cc
> @@ -141,6 +141,11 @@ along with GCC; see the file COPYING3. If not see
> #define m_ARROWLAKE (HOST_WIDE_INT_1U<<PROCESSOR_ARROWLAKE)
> #define m_CORE_ATOM (m_SIERRAFOREST | m_GRANDRIDGE)
> #define m_INTEL (HOST_WIDE_INT_1U<<PROCESSOR_INTEL)
> +/* Gather Data Sampling / CVE-2022-40982 / INTEL-SA-00828.
> + Software mitigation. */
> +#define m_GDS (m_SKYLAKE | m_SKYLAKE_AVX512 | m_CANNONLAKE \
> + | m_ICELAKE_CLIENT | m_ICELAKE_SERVER | m_CASCADELAKE \
> + | m_TIGERLAKE | m_COOPERLAKE | m_ROCKETLAKE)
>
> #define m_LUJIAZUI (HOST_WIDE_INT_1U<<PROCESSOR_LUJIAZUI)
>
> diff --git a/gcc/config/i386/x86-tune.def b/gcc/config/i386/x86-tune.def
> index 40e04ecddbf..22d26bb0030 100644
> --- a/gcc/config/i386/x86-tune.def
> +++ b/gcc/config/i386/x86-tune.def
> @@ -491,7 +491,7 @@ DEF_TUNE (X86_TUNE_AVOID_4BYTE_PREFIXES, "avoid_4byte_prefixes",
> elements. */
> DEF_TUNE (X86_TUNE_USE_GATHER_2PARTS, "use_gather_2parts",
> ~(m_ZNVER1 | m_ZNVER2 | m_ZNVER3 | m_ZNVER4 | m_ALDERLAKE
> - | m_ARROWLAKE | m_CORE_ATOM | m_GENERIC))
> + | m_ARROWLAKE | m_CORE_ATOM | m_GENERIC | m_GDS))
>
> /* X86_TUNE_USE_SCATTER_2PARTS: Use scater instructions for vectors with 2
> elements. */
> @@ -502,7 +502,7 @@ DEF_TUNE (X86_TUNE_USE_SCATTER_2PARTS, "use_scatter_2parts",
> elements. */
> DEF_TUNE (X86_TUNE_USE_GATHER_4PARTS, "use_gather_4parts",
> ~(m_ZNVER1 | m_ZNVER2 | m_ZNVER3 | m_ZNVER4 | m_ALDERLAKE
> - | m_ARROWLAKE | m_CORE_ATOM | m_GENERIC))
> + | m_ARROWLAKE | m_CORE_ATOM | m_GENERIC | m_GDS))
>
> /* X86_TUNE_USE_SCATTER_4PARTS: Use scater instructions for vectors with 4
> elements. */
> @@ -513,7 +513,7 @@ DEF_TUNE (X86_TUNE_USE_SCATTER_4PARTS, "use_scatter_4parts",
> elements. */
> DEF_TUNE (X86_TUNE_USE_GATHER, "use_gather",
> ~(m_ZNVER1 | m_ZNVER2 | m_ZNVER4 | m_ALDERLAKE | m_ARROWLAKE
> - | m_CORE_ATOM | m_GENERIC))
> + | m_CORE_ATOM | m_GENERIC | m_GDS))
>
> /* X86_TUNE_USE_SCATTER: Use scater instructions for vectors with 8 or more
> elements. */
> diff --git a/gcc/testsuite/gcc.target/i386/avx2-gather-2.c b/gcc/testsuite/gcc.target/i386/avx2-gather-2.c
> index ad5ef73107c..978924b0f57 100644
> --- a/gcc/testsuite/gcc.target/i386/avx2-gather-2.c
> +++ b/gcc/testsuite/gcc.target/i386/avx2-gather-2.c
> @@ -1,5 +1,5 @@
> /* { dg-do compile } */
> -/* { dg-options "-O3 -fdump-tree-vect-details -march=skylake" } */
> +/* { dg-options "-O3 -fdump-tree-vect-details -march=skylake -mtune=haswell" } */
>
> #include "avx2-gather-1.c"
>
> diff --git a/gcc/testsuite/gcc.target/i386/avx2-gather-6.c b/gcc/testsuite/gcc.target/i386/avx2-gather-6.c
> index 47a95dbe989..0bb40ac14eb 100644
> --- a/gcc/testsuite/gcc.target/i386/avx2-gather-6.c
> +++ b/gcc/testsuite/gcc.target/i386/avx2-gather-6.c
> @@ -1,5 +1,5 @@
> /* { dg-do compile } */
> -/* { dg-options "-O3 -mavx2 -fno-common -fdump-tree-vect-details -mtune=skylake -fno-split-loops" } */
> +/* { dg-options "-O3 -mavx2 -fno-common -fdump-tree-vect-details -mtune=haswell -fno-split-loops" } */
>
> #include "avx2-gather-5.c"
>
> diff --git a/gcc/testsuite/gcc.target/i386/avx512f-pr88464-1.c b/gcc/testsuite/gcc.target/i386/avx512f-pr88464-1.c
> index 06d21bb0129..d1a2298618e 100644
> --- a/gcc/testsuite/gcc.target/i386/avx512f-pr88464-1.c
> +++ b/gcc/testsuite/gcc.target/i386/avx512f-pr88464-1.c
> @@ -1,6 +1,6 @@
> /* PR tree-optimization/88464 */
> /* { dg-do compile } */
> -/* { dg-options "-O3 -mavx512f -mprefer-vector-width=512 -mtune=skylake-avx512 -fdump-tree-vect-details" } */
> +/* { dg-options "-O3 -mavx512f -mprefer-vector-width=512 -mtune=haswell -fdump-tree-vect-details" } */
> /* { dg-final { scan-tree-dump-times "loop vectorized using 64 byte vectors" 4 "vect" } } */
> /* { dg-final { scan-tree-dump-times "vectorized 1 loops in function" 4 "vect" } } */
>
> diff --git a/gcc/testsuite/gcc.target/i386/avx512f-pr88464-5.c b/gcc/testsuite/gcc.target/i386/avx512f-pr88464-5.c
> index 462e951fdc1..d7b0b2b28cb 100644
> --- a/gcc/testsuite/gcc.target/i386/avx512f-pr88464-5.c
> +++ b/gcc/testsuite/gcc.target/i386/avx512f-pr88464-5.c
> @@ -1,6 +1,6 @@
> /* PR tree-optimization/88464 */
> /* { dg-do compile } */
> -/* { dg-options "-O3 -mavx512f -mprefer-vector-width=512 -mtune=skylake-avx512 -fdump-tree-vect-details" } */
> +/* { dg-options "-O3 -mavx512f -mprefer-vector-width=512 -mtune=haswell -fdump-tree-vect-details" } */
> /* { dg-final { scan-tree-dump-times "loop vectorized using 64 byte vectors" 4 "vect" } } */
> /* { dg-final { scan-tree-dump-times "vectorized 1 loops in function" 4 "vect" } } */
>
> diff --git a/gcc/testsuite/gcc.target/i386/avx512vl-pr88464-1.c b/gcc/testsuite/gcc.target/i386/avx512vl-pr88464-1.c
> index 55a28dddbf8..07439185ec1 100644
> --- a/gcc/testsuite/gcc.target/i386/avx512vl-pr88464-1.c
> +++ b/gcc/testsuite/gcc.target/i386/avx512vl-pr88464-1.c
> @@ -1,6 +1,6 @@
> /* PR tree-optimization/88464 */
> /* { dg-do compile } */
> -/* { dg-options "-O3 -mavx512vl -mprefer-vector-width=256 -mtune=skylake-avx512 -fdump-tree-vect-details" } */
> +/* { dg-options "-O3 -mavx512vl -mprefer-vector-width=256 -mtune=haswell -fdump-tree-vect-details" } */
> /* { dg-final { scan-tree-dump-times "loop vectorized using 32 byte vectors" 4 "vect" } } */
> /* { dg-final { scan-tree-dump-times "vectorized 1 loops in function" 4 "vect" } } */
>
> diff --git a/gcc/testsuite/gcc.target/i386/avx512vl-pr88464-11.c b/gcc/testsuite/gcc.target/i386/avx512vl-pr88464-11.c
> index 9696008855d..3a98108279a 100644
> --- a/gcc/testsuite/gcc.target/i386/avx512vl-pr88464-11.c
> +++ b/gcc/testsuite/gcc.target/i386/avx512vl-pr88464-11.c
> @@ -1,6 +1,6 @@
> /* PR tree-optimization/88464 */
> /* { dg-do compile } */
> -/* { dg-options "-O3 -mavx512vl -mprefer-vector-width=128 -mtune=skylake-avx512 -fdump-tree-vect-details" } */
> +/* { dg-options "-O3 -mavx512vl -mprefer-vector-width=128 -mtune=haswell -fdump-tree-vect-details" } */
> /* { dg-final { scan-tree-dump-times "loop vectorized using 16 byte vectors" 4 "vect" } } */
> /* { dg-final { scan-tree-dump-times "vectorized 1 loops in function" 4 "vect" } } */
>
> diff --git a/gcc/testsuite/gcc.target/i386/avx512vl-pr88464-3.c b/gcc/testsuite/gcc.target/i386/avx512vl-pr88464-3.c
> index 6b0c8a85957..ac669e04812 100644
> --- a/gcc/testsuite/gcc.target/i386/avx512vl-pr88464-3.c
> +++ b/gcc/testsuite/gcc.target/i386/avx512vl-pr88464-3.c
> @@ -1,6 +1,6 @@
> /* PR tree-optimization/88464 */
> /* { dg-do compile } */
> -/* { dg-options "-O3 -mavx512vl -mprefer-vector-width=128 -mtune=skylake-avx512 -fdump-tree-vect-details" } */
> +/* { dg-options "-O3 -mavx512vl -mprefer-vector-width=128 -mtune=haswell -fdump-tree-vect-details" } */
> /* { dg-final { scan-tree-dump-times "loop vectorized using 16 byte vectors" 4 "vect" } } */
> /* { dg-final { scan-tree-dump-times "vectorized 1 loops in function" 4 "vect" } } */
>
> diff --git a/gcc/testsuite/gcc.target/i386/avx512vl-pr88464-9.c b/gcc/testsuite/gcc.target/i386/avx512vl-pr88464-9.c
> index 3af568ab323..14a1083b6d1 100644
> --- a/gcc/testsuite/gcc.target/i386/avx512vl-pr88464-9.c
> +++ b/gcc/testsuite/gcc.target/i386/avx512vl-pr88464-9.c
> @@ -1,6 +1,6 @@
> /* PR tree-optimization/88464 */
> /* { dg-do compile } */
> -/* { dg-options "-O3 -mavx512vl -mprefer-vector-width=256 -mtune=skylake-avx512 -fdump-tree-vect-details" } */
> +/* { dg-options "-O3 -mavx512vl -mprefer-vector-width=256 -mtune=haswell -fdump-tree-vect-details" } */
> /* { dg-final { scan-tree-dump-times "loop vectorized using 32 byte vectors" 4 "vect" } } */
> /* { dg-final { scan-tree-dump-times "vectorized 1 loops in function" 4 "vect" } } */
>
> diff --git a/gcc/testsuite/gcc.target/i386/pr88531-1b.c b/gcc/testsuite/gcc.target/i386/pr88531-1b.c
> index 812c8a10fab..e6df789de90 100644
> --- a/gcc/testsuite/gcc.target/i386/pr88531-1b.c
> +++ b/gcc/testsuite/gcc.target/i386/pr88531-1b.c
> @@ -1,5 +1,5 @@
> /* { dg-do compile } */
> -/* { dg-options "-O3 -march=skylake -mfpmath=sse" } */
> +/* { dg-options "-O3 -march=skylake -mfpmath=sse -mtune=haswell" } */
>
> #include "pr88531-1a.c"
>
> diff --git a/gcc/testsuite/gcc.target/i386/pr88531-1c.c b/gcc/testsuite/gcc.target/i386/pr88531-1c.c
> index 43fc5913ed3..a093c87c01f 100644
> --- a/gcc/testsuite/gcc.target/i386/pr88531-1c.c
> +++ b/gcc/testsuite/gcc.target/i386/pr88531-1c.c
> @@ -1,5 +1,5 @@
> /* { dg-do compile } */
> -/* { dg-options "-O3 -march=skylake-avx512 -mfpmath=sse" } */
> +/* { dg-options "-O3 -march=skylake-avx512 -mfpmath=sse -mtune=haswell" } */
>
> #include "pr88531-1a.c"
>
> --
> 2.31.1
>
--
BR,
Hongtao
prev parent reply other threads:[~2023-08-16 7:26 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-08-11 0:38 liuhongt
2023-08-16 7:34 ` Hongtao Liu [this message]
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