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[76.191.17.161]) by smtp.googlemail.com with ESMTPSA id p11sm2831859iov.38.2022.02.17.11.15.31 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 17 Feb 2022 11:15:32 -0800 (PST) From: Noah Goldstein To: libc-alpha@sourceware.org Subject: [PATCH v5] x86: Fallback {str|wcs}cmp RTM in the ncmp overflow case [BZ #28896] Date: Thu, 17 Feb 2022 13:15:24 -0600 Message-Id: <20220217191524.2961663-1-goldstein.w.n@gmail.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20220215162751.281955-1-goldstein.w.n@gmail.com> References: <20220215162751.281955-1-goldstein.w.n@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Spam-Status: No, score=-12.6 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, FREEMAIL_FROM, GIT_PATCH_0, KAM_SHORT, RCVD_IN_DNSWL_NONE, SPF_HELO_NONE, SPF_PASS, TXREP, T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.4 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on server2.sourceware.org X-BeenThere: libc-alpha@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 17 Feb 2022 19:15:35 -0000 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 --- sysdeps/x86/Makefile | 2 +- sysdeps/x86/tst-strncmp-rtm.c | 17 ++++++++++++++++- 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, 23 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..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 . */ +#include #include #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; } 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