x86: Fallback {str|wcs}cmp RTM in the ncmp overflow case [BZ #28896]

In the overflow fallback strncmp-avx2-rtm and wcsncmp-avx2-rtm would
call strcmp-avx2 and wcscmp-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>

diff --git a/sysdeps/x86/Makefile b/sysdeps/x86/Makefile
index 6cf708335c169f128e33bab944c1e94d70fa6571..d110f7b7f2a437013f03cde545e3455e8049c5bf 100644 (file)
--- 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 09ed6fa0d66cab30b4e157fbf2aed18f19680b11..9e20abaaccfd57791dbc69066c13d82e01dffb96 100644 (file)
--- 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 +46,22 @@ 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 07a5a2c889b536fb753a2e512b3ad1306086baf0..52ff5ad724a78c2faf61d0758497ac5e3141c03a 100644 (file)
--- 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 37d1224bb9b7056bbfd47e3ac2bc3675aee3f1f4..68bad365ba728eecc879a847341ba7eb7e700be7 100644 (file)
--- 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 1678bcc235a4bc6a1c9715aa6a225a85d035df6b..f138e9f1fdcf277c35fd8fc54faf950a33464efb 100644 (file)
--- 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 4e88c70cc696b82d411b120b765a9e4532b05a41..f467582cbedd45357be8f4e37b66edf8ed4bd4c5 100644 (file)
--- 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 4fa1de4d3f1f97ff666164153c14ae3caa6d60aa..e9ede522b8bde27d1ebea2ad12aeca5b23442710 100644 (file)
--- 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"