[v2] x86: Fallback {str|wcs}cmp RTM in the ncmp overflow case [BZ #28896]
Checks
| Context |
Check |
Description |
| dj/TryBot-apply_patch |
success
|
Patch applied to master at the time it was sent
|
| dj/TryBot-32bit |
success
|
Build for i686
|
Commit Message
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. Note not tested on a machine that supports RTM (non
available).
---
Did not test the test case. I believe this will cover the bug
and is correct but do not have the hardware to check.
HJ, can you test this?
sysdeps/x86/tst-strncmp-rtm.c | 11 +++++++++++
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 +-
6 files changed, 17 insertions(+), 8 deletions(-)
@@ -45,8 +45,19 @@ 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_overflow);
}
@@ -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
@@ -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"
@@ -1,3 +1,4 @@
#define STRCMP __strncmp_avx2
#define USE_AS_STRNCMP 1
+#define OVERFLOW_STRCMP __strcmp_avx2
#include "strcmp-avx2.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"
@@ -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"