x86: Fix bug in strchrnul-evex512 [BZ #32078]
(cherry picked from commit b3df4ce3b9d85aa30006b64edcc3c2979ee5e143)
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liqingqing_1229
openeuler-sync-bot
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@ -67,7 +67,7 @@
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##############################################################################
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Name: glibc
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Version: 2.38
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Release: 34
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Release: 35
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Summary: The GNU libc libraries
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License: %{all_license}
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URL: http://www.gnu.org/software/glibc/
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@ -213,6 +213,7 @@ Patch123: 0010-Add-mremap-tests.patch
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Patch124: 0011-Update-syscall-lists-for-Linux-6.5.patch
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Patch125: 0012-resolv-Fix-tst-resolv-short-response-for-older-GCC-b.patch
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Patch126: Fix-name-space-violation-in-fortify-wrappers-bug-320.patch
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Patch127: x86-Fix-bug-in-strchrnul-evex512-BZ-32078.patch
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#openEuler patch list
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Patch9000: turn-default-value-of-x86_rep_stosb_threshold_form_2K_to_1M.patch
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@ -1446,6 +1447,9 @@ fi
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%endif
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%changelog
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* Thu Aug 22 2024 Qingqing Li <liqingqing3@huawei.com> - 2.38-35
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- x86: Fix bug in strchrnul-evex512 [BZ #32078]
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* Fri Aug 9 2024 taoyuxiang <taoyuxiang2@huawei.com> - 2.38-34
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- Specify the GFDL version to GFDL-1.3-ONLY in spec
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162
x86-Fix-bug-in-strchrnul-evex512-BZ-32078.patch
Normal file
162
x86-Fix-bug-in-strchrnul-evex512-BZ-32078.patch
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@ -0,0 +1,162 @@
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From c005d1bd6f0e88ab4b822844d75d10c8978f5404 Mon Sep 17 00:00:00 2001
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From: Noah Goldstein <goldstein.w.n@gmail.com>
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Date: Tue, 13 Aug 2024 23:29:14 +0800
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Subject: [PATCH] x86: Fix bug in strchrnul-evex512 [BZ #32078]
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Issue was we were expecting not matches with CHAR before the start of
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the string in the page cross case.
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The check code in the page cross case:
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```
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and $0xffffffffffffffc0,%rax
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vmovdqa64 (%rax),%zmm17
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vpcmpneqb %zmm17,%zmm16,%k1
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vptestmb %zmm17,%zmm17,%k0{%k1}
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kmovq %k0,%rax
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inc %rax
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shr %cl,%rax
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je L(continue)
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```
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expects that all characters that neither match null nor CHAR will be
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1s in `rax` prior to the `inc`. Then the `inc` will overflow all of
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the 1s where no relevant match was found.
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This is incorrect in the page-cross case, as the
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`vmovdqa64 (%rax),%zmm17` loads from before the start of the input
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string.
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If there are matches with CHAR before the start of the string, `rax`
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won't properly overflow.
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The fix is quite simple. Just replace:
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```
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inc %rax
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shr %cl,%rax
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```
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With:
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```
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sar %cl,%rax
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inc %rax
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```
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The arithmetic shift will clear any matches prior to the start of the
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string while maintaining the signbit so the 1s can properly overflow
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to zero in the case of no matches.
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Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
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(cherry picked from commit 7da08862471dfec6fdae731c2a5f351ad485c71f)
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---
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string/test-strchr.c | 65 ++++++++++++++++++++-
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sysdeps/x86_64/multiarch/strchr-evex-base.S | 8 +--
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2 files changed, 68 insertions(+), 5 deletions(-)
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diff --git a/string/test-strchr.c b/string/test-strchr.c
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index 933fc0bbba..2bfcf901fa 100644
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--- a/string/test-strchr.c
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+++ b/string/test-strchr.c
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@@ -248,6 +248,69 @@ check1 (void)
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check_result (impl, s, c, exp_result);
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}
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+static void
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+check2 (void)
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+{
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+ CHAR *s = (CHAR *) (buf1 + getpagesize () - 4 * sizeof (CHAR));
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+ CHAR *s_begin = (CHAR *) (buf1 + getpagesize () - 64);
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+#ifndef USE_FOR_STRCHRNUL
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+ CHAR *exp_result = NULL;
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+#else
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+ CHAR *exp_result = s + 1;
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+#endif
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+ CHAR val = 0x12;
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+ for (; s_begin != s; ++s_begin)
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+ *s_begin = val;
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+
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+ s[0] = val + 1;
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+ s[1] = 0;
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+ s[2] = val + 1;
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+ s[3] = val + 1;
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+
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+ {
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+ FOR_EACH_IMPL (impl, 0)
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+ check_result (impl, s, val, exp_result);
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+ }
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+ s[3] = val;
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+ {
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+ FOR_EACH_IMPL (impl, 0)
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+ check_result (impl, s, val, exp_result);
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+ }
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+ exp_result = s;
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+ s[0] = val;
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+ {
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+ FOR_EACH_IMPL (impl, 0)
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+ check_result (impl, s, val, exp_result);
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+ }
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+
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+ s[3] = val + 1;
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+ {
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+ FOR_EACH_IMPL (impl, 0)
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+ check_result (impl, s, val, exp_result);
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+ }
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+
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+ s[0] = val + 1;
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+ s[1] = val + 1;
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+ s[2] = val + 1;
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+ s[3] = val + 1;
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+ s[4] = val;
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+ exp_result = s + 4;
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+ {
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+ FOR_EACH_IMPL (impl, 0)
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+ check_result (impl, s, val, exp_result);
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+ }
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+ s[4] = 0;
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+#ifndef USE_FOR_STRCHRNUL
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+ exp_result = NULL;
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+#else
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+ exp_result = s + 4;
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+#endif
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+ {
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+ FOR_EACH_IMPL (impl, 0)
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+ check_result (impl, s, val, exp_result);
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+ }
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+}
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+
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int
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test_main (void)
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{
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@@ -256,7 +319,7 @@ test_main (void)
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test_init ();
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check1 ();
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-
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+ check2 ();
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printf ("%20s", "");
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FOR_EACH_IMPL (impl, 0)
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printf ("\t%s", impl->name);
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diff --git a/sysdeps/x86_64/multiarch/strchr-evex-base.S b/sysdeps/x86_64/multiarch/strchr-evex-base.S
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index 7209435caf..da6d0eafbb 100644
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--- a/sysdeps/x86_64/multiarch/strchr-evex-base.S
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+++ b/sysdeps/x86_64/multiarch/strchr-evex-base.S
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@@ -124,13 +124,13 @@ L(page_cross):
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VPCMPNE %VMM(1), %VMM(0), %k1
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VPTEST %VMM(1), %VMM(1), %k0{%k1}
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KMOV %k0, %VRAX
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-# ifdef USE_AS_WCSCHR
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+ sar %cl, %VRAX
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+#ifdef USE_AS_WCSCHR
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sub $VEC_MATCH_MASK, %VRAX
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-# else
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+#else
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inc %VRAX
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-# endif
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+#endif
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/* Ignore number of character for alignment adjustment. */
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- shr %cl, %VRAX
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jz L(align_more)
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bsf %VRAX, %VRAX
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--
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2.33.0
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