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GNU C Library master sources branch release/2.26/master updated. glibc-2.26-190-gdc40423
- From: fw at sourceware dot org
- To: glibc-cvs at sourceware dot org
- Date: 2 Nov 2018 10:40:00 -0000
- Subject: GNU C Library master sources branch release/2.26/master updated. glibc-2.26-190-gdc40423
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http://sourceware.org/git/gitweb.cgi?p=glibc.git;a=commitdiff;h=dc40423dba7208ded2ec293c9a2938269f944ee8
commit dc40423dba7208ded2ec293c9a2938269f944ee8
Author: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Date: Fri Nov 2 11:14:05 2018 +0100
x86: Fix Haswell CPU string flags (BZ#23709)
Th commit 'Disable TSX on some Haswell processors.' (2702856bf4) changed the
default flags for Haswell models. Previously, new models were handled by the
default switch path, which assumed a Core i3/i5/i7 if AVX is available. After
the patch, Haswell models (0x3f, 0x3c, 0x45, 0x46) do not set the flags
Fast_Rep_String, Fast_Unaligned_Load, Fast_Unaligned_Copy, and
Prefer_PMINUB_for_stringop (only the TSX one).
This patch fixes it by disentangle the TSX flag handling from the memory
optimization ones. The strstr case cited on patch now selects the
__strstr_sse2_unaligned as expected for the Haswell cpu.
Checked on x86_64-linux-gnu.
[BZ #23709]
* sysdeps/x86/cpu-features.c (init_cpu_features): Set TSX bits
independently of other flags.
(cherry picked from commit c3d8dc45c9df199b8334599a6cbd98c9950dba62)
diff --git a/ChangeLog b/ChangeLog
index c6dfc5e..17a9232 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2018-10-23 Adhemerval Zanella <adhemerval.zanella@linaro.org>
+
+ [BZ #23709]
+ * sysdeps/x86/cpu-features.c (init_cpu_features): Set TSX bits
+ independently of other flags.
+
2017-12-18 Joseph Myers <joseph@codesourcery.com>
* nptl/tst-attr3.c: Include <libc-diag.h>.
diff --git a/NEWS b/NEWS
index f6c9a14..d99732f 100644
--- a/NEWS
+++ b/NEWS
@@ -156,6 +156,7 @@ The following bugs are resolved with this release:
[23459] COMMON_CPUID_INDEX_80000001 isn't populated for Intel processors
[23562] signal: Use correct type for si_band in siginfo_t
[23579] libc: Errors misreported in preadv2
+ [23709] Fix CPU string flags for Haswell-type CPUs
Version 2.26
diff --git a/sysdeps/x86/cpu-features.c b/sysdeps/x86/cpu-features.c
index a66d468..b3a5f4b 100644
--- a/sysdeps/x86/cpu-features.c
+++ b/sysdeps/x86/cpu-features.c
@@ -297,7 +297,13 @@ init_cpu_features (struct cpu_features *cpu_features)
| bit_arch_Fast_Unaligned_Copy
| bit_arch_Prefer_PMINUB_for_stringop);
break;
+ }
+ /* Disable TSX on some Haswell processors to avoid TSX on kernels that
+ weren't updated with the latest microcode package (which disables
+ broken feature by default). */
+ switch (model)
+ {
case 0x3f:
/* Xeon E7 v3 with stepping >= 4 has working TSX. */
if (stepping >= 4)
-----------------------------------------------------------------------
Summary of changes:
ChangeLog | 6 ++++++
NEWS | 1 +
sysdeps/x86/cpu-features.c | 6 ++++++
3 files changed, 13 insertions(+), 0 deletions(-)
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