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| author | Adhemerval Zanella <adhemerval.zanella@linaro.org> | 2018-11-02 11:14:05 +0100 |
|---|---|---|
| committer | Florian Weimer <fweimer@redhat.com> | 2018-11-02 11:14:05 +0100 |
| commit | dc40423dba7208ded2ec293c9a2938269f944ee8 (patch) | |
| tree | f90e5d84b878a4fc8ef5b343e723248ca220b951 | |
| parent | 33f5de7a79b27b9dce30a46d6681974653a85004 (diff) | |
| download | glibc-dc40423dba7208ded2ec293c9a2938269f944ee8.tar.gz glibc-dc40423dba7208ded2ec293c9a2938269f944ee8.tar.xz glibc-dc40423dba7208ded2ec293c9a2938269f944ee8.zip | |
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)
| -rw-r--r-- | ChangeLog | 6 | ||||
| -rw-r--r-- | NEWS | 1 | ||||
| -rw-r--r-- | sysdeps/x86/cpu-features.c | 6 |
3 files changed, 13 insertions, 0 deletions
diff --git a/ChangeLog b/ChangeLog index c6dfc5e677..17a9232cdf 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 f6c9a1412c..d99732fe06 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 a66d468b20..b3a5f4b26a 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) |