From c3d8dc45c9df199b8334599a6cbd98c9950dba62 Mon Sep 17 00:00:00 2001 From: Adhemerval Zanella Date: Thu, 11 Oct 2018 15:18:40 -0300 Subject: [PATCH] x86: Fix Haswell strong 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. --- ChangeLog | 6 ++++++ sysdeps/x86/cpu-features.c | 6 ++++++ 2 files changed, 12 insertions(+) diff --git a/ChangeLog b/ChangeLog index c0fbf75d23..c5fe2a8527 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,9 @@ +2018-10-23 Adhemerval Zanella + + [BZ #23709] + * sysdeps/x86/cpu-features.c (init_cpu_features): Set TSX bits + independently of other flags. + 2018-10-23 Florian Weimer * time/tst-mktime2.c (N_STRINGS): Remove. diff --git a/sysdeps/x86/cpu-features.c b/sysdeps/x86/cpu-features.c index f4e0f5a2ed..80b3054cf8 100644 --- a/sysdeps/x86/cpu-features.c +++ b/sysdeps/x86/cpu-features.c @@ -316,7 +316,13 @@ 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)