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x86: Fix Haswell CPU string flags (BZ#23709)

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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)
This commit is contained in:
Adhemerval Zanella 2018-11-02 11:14:57 +01:00 committed by Florian Weimer
parent 5cd5309d91
commit d8eee5ef55
3 changed files with 13 additions and 0 deletions
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6
ChangeLog
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@ -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.
2018-10-26 Szabolcs Nagy <szabolcs.nagy@arm.com>
[BZ #23822]

1
NEWS
View File

@ -93,6 +93,7 @@ The following bugs are resolved with this release:
[23538] pthread_cond_broadcast: Fix waiters-after-spinning case
[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
[23821] si_band in siginfo_t has wrong type long int on sparc64
[23822] ia64 static libm.a is missing exp2f, log2f and powf symbols

6
sysdeps/x86/cpu-features.c
View File

@ -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)