From: "H.J. Lu" <hjl.tools@gmail.com>
To: libc-alpha@sourceware.org
Subject: [PATCH v2] x86: Black list more Intel CPUs for TSX [BZ #27398]
Date: Tue, 18 Jan 2022 13:29:40 -0800 [thread overview]
Message-ID: <20220118212940.2051376-1-hjl.tools@gmail.com> (raw)
Disable TSX and enable RTM_ALWAYS_ABORT for Intel CPUs listed in:
https://www.intel.com/content/www/us/en/support/articles/000059422/processors.html
This fixes BZ #27398.
---
sysdeps/x86/cpu-features.c | 34 +++++++++++++++++++++++++++++++---
1 file changed, 31 insertions(+), 3 deletions(-)
diff --git a/sysdeps/x86/cpu-features.c b/sysdeps/x86/cpu-features.c
index 772ccf8e91..514226b378 100644
--- a/sysdeps/x86/cpu-features.c
+++ b/sysdeps/x86/cpu-features.c
@@ -507,11 +507,39 @@ init_cpu_features (struct cpu_features *cpu_features)
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). */
+ /* Disable TSX on some processors to avoid TSX on kernels that
+ weren't updated with the latest microcode package (which
+ disables broken feature by default). */
switch (model)
{
+ case 0x55:
+ if (stepping <= 5)
+ goto disable_tsx;
+ break;
+ case 0x8e:
+ /* NB: Although the errata documents that for model == 0x8e,
+ only 0xb stepping or lower are impacted, the intention of
+ the errata was to disable TSX on all client processors on
+ all steppings. Include 0xc stepping which is an Intel
+ Core i7-8665U, a client mobile processor. */
+ case 0x9e:
+ if (stepping > 0xc)
+ break;
+ /* Fall through. */
+ case 0x4e:
+ case 0x5e:
+ {
+ /* Disable Intel TSX and enable RTM_ALWAYS_ABORT for
+ processors listed in:
+
+https://www.intel.com/content/www/us/en/support/articles/000059422/processors.html
+ */
+disable_tsx:
+ CPU_FEATURE_UNSET (cpu_features, HLE);
+ CPU_FEATURE_UNSET (cpu_features, RTM);
+ CPU_FEATURE_SET (cpu_features, RTM_ALWAYS_ABORT);
+ }
+ break;
case 0x3f:
/* Xeon E7 v3 with stepping >= 4 has working TSX. */
if (stepping >= 4)
--
2.34.1
next reply other threads:[~2022-01-18 21:29 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-18 21:29 H.J. Lu [this message]
2022-01-18 21:51 ` Noah Goldstein
2022-02-01 13:42 ` H.J. Lu
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