about summary refs log tree commit diff
path: root/sysdeps/x86/include
diff options
context:
space:
mode:
authorH.J. Lu <hjl.tools@gmail.com>2021-06-30 10:47:06 -0700
committerH.J. Lu <hjl.tools@gmail.com>2021-07-01 10:47:35 -0700
commitea8e465a6b8d0f26c72bcbe453a854de3abf68ec (patch)
treef0b6b62b393ea4715f75248e5425d088a8aeba14 /sysdeps/x86/include
parentb1b4f7209ecaad4bf9a5d0d2ef1338409d364bac (diff)
downloadglibc-ea8e465a6b8d0f26c72bcbe453a854de3abf68ec.tar.gz
glibc-ea8e465a6b8d0f26c72bcbe453a854de3abf68ec.tar.xz
glibc-ea8e465a6b8d0f26c72bcbe453a854de3abf68ec.zip
x86: Check RTM_ALWAYS_ABORT for RTM [BZ #28033]
From

https://www.intel.com/content/www/us/en/support/articles/000059422/processors.html

* Intel TSX will be disabled by default.
* The processor will force abort all Restricted Transactional Memory (RTM)
  transactions by default.
* A new CPUID bit CPUID.07H.0H.EDX[11](RTM_ALWAYS_ABORT) will be enumerated,
  which is set to indicate to updated software that the loaded microcode is
  forcing RTM abort.
* On processors that enumerate support for RTM, the CPUID enumeration bits
  for Intel TSX (CPUID.07H.0H.EBX[11] and CPUID.07H.0H.EBX[4]) continue to
  be set by default after microcode update.
* Workloads that were benefited from Intel TSX might experience a change
  in performance.
* System software may use a new bit in Model-Specific Register (MSR) 0x10F
  TSX_FORCE_ABORT[TSX_CPUID_CLEAR] functionality to clear the Hardware Lock
  Elision (HLE) and RTM bits to indicate to software that Intel TSX is
  disabled.

1. Add RTM_ALWAYS_ABORT to CPUID features.
2. Set RTM usable only if RTM_ALWAYS_ABORT isn't set.  This skips the
string/tst-memchr-rtm etc. testcases on the affected processors, which
always fail after a microcde update.
3. Check RTM feature, instead of usability, against /proc/cpuinfo.

This fixes BZ #28033.
Diffstat (limited to 'sysdeps/x86/include')
-rw-r--r--sysdeps/x86/include/cpu-features.h6
1 files changed, 3 insertions, 3 deletions
diff --git a/sysdeps/x86/include/cpu-features.h b/sysdeps/x86/include/cpu-features.h
index 4f1c4ee402..59e01df543 100644
--- a/sysdeps/x86/include/cpu-features.h
+++ b/sysdeps/x86/include/cpu-features.h
@@ -229,7 +229,7 @@ enum
 #define bit_cpu_AVX512_VP2INTERSECT (1u << 8)
 #define bit_cpu_INDEX_7_EDX_9	(1u << 9)
 #define bit_cpu_MD_CLEAR	(1u << 10)
-#define bit_cpu_INDEX_7_EDX_11	(1u << 11)
+#define bit_cpu_RTM_ALWAYS_ABORT (1u << 11)
 #define bit_cpu_INDEX_7_EDX_12	(1u << 12)
 #define bit_cpu_INDEX_7_EDX_13	(1u << 13)
 #define bit_cpu_SERIALIZE	(1u << 14)
@@ -463,7 +463,7 @@ enum
 #define index_cpu_AVX512_VP2INTERSECT CPUID_INDEX_7
 #define index_cpu_INDEX_7_EDX_9	CPUID_INDEX_7
 #define index_cpu_MD_CLEAR	CPUID_INDEX_7
-#define index_cpu_INDEX_7_EDX_11 CPUID_INDEX_7
+#define index_cpu_RTM_ALWAYS_ABORT CPUID_INDEX_7
 #define index_cpu_INDEX_7_EDX_12 CPUID_INDEX_7
 #define index_cpu_INDEX_7_EDX_13 CPUID_INDEX_7
 #define index_cpu_SERIALIZE	CPUID_INDEX_7
@@ -697,7 +697,7 @@ enum
 #define reg_AVX512_VP2INTERSECT	edx
 #define reg_INDEX_7_EDX_9	edx
 #define reg_MD_CLEAR		edx
-#define reg_INDEX_7_EDX_11	edx
+#define reg_RTM_ALWAYS_ABORT	edx
 #define reg_INDEX_7_EDX_12	edx
 #define reg_INDEX_7_EDX_13	edx
 #define reg_SERIALIZE		edx