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From: Raoni Fassina Firmino <raoni@sourceware.org> To: glibc-cvs@sourceware.org Subject: [glibc/ibm/2.32/master] x86: Check RTM_ALWAYS_ABORT for RTM [BZ #28033] Date: Fri, 1 Apr 2022 20:07:45 +0000 (GMT) [thread overview] Message-ID: <20220401200745.C74513839820@sourceware.org> (raw) https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=77317b3b0df3170575e135be01e9554261c43b8a commit 77317b3b0df3170575e135be01e9554261c43b8a Author: H.J. Lu <hjl.tools@gmail.com> Date: Wed Jun 30 10:47:06 2021 -0700 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. (cherry picked from commit ea8e465a6b8d0f26c72bcbe453a854de3abf68ec) Diff: --- sysdeps/x86/cpu-features.c | 4 +++- sysdeps/x86/cpu-features.h | 6 +++--- sysdeps/x86/tst-get-cpu-features.c | 2 ++ 3 files changed, 8 insertions(+), 4 deletions(-) diff --git a/sysdeps/x86/cpu-features.c b/sysdeps/x86/cpu-features.c index eb554b6d14..ad135a122b 100644 --- a/sysdeps/x86/cpu-features.c +++ b/sysdeps/x86/cpu-features.c @@ -71,7 +71,6 @@ update_usable (struct cpu_features *cpu_features) CPU_FEATURE_UNSET (cpu_features, INDEX_7_EDX_6); CPU_FEATURE_UNSET (cpu_features, INDEX_7_EDX_7); CPU_FEATURE_UNSET (cpu_features, INDEX_7_EDX_9); - CPU_FEATURE_UNSET (cpu_features, INDEX_7_EDX_11); CPU_FEATURE_UNSET (cpu_features, INDEX_7_EDX_12); CPU_FEATURE_UNSET (cpu_features, INDEX_7_EDX_13); CPU_FEATURE_UNSET (cpu_features, INDEX_7_EDX_17); @@ -318,6 +317,9 @@ update_usable (struct cpu_features *cpu_features) /* Determine if PKU is usable. */ if (CPU_FEATURES_CPU_P (cpu_features, OSPKE)) CPU_FEATURE_SET (cpu_features, PKU); + + if (CPU_FEATURES_CPU_P (cpu_features, RTM_ALWAYS_ABORT)) + CPU_FEATURE_UNSET (cpu_features, RTM); } static void diff --git a/sysdeps/x86/cpu-features.h b/sysdeps/x86/cpu-features.h index 72ea74d083..8995a15f09 100644 --- a/sysdeps/x86/cpu-features.h +++ b/sysdeps/x86/cpu-features.h @@ -295,7 +295,7 @@ extern const struct cpu_features *__get_cpu_features (void) #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) @@ -508,7 +508,7 @@ extern const struct cpu_features *__get_cpu_features (void) #define index_cpu_AVX512_VP2INTERSECT COMMON_CPUID_INDEX_7 #define index_cpu_INDEX_7_EDX_9 COMMON_CPUID_INDEX_7 #define index_cpu_MD_CLEAR COMMON_CPUID_INDEX_7 -#define index_cpu_INDEX_7_EDX_11 COMMON_CPUID_INDEX_7 +#define index_cpu_RTM_ALWAYS_ABORT COMMON_CPUID_INDEX_7 #define index_cpu_INDEX_7_EDX_12 COMMON_CPUID_INDEX_7 #define index_cpu_INDEX_7_EDX_13 COMMON_CPUID_INDEX_7 #define index_cpu_SERIALIZE COMMON_CPUID_INDEX_7 @@ -721,7 +721,7 @@ extern const struct cpu_features *__get_cpu_features (void) #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 diff --git a/sysdeps/x86/tst-get-cpu-features.c b/sysdeps/x86/tst-get-cpu-features.c index 080c58e70b..527de3b5d9 100644 --- a/sysdeps/x86/tst-get-cpu-features.c +++ b/sysdeps/x86/tst-get-cpu-features.c @@ -183,6 +183,7 @@ do_test (void) CHECK_CPU_FEATURE (FSRM); CHECK_CPU_FEATURE (AVX512_VP2INTERSECT); CHECK_CPU_FEATURE (MD_CLEAR); + CHECK_CPU_FEATURE (RTM_ALWAYS_ABORT); CHECK_CPU_FEATURE (SERIALIZE); CHECK_CPU_FEATURE (HYBRID); CHECK_CPU_FEATURE (TSXLDTRK); @@ -336,6 +337,7 @@ do_test (void) CHECK_CPU_FEATURE_USABLE (FSRM); CHECK_CPU_FEATURE_USABLE (AVX512_VP2INTERSECT); CHECK_CPU_FEATURE_USABLE (MD_CLEAR); + CHECK_CPU_FEATURE_USABLE (RTM_ALWAYS_ABORT); CHECK_CPU_FEATURE_USABLE (SERIALIZE); CHECK_CPU_FEATURE_USABLE (HYBRID); CHECK_CPU_FEATURE_USABLE (TSXLDTRK);
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