From ea8e465a6b8d0f26c72bcbe453a854de3abf68ec Mon Sep 17 00:00:00 2001 From: "H.J. Lu" Date: Wed, 30 Jun 2021 10:47:06 -0700 Subject: [PATCH] x86: Check RTM_ALWAYS_ABORT for RTM [BZ #28033] Content-type: text/plain; charset=UTF-8 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. --- manual/platform.texi | 3 +++ sysdeps/x86/cpu-features.c | 5 ++++- sysdeps/x86/sys/platform/x86.h | 6 +++--- sysdeps/x86/tst-cpu-features-supports.c | 2 +- sysdeps/x86/tst-get-cpu-features.c | 2 ++ 5 files changed, 13 insertions(+), 5 deletions(-) Conflicts: sysdeps/x86/bits/platform/x86.h (doesn't exist) sysdeps/x86/bits/platform/x86.h (account for lack of upstream renames) diff --git a/manual/platform.texi b/manual/platform.texi index 8fec2933..b7e8aef7 100644 --- a/manual/platform.texi +++ b/manual/platform.texi @@ -510,6 +510,9 @@ capability. @item @code{RTM} -- RTM instruction extensions. +@item +@code{RTM_ALWAYS_ABORT} -- Transactions always abort, making RTM unusable. + @item @code{SDBG} -- IA32_DEBUG_INTERFACE MSR for silicon debug. diff --git a/sysdeps/x86/cpu-features.c b/sysdeps/x86/cpu-features.c index 3610ee5c..4889f062 100644 --- a/sysdeps/x86/cpu-features.c +++ b/sysdeps/x86/cpu-features.c @@ -74,7 +74,6 @@ update_usable (struct cpu_features *cpu_features) CPU_FEATURE_SET_USABLE (cpu_features, HLE); CPU_FEATURE_SET_USABLE (cpu_features, BMI2); CPU_FEATURE_SET_USABLE (cpu_features, ERMS); - CPU_FEATURE_SET_USABLE (cpu_features, RTM); CPU_FEATURE_SET_USABLE (cpu_features, RDSEED); CPU_FEATURE_SET_USABLE (cpu_features, ADX); CPU_FEATURE_SET_USABLE (cpu_features, CLFLUSHOPT); @@ -90,6 +89,7 @@ update_usable (struct cpu_features *cpu_features) CPU_FEATURE_SET_USABLE (cpu_features, MOVDIRI); CPU_FEATURE_SET_USABLE (cpu_features, MOVDIR64B); CPU_FEATURE_SET_USABLE (cpu_features, FSRM); + CPU_FEATURE_SET_USABLE (cpu_features, RTM_ALWAYS_ABORT); CPU_FEATURE_SET_USABLE (cpu_features, SERIALIZE); CPU_FEATURE_SET_USABLE (cpu_features, TSXLDTRK); CPU_FEATURE_SET_USABLE (cpu_features, LAHF64_SAHF64); @@ -779,6 +779,9 @@ no_cpuid: GLRO(dl_platform) = "i586"; #endif + if (!CPU_FEATURES_CPU_P (cpu_features, RTM_ALWAYS_ABORT)) + CPU_FEATURE_SET_USABLE (cpu_features, RTM); + #if CET_ENABLED # if HAVE_TUNABLES TUNABLE_GET (x86_ibt, tunable_val_t *, diff --git a/sysdeps/x86/sys/platform/x86.h b/sysdeps/x86/sys/platform/x86.h index e5cc7c68..7a434926 100644 --- a/sysdeps/x86/sys/platform/x86.h +++ b/sysdeps/x86/sys/platform/x86.h @@ -247,7 +247,7 @@ extern const struct cpu_features *__x86_get_cpu_features (unsigned int) #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) @@ -471,7 +471,7 @@ extern const struct cpu_features *__x86_get_cpu_features (unsigned int) #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 @@ -695,7 +695,7 @@ extern const struct cpu_features *__x86_get_cpu_features (unsigned int) #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-cpu-features-supports.c b/sysdeps/x86/tst-cpu-features-supports.c index 287cf01f..8100a319 100644 --- a/sysdeps/x86/tst-cpu-features-supports.c +++ b/sysdeps/x86/tst-cpu-features-supports.c @@ -152,7 +152,7 @@ do_test (int argc, char **argv) fails += CHECK_SUPPORTS (rdpid, RDPID); fails += CHECK_SUPPORTS (rdrnd, RDRAND); fails += CHECK_SUPPORTS (rdseed, RDSEED); - fails += CHECK_SUPPORTS (rtm, RTM); + fails += CHECK_CPU_SUPPORTS (rtm, RTM); fails += CHECK_SUPPORTS (serialize, SERIALIZE); fails += CHECK_SUPPORTS (sha, SHA); fails += CHECK_CPU_SUPPORTS (shstk, SHSTK); diff --git a/sysdeps/x86/tst-get-cpu-features.c b/sysdeps/x86/tst-get-cpu-features.c index 2763deb6..0717e5d8 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 (UINTR); 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); @@ -344,6 +345,7 @@ 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); -- GitLab