forked from Minki/linux
mainlining shenanigans
1348924ba8
Intel client processors that support the IA32_TSX_FORCE_ABORT MSR related to perf counter interaction [1] received a microcode update that deprecates the Transactional Synchronization Extension (TSX) feature. The bit FORCE_ABORT_RTM now defaults to 1, writes to this bit are ignored. A new bit TSX_CPUID_CLEAR clears the TSX related CPUID bits. The summary of changes to the IA32_TSX_FORCE_ABORT MSR are: Bit 0: FORCE_ABORT_RTM (legacy bit, new default=1) Status bit that indicates if RTM transactions are always aborted. This bit is essentially !SDV_ENABLE_RTM(Bit 2). Writes to this bit are ignored. Bit 1: TSX_CPUID_CLEAR (new bit, default=0) When set, CPUID.HLE = 0 and CPUID.RTM = 0. Bit 2: SDV_ENABLE_RTM (new bit, default=0) When clear, XBEGIN will always abort with EAX code 0. When set, XBEGIN will not be forced to abort (but will always abort in SGX enclaves). This bit is intended to be used on developer systems. If this bit is set, transactional atomicity correctness is not certain. SDV = Software Development Vehicle (SDV), i.e. developer systems. Performance monitoring counter 3 is usable in all cases, regardless of the value of above bits. Add support for a new CPUID bit - CPUID.RTM_ALWAYS_ABORT (CPUID 7.EDX[11]) - to indicate the status of always abort behavior. [1] [ bp: Look for document ID 604224, "Performance Monitoring Impact of Intel Transactional Synchronization Extension Memory". Since there's no way for us to have stable links to documents... ] [ bp: Massage and extend commit message. ] Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Andi Kleen <ak@linux.intel.com> Reviewed-by: Tony Luck <tony.luck@intel.com> Tested-by: Neelima Krishnan <neelima.krishnan@intel.com> Link: https://lkml.kernel.org/r/9add61915b4a4eedad74fbd869107863a28b428e.1623704845.git-series.pawan.kumar.gupta@linux.intel.com |
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drivers | ||
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include | ||
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ipc | ||
kernel | ||
lib | ||
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MAINTAINERS | ||
Makefile | ||
README |
Linux kernel ============ There are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. Please read Documentation/admin-guide/README.rst first. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. The formatted documentation can also be read online at: https://www.kernel.org/doc/html/latest/ There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.