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40548c6b6c
Pull x86 pti updates from Thomas Gleixner: "This contains: - a PTI bugfix to avoid setting reserved CR3 bits when PCID is disabled. This seems to cause issues on a virtual machine at least and is incorrect according to the AMD manual. - a PTI bugfix which disables the perf BTS facility if PTI is enabled. The BTS AUX buffer is not globally visible and causes the CPU to fault when the mapping disappears on switching CR3 to user space. A full fix which restores BTS on PTI is non trivial and will be worked on. - PTI bugfixes for EFI and trusted boot which make sure that the user space visible page table entries have the NX bit cleared - removal of dead code in the PTI pagetable setup functions - add PTI documentation - add a selftest for vsyscall to verify that the kernel actually implements what it advertises. - a sysfs interface to expose vulnerability and mitigation information so there is a coherent way for users to retrieve the status. - the initial spectre_v2 mitigations, aka retpoline: + The necessary ASM thunk and compiler support + The ASM variants of retpoline and the conversion of affected ASM code + Make LFENCE serializing on AMD so it can be used as speculation trap + The RSB fill after vmexit - initial objtool support for retpoline As I said in the status mail this is the most of the set of patches which should go into 4.15 except two straight forward patches still on hold: - the retpoline add on of LFENCE which waits for ACKs - the RSB fill after context switch Both should be ready to go early next week and with that we'll have covered the major holes of spectre_v2 and go back to normality" * 'x86-pti-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (28 commits) x86,perf: Disable intel_bts when PTI security/Kconfig: Correct the Documentation reference for PTI x86/pti: Fix !PCID and sanitize defines selftests/x86: Add test_vsyscall x86/retpoline: Fill return stack buffer on vmexit x86/retpoline/irq32: Convert assembler indirect jumps x86/retpoline/checksum32: Convert assembler indirect jumps x86/retpoline/xen: Convert Xen hypercall indirect jumps x86/retpoline/hyperv: Convert assembler indirect jumps x86/retpoline/ftrace: Convert ftrace assembler indirect jumps x86/retpoline/entry: Convert entry assembler indirect jumps x86/retpoline/crypto: Convert crypto assembler indirect jumps x86/spectre: Add boot time option to select Spectre v2 mitigation x86/retpoline: Add initial retpoline support objtool: Allow alternatives to be ignored objtool: Detect jumps to retpoline thunks x86/pti: Make unpoison of pgd for trusted boot work for real x86/alternatives: Fix optimize_nops() checking sysfs/cpu: Fix typos in vulnerability documentation x86/cpu/AMD: Use LFENCE_RDTSC in preference to MFENCE_RDTSC ...
394 lines
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394 lines
15 KiB
Plaintext
What: /sys/devices/system/cpu/
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Date: pre-git history
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Contact: Linux kernel mailing list <linux-kernel@vger.kernel.org>
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Description:
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A collection of both global and individual CPU attributes
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Individual CPU attributes are contained in subdirectories
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named by the kernel's logical CPU number, e.g.:
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/sys/devices/system/cpu/cpu#/
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What: /sys/devices/system/cpu/kernel_max
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/sys/devices/system/cpu/offline
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/sys/devices/system/cpu/online
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/sys/devices/system/cpu/possible
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/sys/devices/system/cpu/present
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Date: December 2008
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Contact: Linux kernel mailing list <linux-kernel@vger.kernel.org>
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Description: CPU topology files that describe kernel limits related to
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hotplug. Briefly:
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kernel_max: the maximum cpu index allowed by the kernel
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configuration.
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offline: cpus that are not online because they have been
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HOTPLUGGED off or exceed the limit of cpus allowed by the
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kernel configuration (kernel_max above).
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online: cpus that are online and being scheduled.
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possible: cpus that have been allocated resources and can be
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brought online if they are present.
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present: cpus that have been identified as being present in
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the system.
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See Documentation/cputopology.txt for more information.
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What: /sys/devices/system/cpu/probe
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/sys/devices/system/cpu/release
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Date: November 2009
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Contact: Linux kernel mailing list <linux-kernel@vger.kernel.org>
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Description: Dynamic addition and removal of CPU's. This is not hotplug
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removal, this is meant complete removal/addition of the CPU
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from the system.
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probe: writes to this file will dynamically add a CPU to the
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system. Information written to the file to add CPU's is
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architecture specific.
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release: writes to this file dynamically remove a CPU from
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the system. Information writtento the file to remove CPU's
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is architecture specific.
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What: /sys/devices/system/cpu/cpu#/node
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Date: October 2009
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Contact: Linux memory management mailing list <linux-mm@kvack.org>
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Description: Discover NUMA node a CPU belongs to
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When CONFIG_NUMA is enabled, a symbolic link that points
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to the corresponding NUMA node directory.
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For example, the following symlink is created for cpu42
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in NUMA node 2:
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/sys/devices/system/cpu/cpu42/node2 -> ../../node/node2
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What: /sys/devices/system/cpu/cpu#/topology/core_id
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/sys/devices/system/cpu/cpu#/topology/core_siblings
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/sys/devices/system/cpu/cpu#/topology/core_siblings_list
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/sys/devices/system/cpu/cpu#/topology/physical_package_id
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/sys/devices/system/cpu/cpu#/topology/thread_siblings
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/sys/devices/system/cpu/cpu#/topology/thread_siblings_list
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Date: December 2008
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Contact: Linux kernel mailing list <linux-kernel@vger.kernel.org>
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Description: CPU topology files that describe a logical CPU's relationship
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to other cores and threads in the same physical package.
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One cpu# directory is created per logical CPU in the system,
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e.g. /sys/devices/system/cpu/cpu42/.
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Briefly, the files above are:
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core_id: the CPU core ID of cpu#. Typically it is the
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hardware platform's identifier (rather than the kernel's).
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The actual value is architecture and platform dependent.
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core_siblings: internal kernel map of cpu#'s hardware threads
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within the same physical_package_id.
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core_siblings_list: human-readable list of the logical CPU
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numbers within the same physical_package_id as cpu#.
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physical_package_id: physical package id of cpu#. Typically
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corresponds to a physical socket number, but the actual value
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is architecture and platform dependent.
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thread_siblings: internel kernel map of cpu#'s hardware
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threads within the same core as cpu#
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thread_siblings_list: human-readable list of cpu#'s hardware
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threads within the same core as cpu#
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See Documentation/cputopology.txt for more information.
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What: /sys/devices/system/cpu/cpuidle/current_driver
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/sys/devices/system/cpu/cpuidle/current_governer_ro
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Date: September 2007
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Contact: Linux kernel mailing list <linux-kernel@vger.kernel.org>
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Description: Discover cpuidle policy and mechanism
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Various CPUs today support multiple idle levels that are
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differentiated by varying exit latencies and power
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consumption during idle.
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Idle policy (governor) is differentiated from idle mechanism
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(driver)
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current_driver: displays current idle mechanism
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current_governor_ro: displays current idle policy
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See files in Documentation/cpuidle/ for more information.
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What: /sys/devices/system/cpu/cpu#/cpufreq/*
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Date: pre-git history
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Contact: linux-pm@vger.kernel.org
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Description: Discover and change clock speed of CPUs
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Clock scaling allows you to change the clock speed of the
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CPUs on the fly. This is a nice method to save battery
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power, because the lower the clock speed, the less power
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the CPU consumes.
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There are many knobs to tweak in this directory.
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See files in Documentation/cpu-freq/ for more information.
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In particular, read Documentation/cpu-freq/user-guide.txt
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to learn how to control the knobs.
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What: /sys/devices/system/cpu/cpu#/cpufreq/freqdomain_cpus
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Date: June 2013
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Contact: linux-pm@vger.kernel.org
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Description: Discover CPUs in the same CPU frequency coordination domain
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freqdomain_cpus is the list of CPUs (online+offline) that share
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the same clock/freq domain (possibly at the hardware level).
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That information may be hidden from the cpufreq core and the
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value of related_cpus may be different from freqdomain_cpus. This
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attribute is useful for user space DVFS controllers to get better
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power/performance results for platforms using acpi-cpufreq.
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This file is only present if the acpi-cpufreq driver is in use.
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What: /sys/devices/system/cpu/cpu*/cache/index3/cache_disable_{0,1}
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Date: August 2008
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KernelVersion: 2.6.27
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Contact: Linux kernel mailing list <linux-kernel@vger.kernel.org>
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Description: Disable L3 cache indices
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These files exist in every CPU's cache/index3 directory. Each
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cache_disable_{0,1} file corresponds to one disable slot which
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can be used to disable a cache index. Reading from these files
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on a processor with this functionality will return the currently
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disabled index for that node. There is one L3 structure per
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node, or per internal node on MCM machines. Writing a valid
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index to one of these files will cause the specificed cache
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index to be disabled.
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All AMD processors with L3 caches provide this functionality.
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For details, see BKDGs at
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http://developer.amd.com/documentation/guides/Pages/default.aspx
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What: /sys/devices/system/cpu/cpufreq/boost
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Date: August 2012
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Contact: Linux kernel mailing list <linux-kernel@vger.kernel.org>
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Description: Processor frequency boosting control
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This switch controls the boost setting for the whole system.
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Boosting allows the CPU and the firmware to run at a frequency
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beyound it's nominal limit.
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More details can be found in
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Documentation/admin-guide/pm/cpufreq.rst
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What: /sys/devices/system/cpu/cpu#/crash_notes
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/sys/devices/system/cpu/cpu#/crash_notes_size
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Date: April 2013
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Contact: kexec@lists.infradead.org
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Description: address and size of the percpu note.
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crash_notes: the physical address of the memory that holds the
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note of cpu#.
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crash_notes_size: size of the note of cpu#.
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What: /sys/devices/system/cpu/intel_pstate/max_perf_pct
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/sys/devices/system/cpu/intel_pstate/min_perf_pct
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/sys/devices/system/cpu/intel_pstate/no_turbo
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Date: February 2013
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Contact: linux-pm@vger.kernel.org
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Description: Parameters for the Intel P-state driver
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Logic for selecting the current P-state in Intel
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Sandybridge+ processors. The three knobs control
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limits for the P-state that will be requested by the
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driver.
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max_perf_pct: limits the maximum P state that will be requested by
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the driver stated as a percentage of the available performance.
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min_perf_pct: limits the minimum P state that will be requested by
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the driver stated as a percentage of the available performance.
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no_turbo: limits the driver to selecting P states below the turbo
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frequency range.
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More details can be found in
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Documentation/admin-guide/pm/intel_pstate.rst
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What: /sys/devices/system/cpu/cpu*/cache/index*/<set_of_attributes_mentioned_below>
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Date: July 2014(documented, existed before August 2008)
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Contact: Sudeep Holla <sudeep.holla@arm.com>
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Linux kernel mailing list <linux-kernel@vger.kernel.org>
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Description: Parameters for the CPU cache attributes
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allocation_policy:
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- WriteAllocate: allocate a memory location to a cache line
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on a cache miss because of a write
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- ReadAllocate: allocate a memory location to a cache line
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on a cache miss because of a read
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- ReadWriteAllocate: both writeallocate and readallocate
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attributes: LEGACY used only on IA64 and is same as write_policy
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coherency_line_size: the minimum amount of data in bytes that gets
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transferred from memory to cache
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level: the cache hierarchy in the multi-level cache configuration
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number_of_sets: total number of sets in the cache, a set is a
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collection of cache lines with the same cache index
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physical_line_partition: number of physical cache line per cache tag
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shared_cpu_list: the list of logical cpus sharing the cache
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shared_cpu_map: logical cpu mask containing the list of cpus sharing
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the cache
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size: the total cache size in kB
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type:
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- Instruction: cache that only holds instructions
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- Data: cache that only caches data
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- Unified: cache that holds both data and instructions
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ways_of_associativity: degree of freedom in placing a particular block
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of memory in the cache
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write_policy:
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- WriteThrough: data is written to both the cache line
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and to the block in the lower-level memory
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- WriteBack: data is written only to the cache line and
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the modified cache line is written to main
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memory only when it is replaced
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What: /sys/devices/system/cpu/cpu*/cache/index*/id
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Date: September 2016
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Contact: Linux kernel mailing list <linux-kernel@vger.kernel.org>
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Description: Cache id
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The id provides a unique number for a specific instance of
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a cache of a particular type. E.g. there may be a level
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3 unified cache on each socket in a server and we may
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assign them ids 0, 1, 2, ...
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Note that id value can be non-contiguous. E.g. level 1
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caches typically exist per core, but there may not be a
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power of two cores on a socket, so these caches may be
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numbered 0, 1, 2, 3, 4, 5, 8, 9, 10, ...
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What: /sys/devices/system/cpu/cpuX/cpufreq/throttle_stats
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/sys/devices/system/cpu/cpuX/cpufreq/throttle_stats/turbo_stat
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/sys/devices/system/cpu/cpuX/cpufreq/throttle_stats/sub_turbo_stat
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/sys/devices/system/cpu/cpuX/cpufreq/throttle_stats/unthrottle
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/sys/devices/system/cpu/cpuX/cpufreq/throttle_stats/powercap
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/sys/devices/system/cpu/cpuX/cpufreq/throttle_stats/overtemp
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/sys/devices/system/cpu/cpuX/cpufreq/throttle_stats/supply_fault
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/sys/devices/system/cpu/cpuX/cpufreq/throttle_stats/overcurrent
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/sys/devices/system/cpu/cpuX/cpufreq/throttle_stats/occ_reset
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Date: March 2016
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Contact: Linux kernel mailing list <linux-kernel@vger.kernel.org>
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Linux for PowerPC mailing list <linuxppc-dev@ozlabs.org>
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Description: POWERNV CPUFreq driver's frequency throttle stats directory and
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attributes
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'cpuX/cpufreq/throttle_stats' directory contains the CPU frequency
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throttle stat attributes for the chip. The throttle stats of a cpu
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is common across all the cpus belonging to a chip. Below are the
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throttle attributes exported in the 'throttle_stats' directory:
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- turbo_stat : This file gives the total number of times the max
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frequency is throttled to lower frequency in turbo (at and above
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nominal frequency) range of frequencies.
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- sub_turbo_stat : This file gives the total number of times the
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max frequency is throttled to lower frequency in sub-turbo(below
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nominal frequency) range of frequencies.
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- unthrottle : This file gives the total number of times the max
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frequency is unthrottled after being throttled.
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- powercap : This file gives the total number of times the max
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frequency is throttled due to 'Power Capping'.
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- overtemp : This file gives the total number of times the max
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frequency is throttled due to 'CPU Over Temperature'.
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- supply_fault : This file gives the total number of times the
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max frequency is throttled due to 'Power Supply Failure'.
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- overcurrent : This file gives the total number of times the
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max frequency is throttled due to 'Overcurrent'.
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- occ_reset : This file gives the total number of times the max
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frequency is throttled due to 'OCC Reset'.
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The sysfs attributes representing different throttle reasons like
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powercap, overtemp, supply_fault, overcurrent and occ_reset map to
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the reasons provided by OCC firmware for throttling the frequency.
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What: /sys/devices/system/cpu/cpufreq/policyX/throttle_stats
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/sys/devices/system/cpu/cpufreq/policyX/throttle_stats/turbo_stat
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/sys/devices/system/cpu/cpufreq/policyX/throttle_stats/sub_turbo_stat
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/sys/devices/system/cpu/cpufreq/policyX/throttle_stats/unthrottle
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/sys/devices/system/cpu/cpufreq/policyX/throttle_stats/powercap
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/sys/devices/system/cpu/cpufreq/policyX/throttle_stats/overtemp
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/sys/devices/system/cpu/cpufreq/policyX/throttle_stats/supply_fault
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/sys/devices/system/cpu/cpufreq/policyX/throttle_stats/overcurrent
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/sys/devices/system/cpu/cpufreq/policyX/throttle_stats/occ_reset
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Date: March 2016
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Contact: Linux kernel mailing list <linux-kernel@vger.kernel.org>
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Linux for PowerPC mailing list <linuxppc-dev@ozlabs.org>
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Description: POWERNV CPUFreq driver's frequency throttle stats directory and
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attributes
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'policyX/throttle_stats' directory and all the attributes are same as
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the /sys/devices/system/cpu/cpuX/cpufreq/throttle_stats directory and
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attributes which give the frequency throttle information of the chip.
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What: /sys/devices/system/cpu/cpuX/regs/
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/sys/devices/system/cpu/cpuX/regs/identification/
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/sys/devices/system/cpu/cpuX/regs/identification/midr_el1
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/sys/devices/system/cpu/cpuX/regs/identification/revidr_el1
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Date: June 2016
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Contact: Linux ARM Kernel Mailing list <linux-arm-kernel@lists.infradead.org>
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Description: AArch64 CPU registers
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'identification' directory exposes the CPU ID registers for
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identifying model and revision of the CPU.
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What: /sys/devices/system/cpu/cpu#/cpu_capacity
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Date: December 2016
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Contact: Linux kernel mailing list <linux-kernel@vger.kernel.org>
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Description: information about CPUs heterogeneity.
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cpu_capacity: capacity of cpu#.
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What: /sys/devices/system/cpu/vulnerabilities
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/sys/devices/system/cpu/vulnerabilities/meltdown
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/sys/devices/system/cpu/vulnerabilities/spectre_v1
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/sys/devices/system/cpu/vulnerabilities/spectre_v2
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Date: January 2018
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Contact: Linux kernel mailing list <linux-kernel@vger.kernel.org>
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Description: Information about CPU vulnerabilities
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The files are named after the code names of CPU
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vulnerabilities. The output of those files reflects the
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state of the CPUs in the system. Possible output values:
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"Not affected" CPU is not affected by the vulnerability
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"Vulnerable" CPU is affected and no mitigation in effect
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"Mitigation: $M" CPU is affected and mitigation $M is in effect
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