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2025-06-17x86/bugs: Add a Transient Scheduler Attacks mitigationBorislav Petkov (AMD)
Add the required features detection glue to bugs.c et all in order to support the TSA mitigation. Co-developed-by: Kim Phillips <kim.phillips@amd.com> Signed-off-by: Kim Phillips <kim.phillips@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
2025-05-28Merge tag 'arm64-upstream' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux Pull arm64 updates from Will Deacon: "The headline feature is the re-enablement of support for Arm's Scalable Matrix Extension (SME) thanks to a bumper crop of fixes from Mark Rutland. If matrices aren't your thing, then Ryan's page-table optimisation work is much more interesting. Summary: ACPI, EFI and PSCI: - Decouple Arm's "Software Delegated Exception Interface" (SDEI) support from the ACPI GHES code so that it can be used by platforms booted with device-tree - Remove unnecessary per-CPU tracking of the FPSIMD state across EFI runtime calls - Fix a node refcount imbalance in the PSCI device-tree code CPU Features: - Ensure register sanitisation is applied to fields in ID_AA64MMFR4 - Expose AIDR_EL1 to userspace via sysfs, primarily so that KVM guests can reliably query the underlying CPU types from the VMM - Re-enabling of SME support (CONFIG_ARM64_SME) as a result of fixes to our context-switching, signal handling and ptrace code Entry code: - Hook up TIF_NEED_RESCHED_LAZY so that CONFIG_PREEMPT_LAZY can be selected Memory management: - Prevent BSS exports from being used by the early PI code - Propagate level and stride information to the low-level TLB invalidation routines when operating on hugetlb entries - Use the page-table contiguous hint for vmap() mappings with VM_ALLOW_HUGE_VMAP where possible - Optimise vmalloc()/vmap() page-table updates to use "lazy MMU mode" and hook this up on arm64 so that the trailing DSB (used to publish the updates to the hardware walker) can be deferred until the end of the mapping operation - Extend mmap() randomisation for 52-bit virtual addresses (on par with 48-bit addressing) and remove limited support for randomisation of the linear map Perf and PMUs: - Add support for probing the CMN-S3 driver using ACPI - Minor driver fixes to the CMN, Arm-NI and amlogic PMU drivers Selftests: - Fix FPSIMD and SME tests to align with the freshly re-enabled SME support - Fix default setting of the OUTPUT variable so that tests are installed in the right location vDSO: - Replace raw counter access from inline assembly code with a call to the the __arch_counter_get_cntvct() helper function Miscellaneous: - Add some missing header inclusions to the CCA headers - Rework rendering of /proc/cpuinfo to follow the x86-approach and avoid repeated buffer expansion (the user-visible format remains identical) - Remove redundant selection of CONFIG_CRC32 - Extend early error message when failing to map the device-tree blob" * tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (83 commits) arm64: cputype: Add cputype definition for HIP12 arm64: el2_setup.h: Make __init_el2_fgt labels consistent, again perf/arm-cmn: Add CMN S3 ACPI binding arm64/boot: Disallow BSS exports to startup code arm64/boot: Move global CPU override variables out of BSS arm64/boot: Move init_pgdir[] and init_idmap_pgdir[] into __pi_ namespace perf/arm-cmn: Initialise cmn->cpu earlier kselftest/arm64: Set default OUTPUT path when undefined arm64: Update comment regarding values in __boot_cpu_mode arm64: mm: Drop redundant check in pmd_trans_huge() arm64/mm: Re-organise setting up FEAT_S1PIE registers PIRE0_EL1 and PIR_EL1 arm64/mm: Permit lazy_mmu_mode to be nested arm64/mm: Disable barrier batching in interrupt contexts arm64/cpuinfo: only show one cpu's info in c_show() arm64/mm: Batch barriers when updating kernel mappings mm/vmalloc: Enter lazy mmu mode while manipulating vmalloc ptes arm64/mm: Support huge pte-mapped pages in vmap mm/vmalloc: Gracefully unmap huge ptes mm/vmalloc: Warn on improper use of vunmap_range() arm64/mm: Hoist barriers out of set_ptes_anysz() loop ...
2025-05-27Merge tag 'pm-6.16-rc1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm Pull power management updates from Rafael Wysocki: "Once again, the changes are dominated by cpufreq updates, but this time the majority of them are cpufreq core changes, mostly related to the introduction of policy locking guards and __free() usage, and fixes related to boost handling. Still, there is also a significant update of the intel_pstate driver making it register an energy model when running on a hybrid platform which is used for enabling energy-aware scheduling (EAS) if the driver operates in the passive mode (and schedutil is used as the cpufreq governor for all CPUs which is the passive mode default). There are some amd-pstate driver updates too, for a good measure, including the "Requested CPU Min frequency" BIOS option support and new online/offline callbacks. In the cpuidle space, the most significant change is the addition of a C1 demotion on/off sysfs knob to intel_idle which should help some users to configure their systems more precisely. There is also the conversion of the PSCI cpuidle driver to a faux device one and there are two small updates of cpuidle governors. Device power management is also modified quite a bit, especially the handling of devices with asynchronous suspend and resume enabled during system transitions. They are now going to be handled more asynchronously during suspend transitions and somewhat less aggressively during resume transitions. Apart from the above, the operating performance points (OPP) library is now going to use mutex locking guards and scope-based cleanup helpers and there is the usual bunch of assorted fixes and code cleanups. Specifics: - Fix potential division-by-zero error in em_compute_costs() (Yaxiong Tian) - Fix typos in energy model documentation and example driver code (Moon Hee Lee, Atul Kumar Pant) - Rearrange the energy model management code and add a new function for adjusting a CPU energy model after adjusting the capacity of the given CPU to it (Rafael Wysocki) - Refactor cpufreq_online(), add and use cpufreq policy locking guards, use __free() in policy reference counting, and clean up core cpufreq code on top of that (Rafael Wysocki) - Fix boost handling on CPU suspend/resume and sysfs updates (Viresh Kumar) - Fix des_perf clamping with max_perf in amd_pstate_update() (Dhananjay Ugwekar) - Add offline, online and suspend callbacks to the amd-pstate driver, rename and use the existing amd_pstate_epp callbacks in it (Dhananjay Ugwekar) - Add support for the "Requested CPU Min frequency" BIOS option to the amd-pstate driver (Dhananjay Ugwekar) - Reset amd-pstate driver mode after running selftests (Swapnil Sapkal) - Avoid shadowing ret in amd_pstate_ut_check_driver() (Nathan Chancellor) - Add helper for governor checks to the schedutil cpufreq governor and move cpufreq-specific EAS checks to cpufreq (Rafael Wysocki) - Populate the cpu_capacity sysfs entries from the intel_pstate driver after registering asym capacity support (Ricardo Neri) - Add support for enabling Energy-aware scheduling (EAS) to the intel_pstate driver when operating in the passive mode on a hybrid platform (Rafael Wysocki) - Drop redundant cpus_read_lock() from store_local_boost() in the cpufreq core (Seyediman Seyedarab) - Replace sscanf() with kstrtouint() in the cpufreq code and use a symbol instead of a raw number in it (Bowen Yu) - Add support for autonomous CPU performance state selection to the CPPC cpufreq driver (Lifeng Zheng) - OPP: Add dev_pm_opp_set_level() (Praveen Talari) - Introduce scope-based cleanup headers and mutex locking guards in OPP core (Viresh Kumar) - Switch OPP to use kmemdup_array() (Zhang Enpei) - Optimize bucket assignment when next_timer_ns equals KTIME_MAX in the menu cpuidle governor (Zhongqiu Han) - Convert the cpuidle PSCI driver to a faux device one (Sudeep Holla) - Add C1 demotion on/off sysfs knob to the intel_idle driver (Artem Bityutskiy) - Fix typos in two comments in the teo cpuidle governor (Atul Kumar Pant) - Fix denying of auto suspend in pm_suspend_timer_fn() (Charan Teja Kalla) - Move debug runtime PM attributes to runtime_attrs[] (Rafael Wysocki) - Add new devm_ functions for enabling runtime PM and runtime PM reference counting (Bence Csókás) - Remove size arguments from strscpy() calls in the hibernation core code (Thorsten Blum) - Adjust the handling of devices with asynchronous suspend enabled during system suspend and resume to start resuming them immediately after resuming their parents and to start suspending such a device immediately after suspending its first child (Rafael Wysocki) - Adjust messages printed during tasks freezing to avoid using pr_cont() (Andrew Sayers, Paul Menzel) - Clean up unnecessary usage of !! in pm_print_times_init() (Zihuan Zhang) - Add missing wakeup source attribute relax_count to sysfs and remove the space character at the end ofi the string produced by pm_show_wakelocks() (Zijun Hu) - Add configurable pm_test delay for hibernation (Zihuan Zhang) - Disable asynchronous suspend in ucsi_ccg_probe() to prevent the cypd4226 device on Tegra boards from suspending prematurely (Jon Hunter) - Unbreak printing PM debug messages during hibernation and clean up some related code (Rafael Wysocki) - Add a systemd service to run cpupower and change cpupower binding's Makefile to use -lcpupower (John B. Wyatt IV, Francesco Poli)" * tag 'pm-6.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (72 commits) cpufreq: CPPC: Add support for autonomous selection cpufreq: Update sscanf() to kstrtouint() cpufreq: Replace magic number OPP: switch to use kmemdup_array() PM: freezer: Rewrite restarting tasks log to remove stray *done.* PM: runtime: fix denying of auto suspend in pm_suspend_timer_fn() cpufreq: drop redundant cpus_read_lock() from store_local_boost() cpupower: do not install files to /etc/default/ cpupower: do not call systemctl at install time cpupower: do not write DESTDIR to cpupower.service PM: sleep: Introduce pm_sleep_transition_in_progress() cpufreq/amd-pstate: Avoid shadowing ret in amd_pstate_ut_check_driver() cpufreq: intel_pstate: Document hybrid processor support cpufreq: intel_pstate: EAS: Increase cost for CPUs using L3 cache cpufreq: intel_pstate: EAS support for hybrid platforms PM: EM: Introduce em_adjust_cpu_capacity() PM: EM: Move CPU capacity check to em_adjust_new_capacity() PM: EM: Documentation: Fix typos in example driver code cpufreq: Drop policy locking from cpufreq_policy_is_good_for_eas() PM: sleep: Introduce pm_suspend_in_progress() ...
2025-05-26Merge branch 'pm-cpuidle'Rafael J. Wysocki
Merge cpuidle updates for 6.16-rc1: - Optimize bucket assignment when next_timer_ns equals KTIME_MAX in the menu cpuidle governor (Zhongqiu Han). - Convert the cpuidle PSCI driver to a faux device one (Sudeep Holla). - Add C1 demotion on/off sysfs knob to the intel_idle driver (Artem Bityutskiy). - Fix typos in two comments in the teo cpuidle governor (Atul Kumar Pant). * pm-cpuidle: cpuidle: psci: Avoid initializing faux device if no DT idle states are present Documentation: ABI: testing: document the new cpuidle sysfs file Documentation: admin-guide: pm: Document intel_idle C1 demotion intel_idle: Add C1 demotion on/off sysfs knob cpuidle: psci: Transition to the faux device interface cpuidle: menu: Optimize bucket assignment when next_timer_ns equals KTIME_MAX cpuidle: teo: Fix typos in two comments
2025-05-26Merge branch 'pm-cpufreq'Rafael J. Wysocki
Merge cpufreq updates for 6.16-rc1: - Refactor cpufreq_online(), add and use cpufreq policy locking guards, use __free() in policy reference counting, and clean up core cpufreq code on top of that (Rafael Wysocki). - Fix boost handling on CPU suspend/resume and sysfs updates (Viresh Kumar). - Fix des_perf clamping with max_perf in amd_pstate_update() (Dhananjay Ugwekar). - Add offline, online and suspend callbacks to the amd-pstate driver, rename and use the existing amd_pstate_epp callbacks in it (Dhananjay Ugwekar). - Add support for the "Requested CPU Min frequency" BIOS option to the amd-pstate driver (Dhananjay Ugwekar). - Reset amd-pstate driver mode after running selftests (Swapnil Sapkal). - Add helper for governor checks to the schedutil cpufreq governor and move cpufreq-specific EAS checks to cpufreq (Rafael Wysocki). - Populate the cpu_capacity sysfs entries from the intel_pstate driver after registering asym capacity support (Ricardo Neri). - Add support for enabling Energy-aware scheduling (EAS) to the intel_pstate driver when operating in the passive mode on a hybrid platform (Rafael Wysocki). - Avoid shadowing ret in amd_pstate_ut_check_driver() (Nathan Chancellor). - Drop redundant cpus_read_lock() from store_local_boost() in the cpufreq core (Seyediman Seyedarab). - Replace sscanf() with kstrtouint() in the cpufreq code and use a symbol instead of a raw number in it (Bowen Yu). - Add support for autonomous CPU performance state selection to the CPPC cpufreq driver (Lifeng Zheng). * pm-cpufreq: (31 commits) cpufreq: CPPC: Add support for autonomous selection cpufreq: Update sscanf() to kstrtouint() cpufreq: Replace magic number cpufreq: drop redundant cpus_read_lock() from store_local_boost() cpufreq/amd-pstate: Avoid shadowing ret in amd_pstate_ut_check_driver() cpufreq: intel_pstate: Document hybrid processor support cpufreq: intel_pstate: EAS: Increase cost for CPUs using L3 cache cpufreq: intel_pstate: EAS support for hybrid platforms cpufreq: Drop policy locking from cpufreq_policy_is_good_for_eas() cpufreq: intel_pstate: Populate the cpu_capacity sysfs entries arch_topology: Relocate cpu_scale to topology.[h|c] cpufreq/sched: Move cpufreq-specific EAS checks to cpufreq cpufreq/sched: schedutil: Add helper for governor checks amd-pstate-ut: Reset amd-pstate driver mode after running selftests cpufreq/amd-pstate: Add support for the "Requested CPU Min frequency" BIOS option cpufreq/amd-pstate: Add offline, online and suspend callbacks for amd_pstate_driver cpufreq: Force sync policy boost with global boost on sysfs update cpufreq: Preserve policy's boost state after resume cpufreq: Introduce policy_set_boost() cpufreq: Don't unnecessarily call set_boost() ...
2025-05-21cpufreq: CPPC: Add support for autonomous selectionLifeng Zheng
Add sysfs interfaces for CPPC autonomous selection in the cppc_cpufreq driver. Signed-off-by: Lifeng Zheng <zhenglifeng1@huawei.com> Reviewed-by: Sumit Gupta <sumitg@nvidia.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Link: https://patch.msgid.link/20250507031941.2812701-1-zhenglifeng1@huawei.com [ rjw: Subject edits ] Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2025-05-13Merge commit 'its-for-linus-20250509-merge' into x86/core, to resolve conflictsIngo Molnar
Conflicts: Documentation/admin-guide/hw-vuln/index.rst arch/x86/include/asm/cpufeatures.h arch/x86/kernel/alternative.c arch/x86/kernel/cpu/bugs.c arch/x86/kernel/cpu/common.c drivers/base/cpu.c include/linux/cpu.h Signed-off-by: Ingo Molnar <mingo@kernel.org>
2025-05-09x86/its: Enable Indirect Target Selection mitigationPawan Gupta
Indirect Target Selection (ITS) is a bug in some pre-ADL Intel CPUs with eIBRS. It affects prediction of indirect branch and RETs in the lower half of cacheline. Due to ITS such branches may get wrongly predicted to a target of (direct or indirect) branch that is located in the upper half of the cacheline. Scope of impact =============== Guest/host isolation -------------------- When eIBRS is used for guest/host isolation, the indirect branches in the VMM may still be predicted with targets corresponding to branches in the guest. Intra-mode ---------- cBPF or other native gadgets can be used for intra-mode training and disclosure using ITS. User/kernel isolation --------------------- When eIBRS is enabled user/kernel isolation is not impacted. Indirect Branch Prediction Barrier (IBPB) ----------------------------------------- After an IBPB, indirect branches may be predicted with targets corresponding to direct branches which were executed prior to IBPB. This is mitigated by a microcode update. Add cmdline parameter indirect_target_selection=off|on|force to control the mitigation to relocate the affected branches to an ITS-safe thunk i.e. located in the upper half of cacheline. Also add the sysfs reporting. When retpoline mitigation is deployed, ITS safe-thunks are not needed, because retpoline sequence is already ITS-safe. Similarly, when call depth tracking (CDT) mitigation is deployed (retbleed=stuff), ITS safe return thunk is not used, as CDT prevents RSB-underflow. To not overcomplicate things, ITS mitigation is not supported with spectre-v2 lfence;jmp mitigation. Moreover, it is less practical to deploy lfence;jmp mitigation on ITS affected parts anyways. Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com> Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Reviewed-by: Josh Poimboeuf <jpoimboe@kernel.org> Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
2025-04-29arm64: Expose AIDR_EL1 via sysfsOliver Upton
The KVM PV ABI recently added a feature that allows the VM to discover the set of physical CPU implementations, identified by a tuple of {MIDR_EL1, REVIDR_EL1, AIDR_EL1}. Unlike other KVM PV features, the expectation is that the VMM implements the hypercall instead of KVM as it has the authoritative view of where the VM gets scheduled. To do this the VMM needs to know the values of these registers on any CPU in the system. While MIDR_EL1 and REVIDR_EL1 are already exposed, AIDR_EL1 is not. Provide it in sysfs along with the other identification registers. Signed-off-by: Oliver Upton <oliver.upton@linux.dev> Reviewed-by: Cornelia Huck <cohuck@redhat.com> Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com> Link: https://lore.kernel.org/r/20250403231626.3181116-1-oliver.upton@linux.dev Signed-off-by: Will Deacon <will@kernel.org>
2025-04-22x86/cpu: Help users notice when running old Intel microcodeDave Hansen
Old microcode is bad for users and for kernel developers. For users, it exposes them to known fixed security and/or functional issues. These obviously rarely result in instant dumpster fires in every environment. But it is as important to keep your microcode up to date as it is to keep your kernel up to date. Old microcode also makes kernels harder to debug. A developer looking at an oops need to consider kernel bugs, known CPU issues and unknown CPU issues as possible causes. If they know the microcode is up to date, they can mostly eliminate known CPU issues as the cause. Make it easier to tell if CPU microcode is out of date. Add a list of released microcode. If the loaded microcode is older than the release, tell users in a place that folks can find it: /sys/devices/system/cpu/vulnerabilities/old_microcode Tell kernel kernel developers about it with the existing taint flag: TAINT_CPU_OUT_OF_SPEC == Discussion == When a user reports a potential kernel issue, it is very common to ask them to reproduce the issue on mainline. Running mainline, they will (independently from the distro) acquire a more up-to-date microcode version list. If their microcode is old, they will get a warning about the taint and kernel developers can take that into consideration when debugging. Just like any other entry in "vulnerabilities/", users are free to make their own assessment of their exposure. == Microcode Revision Discussion == The microcode versions in the table were generated from the Intel microcode git repo: 8ac9378a8487 ("microcode-20241112 Release") which as of this writing lags behind the latest microcode-20250211. It can be argued that the versions that the kernel picks to call "old" should be a revision or two old. Which specific version is picked is less important to me than picking *a* version and enforcing it. This repository contains only microcode versions that Intel has deemed to be OS-loadable. It is quite possible that the BIOS has loaded a newer microcode than the latest in this repo. If this happens, the system is considered to have new microcode, not old. Specifically, the sysfs file and taint flag answer the question: Is the CPU running on the latest OS-loadable microcode, or something even later that the BIOS loaded? In other words, Intel never publishes an authoritative list of CPUs and latest microcode revisions. Until it does, this is the best that Linux can do. Also note that the "intel-ucode-defs.h" file is simple, ugly and has lots of magic numbers. That's on purpose and should allow a single file to be shared across lots of stable kernel regardless of if they have the new "VFM" infrastructure or not. It was generated with a dumb script. == FAQ == Q: Does this tell me if my system is secure or insecure? A: No. It only tells you if your microcode was old when the system booted. Q: Should the kernel warn if the microcode list itself is too old? A: No. New kernels will get new microcode lists, both mainline and stable. The only way to have an old list is to be running an old kernel in which case you have bigger problems. Q: Is this for security or functional issues? A: Both. Q: If a given microcode update only has functional problems but no security issues, will it be considered old? A: Yes. All microcode image versions within a microcode release are treated identically. Intel appears to make security updates without disclosing them in the release notes. Thus, all updates are considered to be security-relevant. Q: Who runs old microcode? A: Anybody with an old distro. This happens all the time inside of Intel where there are lots of weird systems in labs that might not be getting regular distro updates and might also be running rather exotic microcode images. Q: If I update my microcode after booting will it stop saying "Vulnerable"? A: No. Just like all the other vulnerabilies, you need to reboot before the kernel will reassess your vulnerability. Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: "Ahmed S. Darwish" <darwi@linutronix.de> Cc: Andrew Cooper <andrew.cooper3@citrix.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Brian Gerst <brgerst@gmail.com> Cc: John Ogness <john.ogness@linutronix.de> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Juergen Gross <jgross@suse.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: https://lore.kernel.org/all/20250421195659.CF426C07%40davehans-spike.ostc.intel.com (cherry picked from commit 9127865b15eb0a1bd05ad7efe29489c44394bdc1)
2025-04-15Documentation: ABI: testing: document the new cpuidle sysfs fileArtem Bityutskiy
Mention the new 'intel_c1_demotion' sysfs file in the "cpuidle" section and refer to "Documentation/admin-guide/pm/intel_idle.rst" for more information. Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com> Link: https://patch.msgid.link/20250317135541.1471754-4-dedekind1@gmail.com Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2024-09-01Document/kexec: generalize crash hotplug descriptionSourabh Jain
Commit 79365026f869 ("crash: add a new kexec flag for hotplug support") generalizes the crash hotplug support to allow architectures to update multiple kexec segments on CPU/Memory hotplug and not just elfcorehdr. Therefore, update the relevant kernel documentation to reflect the same. No functional change. Link: https://lkml.kernel.org/r/20240812041651.703156-1-sourabhjain@linux.ibm.com Signed-off-by: Sourabh Jain <sourabhjain@linux.ibm.com> Reviewed-by: Petr Tesarik <ptesarik@suse.com> Acked-by: Baoquan He <bhe@redhat.com> Cc: Hari Bathini <hbathini@linux.ibm.com> Cc: Petr Tesarik <petr@tesarici.cz> Cc: Sourabh Jain <sourabhjain@linux.ibm.com> Cc: Jonathan Corbet <corbet@lwn.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-08-13cpu/SMT: Enable SMT only if a core is onlineNysal Jan K.A
If a core is offline then enabling SMT should not online CPUs of this core. By enabling SMT, what is intended is either changing the SMT value from "off" to "on" or setting the SMT level (threads per core) from a lower to higher value. On PowerPC the ppc64_cpu utility can be used, among other things, to perform the following functions: ppc64_cpu --cores-on # Get the number of online cores ppc64_cpu --cores-on=X # Put exactly X cores online ppc64_cpu --offline-cores=X[,Y,...] # Put specified cores offline ppc64_cpu --smt={on|off|value} # Enable, disable or change SMT level If the user has decided to offline certain cores, enabling SMT should not online CPUs in those cores. This patch fixes the issue and changes the behaviour as described, by introducing an arch specific function topology_is_core_online(). It is currently implemented only for PowerPC. Fixes: 73c58e7e1412 ("powerpc: Add HOTPLUG_SMT support") Reported-by: Tyrel Datwyler <tyreld@linux.ibm.com> Closes: https://groups.google.com/g/powerpc-utils-devel/c/wrwVzAAnRlI/m/5KJSoqP4BAAJ Signed-off-by: Nysal Jan K.A <nysal@linux.ibm.com> Reviewed-by: Shrikanth Hegde <sshegde@linux.ibm.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://msgid.link/20240731030126.956210-2-nysal@linux.ibm.com
2024-07-16Merge tag 'x86_sev_for_v6.11_rc1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 SEV updates from Borislav Petkov: - Add support for running the kernel in a SEV-SNP guest, over a Secure VM Service Module (SVSM). When running over a SVSM, different services can run at different protection levels, apart from the guest OS but still within the secure SNP environment. They can provide services to the guest, like a vTPM, for example. This series adds the required facilities to interface with such a SVSM module. - The usual fixlets, refactoring and cleanups [ And as always: "SEV" is AMD's "Secure Encrypted Virtualization". I can't be the only one who gets all the newer x86 TLA's confused, can I? - Linus ] * tag 'x86_sev_for_v6.11_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: Documentation/ABI/configfs-tsm: Fix an unexpected indentation silly x86/sev: Do RMP memory coverage check after max_pfn has been set x86/sev: Move SEV compilation units virt: sev-guest: Mark driver struct with __refdata to prevent section mismatch x86/sev: Allow non-VMPL0 execution when an SVSM is present x86/sev: Extend the config-fs attestation support for an SVSM x86/sev: Take advantage of configfs visibility support in TSM fs/configfs: Add a callback to determine attribute visibility sev-guest: configfs-tsm: Allow the privlevel_floor attribute to be updated virt: sev-guest: Choose the VMPCK key based on executing VMPL x86/sev: Provide guest VMPL level to userspace x86/sev: Provide SVSM discovery support x86/sev: Use the SVSM to create a vCPU when not in VMPL0 x86/sev: Perform PVALIDATE using the SVSM when not at VMPL0 x86/sev: Use kernel provided SVSM Calling Areas x86/sev: Check for the presence of an SVSM in the SNP secrets page x86/irqflags: Provide native versions of the local_irq_save()/restore()
2024-06-28cpumask: Add enabled cpumask for present CPUs that can be brought onlineJames Morse
The 'offline' file in sysfs shows all offline CPUs, including those that aren't present. User-space is expected to remove not-present CPUs from this list to learn which CPUs could be brought online. CPUs can be present but not-enabled. These CPUs can't be brought online until the firmware policy changes, which comes with an ACPI notification that will register the CPUs. With only the offline and present files, user-space is unable to determine which CPUs it can try to bring online. Add a new CPU mask that shows this based on all the registered CPUs. Signed-off-by: James Morse <james.morse@arm.com> Tested-by: Miguel Luis <miguel.luis@oracle.com> Tested-by: Vishnu Pajjuri <vishnu@os.amperecomputing.com> Tested-by: Jianyong Wu <jianyong.wu@arm.com> Acked-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk> Reviewed-by: Gavin Shan <gshan@redhat.com> Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Link: https://lore.kernel.org/r/20240529133446.28446-20-Jonathan.Cameron@huawei.com Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2024-06-17x86/sev: Provide guest VMPL level to userspaceTom Lendacky
Requesting an attestation report from userspace involves providing the VMPL level for the report. Currently any value from 0-3 is valid because Linux enforces running at VMPL0. When an SVSM is present, though, Linux will not be running at VMPL0 and only VMPL values starting at the VMPL level Linux is running at to 3 are valid. In order to allow userspace to determine the minimum VMPL value that can be supplied to an attestation report, create a sysfs entry that can be used to retrieve the current VMPL level of the kernel. [ bp: Add CONFIG_SYSFS ifdeffery. ] Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Link: https://lore.kernel.org/r/fff846da0d8d561f9fdaf297dcf8cd907545a25b.1717600736.git.thomas.lendacky@amd.com
2024-05-06Documentation: Fix the address of the linuxppc-dev mailing listStephen Rothwell
This list was moved many years ago. Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://msgid.link/20240503121012.3ba5000b@canb.auug.org.au
2024-03-11x86/rfds: Mitigate Register File Data Sampling (RFDS)Pawan Gupta
RFDS is a CPU vulnerability that may allow userspace to infer kernel stale data previously used in floating point registers, vector registers and integer registers. RFDS only affects certain Intel Atom processors. Intel released a microcode update that uses VERW instruction to clear the affected CPU buffers. Unlike MDS, none of the affected cores support SMT. Add RFDS bug infrastructure and enable the VERW based mitigation by default, that clears the affected buffers just before exiting to userspace. Also add sysfs reporting and cmdline parameter "reg_file_data_sampling" to control the mitigation. For details see: Documentation/admin-guide/hw-vuln/reg-file-data-sampling.rst Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com> Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
2023-09-11Documentation: Drop or replace remaining mentions of IA64Ard Biesheuvel
Drop or update mentions of IA64, as appropriate. Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2023-08-29Merge tag 'mm-nonmm-stable-2023-08-28-22-48' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Pull non-MM updates from Andrew Morton: - An extensive rework of kexec and crash Kconfig from Eric DeVolder ("refactor Kconfig to consolidate KEXEC and CRASH options") - kernel.h slimming work from Andy Shevchenko ("kernel.h: Split out a couple of macros to args.h") - gdb feature work from Kuan-Ying Lee ("Add GDB memory helper commands") - vsprintf inclusion rationalization from Andy Shevchenko ("lib/vsprintf: Rework header inclusions") - Switch the handling of kdump from a udev scheme to in-kernel handling, by Eric DeVolder ("crash: Kernel handling of CPU and memory hot un/plug") - Many singleton patches to various parts of the tree * tag 'mm-nonmm-stable-2023-08-28-22-48' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (81 commits) document while_each_thread(), change first_tid() to use for_each_thread() drivers/char/mem.c: shrink character device's devlist[] array x86/crash: optimize CPU changes crash: change crash_prepare_elf64_headers() to for_each_possible_cpu() crash: hotplug support for kexec_load() x86/crash: add x86 crash hotplug support crash: memory and CPU hotplug sysfs attributes kexec: exclude elfcorehdr from the segment digest crash: add generic infrastructure for crash hotplug support crash: move a few code bits to setup support of crash hotplug kstrtox: consistently use _tolower() kill do_each_thread() nilfs2: fix WARNING in mark_buffer_dirty due to discarded buffer reuse scripts/bloat-o-meter: count weak symbol sizes treewide: drop CONFIG_EMBEDDED lockdep: fix static memory detection even more lib/vsprintf: declare no_hash_pointers in sprintf.h lib/vsprintf: split out sprintf() and friends kernel/fork: stop playing lockless games for exe_file replacement adfs: delete unused "union adfs_dirtail" definition ...
2023-08-28Merge tag 'smp-core-2023-08-28' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull CPU hotplug updates from Thomas Gleixner: "Updates for the CPU hotplug core: - Support partial SMT enablement. So far the sysfs SMT control only allows to toggle between SMT on and off. That's sufficient for x86 which usually has at max two threads except for the Xeon PHI platform which has four threads per core Though PowerPC has up to 16 threads per core and so far it's only possible to control the number of enabled threads per core via a command line option. There is some way to control this at runtime, but that lacks enforcement and the usability is awkward This update expands the sysfs interface and the core infrastructure to accept numerical values so PowerPC can build SMT runtime control for partial SMT enablement on top The core support has also been provided to the PowerPC maintainers who added the PowerPC related changes on top - Minor cleanups and documentation updates" * tag 'smp-core-2023-08-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: Documentation: core-api/cpuhotplug: Fix state names cpu/hotplug: Remove unused function declaration cpu_set_state_online() cpu/SMT: Fix cpu_smt_possible() comment cpu/SMT: Allow enabling partial SMT states via sysfs cpu/SMT: Create topology_smt_thread_allowed() cpu/SMT: Remove topology_smt_supported() cpu/SMT: Store the current/max number of threads cpu/SMT: Move smt/control simple exit cases earlier cpu/SMT: Move SMT prototypes into cpu_smt.h cpu/hotplug: Remove dependancy against cpu_primary_thread_mask
2023-08-24crash: memory and CPU hotplug sysfs attributesEric DeVolder
Introduce the crash_hotplug attribute for memory and CPUs for use by userspace. These attributes directly facilitate the udev rule for managing userspace re-loading of the crash kernel upon hot un/plug changes. For memory, expose the crash_hotplug attribute to the /sys/devices/system/memory directory. For example: # udevadm info --attribute-walk /sys/devices/system/memory/memory81 looking at device '/devices/system/memory/memory81': KERNEL=="memory81" SUBSYSTEM=="memory" DRIVER=="" ATTR{online}=="1" ATTR{phys_device}=="0" ATTR{phys_index}=="00000051" ATTR{removable}=="1" ATTR{state}=="online" ATTR{valid_zones}=="Movable" looking at parent device '/devices/system/memory': KERNELS=="memory" SUBSYSTEMS=="" DRIVERS=="" ATTRS{auto_online_blocks}=="offline" ATTRS{block_size_bytes}=="8000000" ATTRS{crash_hotplug}=="1" For CPUs, expose the crash_hotplug attribute to the /sys/devices/system/cpu directory. For example: # udevadm info --attribute-walk /sys/devices/system/cpu/cpu0 looking at device '/devices/system/cpu/cpu0': KERNEL=="cpu0" SUBSYSTEM=="cpu" DRIVER=="processor" ATTR{crash_notes}=="277c38600" ATTR{crash_notes_size}=="368" ATTR{online}=="1" looking at parent device '/devices/system/cpu': KERNELS=="cpu" SUBSYSTEMS=="" DRIVERS=="" ATTRS{crash_hotplug}=="1" ATTRS{isolated}=="" ATTRS{kernel_max}=="8191" ATTRS{nohz_full}==" (null)" ATTRS{offline}=="4-7" ATTRS{online}=="0-3" ATTRS{possible}=="0-7" ATTRS{present}=="0-3" With these sysfs attributes in place, it is possible to efficiently instruct the udev rule to skip crash kernel reloading for kernels configured with crash hotplug support. For example, the following is the proposed udev rule change for RHEL system 98-kexec.rules (as the first lines of the rule file): # The kernel updates the crash elfcorehdr for CPU and memory changes SUBSYSTEM=="cpu", ATTRS{crash_hotplug}=="1", GOTO="kdump_reload_end" SUBSYSTEM=="memory", ATTRS{crash_hotplug}=="1", GOTO="kdump_reload_end" When examined in the context of 98-kexec.rules, the above rules test if crash_hotplug is set, and if so, the userspace initiated unload-then-reload of the crash kernel is skipped. CPU and memory checks are separated in accordance with CONFIG_HOTPLUG_CPU and CONFIG_MEMORY_HOTPLUG kernel config options. If an architecture supports, for example, memory hotplug but not CPU hotplug, then the /sys/devices/system/memory/crash_hotplug attribute file is present, but the /sys/devices/system/cpu/crash_hotplug attribute file will NOT be present. Thus the udev rule skips userspace processing of memory hot un/plug events, but the udev rule will evaluate false for CPU events, thus allowing userspace to process CPU hot un/plug events (ie the unload-then-reload of the kdump capture kernel). Link: https://lkml.kernel.org/r/20230814214446.6659-5-eric.devolder@oracle.com Signed-off-by: Eric DeVolder <eric.devolder@oracle.com> Reviewed-by: Sourabh Jain <sourabhjain@linux.ibm.com> Acked-by: Hari Bathini <hbathini@linux.ibm.com> Acked-by: Baoquan He <bhe@redhat.com> Cc: Akhil Raj <lf32.dev@gmail.com> Cc: Bjorn Helgaas <bhelgaas@google.com> Cc: Borislav Petkov (AMD) <bp@alien8.de> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Dave Young <dyoung@redhat.com> Cc: David Hildenbrand <david@redhat.com> Cc: Eric W. Biederman <ebiederm@xmission.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Mimi Zohar <zohar@linux.ibm.com> Cc: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: "Rafael J. Wysocki" <rafael@kernel.org> Cc: Sean Christopherson <seanjc@google.com> Cc: Takashi Iwai <tiwai@suse.de> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Thomas Weißschuh <linux@weissschuh.net> Cc: Valentin Schneider <vschneid@redhat.com> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-07-28cpu/SMT: Allow enabling partial SMT states via sysfsMichael Ellerman
Add support to the /sys/devices/system/cpu/smt/control interface for enabling a specified number of SMT threads per core, including partial SMT states where not all threads are brought online. The current interface accepts "on" and "off", to enable either 1 or all SMT threads per core. This commit allows writing an integer, between 1 and the number of SMT threads supported by the machine. Writing 1 is a synonym for "off", 2 or more enables SMT with the specified number of threads. When reading the file, if all threads are online "on" is returned, to avoid changing behaviour for existing users. If some other number of threads is online then the integer value is returned. Architectures like x86 only supporting 1 thread or all threads, should not define CONFIG_SMT_NUM_THREADS_DYNAMIC. Architecture supporting partial SMT states, like PowerPC, should define it. [ ldufour: Slightly reword the commit's description ] [ ldufour: Remove switch() in __store_smt_control() ] [ ldufour: Rix build issue in control_show() ] Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Laurent Dufour <ldufour@linux.ibm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Zhang Rui <rui.zhang@intel.com> Link: https://lore.kernel.org/r/20230705145143.40545-8-ldufour@linux.ibm.com
2023-07-19x86/speculation: Add Gather Data Sampling mitigationDaniel Sneddon
Gather Data Sampling (GDS) is a hardware vulnerability which allows unprivileged speculative access to data which was previously stored in vector registers. Intel processors that support AVX2 and AVX512 have gather instructions that fetch non-contiguous data elements from memory. On vulnerable hardware, when a gather instruction is transiently executed and encounters a fault, stale data from architectural or internal vector registers may get transiently stored to the destination vector register allowing an attacker to infer the stale data using typical side channel techniques like cache timing attacks. This mitigation is different from many earlier ones for two reasons. First, it is enabled by default and a bit must be set to *DISABLE* it. This is the opposite of normal mitigation polarity. This means GDS can be mitigated simply by updating microcode and leaving the new control bit alone. Second, GDS has a "lock" bit. This lock bit is there because the mitigation affects the hardware security features KeyLocker and SGX. It needs to be enabled and *STAY* enabled for these features to be mitigated against GDS. The mitigation is enabled in the microcode by default. Disable it by setting gather_data_sampling=off or by disabling all mitigations with mitigations=off. The mitigation status can be checked by reading: /sys/devices/system/cpu/vulnerabilities/gather_data_sampling Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com> Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
2023-06-21docs: arm64: Move arm64 documentation under Documentation/arch/Jonathan Corbet
Architecture-specific documentation is being moved into Documentation/arch/ as a way of cleaning up the top-level documentation directory and making the docs hierarchy more closely match the source hierarchy. Move Documentation/arm64 into arch/ (along with the Chinese equvalent translations) and fix up documentation references. Cc: Will Deacon <will@kernel.org> Cc: Alex Shi <alexs@kernel.org> Cc: Hu Haowen <src.res@email.cn> Cc: Paolo Bonzini <pbonzini@redhat.com> Acked-by: Catalin Marinas <catalin.marinas@arm.com> Reviewed-by: Yantengsi <siyanteng@loongson.cn> Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2022-10-03Merge tag 'docs-6.1' of git://git.lwn.net/linuxLinus Torvalds
Pull documentation updates from Jonathan Corbet: "There's not a huge amount of activity in the docs tree this time around, but a few significant changes even so: - A complete rewriting of the top-level index.rst file, which mostly reflects itself in a redone top page in the HTML-rendered docs. The hope is that the new organization will be a friendlier starting point for both users and developers. - Some math-rendering improvements. - A coding-style.rst update on the use of BUG() and WARN() - A big maintainer-PHP guide update. - Some code-of-conduct updates - More Chinese translation work Plus the usual pile of typo fixes, corrections, and updates" * tag 'docs-6.1' of git://git.lwn.net/linux: (66 commits) checkpatch: warn on usage of VM_BUG_ON() and other BUG variants coding-style.rst: document BUG() and WARN() rules ("do not crash the kernel") Documentation: devres: add missing IO helper Documentation: devres: update IRQ helper Documentation/mm: modify page_referenced to folio_referenced Documentation/CoC: Reflect current CoC interpretation and practices docs/doc-guide: Add documentation on SPHINX_IMGMATH docs: process/5.Posting.rst: clarify use of Reported-by: tag docs, kprobes: Fix the wrong location of Kprobes docs: add a man-pages link to the front page docs: put atomic*.txt and memory-barriers.txt into the core-api book docs: move asm-annotations.rst into core-api docs: remove some index.rst cruft docs: reconfigure the HTML left column docs: Rewrite the front page docs: promote the title of process/index.rst Documentation: devres: add missing SPI helper Documentation: devres: add missing PINCTRL helpers docs: hugetlbpage.rst: fix a typo of hugepage size docs/zh_CN: Add new translation of admin-guide/bootconfig.rst ...
2022-09-27Documentation/ABI: correct possessive "its" typosRandy Dunlap
Correct all uses of "it's" that are meant to be possessive "its". Signed-off-by: Randy Dunlap <rdunlap@infradead.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Link: https://lore.kernel.org/r/20220801025207.29971-1-rdunlap@infradead.org Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2022-08-25Documentation/ABI: Mention retbleed vulnerability info file for sysfsSalvatore Bonaccorso
While reporting for the AMD retbleed vulnerability was added in 6b80b59b3555 ("x86/bugs: Report AMD retbleed vulnerability") the new sysfs file was not mentioned so far in the ABI documentation for sysfs-devices-system-cpu. Fix that. Fixes: 6b80b59b3555 ("x86/bugs: Report AMD retbleed vulnerability") Signed-off-by: Salvatore Bonaccorso <carnil@debian.org> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lore.kernel.org/r/20220801091529.325327-1-carnil@debian.org
2022-08-04Merge tag 'driver-core-6.0-rc1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core Pull driver core / kernfs updates from Greg KH: "Here is the set of driver core and kernfs changes for 6.0-rc1. The "biggest" thing in here is some scalability improvements for kernfs for large systems. Other than that, included in here are: - arch topology and cache info changes that have been reviewed and discussed a lot. - potential error path cleanup fixes - deferred driver probe cleanups - firmware loader cleanups and tweaks - documentation updates - other small things All of these have been in the linux-next tree for a while with no reported problems" * tag 'driver-core-6.0-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (63 commits) docs: embargoed-hardware-issues: fix invalid AMD contact email firmware_loader: Replace kmap() with kmap_local_page() sysfs docs: ABI: Fix typo in comment kobject: fix Kconfig.debug "its" grammar kernfs: Fix typo 'the the' in comment docs: driver-api: firmware: add driver firmware guidelines. (v3) arch_topology: Fix cache attributes detection in the CPU hotplug path ACPI: PPTT: Leave the table mapped for the runtime usage cacheinfo: Use atomic allocation for percpu cache attributes drivers/base: fix userspace break from using bin_attributes for cpumap and cpulist MAINTAINERS: Change mentions of mpm to olivia docs: ABI: sysfs-devices-soc: Update Lee Jones' email address docs: ABI: sysfs-class-pwm: Update Lee Jones' email address Documentation/process: Add embargoed HW contact for LLVM Revert "kernfs: Change kernfs_notify_list to llist." ACPI: Remove the unused find_acpi_cpu_cache_topology() arch_topology: Warn that topology for nested clusters is not supported arch_topology: Add support for parsing sockets in /cpu-map arch_topology: Set cluster identifier in each core/thread from /cpu-map arch_topology: Limit span of cpu_clustergroup_mask() ...
2022-06-27ABI: testing/sysfs-devices-system-cpu: remove duplicated core_idMauro Carvalho Chehab
This was already defined at stable/sysfs-devices-system-cpu with the same description, as pointed by get_abi.pl: Warning: /sys/devices/system/cpu/cpuX/topology/core_id is defined 2 times: Documentation/ABI/stable/sysfs-devices-system-cpu:38 Documentation/ABI/testing/sysfs-devices-system-cpu:69 Remove the duplicated one. Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org> Link: https://lore.kernel.org/r/1e92337c1ef74f5eb9e1c1871e20b858b490d269.1656235926.git.mchehab@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-06-23arm64/sme: Expose SMIDR through sysfsMark Brown
We currently expose MIDR and REVID to userspace through sysfs to enable it to make decisions based on the specific implementation. Since SME supports implementations where streaming mode is provided by a separate hardware unit called a SMCU it provides a similar ID register SMIDR. Expose it to userspace via sysfs when the system supports SME along with the other ID registers. Since we disable the SME priority mapping feature if it is supported by hardware we currently mask out the SMPS bit which reports that it is supported. Signed-off-by: Mark Brown <broonie@kernel.org> Link: https://lore.kernel.org/r/20220607132857.1358361-1-broonie@kernel.org Signed-off-by: Will Deacon <will@kernel.org>
2022-05-21x86/speculation/mmio: Add sysfs reporting for Processor MMIO Stale DataPawan Gupta
Add the sysfs reporting file for Processor MMIO Stale Data vulnerability. It exposes the vulnerability and mitigation state similar to the existing files for the other hardware vulnerabilities. Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com> Signed-off-by: Borislav Petkov <bp@suse.de>
2022-03-21Merge tag 'x86_cpu_for_v5.18_rc1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 cpu feature updates from Borislav Petkov: - Merge the AMD and Intel PPIN code into a shared one by both vendors. Add the PPIN number to sysfs so that sockets can be identified when replacement is needed - Minor fixes and cleanups * tag 'x86_cpu_for_v5.18_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/cpu: Clear SME feature flag when not in use x86/cpufeatures: Put the AMX macros in the word 18 block topology/sysfs: Add PPIN in sysfs under cpu topology topology/sysfs: Add format parameter to macro defining "show" functions for proc x86/cpu: Read/save PPIN MSR during initialization x86/cpu: X86_FEATURE_INTEL_PPIN finally has a CPUID bit x86/cpu: Merge Intel and AMD ppin_init() functions x86/CPU/AMD: Use default_groups in kobj_type
2022-03-10docs: sysfs-devices-system-cpu: document "asymm" value for mte_tcf_preferredEvgenii Stepanov
It was added in commit 766121ba5de3 ("arm64/mte: Add userspace interface for enabling asymmetric mode"). Signed-off-by: Evgenii Stepanov <eugenis@google.com> Reviewed-by: Mark Brown <broonie@kernel.org> Link: https://lore.kernel.org/r/20220309215943.87831-1-eugenis@google.com Signed-off-by: Will Deacon <will@kernel.org>
2022-02-01topology/sysfs: Add PPIN in sysfs under cpu topologyTony Luck
PPIN is the Protected Processor Identification Number. This is used to identify the socket as a Field Replaceable Unit (FRU). Existing code only displays this when reporting errors. But this makes it inconvenient for large clusters to use it for its intended purpose of inventory control. Add ppin to /sys/devices/system/cpu/cpu*/topology to make what is already available using RDMSR more easily accessible. Make the file read only for root in case there are still people concerned about making a unique system "serial number" available. Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Borislav Petkov <bp@suse.de> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Link: https://lore.kernel.org/r/20220131230111.2004669-6-tony.luck@intel.com
2021-12-03docs: document the sysfs ABI for "isolated"Kohei Tarumizu
Add missing documentation of sysfs ABI for "isolated". It was added by commit 59f30abe94bf("show isolated cpus in sysfs"). However, there is no documentation for these interface. Signed-off-by: Kohei Tarumizu <tarumizu.kohei@fujitsu.com> Link: https://lore.kernel.org/r/20211201115957.254224-3-tarumizu.kohei@fujitsu.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-12-03docs: document the sysfs ABI for "nohz_full"Kohei Tarumizu
Add missing documentation of sysfs ABI for "nohz_full". It was added by commit 6570a9a1ce3a("show nohz_full cpus in sysfs"). However, there is no documentation for these interface. Signed-off-by: Kohei Tarumizu <tarumizu.kohei@fujitsu.com> Link: https://lore.kernel.org/r/20211201115957.254224-2-tarumizu.kohei@fujitsu.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-10-05ABI: sysfs-devices-system-cpu: use cpuX instead of cpu#Mauro Carvalho Chehab
Some What entries here use cpu# as a wildcard, while others use, instead, cpuX. As scripts/get_abi.pl doesn't consider "#" as a wildcard, replace: cpu# -> cpuX inside the file. Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org> Link: https://lore.kernel.org/r/60b1a79189d1a9d9f1c9c9c299770e69b18972fd.1632994837.git.mchehab+huawei@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-09-21ABI: sysfs-devices-system-cpu: use wildcards on What definitionsMauro Carvalho Chehab
An "N" upper letter is not a wildcard, nor can easily be identified by script, specially since the USB sysfs define things like. bNumInterfaces. Use, instead, <N>, in order to let script/get_abi.pl to convert it into a Regex. Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org> Link: https://lore.kernel.org/r/d18385a391b6797373a5d1382ea024857fb29987.1631782432.git.mchehab+huawei@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-08-31Merge remote-tracking branch 'tip/sched/arm64' into for-next/coreCatalin Marinas
* tip/sched/arm64: (785 commits) Documentation: arm64: describe asymmetric 32-bit support arm64: Remove logic to kill 32-bit tasks on 64-bit-only cores arm64: Hook up cmdline parameter to allow mismatched 32-bit EL0 arm64: Advertise CPUs capable of running 32-bit applications in sysfs arm64: Prevent offlining first CPU with 32-bit EL0 on mismatched system arm64: exec: Adjust affinity for compat tasks with mismatched 32-bit EL0 arm64: Implement task_cpu_possible_mask() sched: Introduce dl_task_check_affinity() to check proposed affinity sched: Allow task CPU affinity to be restricted on asymmetric systems sched: Split the guts of sched_setaffinity() into a helper function sched: Introduce task_struct::user_cpus_ptr to track requested affinity sched: Reject CPU affinity changes based on task_cpu_possible_mask() cpuset: Cleanup cpuset_cpus_allowed_fallback() use in select_fallback_rq() cpuset: Honour task_cpu_possible_mask() in guarantee_online_cpus() cpuset: Don't use the cpu_possible_mask as a last resort for cgroup v1 sched: Introduce task_cpu_possible_mask() to limit fallback rq selection sched: Cgroup SCHED_IDLE support sched/topology: Skip updating masks for non-online nodes Linux 5.14-rc6 lib: use PFN_PHYS() in devmem_is_allowed() ...
2021-08-20arm64: Advertise CPUs capable of running 32-bit applications in sysfsWill Deacon
Since 32-bit applications will be killed if they are caught trying to execute on a 64-bit-only CPU in a mismatched system, advertise the set of 32-bit capable CPUs to userspace in sysfs. Signed-off-by: Will Deacon <will@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Link: https://lore.kernel.org/r/20210730112443.23245-14-will@kernel.org
2021-07-28Documentation: document the preferred tag checking mode featurePeter Collingbourne
Document the functionality added in the previous patches. Link: https://linux-review.googlesource.com/id/I48217cc3e8b8da33abc08cbaddc11cf4360a1b86 Signed-off-by: Peter Collingbourne <pcc@google.com> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Acked-by: Will Deacon <will@kernel.org> Link: https://lore.kernel.org/r/20210727205300.2554659-6-pcc@google.com Acked-by: Will Deacon <will@kernel.org> [catalin.marinas@arm.com: clarify that the change happens on task scheduling] Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2021-05-13docs: typo fixes in Documentation/ABI/Carlos Bilbao
Fix the following typos in the Documentation/ABI/ directory: - In file obsolete/sysfs-cpuidle, change "obselete" for "obsolete". - In file removed/sysfs-kernel-uids, change "propotional" for "proportional". - In directory stable/, fix the following words: "associtated" for "associated", "hexidecimal" for "hexadecimal", "vlue" for "value", "csed" for "caused" and "wrtie" for "write". This updates a total of five files. - In directory testing/, fix the following words: "subystem" for "subsystem", "isochrnous" for "isochronous", "Desctiptors" for "Descriptors", "picutre" for "picture", "capture" for "capture", "occured" for "ocurred", "connnected" for "connected","agressively" for "aggressively","manufacturee" for "manufacturer" and "transaction" for "transaction", "malformatted" for "incorrectly formated" ,"internel" for "internal", "writtento" for "written to", "specificed" for "specified", "beyound" for "beyond", "Symetric" for "Symmetric". This updates a total of eleven files. Signed-off-by: Carlos Bilbao <bilbao@vt.edu> Reviewed-by: Randy Dunlap <rdunlap@infradead.org> Reviewed-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org> Link: https://lore.kernel.org/r/5710038.lOV4Wx5bFT@iron-maiden Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2021-05-03docs: correct URL to bios and kernel developer's guideAnatoly Pugachev
correct URL to bios and kernel developer's guide on amd.com site Signed-off-by: Anatoly Pugachev <matorola@gmail.com> Link: https://lore.kernel.org/r/20210428104851.GA10572@u164.east.ru [jc: fixed resulting sphinx warning] Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2020-12-15cppc_cpufreq: expose information on frequency domainsIonela Voinescu
Use the existing sysfs attribute "freqdomain_cpus" to expose information to userspace about CPUs in the same frequency domain. Signed-off-by: Ionela Voinescu <ionela.voinescu@arm.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Tested-by: Mian Yousaf Kaukab <ykaukab@suse.de> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2020-10-30docs: ABI: cleanup several ABI documentsMauro Carvalho Chehab
There are some ABI documents that, while they don't generate any warnings, they have issues when parsed by get_abi.pl script on its output result. Address them, in order to provide a clean output. Reviewed-by: Tom Rix <trix@redhat.com> # for fpga-manager Reviewed-By: Kajol Jain<kjain@linux.ibm.com> # for sysfs-bus-event_source-devices-hv_gpci and sysfs-bus-event_source-devices-hv_24x7 Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> #for IIO Acked-by: Oded Gabbay <oded.gabbay@gmail.com> # for Habanalabs Acked-by: Vaibhav Jain <vaibhav@linux.ibm.com> # for sysfs-bus-papr-pmem Acked-by: Cezary Rojewski <cezary.rojewski@intel.com> # for catpt Acked-by: Suzuki K Poulose <suzuki.poulose@arm.com> Acked-by: Ilya Dryomov <idryomov@gmail.com> # for rbd Acked-by: Jonathan Corbet <corbet@lwn.net> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org> Link: https://lore.kernel.org/r/5bc78e5b68ed1e9e39135173857cb2e753be868f.1604042072.git.mchehab+huawei@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-10-30docs: ABI: testing: make the files compatible with ReST outputMauro Carvalho Chehab
Some files over there won't parse well by Sphinx. Fix them. Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> # for IIO Acked-by: Fabrice Gasnier <fabrice.gasnier@st.com> Acked-by: Jonathan Corbet <corbet@lwn.net> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org> Link: https://lore.kernel.org/r/58cf3c2d611e0197fb215652719ebd82ca2658db.1604042072.git.mchehab+huawei@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-06-09Merge branch 'x86/srbds' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 srbds fixes from Thomas Gleixner: "The 9th episode of the dime novel "The performance killer" with the subtitle "Slow Randomizing Boosts Denial of Service". SRBDS is an MDS-like speculative side channel that can leak bits from the random number generator (RNG) across cores and threads. New microcode serializes the processor access during the execution of RDRAND and RDSEED. This ensures that the shared buffer is overwritten before it is released for reuse. This is equivalent to a full bus lock, which means that many threads running the RNG instructions in parallel have the same effect as the same amount of threads issuing a locked instruction targeting an address which requires locking of two cachelines at once. The mitigation support comes with the usual pile of unpleasant ingredients: - command line options - sysfs file - microcode checks - a list of vulnerable CPUs identified by model and stepping this time which requires stepping match support for the cpu match logic. - the inevitable slowdown of affected CPUs" * branch 'x86/srbds' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/speculation: Add Ivy Bridge to affected list x86/speculation: Add SRBDS vulnerability and mitigation documentation x86/speculation: Add Special Register Buffer Data Sampling (SRBDS) mitigation x86/cpu: Add 'table' argument to cpu_matches()
2020-06-05Merge tag 'powerpc-5.8-1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux Pull powerpc updates from Michael Ellerman: - Support for userspace to send requests directly to the on-chip GZIP accelerator on Power9. - Rework of our lockless page table walking (__find_linux_pte()) to make it safe against parallel page table manipulations without relying on an IPI for serialisation. - A series of fixes & enhancements to make our machine check handling more robust. - Lots of plumbing to add support for "prefixed" (64-bit) instructions on Power10. - Support for using huge pages for the linear mapping on 8xx (32-bit). - Remove obsolete Xilinx PPC405/PPC440 support, and an associated sound driver. - Removal of some obsolete 40x platforms and associated cruft. - Initial support for booting on Power10. - Lots of other small features, cleanups & fixes. Thanks to: Alexey Kardashevskiy, Alistair Popple, Andrew Donnellan, Andrey Abramov, Aneesh Kumar K.V, Balamuruhan S, Bharata B Rao, Bulent Abali, Cédric Le Goater, Chen Zhou, Christian Zigotzky, Christophe JAILLET, Christophe Leroy, Dmitry Torokhov, Emmanuel Nicolet, Erhard F., Gautham R. Shenoy, Geoff Levand, George Spelvin, Greg Kurz, Gustavo A. R. Silva, Gustavo Walbon, Haren Myneni, Hari Bathini, Joel Stanley, Jordan Niethe, Kajol Jain, Kees Cook, Leonardo Bras, Madhavan Srinivasan., Mahesh Salgaonkar, Markus Elfring, Michael Neuling, Michal Simek, Nathan Chancellor, Nathan Lynch, Naveen N. Rao, Nicholas Piggin, Oliver O'Halloran, Paul Mackerras, Pingfan Liu, Qian Cai, Ram Pai, Raphael Moreira Zinsly, Ravi Bangoria, Sam Bobroff, Sandipan Das, Segher Boessenkool, Stephen Rothwell, Sukadev Bhattiprolu, Tyrel Datwyler, Wolfram Sang, Xiongfeng Wang. * tag 'powerpc-5.8-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (299 commits) powerpc/pseries: Make vio and ibmebus initcalls pseries specific cxl: Remove dead Kconfig options powerpc: Add POWER10 architected mode powerpc/dt_cpu_ftrs: Add MMA feature powerpc/dt_cpu_ftrs: Enable Prefixed Instructions powerpc/dt_cpu_ftrs: Advertise support for ISA v3.1 if selected powerpc: Add support for ISA v3.1 powerpc: Add new HWCAP bits powerpc/64s: Don't set FSCR bits in INIT_THREAD powerpc/64s: Save FSCR to init_task.thread.fscr after feature init powerpc/64s: Don't let DT CPU features set FSCR_DSCR powerpc/64s: Don't init FSCR_DSCR in __init_FSCR() powerpc/32s: Fix another build failure with CONFIG_PPC_KUAP_DEBUG powerpc/module_64: Use special stub for _mcount() with -mprofile-kernel powerpc/module_64: Simplify check for -mprofile-kernel ftrace relocations powerpc/module_64: Consolidate ftrace code powerpc/32: Disable KASAN with pages bigger than 16k powerpc/uaccess: Don't set KUEP by default on book3s/32 powerpc/uaccess: Don't set KUAP by default on book3s/32 powerpc/8xx: Reduce time spent in allow_user_access() and friends ...
2020-05-19Documentation: cpuidle: update the documentHanjun Guo
Update the document after the remove of cpuidle_sysfs_switch. Signed-off-by: Hanjun Guo <guohanjun@huawei.com> Reviewed-by: Doug Smythies <dsmythies@telus.net> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>