linux/drivers/base/cpu.c, branch v5.7

Merge tag 'smp-core-2020-03-30' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2020-03-31T01:06:39Z

Pull core SMP updates from Thomas Gleixner: "CPU (hotplug) updates: - Support for locked CSD objects in smp_call_function_single_async() which allows to simplify callsites in the scheduler core and MIPS - Treewide consolidation of CPU hotplug functions which ensures the consistency between the sysfs interface and kernel state. The low level functions cpu_up/down() are now confined to the core code and not longer accessible from random code" * tag 'smp-core-2020-03-30' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (22 commits) cpu/hotplug: Ignore pm_wakeup_pending() for disable_nonboot_cpus() cpu/hotplug: Hide cpu_up/down() cpu/hotplug: Move bringup of secondary CPUs out of smp_init() torture: Replace cpu_up/down() with add/remove_cpu() firmware: psci: Replace cpu_up/down() with add/remove_cpu() xen/cpuhotplug: Replace cpu_up/down() with device_online/offline() parisc: Replace cpu_up/down() with add/remove_cpu() sparc: Replace cpu_up/down() with add/remove_cpu() powerpc: Replace cpu_up/down() with add/remove_cpu() x86/smp: Replace cpu_up/down() with add/remove_cpu() arm64: hibernate: Use bringup_hibernate_cpu() cpu/hotplug: Provide bringup_hibernate_cpu() arm64: Use reboot_cpu instead of hardconding it to 0 arm64: Don't use disable_nonboot_cpus() ARM: Use reboot_cpu instead of hardcoding it to 0 ARM: Don't use disable_nonboot_cpus() ia64: Replace cpu_down() with smp_shutdown_nonboot_cpus() cpu/hotplug: Create a new function to shutdown nonboot cpus cpu/hotplug: Add new {add,remove}_cpu() functions sched/core: Remove rq.hrtick_csd_pending ...

cpu/hotplug: Hide cpu_up/down()

2020-03-25T11:59:38Z

Use separate functions for the device core to bring a CPU up and down. Users outside the device core must use add/remove_cpu() which will take care of extra housekeeping work like keeping sysfs in sync. Make cpu_up/down() static and replace the extra layer of indirection. [ tglx: Removed the extra wrapper functions and adjusted function names ] Signed-off-by: Qais Yousef Signed-off-by: Thomas Gleixner Link: https://lkml.kernel.org/r/20200323135110.30522-18-qais.yousef@arm.com

drivers/base/cpu: Simplify s*nprintf() usages

2020-03-11T08:08:44Z

Use the simpler sprintf() instead of snprintf() or scnprintf() in a single-shot sysfs output callbacks where you are very sure that it won't go over PAGE_SIZE buffer limit. Signed-off-by: Takashi Iwai Link: https://lore.kernel.org/r/20200311080207.12046-3-tiwai@suse.de Signed-off-by: Greg Kroah-Hartman

drivers/base/cpu: Use scnprintf() for avoiding potential buffer overflow

2020-03-11T08:08:44Z

Since snprintf() returns the would-be-output size instead of the actual output size, the succeeding calls may go beyond the given buffer limit. Fix it by replacing with scnprintf(). Signed-off-by: Takashi Iwai Link: https://lore.kernel.org/r/20200311080207.12046-2-tiwai@suse.de Signed-off-by: Greg Kroah-Hartman

x86/bugs: Add ITLB_MULTIHIT bug infrastructure

2019-11-04T11:22:01Z

Some processors may incur a machine check error possibly resulting in an unrecoverable CPU lockup when an instruction fetch encounters a TLB multi-hit in the instruction TLB. This can occur when the page size is changed along with either the physical address or cache type. The relevant erratum can be found here: https://bugzilla.kernel.org/show_bug.cgi?id=205195 There are other processors affected for which the erratum does not fully disclose the impact. This issue affects both bare-metal x86 page tables and EPT. It can be mitigated by either eliminating the use of large pages or by using careful TLB invalidations when changing the page size in the page tables. Just like Spectre, Meltdown, L1TF and MDS, a new bit has been allocated in MSR_IA32_ARCH_CAPABILITIES (PSCHANGE_MC_NO) and will be set on CPUs which are mitigated against this issue. Signed-off-by: Vineela Tummalapalli Co-developed-by: Pawan Gupta Signed-off-by: Pawan Gupta Signed-off-by: Paolo Bonzini Signed-off-by: Thomas Gleixner

x86/speculation/taa: Add sysfs reporting for TSX Async Abort

2019-10-28T07:36:59Z

Add the sysfs reporting file for TSX Async Abort. It exposes the vulnerability and the mitigation state similar to the existing files for the other hardware vulnerabilities. Sysfs file path is: /sys/devices/system/cpu/vulnerabilities/tsx_async_abort Signed-off-by: Pawan Gupta Signed-off-by: Borislav Petkov Signed-off-by: Thomas Gleixner Tested-by: Neelima Krishnan Reviewed-by: Mark Gross Reviewed-by: Tony Luck Reviewed-by: Greg Kroah-Hartman Reviewed-by: Josh Poimboeuf

Merge branch 'x86-mds-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2019-05-14T14:57:29Z

Pull x86 MDS mitigations from Thomas Gleixner: "Microarchitectural Data Sampling (MDS) is a hardware vulnerability which allows unprivileged speculative access to data which is available in various CPU internal buffers. This new set of misfeatures has the following CVEs assigned: CVE-2018-12126 MSBDS Microarchitectural Store Buffer Data Sampling CVE-2018-12130 MFBDS Microarchitectural Fill Buffer Data Sampling CVE-2018-12127 MLPDS Microarchitectural Load Port Data Sampling CVE-2019-11091 MDSUM Microarchitectural Data Sampling Uncacheable Memory MDS attacks target microarchitectural buffers which speculatively forward data under certain conditions. Disclosure gadgets can expose this data via cache side channels. Contrary to other speculation based vulnerabilities the MDS vulnerability does not allow the attacker to control the memory target address. As a consequence the attacks are purely sampling based, but as demonstrated with the TLBleed attack samples can be postprocessed successfully. The mitigation is to flush the microarchitectural buffers on return to user space and before entering a VM. It's bolted on the VERW instruction and requires a microcode update. As some of the attacks exploit data structures shared between hyperthreads, full protection requires to disable hyperthreading. The kernel does not do that by default to avoid breaking unattended updates. The mitigation set comes with documentation for administrators and a deeper technical view" * 'x86-mds-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (23 commits) x86/speculation/mds: Fix documentation typo Documentation: Correct the possible MDS sysfs values x86/mds: Add MDSUM variant to the MDS documentation x86/speculation/mds: Add 'mitigations=' support for MDS x86/speculation/mds: Print SMT vulnerable on MSBDS with mitigations off x86/speculation/mds: Fix comment x86/speculation/mds: Add SMT warning message x86/speculation: Move arch_smt_update() call to after mitigation decisions x86/speculation/mds: Add mds=full,nosmt cmdline option Documentation: Add MDS vulnerability documentation Documentation: Move L1TF to separate directory x86/speculation/mds: Add mitigation mode VMWERV x86/speculation/mds: Add sysfs reporting for MDS x86/speculation/mds: Add mitigation control for MDS x86/speculation/mds: Conditionally clear CPU buffers on idle entry x86/kvm/vmx: Add MDS protection when L1D Flush is not active x86/speculation/mds: Clear CPU buffers on exit to user x86/speculation/mds: Add mds_clear_cpu_buffers() x86/kvm: Expose X86_FEATURE_MD_CLEAR to guests x86/speculation/mds: Add BUG_MSBDS_ONLY ...

Merge tag 'driver-core-5.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core

2019-03-06T22:52:48Z

Pull driver core updates from Greg KH: "Here is the big driver core patchset for 5.1-rc1 More patches than "normal" here this merge window, due to some work in the driver core by Alexander Duyck to rework the async probe functionality to work better for a number of devices, and independant work from Rafael for the device link functionality to make it work "correctly". Also in here is: - lots of BUS_ATTR() removals, the macro is about to go away - firmware test fixups - ihex fixups and simplification - component additions (also includes i915 patches) - lots of minor coding style fixups and cleanups. All of these have been in linux-next for a while with no reported issues" * tag 'driver-core-5.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (65 commits) driver core: platform: remove misleading err_alloc label platform: set of_node in platform_device_register_full() firmware: hardcode the debug message for -ENOENT driver core: Add missing description of new struct device_link field driver core: Fix PM-runtime for links added during consumer probe drivers/component: kerneldoc polish async: Add cmdline option to specify drivers to be async probed driver core: Fix possible supplier PM-usage counter imbalance PM-runtime: Fix __pm_runtime_set_status() race with runtime resume driver: platform: Support parsing GpioInt 0 in platform_get_irq() selftests: firmware: fix verify_reqs() return value Revert "selftests: firmware: remove use of non-standard diff -Z option" Revert "selftests: firmware: add CONFIG_FW_LOADER_USER_HELPER_FALLBACK to config" device: Fix comment for driver_data in struct device kernfs: Allocating memory for kernfs_iattrs with kmem_cache. sysfs: remove unused include of kernfs-internal.h driver core: Postpone DMA tear-down until after devres release driver core: Document limitation related to DL_FLAG_RPM_ACTIVE PM-runtime: Take suppliers into account in __pm_runtime_set_status() device.h: Add __cold to dev_ logging functions ...

x86/speculation/mds: Add sysfs reporting for MDS

2019-03-06T20:52:14Z

Add the sysfs reporting file for MDS. It exposes the vulnerability and mitigation state similar to the existing files for the other speculative hardware vulnerabilities. Signed-off-by: Thomas Gleixner Reviewed-by: Greg Kroah-Hartman Reviewed-by: Borislav Petkov Reviewed-by: Jon Masters Tested-by: Jon Masters

PM / core: Add support to skip power management in device/driver model

2019-02-19T09:42:43Z

All device objects in the driver model contain fields that control the handling of various power management activities. However, it's not always useful. There are few instances where pseudo devices are added to the model just to take advantage of many other features like kobjects, udev events, and so on. One such example is cpu devices and their caches. The sysfs for the cpu caches are managed by adding devices with cpu as the parent in cpu_device_create() when secondary cpu is brought online. Generally when the secondary CPUs are hotplugged back in as part of resume from suspend-to-ram, we call cpu_device_create() from the cpu hotplug state machine while the cpu device associated with that CPU is not yet ready to be resumed as the device_resume() call happens bit later. It's not really needed to set the flag is_prepared for cpu devices as they are mostly pseudo device and hotplug framework deals with state machine and not managed through the cpu device. This often results in annoying warning when resuming: Enabling non-boot CPUs ... CPU1: Booted secondary processor cache: parent cpu1 should not be sleeping CPU1 is up CPU2: Booted secondary processor cache: parent cpu2 should not be sleeping CPU2 is up .... and so on. So in order to fix these kind of errors, we could just completely avoid doing any power management related initialisations and operations if they are not used by these devices. Add no_pm flags to indicate that the device doesn't require any sort of PM activities and all of them can be completely skipped. We can use the same flag to also avoid adding not used *power* sysfs entries for these devices. For now, lets use this for cpu cache devices. Reviewed-by: Ulf Hansson Signed-off-by: Sudeep Holla Tested-by: Eugeniu Rosca Signed-off-by: Rafael J. Wysocki