linux/drivers/base/cpu.c, branch v6.8

Merge tag 'driver-core-6.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core

2024-01-18T17:48:40Z

Pull driver core updates from Greg KH: "Here are the set of driver core and kernfs changes for 6.8-rc1. Nothing major in here this release cycle, just lots of small cleanups and some tweaks on kernfs that in the very end, got reverted and will come back in a safer way next release cycle. Included in here are: - more driver core 'const' cleanups and fixes - fw_devlink=rpm is now the default behavior - kernfs tiny changes to remove some string functions - cpu handling in the driver core is updated to work better on many systems that add topologies and cpus after booting - other minor changes and cleanups All of the cpu handling patches have been acked by the respective maintainers and are coming in here in one series. Everything has been in linux-next for a while with no reported issues" * tag 'driver-core-6.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (51 commits) Revert "kernfs: convert kernfs_idr_lock to an irq safe raw spinlock" kernfs: convert kernfs_idr_lock to an irq safe raw spinlock class: fix use-after-free in class_register() PM: clk: make pm_clk_add_notifier() take a const pointer EDAC: constantify the struct bus_type usage kernfs: fix reference to renamed function driver core: device.h: fix Excess kernel-doc description warning driver core: class: fix Excess kernel-doc description warning driver core: mark remaining local bus_type variables as const driver core: container: make container_subsys const driver core: bus: constantify subsys_register() calls driver core: bus: make bus_sort_breadthfirst() take a const pointer kernfs: d_obtain_alias(NULL) will do the right thing... driver core: Better advertise dev_err_probe() kernfs: Convert kernfs_path_from_node_locked() from strlcpy() to strscpy() kernfs: Convert kernfs_name_locked() from strlcpy() to strscpy() kernfs: Convert kernfs_walk_ns() from strlcpy() to strscpy() initramfs: Expose retained initrd as sysfs file fs/kernfs/dir: obey S_ISGID kernel/cgroup: use kernfs_create_dir_ns() ...

drivers/base/cpu: crash data showing should depends on KEXEC_CORE

2023-12-07T00:12:48Z

After commit 88a6f8994421 ("crash: memory and CPU hotplug sysfs attributes"), on x86_64, if only below kernel configs related to kdump are set, compiling error are triggered. ---- CONFIG_CRASH_CORE=y CONFIG_KEXEC_CORE=y CONFIG_CRASH_DUMP=y CONFIG_CRASH_HOTPLUG=y ------ ------------------------------------------------------ drivers/base/cpu.c: In function `crash_hotplug_show': drivers/base/cpu.c:309:40: error: implicit declaration of function `crash_hotplug_cpu_support'; did you mean `crash_hotplug_show'? [-Werror=implicit-function-declaration] 309 | return sysfs_emit(buf, "%d\n", crash_hotplug_cpu_support()); | ^~~~~~~~~~~~~~~~~~~~~~~~~ | crash_hotplug_show cc1: some warnings being treated as errors ------------------------------------------------------ CONFIG_KEXEC is used to enable kexec_load interface, the crash_notes/crash_notes_size/crash_hotplug showing depends on CONFIG_KEXEC is incorrect. It should depend on KEXEC_CORE instead. Fix it now. Link: https://lkml.kernel.org/r/20231128055248.659808-1-bhe@redhat.com Fixes: 88a6f8994421 ("crash: memory and CPU hotplug sysfs attributes") Signed-off-by: Baoquan He Tested-by: Ignat Korchagin [compile-time only] Tested-by: Alexander Gordeev Reviewed-by: Eric DeVolder Cc: Signed-off-by: Andrew Morton

drivers: base: Print a warning instead of panic() when register_cpu() fails

2023-12-06T03:41:49Z

loongarch, mips, parisc, riscv and sh all print a warning if register_cpu() returns an error. Architectures that use GENERIC_CPU_DEVICES call panic() instead. Errors in this path indicate something is wrong with the firmware description of the platform, but the kernel is able to keep running. Downgrade this to a warning to make it easier to debug this issue. This will allow architectures that switching over to GENERIC_CPU_DEVICES to drop their warning, but keep the existing behaviour. Signed-off-by: James Morse Reviewed-by: "Russell King (Oracle)" Reviewed-by: Shaoqin Huang Signed-off-by: "Russell King (Oracle)" Reviewed-by: Gavin Shan Reviewed-by: Jonathan Cameron Reviewed-by: Thomas Gleixner Link: https://lore.kernel.org/r/E1r5R3W-00CszU-GM@rmk-PC.armlinux.org.uk Signed-off-by: Greg Kroah-Hartman

drivers: base: add arch_cpu_is_hotpluggable()

2023-12-06T03:41:48Z

The differences between architecture specific implementations of arch_register_cpu() are down to whether the CPU is hotpluggable or not. Rather than overriding the weak version of arch_register_cpu(), provide a function that can be used to provide this detail instead. Reviewed-by: Shaoqin Huang Signed-off-by: "Russell King (Oracle)" Reviewed-by: Jonathan Cameron Reviewed-by: Gavin Shan Reviewed-by: Thomas Gleixner Link: https://lore.kernel.org/r/E1r5R3M-00CszH-6r@rmk-PC.armlinux.org.uk Signed-off-by: Greg Kroah-Hartman

drivers: base: Implement weak arch_unregister_cpu()

2023-12-06T03:41:48Z

Add arch_unregister_cpu() to allow the ACPI machinery to call unregister_cpu(). This is enough for arm64, riscv and loongarch, but needs to be overridden by x86 and ia64 who need to do more work. CC: Jean-Philippe Brucker Signed-off-by: James Morse Reviewed-by: Shaoqin Huang Signed-off-by: "Russell King (Oracle)" Reviewed-by: Gavin Shan Reviewed-by: Jonathan Cameron Reviewed-by: Thomas Gleixner Link: https://lore.kernel.org/r/E1r5R3H-00CszC-2n@rmk-PC.armlinux.org.uk Signed-off-by: Greg Kroah-Hartman

drivers: base: Allow parts of GENERIC_CPU_DEVICES to be overridden

2023-12-06T03:41:48Z

Architectures often have extra per-cpu work that needs doing before a CPU is registered, often to determine if a CPU is hotpluggable. To allow the ACPI architectures to use GENERIC_CPU_DEVICES, move the cpu_register() call into arch_register_cpu(), which is made __weak so architectures with extra work can override it. This aligns with the way x86, ia64 and loongarch register hotplug CPUs when they become present. Signed-off-by: James Morse Reviewed-by: Shaoqin Huang Reviewed-by: Gavin Shan Signed-off-by: "Russell King (Oracle)" Reviewed-by: Jonathan Cameron Reviewed-by: Thomas Gleixner Link: https://lore.kernel.org/r/E1r5R3B-00Csz6-Uh@rmk-PC.armlinux.org.uk Signed-off-by: Greg Kroah-Hartman

drivers: base: Use present CPUs in GENERIC_CPU_DEVICES

2023-12-06T03:41:48Z

Three of the five ACPI architectures create sysfs entries using register_cpu() for present CPUs, whereas arm64, riscv and all GENERIC_CPU_DEVICES do this for possible CPUs. Registering a CPU is what causes them to show up in sysfs. It makes very little sense to register all possible CPUs. Registering a CPU is what triggers the udev notifications allowing user-space to react to newly added CPUs. To allow all five ACPI architectures to use GENERIC_CPU_DEVICES, change it to use for_each_present_cpu(). Making the ACPI architectures use GENERIC_CPU_DEVICES is a pre-requisite step to centralise their register_cpu() logic, before moving it into the ACPI processor driver. When we add support for register CPUs from ACPI in a later patch, we will avoid registering CPUs in this path. Of the ACPI architectures that register possible CPUs, arm64 and riscv do not support making possible CPUs present as they use the weak 'always fails' version of arch_register_cpu(). Only two of the eight architectures that use GENERIC_CPU_DEVICES have a distinction between present and possible CPUs. The following architectures use GENERIC_CPU_DEVICES but are not SMP, so possible == present: * m68k * microblaze * nios2 The following architectures use GENERIC_CPU_DEVICES and consider possible == present: * csky: setup_smp() * processor_probe() sets possible for all CPUs and present for all CPUs except the boot cpu, which will have been done by init/main.c::start_kernel(). um appears to be a subarchitecture of x86. The remaining architecture using GENERIC_CPU_DEVICES are: * openrisc and hexagon: where smp_init_cpus() makes all CPUs < NR_CPUS possible, whereas smp_prepare_cpus() only makes CPUs < setup_max_cpus present. After this change, openrisc and hexagon systems that use the max_cpus command line argument would not see the other CPUs present in sysfs. This should not be a problem as these CPUs can't be brought online as _cpu_up() checks cpu_present(). After this change, only CPUs which are present appear in sysfs. Signed-off-by: James Morse Reviewed-by: Jonathan Cameron Reviewed-by: Gavin Shan Signed-off-by: "Russell King (Oracle)" Reviewed-by: Thomas Gleixner Link: https://lore.kernel.org/r/E1r5R36-00Csz0-Px@rmk-PC.armlinux.org.uk Signed-off-by: Greg Kroah-Hartman

Merge tag 'driver-core-6.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core

2023-09-01T16:43:18Z

Pull driver core updates from Greg KH: "Here is a small set of driver core updates and additions for 6.6-rc1. Included in here are: - stable kernel documentation updates - class structure const work from Ivan on various subsystems - kernfs tweaks - driver core tests! - kobject sanity cleanups - kobject structure reordering to save space - driver core error code handling fixups - other minor driver core cleanups All of these have been in linux-next for a while with no reported problems" * tag 'driver-core-6.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (32 commits) driver core: Call in reversed order in device_platform_notify_remove() driver core: Return proper error code when dev_set_name() fails kobject: Remove redundant checks for whether ktype is NULL kobject: Add sanity check for kset->kobj.ktype in kset_register() drivers: base: test: Add missing MODULE_* macros to root device tests drivers: base: test: Add missing MODULE_* macros for platform devices tests drivers: base: Free devm resources when unregistering a device drivers: base: Add basic devm tests for platform devices drivers: base: Add basic devm tests for root devices kernfs: fix missing kernfs_iattr_rwsem locking docs: stable-kernel-rules: mention that regressions must be prevented docs: stable-kernel-rules: fine-tune various details docs: stable-kernel-rules: make the examples for option 1 a proper list docs: stable-kernel-rules: move text around to improve flow docs: stable-kernel-rules: improve structure by changing headlines base/node: Remove duplicated include kernfs: attach uuid for every kernfs and report it in fsid kernfs: add stub helper for kernfs_generic_poll() x86/resctrl: make pseudo_lock_class a static const structure x86/MSR: make msr_class a static const structure ...

Merge tag 'mm-nonmm-stable-2023-08-28-22-48' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2023-08-29T21:53:51Z

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 ...

crash: memory and CPU hotplug sysfs attributes

2023-08-24T23:25:14Z

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 Reviewed-by: Sourabh Jain Acked-by: Hari Bathini Acked-by: Baoquan He Cc: Akhil Raj Cc: Bjorn Helgaas Cc: Borislav Petkov (AMD) Cc: Boris Ostrovsky Cc: Dave Hansen Cc: Dave Young Cc: David Hildenbrand Cc: Eric W. Biederman Cc: Greg Kroah-Hartman Cc: "H. Peter Anvin" Cc: Ingo Molnar Cc: Jonathan Corbet Cc: Konrad Rzeszutek Wilk Cc: Mimi Zohar Cc: Naveen N. Rao Cc: Oscar Salvador Cc: "Rafael J. Wysocki" Cc: Sean Christopherson Cc: Takashi Iwai Cc: Thomas Gleixner Cc: Thomas Weißschuh Cc: Valentin Schneider Cc: Vivek Goyal Cc: Vlastimil Babka Signed-off-by: Andrew Morton