Follow the patterns of the other architectures that use
GENERIC_CPU_VULNERABILITIES for riscv to introduce the ghostwrite
vulnerability and mitigation. The mitigation is to disable all vector
which is accomplished by clearing the bit from the cpufeature field.
Ghostwrite only affects thead c9xx CPUs that impelment xtheadvector, so
the vulerability will only be mitigated on these CPUs.
Signed-off-by: Charlie Jenkins <charlie@rivosinc.com>
Tested-by: Yangyu Chen <cyy@cyyself.name>
Link: https://lore.kernel.org/r/20241113-xtheadvector-v11-14-236c22791ef9@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Pull driver core updates from Greg KH:
"Here is the big set of driver core changes for 6.11-rc1.
Lots of stuff in here, with not a huge diffstat, but apis are evolving
which required lots of files to be touched. Highlights of the changes
in here are:
- platform remove callback api final fixups (Uwe took many releases
to get here, finally!)
- Rust bindings for basic firmware apis and initial driver-core
interactions.
It's not all that useful for a "write a whole driver in rust" type
of thing, but the firmware bindings do help out the phy rust
drivers, and the driver core bindings give a solid base on which
others can start their work.
There is still a long way to go here before we have a multitude of
rust drivers being added, but it's a great first step.
- driver core const api changes.
This reached across all bus types, and there are some fix-ups for
some not-common bus types that linux-next and 0-day testing shook
out.
This work is being done to help make the rust bindings more safe,
as well as the C code, moving toward the end-goal of allowing us to
put driver structures into read-only memory. We aren't there yet,
but are getting closer.
- minor devres cleanups and fixes found by code inspection
- arch_topology minor changes
- other minor driver core cleanups
All of these have been in linux-next for a very long time with no
reported problems"
* tag 'driver-core-6.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (55 commits)
ARM: sa1100: make match function take a const pointer
sysfs/cpu: Make crash_hotplug attribute world-readable
dio: Have dio_bus_match() callback take a const *
zorro: make match function take a const pointer
driver core: module: make module_[add|remove]_driver take a const *
driver core: make driver_find_device() take a const *
driver core: make driver_[create|remove]_file take a const *
firmware_loader: fix soundness issue in `request_internal`
firmware_loader: annotate doctests as `no_run`
devres: Correct code style for functions that return a pointer type
devres: Initialize an uninitialized struct member
devres: Fix memory leakage caused by driver API devm_free_percpu()
devres: Fix devm_krealloc() wasting memory
driver core: platform: Switch to use kmemdup_array()
driver core: have match() callback in struct bus_type take a const *
MAINTAINERS: add Rust device abstractions to DRIVER CORE
device: rust: improve safety comments
MAINTAINERS: add Danilo as FIRMWARE LOADER maintainer
MAINTAINERS: add Rust FW abstractions to FIRMWARE LOADER
firmware: rust: improve safety comments
...
In the match() callback, the struct device_driver * should not be
changed, so change the function callback to be a const *. This is one
step of many towards making the driver core safe to have struct
device_driver in read-only memory.
Because the match() callback is in all busses, all busses are modified
to handle this properly. This does entail switching some container_of()
calls to container_of_const() to properly handle the constant *.
For some busses, like PCI and USB and HV, the const * is cast away in
the match callback as those busses do want to modify those structures at
this point in time (they have a local lock in the driver structure.)
That will have to be changed in the future if they wish to have their
struct device * in read-only-memory.
Cc: Rafael J. Wysocki <rafael@kernel.org>
Reviewed-by: Alex Elder <elder@kernel.org>
Acked-by: Sumit Garg <sumit.garg@linaro.org>
Link: https://lore.kernel.org/r/2024070136-wrongdoer-busily-01e8@gregkh
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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>
Commit a72bbec70d ("crash: hotplug support for kexec_load()")
introduced a new kexec flag, `KEXEC_UPDATE_ELFCOREHDR`. Kexec tool uses
this flag to indicate to the kernel that it is safe to modify the
elfcorehdr of the kdump image loaded using the kexec_load system call.
However, it is possible that architectures may need to update kexec
segments other then elfcorehdr. For example, FDT (Flatten Device Tree)
on PowerPC. Introducing a new kexec flag for every new kexec segment
may not be a good solution. Hence, a generic kexec flag bit,
`KEXEC_CRASH_HOTPLUG_SUPPORT`, is introduced to share the CPU/Memory
hotplug support intent between the kexec tool and the kernel for the
kexec_load system call.
Now we have two kexec flags that enables crash hotplug support for
kexec_load system call. First is KEXEC_UPDATE_ELFCOREHDR (only used in
x86), and second is KEXEC_CRASH_HOTPLUG_SUPPORT (for all architectures).
To simplify the process of finding and reporting the crash hotplug
support the following changes are introduced.
1. Define arch specific function to process the kexec flags and
determine crash hotplug support
2. Rename the @update_elfcorehdr member of struct kimage to
@hotplug_support and populate it for both kexec_load and
kexec_file_load syscalls, because architecture can update more than
one kexec segment
3. Let generic function crash_check_hotplug_support report hotplug
support for loaded kdump image based on value of @hotplug_support
To bring the x86 crash hotplug support in line with the above points,
the following changes have been made:
- Introduce the arch_crash_hotplug_support function to process kexec
flags and determine crash hotplug support
- Remove the arch_crash_hotplug_[cpu|memory]_support functions
Signed-off-by: Sourabh Jain <sourabhjain@linux.ibm.com>
Acked-by: Baoquan He <bhe@redhat.com>
Acked-by: Hari Bathini <hbathini@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20240326055413.186534-3-sourabhjain@linux.ibm.com
Pull driver core updates from Greg KH:
"Here is the "big" set of driver core and kernfs changes for 6.9-rc1.
Nothing all that crazy here, just some good updates that include:
- automatic attribute group hiding from Dan Williams (he fixed up my
horrible attempt at doing this.)
- kobject lock contention fixes from Eric Dumazet
- driver core cleanups from Andy
- kernfs rcu work from Tejun
- fw_devlink changes to resolve some reported issues
- other minor changes, all details in the shortlog
All of these have been in linux-next for a long time with no reported
issues"
* tag 'driver-core-6.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (28 commits)
device: core: Log warning for devices pending deferred probe on timeout
driver: core: Use dev_* instead of pr_* so device metadata is added
driver: core: Log probe failure as error and with device metadata
of: property: fw_devlink: Add support for "post-init-providers" property
driver core: Add FWLINK_FLAG_IGNORE to completely ignore a fwnode link
driver core: Adds flags param to fwnode_link_add()
debugfs: fix wait/cancellation handling during remove
device property: Don't use "proxy" headers
device property: Move enum dev_dma_attr to fwnode.h
driver core: Move fw_devlink stuff to where it belongs
driver core: Drop unneeded 'extern' keyword in fwnode.h
firmware_loader: Suppress warning on FW_OPT_NO_WARN flag
sysfs:Addresses documentation in sysfs_merge_group and sysfs_unmerge_group.
firmware_loader: introduce __free() cleanup hanler
platform-msi: Remove usage of the deprecated ida_simple_xx() API
sysfs: Introduce DEFINE_SIMPLE_SYSFS_GROUP_VISIBLE()
sysfs: Document new "group visible" helpers
sysfs: Fix crash on empty group attributes array
sysfs: Introduce a mechanism to hide static attribute_groups
sysfs: Introduce a mechanism to hide static attribute_groups
...
Pull MM updates from Andrew Morton:
- Sumanth Korikkar has taught s390 to allocate hotplug-time page frames
from hotplugged memory rather than only from main memory. Series
"implement "memmap on memory" feature on s390".
- More folio conversions from Matthew Wilcox in the series
"Convert memcontrol charge moving to use folios"
"mm: convert mm counter to take a folio"
- Chengming Zhou has optimized zswap's rbtree locking, providing
significant reductions in system time and modest but measurable
reductions in overall runtimes. The series is "mm/zswap: optimize the
scalability of zswap rb-tree".
- Chengming Zhou has also provided the series "mm/zswap: optimize zswap
lru list" which provides measurable runtime benefits in some
swap-intensive situations.
- And Chengming Zhou further optimizes zswap in the series "mm/zswap:
optimize for dynamic zswap_pools". Measured improvements are modest.
- zswap cleanups and simplifications from Yosry Ahmed in the series
"mm: zswap: simplify zswap_swapoff()".
- In the series "Add DAX ABI for memmap_on_memory", Vishal Verma has
contributed several DAX cleanups as well as adding a sysfs tunable to
control the memmap_on_memory setting when the dax device is
hotplugged as system memory.
- Johannes Weiner has added the large series "mm: zswap: cleanups",
which does that.
- More DAMON work from SeongJae Park in the series
"mm/damon: make DAMON debugfs interface deprecation unignorable"
"selftests/damon: add more tests for core functionalities and corner cases"
"Docs/mm/damon: misc readability improvements"
"mm/damon: let DAMOS feeds and tame/auto-tune itself"
- In the series "mm/mempolicy: weighted interleave mempolicy and sysfs
extension" Rakie Kim has developed a new mempolicy interleaving
policy wherein we allocate memory across nodes in a weighted fashion
rather than uniformly. This is beneficial in heterogeneous memory
environments appearing with CXL.
- Christophe Leroy has contributed some cleanup and consolidation work
against the ARM pagetable dumping code in the series "mm: ptdump:
Refactor CONFIG_DEBUG_WX and check_wx_pages debugfs attribute".
- Luis Chamberlain has added some additional xarray selftesting in the
series "test_xarray: advanced API multi-index tests".
- Muhammad Usama Anjum has reworked the selftest code to make its
human-readable output conform to the TAP ("Test Anything Protocol")
format. Amongst other things, this opens up the use of third-party
tools to parse and process out selftesting results.
- Ryan Roberts has added fork()-time PTE batching of THP ptes in the
series "mm/memory: optimize fork() with PTE-mapped THP". Mainly
targeted at arm64, this significantly speeds up fork() when the
process has a large number of pte-mapped folios.
- David Hildenbrand also gets in on the THP pte batching game in his
series "mm/memory: optimize unmap/zap with PTE-mapped THP". It
implements batching during munmap() and other pte teardown
situations. The microbenchmark improvements are nice.
- And in the series "Transparent Contiguous PTEs for User Mappings"
Ryan Roberts further utilizes arm's pte's contiguous bit ("contpte
mappings"). Kernel build times on arm64 improved nicely. Ryan's
series "Address some contpte nits" provides some followup work.
- In the series "mm/hugetlb: Restore the reservation" Breno Leitao has
fixed an obscure hugetlb race which was causing unnecessary page
faults. He has also added a reproducer under the selftest code.
- In the series "selftests/mm: Output cleanups for the compaction
test", Mark Brown did what the title claims.
- Kinsey Ho has added the series "mm/mglru: code cleanup and
refactoring".
- Even more zswap material from Nhat Pham. The series "fix and extend
zswap kselftests" does as claimed.
- In the series "Introduce cpu_dcache_is_aliasing() to fix DAX
regression" Mathieu Desnoyers has cleaned up and fixed rather a mess
in our handling of DAX on archiecctures which have virtually aliasing
data caches. The arm architecture is the main beneficiary.
- Lokesh Gidra's series "per-vma locks in userfaultfd" provides
dramatic improvements in worst-case mmap_lock hold times during
certain userfaultfd operations.
- Some page_owner enhancements and maintenance work from Oscar Salvador
in his series
"page_owner: print stacks and their outstanding allocations"
"page_owner: Fixup and cleanup"
- Uladzislau Rezki has contributed some vmalloc scalability
improvements in his series "Mitigate a vmap lock contention". It
realizes a 12x improvement for a certain microbenchmark.
- Some kexec/crash cleanup work from Baoquan He in the series "Split
crash out from kexec and clean up related config items".
- Some zsmalloc maintenance work from Chengming Zhou in the series
"mm/zsmalloc: fix and optimize objects/page migration"
"mm/zsmalloc: some cleanup for get/set_zspage_mapping()"
- Zi Yan has taught the MM to perform compaction on folios larger than
order=0. This a step along the path to implementaton of the merging
of large anonymous folios. The series is named "Enable >0 order folio
memory compaction".
- Christoph Hellwig has done quite a lot of cleanup work in the
pagecache writeback code in his series "convert write_cache_pages()
to an iterator".
- Some modest hugetlb cleanups and speedups in Vishal Moola's series
"Handle hugetlb faults under the VMA lock".
- Zi Yan has changed the page splitting code so we can split huge pages
into sizes other than order-0 to better utilize large folios. The
series is named "Split a folio to any lower order folios".
- David Hildenbrand has contributed the series "mm: remove
total_mapcount()", a cleanup.
- Matthew Wilcox has sought to improve the performance of bulk memory
freeing in his series "Rearrange batched folio freeing".
- Gang Li's series "hugetlb: parallelize hugetlb page init on boot"
provides large improvements in bootup times on large machines which
are configured to use large numbers of hugetlb pages.
- Matthew Wilcox's series "PageFlags cleanups" does that.
- Qi Zheng's series "minor fixes and supplement for ptdesc" does that
also. S390 is affected.
- Cleanups to our pagemap utility functions from Peter Xu in his series
"mm/treewide: Replace pXd_large() with pXd_leaf()".
- Nico Pache has fixed a few things with our hugepage selftests in his
series "selftests/mm: Improve Hugepage Test Handling in MM
Selftests".
- Also, of course, many singleton patches to many things. Please see
the individual changelogs for details.
* tag 'mm-stable-2024-03-13-20-04' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (435 commits)
mm/zswap: remove the memcpy if acomp is not sleepable
crypto: introduce: acomp_is_async to expose if comp drivers might sleep
memtest: use {READ,WRITE}_ONCE in memory scanning
mm: prohibit the last subpage from reusing the entire large folio
mm: recover pud_leaf() definitions in nopmd case
selftests/mm: skip the hugetlb-madvise tests on unmet hugepage requirements
selftests/mm: skip uffd hugetlb tests with insufficient hugepages
selftests/mm: dont fail testsuite due to a lack of hugepages
mm/huge_memory: skip invalid debugfs new_order input for folio split
mm/huge_memory: check new folio order when split a folio
mm, vmscan: retry kswapd's priority loop with cache_trim_mode off on failure
mm: add an explicit smp_wmb() to UFFDIO_CONTINUE
mm: fix list corruption in put_pages_list
mm: remove folio from deferred split list before uncharging it
filemap: avoid unnecessary major faults in filemap_fault()
mm,page_owner: drop unnecessary check
mm,page_owner: check for null stack_record before bumping its refcount
mm: swap: fix race between free_swap_and_cache() and swapoff()
mm/treewide: align up pXd_leaf() retval across archs
mm/treewide: drop pXd_large()
...
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>
Currently, KEXEC_CORE select CRASH_CORE automatically because crash codes
need be built in to avoid compiling error when building kexec code even
though the crash dumping functionality is not enabled. E.g
--------------------
CONFIG_CRASH_CORE=y
CONFIG_KEXEC_CORE=y
CONFIG_KEXEC=y
CONFIG_KEXEC_FILE=y
---------------------
After splitting out crashkernel reservation code and vmcoreinfo exporting
code, there's only crash related code left in kernel/crash_core.c. Now
move crash related codes from kexec_core.c to crash_core.c and only build it
in when CONFIG_CRASH_DUMP=y.
And also wrap up crash codes inside CONFIG_CRASH_DUMP ifdeffery scope,
or replace inappropriate CONFIG_KEXEC_CORE ifdef with CONFIG_CRASH_DUMP
ifdef in generic kernel files.
With these changes, crash_core codes are abstracted from kexec codes and
can be disabled at all if only kexec reboot feature is wanted.
Link: https://lkml.kernel.org/r/20240124051254.67105-5-bhe@redhat.com
Signed-off-by: Baoquan He <bhe@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Hari Bathini <hbathini@linux.ibm.com>
Cc: Pingfan Liu <piliu@redhat.com>
Cc: Klara Modin <klarasmodin@gmail.com>
Cc: Michael Kelley <mhklinux@outlook.com>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Yang Li <yang.lee@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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()
...
After commit 88a6f89944 ("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: 88a6f89944 ("crash: memory and CPU hotplug sysfs attributes")
Signed-off-by: Baoquan He <bhe@redhat.com>
Tested-by: Ignat Korchagin <ignat@cloudflare.com> [compile-time only]
Tested-by: Alexander Gordeev <agordeev@linux.ibm.com>
Reviewed-by: Eric DeVolder <eric_devolder@yahoo.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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 <james.morse@arm.com>
Reviewed-by: "Russell King (Oracle)" <rmk+kernel@armlinux.org.uk>
Reviewed-by: Shaoqin Huang <shahuang@redhat.com>
Signed-off-by: "Russell King (Oracle)" <rmk+kernel@armlinux.org.uk>
Reviewed-by: Gavin Shan <gshan@redhat.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/E1r5R3W-00CszU-GM@rmk-PC.armlinux.org.uk
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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 <james.morse@arm.com>
Reviewed-by: Shaoqin Huang <shahuang@redhat.com>
Reviewed-by: Gavin Shan <gshan@redhat.com>
Signed-off-by: "Russell King (Oracle)" <rmk+kernel@armlinux.org.uk>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/E1r5R3B-00Csz6-Uh@rmk-PC.armlinux.org.uk
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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 <james.morse@arm.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Gavin Shan <gshan@redhat.com>
Signed-off-by: "Russell King (Oracle)" <rmk+kernel@armlinux.org.uk>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/E1r5R36-00Csz0-Px@rmk-PC.armlinux.org.uk
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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
...
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
...
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>
In
6524c798b7 ("driver core: cpu: Make cpu_show_not_affected() static")
I fat-fingered the name of cpu_show_gds(). Usually, I'd rebase but since
those are extraordinary embargoed times, the commit above was already
pulled into another tree so no no.
Therefore, fix it ontop.
Fixes: 6524c798b7 ("driver core: cpu: Make cpu_show_not_affected() static")
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20230811095831.27513-1-bp@alien8.de
