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401 Commits
| Author | SHA1 | Message | Date | |
|---|---|---|---|---|
Linus Torvalds
|
d30e51aa7b |
slab updates for 6.8
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Merge tag 'slab-for-6.8' of git://git.kernel.org/pub/scm/linux/kernel/git/vbabka/slab
Pull slab updates from Vlastimil Babka:
- SLUB: delayed freezing of CPU partial slabs (Chengming Zhou)
Freezing is an operation involving double_cmpxchg() that makes a slab
exclusive for a particular CPU. Chengming noticed that we use it also
in situations where we are not yet installing the slab as the CPU
slab, because freezing also indicates that the slab is not on the
shared list. This results in redundant freeze/unfreeze operation and
can be avoided by marking separately the shared list presence by
reusing the PG_workingset flag.
This approach neatly avoids the issues described in
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Vlastimil Babka
|
70da1d01ed |
cpu/hotplug: remove CPUHP_SLAB_PREPARE hooks
The CPUHP_SLAB_PREPARE hooks are only used by SLAB which is removed. SLUB defines them as NULL, so we can remove those altogether. Acked-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: David Rientjes <rientjes@google.com> Tested-by: David Rientjes <rientjes@google.com> Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com> Tested-by: Hyeonggon Yoo <42.hyeyoo@gmail.com> Signed-off-by: Vlastimil Babka <vbabka@suse.cz> |
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Linus Torvalds
|
b0014556a2 |
- Do the push of pending hrtimers away from a CPU which is being
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Thomas Gleixner
|
5c0930ccaa |
hrtimers: Push pending hrtimers away from outgoing CPU earlier
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Linus Torvalds
|
1e0c505e13 |
asm-generic updates for v6.7
The ia64 architecture gets its well-earned retirement as planned, now that there is one last (mostly) working release that will be maintained as an LTS kernel. The architecture specific system call tables are updated for the added map_shadow_stack() syscall and to remove references to the long-gone sys_lookup_dcookie() syscall. -----BEGIN PGP SIGNATURE----- iQIzBAABCgAdFiEEiK/NIGsWEZVxh/FrYKtH/8kJUicFAmVC40IACgkQYKtH/8kJ Uidhmw/9EX+aWSXGoObJ3fngaNSMw+PmrEuP8qEKBHxfKHcCdX3hc451Oh4GlhaQ tru91pPwgNvN2/rfoKusxT+V4PemGIzfNni/04rp+P0kvmdw5otQ2yNhsQNsfVmq XGWvkxF4P2GO6bkjjfR/1dDq7GtlyXtwwPDKeLbYb6TnJOZjtx+EAN27kkfSn1Ms R4Sa3zJ+DfHUmHL5S9g+7UD/CZ5GfKNmIskI4Mz5GsfoUz/0iiU+Bge/9sdcdSJQ kmbLy5YnVzfooLZ3TQmBFsO3iAMWb0s/mDdtyhqhTVmTUshLolkPYyKnPFvdupyv shXcpEST2XJNeaDRnL2K4zSCdxdbnCZHDpjfl9wfioBg7I8NfhXKpf1jYZHH1de4 LXq8ndEFEOVQw/zSpYWfQq1sux8Jiqr+UK/ukbVeFWiGGIUs91gEWtPAf8T0AZo9 ujkJvaWGl98O1g5wmBu0/dAR6QcFJMDfVwbmlIFpU8O+MEaz6X8mM+O5/T0IyTcD eMbAUjj4uYcU7ihKzHEv/0SS9Of38kzff67CLN5k8wOP/9NlaGZ78o1bVle9b52A BdhrsAefFiWHp1jT6Y9Rg4HOO/TguQ9e6EWSKOYFulsiLH9LEFaB9RwZLeLytV0W vlAgY9rUW77g1OJcb7DoNv33nRFuxsKqsnz3DEIXtgozo9CzbYI= =H1vH -----END PGP SIGNATURE----- Merge tag 'asm-generic-6.7' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic Pull ia64 removal and asm-generic updates from Arnd Bergmann: - The ia64 architecture gets its well-earned retirement as planned, now that there is one last (mostly) working release that will be maintained as an LTS kernel. - The architecture specific system call tables are updated for the added map_shadow_stack() syscall and to remove references to the long-gone sys_lookup_dcookie() syscall. * tag 'asm-generic-6.7' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic: hexagon: Remove unusable symbols from the ptrace.h uapi asm-generic: Fix spelling of architecture arch: Reserve map_shadow_stack() syscall number for all architectures syscalls: Cleanup references to sys_lookup_dcookie() Documentation: Drop or replace remaining mentions of IA64 lib/raid6: Drop IA64 support Documentation: Drop IA64 from feature descriptions kernel: Drop IA64 support from sig_fault handlers arch: Remove Itanium (IA-64) architecture |
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Linus Torvalds
|
2656821f1f |
RCU pull request for v6.7
This pull request contains the following branches:
rcu/torture: RCU torture, locktorture and generic torture infrastructure
updates that include various fixes, cleanups and consolidations.
Among the user visible things, ftrace dumps can now be found into
their own file, and module parameters get better documented and
reported on dumps.
rcu/fixes: Generic and misc fixes all over the place. Some highlights:
* Hotplug handling has seen some light cleanups and comments.
* An RCU barrier can now be triggered through sysfs to serialize
memory stress testing and avoid OOM.
* Object information is now dumped in case of invalid callback
invocation.
* Also various SRCU issues, too hard to trigger to deserve urgent
pull requests, have been fixed.
rcu/docs: RCU documentation updates
rcu/refscale: RCU reference scalability test minor fixes and doc
improvements.
rcu/tasks: RCU tasks minor fixes
rcu/stall: Stall detection updates. Introduce RCU CPU Stall notifiers
that allows a subsystem to provide informations to help debugging.
Also cure some false positive stalls.
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Merge tag 'rcu-next-v6.7' of git://git.kernel.org/pub/scm/linux/kernel/git/frederic/linux-dynticks
Pull RCU updates from Frederic Weisbecker:
- RCU torture, locktorture and generic torture infrastructure updates
that include various fixes, cleanups and consolidations.
Among the user visible things, ftrace dumps can now be found into
their own file, and module parameters get better documented and
reported on dumps.
- Generic and misc fixes all over the place. Some highlights:
* Hotplug handling has seen some light cleanups and comments
* An RCU barrier can now be triggered through sysfs to serialize
memory stress testing and avoid OOM
* Object information is now dumped in case of invalid callback
invocation
* Also various SRCU issues, too hard to trigger to deserve urgent
pull requests, have been fixed
- RCU documentation updates
- RCU reference scalability test minor fixes and doc improvements.
- RCU tasks minor fixes
- Stall detection updates. Introduce RCU CPU Stall notifiers that
allows a subsystem to provide informations to help debugging. Also
cure some false positive stalls.
* tag 'rcu-next-v6.7' of git://git.kernel.org/pub/scm/linux/kernel/git/frederic/linux-dynticks: (56 commits)
srcu: Only accelerate on enqueue time
locktorture: Check the correct variable for allocation failure
srcu: Fix callbacks acceleration mishandling
rcu: Comment why callbacks migration can't wait for CPUHP_RCUTREE_PREP
rcu: Standardize explicit CPU-hotplug calls
rcu: Conditionally build CPU-hotplug teardown callbacks
rcu: Remove references to rcu_migrate_callbacks() from diagrams
rcu: Assume rcu_report_dead() is always called locally
rcu: Assume IRQS disabled from rcu_report_dead()
rcu: Use rcu_segcblist_segempty() instead of open coding it
rcu: kmemleak: Ignore kmemleak false positives when RCU-freeing objects
srcu: Fix srcu_struct node grpmask overflow on 64-bit systems
torture: Convert parse-console.sh to mktemp
rcutorture: Traverse possible cpu to set maxcpu in rcu_nocb_toggle()
rcutorture: Replace schedule_timeout*() 1-jiffy waits with HZ/20
torture: Add kvm.sh --debug-info argument
locktorture: Rename readers_bind/writers_bind to bind_readers/bind_writers
doc: Catch-up update for locktorture module parameters
locktorture: Add call_rcu_chains module parameter
locktorture: Add new module parameters to lock_torture_print_module_parms()
...
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|
Linus Torvalds
|
eb55307e67 |
X86 core code updates:
- Limit the hardcoded topology quirk for Hygon CPUs to those which have a
model ID less than 4. The newer models have the topology CPUID leaf 0xB
correctly implemented and are not affected.
- Make SMT control more robust against enumeration failures
SMT control was added to allow controlling SMT at boottime or
runtime. The primary purpose was to provide a simple mechanism to
disable SMT in the light of speculation attack vectors.
It turned out that the code is sensible to enumeration failures and
worked only by chance for XEN/PV. XEN/PV has no real APIC enumeration
which means the primary thread mask is not set up correctly. By chance
a XEN/PV boot ends up with smp_num_siblings == 2, which makes the
hotplug control stay at its default value "enabled". So the mask is
never evaluated.
The ongoing rework of the topology evaluation caused XEN/PV to end up
with smp_num_siblings == 1, which sets the SMT control to "not
supported" and the empty primary thread mask causes the hotplug core to
deny the bringup of the APS.
Make the decision logic more robust and take 'not supported' and 'not
implemented' into account for the decision whether a CPU should be
booted or not.
- Fake primary thread mask for XEN/PV
Pretend that all XEN/PV vCPUs are primary threads, which makes the
usage of the primary thread mask valid on XEN/PV. That is consistent
with because all of the topology information on XEN/PV is fake or even
non-existent.
- Encapsulate topology information in cpuinfo_x86
Move the randomly scattered topology data into a separate data
structure for readability and as a preparatory step for the topology
evaluation overhaul.
- Consolidate APIC ID data type to u32
It's fixed width hardware data and not randomly u16, int, unsigned long
or whatever developers decided to use.
- Cure the abuse of cpuinfo for persisting logical IDs.
Per CPU cpuinfo is used to persist the logical package and die
IDs. That's really not the right place simply because cpuinfo is
subject to be reinitialized when a CPU goes through an offline/online
cycle.
Use separate per CPU data for the persisting to enable the further
topology management rework. It will be removed once the new topology
management is in place.
- Provide a debug interface for inspecting topology information
Useful in general and extremly helpful for validating the topology
management rework in terms of correctness or "bug" compatibility.
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Merge tag 'x86-core-2023-10-29-v2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 core updates from Thomas Gleixner:
- Limit the hardcoded topology quirk for Hygon CPUs to those which have
a model ID less than 4.
The newer models have the topology CPUID leaf 0xB correctly
implemented and are not affected.
- Make SMT control more robust against enumeration failures
SMT control was added to allow controlling SMT at boottime or
runtime. The primary purpose was to provide a simple mechanism to
disable SMT in the light of speculation attack vectors.
It turned out that the code is sensible to enumeration failures and
worked only by chance for XEN/PV. XEN/PV has no real APIC enumeration
which means the primary thread mask is not set up correctly. By
chance a XEN/PV boot ends up with smp_num_siblings == 2, which makes
the hotplug control stay at its default value "enabled". So the mask
is never evaluated.
The ongoing rework of the topology evaluation caused XEN/PV to end up
with smp_num_siblings == 1, which sets the SMT control to "not
supported" and the empty primary thread mask causes the hotplug core
to deny the bringup of the APS.
Make the decision logic more robust and take 'not supported' and 'not
implemented' into account for the decision whether a CPU should be
booted or not.
- Fake primary thread mask for XEN/PV
Pretend that all XEN/PV vCPUs are primary threads, which makes the
usage of the primary thread mask valid on XEN/PV. That is consistent
with because all of the topology information on XEN/PV is fake or
even non-existent.
- Encapsulate topology information in cpuinfo_x86
Move the randomly scattered topology data into a separate data
structure for readability and as a preparatory step for the topology
evaluation overhaul.
- Consolidate APIC ID data type to u32
It's fixed width hardware data and not randomly u16, int, unsigned
long or whatever developers decided to use.
- Cure the abuse of cpuinfo for persisting logical IDs.
Per CPU cpuinfo is used to persist the logical package and die IDs.
That's really not the right place simply because cpuinfo is subject
to be reinitialized when a CPU goes through an offline/online cycle.
Use separate per CPU data for the persisting to enable the further
topology management rework. It will be removed once the new topology
management is in place.
- Provide a debug interface for inspecting topology information
Useful in general and extremly helpful for validating the topology
management rework in terms of correctness or "bug" compatibility.
* tag 'x86-core-2023-10-29-v2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (23 commits)
x86/apic, x86/hyperv: Use u32 in hv_snp_boot_ap() too
x86/cpu: Provide debug interface
x86/cpu/topology: Cure the abuse of cpuinfo for persisting logical ids
x86/apic: Use u32 for wakeup_secondary_cpu[_64]()
x86/apic: Use u32 for [gs]et_apic_id()
x86/apic: Use u32 for phys_pkg_id()
x86/apic: Use u32 for cpu_present_to_apicid()
x86/apic: Use u32 for check_apicid_used()
x86/apic: Use u32 for APIC IDs in global data
x86/apic: Use BAD_APICID consistently
x86/cpu: Move cpu_l[l2]c_id into topology info
x86/cpu: Move logical package and die IDs into topology info
x86/cpu: Remove pointless evaluation of x86_coreid_bits
x86/cpu: Move cu_id into topology info
x86/cpu: Move cpu_core_id into topology info
hwmon: (fam15h_power) Use topology_core_id()
scsi: lpfc: Use topology_core_id()
x86/cpu: Move cpu_die_id into topology info
x86/cpu: Move phys_proc_id into topology info
x86/cpu: Encapsulate topology information in cpuinfo_x86
...
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Ran Xiaokai
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38685e2a04 |
cpu/hotplug: Don't offline the last non-isolated CPU
If a system has isolated CPUs via the "isolcpus=" command line parameter,
then an attempt to offline the last housekeeping CPU will result in a
WARN_ON() when rebuilding the scheduler domains and a subsequent panic due
to and unhandled empty CPU mas in partition_sched_domains_locked().
cpuset_hotplug_workfn()
rebuild_sched_domains_locked()
ndoms = generate_sched_domains(&doms, &attr);
cpumask_and(doms[0], top_cpuset.effective_cpus, housekeeping_cpumask(HK_FLAG_DOMAIN));
Thus results in an empty CPU mask which triggers the warning and then the
subsequent crash:
WARNING: CPU: 4 PID: 80 at kernel/sched/topology.c:2366 build_sched_domains+0x120c/0x1408
Call trace:
build_sched_domains+0x120c/0x1408
partition_sched_domains_locked+0x234/0x880
rebuild_sched_domains_locked+0x37c/0x798
rebuild_sched_domains+0x30/0x58
cpuset_hotplug_workfn+0x2a8/0x930
Unable to handle kernel paging request at virtual address fffe80027ab37080
partition_sched_domains_locked+0x318/0x880
rebuild_sched_domains_locked+0x37c/0x798
Aside of the resulting crash, it does not make any sense to offline the last
last housekeeping CPU.
Prevent this by masking out the non-housekeeping CPUs when selecting a
target CPU for initiating the CPU unplug operation via the work queue.
Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ran Xiaokai <ran.xiaokai@zte.com.cn>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/202310171709530660462@zte.com.cn
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Thomas Gleixner
|
d91bdd96b5 |
cpu/SMT: Make SMT control more robust against enumeration failures
The SMT control mechanism got added as speculation attack vector
mitigation. The implemented logic relies on the primary thread mask to
be set up properly.
This turns out to be an issue with XEN/PV guests because their CPU hotplug
mechanics do not enumerate APICs and therefore the mask is never correctly
populated.
This went unnoticed so far because by chance XEN/PV ends up with
smp_num_siblings == 2. So smt_hotplug_control stays at its default value
CPU_SMT_ENABLED and the primary thread mask is never evaluated in the
context of CPU hotplug.
This stopped "working" with the upcoming overhaul of the topology
evaluation which legitimately provides a fake topology for XEN/PV. That
sets smp_num_siblings to 1, which causes the core CPU hot-plug core to
refuse to bring up the APs.
This happens because smt_hotplug_control is set to CPU_SMT_NOT_SUPPORTED
which causes cpu_smt_allowed() to evaluate the unpopulated primary thread
mask with the conclusion that all non-boot CPUs are not valid to be
plugged.
Make cpu_smt_allowed() more robust and take CPU_SMT_NOT_SUPPORTED and
CPU_SMT_NOT_IMPLEMENTED into account. Rename it to cpu_bootable() while at
it as that makes it more clear what the function is about.
The primary mask issue on x86 XEN/PV needs to be addressed separately as
there are users outside of the CPU hotplug code too.
Fixes:
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||
Frederic Weisbecker
|
a28ab03b49 |
rcu: Comment why callbacks migration can't wait for CPUHP_RCUTREE_PREP
The callbacks migration is performed through an explicit call from
the hotplug control CPU right after the death of the target CPU and
before proceeding with the CPUHP_ teardown functions.
This is unusual but necessary and yet uncommented. Summarize the reason
as explained in the changelog of:
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Frederic Weisbecker
|
448e9f34d9 |
rcu: Standardize explicit CPU-hotplug calls
rcu_report_dead() and rcutree_migrate_callbacks() have their headers in rcupdate.h while those are pure rcutree calls, like the other CPU-hotplug functions. Also rcu_cpu_starting() and rcu_report_dead() have different naming conventions while they mirror each other's effects. Fix the headers and propose a naming that relates both functions and aligns with the prefix of other rcutree CPU-hotplug functions. Reviewed-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Frederic Weisbecker <frederic@kernel.org> |
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Frederic Weisbecker
|
c964c1f5ee |
rcu: Assume rcu_report_dead() is always called locally
rcu_report_dead() has to be called locally by the CPU that is going to exit the RCU state machine. Passing a cpu argument here is error-prone and leaves the possibility for a racy remote call. Use local access instead. Reviewed-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Frederic Weisbecker <frederic@kernel.org> |
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Ard Biesheuvel
|
cf8e865810 |
arch: Remove Itanium (IA-64) architecture
The Itanium architecture is obsolete, and an informal survey [0] reveals that any residual use of Itanium hardware in production is mostly HP-UX or OpenVMS based. The use of Linux on Itanium appears to be limited to enthusiasts that occasionally boot a fresh Linux kernel to see whether things are still working as intended, and perhaps to churn out some distro packages that are rarely used in practice. None of the original companies behind Itanium still produce or support any hardware or software for the architecture, and it is listed as 'Orphaned' in the MAINTAINERS file, as apparently, none of the engineers that contributed on behalf of those companies (nor anyone else, for that matter) have been willing to support or maintain the architecture upstream or even be responsible for applying the odd fix. The Intel firmware team removed all IA-64 support from the Tianocore/EDK2 reference implementation of EFI in 2018. (Itanium is the original architecture for which EFI was developed, and the way Linux supports it deviates significantly from other architectures.) Some distros, such as Debian and Gentoo, still maintain [unofficial] ia64 ports, but many have dropped support years ago. While the argument is being made [1] that there is a 'for the common good' angle to being able to build and run existing projects such as the Grid Community Toolkit [2] on Itanium for interoperability testing, the fact remains that none of those projects are known to be deployed on Linux/ia64, and very few people actually have access to such a system in the first place. Even if there were ways imaginable in which Linux/ia64 could be put to good use today, what matters is whether anyone is actually doing that, and this does not appear to be the case. There are no emulators widely available, and so boot testing Itanium is generally infeasible for ordinary contributors. GCC still supports IA-64 but its compile farm [3] no longer has any IA-64 machines. GLIBC would like to get rid of IA-64 [4] too because it would permit some overdue code cleanups. In summary, the benefits to the ecosystem of having IA-64 be part of it are mostly theoretical, whereas the maintenance overhead of keeping it supported is real. So let's rip off the band aid, and remove the IA-64 arch code entirely. This follows the timeline proposed by the Debian/ia64 maintainer [5], which removes support in a controlled manner, leaving IA-64 in a known good state in the most recent LTS release. Other projects will follow once the kernel support is removed. [0] https://lore.kernel.org/all/CAMj1kXFCMh_578jniKpUtx_j8ByHnt=s7S+yQ+vGbKt9ud7+kQ@mail.gmail.com/ [1] https://lore.kernel.org/all/0075883c-7c51-00f5-2c2d-5119c1820410@web.de/ [2] https://gridcf.org/gct-docs/latest/index.html [3] https://cfarm.tetaneutral.net/machines/list/ [4] https://lore.kernel.org/all/87bkiilpc4.fsf@mid.deneb.enyo.de/ [5] https://lore.kernel.org/all/ff58a3e76e5102c94bb5946d99187b358def688a.camel@physik.fu-berlin.de/ Acked-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Ard Biesheuvel <ardb@kernel.org> |
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Thomas Gleixner
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2b8272ff4a |
cpu/hotplug: Prevent self deadlock on CPU hot-unplug
Xiongfeng reported and debugged a self deadlock of the task which initiates
and controls a CPU hot-unplug operation vs. the CFS bandwidth timer.
CPU1 CPU2
T1 sets cfs_quota
starts hrtimer cfs_bandwidth 'period_timer'
T1 is migrated to CPU2
T1 initiates offlining of CPU1
Hotplug operation starts
...
'period_timer' expires and is re-enqueued on CPU1
...
take_cpu_down()
CPU1 shuts down and does not handle timers
anymore. They have to be migrated in the
post dead hotplug steps by the control task.
T1 runs the post dead offline operation
T1 is scheduled out
T1 waits for 'period_timer' to expire
T1 waits there forever if it is scheduled out before it can execute the hrtimer
offline callback hrtimers_dead_cpu().
Cure this by delegating the hotplug control operation to a worker thread on
an online CPU. This takes the initiating user space task, which might be
affected by the bandwidth timer, completely out of the picture.
Reported-by: Xiongfeng Wang <wangxiongfeng2@huawei.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Yu Liao <liaoyu15@huawei.com>
Acked-by: Vincent Guittot <vincent.guittot@linaro.org>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/lkml/8e785777-03aa-99e1-d20e-e956f5685be6@huawei.com
Link: https://lore.kernel.org/r/87h6oqdq0i.ffs@tglx
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Zhang Rui
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52b38b7ad5 |
cpu/SMT: Fix cpu_smt_possible() comment
Commit
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Michael Ellerman
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7f48405c3c |
cpu/SMT: Allow enabling partial SMT states via sysfs
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 |
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Michael Ellerman
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38253464bc |
cpu/SMT: Create topology_smt_thread_allowed()
Some architectures allows partial SMT states, i.e. when not all SMT threads are brought online. To support that, add an architecture helper which checks whether a given CPU is allowed to be brought online depending on how many SMT threads are currently enabled. Since this is only applicable to architecture supporting partial SMT, only these architectures should select the new configuration variable CONFIG_SMT_NUM_THREADS_DYNAMIC. For the other architectures, not supporting the partial SMT states, there is no need to define topology_cpu_smt_allowed(), the generic code assumed that all the threads are allowed or only the primary ones. Call the helper from cpu_smt_enable(), and cpu_smt_allowed() when SMT is enabled, to check if the particular thread should be onlined. Notably, also call it from cpu_smt_disable() if CPU_SMT_ENABLED, to allow offlining some threads to move from a higher to lower number of threads online. [ ldufour: Slightly reword the commit's description ] [ ldufour: Introduce CONFIG_SMT_NUM_THREADS_DYNAMIC ] Suggested-by: Thomas Gleixner <tglx@linutronix.de> 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/20230705145143.40545-7-ldufour@linux.ibm.com |
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Laurent Dufour
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91b4a7dbfe |
cpu/SMT: Remove topology_smt_supported()
Since the maximum number of threads is now passed to cpu_smt_set_num_threads(), checking that value is enough to know whether SMT is supported. Suggested-by: Thomas Gleixner <tglx@linutronix.de> 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/20230705145143.40545-6-ldufour@linux.ibm.com |
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Michael Ellerman
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447ae4ac41 |
cpu/SMT: Store the current/max number of threads
Some architectures allow partial SMT states at boot time, ie. when not all SMT threads are brought online. To support that the SMT code needs to know the maximum number of SMT threads, and also the currently configured number. The architecture code knows the max number of threads, so have the architecture code pass that value to cpu_smt_set_num_threads(). Note that although topology_max_smt_threads() exists, it is not configured early enough to be used here. As architecture, like PowerPC, allows the threads number to be set through the kernel command line, also pass that value. [ ldufour: Slightly reword the commit message ] [ ldufour: Rename cpu_smt_check_topology and add a num_threads argument ] 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/20230705145143.40545-5-ldufour@linux.ibm.com |
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Michael Ellerman
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c53361ce7d |
cpu/SMT: Move smt/control simple exit cases earlier
Move the simple exit cases, i.e. those which don't depend on the value written, earlier in the function. That makes it clearer that regardless of the input those states cannot be transitioned out of. That does have a user-visible effect, in that the error returned will now always be EPERM/ENODEV for those states, regardless of the value written. Previously writing an invalid value would return EINVAL even when in those states. Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Zhang Rui <rui.zhang@intel.com> Link: https://lore.kernel.org/r/20230705145143.40545-4-ldufour@linux.ibm.com |
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Michael Ellerman
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3f9169196b |
cpu/SMT: Move SMT prototypes into cpu_smt.h
In order to export the cpuhp_smt_control enum as part of the interface between generic and architecture code, the architecture code needs to include asm/topology.h. But that leads to circular header dependencies. So split the enum and related declarations into a separate header. [ ldufour: Reworded the commit's description ] 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/20230705145143.40545-3-ldufour@linux.ibm.com |
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Laurent Dufour
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7a4dcb4a5d |
cpu/hotplug: Remove dependancy against cpu_primary_thread_mask
The commit
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Thomas Gleixner
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06c6796e03 |
cpu/hotplug: Fix off by one in cpuhp_bringup_mask()
cpuhp_bringup_mask() iterates over a cpumask and starts all present CPUs up
to a caller provided upper limit.
The limit variable is decremented and checked for 0 before invoking
cpu_up(), which is obviously off by one and prevents the bringup of the
last CPU when the limit is equal to the number of present CPUs.
Move the decrement and check after the cpu_up() invocation.
Fixes:
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Thomas Gleixner
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18415f33e2 |
cpu/hotplug: Allow "parallel" bringup up to CPUHP_BP_KICK_AP_STATE
There is often significant latency in the early stages of CPU bringup, and time is wasted by waking each CPU (e.g. with SIPI/INIT/INIT on x86) and then waiting for it to respond before moving on to the next. Allow a platform to enable parallel setup which brings all to be onlined CPUs up to the CPUHP_BP_KICK_AP state. While this state advancement on the control CPU (BP) is single-threaded the important part is the last state CPUHP_BP_KICK_AP which wakes the to be onlined CPUs up. This allows the CPUs to run up to the first sychronization point cpuhp_ap_sync_alive() where they wait for the control CPU to release them one by one for the full onlining procedure. This parallelism depends on the CPU hotplug core sync mechanism which ensures that the parallel brought up CPUs wait for release before touching any state which would make the CPU visible to anything outside the hotplug control mechanism. To handle the SMT constraints of X86 correctly the bringup happens in two iterations when CONFIG_HOTPLUG_SMT is enabled. The control CPU brings up the primary SMT threads of each core first, which can load the microcode without the need to rendevouz with the thread siblings. Once that's completed it brings up the secondary SMT threads. Co-developed-by: David Woodhouse <dwmw@amazon.co.uk> Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Tested-by: Michael Kelley <mikelley@microsoft.com> Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name> Tested-by: Helge Deller <deller@gmx.de> # parisc Tested-by: Guilherme G. Piccoli <gpiccoli@igalia.com> # Steam Deck Link: https://lore.kernel.org/r/20230512205257.240231377@linutronix.de |
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Thomas Gleixner
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a631be92b9 |
cpu/hotplug: Provide a split up CPUHP_BRINGUP mechanism
The bring up logic of a to be onlined CPU consists of several parts, which
are considered to be a single hotplug state:
1) Control CPU issues the wake-up
2) To be onlined CPU starts up, does the minimal initialization,
reports to be alive and waits for release into the complete bring-up.
3) Control CPU waits for the alive report and releases the upcoming CPU
for the complete bring-up.
Allow to split this into two states:
1) Control CPU issues the wake-up
After that the to be onlined CPU starts up, does the minimal
initialization, reports to be alive and waits for release into the
full bring-up. As this can run after the control CPU dropped the
hotplug locks the code which is executed on the AP before it reports
alive has to be carefully audited to not violate any of the hotplug
constraints, especially not modifying any of the various cpumasks.
This is really only meant to avoid waiting for the AP to react on the
wake-up. Of course an architecture can move strict CPU related setup
functionality, e.g. microcode loading, with care before the
synchronization point to save further pointless waiting time.
2) Control CPU waits for the alive report and releases the upcoming CPU
for the complete bring-up.
This allows that the two states can be split up to run all to be onlined
CPUs up to state #1 on the control CPU and then at a later point run state
#2. This spares some of the latencies of the full serialized per CPU
bringup by avoiding the per CPU wakeup/wait serialization. The assumption
is that the first AP already waits when the last AP has been woken up. This
obvioulsy depends on the hardware latencies and depending on the timings
this might still not completely eliminate all wait scenarios.
This split is just a preparatory step for enabling the parallel bringup
later. The boot time bringup is still fully serialized. It has a separate
config switch so that architectures which want to support parallel bringup
can test the split of the CPUHP_BRINGUG step separately.
To enable this the architecture must support the CPU hotplug core sync
mechanism and has to be audited that there are no implicit hotplug state
dependencies which require a fully serialized bringup.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name>
Tested-by: Helge Deller <deller@gmx.de> # parisc
Tested-by: Guilherme G. Piccoli <gpiccoli@igalia.com> # Steam Deck
Link: https://lore.kernel.org/r/20230512205257.080801387@linutronix.de
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David Woodhouse
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6d712b9b3a |
cpu/hotplug: Reset task stack state in _cpu_up()
Commit
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Thomas Gleixner
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6f0621238b |
cpu/hotplug: Add CPU state tracking and synchronization
The CPU state tracking and synchronization mechanism in smpboot.c is
completely independent of the hotplug code and all logic around it is
implemented in architecture specific code.
Except for the state reporting of the AP there is absolutely nothing
architecture specific and the sychronization and decision functions can be
moved into the generic hotplug core code.
Provide an integrated variant and add the core synchronization and decision
points. This comes in two flavours:
1) DEAD state synchronization
Updated by the architecture code once the AP reaches the point where
it is ready to be torn down by the control CPU, e.g. by removing power
or clocks or tear down via the hypervisor.
The control CPU waits for this state to be reached with a timeout. If
the state is reached an architecture specific cleanup function is
invoked.
2) Full state synchronization
This extends #1 with AP alive synchronization. This is new
functionality, which allows to replace architecture specific wait
mechanims, e.g. cpumasks, completely.
It also prevents that an AP which is in a limbo state can be brought
up again. This can happen when an AP failed to report dead state
during a previous off-line operation.
The dead synchronization is what most architectures use. Only x86 makes a
bringup decision based on that state at the moment.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name>
Tested-by: Helge Deller <deller@gmx.de> # parisc
Tested-by: Guilherme G. Piccoli <gpiccoli@igalia.com> # Steam Deck
Link: https://lore.kernel.org/r/20230512205256.476305035@linutronix.de
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Thomas Gleixner
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22b612e2d5 |
cpu/hotplug: Rework sparse_irq locking in bringup_cpu()
There is no harm to hold sparse_irq lock until the upcoming CPU completes in cpuhp_online_idle(). This allows to remove cpu_online() synchronization from architecture code. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Tested-by: Michael Kelley <mikelley@microsoft.com> Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name> Tested-by: Helge Deller <deller@gmx.de> # parisc Tested-by: Guilherme G. Piccoli <gpiccoli@igalia.com> # Steam Deck Link: https://lore.kernel.org/r/20230512205256.263722880@linutronix.de |
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Thomas Gleixner
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ba831b7b1a |
cpu/hotplug: Mark arch_disable_smp_support() and bringup_nonboot_cpus() __init
No point in keeping them around. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Tested-by: Michael Kelley <mikelley@microsoft.com> Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name> Tested-by: Helge Deller <deller@gmx.de> # parisc Tested-by: Guilherme G. Piccoli <gpiccoli@igalia.com> # Steam Deck Link: https://lore.kernel.org/r/20230512205255.551974164@linutronix.de |
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Linus Torvalds
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7fa8a8ee94 |
- Nick Piggin's "shoot lazy tlbs" series, to improve the peformance of
switching from a user process to a kernel thread.
- More folio conversions from Kefeng Wang, Zhang Peng and Pankaj Raghav.
- zsmalloc performance improvements from Sergey Senozhatsky.
- Yue Zhao has found and fixed some data race issues around the
alteration of memcg userspace tunables.
- VFS rationalizations from Christoph Hellwig:
- removal of most of the callers of write_one_page().
- make __filemap_get_folio()'s return value more useful
- Luis Chamberlain has changed tmpfs so it no longer requires swap
backing. Use `mount -o noswap'.
- Qi Zheng has made the slab shrinkers operate locklessly, providing
some scalability benefits.
- Keith Busch has improved dmapool's performance, making part of its
operations O(1) rather than O(n).
- Peter Xu adds the UFFD_FEATURE_WP_UNPOPULATED feature to userfaultd,
permitting userspace to wr-protect anon memory unpopulated ptes.
- Kirill Shutemov has changed MAX_ORDER's meaning to be inclusive rather
than exclusive, and has fixed a bunch of errors which were caused by its
unintuitive meaning.
- Axel Rasmussen give userfaultfd the UFFDIO_CONTINUE_MODE_WP feature,
which causes minor faults to install a write-protected pte.
- Vlastimil Babka has done some maintenance work on vma_merge():
cleanups to the kernel code and improvements to our userspace test
harness.
- Cleanups to do_fault_around() by Lorenzo Stoakes.
- Mike Rapoport has moved a lot of initialization code out of various
mm/ files and into mm/mm_init.c.
- Lorenzo Stoakes removd vmf_insert_mixed_prot(), which was added for
DRM, but DRM doesn't use it any more.
- Lorenzo has also coverted read_kcore() and vread() to use iterators
and has thereby removed the use of bounce buffers in some cases.
- Lorenzo has also contributed further cleanups of vma_merge().
- Chaitanya Prakash provides some fixes to the mmap selftesting code.
- Matthew Wilcox changes xfs and afs so they no longer take sleeping
locks in ->map_page(), a step towards RCUification of pagefaults.
- Suren Baghdasaryan has improved mmap_lock scalability by switching to
per-VMA locking.
- Frederic Weisbecker has reworked the percpu cache draining so that it
no longer causes latency glitches on cpu isolated workloads.
- Mike Rapoport cleans up and corrects the ARCH_FORCE_MAX_ORDER Kconfig
logic.
- Liu Shixin has changed zswap's initialization so we no longer waste a
chunk of memory if zswap is not being used.
- Yosry Ahmed has improved the performance of memcg statistics flushing.
- David Stevens has fixed several issues involving khugepaged,
userfaultfd and shmem.
- Christoph Hellwig has provided some cleanup work to zram's IO-related
code paths.
- David Hildenbrand has fixed up some issues in the selftest code's
testing of our pte state changing.
- Pankaj Raghav has made page_endio() unneeded and has removed it.
- Peter Xu contributed some rationalizations of the userfaultfd
selftests.
- Yosry Ahmed has fixed an issue around memcg's page recalim accounting.
- Chaitanya Prakash has fixed some arm-related issues in the
selftests/mm code.
- Longlong Xia has improved the way in which KSM handles hwpoisoned
pages.
- Peter Xu fixes a few issues with uffd-wp at fork() time.
- Stefan Roesch has changed KSM so that it may now be used on a
per-process and per-cgroup basis.
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Merge tag 'mm-stable-2023-04-27-15-30' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull MM updates from Andrew Morton:
- Nick Piggin's "shoot lazy tlbs" series, to improve the peformance of
switching from a user process to a kernel thread.
- More folio conversions from Kefeng Wang, Zhang Peng and Pankaj
Raghav.
- zsmalloc performance improvements from Sergey Senozhatsky.
- Yue Zhao has found and fixed some data race issues around the
alteration of memcg userspace tunables.
- VFS rationalizations from Christoph Hellwig:
- removal of most of the callers of write_one_page()
- make __filemap_get_folio()'s return value more useful
- Luis Chamberlain has changed tmpfs so it no longer requires swap
backing. Use `mount -o noswap'.
- Qi Zheng has made the slab shrinkers operate locklessly, providing
some scalability benefits.
- Keith Busch has improved dmapool's performance, making part of its
operations O(1) rather than O(n).
- Peter Xu adds the UFFD_FEATURE_WP_UNPOPULATED feature to userfaultd,
permitting userspace to wr-protect anon memory unpopulated ptes.
- Kirill Shutemov has changed MAX_ORDER's meaning to be inclusive
rather than exclusive, and has fixed a bunch of errors which were
caused by its unintuitive meaning.
- Axel Rasmussen give userfaultfd the UFFDIO_CONTINUE_MODE_WP feature,
which causes minor faults to install a write-protected pte.
- Vlastimil Babka has done some maintenance work on vma_merge():
cleanups to the kernel code and improvements to our userspace test
harness.
- Cleanups to do_fault_around() by Lorenzo Stoakes.
- Mike Rapoport has moved a lot of initialization code out of various
mm/ files and into mm/mm_init.c.
- Lorenzo Stoakes removd vmf_insert_mixed_prot(), which was added for
DRM, but DRM doesn't use it any more.
- Lorenzo has also coverted read_kcore() and vread() to use iterators
and has thereby removed the use of bounce buffers in some cases.
- Lorenzo has also contributed further cleanups of vma_merge().
- Chaitanya Prakash provides some fixes to the mmap selftesting code.
- Matthew Wilcox changes xfs and afs so they no longer take sleeping
locks in ->map_page(), a step towards RCUification of pagefaults.
- Suren Baghdasaryan has improved mmap_lock scalability by switching to
per-VMA locking.
- Frederic Weisbecker has reworked the percpu cache draining so that it
no longer causes latency glitches on cpu isolated workloads.
- Mike Rapoport cleans up and corrects the ARCH_FORCE_MAX_ORDER Kconfig
logic.
- Liu Shixin has changed zswap's initialization so we no longer waste a
chunk of memory if zswap is not being used.
- Yosry Ahmed has improved the performance of memcg statistics
flushing.
- David Stevens has fixed several issues involving khugepaged,
userfaultfd and shmem.
- Christoph Hellwig has provided some cleanup work to zram's IO-related
code paths.
- David Hildenbrand has fixed up some issues in the selftest code's
testing of our pte state changing.
- Pankaj Raghav has made page_endio() unneeded and has removed it.
- Peter Xu contributed some rationalizations of the userfaultfd
selftests.
- Yosry Ahmed has fixed an issue around memcg's page recalim
accounting.
- Chaitanya Prakash has fixed some arm-related issues in the
selftests/mm code.
- Longlong Xia has improved the way in which KSM handles hwpoisoned
pages.
- Peter Xu fixes a few issues with uffd-wp at fork() time.
- Stefan Roesch has changed KSM so that it may now be used on a
per-process and per-cgroup basis.
* tag 'mm-stable-2023-04-27-15-30' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (369 commits)
mm,unmap: avoid flushing TLB in batch if PTE is inaccessible
shmem: restrict noswap option to initial user namespace
mm/khugepaged: fix conflicting mods to collapse_file()
sparse: remove unnecessary 0 values from rc
mm: move 'mmap_min_addr' logic from callers into vm_unmapped_area()
hugetlb: pte_alloc_huge() to replace huge pte_alloc_map()
maple_tree: fix allocation in mas_sparse_area()
mm: do not increment pgfault stats when page fault handler retries
zsmalloc: allow only one active pool compaction context
selftests/mm: add new selftests for KSM
mm: add new KSM process and sysfs knobs
mm: add new api to enable ksm per process
mm: shrinkers: fix debugfs file permissions
mm: don't check VMA write permissions if the PTE/PMD indicates write permissions
migrate_pages_batch: fix statistics for longterm pin retry
userfaultfd: use helper function range_in_vma()
lib/show_mem.c: use for_each_populated_zone() simplify code
mm: correct arg in reclaim_pages()/reclaim_clean_pages_from_list()
fs/buffer: convert create_page_buffers to folio_create_buffers
fs/buffer: add folio_create_empty_buffers helper
...
|
||
Nicholas Piggin
|
aa464ba9a1 |
lazy tlb: introduce lazy tlb mm refcount helper functions
Add explicit _lazy_tlb annotated functions for lazy tlb mm refcounting. This makes the lazy tlb mm references more obvious, and allows the refcounting scheme to be modified in later changes. There is no functional change with this patch. Link: https://lkml.kernel.org/r/20230203071837.1136453-3-npiggin@gmail.com Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Nadav Amit <nadav.amit@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@redhat.com> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
Greg Kroah-Hartman
|
db281d59e2 |
cpu/hotplug: move to use bus_get_dev_root()
Direct access to the struct bus_type dev_root pointer is going away soon so replace that with a call to bus_get_dev_root() instead, which is what it is there for. Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Valentin Schneider <vschneid@redhat.com> Cc: Phil Auld <pauld@redhat.com> Cc: Steven Price <steven.price@arm.com> Cc: Juri Lelli <juri.lelli@redhat.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Vincent Donnefort <vdonnefort@google.com> Cc: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com> Cc: "Jason A. Donenfeld" <Jason@zx2c4.com> Link: https://lore.kernel.org/r/20230313182918.1312597-7-gregkh@linuxfoundation.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
||
Vincent Donnefort
|
6f855b39e4 |
cpu/hotplug: Do not bail-out in DYING/STARTING sections
The DYING/STARTING callbacks are not expected to fail. However, as reported by Derek, buggy drivers such as tboot are still free to return errors within those sections, which halts the hot(un)plug and leaves the CPU in an unrecoverable state. As there is no rollback possible, only log the failures and proceed with the following steps. This restores the hotplug behaviour prior to commit |
||
Phil Auld
|
d385febc9a |
cpu/hotplug: Set cpuhp target for boot cpu
Since the boot cpu does not go through the hotplug process it ends up with state == CPUHP_ONLINE but target == CPUHP_OFFLINE. So set the target to match in boot_cpu_hotplug_init(). Signed-off-by: Phil Auld <pauld@redhat.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Valentin Schneider <vschneid@redhat.com> Link: https://lore.kernel.org/r/20221117162329.3164999-3-pauld@redhat.com |
||
|
Phil Auld
|
64ea6e44f8 |
cpu/hotplug: Make target_store() a nop when target == state
Writing the current state back in hotplug/target calls cpu_down()
which will set cpu dying even when it isn't and then nothing will
ever clear it. A stress test that reads values and writes them back
for all cpu device files in sysfs will trigger the BUG() in
select_fallback_rq once all cpus are marked as dying.
kernel/cpu.c::target_store()
...
if (st->state < target)
ret = cpu_up(dev->id, target);
else
ret = cpu_down(dev->id, target);
cpu_down() -> cpu_set_state()
bool bringup = st->state < target;
...
if (cpu_dying(cpu) != !bringup)
set_cpu_dying(cpu, !bringup);
Fix this by letting state==target fall through in the target_store()
conditional. Also make sure st->target == target in that case.
Fixes:
|
||
|
Linus Torvalds
|
3a755ebcc2 |
Intel Trust Domain Extensions
This is the Intel version of a confidential computing solution called Trust Domain Extensions (TDX). This series adds support to run the kernel as part of a TDX guest. It provides similar guest protections to AMD's SEV-SNP like guest memory and register state encryption, memory integrity protection and a lot more. Design-wise, it differs from AMD's solution considerably: it uses a software module which runs in a special CPU mode called (Secure Arbitration Mode) SEAM. As the name suggests, this module serves as sort of an arbiter which the confidential guest calls for services it needs during its lifetime. Just like AMD's SNP set, this series reworks and streamlines certain parts of x86 arch code so that this feature can be properly accomodated. -----BEGIN PGP SIGNATURE----- iQIzBAABCgAdFiEEzv7L6UO9uDPlPSfHEsHwGGHeVUoFAmKLbisACgkQEsHwGGHe VUqZLg/7B55iygCwzz0W/KLcXL2cISatUpzGbFs1XTbE9DMz06BPkOsEjF2k8ckv kfZjgqhSx3GvUI80gK0Tn2M2DfIj3nKuNSXd1pfextP7AxEf68FFJsQz1Ju7bHpT pZaG+g8IK4+mnEHEKTCO9ANg/Zw8yqJLdtsCaCNE9SUGUfQ6m/ujTEfsambXDHNm khyCAgpIGSOt51/4apoR9ebyrNCaeVbDawpIPjTy+iyFRc/WyaLFV9CQ8klw4gbw r/90x2JYxvAf0/z/ifT9Wa+TnYiQ0d4VjFbfr0iJ4GcPn5L3EIoIKPE8vPGMpoSX fLSzoNmAOT3ja57ytUUQ3o0edoRUIPEdixOebf9qWvE/aj7W37YRzrlJ8Ej/x9Jy HcI4WZF6Dr1bh6FnI/xX2eVZRzLOL4j9gNyPCwIbvgr1NjDqQnxU7nhxVMmQhJrs IdiEcP5WYerLKfka/uF//QfWUg5mDBgFa1/3xK57Z3j0iKWmgjaPpR0SWlOKjj8G tr0gGN9ejikZTqXKGsHn8fv/R3bjXvbVD8z0IEcx+MIrRmZPnX2QBlg7UA1AXV5n HoVwPFdH1QAtjZq1MRcL4hTOjz3FkS68rg7ZH0f2GWJAzWmEGytBIhECRnN/PFFq VwRB4dCCt0bzqRxkiH5lzdgR+xqRe61juQQsMzg+Flv/trpXDqM= =ac9K -----END PGP SIGNATURE----- Merge tag 'x86_tdx_for_v5.19_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull Intel TDX support from Borislav Petkov: "Intel Trust Domain Extensions (TDX) support. This is the Intel version of a confidential computing solution called Trust Domain Extensions (TDX). This series adds support to run the kernel as part of a TDX guest. It provides similar guest protections to AMD's SEV-SNP like guest memory and register state encryption, memory integrity protection and a lot more. Design-wise, it differs from AMD's solution considerably: it uses a software module which runs in a special CPU mode called (Secure Arbitration Mode) SEAM. As the name suggests, this module serves as sort of an arbiter which the confidential guest calls for services it needs during its lifetime. Just like AMD's SNP set, this series reworks and streamlines certain parts of x86 arch code so that this feature can be properly accomodated" * tag 'x86_tdx_for_v5.19_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (34 commits) x86/tdx: Fix RETs in TDX asm x86/tdx: Annotate a noreturn function x86/mm: Fix spacing within memory encryption features message x86/kaslr: Fix build warning in KASLR code in boot stub Documentation/x86: Document TDX kernel architecture ACPICA: Avoid cache flush inside virtual machines x86/tdx/ioapic: Add shared bit for IOAPIC base address x86/mm: Make DMA memory shared for TD guest x86/mm/cpa: Add support for TDX shared memory x86/tdx: Make pages shared in ioremap() x86/topology: Disable CPU online/offline control for TDX guests x86/boot: Avoid #VE during boot for TDX platforms x86/boot: Set CR0.NE early and keep it set during the boot x86/acpi/x86/boot: Add multiprocessor wake-up support x86/boot: Add a trampoline for booting APs via firmware handoff x86/tdx: Wire up KVM hypercalls x86/tdx: Port I/O: Add early boot support x86/tdx: Port I/O: Add runtime hypercalls x86/boot: Port I/O: Add decompression-time support for TDX x86/boot: Port I/O: Allow to hook up alternative helpers ... |
||
Steven Price
|
d308077e5e |
cpu/hotplug: Initialise all cpuhp_cpu_state structs earlier
Rather than waiting until a CPU is first brought online, do the initialisation of the cpuhp_cpu_state structure for each CPU during the __init phase. This saves a (small) amount of non-__init memory and avoids potential confusion about when the cpuhp_cpu_state struct is valid. Suggested-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Steven Price <steven.price@arm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20220411152233.474129-3-steven.price@arm.com |
||
|
Steven Price
|
b7ba6d8dc3 |
cpu/hotplug: Remove the 'cpu' member of cpuhp_cpu_state
Currently the setting of the 'cpu' member of struct cpuhp_cpu_state in
cpuhp_create() is too late as it is used earlier in _cpu_up().
If kzalloc_node() in __smpboot_create_thread() fails then the rollback will
be done with st->cpu==0 causing CPU0 to be erroneously set to be dying,
causing the scheduler to get mightily confused and throw its toys out of
the pram.
However the cpu number is actually available directly, so simply remove
the 'cpu' member and avoid the problem in the first place.
Fixes:
|
||
Kuppuswamy Sathyanarayanan
|
bae1a962ac |
x86/topology: Disable CPU online/offline control for TDX guests
Unlike regular VMs, TDX guests use the firmware hand-off wakeup method to wake up the APs during the boot process. This wakeup model uses a mailbox to communicate with firmware to bring up the APs. As per the design, this mailbox can only be used once for the given AP, which means after the APs are booted, the same mailbox cannot be used to offline/online the given AP. More details about this requirement can be found in Intel TDX Virtual Firmware Design Guide, sec titled "AP initialization in OS" and in sec titled "Hotplug Device". Since the architecture does not support any method of offlining the CPUs, disable CPU hotplug support in the kernel. Since this hotplug disable feature can be re-used by other VM guests, add a new CC attribute CC_ATTR_HOTPLUG_DISABLED and use it to disable the hotplug support. Attempt to offline CPU will fail with -EOPNOTSUPP. Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Reviewed-by: Andi Kleen <ak@linux.intel.com> Reviewed-by: Tony Luck <tony.luck@intel.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lkml.kernel.org/r/20220405232939.73860-25-kirill.shutemov@linux.intel.com |
||
|
Linus Torvalds
|
3fe2f7446f |
Changes in this cycle were:
- Cleanups for SCHED_DEADLINE
- Tracing updates/fixes
- CPU Accounting fixes
- First wave of changes to optimize the overhead of the scheduler build,
from the fast-headers tree - including placeholder *_api.h headers for
later header split-ups.
- Preempt-dynamic using static_branch() for ARM64
- Isolation housekeeping mask rework; preperatory for further changes
- NUMA-balancing: deal with CPU-less nodes
- NUMA-balancing: tune systems that have multiple LLC cache domains per node (eg. AMD)
- Updates to RSEQ UAPI in preparation for glibc usage
- Lots of RSEQ/selftests, for same
- Add Suren as PSI co-maintainer
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'sched-core-2022-03-22' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler updates from Ingo Molnar:
- Cleanups for SCHED_DEADLINE
- Tracing updates/fixes
- CPU Accounting fixes
- First wave of changes to optimize the overhead of the scheduler
build, from the fast-headers tree - including placeholder *_api.h
headers for later header split-ups.
- Preempt-dynamic using static_branch() for ARM64
- Isolation housekeeping mask rework; preperatory for further changes
- NUMA-balancing: deal with CPU-less nodes
- NUMA-balancing: tune systems that have multiple LLC cache domains per
node (eg. AMD)
- Updates to RSEQ UAPI in preparation for glibc usage
- Lots of RSEQ/selftests, for same
- Add Suren as PSI co-maintainer
* tag 'sched-core-2022-03-22' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (81 commits)
sched/headers: ARM needs asm/paravirt_api_clock.h too
sched/numa: Fix boot crash on arm64 systems
headers/prep: Fix header to build standalone: <linux/psi.h>
sched/headers: Only include <linux/entry-common.h> when CONFIG_GENERIC_ENTRY=y
cgroup: Fix suspicious rcu_dereference_check() usage warning
sched/preempt: Tell about PREEMPT_DYNAMIC on kernel headers
sched/topology: Remove redundant variable and fix incorrect type in build_sched_domains
sched/deadline,rt: Remove unused parameter from pick_next_[rt|dl]_entity()
sched/deadline,rt: Remove unused functions for !CONFIG_SMP
sched/deadline: Use __node_2_[pdl|dle]() and rb_first_cached() consistently
sched/deadline: Merge dl_task_can_attach() and dl_cpu_busy()
sched/deadline: Move bandwidth mgmt and reclaim functions into sched class source file
sched/deadline: Remove unused def_dl_bandwidth
sched/tracing: Report TASK_RTLOCK_WAIT tasks as TASK_UNINTERRUPTIBLE
sched/tracing: Don't re-read p->state when emitting sched_switch event
sched/rt: Plug rt_mutex_setprio() vs push_rt_task() race
sched/cpuacct: Remove redundant RCU read lock
sched/cpuacct: Optimize away RCU read lock
sched/cpuacct: Fix charge percpu cpuusage
sched/headers: Reorganize, clean up and optimize kernel/sched/sched.h dependencies
...
|
||
Jason A. Donenfeld
|
3191dd5a11 |
random: clear fast pool, crng, and batches in cpuhp bring up
For the irq randomness fast pool, rather than having to use expensive atomics, which were visibly the most expensive thing in the entire irq handler, simply take care of the extreme edge case of resetting count to zero in the cpuhp online handler, just after workqueues have been reenabled. This simplifies the code a bit and lets us use vanilla variables rather than atomics, and performance should be improved. As well, very early on when the CPU comes up, while interrupts are still disabled, we clear out the per-cpu crng and its batches, so that it always starts with fresh randomness. Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Theodore Ts'o <tytso@mit.edu> Cc: Sultan Alsawaf <sultan@kerneltoast.com> Cc: Dominik Brodowski <linux@dominikbrodowski.net> Acked-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com> |
||
|
Frederic Weisbecker
|
04d4e665a6 |
sched/isolation: Use single feature type while referring to housekeeping cpumask
Refer to housekeeping APIs using single feature types instead of flags. This prevents from passing multiple isolation features at once to housekeeping interfaces, which soon won't be possible anymore as each isolation features will have their own cpumask. Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Juri Lelli <juri.lelli@redhat.com> Reviewed-by: Phil Auld <pauld@redhat.com> Link: https://lore.kernel.org/r/20220207155910.527133-5-frederic@kernel.org |
||
Mark Rutland
|
dce1ca0525 |
sched/scs: Reset task stack state in bringup_cpu()
To hot unplug a CPU, the idle task on that CPU calls a few layers of C code before finally leaving the kernel. When KASAN is in use, poisoned shadow is left around for each of the active stack frames, and when shadow call stacks are in use. When shadow call stacks (SCS) are in use the task's saved SCS SP is left pointing at an arbitrary point within the task's shadow call stack. When a CPU is offlined than onlined back into the kernel, this stale state can adversely affect execution. Stale KASAN shadow can alias new stackframes and result in bogus KASAN warnings. A stale SCS SP is effectively a memory leak, and prevents a portion of the shadow call stack being used. Across a number of hotplug cycles the idle task's entire shadow call stack can become unusable. We previously fixed the KASAN issue in commit: |
||
Dongli Zhang
|
ebca71a8c9 |
cpu/hotplug: Add debug printks for hotplug callback failures
CPU hotplug callbacks can fail and cause a rollback to the previous state. These failures are silent and therefore hard to debug. Add pr_debug() to the up and down paths which provide information about the error code, the CPU and the failed state. The debug printks can be enabled via kernel command line or sysfs. [ tglx: Adopt to current mainline, massage printk and changelog ] Signed-off-by: Dongli Zhang <dongli.zhang@oracle.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Qais Yousef <qais.yousef@arm.com> Link: https://lore.kernel.org/r/20210409055316.1709-1-dongli.zhang@oracle.com |
||
YueHaibing
|
1782dc87b2 |
cpu/hotplug: Use DEVICE_ATTR_*() macro
Use DEVICE_ATTR_*() helper instead of plain DEVICE_ATTR, which makes the code a bit shorter and easier to read. Signed-off-by: YueHaibing <yuehaibing@huawei.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20210527141105.2312-1-yuehaibing@huawei.com |
||
Randy Dunlap
|
11bc021d1f |
cpu/hotplug: Eliminate all kernel-doc warnings
kernel/cpu.c:57: warning: cannot understand function prototype: 'struct cpuhp_cpu_state ' kernel/cpu.c:115: warning: cannot understand function prototype: 'struct cpuhp_step ' kernel/cpu.c:146: warning: This comment starts with '/**', but isn't a kernel-doc comment. Refer Documentation/doc-guide/kernel-doc.rst * cpuhp_invoke_callback _ Invoke the callbacks for a given state kernel/cpu.c:75: warning: Function parameter or member 'fail' not described in 'cpuhp_cpu_state' kernel/cpu.c:75: warning: Function parameter or member 'cpu' not described in 'cpuhp_cpu_state' kernel/cpu.c:75: warning: Function parameter or member 'node' not described in 'cpuhp_cpu_state' kernel/cpu.c:75: warning: Function parameter or member 'last' not described in 'cpuhp_cpu_state' kernel/cpu.c:130: warning: Function parameter or member 'list' not described in 'cpuhp_step' kernel/cpu.c:130: warning: Function parameter or member 'multi_instance' not described in 'cpuhp_step' kernel/cpu.c:158: warning: No description found for return value of 'cpuhp_invoke_callback' kernel/cpu.c:1188: warning: No description found for return value of 'cpu_device_down' kernel/cpu.c:1400: warning: No description found for return value of 'cpu_device_up' kernel/cpu.c:1425: warning: No description found for return value of 'bringup_hibernate_cpu' Signed-off-by: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20210809223825.24512-1-rdunlap@infradead.org |
||
Baokun Li
|
ed3cd1da67 |
cpu/hotplug: Fix kernel doc warnings for __cpuhp_setup_state_cpuslocked()
Fixes the following W=1 kernel build warning(s): kernel/cpu.c:1949: warning: Function parameter or member 'name' not described in '__cpuhp_setup_state_cpuslocked' Signed-off-by: Baokun Li <libaokun1@huawei.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20210605063003.681049-1-libaokun1@huawei.com |
||
|
Linus Torvalds
|
62180152e0 |
A fix for the CPU hotplug and cpusets interaction:
cpusets delegate the hotplug work to a workqueue to prevent a lock order inversion vs. the CPU hotplug lock. The work is not flushed before the hotplug operation returns which creates user visible inconsistent state. Prevent this by flushing the work after dropping CPU hotplug lock and before releasing the outer mutex which serializes the CPU hotplug related sysfs interface operations. -----BEGIN PGP SIGNATURE----- iQJHBAABCgAxFiEEQp8+kY+LLUocC4bMphj1TA10mKEFAmDbJLATHHRnbHhAbGlu dXRyb25peC5kZQAKCRCmGPVMDXSYoaHxD/9yQI2tNgGcjdQBtg8z9Vvs/j7kG5A0 l8R9zAWSqocXcWMsV8nqjiFcNatHIfuR5Q6vyysDftH2mqKRr5MHa3/m+Ow/VPGu nqBDAla9M9wQIp8f2yjHHCBB5TjUDUD9htRkhgriCRr31pvhZHTAQKcOS+atLfxG 4FB0/n2hfcJJZtgWWlie4JAWBo8xQn5yOicH/OBs2bEnJSGoaSJrKmCiRCeBUjAr fYUCMYKxqWfwwJzWQPefG/eVnSaE6fSHAgRFvFFdOOvaSwyFIly9LpP8H5MPOE/p 0rsMQAOwnr9dA+amPp3RNS3ZEMvE/FHamHVcjXaXa76HiunCw+SH866O9z+Ta3gm P/SvqxusJAVhvyKQk6FsC/hYv9QX1xPsNVQRZ7oZb4ftBj/n964TO6kiCEzuSX0c MJBeAfDbz20hDQol+NO8/JeKJXU2utLXQ+oyjzIkHtCka9PFt0fGlgfUzh3VtbOC h/vlhtrr2DsWy9NbalkzjeyaIoetbQPsANs0iGBBFZ3hNyNmYlxB5ujTcUP+//vm NEOBMmYOsxe3FnWPKnRnJmEEMJn23JuxoswZhHenSHvOHBs8eJkEhte0EK5lE1Fo /JalFzKBb1WQqKkfDrde3WkevOHrkvBgs84PJDFJcl7uZzsLYCLhPLZC7JNNnrO0 IrWrpFOX9qj1rg== =Lzoh -----END PGP SIGNATURE----- Merge tag 'smp-urgent-2021-06-29' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull CPU hotplug fix from Thomas Gleixner: "A fix for the CPU hotplug and cpusets interaction: cpusets delegate the hotplug work to a workqueue to prevent a lock order inversion vs. the CPU hotplug lock. The work is not flushed before the hotplug operation returns which creates user visible inconsistent state. Prevent this by flushing the work after dropping CPU hotplug lock and before releasing the outer mutex which serializes the CPU hotplug related sysfs interface operations" * tag 'smp-urgent-2021-06-29' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: cpu/hotplug: Cure the cpusets trainwreck |
||
|
Thomas Gleixner
|
b22afcdf04 |
cpu/hotplug: Cure the cpusets trainwreck
Alexey and Joshua tried to solve a cpusets related hotplug problem which is
user space visible and results in unexpected behaviour for some time after
a CPU has been plugged in and the corresponding uevent was delivered.
cpusets delegate the hotplug work (rebuilding cpumasks etc.) to a
workqueue. This is done because the cpusets code has already a lock
nesting of cgroups_mutex -> cpu_hotplug_lock. A synchronous callback or
waiting for the work to finish with cpu_hotplug_lock held can and will
deadlock because that results in the reverse lock order.
As a consequence the uevent can be delivered before cpusets have consistent
state which means that a user space invocation of sched_setaffinity() to
move a task to the plugged CPU fails up to the point where the scheduled
work has been processed.
The same is true for CPU unplug, but that does not create user observable
failure (yet).
It's still inconsistent to claim that an operation is finished before it
actually is and that's the real issue at hand. uevents just make it
reliably observable.
Obviously the problem should be fixed in cpusets/cgroups, but untangling
that is pretty much impossible because according to the changelog of the
commit which introduced this 8 years ago:
3a5a6d0c2b03("cpuset: don't nest cgroup_mutex inside get_online_cpus()")
the lock order cgroups_mutex -> cpu_hotplug_lock is a design decision and
the whole code is built around that.
So bite the bullet and invoke the relevant cpuset function, which waits for
the work to finish, in _cpu_up/down() after dropping cpu_hotplug_lock and
only when tasks are not frozen by suspend/hibernate because that would
obviously wait forever.
Waiting there with cpu_add_remove_lock, which is protecting the present
and possible CPU maps, held is not a problem at all because neither work
queues nor cpusets/cgroups have any lockchains related to that lock.
Waiting in the hotplug machinery is not problematic either because there
are already state callbacks which wait for hardware queues to drain. It
makes the operations slightly slower, but hotplug is slow anyway.
This ensures that state is consistent before returning from a hotplug
up/down operation. It's still inconsistent during the operation, but that's
a different story.
Add a large comment which explains why this is done and why this is not a
dump ground for the hack of the day to work around half thought out locking
schemes. Document also the implications vs. hotplug operations and
serialization or the lack of it.
Thanks to Alexy and Joshua for analyzing why this temporary
sched_setaffinity() failure happened.
Fixes: 3a5a6d0c2b03("cpuset: don't nest cgroup_mutex inside get_online_cpus()")
Reported-by: Alexey Klimov <aklimov@redhat.com>
Reported-by: Joshua Baker <jobaker@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Alexey Klimov <aklimov@redhat.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/87tuowcnv3.ffs@nanos.tec.linutronix.de
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Yuan ZhaoXiong
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130708331b |
cpu/hotplug: Simplify access to percpu cpuhp_state
It is unnecessary to invoke per_cpu_ptr() everytime to access cpuhp_state. Use the available pointer instead. Signed-off-by: Yuan ZhaoXiong <yuanzhaoxiong@baidu.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Valentin Schneider <valentin.schneider@arm.com> Link: https://lore.kernel.org/r/1621776690-13264-1-git-send-email-yuanzhaoxiong@baidu.com |