Commit graph

106 commits

Author SHA1 Message Date
Borislav Petkov (AMD)
d8010d4ba4 x86/bugs: Add a Transient Scheduler Attacks mitigation
Add the required features detection glue to bugs.c et all in order to
support the TSA mitigation.

Co-developed-by: Kim Phillips <kim.phillips@amd.com>
Signed-off-by: Kim Phillips <kim.phillips@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
2025-06-17 17:17:02 +02:00
Linus Torvalds
47cf96fbe3 arm64 updates for 6.16
ACPI, EFI and PSCI:
  - Decouple Arm's "Software Delegated Exception Interface" (SDEI)
    support from the ACPI GHES code so that it can be used by platforms
    booted with device-tree.
 
  - Remove unnecessary per-CPU tracking of the FPSIMD state across EFI
    runtime calls.
 
  - Fix a node refcount imbalance in the PSCI device-tree code.
 
 CPU Features:
  - Ensure register sanitisation is applied to fields in ID_AA64MMFR4.
 
  - Expose AIDR_EL1 to userspace via sysfs, primarily so that KVM guests
    can reliably query the underlying CPU types from the VMM.
 
  - Re-enabling of SME support (CONFIG_ARM64_SME) as a result of fixes
    to our context-switching, signal handling and ptrace code.
 
 Entry code:
  - Hook up TIF_NEED_RESCHED_LAZY so that CONFIG_PREEMPT_LAZY can be
    selected.
 
 Memory management:
  - Prevent BSS exports from being used by the early PI code.
 
  - Propagate level and stride information to the low-level TLB
    invalidation routines when operating on hugetlb entries.
 
  - Use the page-table contiguous hint for vmap() mappings with
    VM_ALLOW_HUGE_VMAP where possible.
 
  - Optimise vmalloc()/vmap() page-table updates to use "lazy MMU mode"
    and hook this up on arm64 so that the trailing DSB (used to publish
    the updates to the hardware walker) can be deferred until the end of
    the mapping operation.
 
  - Extend mmap() randomisation for 52-bit virtual addresses (on par with
    48-bit addressing) and remove limited support for randomisation of
    the linear map.
 
 Perf and PMUs:
  - Add support for probing the CMN-S3 driver using ACPI.
 
  - Minor driver fixes to the CMN, Arm-NI and amlogic PMU drivers.
 
 Selftests:
  - Fix FPSIMD and SME tests to align with the freshly re-enabled SME
    support.
 
  - Fix default setting of the OUTPUT variable so that tests are
    installed in the right location.
 
 vDSO:
  - Replace raw counter access from inline assembly code with a call to
    the the __arch_counter_get_cntvct() helper function.
 
 Miscellaneous:
  - Add some missing header inclusions to the CCA headers.
 
  - Rework rendering of /proc/cpuinfo to follow the x86-approach and
    avoid repeated buffer expansion (the user-visible format remains
    identical).
 
  - Remove redundant selection of CONFIG_CRC32
 
  - Extend early error message when failing to map the device-tree blob.
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Merge tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux

Pull arm64 updates from Will Deacon:
 "The headline feature is the re-enablement of support for Arm's
  Scalable Matrix Extension (SME) thanks to a bumper crop of fixes
  from Mark Rutland.

  If matrices aren't your thing, then Ryan's page-table optimisation
  work is much more interesting.

  Summary:

  ACPI, EFI and PSCI:

   - Decouple Arm's "Software Delegated Exception Interface" (SDEI)
     support from the ACPI GHES code so that it can be used by platforms
     booted with device-tree

   - Remove unnecessary per-CPU tracking of the FPSIMD state across EFI
     runtime calls

   - Fix a node refcount imbalance in the PSCI device-tree code

  CPU Features:

   - Ensure register sanitisation is applied to fields in ID_AA64MMFR4

   - Expose AIDR_EL1 to userspace via sysfs, primarily so that KVM
     guests can reliably query the underlying CPU types from the VMM

   - Re-enabling of SME support (CONFIG_ARM64_SME) as a result of fixes
     to our context-switching, signal handling and ptrace code

  Entry code:

   - Hook up TIF_NEED_RESCHED_LAZY so that CONFIG_PREEMPT_LAZY can be
     selected

  Memory management:

   - Prevent BSS exports from being used by the early PI code

   - Propagate level and stride information to the low-level TLB
     invalidation routines when operating on hugetlb entries

   - Use the page-table contiguous hint for vmap() mappings with
     VM_ALLOW_HUGE_VMAP where possible

   - Optimise vmalloc()/vmap() page-table updates to use "lazy MMU mode"
     and hook this up on arm64 so that the trailing DSB (used to publish
     the updates to the hardware walker) can be deferred until the end
     of the mapping operation

   - Extend mmap() randomisation for 52-bit virtual addresses (on par
     with 48-bit addressing) and remove limited support for
     randomisation of the linear map

  Perf and PMUs:

   - Add support for probing the CMN-S3 driver using ACPI

   - Minor driver fixes to the CMN, Arm-NI and amlogic PMU drivers

  Selftests:

   - Fix FPSIMD and SME tests to align with the freshly re-enabled SME
     support

   - Fix default setting of the OUTPUT variable so that tests are
     installed in the right location

  vDSO:

   - Replace raw counter access from inline assembly code with a call to
     the the __arch_counter_get_cntvct() helper function

  Miscellaneous:

   - Add some missing header inclusions to the CCA headers

   - Rework rendering of /proc/cpuinfo to follow the x86-approach and
     avoid repeated buffer expansion (the user-visible format remains
     identical)

   - Remove redundant selection of CONFIG_CRC32

   - Extend early error message when failing to map the device-tree
     blob"

* tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (83 commits)
  arm64: cputype: Add cputype definition for HIP12
  arm64: el2_setup.h: Make __init_el2_fgt labels consistent, again
  perf/arm-cmn: Add CMN S3 ACPI binding
  arm64/boot: Disallow BSS exports to startup code
  arm64/boot: Move global CPU override variables out of BSS
  arm64/boot: Move init_pgdir[] and init_idmap_pgdir[] into __pi_ namespace
  perf/arm-cmn: Initialise cmn->cpu earlier
  kselftest/arm64: Set default OUTPUT path when undefined
  arm64: Update comment regarding values in __boot_cpu_mode
  arm64: mm: Drop redundant check in pmd_trans_huge()
  arm64/mm: Re-organise setting up FEAT_S1PIE registers PIRE0_EL1 and PIR_EL1
  arm64/mm: Permit lazy_mmu_mode to be nested
  arm64/mm: Disable barrier batching in interrupt contexts
  arm64/cpuinfo: only show one cpu's info in c_show()
  arm64/mm: Batch barriers when updating kernel mappings
  mm/vmalloc: Enter lazy mmu mode while manipulating vmalloc ptes
  arm64/mm: Support huge pte-mapped pages in vmap
  mm/vmalloc: Gracefully unmap huge ptes
  mm/vmalloc: Warn on improper use of vunmap_range()
  arm64/mm: Hoist barriers out of set_ptes_anysz() loop
  ...
2025-05-28 14:55:35 -07:00
Linus Torvalds
c89756bcf4 Power management updates for 6.16-rc1
- Fix potential division-by-zero error in em_compute_costs() (Yaxiong
    Tian).
 
  - Fix typos in energy model documentation and example driver code (Moon
    Hee Lee, Atul Kumar Pant).
 
  - Rearrange the energy model management code and add a new function for
    adjusting a CPU energy model after adjusting the capacity of the
    given CPU to it (Rafael Wysocki).
 
  - Refactor cpufreq_online(), add and use cpufreq policy locking guards,
    use __free() in policy reference counting, and clean up core cpufreq
    code on top of that (Rafael Wysocki).
 
  - Fix boost handling on CPU suspend/resume and sysfs updates (Viresh
    Kumar).
 
  - Fix des_perf clamping with max_perf in amd_pstate_update() (Dhananjay
    Ugwekar).
 
  - Add offline, online and suspend callbacks to the amd-pstate driver,
    rename and use the existing amd_pstate_epp callbacks in it (Dhananjay
    Ugwekar).
 
  - Add support for the "Requested CPU Min frequency" BIOS option to the
    amd-pstate driver (Dhananjay Ugwekar).
 
  - Reset amd-pstate driver mode after running selftests (Swapnil
    Sapkal).
 
  - Avoid shadowing ret in amd_pstate_ut_check_driver() (Nathan
    Chancellor).
 
  - Add helper for governor checks to the schedutil cpufreq governor and
    move cpufreq-specific EAS checks to cpufreq (Rafael Wysocki).
 
  - Populate the cpu_capacity sysfs entries from the intel_pstate driver
    after registering asym capacity support (Ricardo Neri).
 
  - Add support for enabling Energy-aware scheduling (EAS) to the
    intel_pstate driver when operating in the passive mode on a hybrid
    platform (Rafael Wysocki).
 
  - Drop redundant cpus_read_lock() from store_local_boost() in the
    cpufreq core (Seyediman Seyedarab).
 
  - Replace sscanf() with kstrtouint() in the cpufreq code and use a
    symbol instead of a raw number in it (Bowen Yu).
 
  - Add support for autonomous CPU performance state selection to the
    CPPC cpufreq driver (Lifeng Zheng).
 
  - OPP: Add dev_pm_opp_set_level() (Praveen Talari).
 
  - Introduce scope-based cleanup headers and mutex locking guards in OPP
    core (Viresh Kumar).
 
  - Switch OPP to use kmemdup_array() (Zhang Enpei).
 
  - Optimize bucket assignment when next_timer_ns equals KTIME_MAX in the
    menu cpuidle governor (Zhongqiu Han).
 
  - Convert the cpuidle PSCI driver to a faux device one (Sudeep Holla).
 
  - Add C1 demotion on/off sysfs knob to the intel_idle driver (Artem
    Bityutskiy).
 
  - Fix typos in two comments in the teo cpuidle governor (Atul Kumar
    Pant).
 
  - Fix denying of auto suspend in pm_suspend_timer_fn() (Charan Teja
    Kalla).
 
  - Move debug runtime PM attributes to runtime_attrs[] (Rafael Wysocki).
 
  - Add new devm_ functions for enabling runtime PM and runtime PM
    reference counting (Bence Csókás).
 
  - Remove size arguments from strscpy() calls in the hibernation core
    code (Thorsten Blum).
 
  - Adjust the handling of devices with asynchronous suspend enabled
    during system suspend and resume to start resuming them immediately
    after resuming their parents and to start suspending such a device
    immediately after suspending its first child (Rafael Wysocki).
 
  - Adjust messages printed during tasks freezing to avoid using
    pr_cont() (Andrew Sayers, Paul Menzel).
 
  - Clean up unnecessary usage of !! in pm_print_times_init() (Zihuan
    Zhang).
 
  - Add missing wakeup source attribute relax_count to sysfs and
    remove the space character at the end ofi the string produced by
    pm_show_wakelocks() (Zijun Hu).
 
  - Add configurable pm_test delay for hibernation (Zihuan Zhang).
 
  - Disable asynchronous suspend in ucsi_ccg_probe() to prevent the
    cypd4226 device on Tegra boards from suspending prematurely (Jon
    Hunter).
 
  - Unbreak printing PM debug messages during hibernation and clean up
    some related code (Rafael Wysocki).
 
  - Add a systemd service to run cpupower and change cpupower binding's
    Makefile to use -lcpupower (John B. Wyatt IV, Francesco Poli).
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Merge tag 'pm-6.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

Pull power management updates from Rafael Wysocki:
 "Once again, the changes are dominated by cpufreq updates, but this
  time the majority of them are cpufreq core changes, mostly related to
  the introduction of policy locking guards and __free() usage, and
  fixes related to boost handling.

  Still, there is also a significant update of the intel_pstate driver
  making it register an energy model when running on a hybrid platform
  which is used for enabling energy-aware scheduling (EAS) if the driver
  operates in the passive mode (and schedutil is used as the cpufreq
  governor for all CPUs which is the passive mode default).

  There are some amd-pstate driver updates too, for a good measure,
  including the "Requested CPU Min frequency" BIOS option support and
  new online/offline callbacks.

  In the cpuidle space, the most significant change is the addition of a
  C1 demotion on/off sysfs knob to intel_idle which should help some
  users to configure their systems more precisely. There is also the
  conversion of the PSCI cpuidle driver to a faux device one and there
  are two small updates of cpuidle governors.

  Device power management is also modified quite a bit, especially the
  handling of devices with asynchronous suspend and resume enabled
  during system transitions. They are now going to be handled more
  asynchronously during suspend transitions and somewhat less
  aggressively during resume transitions.

  Apart from the above, the operating performance points (OPP) library
  is now going to use mutex locking guards and scope-based cleanup
  helpers and there is the usual bunch of assorted fixes and code
  cleanups.

  Specifics:

   - Fix potential division-by-zero error in em_compute_costs() (Yaxiong
     Tian)

   - Fix typos in energy model documentation and example driver code
     (Moon Hee Lee, Atul Kumar Pant)

   - Rearrange the energy model management code and add a new function
     for adjusting a CPU energy model after adjusting the capacity of
     the given CPU to it (Rafael Wysocki)

   - Refactor cpufreq_online(), add and use cpufreq policy locking
     guards, use __free() in policy reference counting, and clean up
     core cpufreq code on top of that (Rafael Wysocki)

   - Fix boost handling on CPU suspend/resume and sysfs updates (Viresh
     Kumar)

   - Fix des_perf clamping with max_perf in amd_pstate_update()
     (Dhananjay Ugwekar)

   - Add offline, online and suspend callbacks to the amd-pstate driver,
     rename and use the existing amd_pstate_epp callbacks in it
     (Dhananjay Ugwekar)

   - Add support for the "Requested CPU Min frequency" BIOS option to
     the amd-pstate driver (Dhananjay Ugwekar)

   - Reset amd-pstate driver mode after running selftests (Swapnil
     Sapkal)

   - Avoid shadowing ret in amd_pstate_ut_check_driver() (Nathan
     Chancellor)

   - Add helper for governor checks to the schedutil cpufreq governor
     and move cpufreq-specific EAS checks to cpufreq (Rafael Wysocki)

   - Populate the cpu_capacity sysfs entries from the intel_pstate
     driver after registering asym capacity support (Ricardo Neri)

   - Add support for enabling Energy-aware scheduling (EAS) to the
     intel_pstate driver when operating in the passive mode on a hybrid
     platform (Rafael Wysocki)

   - Drop redundant cpus_read_lock() from store_local_boost() in the
     cpufreq core (Seyediman Seyedarab)

   - Replace sscanf() with kstrtouint() in the cpufreq code and use a
     symbol instead of a raw number in it (Bowen Yu)

   - Add support for autonomous CPU performance state selection to the
     CPPC cpufreq driver (Lifeng Zheng)

   - OPP: Add dev_pm_opp_set_level() (Praveen Talari)

   - Introduce scope-based cleanup headers and mutex locking guards in
     OPP core (Viresh Kumar)

   - Switch OPP to use kmemdup_array() (Zhang Enpei)

   - Optimize bucket assignment when next_timer_ns equals KTIME_MAX in
     the menu cpuidle governor (Zhongqiu Han)

   - Convert the cpuidle PSCI driver to a faux device one (Sudeep Holla)

   - Add C1 demotion on/off sysfs knob to the intel_idle driver (Artem
     Bityutskiy)

   - Fix typos in two comments in the teo cpuidle governor (Atul Kumar
     Pant)

   - Fix denying of auto suspend in pm_suspend_timer_fn() (Charan Teja
     Kalla)

   - Move debug runtime PM attributes to runtime_attrs[] (Rafael
     Wysocki)

   - Add new devm_ functions for enabling runtime PM and runtime PM
     reference counting (Bence Csókás)

   - Remove size arguments from strscpy() calls in the hibernation core
     code (Thorsten Blum)

   - Adjust the handling of devices with asynchronous suspend enabled
     during system suspend and resume to start resuming them immediately
     after resuming their parents and to start suspending such a device
     immediately after suspending its first child (Rafael Wysocki)

   - Adjust messages printed during tasks freezing to avoid using
     pr_cont() (Andrew Sayers, Paul Menzel)

   - Clean up unnecessary usage of !! in pm_print_times_init() (Zihuan
     Zhang)

   - Add missing wakeup source attribute relax_count to sysfs and remove
     the space character at the end ofi the string produced by
     pm_show_wakelocks() (Zijun Hu)

   - Add configurable pm_test delay for hibernation (Zihuan Zhang)

   - Disable asynchronous suspend in ucsi_ccg_probe() to prevent the
     cypd4226 device on Tegra boards from suspending prematurely (Jon
     Hunter)

   - Unbreak printing PM debug messages during hibernation and clean up
     some related code (Rafael Wysocki)

   - Add a systemd service to run cpupower and change cpupower binding's
     Makefile to use -lcpupower (John B. Wyatt IV, Francesco Poli)"

* tag 'pm-6.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (72 commits)
  cpufreq: CPPC: Add support for autonomous selection
  cpufreq: Update sscanf() to kstrtouint()
  cpufreq: Replace magic number
  OPP: switch to use kmemdup_array()
  PM: freezer: Rewrite restarting tasks log to remove stray *done.*
  PM: runtime: fix denying of auto suspend in pm_suspend_timer_fn()
  cpufreq: drop redundant cpus_read_lock() from store_local_boost()
  cpupower: do not install files to /etc/default/
  cpupower: do not call systemctl at install time
  cpupower: do not write DESTDIR to cpupower.service
  PM: sleep: Introduce pm_sleep_transition_in_progress()
  cpufreq/amd-pstate: Avoid shadowing ret in amd_pstate_ut_check_driver()
  cpufreq: intel_pstate: Document hybrid processor support
  cpufreq: intel_pstate: EAS: Increase cost for CPUs using L3 cache
  cpufreq: intel_pstate: EAS support for hybrid platforms
  PM: EM: Introduce em_adjust_cpu_capacity()
  PM: EM: Move CPU capacity check to em_adjust_new_capacity()
  PM: EM: Documentation: Fix typos in example driver code
  cpufreq: Drop policy locking from cpufreq_policy_is_good_for_eas()
  PM: sleep: Introduce pm_suspend_in_progress()
  ...
2025-05-27 16:48:47 -07:00
Rafael J. Wysocki
af86d7e88e Merge branch 'pm-cpuidle'
Merge cpuidle updates for 6.16-rc1:

 - Optimize bucket assignment when next_timer_ns equals KTIME_MAX in the
   menu cpuidle governor (Zhongqiu Han).

 - Convert the cpuidle PSCI driver to a faux device one (Sudeep Holla).

 - Add C1 demotion on/off sysfs knob to the intel_idle driver (Artem
   Bityutskiy).

 - Fix typos in two comments in the teo cpuidle governor (Atul Kumar
   Pant).

* pm-cpuidle:
  cpuidle: psci: Avoid initializing faux device if no DT idle states are present
  Documentation: ABI: testing: document the new cpuidle sysfs file
  Documentation: admin-guide: pm: Document intel_idle C1 demotion
  intel_idle: Add C1 demotion on/off sysfs knob
  cpuidle: psci: Transition to the faux device interface
  cpuidle: menu: Optimize bucket assignment when next_timer_ns equals KTIME_MAX
  cpuidle: teo: Fix typos in two comments
2025-05-26 21:18:34 +02:00
Rafael J. Wysocki
f34dc28343 Merge branch 'pm-cpufreq'
Merge cpufreq updates for 6.16-rc1:

 - Refactor cpufreq_online(), add and use cpufreq policy locking guards,
   use __free() in policy reference counting, and clean up core cpufreq
   code on top of that (Rafael Wysocki).

 - Fix boost handling on CPU suspend/resume and sysfs updates (Viresh
   Kumar).

 - Fix des_perf clamping with max_perf in amd_pstate_update() (Dhananjay
   Ugwekar).

 - Add offline, online and suspend callbacks to the amd-pstate driver,
   rename and use the existing amd_pstate_epp callbacks in it (Dhananjay
   Ugwekar).

 - Add support for the "Requested CPU Min frequency" BIOS option to the
   amd-pstate driver (Dhananjay Ugwekar).

 - Reset amd-pstate driver mode after running selftests (Swapnil
   Sapkal).

 - Add helper for governor checks to the schedutil cpufreq governor and
   move cpufreq-specific EAS checks to cpufreq (Rafael Wysocki).

 - Populate the cpu_capacity sysfs entries from the intel_pstate driver
   after registering asym capacity support (Ricardo Neri).

 - Add support for enabling Energy-aware scheduling (EAS) to the
   intel_pstate driver when operating in the passive mode on a hybrid
   platform (Rafael Wysocki).

 - Avoid shadowing ret in amd_pstate_ut_check_driver() (Nathan
   Chancellor).

 - Drop redundant cpus_read_lock() from store_local_boost() in the
   cpufreq core (Seyediman Seyedarab).

 - Replace sscanf() with kstrtouint() in the cpufreq code and use a
   symbol instead of a raw number in it (Bowen Yu).

 - Add support for autonomous CPU performance state selection to the
   CPPC cpufreq driver (Lifeng Zheng).

* pm-cpufreq: (31 commits)
  cpufreq: CPPC: Add support for autonomous selection
  cpufreq: Update sscanf() to kstrtouint()
  cpufreq: Replace magic number
  cpufreq: drop redundant cpus_read_lock() from store_local_boost()
  cpufreq/amd-pstate: Avoid shadowing ret in amd_pstate_ut_check_driver()
  cpufreq: intel_pstate: Document hybrid processor support
  cpufreq: intel_pstate: EAS: Increase cost for CPUs using L3 cache
  cpufreq: intel_pstate: EAS support for hybrid platforms
  cpufreq: Drop policy locking from cpufreq_policy_is_good_for_eas()
  cpufreq: intel_pstate: Populate the cpu_capacity sysfs entries
  arch_topology: Relocate cpu_scale to topology.[h|c]
  cpufreq/sched: Move cpufreq-specific EAS checks to cpufreq
  cpufreq/sched: schedutil: Add helper for governor checks
  amd-pstate-ut: Reset amd-pstate driver mode after running selftests
  cpufreq/amd-pstate: Add support for the "Requested CPU Min frequency" BIOS option
  cpufreq/amd-pstate: Add offline, online and suspend callbacks for amd_pstate_driver
  cpufreq: Force sync policy boost with global boost on sysfs update
  cpufreq: Preserve policy's boost state after resume
  cpufreq: Introduce policy_set_boost()
  cpufreq: Don't unnecessarily call set_boost()
  ...
2025-05-26 20:19:40 +02:00
Lifeng Zheng
922607a2b4 cpufreq: CPPC: Add support for autonomous selection
Add sysfs interfaces for CPPC autonomous selection in the cppc_cpufreq
driver.

Signed-off-by: Lifeng Zheng <zhenglifeng1@huawei.com>
Reviewed-by: Sumit Gupta <sumitg@nvidia.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Link: https://patch.msgid.link/20250507031941.2812701-1-zhenglifeng1@huawei.com
[ rjw: Subject edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2025-05-21 22:47:44 +02:00
Ingo Molnar
c4070e1996 Merge commit 'its-for-linus-20250509-merge' into x86/core, to resolve conflicts
Conflicts:
	Documentation/admin-guide/hw-vuln/index.rst
	arch/x86/include/asm/cpufeatures.h
	arch/x86/kernel/alternative.c
	arch/x86/kernel/cpu/bugs.c
	arch/x86/kernel/cpu/common.c
	drivers/base/cpu.c
	include/linux/cpu.h

Signed-off-by: Ingo Molnar <mingo@kernel.org>
2025-05-13 10:47:10 +02:00
Pawan Gupta
f4818881c4 x86/its: Enable Indirect Target Selection mitigation
Indirect Target Selection (ITS) is a bug in some pre-ADL Intel CPUs with
eIBRS. It affects prediction of indirect branch and RETs in the
lower half of cacheline. Due to ITS such branches may get wrongly predicted
to a target of (direct or indirect) branch that is located in the upper
half of the cacheline.

Scope of impact
===============

Guest/host isolation
--------------------
When eIBRS is used for guest/host isolation, the indirect branches in the
VMM may still be predicted with targets corresponding to branches in the
guest.

Intra-mode
----------
cBPF or other native gadgets can be used for intra-mode training and
disclosure using ITS.

User/kernel isolation
---------------------
When eIBRS is enabled user/kernel isolation is not impacted.

Indirect Branch Prediction Barrier (IBPB)
-----------------------------------------
After an IBPB, indirect branches may be predicted with targets
corresponding to direct branches which were executed prior to IBPB. This is
mitigated by a microcode update.

Add cmdline parameter indirect_target_selection=off|on|force to control the
mitigation to relocate the affected branches to an ITS-safe thunk i.e.
located in the upper half of cacheline. Also add the sysfs reporting.

When retpoline mitigation is deployed, ITS safe-thunks are not needed,
because retpoline sequence is already ITS-safe. Similarly, when call depth
tracking (CDT) mitigation is deployed (retbleed=stuff), ITS safe return
thunk is not used, as CDT prevents RSB-underflow.

To not overcomplicate things, ITS mitigation is not supported with
spectre-v2 lfence;jmp mitigation. Moreover, it is less practical to deploy
lfence;jmp mitigation on ITS affected parts anyways.

Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Josh Poimboeuf <jpoimboe@kernel.org>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
2025-05-09 13:22:05 -07:00
Oliver Upton
17efc1acee arm64: Expose AIDR_EL1 via sysfs
The KVM PV ABI recently added a feature that allows the VM to discover
the set of physical CPU implementations, identified by a tuple of
{MIDR_EL1, REVIDR_EL1, AIDR_EL1}. Unlike other KVM PV features, the
expectation is that the VMM implements the hypercall instead of KVM as
it has the authoritative view of where the VM gets scheduled.

To do this the VMM needs to know the values of these registers on any
CPU in the system. While MIDR_EL1 and REVIDR_EL1 are already exposed,
AIDR_EL1 is not. Provide it in sysfs along with the other identification
registers.

Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Link: https://lore.kernel.org/r/20250403231626.3181116-1-oliver.upton@linux.dev
Signed-off-by: Will Deacon <will@kernel.org>
2025-04-29 14:03:18 +01:00
Dave Hansen
4e2c719782 x86/cpu: Help users notice when running old Intel microcode
Old microcode is bad for users and for kernel developers.

For users, it exposes them to known fixed security and/or functional
issues. These obviously rarely result in instant dumpster fires in
every environment. But it is as important to keep your microcode up
to date as it is to keep your kernel up to date.

Old microcode also makes kernels harder to debug. A developer looking
at an oops need to consider kernel bugs, known CPU issues and unknown
CPU issues as possible causes. If they know the microcode is up to
date, they can mostly eliminate known CPU issues as the cause.

Make it easier to tell if CPU microcode is out of date. Add a list
of released microcode. If the loaded microcode is older than the
release, tell users in a place that folks can find it:

	/sys/devices/system/cpu/vulnerabilities/old_microcode

Tell kernel kernel developers about it with the existing taint
flag:

	TAINT_CPU_OUT_OF_SPEC

== Discussion ==

When a user reports a potential kernel issue, it is very common
to ask them to reproduce the issue on mainline. Running mainline,
they will (independently from the distro) acquire a more up-to-date
microcode version list. If their microcode is old, they will
get a warning about the taint and kernel developers can take that
into consideration when debugging.

Just like any other entry in "vulnerabilities/", users are free to
make their own assessment of their exposure.

== Microcode Revision Discussion ==

The microcode versions in the table were generated from the Intel
microcode git repo:

	8ac9378a8487 ("microcode-20241112 Release")

which as of this writing lags behind the latest microcode-20250211.

It can be argued that the versions that the kernel picks to call "old"
should be a revision or two old. Which specific version is picked is
less important to me than picking *a* version and enforcing it.

This repository contains only microcode versions that Intel has deemed
to be OS-loadable. It is quite possible that the BIOS has loaded a
newer microcode than the latest in this repo. If this happens, the
system is considered to have new microcode, not old.

Specifically, the sysfs file and taint flag answer the question:

	Is the CPU running on the latest OS-loadable microcode,
	or something even later that the BIOS loaded?

In other words, Intel never publishes an authoritative list of CPUs
and latest microcode revisions. Until it does, this is the best that
Linux can do.

Also note that the "intel-ucode-defs.h" file is simple, ugly and
has lots of magic numbers. That's on purpose and should allow a
single file to be shared across lots of stable kernel regardless of if
they have the new "VFM" infrastructure or not. It was generated with
a dumb script.

== FAQ ==

Q: Does this tell me if my system is secure or insecure?
A: No. It only tells you if your microcode was old when the
   system booted.

Q: Should the kernel warn if the microcode list itself is too old?
A: No. New kernels will get new microcode lists, both mainline
   and stable. The only way to have an old list is to be running
   an old kernel in which case you have bigger problems.

Q: Is this for security or functional issues?
A: Both.

Q: If a given microcode update only has functional problems but
   no security issues, will it be considered old?
A: Yes. All microcode image versions within a microcode release
   are treated identically. Intel appears to make security
   updates without disclosing them in the release notes.  Thus,
   all updates are considered to be security-relevant.

Q: Who runs old microcode?
A: Anybody with an old distro. This happens all the time inside
   of Intel where there are lots of weird systems in labs that
   might not be getting regular distro updates and might also
   be running rather exotic microcode images.

Q: If I update my microcode after booting will it stop saying
   "Vulnerable"?
A: No. Just like all the other vulnerabilies, you need to
   reboot before the kernel will reassess your vulnerability.

Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: "Ahmed S. Darwish" <darwi@linutronix.de>
Cc: Andrew Cooper <andrew.cooper3@citrix.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: John Ogness <john.ogness@linutronix.de>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/all/20250421195659.CF426C07%40davehans-spike.ostc.intel.com
(cherry picked from commit 9127865b15eb0a1bd05ad7efe29489c44394bdc1)
2025-04-22 08:33:52 +02:00
Artem Bityutskiy
e80e1342ea Documentation: ABI: testing: document the new cpuidle sysfs file
Mention the new 'intel_c1_demotion' sysfs file in the "cpuidle" section
and refer to "Documentation/admin-guide/pm/intel_idle.rst" for more
information.

Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Link: https://patch.msgid.link/20250317135541.1471754-4-dedekind1@gmail.com
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2025-04-15 20:38:26 +02:00
Sourabh Jain
c91c6062d6 Document/kexec: generalize crash hotplug description
Commit 79365026f8 ("crash: add a new kexec flag for hotplug support")
generalizes the crash hotplug support to allow architectures to update
multiple kexec segments on CPU/Memory hotplug and not just elfcorehdr. 
Therefore, update the relevant kernel documentation to reflect the same.

No functional change.

Link: https://lkml.kernel.org/r/20240812041651.703156-1-sourabhjain@linux.ibm.com
Signed-off-by: Sourabh Jain <sourabhjain@linux.ibm.com>
Reviewed-by: Petr Tesarik <ptesarik@suse.com>
Acked-by: Baoquan He <bhe@redhat.com>
Cc: Hari Bathini <hbathini@linux.ibm.com>
Cc: Petr Tesarik <petr@tesarici.cz>
Cc: Sourabh Jain <sourabhjain@linux.ibm.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-09-01 20:43:37 -07:00
Nysal Jan K.A
6c17ea1f3e cpu/SMT: Enable SMT only if a core is online
If a core is offline then enabling SMT should not online CPUs of
this core. By enabling SMT, what is intended is either changing the SMT
value from "off" to "on" or setting the SMT level (threads per core) from a
lower to higher value.

On PowerPC the ppc64_cpu utility can be used, among other things, to
perform the following functions:

ppc64_cpu --cores-on                # Get the number of online cores
ppc64_cpu --cores-on=X              # Put exactly X cores online
ppc64_cpu --offline-cores=X[,Y,...] # Put specified cores offline
ppc64_cpu --smt={on|off|value}      # Enable, disable or change SMT level

If the user has decided to offline certain cores, enabling SMT should
not online CPUs in those cores. This patch fixes the issue and changes
the behaviour as described, by introducing an arch specific function
topology_is_core_online(). It is currently implemented only for PowerPC.

Fixes: 73c58e7e14 ("powerpc: Add HOTPLUG_SMT support")
Reported-by: Tyrel Datwyler <tyreld@linux.ibm.com>
Closes: https://groups.google.com/g/powerpc-utils-devel/c/wrwVzAAnRlI/m/5KJSoqP4BAAJ
Signed-off-by: Nysal Jan K.A <nysal@linux.ibm.com>
Reviewed-by: Shrikanth Hegde <sshegde@linux.ibm.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20240731030126.956210-2-nysal@linux.ibm.com
2024-08-13 10:31:24 +10:00
Linus Torvalds
408323581b - Add support for running the kernel in a SEV-SNP guest, over a Secure
VM Service Module (SVSM).
 
    When running over a SVSM, different services can run at different
    protection levels, apart from the guest OS but still within the
    secure SNP environment.  They can provide services to the guest, like
    a vTPM, for example.
 
    This series adds the required facilities to interface with such a SVSM
    module.
 
  - The usual fixlets, refactoring and cleanups
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Merge tag 'x86_sev_for_v6.11_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 SEV updates from Borislav Petkov:

 - Add support for running the kernel in a SEV-SNP guest, over a Secure
   VM Service Module (SVSM).

   When running over a SVSM, different services can run at different
   protection levels, apart from the guest OS but still within the
   secure SNP environment. They can provide services to the guest, like
   a vTPM, for example.

   This series adds the required facilities to interface with such a
   SVSM module.

 - The usual fixlets, refactoring and cleanups

[ And as always: "SEV" is AMD's "Secure Encrypted Virtualization".

  I can't be the only one who gets all the newer x86 TLA's confused,
  can I?
              - Linus ]

* tag 'x86_sev_for_v6.11_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  Documentation/ABI/configfs-tsm: Fix an unexpected indentation silly
  x86/sev: Do RMP memory coverage check after max_pfn has been set
  x86/sev: Move SEV compilation units
  virt: sev-guest: Mark driver struct with __refdata to prevent section mismatch
  x86/sev: Allow non-VMPL0 execution when an SVSM is present
  x86/sev: Extend the config-fs attestation support for an SVSM
  x86/sev: Take advantage of configfs visibility support in TSM
  fs/configfs: Add a callback to determine attribute visibility
  sev-guest: configfs-tsm: Allow the privlevel_floor attribute to be updated
  virt: sev-guest: Choose the VMPCK key based on executing VMPL
  x86/sev: Provide guest VMPL level to userspace
  x86/sev: Provide SVSM discovery support
  x86/sev: Use the SVSM to create a vCPU when not in VMPL0
  x86/sev: Perform PVALIDATE using the SVSM when not at VMPL0
  x86/sev: Use kernel provided SVSM Calling Areas
  x86/sev: Check for the presence of an SVSM in the SNP secrets page
  x86/irqflags: Provide native versions of the local_irq_save()/restore()
2024-07-16 11:12:25 -07:00
James Morse
4e1a7df454 cpumask: Add enabled cpumask for present CPUs that can be brought online
The 'offline' file in sysfs shows all offline CPUs, including those
that aren't present. User-space is expected to remove not-present CPUs
from this list to learn which CPUs could be brought online.

CPUs can be present but not-enabled. These CPUs can't be brought online
until the firmware policy changes, which comes with an ACPI notification
that will register the CPUs.

With only the offline and present files, user-space is unable to
determine which CPUs it can try to bring online. Add a new CPU mask
that shows this based on all the registered CPUs.

Signed-off-by: James Morse <james.morse@arm.com>
Tested-by: Miguel Luis <miguel.luis@oracle.com>
Tested-by: Vishnu Pajjuri <vishnu@os.amperecomputing.com>
Tested-by: Jianyong Wu <jianyong.wu@arm.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Reviewed-by: Gavin Shan <gshan@redhat.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Link: https://lore.kernel.org/r/20240529133446.28446-20-Jonathan.Cameron@huawei.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2024-06-28 18:38:33 +01:00
Tom Lendacky
61564d3468 x86/sev: Provide guest VMPL level to userspace
Requesting an attestation report from userspace involves providing the VMPL
level for the report. Currently any value from 0-3 is valid because Linux
enforces running at VMPL0.

When an SVSM is present, though, Linux will not be running at VMPL0 and only
VMPL values starting at the VMPL level Linux is running at to 3 are valid. In
order to allow userspace to determine the minimum VMPL value that can be
supplied to an attestation report, create a sysfs entry that can be used to
retrieve the current VMPL level of the kernel.

  [ bp: Add CONFIG_SYSFS ifdeffery. ]

Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/fff846da0d8d561f9fdaf297dcf8cd907545a25b.1717600736.git.thomas.lendacky@amd.com
2024-06-17 20:42:57 +02:00
Stephen Rothwell
fae573060c Documentation: Fix the address of the linuxppc-dev mailing list
This list was moved many years ago.

Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20240503121012.3ba5000b@canb.auug.org.au
2024-05-06 22:05:18 +10:00
Pawan Gupta
8076fcde01 x86/rfds: Mitigate Register File Data Sampling (RFDS)
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>
2024-03-11 13:13:48 -07:00
Ard Biesheuvel
944834901a Documentation: Drop or replace remaining mentions of IA64
Drop or update mentions of IA64, as appropriate.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2023-09-11 08:13:18 +00:00
Linus Torvalds
d68b4b6f30 - 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
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Merge tag 'mm-nonmm-stable-2023-08-28-22-48' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull non-MM updates from Andrew Morton:

 - An extensive rework of kexec and crash Kconfig from Eric DeVolder
   ("refactor Kconfig to consolidate KEXEC and CRASH options")

 - kernel.h slimming work from Andy Shevchenko ("kernel.h: Split out a
   couple of macros to args.h")

 - gdb feature work from Kuan-Ying Lee ("Add GDB memory helper
   commands")

 - vsprintf inclusion rationalization from Andy Shevchenko
   ("lib/vsprintf: Rework header inclusions")

 - Switch the handling of kdump from a udev scheme to in-kernel
   handling, by Eric DeVolder ("crash: Kernel handling of CPU and memory
   hot un/plug")

 - Many singleton patches to various parts of the tree

* tag 'mm-nonmm-stable-2023-08-28-22-48' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (81 commits)
  document while_each_thread(), change first_tid() to use for_each_thread()
  drivers/char/mem.c: shrink character device's devlist[] array
  x86/crash: optimize CPU changes
  crash: change crash_prepare_elf64_headers() to for_each_possible_cpu()
  crash: hotplug support for kexec_load()
  x86/crash: add x86 crash hotplug support
  crash: memory and CPU hotplug sysfs attributes
  kexec: exclude elfcorehdr from the segment digest
  crash: add generic infrastructure for crash hotplug support
  crash: move a few code bits to setup support of crash hotplug
  kstrtox: consistently use _tolower()
  kill do_each_thread()
  nilfs2: fix WARNING in mark_buffer_dirty due to discarded buffer reuse
  scripts/bloat-o-meter: count weak symbol sizes
  treewide: drop CONFIG_EMBEDDED
  lockdep: fix static memory detection even more
  lib/vsprintf: declare no_hash_pointers in sprintf.h
  lib/vsprintf: split out sprintf() and friends
  kernel/fork: stop playing lockless games for exe_file replacement
  adfs: delete unused "union adfs_dirtail" definition
  ...
2023-08-29 14:53:51 -07:00
Linus Torvalds
6f49693a6c Updates for the CPU hotplug core:
- Support partial SMT enablement.
 
     So far the sysfs SMT control only allows to toggle between SMT on and
     off. That's sufficient for x86 which usually has at max two threads
     except for the Xeon PHI platform which has four threads per core.
 
     Though PowerPC has up to 16 threads per core and so far it's only
     possible to control the number of enabled threads per core via a
     command line option. There is some way to control this at runtime, but
     that lacks enforcement and the usability is awkward.
 
     This update expands the sysfs interface and the core infrastructure to
     accept numerical values so PowerPC can build SMT runtime control for
     partial SMT enablement on top.
 
     The core support has also been provided to the PowerPC maintainers who
     added the PowerPC related changes on top.
 
   - Minor cleanups and documentation updates.
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Merge tag 'smp-core-2023-08-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull CPU hotplug updates from Thomas Gleixner:
 "Updates for the CPU hotplug core:

   - Support partial SMT enablement.

     So far the sysfs SMT control only allows to toggle between SMT on
     and off. That's sufficient for x86 which usually has at max two
     threads except for the Xeon PHI platform which has four threads per
     core

     Though PowerPC has up to 16 threads per core and so far it's only
     possible to control the number of enabled threads per core via a
     command line option. There is some way to control this at runtime,
     but that lacks enforcement and the usability is awkward

     This update expands the sysfs interface and the core infrastructure
     to accept numerical values so PowerPC can build SMT runtime control
     for partial SMT enablement on top

     The core support has also been provided to the PowerPC maintainers
     who added the PowerPC related changes on top

   - Minor cleanups and documentation updates"

* tag 'smp-core-2023-08-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  Documentation: core-api/cpuhotplug: Fix state names
  cpu/hotplug: Remove unused function declaration cpu_set_state_online()
  cpu/SMT: Fix cpu_smt_possible() comment
  cpu/SMT: Allow enabling partial SMT states via sysfs
  cpu/SMT: Create topology_smt_thread_allowed()
  cpu/SMT: Remove topology_smt_supported()
  cpu/SMT: Store the current/max number of threads
  cpu/SMT: Move smt/control simple exit cases earlier
  cpu/SMT: Move SMT prototypes into cpu_smt.h
  cpu/hotplug: Remove dependancy against cpu_primary_thread_mask
2023-08-28 15:04:43 -07:00
Eric DeVolder
88a6f89944 crash: memory and CPU hotplug sysfs attributes
Introduce the crash_hotplug attribute for memory and CPUs for use by
userspace.  These attributes directly facilitate the udev rule for
managing userspace re-loading of the crash kernel upon hot un/plug
changes.

For memory, expose the crash_hotplug attribute to the
/sys/devices/system/memory directory.  For example:

 # udevadm info --attribute-walk /sys/devices/system/memory/memory81
  looking at device '/devices/system/memory/memory81':
    KERNEL=="memory81"
    SUBSYSTEM=="memory"
    DRIVER==""
    ATTR{online}=="1"
    ATTR{phys_device}=="0"
    ATTR{phys_index}=="00000051"
    ATTR{removable}=="1"
    ATTR{state}=="online"
    ATTR{valid_zones}=="Movable"

  looking at parent device '/devices/system/memory':
    KERNELS=="memory"
    SUBSYSTEMS==""
    DRIVERS==""
    ATTRS{auto_online_blocks}=="offline"
    ATTRS{block_size_bytes}=="8000000"
    ATTRS{crash_hotplug}=="1"

For CPUs, expose the crash_hotplug attribute to the
/sys/devices/system/cpu directory. For example:

 # udevadm info --attribute-walk /sys/devices/system/cpu/cpu0
  looking at device '/devices/system/cpu/cpu0':
    KERNEL=="cpu0"
    SUBSYSTEM=="cpu"
    DRIVER=="processor"
    ATTR{crash_notes}=="277c38600"
    ATTR{crash_notes_size}=="368"
    ATTR{online}=="1"

  looking at parent device '/devices/system/cpu':
    KERNELS=="cpu"
    SUBSYSTEMS==""
    DRIVERS==""
    ATTRS{crash_hotplug}=="1"
    ATTRS{isolated}==""
    ATTRS{kernel_max}=="8191"
    ATTRS{nohz_full}=="  (null)"
    ATTRS{offline}=="4-7"
    ATTRS{online}=="0-3"
    ATTRS{possible}=="0-7"
    ATTRS{present}=="0-3"

With these sysfs attributes in place, it is possible to efficiently
instruct the udev rule to skip crash kernel reloading for kernels
configured with crash hotplug support.

For example, the following is the proposed udev rule change for RHEL
system 98-kexec.rules (as the first lines of the rule file):

 # The kernel updates the crash elfcorehdr for CPU and memory changes
 SUBSYSTEM=="cpu", ATTRS{crash_hotplug}=="1", GOTO="kdump_reload_end"
 SUBSYSTEM=="memory", ATTRS{crash_hotplug}=="1", GOTO="kdump_reload_end"

When examined in the context of 98-kexec.rules, the above rules test if
crash_hotplug is set, and if so, the userspace initiated
unload-then-reload of the crash kernel is skipped.

CPU and memory checks are separated in accordance with CONFIG_HOTPLUG_CPU
and CONFIG_MEMORY_HOTPLUG kernel config options.  If an architecture
supports, for example, memory hotplug but not CPU hotplug, then the
/sys/devices/system/memory/crash_hotplug attribute file is present, but
the /sys/devices/system/cpu/crash_hotplug attribute file will NOT be
present.  Thus the udev rule skips userspace processing of memory hot
un/plug events, but the udev rule will evaluate false for CPU events, thus
allowing userspace to process CPU hot un/plug events (ie the
unload-then-reload of the kdump capture kernel).

Link: https://lkml.kernel.org/r/20230814214446.6659-5-eric.devolder@oracle.com
Signed-off-by: Eric DeVolder <eric.devolder@oracle.com>
Reviewed-by: Sourabh Jain <sourabhjain@linux.ibm.com>
Acked-by: Hari Bathini <hbathini@linux.ibm.com>
Acked-by: Baoquan He <bhe@redhat.com>
Cc: Akhil Raj <lf32.dev@gmail.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Borislav Petkov (AMD) <bp@alien8.de>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Mimi Zohar <zohar@linux.ibm.com>
Cc: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Sean Christopherson <seanjc@google.com>
Cc: Takashi Iwai <tiwai@suse.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Thomas Weißschuh <linux@weissschuh.net>
Cc: Valentin Schneider <vschneid@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-08-24 16:25:14 -07:00
Michael Ellerman
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
2023-07-28 09:53:37 +02:00
Daniel Sneddon
8974eb5882 x86/speculation: Add Gather Data Sampling mitigation
Gather Data Sampling (GDS) is a hardware vulnerability which allows
unprivileged speculative access to data which was previously stored in
vector registers.

Intel processors that support AVX2 and AVX512 have gather instructions
that fetch non-contiguous data elements from memory. On vulnerable
hardware, when a gather instruction is transiently executed and
encounters a fault, stale data from architectural or internal vector
registers may get transiently stored to the destination vector
register allowing an attacker to infer the stale data using typical
side channel techniques like cache timing attacks.

This mitigation is different from many earlier ones for two reasons.
First, it is enabled by default and a bit must be set to *DISABLE* it.
This is the opposite of normal mitigation polarity. This means GDS can
be mitigated simply by updating microcode and leaving the new control
bit alone.

Second, GDS has a "lock" bit. This lock bit is there because the
mitigation affects the hardware security features KeyLocker and SGX.
It needs to be enabled and *STAY* enabled for these features to be
mitigated against GDS.

The mitigation is enabled in the microcode by default. Disable it by
setting gather_data_sampling=off or by disabling all mitigations with
mitigations=off. The mitigation status can be checked by reading:

    /sys/devices/system/cpu/vulnerabilities/gather_data_sampling

Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
2023-07-19 16:45:37 -07:00
Jonathan Corbet
e4624435f3 docs: arm64: Move arm64 documentation under Documentation/arch/
Architecture-specific documentation is being moved into Documentation/arch/
as a way of cleaning up the top-level documentation directory and making
the docs hierarchy more closely match the source hierarchy.  Move
Documentation/arm64 into arch/ (along with the Chinese equvalent
translations) and fix up documentation references.

Cc: Will Deacon <will@kernel.org>
Cc: Alex Shi <alexs@kernel.org>
Cc: Hu Haowen <src.res@email.cn>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Yantengsi <siyanteng@loongson.cn>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2023-06-21 08:51:51 -06:00
Linus Torvalds
f3dfe925f9 There's not a huge amount of activity in the docs tree this time around,
but a few significant changes even so:
 
 - A complete rewriting of the top-level index.rst file, which mostly
   reflects itself in a redone top page in the HTML-rendered docs.  The hope
   is that the new organization will be a friendlier starting point for
   both users and developers.
 
 - Some math-rendering improvements.
 
 - A coding-style.rst update on the use of BUG() and WARN()
 
 - A big maintainer-PHP guide update.
 
 - Some code-of-conduct updates
 
 - More Chinese translation work
 
 Plus the usual pile of typo fixes, corrections, and updates.
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Merge tag 'docs-6.1' of git://git.lwn.net/linux

Pull documentation updates from Jonathan Corbet:
 "There's not a huge amount of activity in the docs tree this time
  around, but a few significant changes even so:

   - A complete rewriting of the top-level index.rst file, which mostly
     reflects itself in a redone top page in the HTML-rendered docs. The
     hope is that the new organization will be a friendlier starting
     point for both users and developers.

   - Some math-rendering improvements.

   - A coding-style.rst update on the use of BUG() and WARN()

   - A big maintainer-PHP guide update.

   - Some code-of-conduct updates

   - More Chinese translation work

  Plus the usual pile of typo fixes, corrections, and updates"

* tag 'docs-6.1' of git://git.lwn.net/linux: (66 commits)
  checkpatch: warn on usage of VM_BUG_ON() and other BUG variants
  coding-style.rst: document BUG() and WARN() rules ("do not crash the kernel")
  Documentation: devres: add missing IO helper
  Documentation: devres: update IRQ helper
  Documentation/mm: modify page_referenced to folio_referenced
  Documentation/CoC: Reflect current CoC interpretation and practices
  docs/doc-guide: Add documentation on SPHINX_IMGMATH
  docs: process/5.Posting.rst: clarify use of Reported-by: tag
  docs, kprobes: Fix the wrong location of Kprobes
  docs: add a man-pages link to the front page
  docs: put atomic*.txt and memory-barriers.txt into the core-api book
  docs: move asm-annotations.rst into core-api
  docs: remove some index.rst cruft
  docs: reconfigure the HTML left column
  docs: Rewrite the front page
  docs: promote the title of process/index.rst
  Documentation: devres: add missing SPI helper
  Documentation: devres: add missing PINCTRL helpers
  docs: hugetlbpage.rst: fix a typo of hugepage size
  docs/zh_CN: Add new translation of admin-guide/bootconfig.rst
  ...
2022-10-03 10:23:32 -07:00
Randy Dunlap
8a7f0e8ab9 Documentation/ABI: correct possessive "its" typos
Correct all uses of "it's" that are meant to be possessive "its".

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/20220801025207.29971-1-rdunlap@infradead.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2022-09-27 13:21:43 -06:00
Salvatore Bonaccorso
00da0cb385 Documentation/ABI: Mention retbleed vulnerability info file for sysfs
While reporting for the AMD retbleed vulnerability was added in

  6b80b59b35 ("x86/bugs: Report AMD retbleed vulnerability")

the new sysfs file was not mentioned so far in the ABI documentation for
sysfs-devices-system-cpu. Fix that.

Fixes: 6b80b59b35 ("x86/bugs: Report AMD retbleed vulnerability")
Signed-off-by: Salvatore Bonaccorso <carnil@debian.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20220801091529.325327-1-carnil@debian.org
2022-08-25 15:55:02 +02:00
Linus Torvalds
cfeafd9466 Driver core / kernfs changes for 6.0-rc1
Here is the set of driver core and kernfs changes for 6.0-rc1.
 
 "biggest" thing in here is some scalability improvements for kernfs for
 large systems.  Other than that, included in here are:
 	- arch topology and cache info changes that have been reviewed
 	  and discussed a lot.
 	- potential error path cleanup fixes
 	- deferred driver probe cleanups
 	- firmware loader cleanups and tweaks
 	- documentation updates
 	- other small things
 
 All of these have been in the linux-next tree for a while with no
 reported problems.
 
 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'driver-core-6.0-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core

Pull driver core / kernfs updates from Greg KH:
 "Here is the set of driver core and kernfs changes for 6.0-rc1.

  The "biggest" thing in here is some scalability improvements for
  kernfs for large systems. Other than that, included in here are:

   - arch topology and cache info changes that have been reviewed and
     discussed a lot.

   - potential error path cleanup fixes

   - deferred driver probe cleanups

   - firmware loader cleanups and tweaks

   - documentation updates

   - other small things

  All of these have been in the linux-next tree for a while with no
  reported problems"

* tag 'driver-core-6.0-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (63 commits)
  docs: embargoed-hardware-issues: fix invalid AMD contact email
  firmware_loader: Replace kmap() with kmap_local_page()
  sysfs docs: ABI: Fix typo in comment
  kobject: fix Kconfig.debug "its" grammar
  kernfs: Fix typo 'the the' in comment
  docs: driver-api: firmware: add driver firmware guidelines. (v3)
  arch_topology: Fix cache attributes detection in the CPU hotplug path
  ACPI: PPTT: Leave the table mapped for the runtime usage
  cacheinfo: Use atomic allocation for percpu cache attributes
  drivers/base: fix userspace break from using bin_attributes for cpumap and cpulist
  MAINTAINERS: Change mentions of mpm to olivia
  docs: ABI: sysfs-devices-soc: Update Lee Jones' email address
  docs: ABI: sysfs-class-pwm: Update Lee Jones' email address
  Documentation/process: Add embargoed HW contact for LLVM
  Revert "kernfs: Change kernfs_notify_list to llist."
  ACPI: Remove the unused find_acpi_cpu_cache_topology()
  arch_topology: Warn that topology for nested clusters is not supported
  arch_topology: Add support for parsing sockets in /cpu-map
  arch_topology: Set cluster identifier in each core/thread from /cpu-map
  arch_topology: Limit span of cpu_clustergroup_mask()
  ...
2022-08-04 11:31:20 -07:00
Mauro Carvalho Chehab
1d248d2302 ABI: testing/sysfs-devices-system-cpu: remove duplicated core_id
This was already defined at stable/sysfs-devices-system-cpu with
the same description, as pointed by get_abi.pl:

	Warning: /sys/devices/system/cpu/cpuX/topology/core_id is defined 2 times:  Documentation/ABI/stable/sysfs-devices-system-cpu:38  Documentation/ABI/testing/sysfs-devices-system-cpu:69

Remove the duplicated one.

Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>
Link: https://lore.kernel.org/r/1e92337c1ef74f5eb9e1c1871e20b858b490d269.1656235926.git.mchehab@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-06-27 16:43:11 +02:00
Mark Brown
d69d564964 arm64/sme: Expose SMIDR through sysfs
We currently expose MIDR and REVID to userspace through sysfs to enable it
to make decisions based on the specific implementation. Since SME supports
implementations where streaming mode is provided by a separate hardware
unit called a SMCU it provides a similar ID register SMIDR. Expose it to
userspace via sysfs when the system supports SME along with the other ID
registers.

Since we disable the SME priority mapping feature if it is supported by
hardware we currently mask out the SMPS bit which reports that it is
supported.

Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20220607132857.1358361-1-broonie@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
2022-06-23 18:22:44 +01:00
Pawan Gupta
8d50cdf8b8 x86/speculation/mmio: Add sysfs reporting for Processor MMIO Stale Data
Add the sysfs reporting file for Processor MMIO Stale Data
vulnerability. It exposes the vulnerability and mitigation state similar
to the existing files for the other hardware vulnerabilities.

Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
2022-05-21 12:16:04 +02:00
Linus Torvalds
d752e21114 - Merge the AMD and Intel PPIN code into a shared one by both vendors.
Add the PPIN number to sysfs so that sockets can be identified when
 replacement is needed
 
 - Minor fixes and cleanups
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Merge tag 'x86_cpu_for_v5.18_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 cpu feature updates from Borislav Petkov:

 - Merge the AMD and Intel PPIN code into a shared one by both vendors.
   Add the PPIN number to sysfs so that sockets can be identified when
   replacement is needed

 - Minor fixes and cleanups

* tag 'x86_cpu_for_v5.18_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/cpu: Clear SME feature flag when not in use
  x86/cpufeatures: Put the AMX macros in the word 18 block
  topology/sysfs: Add PPIN in sysfs under cpu topology
  topology/sysfs: Add format parameter to macro defining "show" functions for proc
  x86/cpu: Read/save PPIN MSR during initialization
  x86/cpu: X86_FEATURE_INTEL_PPIN finally has a CPUID bit
  x86/cpu: Merge Intel and AMD ppin_init() functions
  x86/CPU/AMD: Use default_groups in kobj_type
2022-03-21 11:11:48 -07:00
Evgenii Stepanov
9986c7650e docs: sysfs-devices-system-cpu: document "asymm" value for mte_tcf_preferred
It was added in commit 766121ba5d ("arm64/mte: Add userspace interface
for enabling asymmetric mode").

Signed-off-by: Evgenii Stepanov <eugenis@google.com>
Reviewed-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20220309215943.87831-1-eugenis@google.com
Signed-off-by: Will Deacon <will@kernel.org>
2022-03-10 10:23:10 +00:00
Tony Luck
ab28e94419 topology/sysfs: Add PPIN in sysfs under cpu topology
PPIN is the Protected Processor Identification Number.
This is used to identify the socket as a Field Replaceable Unit (FRU).

Existing code only displays this when reporting errors. But this makes
it inconvenient for large clusters to use it for its intended purpose
of inventory control.

Add ppin to /sys/devices/system/cpu/cpu*/topology to make what
is already available using RDMSR more easily accessible. Make
the file read only for root in case there are still people
concerned about making a unique system "serial number" available.

Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/20220131230111.2004669-6-tony.luck@intel.com
2022-02-01 16:36:42 +01:00
Kohei Tarumizu
02bf607413 docs: document the sysfs ABI for "isolated"
Add missing documentation of sysfs ABI for "isolated". It was added by
commit 59f30abe94bf("show isolated cpus in sysfs"). However, there is
no documentation for these interface.

Signed-off-by: Kohei Tarumizu <tarumizu.kohei@fujitsu.com>
Link: https://lore.kernel.org/r/20211201115957.254224-3-tarumizu.kohei@fujitsu.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-12-03 14:35:17 +01:00
Kohei Tarumizu
3722e7c3c6 docs: document the sysfs ABI for "nohz_full"
Add missing documentation of sysfs ABI for "nohz_full". It was added
by commit 6570a9a1ce3a("show nohz_full cpus in sysfs"). However,
there is no documentation for these interface.

Signed-off-by: Kohei Tarumizu <tarumizu.kohei@fujitsu.com>
Link: https://lore.kernel.org/r/20211201115957.254224-2-tarumizu.kohei@fujitsu.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-12-03 14:35:17 +01:00
Mauro Carvalho Chehab
abcb948db3 ABI: sysfs-devices-system-cpu: use cpuX instead of cpu#
Some What entries here use cpu# as a wildcard, while others
use, instead, cpuX.

As scripts/get_abi.pl doesn't consider "#" as a wildcard,
replace:

	cpu# -> cpuX

inside the file.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/60b1a79189d1a9d9f1c9c9c299770e69b18972fd.1632994837.git.mchehab+huawei@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-10-05 16:25:27 +02:00
Mauro Carvalho Chehab
26d6ba2f89 ABI: sysfs-devices-system-cpu: use wildcards on What definitions
An "N" upper letter is not a wildcard, nor can easily be identified
by script, specially since the USB sysfs define things like.
bNumInterfaces. Use, instead, <N>, in order to let script/get_abi.pl
to convert it into a Regex.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/d18385a391b6797373a5d1382ea024857fb29987.1631782432.git.mchehab+huawei@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-09-21 18:31:17 +02:00
Catalin Marinas
65266a7c6a Merge remote-tracking branch 'tip/sched/arm64' into for-next/core
* tip/sched/arm64: (785 commits)
  Documentation: arm64: describe asymmetric 32-bit support
  arm64: Remove logic to kill 32-bit tasks on 64-bit-only cores
  arm64: Hook up cmdline parameter to allow mismatched 32-bit EL0
  arm64: Advertise CPUs capable of running 32-bit applications in sysfs
  arm64: Prevent offlining first CPU with 32-bit EL0 on mismatched system
  arm64: exec: Adjust affinity for compat tasks with mismatched 32-bit EL0
  arm64: Implement task_cpu_possible_mask()
  sched: Introduce dl_task_check_affinity() to check proposed affinity
  sched: Allow task CPU affinity to be restricted on asymmetric systems
  sched: Split the guts of sched_setaffinity() into a helper function
  sched: Introduce task_struct::user_cpus_ptr to track requested affinity
  sched: Reject CPU affinity changes based on task_cpu_possible_mask()
  cpuset: Cleanup cpuset_cpus_allowed_fallback() use in select_fallback_rq()
  cpuset: Honour task_cpu_possible_mask() in guarantee_online_cpus()
  cpuset: Don't use the cpu_possible_mask as a last resort for cgroup v1
  sched: Introduce task_cpu_possible_mask() to limit fallback rq selection
  sched: Cgroup SCHED_IDLE support
  sched/topology: Skip updating masks for non-online nodes
  Linux 5.14-rc6
  lib: use PFN_PHYS() in devmem_is_allowed()
  ...
2021-08-31 09:10:00 +01:00
Will Deacon
7af33504d1 arm64: Advertise CPUs capable of running 32-bit applications in sysfs
Since 32-bit applications will be killed if they are caught trying to
execute on a 64-bit-only CPU in a mismatched system, advertise the set
of 32-bit capable CPUs to userspace in sysfs.

Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20210730112443.23245-14-will@kernel.org
2021-08-20 12:33:07 +02:00
Peter Collingbourne
80c7c36fb3 Documentation: document the preferred tag checking mode feature
Document the functionality added in the previous patches.

Link: https://linux-review.googlesource.com/id/I48217cc3e8b8da33abc08cbaddc11cf4360a1b86
Signed-off-by: Peter Collingbourne <pcc@google.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20210727205300.2554659-6-pcc@google.com
Acked-by: Will Deacon <will@kernel.org>
[catalin.marinas@arm.com: clarify that the change happens on task scheduling]
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2021-07-28 18:39:26 +01:00
Carlos Bilbao
3e42d1de02 docs: typo fixes in Documentation/ABI/
Fix the following typos in the Documentation/ABI/ directory:

- In file obsolete/sysfs-cpuidle, change "obselete" for "obsolete".

- In file removed/sysfs-kernel-uids, change "propotional" for "proportional".

- In directory stable/, fix the following words: "associtated" for "associated",
  "hexidecimal" for "hexadecimal", "vlue" for "value", "csed" for "caused" and
  "wrtie" for "write". This updates a total of five files.

- In directory testing/, fix the following words: "subystem" for "subsystem",
  "isochrnous" for "isochronous", "Desctiptors" for "Descriptors", "picutre" for
  "picture", "capture" for "capture", "occured" for "ocurred", "connnected" for
  "connected","agressively" for "aggressively","manufacturee" for "manufacturer"
  and "transaction" for "transaction", "malformatted" for "incorrectly formated"
  ,"internel" for "internal", "writtento" for "written to", "specificed" for
  "specified", "beyound" for "beyond", "Symetric" for "Symmetric". This updates
  a total of eleven files.

Signed-off-by: Carlos Bilbao <bilbao@vt.edu>
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
Reviewed-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/5710038.lOV4Wx5bFT@iron-maiden
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2021-05-13 09:13:25 -06:00
Anatoly Pugachev
2fa4928aed docs: correct URL to bios and kernel developer's guide
correct URL to bios and kernel developer's guide on amd.com site

Signed-off-by: Anatoly Pugachev <matorola@gmail.com>
Link: https://lore.kernel.org/r/20210428104851.GA10572@u164.east.ru
[jc: fixed resulting sphinx warning]
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2021-05-03 17:22:44 -06:00
Ionela Voinescu
cfdc589f4b cppc_cpufreq: expose information on frequency domains
Use the existing sysfs attribute "freqdomain_cpus" to expose
information to userspace about CPUs in the same frequency domain.

Signed-off-by: Ionela Voinescu <ionela.voinescu@arm.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Tested-by: Mian Yousaf Kaukab <ykaukab@suse.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2020-12-15 19:19:32 +01:00
Mauro Carvalho Chehab
54a19b4d3f docs: ABI: cleanup several ABI documents
There are some ABI documents that, while they don't generate
any warnings, they have issues when parsed by get_abi.pl script
on its output result.

Address them, in order to provide a clean output.

Reviewed-by: Tom Rix <trix@redhat.com> # for fpga-manager
Reviewed-By: Kajol Jain<kjain@linux.ibm.com> # for sysfs-bus-event_source-devices-hv_gpci and sysfs-bus-event_source-devices-hv_24x7
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> #for IIO
Acked-by: Oded Gabbay <oded.gabbay@gmail.com> # for Habanalabs
Acked-by: Vaibhav Jain <vaibhav@linux.ibm.com> # for sysfs-bus-papr-pmem
Acked-by: Cezary Rojewski <cezary.rojewski@intel.com> # for catpt
Acked-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Acked-by: Ilya Dryomov <idryomov@gmail.com> # for rbd
Acked-by: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/5bc78e5b68ed1e9e39135173857cb2e753be868f.1604042072.git.mchehab+huawei@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-10-30 13:14:29 +01:00
Mauro Carvalho Chehab
3443333284 docs: ABI: testing: make the files compatible with ReST output
Some files over there won't parse well by Sphinx.

Fix them.

Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> # for IIO
Acked-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Acked-by: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/58cf3c2d611e0197fb215652719ebd82ca2658db.1604042072.git.mchehab+huawei@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-10-30 13:07:01 +01:00
Linus Torvalds
8b4d37db9a Merge branch 'x86/srbds' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 srbds fixes from Thomas Gleixner:
 "The 9th episode of the dime novel "The performance killer" with the
  subtitle "Slow Randomizing Boosts Denial of Service".

  SRBDS is an MDS-like speculative side channel that can leak bits from
  the random number generator (RNG) across cores and threads. New
  microcode serializes the processor access during the execution of
  RDRAND and RDSEED. This ensures that the shared buffer is overwritten
  before it is released for reuse. This is equivalent to a full bus
  lock, which means that many threads running the RNG instructions in
  parallel have the same effect as the same amount of threads issuing a
  locked instruction targeting an address which requires locking of two
  cachelines at once.

  The mitigation support comes with the usual pile of unpleasant
  ingredients:

   - command line options

   - sysfs file

   - microcode checks

   - a list of vulnerable CPUs identified by model and stepping this
     time which requires stepping match support for the cpu match logic.

   - the inevitable slowdown of affected CPUs"

* branch 'x86/srbds' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/speculation: Add Ivy Bridge to affected list
  x86/speculation: Add SRBDS vulnerability and mitigation documentation
  x86/speculation: Add Special Register Buffer Data Sampling (SRBDS) mitigation
  x86/cpu: Add 'table' argument to cpu_matches()
2020-06-09 09:30:21 -07:00
Linus Torvalds
7ae77150d9 powerpc updates for 5.8
- Support for userspace to send requests directly to the on-chip GZIP
    accelerator on Power9.
 
  - Rework of our lockless page table walking (__find_linux_pte()) to make it
    safe against parallel page table manipulations without relying on an IPI for
    serialisation.
 
  - A series of fixes & enhancements to make our machine check handling more
    robust.
 
  - Lots of plumbing to add support for "prefixed" (64-bit) instructions on
    Power10.
 
  - Support for using huge pages for the linear mapping on 8xx (32-bit).
 
  - Remove obsolete Xilinx PPC405/PPC440 support, and an associated sound driver.
 
  - Removal of some obsolete 40x platforms and associated cruft.
 
  - Initial support for booting on Power10.
 
  - Lots of other small features, cleanups & fixes.
 
 Thanks to:
   Alexey Kardashevskiy, Alistair Popple, Andrew Donnellan, Andrey Abramov,
   Aneesh Kumar K.V, Balamuruhan S, Bharata B Rao, Bulent Abali, Cédric Le
   Goater, Chen Zhou, Christian Zigotzky, Christophe JAILLET, Christophe Leroy,
   Dmitry Torokhov, Emmanuel Nicolet, Erhard F., Gautham R. Shenoy, Geoff Levand,
   George Spelvin, Greg Kurz, Gustavo A. R. Silva, Gustavo Walbon, Haren Myneni,
   Hari Bathini, Joel Stanley, Jordan Niethe, Kajol Jain, Kees Cook, Leonardo
   Bras, Madhavan Srinivasan., Mahesh Salgaonkar, Markus Elfring, Michael
   Neuling, Michal Simek, Nathan Chancellor, Nathan Lynch, Naveen N. Rao,
   Nicholas Piggin, Oliver O'Halloran, Paul Mackerras, Pingfan Liu, Qian Cai, Ram
   Pai, Raphael Moreira Zinsly, Ravi Bangoria, Sam Bobroff, Sandipan Das, Segher
   Boessenkool, Stephen Rothwell, Sukadev Bhattiprolu, Tyrel Datwyler, Wolfram
   Sang, Xiongfeng Wang.
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Merge tag 'powerpc-5.8-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux

Pull powerpc updates from Michael Ellerman:

 - Support for userspace to send requests directly to the on-chip GZIP
   accelerator on Power9.

 - Rework of our lockless page table walking (__find_linux_pte()) to
   make it safe against parallel page table manipulations without
   relying on an IPI for serialisation.

 - A series of fixes & enhancements to make our machine check handling
   more robust.

 - Lots of plumbing to add support for "prefixed" (64-bit) instructions
   on Power10.

 - Support for using huge pages for the linear mapping on 8xx (32-bit).

 - Remove obsolete Xilinx PPC405/PPC440 support, and an associated sound
   driver.

 - Removal of some obsolete 40x platforms and associated cruft.

 - Initial support for booting on Power10.

 - Lots of other small features, cleanups & fixes.

Thanks to: Alexey Kardashevskiy, Alistair Popple, Andrew Donnellan,
Andrey Abramov, Aneesh Kumar K.V, Balamuruhan S, Bharata B Rao, Bulent
Abali, Cédric Le Goater, Chen Zhou, Christian Zigotzky, Christophe
JAILLET, Christophe Leroy, Dmitry Torokhov, Emmanuel Nicolet, Erhard F.,
Gautham R. Shenoy, Geoff Levand, George Spelvin, Greg Kurz, Gustavo A.
R. Silva, Gustavo Walbon, Haren Myneni, Hari Bathini, Joel Stanley,
Jordan Niethe, Kajol Jain, Kees Cook, Leonardo Bras, Madhavan
Srinivasan., Mahesh Salgaonkar, Markus Elfring, Michael Neuling, Michal
Simek, Nathan Chancellor, Nathan Lynch, Naveen N. Rao, Nicholas Piggin,
Oliver O'Halloran, Paul Mackerras, Pingfan Liu, Qian Cai, Ram Pai,
Raphael Moreira Zinsly, Ravi Bangoria, Sam Bobroff, Sandipan Das, Segher
Boessenkool, Stephen Rothwell, Sukadev Bhattiprolu, Tyrel Datwyler,
Wolfram Sang, Xiongfeng Wang.

* tag 'powerpc-5.8-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (299 commits)
  powerpc/pseries: Make vio and ibmebus initcalls pseries specific
  cxl: Remove dead Kconfig options
  powerpc: Add POWER10 architected mode
  powerpc/dt_cpu_ftrs: Add MMA feature
  powerpc/dt_cpu_ftrs: Enable Prefixed Instructions
  powerpc/dt_cpu_ftrs: Advertise support for ISA v3.1 if selected
  powerpc: Add support for ISA v3.1
  powerpc: Add new HWCAP bits
  powerpc/64s: Don't set FSCR bits in INIT_THREAD
  powerpc/64s: Save FSCR to init_task.thread.fscr after feature init
  powerpc/64s: Don't let DT CPU features set FSCR_DSCR
  powerpc/64s: Don't init FSCR_DSCR in __init_FSCR()
  powerpc/32s: Fix another build failure with CONFIG_PPC_KUAP_DEBUG
  powerpc/module_64: Use special stub for _mcount() with -mprofile-kernel
  powerpc/module_64: Simplify check for -mprofile-kernel ftrace relocations
  powerpc/module_64: Consolidate ftrace code
  powerpc/32: Disable KASAN with pages bigger than 16k
  powerpc/uaccess: Don't set KUEP by default on book3s/32
  powerpc/uaccess: Don't set KUAP by default on book3s/32
  powerpc/8xx: Reduce time spent in allow_user_access() and friends
  ...
2020-06-05 12:39:30 -07:00
Hanjun Guo
7395683a24 Documentation: cpuidle: update the document
Update the document after the remove of cpuidle_sysfs_switch.

Signed-off-by: Hanjun Guo <guohanjun@huawei.com>
Reviewed-by: Doug Smythies <dsmythies@telus.net>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2020-05-19 17:41:17 +02:00