Merge remote-tracking branch 'linux-pm/linux-next' into sound/upstream-20250520

Author: bardliao

.mailmap

@@ -102,6 +102,7 @@ Ard Biesheuvel <ardb@kernel.org> <ard.biesheuvel@linaro.org>
 Arnaud Patard <arnaud.patard@rtp-net.org>
 Arnd Bergmann <arnd@arndb.de>
 Arun Kumar Neelakantam <quic_aneela@quicinc.com> <aneela@codeaurora.org>
+Asahi Lina <lina+kernel@asahilina.net> <lina@asahilina.net>
 Ashok Raj Nagarajan <quic_arnagara@quicinc.com> <arnagara@codeaurora.org>
 Ashwin Chaugule <quic_ashwinc@quicinc.com> <ashwinc@codeaurora.org>
 Asutosh Das <quic_asutoshd@quicinc.com> <asutoshd@codeaurora.org>

Documentation/ABI/testing/sysfs-devices-system-cpu

@@ -111,6 +111,7 @@ What:		/sys/devices/system/cpu/cpuidle/available_governors
 		/sys/devices/system/cpu/cpuidle/current_driver
 		/sys/devices/system/cpu/cpuidle/current_governor
 		/sys/devices/system/cpu/cpuidle/current_governer_ro
+		/sys/devices/system/cpu/cpuidle/intel_c1_demotion
 Date:		September 2007
 Contact:	Linux kernel mailing list <linux-kernel@vger.kernel.org>
 Description:	Discover cpuidle policy and mechanism
@@ -132,7 +133,11 @@ Description:	Discover cpuidle policy and mechanism
 
 		current_governor_ro: (RO) displays current idle policy.
 
-		See Documentation/admin-guide/pm/cpuidle.rst and
+		intel_c1_demotion: (RW) enables/disables the C1 demotion
+		feature on Intel CPUs.
+
+		See Documentation/admin-guide/pm/cpuidle.rst,
+		Documentation/admin-guide/pm/intel_idle.rst, and
 		Documentation/driver-api/pm/cpuidle.rst for more information.
 
 
@@ -511,6 +516,7 @@ Description:	information about CPUs heterogeneity.
 
 What:		/sys/devices/system/cpu/vulnerabilities
 		/sys/devices/system/cpu/vulnerabilities/gather_data_sampling
+		/sys/devices/system/cpu/vulnerabilities/indirect_target_selection
 		/sys/devices/system/cpu/vulnerabilities/itlb_multihit
 		/sys/devices/system/cpu/vulnerabilities/l1tf
 		/sys/devices/system/cpu/vulnerabilities/mds

Documentation/ABI/testing/sysfs-driver-hid-appletb-kbd

@@ -1,6 +1,6 @@
 What:		/sys/bus/hid/drivers/hid-appletb-kbd/<dev>/mode
-Date:		September, 2023
-KernelVersion:	6.5
+Date:		March, 2025
+KernelVersion:	6.15
 Contact:	linux-input@vger.kernel.org
 Description:
 		The set of keys displayed on the Touch Bar.

Documentation/ABI/testing/sysfs-firmware-acpi

@@ -248,3 +248,24 @@ Description:
 		  # cat ff_pwr_btn
 		  7	enabled
 
+What:		/sys/firmware/acpi/memory_ranges/rangeX
+Date:		February 2025
+Contact:	Tony Luck <tony.luck@intel.com>
+Description:
+		On systems with the ACPI MRRM table reports the parameters for
+		each range.
+
+		base: Starting system physical address.
+
+		length: Length of this range in bytes.
+
+		node: NUMA node that this range belongs to. Negative numbers
+		indicate that the node number could not be determined (e.g
+		for an address range that is reserved for future hot add of
+		memory).
+
+		local_region_id: ID associated with access by agents
+		local to this range of addresses.
+
+		remote_region_id: ID associated with access by agents
+		non-local to this range of addresses.

Documentation/admin-guide/hw-vuln/index.rst

@@ -23,3 +23,4 @@ are configurable at compile, boot or run time.
    gather_data_sampling
    reg-file-data-sampling
    rsb
+   indirect-target-selection

Documentation/admin-guide/hw-vuln/indirect-target-selection.rst

@@ -0,0 +1,168 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+Indirect Target Selection (ITS)
+===============================
+
+ITS is a vulnerability in some Intel CPUs that support Enhanced IBRS and were
+released before Alder Lake. ITS may allow an attacker to control the prediction
+of indirect branches and RETs located in the lower half of a cacheline.
+
+ITS is assigned CVE-2024-28956 with a CVSS score of 4.7 (Medium).
+
+Scope of Impact
+---------------
+- **eIBRS Guest/Host Isolation**: Indirect branches in KVM/kernel may still be
+  predicted with unintended target corresponding to a branch in the guest.
+
+- **Intra-Mode BTI**: In-kernel training such as through cBPF or other native
+  gadgets.
+
+- **Indirect Branch Prediction Barrier (IBPB)**: After an IBPB, indirect
+  branches may still be predicted with targets corresponding to direct branches
+  executed prior to the IBPB. This is fixed by the IPU 2025.1 microcode, which
+  should be available via distro updates. Alternatively microcode can be
+  obtained from Intel's github repository [#f1]_.
+
+Affected CPUs
+-------------
+Below is the list of ITS affected CPUs [#f2]_ [#f3]_:
+
+   ========================  ============  ====================  ===============
+   Common name               Family_Model  eIBRS                 Intra-mode BTI
+                                           Guest/Host Isolation
+   ========================  ============  ====================  ===============
+   SKYLAKE_X (step >= 6)     06_55H        Affected              Affected
+   ICELAKE_X                 06_6AH        Not affected          Affected
+   ICELAKE_D                 06_6CH        Not affected          Affected
+   ICELAKE_L                 06_7EH        Not affected          Affected
+   TIGERLAKE_L               06_8CH        Not affected          Affected
+   TIGERLAKE                 06_8DH        Not affected          Affected
+   KABYLAKE_L (step >= 12)   06_8EH        Affected              Affected
+   KABYLAKE (step >= 13)     06_9EH        Affected              Affected
+   COMETLAKE                 06_A5H        Affected              Affected
+   COMETLAKE_L               06_A6H        Affected              Affected
+   ROCKETLAKE                06_A7H        Not affected          Affected
+   ========================  ============  ====================  ===============
+
+- All affected CPUs enumerate Enhanced IBRS feature.
+- IBPB isolation is affected on all ITS affected CPUs, and need a microcode
+  update for mitigation.
+- None of the affected CPUs enumerate BHI_CTRL which was introduced in Golden
+  Cove (Alder Lake and Sapphire Rapids). This can help guests to determine the
+  host's affected status.
+- Intel Atom CPUs are not affected by ITS.
+
+Mitigation
+----------
+As only the indirect branches and RETs that have their last byte of instruction
+in the lower half of the cacheline are vulnerable to ITS, the basic idea behind
+the mitigation is to not allow indirect branches in the lower half.
+
+This is achieved by relying on existing retpoline support in the kernel, and in
+compilers. ITS-vulnerable retpoline sites are runtime patched to point to newly
+added ITS-safe thunks. These safe thunks consists of indirect branch in the
+second half of the cacheline. Not all retpoline sites are patched to thunks, if
+a retpoline site is evaluated to be ITS-safe, it is replaced with an inline
+indirect branch.
+
+Dynamic thunks
+~~~~~~~~~~~~~~
+From a dynamically allocated pool of safe-thunks, each vulnerable site is
+replaced with a new thunk, such that they get a unique address. This could
+improve the branch prediction accuracy. Also, it is a defense-in-depth measure
+against aliasing.
+
+Note, for simplicity, indirect branches in eBPF programs are always replaced
+with a jump to a static thunk in __x86_indirect_its_thunk_array. If required,
+in future this can be changed to use dynamic thunks.
+
+All vulnerable RETs are replaced with a static thunk, they do not use dynamic
+thunks. This is because RETs get their prediction from RSB mostly that does not
+depend on source address. RETs that underflow RSB may benefit from dynamic
+thunks. But, RETs significantly outnumber indirect branches, and any benefit
+from a unique source address could be outweighed by the increased icache
+footprint and iTLB pressure.
+
+Retpoline
+~~~~~~~~~
+Retpoline sequence also mitigates ITS-unsafe indirect branches. For this
+reason, when retpoline is enabled, ITS mitigation only relocates the RETs to
+safe thunks. Unless user requested the RSB-stuffing mitigation.
+
+RSB Stuffing
+~~~~~~~~~~~~
+RSB-stuffing via Call Depth Tracking is a mitigation for Retbleed RSB-underflow
+attacks. And it also mitigates RETs that are vulnerable to ITS.
+
+Mitigation in guests
+^^^^^^^^^^^^^^^^^^^^
+All guests deploy ITS mitigation by default, irrespective of eIBRS enumeration
+and Family/Model of the guest. This is because eIBRS feature could be hidden
+from a guest. One exception to this is when a guest enumerates BHI_DIS_S, which
+indicates that the guest is running on an unaffected host.
+
+To prevent guests from unnecessarily deploying the mitigation on unaffected
+platforms, Intel has defined ITS_NO bit(62) in MSR IA32_ARCH_CAPABILITIES. When
+a guest sees this bit set, it should not enumerate the ITS bug. Note, this bit
+is not set by any hardware, but is **intended for VMMs to synthesize** it for
+guests as per the host's affected status.
+
+Mitigation options
+^^^^^^^^^^^^^^^^^^
+The ITS mitigation can be controlled using the "indirect_target_selection"
+kernel parameter. The available options are:
+
+   ======== ===================================================================
+   on       (default)  Deploy the "Aligned branch/return thunks" mitigation.
+	    If spectre_v2 mitigation enables retpoline, aligned-thunks are only
+	    deployed for the affected RET instructions. Retpoline mitigates
+	    indirect branches.
+
+   off      Disable ITS mitigation.
+
+   vmexit   Equivalent to "=on" if the CPU is affected by guest/host isolation
+	    part of ITS. Otherwise, mitigation is not deployed. This option is
+	    useful when host userspace is not in the threat model, and only
+	    attacks from guest to host are considered.
+
+   stuff    Deploy RSB-fill mitigation when retpoline is also deployed.
+	    Otherwise, deploy the default mitigation. When retpoline mitigation
+	    is enabled, RSB-stuffing via Call-Depth-Tracking also mitigates
+	    ITS.
+
+   force    Force the ITS bug and deploy the default mitigation.
+   ======== ===================================================================
+
+Sysfs reporting
+---------------
+
+The sysfs file showing ITS mitigation status is:
+
+  /sys/devices/system/cpu/vulnerabilities/indirect_target_selection
+
+Note, microcode mitigation status is not reported in this file.
+
+The possible values in this file are:
+
+.. list-table::
+
+   * - Not affected
+     - The processor is not vulnerable.
+   * - Vulnerable
+     - System is vulnerable and no mitigation has been applied.
+   * - Vulnerable, KVM: Not affected
+     - System is vulnerable to intra-mode BTI, but not affected by eIBRS
+       guest/host isolation.
+   * - Mitigation: Aligned branch/return thunks
+     - The mitigation is enabled, affected indirect branches and RETs are
+       relocated to safe thunks.
+   * - Mitigation: Retpolines, Stuffing RSB
+     - The mitigation is enabled using retpoline and RSB stuffing.
+
+References
+----------
+.. [#f1] Microcode repository - https://github.com/intel/Intel-Linux-Processor-Microcode-Data-Files
+
+.. [#f2] Affected Processors list - https://www.intel.com/content/www/us/en/developer/topic-technology/software-security-guidance/processors-affected-consolidated-product-cpu-model.html
+
+.. [#f3] Affected Processors list (machine readable) - https://github.com/intel/Intel-affected-processor-list

Documentation/admin-guide/kernel-parameters.txt

@@ -1828,6 +1828,13 @@
 				lz4: Select LZ4 compression algorithm to
 				compress/decompress hibernation image.
 
+	hibernate.pm_test_delay=
+			[HIBERNATION]
+			Sets the number of seconds to remain in a hibernation test
+			mode before resuming the system (see
+			/sys/power/pm_test). Only available when CONFIG_PM_DEBUG
+			is set. Default value is 5.
+
 	highmem=nn[KMG]	[KNL,BOOT,EARLY] forces the highmem zone to have an exact
 			size of <nn>. This works even on boxes that have no
 			highmem otherwise. This also works to reduce highmem
@@ -2202,6 +2209,23 @@
 			different crypto accelerators. This option can be used
 			to achieve best performance for particular HW.
 
+	indirect_target_selection= [X86,Intel] Mitigation control for Indirect
+			Target Selection(ITS) bug in Intel CPUs. Updated
+			microcode is also required for a fix in IBPB.
+
+			on:     Enable mitigation (default).
+			off:    Disable mitigation.
+			force:	Force the ITS bug and deploy default
+				mitigation.
+			vmexit: Only deploy mitigation if CPU is affected by
+				guest/host isolation part of ITS.
+			stuff:	Deploy RSB-fill mitigation when retpoline is
+				also deployed. Otherwise, deploy the default
+				mitigation.
+
+			For details see:
+			Documentation/admin-guide/hw-vuln/indirect-target-selection.rst
+
 	init=		[KNL]
 			Format: <full_path>
 			Run specified binary instead of /sbin/init as init
@@ -3693,6 +3717,7 @@
 				expose users to several CPU vulnerabilities.
 				Equivalent to: if nokaslr then kpti=0 [ARM64]
 					       gather_data_sampling=off [X86]
+					       indirect_target_selection=off [X86]
 					       kvm.nx_huge_pages=off [X86]
 					       l1tf=off [X86]
 					       mds=off [X86]

Documentation/admin-guide/pm/intel_idle.rst

@@ -38,6 +38,27 @@ instruction at all.
 only way to pass early-configuration-time parameters to it is via the kernel
 command line.
 
+Sysfs Interface
+===============
+
+The ``intel_idle`` driver exposes the following ``sysfs`` attributes in
+``/sys/devices/system/cpu/cpuidle/``:
+
+``intel_c1_demotion``
+	Enable or disable C1 demotion for all CPUs in the system. This file is
+	only exposed on platforms that support the C1 demotion feature and where
+	it was tested. Value 0 means that C1 demotion is disabled, value 1 means
+	that it is enabled. Write 0 or 1 to disable or enable C1 demotion for
+	all CPUs.
+
+	The C1 demotion feature involves the platform firmware demoting deep
+	C-state requests from the OS (e.g., C6 requests) to C1. The idea is that
+	firmware monitors CPU wake-up rate, and if it is higher than a
+	platform-specific threshold, the firmware demotes deep C-state requests
+	to C1. For example, Linux requests C6, but firmware noticed too many
+	wake-ups per second, and it keeps the CPU in C1. When the CPU stays in
+	C1 long enough, the platform promotes it back to C6. This may improve
+	some workloads' performance, but it may also increase power consumption.
 
 .. _intel-idle-enumeration-of-states: