Merge tag 'rolling-lts/wsl/5.15.123.1' into linux-msft-wsl-5.15.y

Linux rolling-lts/wsl/5.15.123.1

Signed-off-by: Kelsey Steele <[email protected]>

Author: kelsey-steele

Documentation/ABI/testing/configfs-usb-gadget-uvc

@@ -51,7 +51,7 @@ Date:		Dec 2014
 KernelVersion:	4.0
 Description:	Default output terminal descriptors
 
-		All attributes read only:
+		All attributes read only except bSourceID:
 
 		==============	=============================================
 		iTerminal	index of string descriptor

Documentation/ABI/testing/sysfs-kernel-oops_count

@@ -0,0 +1,6 @@
+What:		/sys/kernel/oops_count
+Date:		November 2022
+KernelVersion:	6.2.0
+Contact:	Linux Kernel Hardening List <[email protected]>
+Description:
+		Shows how many times the system has Oopsed since last boot.

Documentation/ABI/testing/sysfs-kernel-warn_count

@@ -0,0 +1,6 @@
+What:		/sys/kernel/warn_count
+Date:		November 2022
+KernelVersion:	6.2.0
+Contact:	Linux Kernel Hardening List <[email protected]>
+Description:
+		Shows how many times the system has Warned since last boot.

Documentation/admin-guide/cgroup-v1/memory.rst

@@ -84,6 +84,8 @@ Brief summary of control files.
  memory.swappiness		     set/show swappiness parameter of vmscan
 				     (See sysctl's vm.swappiness)
  memory.move_charge_at_immigrate     set/show controls of moving charges
+                                     This knob is deprecated and shouldn't be
+                                     used.
  memory.oom_control		     set/show oom controls.
  memory.numa_stat		     show the number of memory usage per numa
 				     node
@@ -723,8 +725,15 @@ NOTE2:
        It is recommended to set the soft limit always below the hard limit,
        otherwise the hard limit will take precedence.
 
-8. Move charges at task migration
-=================================
+8. Move charges at task migration (DEPRECATED!)
+===============================================
+
+THIS IS DEPRECATED!
+
+It's expensive and unreliable! It's better practice to launch workload
+tasks directly from inside their target cgroup. Use dedicated workload
+cgroups to allow fine-grained policy adjustments without having to
+move physical pages between control domains.
 
 Users can move charges associated with a task along with task migration, that
 is, uncharge task's pages from the old cgroup and charge them to the new cgroup.

Documentation/admin-guide/device-mapper/dm-init.rst

@@ -123,3 +123,11 @@ Other examples (per target):
     0 1638400 verity 1 8:1 8:2 4096 4096 204800 1 sha256
     fb1a5a0f00deb908d8b53cb270858975e76cf64105d412ce764225d53b8f3cfd
     51934789604d1b92399c52e7cb149d1b3a1b74bbbcb103b2a0aaacbed5c08584
+
+For setups using device-mapper on top of asynchronously probed block
+devices (MMC, USB, ..), it may be necessary to tell dm-init to
+explicitly wait for them to become available before setting up the
+device-mapper tables. This can be done with the "dm-mod.waitfor="
+module parameter, which takes a list of devices to wait for::
+
+  dm-mod.waitfor=<device1>[,..,<deviceN>]

Documentation/admin-guide/hw-vuln/cross-thread-rsb.rst

@@ -0,0 +1,92 @@
+
+.. SPDX-License-Identifier: GPL-2.0
+
+Cross-Thread Return Address Predictions
+=======================================
+
+Certain AMD and Hygon processors are subject to a cross-thread return address
+predictions vulnerability. When running in SMT mode and one sibling thread
+transitions out of C0 state, the other sibling thread could use return target
+predictions from the sibling thread that transitioned out of C0.
+
+The Spectre v2 mitigations protect the Linux kernel, as it fills the return
+address prediction entries with safe targets when context switching to the idle
+thread. However, KVM does allow a VMM to prevent exiting guest mode when
+transitioning out of C0. This could result in a guest-controlled return target
+being consumed by the sibling thread.
+
+Affected processors
+-------------------
+
+The following CPUs are vulnerable:
+
+    - AMD Family 17h processors
+    - Hygon Family 18h processors
+
+Related CVEs
+------------
+
+The following CVE entry is related to this issue:
+
+   ==============  =======================================
+   CVE-2022-27672  Cross-Thread Return Address Predictions
+   ==============  =======================================
+
+Problem
+-------
+
+Affected SMT-capable processors support 1T and 2T modes of execution when SMT
+is enabled. In 2T mode, both threads in a core are executing code. For the
+processor core to enter 1T mode, it is required that one of the threads
+requests to transition out of the C0 state. This can be communicated with the
+HLT instruction or with an MWAIT instruction that requests non-C0.
+When the thread re-enters the C0 state, the processor transitions back
+to 2T mode, assuming the other thread is also still in C0 state.
+
+In affected processors, the return address predictor (RAP) is partitioned
+depending on the SMT mode. For instance, in 2T mode each thread uses a private
+16-entry RAP, but in 1T mode, the active thread uses a 32-entry RAP. Upon
+transition between 1T/2T mode, the RAP contents are not modified but the RAP
+pointers (which control the next return target to use for predictions) may
+change. This behavior may result in return targets from one SMT thread being
+used by RET predictions in the sibling thread following a 1T/2T switch. In
+particular, a RET instruction executed immediately after a transition to 1T may
+use a return target from the thread that just became idle. In theory, this
+could lead to information disclosure if the return targets used do not come
+from trustworthy code.
+
+Attack scenarios
+----------------
+
+An attack can be mounted on affected processors by performing a series of CALL
+instructions with targeted return locations and then transitioning out of C0
+state.
+
+Mitigation mechanism
+--------------------
+
+Before entering idle state, the kernel context switches to the idle thread. The
+context switch fills the RAP entries (referred to as the RSB in Linux) with safe
+targets by performing a sequence of CALL instructions.
+
+Prevent a guest VM from directly putting the processor into an idle state by
+intercepting HLT and MWAIT instructions.
+
+Both mitigations are required to fully address this issue.
+
+Mitigation control on the kernel command line
+---------------------------------------------
+
+Use existing Spectre v2 mitigations that will fill the RSB on context switch.
+
+Mitigation control for KVM - module parameter
+---------------------------------------------
+
+By default, the KVM hypervisor mitigates this issue by intercepting guest
+attempts to transition out of C0. A VMM can use the KVM_CAP_X86_DISABLE_EXITS
+capability to override those interceptions, but since this is not common, the
+mitigation that covers this path is not enabled by default.
+
+The mitigation for the KVM_CAP_X86_DISABLE_EXITS capability can be turned on
+using the boolean module parameter mitigate_smt_rsb, e.g.:
+        kvm.mitigate_smt_rsb=1

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

@@ -18,3 +18,4 @@ are configurable at compile, boot or run time.
    core-scheduling.rst
    l1d_flush.rst
    processor_mmio_stale_data.rst
+   cross-thread-rsb.rst

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

@@ -479,8 +479,16 @@ Spectre variant 2
    On Intel Skylake-era systems the mitigation covers most, but not all,
    cases. See :ref:`[3] <spec_ref3>` for more details.
 
-   On CPUs with hardware mitigation for Spectre variant 2 (e.g. Enhanced
-   IBRS on x86), retpoline is automatically disabled at run time.
+   On CPUs with hardware mitigation for Spectre variant 2 (e.g. IBRS
+   or enhanced IBRS on x86), retpoline is automatically disabled at run time.
+
+   Systems which support enhanced IBRS (eIBRS) enable IBRS protection once at
+   boot, by setting the IBRS bit, and they're automatically protected against
+   Spectre v2 variant attacks, including cross-thread branch target injections
+   on SMT systems (STIBP). In other words, eIBRS enables STIBP too.
+
+   Legacy IBRS systems clear the IBRS bit on exit to userspace and
+   therefore explicitly enable STIBP for that
 
    The retpoline mitigation is turned on by default on vulnerable
    CPUs. It can be forced on or off by the administrator
@@ -504,9 +512,12 @@ Spectre variant 2
    For Spectre variant 2 mitigation, individual user programs
    can be compiled with return trampolines for indirect branches.
    This protects them from consuming poisoned entries in the branch
-   target buffer left by malicious software.  Alternatively, the
-   programs can disable their indirect branch speculation via prctl()
-   (See :ref:`Documentation/userspace-api/spec_ctrl.rst <set_spec_ctrl>`).
+   target buffer left by malicious software.
+
+   On legacy IBRS systems, at return to userspace, implicit STIBP is disabled
+   because the kernel clears the IBRS bit. In this case, the userspace programs
+   can disable indirect branch speculation via prctl() (See
+   :ref:`Documentation/userspace-api/spec_ctrl.rst <set_spec_ctrl>`).
    On x86, this will turn on STIBP to guard against attacks from the
    sibling thread when the user program is running, and use IBPB to
    flush the branch target buffer when switching to/from the program.

Documentation/admin-guide/kdump/gdbmacros.txt

@@ -312,10 +312,10 @@ define dmesg
 			set var $prev_flags = $info->flags
 		end
 
-		set var $id = ($id + 1) & $id_mask
 		if ($id == $end_id)
 			loop_break
 		end
+		set var $id = ($id + 1) & $id_mask
 	end
 end
 document dmesg

Documentation/admin-guide/kernel-parameters.txt

@@ -916,10 +916,6 @@
 
 	debugpat	[X86] Enable PAT debugging
 
-	decnet.addr=	[HW,NET]
-			Format: <area>[,<node>]
-			See also Documentation/networking/decnet.rst.
-
 	default_hugepagesz=
 			[HW] The size of the default HugeTLB page. This is
 			the size represented by the legacy /proc/ hugepages
@@ -2200,24 +2196,57 @@
 
 	ivrs_ioapic	[HW,X86-64]
 			Provide an override to the IOAPIC-ID<->DEVICE-ID
-			mapping provided in the IVRS ACPI table. For
-			example, to map IOAPIC-ID decimal 10 to
-			PCI device 00:14.0 write the parameter as:
+			mapping provided in the IVRS ACPI table.
+			By default, PCI segment is 0, and can be omitted.
+
+			For example, to map IOAPIC-ID decimal 10 to
+			PCI segment 0x1 and PCI device 00:14.0,
+			write the parameter as:
+				ivrs_ioapic=10@0001:00:14.0
+
+			Deprecated formats:
+			* To map IOAPIC-ID decimal 10 to PCI device 00:14.0
+			  write the parameter as:
 				ivrs_ioapic[10]=00:14.0
+			* To map IOAPIC-ID decimal 10 to PCI segment 0x1 and
+			  PCI device 00:14.0 write the parameter as:
+				ivrs_ioapic[10]=0001:00:14.0
 
 	ivrs_hpet	[HW,X86-64]
 			Provide an override to the HPET-ID<->DEVICE-ID
-			mapping provided in the IVRS ACPI table. For
-			example, to map HPET-ID decimal 0 to
-			PCI device 00:14.0 write the parameter as:
+			mapping provided in the IVRS ACPI table.
+			By default, PCI segment is 0, and can be omitted.
+
+			For example, to map HPET-ID decimal 10 to
+			PCI segment 0x1 and PCI device 00:14.0,
+			write the parameter as:
+				ivrs_hpet=10@0001:00:14.0
+
+			Deprecated formats:
+			* To map HPET-ID decimal 0 to PCI device 00:14.0
+			  write the parameter as:
 				ivrs_hpet[0]=00:14.0
+			* To map HPET-ID decimal 10 to PCI segment 0x1 and
+			  PCI device 00:14.0 write the parameter as:
+				ivrs_ioapic[10]=0001:00:14.0
 
 	ivrs_acpihid	[HW,X86-64]
 			Provide an override to the ACPI-HID:UID<->DEVICE-ID
-			mapping provided in the IVRS ACPI table. For
-			example, to map UART-HID:UID AMD0020:0 to
-			PCI device 00:14.5 write the parameter as:
+			mapping provided in the IVRS ACPI table.
+			By default, PCI segment is 0, and can be omitted.
+
+			For example, to map UART-HID:UID AMD0020:0 to
+			PCI segment 0x1 and PCI device ID 00:14.5,
+			write the parameter as:
+				ivrs_acpihid=AMD0020:0@0001:00:14.5
+
+			Deprecated formats:
+			* To map UART-HID:UID AMD0020:0 to PCI segment is 0,
+			  PCI device ID 00:14.5, write the parameter as:
 				ivrs_acpihid[00:14.5]=AMD0020:0
+			* To map UART-HID:UID AMD0020:0 to PCI segment 0x1 and
+			  PCI device ID 00:14.5, write the parameter as:
+				ivrs_acpihid[0001:00:14.5]=AMD0020:0
 
 	js=		[HW,JOY] Analog joystick
 			See Documentation/input/joydev/joystick.rst.