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-rw-r--r--Documentation/ABI/testing/sysfs-class-devfreq3
-rw-r--r--Documentation/ABI/testing/sysfs-class-net-queues22
-rw-r--r--Documentation/ABI/testing/sysfs-class-net-statistics48
-rw-r--r--Documentation/ABI/testing/sysfs-devices-system-cpu1
-rw-r--r--Documentation/admin-guide/hw-vuln/index.rst1
-rw-r--r--Documentation/admin-guide/hw-vuln/reg-file-data-sampling.rst104
-rw-r--r--Documentation/admin-guide/hw-vuln/spectre.rst18
-rw-r--r--Documentation/admin-guide/kernel-parameters.txt27
-rw-r--r--Documentation/block/queue-sysfs.rst7
-rw-r--r--Documentation/filesystems/directory-locking.rst29
-rw-r--r--Documentation/filesystems/locking.rst5
-rw-r--r--Documentation/filesystems/porting.rst18
-rw-r--r--Documentation/sound/soc/dapm.rst2
-rw-r--r--Documentation/x86/mds.rst38
14 files changed, 251 insertions, 72 deletions
diff --git a/Documentation/ABI/testing/sysfs-class-devfreq b/Documentation/ABI/testing/sysfs-class-devfreq
index b8ebff4b1..4514cf9fc 100644
--- a/Documentation/ABI/testing/sysfs-class-devfreq
+++ b/Documentation/ABI/testing/sysfs-class-devfreq
@@ -66,6 +66,9 @@ Description:
echo 0 > /sys/class/devfreq/.../trans_stat
+ If the transition table is bigger than PAGE_SIZE, reading
+ this will return an -EFBIG error.
+
What: /sys/class/devfreq/.../userspace/set_freq
Date: September 2011
Contact: MyungJoo Ham <myungjoo.ham@samsung.com>
diff --git a/Documentation/ABI/testing/sysfs-class-net-queues b/Documentation/ABI/testing/sysfs-class-net-queues
index 978b76358..40d5aab84 100644
--- a/Documentation/ABI/testing/sysfs-class-net-queues
+++ b/Documentation/ABI/testing/sysfs-class-net-queues
@@ -1,4 +1,4 @@
-What: /sys/class/<iface>/queues/rx-<queue>/rps_cpus
+What: /sys/class/net/<iface>/queues/rx-<queue>/rps_cpus
Date: March 2010
KernelVersion: 2.6.35
Contact: netdev@vger.kernel.org
@@ -8,7 +8,7 @@ Description:
network device queue. Possible values depend on the number
of available CPU(s) in the system.
-What: /sys/class/<iface>/queues/rx-<queue>/rps_flow_cnt
+What: /sys/class/net/<iface>/queues/rx-<queue>/rps_flow_cnt
Date: April 2010
KernelVersion: 2.6.35
Contact: netdev@vger.kernel.org
@@ -16,7 +16,7 @@ Description:
Number of Receive Packet Steering flows being currently
processed by this particular network device receive queue.
-What: /sys/class/<iface>/queues/tx-<queue>/tx_timeout
+What: /sys/class/net/<iface>/queues/tx-<queue>/tx_timeout
Date: November 2011
KernelVersion: 3.3
Contact: netdev@vger.kernel.org
@@ -24,7 +24,7 @@ Description:
Indicates the number of transmit timeout events seen by this
network interface transmit queue.
-What: /sys/class/<iface>/queues/tx-<queue>/tx_maxrate
+What: /sys/class/net/<iface>/queues/tx-<queue>/tx_maxrate
Date: March 2015
KernelVersion: 4.1
Contact: netdev@vger.kernel.org
@@ -32,7 +32,7 @@ Description:
A Mbps max-rate set for the queue, a value of zero means disabled,
default is disabled.
-What: /sys/class/<iface>/queues/tx-<queue>/xps_cpus
+What: /sys/class/net/<iface>/queues/tx-<queue>/xps_cpus
Date: November 2010
KernelVersion: 2.6.38
Contact: netdev@vger.kernel.org
@@ -42,7 +42,7 @@ Description:
network device transmit queue. Possible vaules depend on the
number of available CPU(s) in the system.
-What: /sys/class/<iface>/queues/tx-<queue>/xps_rxqs
+What: /sys/class/net/<iface>/queues/tx-<queue>/xps_rxqs
Date: June 2018
KernelVersion: 4.18.0
Contact: netdev@vger.kernel.org
@@ -53,7 +53,7 @@ Description:
number of available receive queue(s) in the network device.
Default is disabled.
-What: /sys/class/<iface>/queues/tx-<queue>/byte_queue_limits/hold_time
+What: /sys/class/net/<iface>/queues/tx-<queue>/byte_queue_limits/hold_time
Date: November 2011
KernelVersion: 3.3
Contact: netdev@vger.kernel.org
@@ -62,7 +62,7 @@ Description:
of this particular network device transmit queue.
Default value is 1000.
-What: /sys/class/<iface>/queues/tx-<queue>/byte_queue_limits/inflight
+What: /sys/class/net/<iface>/queues/tx-<queue>/byte_queue_limits/inflight
Date: November 2011
KernelVersion: 3.3
Contact: netdev@vger.kernel.org
@@ -70,7 +70,7 @@ Description:
Indicates the number of bytes (objects) in flight on this
network device transmit queue.
-What: /sys/class/<iface>/queues/tx-<queue>/byte_queue_limits/limit
+What: /sys/class/net/<iface>/queues/tx-<queue>/byte_queue_limits/limit
Date: November 2011
KernelVersion: 3.3
Contact: netdev@vger.kernel.org
@@ -79,7 +79,7 @@ Description:
on this network device transmit queue. This value is clamped
to be within the bounds defined by limit_max and limit_min.
-What: /sys/class/<iface>/queues/tx-<queue>/byte_queue_limits/limit_max
+What: /sys/class/net/<iface>/queues/tx-<queue>/byte_queue_limits/limit_max
Date: November 2011
KernelVersion: 3.3
Contact: netdev@vger.kernel.org
@@ -88,7 +88,7 @@ Description:
queued on this network device transmit queue. See
include/linux/dynamic_queue_limits.h for the default value.
-What: /sys/class/<iface>/queues/tx-<queue>/byte_queue_limits/limit_min
+What: /sys/class/net/<iface>/queues/tx-<queue>/byte_queue_limits/limit_min
Date: November 2011
KernelVersion: 3.3
Contact: netdev@vger.kernel.org
diff --git a/Documentation/ABI/testing/sysfs-class-net-statistics b/Documentation/ABI/testing/sysfs-class-net-statistics
index 55db27815..53e508c69 100644
--- a/Documentation/ABI/testing/sysfs-class-net-statistics
+++ b/Documentation/ABI/testing/sysfs-class-net-statistics
@@ -1,4 +1,4 @@
-What: /sys/class/<iface>/statistics/collisions
+What: /sys/class/net/<iface>/statistics/collisions
Date: April 2005
KernelVersion: 2.6.12
Contact: netdev@vger.kernel.org
@@ -6,7 +6,7 @@ Description:
Indicates the number of collisions seen by this network device.
This value might not be relevant with all MAC layers.
-What: /sys/class/<iface>/statistics/multicast
+What: /sys/class/net/<iface>/statistics/multicast
Date: April 2005
KernelVersion: 2.6.12
Contact: netdev@vger.kernel.org
@@ -14,7 +14,7 @@ Description:
Indicates the number of multicast packets received by this
network device.
-What: /sys/class/<iface>/statistics/rx_bytes
+What: /sys/class/net/<iface>/statistics/rx_bytes
Date: April 2005
KernelVersion: 2.6.12
Contact: netdev@vger.kernel.org
@@ -23,7 +23,7 @@ Description:
See the network driver for the exact meaning of when this
value is incremented.
-What: /sys/class/<iface>/statistics/rx_compressed
+What: /sys/class/net/<iface>/statistics/rx_compressed
Date: April 2005
KernelVersion: 2.6.12
Contact: netdev@vger.kernel.org
@@ -32,7 +32,7 @@ Description:
network device. This value might only be relevant for interfaces
that support packet compression (e.g: PPP).
-What: /sys/class/<iface>/statistics/rx_crc_errors
+What: /sys/class/net/<iface>/statistics/rx_crc_errors
Date: April 2005
KernelVersion: 2.6.12
Contact: netdev@vger.kernel.org
@@ -41,7 +41,7 @@ Description:
by this network device. Note that the specific meaning might
depend on the MAC layer used by the interface.
-What: /sys/class/<iface>/statistics/rx_dropped
+What: /sys/class/net/<iface>/statistics/rx_dropped
Date: April 2005
KernelVersion: 2.6.12
Contact: netdev@vger.kernel.org
@@ -51,7 +51,7 @@ Description:
packet processing. See the network driver for the exact
meaning of this value.
-What: /sys/class/<iface>/statistics/rx_errors
+What: /sys/class/net/<iface>/statistics/rx_errors
Date: April 2005
KernelVersion: 2.6.12
Contact: netdev@vger.kernel.org
@@ -59,7 +59,7 @@ Description:
Indicates the number of receive errors on this network device.
See the network driver for the exact meaning of this value.
-What: /sys/class/<iface>/statistics/rx_fifo_errors
+What: /sys/class/net/<iface>/statistics/rx_fifo_errors
Date: April 2005
KernelVersion: 2.6.12
Contact: netdev@vger.kernel.org
@@ -68,7 +68,7 @@ Description:
network device. See the network driver for the exact
meaning of this value.
-What: /sys/class/<iface>/statistics/rx_frame_errors
+What: /sys/class/net/<iface>/statistics/rx_frame_errors
Date: April 2005
KernelVersion: 2.6.12
Contact: netdev@vger.kernel.org
@@ -78,7 +78,7 @@ Description:
on the MAC layer protocol used. See the network driver for
the exact meaning of this value.
-What: /sys/class/<iface>/statistics/rx_length_errors
+What: /sys/class/net/<iface>/statistics/rx_length_errors
Date: April 2005
KernelVersion: 2.6.12
Contact: netdev@vger.kernel.org
@@ -87,7 +87,7 @@ Description:
error, oversized or undersized. See the network driver for the
exact meaning of this value.
-What: /sys/class/<iface>/statistics/rx_missed_errors
+What: /sys/class/net/<iface>/statistics/rx_missed_errors
Date: April 2005
KernelVersion: 2.6.12
Contact: netdev@vger.kernel.org
@@ -96,7 +96,7 @@ Description:
due to lack of capacity in the receive side. See the network
driver for the exact meaning of this value.
-What: /sys/class/<iface>/statistics/rx_nohandler
+What: /sys/class/net/<iface>/statistics/rx_nohandler
Date: February 2016
KernelVersion: 4.6
Contact: netdev@vger.kernel.org
@@ -104,7 +104,7 @@ Description:
Indicates the number of received packets that were dropped on
an inactive device by the network core.
-What: /sys/class/<iface>/statistics/rx_over_errors
+What: /sys/class/net/<iface>/statistics/rx_over_errors
Date: April 2005
KernelVersion: 2.6.12
Contact: netdev@vger.kernel.org
@@ -114,7 +114,7 @@ Description:
(e.g: larger than MTU). See the network driver for the exact
meaning of this value.
-What: /sys/class/<iface>/statistics/rx_packets
+What: /sys/class/net/<iface>/statistics/rx_packets
Date: April 2005
KernelVersion: 2.6.12
Contact: netdev@vger.kernel.org
@@ -122,7 +122,7 @@ Description:
Indicates the total number of good packets received by this
network device.
-What: /sys/class/<iface>/statistics/tx_aborted_errors
+What: /sys/class/net/<iface>/statistics/tx_aborted_errors
Date: April 2005
KernelVersion: 2.6.12
Contact: netdev@vger.kernel.org
@@ -132,7 +132,7 @@ Description:
a medium collision). See the network driver for the exact
meaning of this value.
-What: /sys/class/<iface>/statistics/tx_bytes
+What: /sys/class/net/<iface>/statistics/tx_bytes
Date: April 2005
KernelVersion: 2.6.12
Contact: netdev@vger.kernel.org
@@ -143,7 +143,7 @@ Description:
transmitted packets or all packets that have been queued for
transmission.
-What: /sys/class/<iface>/statistics/tx_carrier_errors
+What: /sys/class/net/<iface>/statistics/tx_carrier_errors
Date: April 2005
KernelVersion: 2.6.12
Contact: netdev@vger.kernel.org
@@ -152,7 +152,7 @@ Description:
because of carrier errors (e.g: physical link down). See the
network driver for the exact meaning of this value.
-What: /sys/class/<iface>/statistics/tx_compressed
+What: /sys/class/net/<iface>/statistics/tx_compressed
Date: April 2005
KernelVersion: 2.6.12
Contact: netdev@vger.kernel.org
@@ -161,7 +161,7 @@ Description:
this might only be relevant for devices that support
compression (e.g: PPP).
-What: /sys/class/<iface>/statistics/tx_dropped
+What: /sys/class/net/<iface>/statistics/tx_dropped
Date: April 2005
KernelVersion: 2.6.12
Contact: netdev@vger.kernel.org
@@ -170,7 +170,7 @@ Description:
See the driver for the exact reasons as to why the packets were
dropped.
-What: /sys/class/<iface>/statistics/tx_errors
+What: /sys/class/net/<iface>/statistics/tx_errors
Date: April 2005
KernelVersion: 2.6.12
Contact: netdev@vger.kernel.org
@@ -179,7 +179,7 @@ Description:
a network device. See the driver for the exact reasons as to
why the packets were dropped.
-What: /sys/class/<iface>/statistics/tx_fifo_errors
+What: /sys/class/net/<iface>/statistics/tx_fifo_errors
Date: April 2005
KernelVersion: 2.6.12
Contact: netdev@vger.kernel.org
@@ -188,7 +188,7 @@ Description:
FIFO error. See the driver for the exact reasons as to why the
packets were dropped.
-What: /sys/class/<iface>/statistics/tx_heartbeat_errors
+What: /sys/class/net/<iface>/statistics/tx_heartbeat_errors
Date: April 2005
KernelVersion: 2.6.12
Contact: netdev@vger.kernel.org
@@ -197,7 +197,7 @@ Description:
reported as heartbeat errors. See the driver for the exact
reasons as to why the packets were dropped.
-What: /sys/class/<iface>/statistics/tx_packets
+What: /sys/class/net/<iface>/statistics/tx_packets
Date: April 2005
KernelVersion: 2.6.12
Contact: netdev@vger.kernel.org
@@ -206,7 +206,7 @@ Description:
device. See the driver for whether this reports the number of all
attempted or successful transmissions.
-What: /sys/class/<iface>/statistics/tx_window_errors
+What: /sys/class/net/<iface>/statistics/tx_window_errors
Date: April 2005
KernelVersion: 2.6.12
Contact: netdev@vger.kernel.org
diff --git a/Documentation/ABI/testing/sysfs-devices-system-cpu b/Documentation/ABI/testing/sysfs-devices-system-cpu
index bfb4f4fad..2a273bfeb 100644
--- a/Documentation/ABI/testing/sysfs-devices-system-cpu
+++ b/Documentation/ABI/testing/sysfs-devices-system-cpu
@@ -507,6 +507,7 @@ What: /sys/devices/system/cpu/vulnerabilities
/sys/devices/system/cpu/vulnerabilities/mds
/sys/devices/system/cpu/vulnerabilities/meltdown
/sys/devices/system/cpu/vulnerabilities/mmio_stale_data
+ /sys/devices/system/cpu/vulnerabilities/reg_file_data_sampling
/sys/devices/system/cpu/vulnerabilities/retbleed
/sys/devices/system/cpu/vulnerabilities/spec_store_bypass
/sys/devices/system/cpu/vulnerabilities/spectre_v1
diff --git a/Documentation/admin-guide/hw-vuln/index.rst b/Documentation/admin-guide/hw-vuln/index.rst
index 84742be22..e020d1637 100644
--- a/Documentation/admin-guide/hw-vuln/index.rst
+++ b/Documentation/admin-guide/hw-vuln/index.rst
@@ -18,3 +18,4 @@ are configurable at compile, boot or run time.
processor_mmio_stale_data.rst
gather_data_sampling.rst
srso
+ reg-file-data-sampling
diff --git a/Documentation/admin-guide/hw-vuln/reg-file-data-sampling.rst b/Documentation/admin-guide/hw-vuln/reg-file-data-sampling.rst
new file mode 100644
index 000000000..810424b4b
--- /dev/null
+++ b/Documentation/admin-guide/hw-vuln/reg-file-data-sampling.rst
@@ -0,0 +1,104 @@
+==================================
+Register File Data Sampling (RFDS)
+==================================
+
+Register File Data Sampling (RFDS) is a microarchitectural vulnerability that
+only affects Intel Atom parts(also branded as E-cores). RFDS may allow
+a malicious actor to infer data values previously used in floating point
+registers, vector registers, or integer registers. RFDS does not provide the
+ability to choose which data is inferred. CVE-2023-28746 is assigned to RFDS.
+
+Affected Processors
+===================
+Below is the list of affected Intel processors [#f1]_:
+
+ =================== ============
+ Common name Family_Model
+ =================== ============
+ ATOM_GOLDMONT 06_5CH
+ ATOM_GOLDMONT_D 06_5FH
+ ATOM_GOLDMONT_PLUS 06_7AH
+ ATOM_TREMONT_D 06_86H
+ ATOM_TREMONT 06_96H
+ ALDERLAKE 06_97H
+ ALDERLAKE_L 06_9AH
+ ATOM_TREMONT_L 06_9CH
+ RAPTORLAKE 06_B7H
+ RAPTORLAKE_P 06_BAH
+ ALDERLAKE_N 06_BEH
+ RAPTORLAKE_S 06_BFH
+ =================== ============
+
+As an exception to this table, Intel Xeon E family parts ALDERLAKE(06_97H) and
+RAPTORLAKE(06_B7H) codenamed Catlow are not affected. They are reported as
+vulnerable in Linux because they share the same family/model with an affected
+part. Unlike their affected counterparts, they do not enumerate RFDS_CLEAR or
+CPUID.HYBRID. This information could be used to distinguish between the
+affected and unaffected parts, but it is deemed not worth adding complexity as
+the reporting is fixed automatically when these parts enumerate RFDS_NO.
+
+Mitigation
+==========
+Intel released a microcode update that enables software to clear sensitive
+information using the VERW instruction. Like MDS, RFDS deploys the same
+mitigation strategy to force the CPU to clear the affected buffers before an
+attacker can extract the secrets. This is achieved by using the otherwise
+unused and obsolete VERW instruction in combination with a microcode update.
+The microcode clears the affected CPU buffers when the VERW instruction is
+executed.
+
+Mitigation points
+-----------------
+VERW is executed by the kernel before returning to user space, and by KVM
+before VMentry. None of the affected cores support SMT, so VERW is not required
+at C-state transitions.
+
+New bits in IA32_ARCH_CAPABILITIES
+----------------------------------
+Newer processors and microcode update on existing affected processors added new
+bits to IA32_ARCH_CAPABILITIES MSR. These bits can be used to enumerate
+vulnerability and mitigation capability:
+
+- Bit 27 - RFDS_NO - When set, processor is not affected by RFDS.
+- Bit 28 - RFDS_CLEAR - When set, processor is affected by RFDS, and has the
+ microcode that clears the affected buffers on VERW execution.
+
+Mitigation control on the kernel command line
+---------------------------------------------
+The kernel command line allows to control RFDS mitigation at boot time with the
+parameter "reg_file_data_sampling=". The valid arguments are:
+
+ ========== =================================================================
+ on If the CPU is vulnerable, enable mitigation; CPU buffer clearing
+ on exit to userspace and before entering a VM.
+ off Disables mitigation.
+ ========== =================================================================
+
+Mitigation default is selected by CONFIG_MITIGATION_RFDS.
+
+Mitigation status information
+-----------------------------
+The Linux kernel provides a sysfs interface to enumerate the current
+vulnerability status of the system: whether the system is vulnerable, and
+which mitigations are active. The relevant sysfs file is:
+
+ /sys/devices/system/cpu/vulnerabilities/reg_file_data_sampling
+
+The possible values in this file are:
+
+ .. list-table::
+
+ * - 'Not affected'
+ - The processor is not vulnerable
+ * - 'Vulnerable'
+ - The processor is vulnerable, but no mitigation enabled
+ * - 'Vulnerable: No microcode'
+ - The processor is vulnerable but microcode is not updated.
+ * - 'Mitigation: Clear Register File'
+ - The processor is vulnerable and the CPU buffer clearing mitigation is
+ enabled.
+
+References
+----------
+.. [#f1] Affected Processors
+ https://www.intel.com/content/www/us/en/developer/topic-technology/software-security-guidance/processors-affected-consolidated-product-cpu-model.html
diff --git a/Documentation/admin-guide/hw-vuln/spectre.rst b/Documentation/admin-guide/hw-vuln/spectre.rst
index 0fba3758d..305600351 100644
--- a/Documentation/admin-guide/hw-vuln/spectre.rst
+++ b/Documentation/admin-guide/hw-vuln/spectre.rst
@@ -484,11 +484,14 @@ Spectre variant 2
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.
+ Spectre v2 variant attacks.
- Legacy IBRS systems clear the IBRS bit on exit to userspace and
- therefore explicitly enable STIBP for that
+ On Intel's enhanced IBRS systems, this includes cross-thread branch target
+ injections on SMT systems (STIBP). In other words, Intel eIBRS enables
+ STIBP, too.
+
+ AMD Automatic IBRS does not protect userspace, and Legacy IBRS systems clear
+ the IBRS bit on exit to userspace, therefore both explicitly enable STIBP.
The retpoline mitigation is turned on by default on vulnerable
CPUs. It can be forced on or off by the administrator
@@ -622,9 +625,10 @@ kernel command line.
retpoline,generic Retpolines
retpoline,lfence LFENCE; indirect branch
retpoline,amd alias for retpoline,lfence
- eibrs enhanced IBRS
- eibrs,retpoline enhanced IBRS + Retpolines
- eibrs,lfence enhanced IBRS + LFENCE
+ eibrs Enhanced/Auto IBRS
+ eibrs,retpoline Enhanced/Auto IBRS + Retpolines
+ eibrs,lfence Enhanced/Auto IBRS + LFENCE
+ ibrs use IBRS to protect kernel
Not specifying this option is equivalent to
spectre_v2=auto.
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index f1f7c068c..8e4882bb8 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -993,6 +993,26 @@
The filter can be disabled or changed to another
driver later using sysfs.
+ reg_file_data_sampling=
+ [X86] Controls mitigation for Register File Data
+ Sampling (RFDS) vulnerability. RFDS is a CPU
+ vulnerability which may allow userspace to infer
+ kernel data values previously stored in floating point
+ registers, vector registers, or integer registers.
+ RFDS only affects Intel Atom processors.
+
+ on: Turns ON the mitigation.
+ off: Turns OFF the mitigation.
+
+ This parameter overrides the compile time default set
+ by CONFIG_MITIGATION_RFDS. Mitigation cannot be
+ disabled when other VERW based mitigations (like MDS)
+ are enabled. In order to disable RFDS mitigation all
+ VERW based mitigations need to be disabled.
+
+ For details see:
+ Documentation/admin-guide/hw-vuln/reg-file-data-sampling.rst
+
driver_async_probe= [KNL]
List of driver names to be probed asynchronously.
Format: <driver_name1>,<driver_name2>...
@@ -2919,6 +2939,7 @@
nopti [X86,PPC]
nospectre_v1 [X86,PPC]
nospectre_v2 [X86,PPC,S390,ARM64]
+ reg_file_data_sampling=off [X86]
retbleed=off [X86]
spec_store_bypass_disable=off [X86,PPC]
spectre_v2_user=off [X86]
@@ -5091,9 +5112,9 @@
retpoline,generic - Retpolines
retpoline,lfence - LFENCE; indirect branch
retpoline,amd - alias for retpoline,lfence
- eibrs - enhanced IBRS
- eibrs,retpoline - enhanced IBRS + Retpolines
- eibrs,lfence - enhanced IBRS + LFENCE
+ eibrs - Enhanced/Auto IBRS
+ eibrs,retpoline - Enhanced/Auto IBRS + Retpolines
+ eibrs,lfence - Enhanced/Auto IBRS + LFENCE
ibrs - use IBRS to protect kernel
Not specifying this option is equivalent to
diff --git a/Documentation/block/queue-sysfs.rst b/Documentation/block/queue-sysfs.rst
index 2638d3446..c8bf8bc3c 100644
--- a/Documentation/block/queue-sysfs.rst
+++ b/Documentation/block/queue-sysfs.rst
@@ -273,4 +273,11 @@ devices are described in the ZBC (Zoned Block Commands) and ZAC
do not support zone commands, they will be treated as regular block devices
and zoned will report "none".
+zone_write_granularity (RO)
+---------------------------
+This indicates the alignment constraint, in bytes, for write operations in
+sequential zones of zoned block devices (devices with a zoned attributed
+that reports "host-managed" or "host-aware"). This value is always 0 for
+regular block devices.
+
Jens Axboe <jens.axboe@oracle.com>, February 2009
diff --git a/Documentation/filesystems/directory-locking.rst b/Documentation/filesystems/directory-locking.rst
index dccd61c7c..193c22687 100644
--- a/Documentation/filesystems/directory-locking.rst
+++ b/Documentation/filesystems/directory-locking.rst
@@ -22,13 +22,16 @@ exclusive.
3) object removal. Locking rules: caller locks parent, finds victim,
locks victim and calls the method. Locks are exclusive.
-4) rename() that is _not_ cross-directory. Locking rules: caller locks the
-parent and finds source and target. We lock both (provided they exist). If we
-need to lock two inodes of different type (dir vs non-dir), we lock directory
-first. If we need to lock two inodes of the same type, lock them in inode
-pointer order. Then call the method. All locks are exclusive.
-NB: we might get away with locking the source (and target in exchange
-case) shared.
+4) rename() that is _not_ cross-directory. Locking rules: caller locks
+the parent and finds source and target. Then we decide which of the
+source and target need to be locked. Source needs to be locked if it's a
+non-directory; target - if it's a non-directory or about to be removed.
+Take the locks that need to be taken, in inode pointer order if need
+to take both (that can happen only when both source and target are
+non-directories - the source because it wouldn't be locked otherwise
+and the target because mixing directory and non-directory is allowed
+only with RENAME_EXCHANGE, and that won't be removing the target).
+After the locks had been taken, call the method. All locks are exclusive.
5) link creation. Locking rules:
@@ -44,20 +47,17 @@ rules:
* lock the filesystem
* lock parents in "ancestors first" order. If one is not ancestor of
- the other, lock them in inode pointer order.
+ the other, lock the parent of source first.
* find source and target.
* if old parent is equal to or is a descendent of target
fail with -ENOTEMPTY
* if new parent is equal to or is a descendent of source
fail with -ELOOP
- * Lock both the source and the target provided they exist. If we
- need to lock two inodes of different type (dir vs non-dir), we lock
- the directory first. If we need to lock two inodes of the same type,
- lock them in inode pointer order.
+ * Lock subdirectories involved (source before target).
+ * Lock non-directories involved, in inode pointer order.
* call the method.
-All ->i_rwsem are taken exclusive. Again, we might get away with locking
-the source (and target in exchange case) shared.
+All ->i_rwsem are taken exclusive.
The rules above obviously guarantee that all directories that are going to be
read, modified or removed by method will be locked by caller.
@@ -67,6 +67,7 @@ If no directory is its own ancestor, the scheme above is deadlock-free.
Proof:
+[XXX: will be updated once we are done massaging the lock_rename()]
First of all, at any moment we have a linear ordering of the
objects - A < B iff (A is an ancestor of B) or (B is not an ancestor
of A and ptr(A) < ptr(B)).
diff --git a/Documentation/filesystems/locking.rst b/Documentation/filesystems/locking.rst
index c0f2c7586..fbd695d66 100644
--- a/Documentation/filesystems/locking.rst
+++ b/Documentation/filesystems/locking.rst
@@ -95,7 +95,7 @@ symlink: exclusive
mkdir: exclusive
unlink: exclusive (both)
rmdir: exclusive (both)(see below)
-rename: exclusive (all) (see below)
+rename: exclusive (both parents, some children) (see below)
readlink: no
get_link: no
setattr: exclusive
@@ -113,6 +113,9 @@ tmpfile: no
Additionally, ->rmdir(), ->unlink() and ->rename() have ->i_rwsem
exclusive on victim.
cross-directory ->rename() has (per-superblock) ->s_vfs_rename_sem.
+ ->unlink() and ->rename() have ->i_rwsem exclusive on all non-directories
+ involved.
+ ->rename() has ->i_rwsem exclusive on any subdirectory that changes parent.
See Documentation/filesystems/directory-locking.rst for more detailed discussion
of the locking scheme for directory operations.
diff --git a/Documentation/filesystems/porting.rst b/Documentation/filesystems/porting.rst
index 867036aa9..0a2d29d84 100644
--- a/Documentation/filesystems/porting.rst
+++ b/Documentation/filesystems/porting.rst
@@ -865,3 +865,21 @@ no matter what. Everything is handled by the caller.
clone_private_mount() returns a longterm mount now, so the proper destructor of
its result is kern_unmount() or kern_unmount_array().
+
+---
+
+**mandatory**
+
+If ->rename() update of .. on cross-directory move needs an exclusion with
+directory modifications, do *not* lock the subdirectory in question in your
+->rename() - it's done by the caller now [that item should've been added in
+28eceeda130f "fs: Lock moved directories"].
+
+---
+
+**mandatory**
+
+On same-directory ->rename() the (tautological) update of .. is not protected
+by any locks; just don't do it if the old parent is the same as the new one.
+We really can't lock two subdirectories in same-directory rename - not without
+deadlocks.
diff --git a/Documentation/sound/soc/dapm.rst b/Documentation/sound/soc/dapm.rst
index 8e4410793..c3154ce6e 100644
--- a/Documentation/sound/soc/dapm.rst
+++ b/Documentation/sound/soc/dapm.rst
@@ -234,7 +234,7 @@ corresponding soft power control. In this case it is necessary to create
a virtual widget - a widget with no control bits e.g.
::
- SND_SOC_DAPM_MIXER("AC97 Mixer", SND_SOC_DAPM_NOPM, 0, 0, NULL, 0),
+ SND_SOC_DAPM_MIXER("AC97 Mixer", SND_SOC_NOPM, 0, 0, NULL, 0),
This can be used to merge to signal paths together in software.
diff --git a/Documentation/x86/mds.rst b/Documentation/x86/mds.rst
index 5d4330be2..e801df0bb 100644
--- a/Documentation/x86/mds.rst
+++ b/Documentation/x86/mds.rst
@@ -95,6 +95,9 @@ The kernel provides a function to invoke the buffer clearing:
mds_clear_cpu_buffers()
+Also macro CLEAR_CPU_BUFFERS can be used in ASM late in exit-to-user path.
+Other than CFLAGS.ZF, this macro doesn't clobber any registers.
+
The mitigation is invoked on kernel/userspace, hypervisor/guest and C-state
(idle) transitions.
@@ -138,17 +141,30 @@ Mitigation points
When transitioning from kernel to user space the CPU buffers are flushed
on affected CPUs when the mitigation is not disabled on the kernel
- command line. The migitation is enabled through the static key
- mds_user_clear.
-
- The mitigation is invoked in prepare_exit_to_usermode() which covers
- all but one of the kernel to user space transitions. The exception
- is when we return from a Non Maskable Interrupt (NMI), which is
- handled directly in do_nmi().
-
- (The reason that NMI is special is that prepare_exit_to_usermode() can
- enable IRQs. In NMI context, NMIs are blocked, and we don't want to
- enable IRQs with NMIs blocked.)
+ command line. The mitigation is enabled through the feature flag
+ X86_FEATURE_CLEAR_CPU_BUF.
+
+ The mitigation is invoked just before transitioning to userspace after
+ user registers are restored. This is done to minimize the window in
+ which kernel data could be accessed after VERW e.g. via an NMI after
+ VERW.
+
+ **Corner case not handled**
+ Interrupts returning to kernel don't clear CPUs buffers since the
+ exit-to-user path is expected to do that anyways. But, there could be
+ a case when an NMI is generated in kernel after the exit-to-user path
+ has cleared the buffers. This case is not handled and NMI returning to
+ kernel don't clear CPU buffers because:
+
+ 1. It is rare to get an NMI after VERW, but before returning to userspace.
+ 2. For an unprivileged user, there is no known way to make that NMI
+ less rare or target it.
+ 3. It would take a large number of these precisely-timed NMIs to mount
+ an actual attack. There's presumably not enough bandwidth.
+ 4. The NMI in question occurs after a VERW, i.e. when user state is
+ restored and most interesting data is already scrubbed. Whats left
+ is only the data that NMI touches, and that may or may not be of
+ any interest.
2. C-State transition
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-23 00:23:20 +0000