Merge "Merge tag 'android12-5.10.136_r00' into android12-5.10" into android12-5.10

This commit is contained in:
Treehugger Robot
2022-09-28 14:31:50 +00:00
1582 changed files with 21908 additions and 14306 deletions

View File

@@ -107,13 +107,14 @@ Description:
described in ATA8 7.16 and 7.17. Only valid if
the device is not a PM.
pio_mode: (RO) Transfer modes supported by the device when
in PIO mode. Mostly used by PATA device.
pio_mode: (RO) PIO transfer mode used by the device.
Mostly used by PATA devices.
xfer_mode: (RO) Current transfer mode
xfer_mode: (RO) Current transfer mode. Mostly used by
PATA devices.
dma_mode: (RO) Transfer modes supported by the device when
in DMA mode. Mostly used by PATA device.
dma_mode: (RO) DMA transfer mode used by the device.
Mostly used by PATA devices.
class: (RO) Device class. Can be "ata" for disk,
"atapi" for packet device, "pmp" for PM, or

View File

@@ -1,4 +1,4 @@
What: /sys/bus/iio/devices/iio:deviceX/conversion_mode
What: /sys/bus/iio/devices/iio:deviceX/in_conversion_mode
KernelVersion: 4.2
Contact: linux-iio@vger.kernel.org
Description:

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@@ -519,6 +519,7 @@ What: /sys/devices/system/cpu/vulnerabilities
/sys/devices/system/cpu/vulnerabilities/srbds
/sys/devices/system/cpu/vulnerabilities/tsx_async_abort
/sys/devices/system/cpu/vulnerabilities/itlb_multihit
/sys/devices/system/cpu/vulnerabilities/mmio_stale_data
Date: January 2018
Contact: Linux kernel mailing list <linux-kernel@vger.kernel.org>
Description: Information about CPU vulnerabilities

View File

@@ -15,3 +15,4 @@ are configurable at compile, boot or run time.
tsx_async_abort
multihit.rst
special-register-buffer-data-sampling.rst
processor_mmio_stale_data.rst

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@@ -0,0 +1,246 @@
=========================================
Processor MMIO Stale Data Vulnerabilities
=========================================
Processor MMIO Stale Data Vulnerabilities are a class of memory-mapped I/O
(MMIO) vulnerabilities that can expose data. The sequences of operations for
exposing data range from simple to very complex. Because most of the
vulnerabilities require the attacker to have access to MMIO, many environments
are not affected. System environments using virtualization where MMIO access is
provided to untrusted guests may need mitigation. These vulnerabilities are
not transient execution attacks. However, these vulnerabilities may propagate
stale data into core fill buffers where the data can subsequently be inferred
by an unmitigated transient execution attack. Mitigation for these
vulnerabilities includes a combination of microcode update and software
changes, depending on the platform and usage model. Some of these mitigations
are similar to those used to mitigate Microarchitectural Data Sampling (MDS) or
those used to mitigate Special Register Buffer Data Sampling (SRBDS).
Data Propagators
================
Propagators are operations that result in stale data being copied or moved from
one microarchitectural buffer or register to another. Processor MMIO Stale Data
Vulnerabilities are operations that may result in stale data being directly
read into an architectural, software-visible state or sampled from a buffer or
register.
Fill Buffer Stale Data Propagator (FBSDP)
-----------------------------------------
Stale data may propagate from fill buffers (FB) into the non-coherent portion
of the uncore on some non-coherent writes. Fill buffer propagation by itself
does not make stale data architecturally visible. Stale data must be propagated
to a location where it is subject to reading or sampling.
Sideband Stale Data Propagator (SSDP)
-------------------------------------
The sideband stale data propagator (SSDP) is limited to the client (including
Intel Xeon server E3) uncore implementation. The sideband response buffer is
shared by all client cores. For non-coherent reads that go to sideband
destinations, the uncore logic returns 64 bytes of data to the core, including
both requested data and unrequested stale data, from a transaction buffer and
the sideband response buffer. As a result, stale data from the sideband
response and transaction buffers may now reside in a core fill buffer.
Primary Stale Data Propagator (PSDP)
------------------------------------
The primary stale data propagator (PSDP) is limited to the client (including
Intel Xeon server E3) uncore implementation. Similar to the sideband response
buffer, the primary response buffer is shared by all client cores. For some
processors, MMIO primary reads will return 64 bytes of data to the core fill
buffer including both requested data and unrequested stale data. This is
similar to the sideband stale data propagator.
Vulnerabilities
===============
Device Register Partial Write (DRPW) (CVE-2022-21166)
-----------------------------------------------------
Some endpoint MMIO registers incorrectly handle writes that are smaller than
the register size. Instead of aborting the write or only copying the correct
subset of bytes (for example, 2 bytes for a 2-byte write), more bytes than
specified by the write transaction may be written to the register. On
processors affected by FBSDP, this may expose stale data from the fill buffers
of the core that created the write transaction.
Shared Buffers Data Sampling (SBDS) (CVE-2022-21125)
----------------------------------------------------
After propagators may have moved data around the uncore and copied stale data
into client core fill buffers, processors affected by MFBDS can leak data from
the fill buffer. It is limited to the client (including Intel Xeon server E3)
uncore implementation.
Shared Buffers Data Read (SBDR) (CVE-2022-21123)
------------------------------------------------
It is similar to Shared Buffer Data Sampling (SBDS) except that the data is
directly read into the architectural software-visible state. It is limited to
the client (including Intel Xeon server E3) uncore implementation.
Affected Processors
===================
Not all the CPUs are affected by all the variants. For instance, most
processors for the server market (excluding Intel Xeon E3 processors) are
impacted by only Device Register Partial Write (DRPW).
Below is the list of affected Intel processors [#f1]_:
=================== ============ =========
Common name Family_Model Steppings
=================== ============ =========
HASWELL_X 06_3FH 2,4
SKYLAKE_L 06_4EH 3
BROADWELL_X 06_4FH All
SKYLAKE_X 06_55H 3,4,6,7,11
BROADWELL_D 06_56H 3,4,5
SKYLAKE 06_5EH 3
ICELAKE_X 06_6AH 4,5,6
ICELAKE_D 06_6CH 1
ICELAKE_L 06_7EH 5
ATOM_TREMONT_D 06_86H All
LAKEFIELD 06_8AH 1
KABYLAKE_L 06_8EH 9 to 12
ATOM_TREMONT 06_96H 1
ATOM_TREMONT_L 06_9CH 0
KABYLAKE 06_9EH 9 to 13
COMETLAKE 06_A5H 2,3,5
COMETLAKE_L 06_A6H 0,1
ROCKETLAKE 06_A7H 1
=================== ============ =========
If a CPU is in the affected processor list, but not affected by a variant, it
is indicated by new bits in MSR IA32_ARCH_CAPABILITIES. As described in a later
section, mitigation largely remains the same for all the variants, i.e. to
clear the CPU fill buffers via VERW instruction.
New bits in MSRs
================
Newer processors and microcode update on existing affected processors added new
bits to IA32_ARCH_CAPABILITIES MSR. These bits can be used to enumerate
specific variants of Processor MMIO Stale Data vulnerabilities and mitigation
capability.
MSR IA32_ARCH_CAPABILITIES
--------------------------
Bit 13 - SBDR_SSDP_NO - When set, processor is not affected by either the
Shared Buffers Data Read (SBDR) vulnerability or the sideband stale
data propagator (SSDP).
Bit 14 - FBSDP_NO - When set, processor is not affected by the Fill Buffer
Stale Data Propagator (FBSDP).
Bit 15 - PSDP_NO - When set, processor is not affected by Primary Stale Data
Propagator (PSDP).
Bit 17 - FB_CLEAR - When set, VERW instruction will overwrite CPU fill buffer
values as part of MD_CLEAR operations. Processors that do not
enumerate MDS_NO (meaning they are affected by MDS) but that do
enumerate support for both L1D_FLUSH and MD_CLEAR implicitly enumerate
FB_CLEAR as part of their MD_CLEAR support.
Bit 18 - FB_CLEAR_CTRL - Processor supports read and write to MSR
IA32_MCU_OPT_CTRL[FB_CLEAR_DIS]. On such processors, the FB_CLEAR_DIS
bit can be set to cause the VERW instruction to not perform the
FB_CLEAR action. Not all processors that support FB_CLEAR will support
FB_CLEAR_CTRL.
MSR IA32_MCU_OPT_CTRL
---------------------
Bit 3 - FB_CLEAR_DIS - When set, VERW instruction does not perform the FB_CLEAR
action. This may be useful to reduce the performance impact of FB_CLEAR in
cases where system software deems it warranted (for example, when performance
is more critical, or the untrusted software has no MMIO access). Note that
FB_CLEAR_DIS has no impact on enumeration (for example, it does not change
FB_CLEAR or MD_CLEAR enumeration) and it may not be supported on all processors
that enumerate FB_CLEAR.
Mitigation
==========
Like MDS, all variants of Processor MMIO Stale Data vulnerabilities have 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.
Kernel reuses the MDS function to invoke the buffer clearing:
mds_clear_cpu_buffers()
On MDS affected CPUs, the kernel already invokes CPU buffer clear on
kernel/userspace, hypervisor/guest and C-state (idle) transitions. No
additional mitigation is needed on such CPUs.
For CPUs not affected by MDS or TAA, mitigation is needed only for the attacker
with MMIO capability. Therefore, VERW is not required for kernel/userspace. For
virtualization case, VERW is only needed at VMENTER for a guest with MMIO
capability.
Mitigation points
-----------------
Return to user space
^^^^^^^^^^^^^^^^^^^^
Same mitigation as MDS when affected by MDS/TAA, otherwise no mitigation
needed.
C-State transition
^^^^^^^^^^^^^^^^^^
Control register writes by CPU during C-state transition can propagate data
from fill buffer to uncore buffers. Execute VERW before C-state transition to
clear CPU fill buffers.
Guest entry point
^^^^^^^^^^^^^^^^^
Same mitigation as MDS when processor is also affected by MDS/TAA, otherwise
execute VERW at VMENTER only for MMIO capable guests. On CPUs not affected by
MDS/TAA, guest without MMIO access cannot extract secrets using Processor MMIO
Stale Data vulnerabilities, so there is no need to execute VERW for such guests.
Mitigation control on the kernel command line
---------------------------------------------
The kernel command line allows to control the Processor MMIO Stale Data
mitigations at boot time with the option "mmio_stale_data=". The valid
arguments for this option are:
========== =================================================================
full If the CPU is vulnerable, enable mitigation; CPU buffer clearing
on exit to userspace and when entering a VM. Idle transitions are
protected as well. It does not automatically disable SMT.
full,nosmt Same as full, with SMT disabled on vulnerable CPUs. This is the
complete mitigation.
off Disables mitigation completely.
========== =================================================================
If the CPU is affected and mmio_stale_data=off is not supplied on the kernel
command line, then the kernel selects the appropriate mitigation.
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/mmio_stale_data
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: Clear CPU buffers attempted, no microcode'
- The processor is vulnerable, but microcode is not updated. The
mitigation is enabled on a best effort basis.
* - 'Mitigation: Clear CPU buffers'
- The processor is vulnerable and the CPU buffer clearing mitigation is
enabled.
If the processor is vulnerable then the following information is appended to
the above information:
======================== ===========================================
'SMT vulnerable' SMT is enabled
'SMT disabled' SMT is disabled
'SMT Host state unknown' Kernel runs in a VM, Host SMT state unknown
======================== ===========================================
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

View File

@@ -422,6 +422,14 @@ The possible values in this file are:
'RSB filling' Protection of RSB on context switch enabled
============= ===========================================
- EIBRS Post-barrier Return Stack Buffer (PBRSB) protection status:
=========================== =======================================================
'PBRSB-eIBRS: SW sequence' CPU is affected and protection of RSB on VMEXIT enabled
'PBRSB-eIBRS: Vulnerable' CPU is vulnerable
'PBRSB-eIBRS: Not affected' CPU is not affected by PBRSB
=========================== =======================================================
Full mitigation might require a microcode update from the CPU
vendor. When the necessary microcode is not available, the kernel will
report vulnerability.

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@@ -2932,6 +2932,8 @@
kvm.nx_huge_pages=off [X86]
no_entry_flush [PPC]
no_uaccess_flush [PPC]
mmio_stale_data=off [X86]
retbleed=off [X86]
Exceptions:
This does not have any effect on
@@ -2953,6 +2955,8 @@
Equivalent to: l1tf=flush,nosmt [X86]
mds=full,nosmt [X86]
tsx_async_abort=full,nosmt [X86]
mmio_stale_data=full,nosmt [X86]
retbleed=auto,nosmt [X86]
mminit_loglevel=
[KNL] When CONFIG_DEBUG_MEMORY_INIT is set, this
@@ -2962,6 +2966,40 @@
log everything. Information is printed at KERN_DEBUG
so loglevel=8 may also need to be specified.
mmio_stale_data=
[X86,INTEL] Control mitigation for the Processor
MMIO Stale Data vulnerabilities.
Processor MMIO Stale Data is a class of
vulnerabilities that may expose data after an MMIO
operation. Exposed data could originate or end in
the same CPU buffers as affected by MDS and TAA.
Therefore, similar to MDS and TAA, the mitigation
is to clear the affected CPU buffers.
This parameter controls the mitigation. The
options are:
full - Enable mitigation on vulnerable CPUs
full,nosmt - Enable mitigation and disable SMT on
vulnerable CPUs.
off - Unconditionally disable mitigation
On MDS or TAA affected machines,
mmio_stale_data=off can be prevented by an active
MDS or TAA mitigation as these vulnerabilities are
mitigated with the same mechanism so in order to
disable this mitigation, you need to specify
mds=off and tsx_async_abort=off too.
Not specifying this option is equivalent to
mmio_stale_data=full.
For details see:
Documentation/admin-guide/hw-vuln/processor_mmio_stale_data.rst
module.sig_enforce
[KNL] When CONFIG_MODULE_SIG is set, this means that
modules without (valid) signatures will fail to load.
@@ -4136,6 +4174,12 @@
fully seed the kernel's CRNG. Default is controlled
by CONFIG_RANDOM_TRUST_CPU.
random.trust_bootloader={on,off}
[KNL] Enable or disable trusting the use of a
seed passed by the bootloader (if available) to
fully seed the kernel's CRNG. Default is controlled
by CONFIG_RANDOM_TRUST_BOOTLOADER.
ras=option[,option,...] [KNL] RAS-specific options
cec_disable [X86]
@@ -4715,6 +4759,30 @@
retain_initrd [RAM] Keep initrd memory after extraction
retbleed= [X86] Control mitigation of RETBleed (Arbitrary
Speculative Code Execution with Return Instructions)
vulnerability.
off - no mitigation
auto - automatically select a migitation
auto,nosmt - automatically select a mitigation,
disabling SMT if necessary for
the full mitigation (only on Zen1
and older without STIBP).
ibpb - mitigate short speculation windows on
basic block boundaries too. Safe, highest
perf impact.
unret - force enable untrained return thunks,
only effective on AMD f15h-f17h
based systems.
unret,nosmt - like unret, will disable SMT when STIBP
is not available.
Selecting 'auto' will choose a mitigation method at run
time according to the CPU.
Not specifying this option is equivalent to retbleed=auto.
rfkill.default_state=
0 "airplane mode". All wifi, bluetooth, wimax, gps, fm,
etc. communication is blocked by default.
@@ -5064,6 +5132,7 @@
eibrs - enhanced IBRS
eibrs,retpoline - enhanced IBRS + Retpolines
eibrs,lfence - enhanced IBRS + LFENCE
ibrs - use IBRS to protect kernel
Not specifying this option is equivalent to
spectre_v2=auto.

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@@ -1006,28 +1006,22 @@ This is a directory, with the following entries:
* ``boot_id``: a UUID generated the first time this is retrieved, and
unvarying after that;
* ``uuid``: a UUID generated every time this is retrieved (this can
thus be used to generate UUIDs at will);
* ``entropy_avail``: the pool's entropy count, in bits;
* ``poolsize``: the entropy pool size, in bits;
* ``urandom_min_reseed_secs``: obsolete (used to determine the minimum
number of seconds between urandom pool reseeding).
* ``uuid``: a UUID generated every time this is retrieved (this can
thus be used to generate UUIDs at will);
number of seconds between urandom pool reseeding). This file is
writable for compatibility purposes, but writing to it has no effect
on any RNG behavior;
* ``write_wakeup_threshold``: when the entropy count drops below this
(as a number of bits), processes waiting to write to ``/dev/random``
are woken up.
If ``drivers/char/random.c`` is built with ``ADD_INTERRUPT_BENCH``
defined, these additional entries are present:
* ``add_interrupt_avg_cycles``: the average number of cycles between
interrupts used to feed the pool;
* ``add_interrupt_avg_deviation``: the standard deviation seen on the
number of cycles between interrupts used to feed the pool.
are woken up. This file is writable for compatibility purposes, but
writing to it has no effect on any RNG behavior.
randomize_va_space

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@@ -166,6 +166,9 @@ stable kernels.
+----------------+-----------------+-----------------+-----------------------------+
| Qualcomm Tech. | Kryo4xx Silver | N/A | ARM64_ERRATUM_1024718 |
+----------------+-----------------+-----------------+-----------------------------+
| Qualcomm Tech. | Kryo4xx Gold | N/A | ARM64_ERRATUM_1286807 |
+----------------+-----------------+-----------------+-----------------------------+
+----------------+-----------------+-----------------+-----------------------------+
| Fujitsu | A64FX | E#010001 | FUJITSU_ERRATUM_010001 |
+----------------+-----------------+-----------------+-----------------------------+

View File

@@ -176,7 +176,7 @@ finally:
#
# This is also used if you do content translation via gettext catalogs.
# Usually you set "language" from the command line for these cases.
language = None
language = 'en'
# There are two options for replacing |today|: either, you set today to some
# non-false value, then it is used:

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@@ -130,11 +130,3 @@ accesses to DMA buffers in both privileged "supervisor" and unprivileged
subsystem that the buffer is fully accessible at the elevated privilege
level (and ideally inaccessible or at least read-only at the
lesser-privileged levels).
DMA_ATTR_OVERWRITE
------------------
This is a hint to the DMA-mapping subsystem that the device is expected to
overwrite the entire mapped size, thus the caller does not require any of the
previous buffer contents to be preserved. This allows bounce-buffering
implementations to optimise DMA_FROM_DEVICE transfers.

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@@ -72,6 +72,7 @@ examples:
dc-gpios = <&gpio 43 GPIO_ACTIVE_HIGH>;
reset-gpios = <&gpio 80 GPIO_ACTIVE_HIGH>;
rotation = <270>;
backlight = <&backlight>;
};
};

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@@ -61,7 +61,7 @@ if:
then:
properties:
clocks:
maxItems: 2
minItems: 2
required:
- clock-names

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@@ -9,8 +9,9 @@ Required properties:
- The second cell is reserved and is currently unused.
- gpio-controller : Marks the device node as a GPIO controller.
- interrupt-controller: Mark the device node as an interrupt controller
- #interrupt-cells : Should be 1. The interrupt type is fixed in the hardware.
- #interrupt-cells : Should be 2. The interrupt type is fixed in the hardware.
- The first cell is the GPIO offset number within the GPIO controller.
- The second cell is the interrupt trigger type and level flags.
- interrupts: Specify the interrupt.
- altr,interrupt-type: Specifies the interrupt trigger type the GPIO
hardware is synthesized. This field is required if the Altera GPIO controller
@@ -38,6 +39,6 @@ gpio_altr: gpio@ff200000 {
altr,interrupt-type = <IRQ_TYPE_EDGE_RISING>;
#gpio-cells = <2>;
gpio-controller;
#interrupt-cells = <1>;
#interrupt-cells = <2>;
interrupt-controller;
};

View File

@@ -58,7 +58,7 @@ patternProperties:
$ref: "/schemas/types.yaml#/definitions/string"
enum: [ ADC0, ADC1, ADC10, ADC11, ADC12, ADC13, ADC14, ADC15, ADC2,
ADC3, ADC4, ADC5, ADC6, ADC7, ADC8, ADC9, BMCINT, EMMCG1, EMMCG4,
EMMCG8, ESPI, ESPIALT, FSI1, FSI2, FWSPIABR, FWSPID, FWQSPID, FWSPIWP,
EMMCG8, ESPI, ESPIALT, FSI1, FSI2, FWSPIABR, FWSPID, FWSPIWP,
GPIT0, GPIT1, GPIT2, GPIT3, GPIT4, GPIT5, GPIT6, GPIT7, GPIU0, GPIU1,
GPIU2, GPIU3, GPIU4, GPIU5, GPIU6, GPIU7, HVI3C3, HVI3C4, I2C1, I2C10,
I2C11, I2C12, I2C13, I2C14, I2C15, I2C16, I2C2, I2C3, I2C4, I2C5,

View File

@@ -45,6 +45,7 @@ properties:
maxItems: 2
interconnect-names:
minItems: 1
items:
- const: qspi-config
- const: qspi-memory

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@@ -988,7 +988,7 @@ cipso_cache_enable - BOOLEAN
cipso_cache_bucket_size - INTEGER
The CIPSO label cache consists of a fixed size hash table with each
hash bucket containing a number of cache entries. This variable limits
the number of entries in each hash bucket; the larger the value the
the number of entries in each hash bucket; the larger the value is, the
more CIPSO label mappings that can be cached. When the number of
entries in a given hash bucket reaches this limit adding new entries
causes the oldest entry in the bucket to be removed to make room.
@@ -1093,7 +1093,7 @@ ip_autobind_reuse - BOOLEAN
option should only be set by experts.
Default: 0
ip_dynaddr - BOOLEAN
ip_dynaddr - INTEGER
If set non-zero, enables support for dynamic addresses.
If set to a non-zero value larger than 1, a kernel log
message will be printed when dynamic address rewriting
@@ -2642,7 +2642,14 @@ sctp_rmem - vector of 3 INTEGERs: min, default, max
Default: 4K
sctp_wmem - vector of 3 INTEGERs: min, default, max
Currently this tunable has no effect.
Only the first value ("min") is used, "default" and "max" are
ignored.
min: Minimum size of send buffer that can be used by SCTP sockets.
It is guaranteed to each SCTP socket (but not association) even
under moderate memory pressure.
Default: 4K
addr_scope_policy - INTEGER
Control IPv4 address scoping - draft-stewart-tsvwg-sctp-ipv4-00

View File

@@ -10,18 +10,177 @@ Introduction
The following is a random collection of documentation regarding
network devices.
struct net_device allocation rules
==================================
struct net_device lifetime rules
================================
Network device structures need to persist even after module is unloaded and
must be allocated with alloc_netdev_mqs() and friends.
If device has registered successfully, it will be freed on last use
by free_netdev(). This is required to handle the pathologic case cleanly
(example: rmmod mydriver </sys/class/net/myeth/mtu )
by free_netdev(). This is required to handle the pathological case cleanly
(example: ``rmmod mydriver </sys/class/net/myeth/mtu``)
alloc_netdev_mqs()/alloc_netdev() reserve extra space for driver
alloc_netdev_mqs() / alloc_netdev() reserve extra space for driver
private data which gets freed when the network device is freed. If
separately allocated data is attached to the network device
(netdev_priv(dev)) then it is up to the module exit handler to free that.
(netdev_priv()) then it is up to the module exit handler to free that.
There are two groups of APIs for registering struct net_device.
First group can be used in normal contexts where ``rtnl_lock`` is not already
held: register_netdev(), unregister_netdev().
Second group can be used when ``rtnl_lock`` is already held:
register_netdevice(), unregister_netdevice(), free_netdevice().
Simple drivers
--------------
Most drivers (especially device drivers) handle lifetime of struct net_device
in context where ``rtnl_lock`` is not held (e.g. driver probe and remove paths).
In that case the struct net_device registration is done using
the register_netdev(), and unregister_netdev() functions:
.. code-block:: c
int probe()
{
struct my_device_priv *priv;
int err;
dev = alloc_netdev_mqs(...);
if (!dev)
return -ENOMEM;
priv = netdev_priv(dev);
/* ... do all device setup before calling register_netdev() ...
*/
err = register_netdev(dev);
if (err)
goto err_undo;
/* net_device is visible to the user! */
err_undo:
/* ... undo the device setup ... */
free_netdev(dev);
return err;
}
void remove()
{
unregister_netdev(dev);
free_netdev(dev);
}
Note that after calling register_netdev() the device is visible in the system.
Users can open it and start sending / receiving traffic immediately,
or run any other callback, so all initialization must be done prior to
registration.
unregister_netdev() closes the device and waits for all users to be done
with it. The memory of struct net_device itself may still be referenced
by sysfs but all operations on that device will fail.
free_netdev() can be called after unregister_netdev() returns on when
register_netdev() failed.
Device management under RTNL
----------------------------
Registering struct net_device while in context which already holds
the ``rtnl_lock`` requires extra care. In those scenarios most drivers
will want to make use of struct net_device's ``needs_free_netdev``
and ``priv_destructor`` members for freeing of state.
Example flow of netdev handling under ``rtnl_lock``:
.. code-block:: c
static void my_setup(struct net_device *dev)
{
dev->needs_free_netdev = true;
}
static void my_destructor(struct net_device *dev)
{
some_obj_destroy(priv->obj);
some_uninit(priv);
}
int create_link()
{
struct my_device_priv *priv;
int err;
ASSERT_RTNL();
dev = alloc_netdev(sizeof(*priv), "net%d", NET_NAME_UNKNOWN, my_setup);
if (!dev)
return -ENOMEM;
priv = netdev_priv(dev);
/* Implicit constructor */
err = some_init(priv);
if (err)
goto err_free_dev;
priv->obj = some_obj_create();
if (!priv->obj) {
err = -ENOMEM;
goto err_some_uninit;
}
/* End of constructor, set the destructor: */
dev->priv_destructor = my_destructor;
err = register_netdevice(dev);
if (err)
/* register_netdevice() calls destructor on failure */
goto err_free_dev;
/* If anything fails now unregister_netdevice() (or unregister_netdev())
* will take care of calling my_destructor and free_netdev().
*/
return 0;
err_some_uninit:
some_uninit(priv);
err_free_dev:
free_netdev(dev);
return err;
}
If struct net_device.priv_destructor is set it will be called by the core
some time after unregister_netdevice(), it will also be called if
register_netdevice() fails. The callback may be invoked with or without
``rtnl_lock`` held.
There is no explicit constructor callback, driver "constructs" the private
netdev state after allocating it and before registration.
Setting struct net_device.needs_free_netdev makes core call free_netdevice()
automatically after unregister_netdevice() when all references to the device
are gone. It only takes effect after a successful call to register_netdevice()
so if register_netdevice() fails driver is responsible for calling
free_netdev().
free_netdev() is safe to call on error paths right after unregister_netdevice()
or when register_netdevice() fails. Parts of netdev (de)registration process
happen after ``rtnl_lock`` is released, therefore in those cases free_netdev()
will defer some of the processing until ``rtnl_lock`` is released.
Devices spawned from struct rtnl_link_ops should never free the
struct net_device directly.
.ndo_init and .ndo_uninit
~~~~~~~~~~~~~~~~~~~~~~~~~
``.ndo_init`` and ``.ndo_uninit`` callbacks are called during net_device
registration and de-registration, under ``rtnl_lock``. Drivers can use
those e.g. when parts of their init process need to run under ``rtnl_lock``.
``.ndo_init`` runs before device is visible in the system, ``.ndo_uninit``
runs during de-registering after device is closed but other subsystems
may still have outstanding references to the netdevice.
MTU
===

View File

@@ -71,7 +71,7 @@ as you intend it to.
The maintainer will thank you if you write your patch description in a
form which can be easily pulled into Linux's source code management
system, ``git``, as a "commit log". See :ref:`explicit_in_reply_to`.
system, ``git``, as a "commit log". See :ref:`the_canonical_patch_format`.
Solve only one problem per patch. If your description starts to get
long, that's a sign that you probably need to split up your patch.

View File

@@ -14702,6 +14702,8 @@ F: arch/mips/generic/board-ranchu.c
RANDOM NUMBER DRIVER
M: "Theodore Ts'o" <tytso@mit.edu>
M: Jason A. Donenfeld <Jason@zx2c4.com>
T: git https://git.kernel.org/pub/scm/linux/kernel/git/crng/random.git
S: Maintained
F: drivers/char/random.c
@@ -19277,7 +19279,8 @@ F: arch/x86/xen/*swiotlb*
F: drivers/xen/*swiotlb*
XFS FILESYSTEM
M: Darrick J. Wong <darrick.wong@oracle.com>
M: Amir Goldstein <amir73il@gmail.com>
M: Darrick J. Wong <djwong@kernel.org>
M: linux-xfs@vger.kernel.org
L: linux-xfs@vger.kernel.org
S: Supported

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