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2020-12-02media: rcar-vin: Rework CSI-2 firmware parsingNiklas Söderlund
Rework the CSI-2 firmware parsing code to not use the soon to be removed v4l2_async_notifier_parse_fwnode_endpoints_by_port() helper. The change only aims to prepare for the removing of the old helper and there are no functional change. Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se> Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
2020-12-02media: rcar-vin: Use v4l2_async_subdev instead of fwnode_handle to match ↵Niklas Söderlund
subdevices In preparation of removing the usage of the old helper v4l2_async_notifier_parse_fwnode_endpoints_by_port() use the v4l2_async_subdev instead of fwnode_handle to match subdevices. Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se> Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
2020-12-02media: rcar-vin: Rework parallel firmware parsingNiklas Söderlund
Rework the parallel firmware parsing code to not use the soon to be removed v4l2_async_notifier_parse_fwnode_endpoints_by_port() helper. The change only aims to prepare for the removing of the old helper and there are no functional change. Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se> Reviewed-by: Jacopo Mondi <jacopo+renesas@jmondi.org> Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
2020-12-02media: rcar-vin: Only dynamically allocate v4l2_async_subdevNiklas Söderlund
In preparation of removing the usage of the old helper v4l2_async_notifier_parse_fwnode_endpoints_by_port() do not dynamically allocate the whole structure containing the parameters for the parallel interface, instead only allocate the v4l2_async_subdev structure. There is no functional change. Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se> Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
2020-12-02media: ov2740: fix dereference before null check on pointer nvmColin Ian King
Currently pointer nvm is being dereferenced before it is being null checked. Fix this by moving the assignments of pointers client and ov2740 so that are after the null check hence avoiding any potential null pointer dereferences on pointer nvm. Fixes: 5e6fd339b68d ("media: ov2740: allow OTP data access during streaming") Signed-off-by: Colin Ian King <colin.king@canonical.com> Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
2020-12-02media: i2c: add OV02A10 image sensor driverDongchun Zhu
Add a V4L2 sub-device driver for OmniVision OV02A10 image sensor. Signed-off-by: Dongchun Zhu <dongchun.zhu@mediatek.com> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
2020-12-02media: dt-bindings: media: i2c: document OV02A10 DT bindingsDongchun Zhu
Add device-tree binding documentation for OV02A10 image sensor driver, and the relevant MAINTAINERS entries. Signed-off-by: Dongchun Zhu <dongchun.zhu@mediatek.com> Reviewed-by: Rob Herring <robh@kernel.org> Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
2020-12-02media: ov9734: hold lock to check streaming stateBingbu Cao
The lock in ov9734 is used to protect the streaming state and serialize the stream on and off callbacks, it should be hold before checking the streaming state in ov9734_set_stream(). Reported-by: Tomasz Figa <tfiga@chromium.org> Reported-by: Sergey Senozhatsky <senozhatsky@chromium.org> Signed-off-by: Bingbu Cao <bingbu.cao@intel.com> Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
2020-12-02media: v4l: subdev: Set sd->devnode before registering the subdevSakari Ailus
The subdev's video device node was only assigned after registering the device node in the system. While it is unlikely that a driver needed to use this field in handling system calls to its file handle, there remains a slim chance the devnode field remains NULL while the driver expects to find a video node there. Assign the devnode field before registering the device, and assign it back to NULL if the registration failed. Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com> Reviewed-by: Hans Verkuil <hverkuil-cisco@xs4all.nl> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
2020-12-02media: omap3isp: Remove misleading commentThomas Gleixner
in_interrupt() covers hard and soft interrupt servicing and bottom half disabled contexts, which is semantically undefined and useless. The comment for __ccdc_lsc_configure() "Context: in_interrupt()" is therefore as useful as "Context: unknown'. Remove it. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
2020-12-02media: ccs: Request for "reset" GPIOSakari Ailus
The DT bindings documented "reset-gpios" property but the driver never made use of it. Instead it used a GPIO called "xshutdown", with apprently wrong polarity. Fix this by requesting "reset" GPIO with the right polarity first, and if that fails, then request "xshutdown" GPIO with the old polarity. This way it works for new users as expected while if someone, somewhere, depended on "xshutdown" GPIO, that continues to work as well. Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
2020-12-02media: dt-bindings: mipi-ccs: Add bus-type for C-PHY supportSakari Ailus
The bus-type property is required for C-PHY support. Add it, including values for CCP2 and CSI-2 D-PHY. Also require the bus-type property. Effectively all new sensors are MIPI D-PHY or C-PHY that cannot be told apart without the bus-type property. Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com> Reviewed-by: Rob Herring <robh@kernel.org> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
2020-12-02media: dt-bindings: nokia,smia: Amend SMIA bindings with MIPI CCS supportSakari Ailus
Amend the existing SMIA bindings by adding MIPI CCS support, with separate compatible strings for CCS 1.0 and CCS 1.1. Rename the old bindings accordingly as CCS is the current standard. Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com> Reviewed-by: Rob Herring <robh@kernel.org> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
2020-12-02media: dt-bindings: nokia,smia: Use better active polarity for resetSakari Ailus
Generally reset signal is active low on camera sensors. The example had it high. Make it low, and use GPIO_ACTIVE_LOW in gpio.h for that. Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com> Acked-by: Rob Herring <robh@kernel.org> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
2020-12-02media: dt-bindings: nokia,smia: Convert to YAMLSakari Ailus
Convert nokia,smia DT bindings to YAML. Also add explicit license to bindings. Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com> Reviewed-by: Rob Herring <robh@kernel.org> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
2020-12-02media: dt-bindings: nokia,smia: Remove nokia,nvm-size propertySakari Ailus
nokia,nvm-size property was removed from the bindings but it was left in the example. Remove it from the example, too. Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com> Acked-by: Rob Herring <robh@kernel.org> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
2020-12-02media: dt-bindings: nokia,smia: Make vana-supply optionalSakari Ailus
vana-supply is optional in the spec, therefore make it optional in bindings, too. Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com> Acked-by: Rob Herring <robh@kernel.org> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
2020-12-02media: dt-bindings: nokia,smia: Fix link-frequencies documentationSakari Ailus
The link-frequencies property belongs to the endpoint, not to the node representing the device. Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com> Acked-by: Rob Herring <robh@kernel.org> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
2020-12-02media: ccs: Give all subdevs a functionSakari Ailus
This removes a warning at driver probe time telling that one or two entities have no function set. The function used for both the binner and scaler is the scaler. Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
2020-12-02media: ccs: Remove profile conceptSakari Ailus
The driver doesn't do anything tangible with profiles. Remove the notion, and use the capabilities directly. Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
2020-12-02media: smiapp: Rename as "ccs"Sakari Ailus
Rename the "smiapp" driver as "ccs". MIPI CCS is the contemporary standard for raw Bayer camera sensors. The driver retains support for the SMIA++ and SMIA compliant camera sensors. A module alias is added for old user space using "smiapp" module name. Add Intel copyright while at it. Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
2020-12-02media: smiapp: Differentiate CCS sensors from SMIA in subdev namingSakari Ailus
Call CCS compliant sensors as "ccs" instead of "smiapp" in absence of a device specific name. This is done based on the value of the manufacturer ID register that is only present in CCS. Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
2020-12-02media: smiapp: Internal rename to CCSSakari Ailus
Rename internal names to reflect the driver's new reference. The module name remains the same. Also fix trivial coding style issues on the way related to e.g. alignment changes due to the rename. Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
2020-12-02media: smiapp: Rename register access functionsSakari Ailus
Rename register access functions by changing smiapp to ccs. The functions operating on register addresses have "addr" appended to the name. Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
2020-12-02media: smiapp: Remove quirk function for writing a single 8-bit registerSakari Ailus
This function is no longer needed as the smiapp_write() function can be used to write 8-bit registers with plain register addresses. Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
2020-12-02media: smiapp: Use CCS registersSakari Ailus
Switch to CCS standard registers where they exist. The still relevant SMIA registers are left as-is and the redundant ones are removed. Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
2020-12-02media: smiapp: Use CCS limits in reading binning capabilitiesSakari Ailus
Use CCS limits for obtaining binning capabilities and subtypes. Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
2020-12-02media: smiapp: Use CCS limits in reading data format descriptorsSakari Ailus
The CCS limits have the information so use it instead. Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
2020-12-02media: smiapp: Obtain frame descriptor from CCS limitsSakari Ailus
Obtain the frame descriptor from the CCS limits, instead of reading them directly from the frame descriptor registers. Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
2020-12-02media: smiapp: Switch to CCS limitsSakari Ailus
Use the CCS limit definitions instead of the SMIA ones. This allows accessing CCS capabilities where needed as well as dropping the old SMIA limits. Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
2020-12-02media: smiapp: Read CCS limit valuesSakari Ailus
Read limit and capability values into a driver allocated buffer. This will later replace (most of) the existing SMIA limits. Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
2020-12-02media: smiapp: Use MIPI CCS version and manufacturer ID informationSakari Ailus
Read MIPI CCS manufacturer and version information, and use the CCS IDs over SMIA whenever they are set. Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
2020-12-02media: smiapp: Add macros for accessing CCS registersSakari Ailus
Add two helper macros for reading and writing the CCS registers as defined in ccs-regs.h. Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
2020-12-02media: smiapp: Remove macros for defining registers, merge definitionsSakari Ailus
Remove macros for defining new SMIA registers, instead put the register flags to the register definition itself. Also move the register flags to the same file. This is not expected to be updated but rather left there as a reference. Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
2020-12-02media: smiapp: Calculate CCS limit offsets and limit buffer sizeSakari Ailus
Calculate the limit offsets and the size of the limit buffer. CCS limits are read into this buffer, and the offsets are helpful in accessing the information in it. Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
2020-12-02media: smiapp: Use CCS register flagsSakari Ailus
Use the CCS register flags instead of the old smia flags. The new flags include the register width information that was separate from the register flags previously. Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
2020-12-02media: smiapp: Import CCS definitionsSakari Ailus
Import CCS register and limit definitions. These files are generated by a Perl script based on a text-based register definition file. The generator was added on commit 1ec0b899c2b7 ("media: ccs: Add the generator for CCS register definitions and limits") Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
2020-12-02media: Documentation: ccs: Add CCS driver documentationSakari Ailus
Document the MIPI CCS driver and the C register definition generator. Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
2020-12-02media: ccs: Add the generator for CCS register definitions and limitsSakari Ailus
Add register definitions of the MIPI CCS 1.1 standard. The CCS driver makes extended use of device's capability registers that are dependent on CCS version. This involves having an in-memory data structure for limit and capability information, creating that data structure and accessing it. The register definitions as well as the definitions of this data structure are generated from a text file using a Perl script. Add the generator script to make it easy to update the generated files. Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
2020-12-02entry: Add syscall_exit_to_user_mode_work()Sven Schnelle
This is the same as syscall_exit_to_user_mode() but without calling exit_to_user_mode(). This can be used if there is an architectural reason to avoid the combo function, e.g. restarting a syscall without returning to userspace. Before returning to user space the caller has to invoke exit_to_user_mode(). [ tglx: Amended comments ] Signed-off-by: Sven Schnelle <svens@linux.ibm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20201201142755.31931-6-svens@linux.ibm.com
2020-12-02entry: Add exit_to_user_mode() wrapperSven Schnelle
Called from architecture specific code when syscall_exit_to_user_mode() is not suitable. It simply calls __exit_to_user_mode(). This way __exit_to_user_mode() can still be inlined because it is declared static __always_inline. [ tglx: Amended comments and moved it to a different place in the header ] Signed-off-by: Sven Schnelle <svens@linux.ibm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20201201142755.31931-5-svens@linux.ibm.com
2020-12-02entry_Add_enter_from_user_mode_wrapperSven Schnelle
To be called from architecture specific code if the combo interfaces are not suitable. It simply calls __enter_from_user_mode(). This way __enter_from_user_mode will still be inlined because it is declared static __always_inline. [ tglx: Amend comments and move it to a different location in the header ] Signed-off-by: Sven Schnelle <svens@linux.ibm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20201201142755.31931-4-svens@linux.ibm.com
2020-12-02entry: Rename exit_to_user_mode()Sven Schnelle
In order to make this function publicly available rename it so it can still be inlined. An additional exit_to_user_mode() function will be added with a later commit. Signed-off-by: Sven Schnelle <svens@linux.ibm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20201201142755.31931-3-svens@linux.ibm.com
2020-12-02entry: Rename enter_from_user_mode()Sven Schnelle
In order to make this function publicly available rename it so it can still be inlined. An additional enter_from_user_mode() function will be added with a later commit. Signed-off-by: Sven Schnelle <svens@linux.ibm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20201201142755.31931-2-svens@linux.ibm.com
2020-12-02docs: Document Syscall User DispatchGabriel Krisman Bertazi
Explain the interface, provide some background and security notes. [ tglx: Add note about non-visibility, add it to the index and fix the kerneldoc warning ] Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Andy Lutomirski <luto@kernel.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/r/20201127193238.821364-8-krisman@collabora.com
2020-12-02selftests: Add benchmark for syscall user dispatchGabriel Krisman Bertazi
This is the patch I'm using to evaluate the impact syscall user dispatch has on native syscall (syscalls not redirected to userspace) when enabled for the process and submiting syscalls though the unblocked dispatch selector. It works by running a step to define a baseline of the cost of executing sysinfo, then enabling SUD, and rerunning that step. On my test machine, an AMD Ryzen 5 1500X, I have the following results with the latest version of syscall user dispatch patches. root@olga:~# syscall_user_dispatch/sud_benchmark Calibrating test set to last ~5 seconds... test iterations = 37500000 Avg syscall time 134ns. Caught sys_ff00 trapped_call_count 1, native_call_count 0. Avg syscall time 147ns. Interception overhead: 9.7% (+13ns). Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Andy Lutomirski <luto@kernel.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/r/20201127193238.821364-7-krisman@collabora.com
2020-12-02selftests: Add kselftest for syscall user dispatchGabriel Krisman Bertazi
Implement functionality tests for syscall user dispatch. In order to make the test portable, refrain from open coding syscall dispatchers and calculating glibc memory ranges. Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Andy Lutomirski <luto@kernel.org> Acked-by: Kees Cook <keescook@chromium.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/r/20201127193238.821364-6-krisman@collabora.com
2020-12-02entry: Support Syscall User Dispatch on common syscall entryGabriel Krisman Bertazi
Syscall User Dispatch (SUD) must take precedence over seccomp and ptrace, since the use case is emulation (it can be invoked with a different ABI) such that seccomp filtering by syscall number doesn't make sense in the first place. In addition, either the syscall is dispatched back to userspace, in which case there is no resource for to trace, or the syscall will be executed, and seccomp/ptrace will execute next. Since SUD runs before tracepoints, it needs to be a SYSCALL_WORK_EXIT as well, just to prevent a trace exit event when dispatch was triggered. For that, the on_syscall_dispatch() examines context to skip the tracepoint, audit and other work. [ tglx: Add a comment on the exit side ] Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Andy Lutomirski <luto@kernel.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20201127193238.821364-5-krisman@collabora.com
2020-12-02kernel: Implement selective syscall userspace redirectionGabriel Krisman Bertazi
Introduce a mechanism to quickly disable/enable syscall handling for a specific process and redirect to userspace via SIGSYS. This is useful for processes with parts that require syscall redirection and parts that don't, but who need to perform this boundary crossing really fast, without paying the cost of a system call to reconfigure syscall handling on each boundary transition. This is particularly important for Windows games running over Wine. The proposed interface looks like this: prctl(PR_SET_SYSCALL_USER_DISPATCH, <op>, <off>, <length>, [selector]) The range [<offset>,<offset>+<length>) is a part of the process memory map that is allowed to by-pass the redirection code and dispatch syscalls directly, such that in fast paths a process doesn't need to disable the trap nor the kernel has to check the selector. This is essential to return from SIGSYS to a blocked area without triggering another SIGSYS from rt_sigreturn. selector is an optional pointer to a char-sized userspace memory region that has a key switch for the mechanism. This key switch is set to either PR_SYS_DISPATCH_ON, PR_SYS_DISPATCH_OFF to enable and disable the redirection without calling the kernel. The feature is meant to be set per-thread and it is disabled on fork/clone/execv. Internally, this doesn't add overhead to the syscall hot path, and it requires very little per-architecture support. I avoided using seccomp, even though it duplicates some functionality, due to previous feedback that maybe it shouldn't mix with seccomp since it is not a security mechanism. And obviously, this should never be considered a security mechanism, since any part of the program can by-pass it by using the syscall dispatcher. For the sysinfo benchmark, which measures the overhead added to executing a native syscall that doesn't require interception, the overhead using only the direct dispatcher region to issue syscalls is pretty much irrelevant. The overhead of using the selector goes around 40ns for a native (unredirected) syscall in my system, and it is (as expected) dominated by the supervisor-mode user-address access. In fact, with SMAP off, the overhead is consistently less than 5ns on my test box. Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Andy Lutomirski <luto@kernel.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20201127193238.821364-4-krisman@collabora.com
2020-12-02media: vidtv: fix kernel-doc markupsMauro Carvalho Chehab
Some functions has a different name between their prototypes and the corresponding kernel-doc markups. Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>