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path: root/drivers/hwtracing/stm/policy.c
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* stm class: Remove an unused functionJiapeng Chong2021-04-161-5/+0
| | | | | | | | | | | | | | Fix the following clang warning: drivers/hwtracing/stm/policy.c:60:21: warning: unused function 'stp_policy_node_name' [-Wunused-function]. Reported-by: Abaci Robot <abaci@linux.alibaba.com> Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com> Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Link: https://lore.kernel.org/r/20210414171251.14672-2-alexander.shishkin@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* stm class: Replace zero-length array with flexible-arrayGustavo A. R. Silva2020-06-151-1/+1
| | | | | | | | | | | | There is a regular need in the kernel to provide a way to declare having a dynamically sized set of trailing elements in a structure. Kernel code should always use “flexible array members”[1] for these cases. The older style of one-element or zero-length arrays should no longer be used[2]. [1] https://en.wikipedia.org/wiki/Flexible_array_member [2] https://github.com/KSPP/linux/issues/21 Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
* stm class: Lose the protocol driver when dropping its referenceAlexander Shishkin2019-11-141-0/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit c7fd62bc69d02 ("stm class: Introduce framing protocol drivers") forgot to tear down the link between an stm device and its protocol driver when policy is removed. This leads to an invalid pointer reference if one tries to write to an stm device after the policy has been removed and the protocol driver module unloaded, leading to the below splat: > BUG: unable to handle page fault for address: ffffffffc0737068 > #PF: supervisor read access in kernel mode > #PF: error_code(0x0000) - not-present page > PGD 3d780f067 P4D 3d780f067 PUD 3d7811067 PMD 492781067 PTE 0 > Oops: 0000 [#1] SMP NOPTI > CPU: 1 PID: 26122 Comm: cat Not tainted 5.4.0-rc5+ #1 > RIP: 0010:stm_output_free+0x40/0xc0 [stm_core] > Call Trace: > stm_char_release+0x3e/0x70 [stm_core] > __fput+0xc6/0x260 > ____fput+0xe/0x10 > task_work_run+0x9d/0xc0 > exit_to_usermode_loop+0x103/0x110 > do_syscall_64+0x19d/0x1e0 > entry_SYSCALL_64_after_hwframe+0x44/0xa9 Fix this by tearing down the link from an stm device to its protocol driver when the policy involving that driver is removed. Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com> Fixes: c7fd62bc69d02 ("stm class: Introduce framing protocol drivers") Reported-by: Ammy Yi <ammy.yi@intel.com> Tested-by: Ammy Yi <ammy.yi@intel.com> CC: stable@vger.kernel.org # v4.20+ Link: https://lore.kernel.org/r/20191114064201.43089-2-alexander.shishkin@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* stm class: Fix a module refcount leak in policy creation error pathAlexander Shishkin2018-12-191-5/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit c7fd62bc69d0 ("stm class: Introduce framing protocol drivers") adds a bug into the error path of policy creation, that would do a module_put() on a wrong module, if one tried to create a policy for an stm device which already has a policy, using a different protocol. IOW, | mkdir /config/stp-policy/dummy_stm.0:p_basic.test | mkdir /config/stp-policy/dummy_stm.0:p_sys-t.test # puts "p_basic" | mkdir /config/stp-policy/dummy_stm.0:p_sys-t.test # "p_basic" -> -1 throws: | general protection fault: 0000 [#1] SMP PTI | CPU: 3 PID: 2887 Comm: mkdir | RIP: 0010:module_put.part.31+0xe/0x90 | Call Trace: | module_put+0x13/0x20 | stm_put_protocol+0x11/0x20 [stm_core] | stp_policy_make+0xf1/0x210 [stm_core] | ? __kmalloc+0x183/0x220 | ? configfs_mkdir+0x10d/0x4c0 | configfs_mkdir+0x169/0x4c0 | vfs_mkdir+0x108/0x1c0 | do_mkdirat+0xe8/0x110 | __x64_sys_mkdir+0x1b/0x20 | do_syscall_64+0x5a/0x140 | entry_SYSCALL_64_after_hwframe+0x44/0xa9 Correct this sad mistake by calling calling 'put' on the correct reference, which happens to match another error path in the same function, so we consolidate the two at the same time. Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com> Fixes: c7fd62bc69d0 ("stm class: Introduce framing protocol drivers") Reported-by: Ammy Yi <ammy.yi@intel.com> Cc: stable <stable@vger.kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* stm class: Use memcat_p()Alexander Shishkin2018-10-111-28/+1
| | | | | | | | | Instead of a local copy, use the memcat_p() helper to merge policy node attributes. Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com> Tested-by: Mathieu Poirier <mathieu.poirier@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* stm class: Switch over to the protocol driverAlexander Shishkin2018-10-111-2/+1
| | | | | | | | | | | | | | Now that the default framing protocol is factored out into its own driver, switch over to using the driver for writing data. To that end, make the policy code require a valid protocol name (or absence thereof, which is equivalent to "p_basic"). Also, to make transition easier, make stm class request "p_basic" module at initialization time. Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com> Tested-by: Mathieu Poirier <mathieu.poirier@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* stm class: Introduce framing protocol driversAlexander Shishkin2018-10-111-10/+135
| | | | | | | | | | | | At the moment, the stm class applies a certain STP framing pattern to the data as it is written to the underlying STM device. In order to allow different framing patterns (aka protocols), this patch introduces the concept of STP protocol drivers, defines data structures and APIs for the protocol drivers to use. Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com> Tested-by: Mathieu Poirier <mathieu.poirier@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* stm class: Clean up stp_configfs_initAlexander Shishkin2018-10-111-5/+1
| | | | | | | | Minor code shortening, no functional changes. Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com> Tested-by: Mathieu Poirier <mathieu.poirier@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* stm class: Clarify configfs root type/operations namesAlexander Shishkin2018-10-111-6/+6
| | | | | | | | | The current naming of stp-policy root type and group ops is confusing, rename them for better readability. Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com> Tested-by: Mathieu Poirier <mathieu.poirier@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* stm class: Rework policy node fallbackAlexander Shishkin2018-10-111-6/+6
| | | | | | | | | | | | | | | | | | | | | | | | | Currently, if no matching policy node can be found for a trace source, we'll try to use "default" policy node, then, if that doesn't exist, we'll pick the first node, in order of creation. If that also fails, we'll allocate M/C range from the beginning of the device's M/C range. This makes it difficult to know which node (if any) was used in any particular case. In order to make things more deterministic, the new order is as follows: * if they supply ID string, use that and nothing else, * if they are a task, use their task name (comm), * use "default", if it exists, * return failure, to let them know there is no suitable rule. This should provide enough convenience with the "default" catch-all node, while not leaving *everything* to chance. As a side effect, this relaxes the requirement of using ioctl() for identification with the possibility of using task names as policy nodes. Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com> Tested-by: Mathieu Poirier <mathieu.poirier@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* stm class: Add SPDX GPL-2.0 header to replace GPLv2 boilerplateAlexander Shishkin2018-03-281-9/+1
| | | | | | | This adds SPDX GPL-2.0 header to to stm core files and removes the GPLv2 boilerplate text. Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
* stm class: make config_item_type constBhumika Goyal2017-10-191-5/+5
| | | | | | | | | | | | Make config_item_type structures const as they are either passed to a function having the argument as const or used inside a if statement or stored in the const "ci_type" field of a config_item structure. Done using Coccinelle. Signed-off-by: Bhumika Goyal <bhumirks@gmail.com> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Christoph Hellwig <hch@lst.de>
* stm class: Remove unnecessary pointer incrementAlexander Shishkin2016-04-081-1/+1
| | | | | | | | | | Readability: a postfix increment is used on a pointer which is not used anywhere afterwards, which may send the reader looking through the function one extra time. Drop the unnecessary increment. Reported-by: Alan Cox <alan.cox@intel.com> Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com> Reviewed-by: Laurent Fert <laurent.fert@intel.com>
* stm class: Fix integer boundary checks for master rangeChunyan Zhang2016-04-081-2/+1
| | | | | | | | | | | | | | Master IDs are of unsigned int type, yet in the configfs policy code we're validating user's input against INT_MAX. This is both pointless and misleading as the real limits are imposed by the stm device's [sw_start..sw_end] (which are also limited by the spec to be no larger than 2^16-1). Clean this up by getting rid of the redundant comparisons. Signed-off-by: Chunyan Zhang <zhang.chunyan@linaro.org> Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com> Reviewed-by: Laurent Fert <laurent.fert@intel.com>
* stm class: Support devices with multiple instancesAlexander Shishkin2016-02-201-3/+4
| | | | | | | | | | | | | | | | | | By convention, the name of the stm policy directory in configfs consists of the device name to which it applies and the actual policy name, separated by a dot. Now, some devices already have dots in their names that separate name of the actual device from its instance identifier. Such devices will result in two (or more, who can tell) dots in the policy directory name. Existing policy code, however, will treat the first dot as the one that separates device name from policy name, therefore failing the above case. This patch makes the last dot in the directory name be the separator, thus prohibiting dots from being used in policy names. Suggested-by: Chunyan Zhang <zhang.chunyan@linaro.org> Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* stm class: Fix locking in unbinding policy pathAlexander Shishkin2016-02-071-3/+15
| | | | | | | | | | | | | | Right now, if stm device removal has to unbind from a policy (that is, an stm device that has STP policy, gets removed), it will trigger a nested lock on the stm device's policy mutex. This patch fixes the problem by moving the locking from the policy unbinding to policy removal (configfs path), where it's actually needed; the other caller of the policy unbinding function already takes the mutex around the call. Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Merge branch 'for-next' of ↵Linus Torvalds2015-11-131-81/+24
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending Pull SCSI target updates from Nicholas Bellinger: "This series contains HCH's changes to absorb configfs attribute ->show() + ->store() function pointer usage from it's original tree-wide consumers, into common configfs code. It includes usb-gadget, target w/ drivers, netconsole and ocfs2 changes to realize the improved simplicity, that now renders the original include/target/configfs_macros.h CPP magic for fabric drivers and others, unnecessary and obsolete. And with common code in place, new configfs attributes can be added easier than ever before. Note, there are further improvements in-flight from other folks for v4.5 code in configfs land, plus number of target fixes for post -rc1 code" In the meantime, a new user of the now-removed old configfs API came in through the char/misc tree in commit 7bd1d4093c2f ("stm class: Introduce an abstraction for System Trace Module devices"). This merge resolution comes from Alexander Shishkin, who updated his stm class tracing abstraction to account for the removal of the old show_attribute and store_attribute methods in commit 517982229f78 ("configfs: remove old API") from this pull. As Alexander says about that patch: "There's no need to keep an extra wrapper structure per item and the awkward show_attribute/store_attribute item ops are no longer needed. This patch converts policy code to the new api, all the while making the code quite a bit smaller and easier on the eyes. Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>" That patch was folded into the merge so that the tree should be fully bisectable. * 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending: (23 commits) configfs: remove old API ocfs2/cluster: use per-attribute show and store methods ocfs2/cluster: move locking into attribute store methods netconsole: use per-attribute show and store methods target: use per-attribute show and store methods spear13xx_pcie_gadget: use per-attribute show and store methods dlm: use per-attribute show and store methods usb-gadget/f_serial: use per-attribute show and store methods usb-gadget/f_phonet: use per-attribute show and store methods usb-gadget/f_obex: use per-attribute show and store methods usb-gadget/f_uac2: use per-attribute show and store methods usb-gadget/f_uac1: use per-attribute show and store methods usb-gadget/f_mass_storage: use per-attribute show and store methods usb-gadget/f_sourcesink: use per-attribute show and store methods usb-gadget/f_printer: use per-attribute show and store methods usb-gadget/f_midi: use per-attribute show and store methods usb-gadget/f_loopback: use per-attribute show and store methods usb-gadget/ether: use per-attribute show and store methods usb-gadget/f_acm: use per-attribute show and store methods usb-gadget/f_hid: use per-attribute show and store methods ...
* stm class: Introduce an abstraction for System Trace Module devicesAlexander Shishkin2015-10-041-0/+529
A System Trace Module (STM) is a device exporting data in System Trace Protocol (STP) format as defined by MIPI STP standards. Examples of such devices are Intel(R) Trace Hub and Coresight STM. This abstraction provides a unified interface for software trace sources to send their data over an STM device to a debug host. In order to do that, such a trace source needs to be assigned a pair of master/channel identifiers that all the data from this source will be tagged with. The STP decoder on the debug host side will use these master/channel tags to distinguish different trace streams from one another inside one STP stream. This abstraction provides a configfs-based policy management mechanism for dynamic allocation of these master/channel pairs based on trace source-supplied string identifier. It has the flexibility of being defined at runtime and at the same time (provided that the policy definition is aligned with the decoding end) consistency. For userspace trace sources, this abstraction provides write()-based and mmap()-based (if the underlying stm device allows this) output mechanism. For kernel-side trace sources, we provide "stm_source" device class that can be connected to an stm device at run time. Cc: linux-api@vger.kernel.org Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org> Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>