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path: root/drivers/firmware/arm_scmi/shmem.c
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2023-01-03firmware: arm_scmi: Harden shared memory access in fetch_notificationCristian Marussi
A misbheaving SCMI platform firmware could reply with out-of-spec notifications, shorter than the mimimum size comprising a header. Fixes: d5141f37c42e ("firmware: arm_scmi: Add notifications support in transport layer") Signed-off-by: Cristian Marussi <cristian.marussi@arm.com> Link: https://lore.kernel.org/r/20221222183823.518856-4-cristian.marussi@arm.com Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
2023-01-03firmware: arm_scmi: Harden shared memory access in fetch_responseCristian Marussi
A misbheaving SCMI platform firmware could reply with out-of-spec messages, shorter than the mimimum size comprising a header and a status field. Harden shmem_fetch_response to properly truncate such a bad messages. Fixes: 5c8a47a5a91d ("firmware: arm_scmi: Make scmi core independent of the transport type") Signed-off-by: Cristian Marussi <cristian.marussi@arm.com> Link: https://lore.kernel.org/r/20221222183823.518856-3-cristian.marussi@arm.com Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
2022-11-01firmware: arm_scmi: Make tx_prepare time out eventuallyCristian Marussi
SCMI transports based on shared memory, at start of transmissions, have to wait for the shared Tx channel area to be eventually freed by the SCMI platform before accessing the channel. In fact the channel is owned by the SCMI platform until marked as free by the platform itself and, as such, cannot be used by the agent until relinquished. As a consequence a badly misbehaving SCMI platform firmware could lock the channel indefinitely and make the kernel side SCMI stack loop forever waiting for such channel to be freed, possibly hanging the whole boot sequence. Add a timeout to the existent Tx waiting spin-loop so that, when the system ends up in this situation, the SCMI stack can at least bail-out, nosily warn the user, and abort the transmission. Reported-by: YaxiongTian <iambestgod@outlook.com> Suggested-by: YaxiongTian <iambestgod@outlook.com> Cc: Vincent Guittot <vincent.guittot@linaro.org> Cc: Etienne Carriere <etienne.carriere@linaro.org> Cc: Florian Fainelli <f.fainelli@gmail.com> Signed-off-by: Cristian Marussi <cristian.marussi@arm.com> Link: https://lore.kernel.org/r/20221028140833.280091-3-cristian.marussi@arm.com Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
2020-04-20firmware: arm_scmi: Rename .clear_notification() transport_opsCristian Marussi
SCMI transport operation .clear_notification() is indeed a generic method to clear the channel in a transport dependent way, as such it could be a useful helper also in other contexts. Rename such method as .clear_channel(), renaming accordingly also its already existent call-sites. No functional change. Link: https://lore.kernel.org/r/20200420152315.21008-2-cristian.marussi@arm.com Signed-off-by: Cristian Marussi <cristian.marussi@arm.com> Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
2020-04-14firmware: arm_scmi: Add notifications support in transport layerCristian Marussi
Add common transport-layer methods to: - fetch a notification instead of a response - clear a pending notification Add also all the needed support in mailbox/shmem transports. Link: https://lore.kernel.org/r/20200327143438.5382-4-cristian.marussi@arm.com Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Reviewed-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Cristian Marussi <cristian.marussi@arm.com> Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
2020-02-20firmware: arm_scmi: Replace zero-length array with flexible-array memberGustavo A. R. Silva
The current codebase makes use of the zero-length array language extension to the C90 standard, but the preferred mechanism to declare variable-length types such as these ones is a flexible array member[1][2], introduced in C99: struct foo { int stuff; struct boo array[]; }; By making use of the mechanism above, we will get a compiler warning in case the flexible array does not occur last in the structure, which will help us prevent some kind of undefined behavior bugs from being inadvertenly introduced[3] to the codebase from now on. This issue was found with the help of Coccinelle. [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html [2] https://github.com/KSPP/linux/issues/21 [3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour") Replace the zero-length member "msg_payload" in scmi_shared_mem structure with flexible-array. Link: https://lore.kernel.org/r/20200211231045.GA13956@embeddedor Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com> [ rebased the change as files are moved around ] Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
2020-02-10firmware: arm_scmi: Make scmi core independent of the transport typeViresh Kumar
The SCMI specification is fairly independent of the transport protocol, which can be a simple mailbox (already implemented) or anything else. The current Linux implementation however is very much dependent on the mailbox transport layer. This patch makes the SCMI core code (driver.c) independent of the mailbox transport layer and moves all mailbox related code to a new file: mailbox.c and all struct shared_mem related code to a new file: shmem.c. We can now implement more transport protocols to transport SCMI messages. The transport protocols just need to provide struct scmi_transport_ops, with its version of the callbacks to enable exchange of SCMI messages. Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Link: https://lore.kernel.org/r/8698a3cec199b8feab35c2339f02dc232bfd773b.1580448239.git.viresh.kumar@linaro.org Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>