diff options
Diffstat (limited to 'Documentation')
47 files changed, 1297 insertions, 378 deletions
diff --git a/Documentation/00-INDEX b/Documentation/00-INDEX index 793acf999e9e..ed3e5e949fce 100644 --- a/Documentation/00-INDEX +++ b/Documentation/00-INDEX @@ -412,6 +412,8 @@ sysctl/ - directory with info on the /proc/sys/* files. target/ - directory with info on generating TCM v4 fabric .ko modules +tee.txt + - info on the TEE subsystem and drivers this_cpu_ops.txt - List rationale behind and the way to use this_cpu operations. thermal/ diff --git a/Documentation/RCU/00-INDEX b/Documentation/RCU/00-INDEX index f773a264ae02..1672573b037a 100644 --- a/Documentation/RCU/00-INDEX +++ b/Documentation/RCU/00-INDEX @@ -17,7 +17,7 @@ rcu_dereference.txt rcubarrier.txt - RCU and Unloadable Modules rculist_nulls.txt - - RCU list primitives for use with SLAB_DESTROY_BY_RCU + - RCU list primitives for use with SLAB_TYPESAFE_BY_RCU rcuref.txt - Reference-count design for elements of lists/arrays protected by RCU rcu.txt diff --git a/Documentation/RCU/Design/Data-Structures/Data-Structures.html b/Documentation/RCU/Design/Data-Structures/Data-Structures.html index d583c653a703..38d6d800761f 100644 --- a/Documentation/RCU/Design/Data-Structures/Data-Structures.html +++ b/Documentation/RCU/Design/Data-Structures/Data-Structures.html @@ -19,6 +19,8 @@ to each other. The <tt>rcu_state</tt> Structure</a> <li> <a href="#The rcu_node Structure"> The <tt>rcu_node</tt> Structure</a> +<li> <a href="#The rcu_segcblist Structure"> + The <tt>rcu_segcblist</tt> Structure</a> <li> <a href="#The rcu_data Structure"> The <tt>rcu_data</tt> Structure</a> <li> <a href="#The rcu_dynticks Structure"> @@ -841,6 +843,134 @@ for lockdep lock-class names. Finally, lines 64-66 produce an error if the maximum number of CPUs is too large for the specified fanout. +<h3><a name="The rcu_segcblist Structure"> +The <tt>rcu_segcblist</tt> Structure</a></h3> + +The <tt>rcu_segcblist</tt> structure maintains a segmented list of +callbacks as follows: + +<pre> + 1 #define RCU_DONE_TAIL 0 + 2 #define RCU_WAIT_TAIL 1 + 3 #define RCU_NEXT_READY_TAIL 2 + 4 #define RCU_NEXT_TAIL 3 + 5 #define RCU_CBLIST_NSEGS 4 + 6 + 7 struct rcu_segcblist { + 8 struct rcu_head *head; + 9 struct rcu_head **tails[RCU_CBLIST_NSEGS]; +10 unsigned long gp_seq[RCU_CBLIST_NSEGS]; +11 long len; +12 long len_lazy; +13 }; +</pre> + +<p> +The segments are as follows: + +<ol> +<li> <tt>RCU_DONE_TAIL</tt>: Callbacks whose grace periods have elapsed. + These callbacks are ready to be invoked. +<li> <tt>RCU_WAIT_TAIL</tt>: Callbacks that are waiting for the + current grace period. + Note that different CPUs can have different ideas about which + grace period is current, hence the <tt>->gp_seq</tt> field. +<li> <tt>RCU_NEXT_READY_TAIL</tt>: Callbacks waiting for the next + grace period to start. +<li> <tt>RCU_NEXT_TAIL</tt>: Callbacks that have not yet been + associated with a grace period. +</ol> + +<p> +The <tt>->head</tt> pointer references the first callback or +is <tt>NULL</tt> if the list contains no callbacks (which is +<i>not</i> the same as being empty). +Each element of the <tt>->tails[]</tt> array references the +<tt>->next</tt> pointer of the last callback in the corresponding +segment of the list, or the list's <tt>->head</tt> pointer if +that segment and all previous segments are empty. +If the corresponding segment is empty but some previous segment is +not empty, then the array element is identical to its predecessor. +Older callbacks are closer to the head of the list, and new callbacks +are added at the tail. +This relationship between the <tt>->head</tt> pointer, the +<tt>->tails[]</tt> array, and the callbacks is shown in this +diagram: + +</p><p><img src="nxtlist.svg" alt="nxtlist.svg" width="40%"> + +</p><p>In this figure, the <tt>->head</tt> pointer references the +first +RCU callback in the list. +The <tt>->tails[RCU_DONE_TAIL]</tt> array element references +the <tt>->head</tt> pointer itself, indicating that none +of the callbacks is ready to invoke. +The <tt>->tails[RCU_WAIT_TAIL]</tt> array element references callback +CB 2's <tt>->next</tt> pointer, which indicates that +CB 1 and CB 2 are both waiting on the current grace period, +give or take possible disagreements about exactly which grace period +is the current one. +The <tt>->tails[RCU_NEXT_READY_TAIL]</tt> array element +references the same RCU callback that <tt>->tails[RCU_WAIT_TAIL]</tt> +does, which indicates that there are no callbacks waiting on the next +RCU grace period. +The <tt>->tails[RCU_NEXT_TAIL]</tt> array element references +CB 4's <tt>->next</tt> pointer, indicating that all the +remaining RCU callbacks have not yet been assigned to an RCU grace +period. +Note that the <tt>->tails[RCU_NEXT_TAIL]</tt> array element +always references the last RCU callback's <tt>->next</tt> pointer +unless the callback list is empty, in which case it references +the <tt>->head</tt> pointer. + +<p> +There is one additional important special case for the +<tt>->tails[RCU_NEXT_TAIL]</tt> array element: It can be <tt>NULL</tt> +when this list is <i>disabled</i>. +Lists are disabled when the corresponding CPU is offline or when +the corresponding CPU's callbacks are offloaded to a kthread, +both of which are described elsewhere. + +</p><p>CPUs advance their callbacks from the +<tt>RCU_NEXT_TAIL</tt> to the <tt>RCU_NEXT_READY_TAIL</tt> to the +<tt>RCU_WAIT_TAIL</tt> to the <tt>RCU_DONE_TAIL</tt> list segments +as grace periods advance. + +</p><p>The <tt>->gp_seq[]</tt> array records grace-period +numbers corresponding to the list segments. +This is what allows different CPUs to have different ideas as to +which is the current grace period while still avoiding premature +invocation of their callbacks. +In particular, this allows CPUs that go idle for extended periods +to determine which of their callbacks are ready to be invoked after +reawakening. + +</p><p>The <tt>->len</tt> counter contains the number of +callbacks in <tt>->head</tt>, and the +<tt>->len_lazy</tt> contains the number of those callbacks that +are known to only free memory, and whose invocation can therefore +be safely deferred. + +<p><b>Important note</b>: It is the <tt>->len</tt> field that +determines whether or not there are callbacks associated with +this <tt>rcu_segcblist</tt> structure, <i>not</i> the <tt>->head</tt> +pointer. +The reason for this is that all the ready-to-invoke callbacks +(that is, those in the <tt>RCU_DONE_TAIL</tt> segment) are extracted +all at once at callback-invocation time. +If callback invocation must be postponed, for example, because a +high-priority process just woke up on this CPU, then the remaining +callbacks are placed back on the <tt>RCU_DONE_TAIL</tt> segment. +Either way, the <tt>->len</tt> and <tt>->len_lazy</tt> counts +are adjusted after the corresponding callbacks have been invoked, and so +again it is the <tt>->len</tt> count that accurately reflects whether +or not there are callbacks associated with this <tt>rcu_segcblist</tt> +structure. +Of course, off-CPU sampling of the <tt>->len</tt> count requires +the use of appropriate synchronization, for example, memory barriers. +This synchronization can be a bit subtle, particularly in the case +of <tt>rcu_barrier()</tt>. + <h3><a name="The rcu_data Structure"> The <tt>rcu_data</tt> Structure</a></h3> @@ -983,62 +1113,18 @@ choice. as follows: <pre> - 1 struct rcu_head *nxtlist; - 2 struct rcu_head **nxttail[RCU_NEXT_SIZE]; - 3 unsigned long nxtcompleted[RCU_NEXT_SIZE]; - 4 long qlen_lazy; - 5 long qlen; - 6 long qlen_last_fqs_check; + 1 struct rcu_segcblist cblist; + 2 long qlen_last_fqs_check; + 3 unsigned long n_cbs_invoked; + 4 unsigned long n_nocbs_invoked; + 5 unsigned long n_cbs_orphaned; + 6 unsigned long n_cbs_adopted; 7 unsigned long n_force_qs_snap; - 8 unsigned long n_cbs_invoked; - 9 unsigned long n_cbs_orphaned; -10 unsigned long n_cbs_adopted; -11 long blimit; + 8 long blimit; </pre> -<p>The <tt>->nxtlist</tt> pointer and the -<tt>->nxttail[]</tt> array form a four-segment list with -older callbacks near the head and newer ones near the tail. -Each segment contains callbacks with the corresponding relationship -to the current grace period. -The pointer out of the end of each of the four segments is referenced -by the element of the <tt>->nxttail[]</tt> array indexed by -<tt>RCU_DONE_TAIL</tt> (for callbacks handled by a prior grace period), -<tt>RCU_WAIT_TAIL</tt> (for callbacks waiting on the current grace period), -<tt>RCU_NEXT_READY_TAIL</tt> (for callbacks that will wait on the next -grace period), and -<tt>RCU_NEXT_TAIL</tt> (for callbacks that are not yet associated -with a specific grace period) -respectively, as shown in the following figure. - -</p><p><img src="nxtlist.svg" alt="nxtlist.svg" width="40%"> - -</p><p>In this figure, the <tt>->nxtlist</tt> pointer references the -first -RCU callback in the list. -The <tt>->nxttail[RCU_DONE_TAIL]</tt> array element references -the <tt>->nxtlist</tt> pointer itself, indicating that none -of the callbacks is ready to invoke. -The <tt>->nxttail[RCU_WAIT_TAIL]</tt> array element references callback -CB 2's <tt>->next</tt> pointer, which indicates that -CB 1 and CB 2 are both waiting on the current grace period. -The <tt>->nxttail[RCU_NEXT_READY_TAIL]</tt> array element -references the same RCU callback that <tt>->nxttail[RCU_WAIT_TAIL]</tt> -does, which indicates that there are no callbacks waiting on the next -RCU grace period. -The <tt>->nxttail[RCU_NEXT_TAIL]</tt> array element references -CB 4's <tt>->next</tt> pointer, indicating that all the -remaining RCU callbacks have not yet been assigned to an RCU grace -period. -Note that the <tt>->nxttail[RCU_NEXT_TAIL]</tt> array element -always references the last RCU callback's <tt>->next</tt> pointer -unless the callback list is empty, in which case it references -the <tt>->nxtlist</tt> pointer. - -</p><p>CPUs advance their callbacks from the -<tt>RCU_NEXT_TAIL</tt> to the <tt>RCU_NEXT_READY_TAIL</tt> to the -<tt>RCU_WAIT_TAIL</tt> to the <tt>RCU_DONE_TAIL</tt> list segments -as grace periods advance. +<p>The <tt>->cblist</tt> structure is the segmented callback list +described earlier. The CPU advances the callbacks in its <tt>rcu_data</tt> structure whenever it notices that another RCU grace period has completed. The CPU detects the completion of an RCU grace period by noticing @@ -1049,16 +1135,7 @@ Recall that each <tt>rcu_node</tt> structure's <tt>->completed</tt> field is updated at the end of each grace period. -</p><p>The <tt>->nxtcompleted[]</tt> array records grace-period -numbers corresponding to the list segments. -This allows CPUs that go idle for extended periods to determine -which of their callbacks are ready to be invoked after reawakening. - -</p><p>The <tt>->qlen</tt> counter contains the number of -callbacks in <tt>->nxtlist</tt>, and the -<tt>->qlen_lazy</tt> contains the number of those callbacks that -are known to only free memory, and whose invocation can therefore -be safely deferred. +<p> The <tt>->qlen_last_fqs_check</tt> and <tt>->n_force_qs_snap</tt> coordinate the forcing of quiescent states from <tt>call_rcu()</tt> and friends when callback @@ -1069,6 +1146,10 @@ lists grow excessively long. fields count the number of callbacks invoked, sent to other CPUs when this CPU goes offline, and received from other CPUs when those other CPUs go offline. +The <tt>->n_nocbs_invoked</tt> is used when the CPU's callbacks +are offloaded to a kthread. + +<p> Finally, the <tt>->blimit</tt> counter is the maximum number of RCU callbacks that may be invoked at a given time. @@ -1104,6 +1185,9 @@ Its fields are as follows: 1 int dynticks_nesting; 2 int dynticks_nmi_nesting; 3 atomic_t dynticks; + 4 bool rcu_need_heavy_qs; + 5 unsigned long rcu_qs_ctr; + 6 bool rcu_urgent_qs; </pre> <p>The <tt>->dynticks_nesting</tt> field counts the @@ -1117,11 +1201,32 @@ NMIs are counted by the <tt>->dynticks_nmi_nesting</tt> field, except that NMIs that interrupt non-dyntick-idle execution are not counted. -</p><p>Finally, the <tt>->dynticks</tt> field counts the corresponding +</p><p>The <tt>->dynticks</tt> field counts the corresponding CPU's transitions to and from dyntick-idle mode, so that this counter has an even value when the CPU is in dyntick-idle mode and an odd value otherwise. +</p><p>The <tt>->rcu_need_heavy_qs</tt> field is used +to record the fact that the RCU core code would really like to +see a quiescent state from the corresponding CPU, so much so that +it is willing to call for heavy-weight dyntick-counter operations. +This flag is checked by RCU's context-switch and <tt>cond_resched()</tt> +code, which provide a momentary idle sojourn in response. + +</p><p>The <tt>->rcu_qs_ctr</tt> field is used to record +quiescent states from <tt>cond_resched()</tt>. +Because <tt>cond_resched()</tt> can execute quite frequently, this +must be quite lightweight, as in a non-atomic increment of this +per-CPU field. + +</p><p>Finally, the <tt>->rcu_urgent_qs</tt> field is used to record +the fact that the RCU core code would really like to see a quiescent +state from the corresponding CPU, with the various other fields indicating +just how badly RCU wants this quiescent state. +This flag is checked by RCU's context-switch and <tt>cond_resched()</tt> +code, which, if nothing else, non-atomically increment <tt>->rcu_qs_ctr</tt> +in response. + <table> <tr><th> </th></tr> <tr><th align="left">Quick Quiz:</th></tr> diff --git a/Documentation/RCU/Design/Data-Structures/nxtlist.svg b/Documentation/RCU/Design/Data-Structures/nxtlist.svg index abc4cc73a097..0223e79c38e0 100644 --- a/Documentation/RCU/Design/Data-Structures/nxtlist.svg +++ b/Documentation/RCU/Design/Data-Structures/nxtlist.svg @@ -19,7 +19,7 @@ id="svg2" version="1.1" inkscape:version="0.48.4 r9939" - sodipodi:docname="nxtlist.fig"> + sodipodi:docname="segcblist.svg"> <metadata id="metadata94"> <rdf:RDF> @@ -28,7 +28,7 @@ <dc:format>image/svg+xml</dc:format> <dc:type rdf:resource="http://purl.org/dc/dcmitype/StillImage" /> - <dc:title></dc:title> + <dc:title /> </cc:Work> </rdf:RDF> </metadata> @@ -241,61 +241,51 @@ xml:space="preserve" x="225" y="675" - fill="#000000" - font-family="Courier" font-style="normal" font-weight="bold" font-size="324" - text-anchor="start" - id="text64">nxtlist</text> + id="text64" + style="font-size:324px;font-style:normal;font-weight:bold;text-anchor:start;fill:#000000;font-family:Courier">->head</text> <!-- Text --> <text xml:space="preserve" x="225" y="1800" - fill="#000000" - font-family="Courier" font-style="normal" font-weight="bold" font-size="324" - text-anchor="start" - id="text66">nxttail[RCU_DONE_TAIL]</text> + id="text66" + style="font-size:324px;font-style:normal;font-weight:bold;text-anchor:start;fill:#000000;font-family:Courier">->tails[RCU_DONE_TAIL]</text> <!-- Text --> <text xml:space="preserve" x="225" y="2925" - fill="#000000" - font-family="Courier" font-style="normal" font-weight="bold" font-size="324" - text-anchor="start" - id="text68">nxttail[RCU_WAIT_TAIL]</text> + id="text68" + style="font-size:324px;font-style:normal;font-weight:bold;text-anchor:start;fill:#000000;font-family:Courier">->tails[RCU_WAIT_TAIL]</text> <!-- Text --> <text xml:space="preserve" x="225" y="4050" - fill="#000000" - font-family="Courier" font-style="normal" font-weight="bold" font-size="324" - text-anchor="start" - id="text70">nxttail[RCU_NEXT_READY_TAIL]</text> + id="text70" + style="font-size:324px;font-style:normal;font-weight:bold;text-anchor:start;fill:#000000;font-family:Courier">->tails[RCU_NEXT_READY_TAIL]</text> <!-- Text --> <text xml:space="preserve" x="225" y="5175" - fill="#000000" - font-family="Courier" font-style="normal" font-weight="bold" font-size="324" - text-anchor="start" - id="text72">nxttail[RCU_NEXT_TAIL]</text> + id="text72" + style="font-size:324px;font-style:normal;font-weight:bold;text-anchor:start;fill:#000000;font-family:Courier">->tails[RCU_NEXT_TAIL]</text> <!-- Text --> <text xml:space="preserve" diff --git a/Documentation/RCU/Design/Expedited-Grace-Periods/Expedited-Grace-Periods.html b/Documentation/RCU/Design/Expedited-Grace-Periods/Expedited-Grace-Periods.html index 7a3194c5559a..e5d0bbd0230b 100644 --- a/Documentation/RCU/Design/Expedited-Grace-Periods/Expedited-Grace-Periods.html +++ b/Documentation/RCU/Design/Expedited-Grace-Periods/Expedited-Grace-Periods.html @@ -284,6 +284,7 @@ Expedited Grace Period Refinements</a></h2> Funnel locking and wait/wakeup</a>. <li> <a href="#Use of Workqueues">Use of Workqueues</a>. <li> <a href="#Stall Warnings">Stall warnings</a>. +<li> <a href="#Mid-Boot Operation">Mid-boot operation</a>. </ol> <h3><a name="Idle-CPU Checks">Idle-CPU Checks</a></h3> @@ -524,7 +525,7 @@ their grace periods and carrying out their wakeups. In earlier implementations, the task requesting the expedited grace period also drove it to completion. This straightforward approach had the disadvantage of needing to -account for signals sent to user tasks, +account for POSIX signals sent to user tasks, so more recent implemementations use the Linux kernel's <a href="https://www.kernel.org/doc/Documentation/workqueue.txt">workqueues</a>. @@ -533,8 +534,8 @@ The requesting task still does counter snapshotting and funnel-lock processing, but the task reaching the top of the funnel lock does a <tt>schedule_work()</tt> (from <tt>_synchronize_rcu_expedited()</tt> so that a workqueue kthread does the actual grace-period processing. -Because workqueue kthreads do not accept signals, grace-period-wait -processing need not allow for signals. +Because workqueue kthreads do not accept POSIX signals, grace-period-wait +processing need not allow for POSIX signals. In addition, this approach allows wakeups for the previous expedited grace period to be overlapped with processing for the next expedited @@ -586,6 +587,46 @@ blocking the current grace period are printed. Each stall warning results in another pass through the loop, but the second and subsequent passes use longer stall times. +<h3><a name="Mid-Boot Operation">Mid-boot operation</a></h3> + +<p> +The use of workqueues has the advantage that the expedited +grace-period code need not worry about POSIX signals. +Unfortunately, it has the +corresponding disadvantage that workqueues cannot be used until +they are initialized, which does not happen until some time after +the scheduler spawns the first task. +Given that there are parts of the kernel that really do want to +execute grace periods during this mid-boot “dead zone”, +expedited grace periods must do something else during thie time. + +<p> +What they do is to fall back to the old practice of requiring that the +requesting task drive the expedited grace period, as was the case +before the use of workqueues. +However, the requesting task is only required to drive the grace period +during the mid-boot dead zone. +Before mid-boot, a synchronous grace period is a no-op. +Some time after mid-boot, workqueues are used. + +<p> +Non-expedited non-SRCU synchronous grace periods must also operate +normally during mid-boot. +This is handled by causing non-expedited grace periods to take the +expedited code path during mid-boot. + +<p> +The current code assumes that there are no POSIX signals during +the mid-boot dead zone. +However, if an overwhelming need for POSIX signals somehow arises, +appropriate adjustments can be made to the expedited stall-warning code. +One such adjustment would reinstate the pre-workqueue stall-warning +checks, but only during the mid-boot dead zone. + +<p> +With this refinement, synchronous grace periods can now be used from +task context pretty much any time during the life of the kernel. + <h3><a name="Summary"> Summary</a></h3> diff --git a/Documentation/RCU/Design/Requirements/Requirements.html b/Documentation/RCU/Design/Requirements/Requirements.html index 21593496aca6..f60adf112663 100644 --- a/Documentation/RCU/Design/Requirements/Requirements.html +++ b/Documentation/RCU/Design/Requirements/Requirements.html @@ -659,8 +659,9 @@ systems with more than one CPU: In other words, a given instance of <tt>synchronize_rcu()</tt> can avoid waiting on a given RCU read-side critical section only if it can prove that <tt>synchronize_rcu()</tt> started first. + </font> - <p> + <p><font color="ffffff"> A related question is “When <tt>rcu_read_lock()</tt> doesn't generate any code, why does it matter how it relates to a grace period?” @@ -675,8 +676,9 @@ systems with more than one CPU: within the critical section, in which case none of the accesses within the critical section may observe the effects of any access following the grace period. + </font> - <p> + <p><font color="ffffff"> As of late 2016, mathematical models of RCU take this viewpoint, for example, see slides 62 and 63 of the @@ -1616,8 +1618,8 @@ CPUs should at least make reasonable forward progress. In return for its shorter latencies, <tt>synchronize_rcu_expedited()</tt> is permitted to impose modest degradation of real-time latency on non-idle online CPUs. -That said, it will likely be necessary to take further steps to reduce this -degradation, hopefully to roughly that of a scheduling-clock interrupt. +Here, “modest” means roughly the same latency +degradation as a scheduling-clock interrupt. <p> There are a number of situations where even @@ -1913,12 +1915,9 @@ This requirement is another factor driving batching of grace periods, but it is also the driving force behind the checks for large numbers of queued RCU callbacks in the <tt>call_rcu()</tt> code path. Finally, high update rates should not delay RCU read-side critical -sections, although some read-side delays can occur when using +sections, although some small read-side delays can occur when using <tt>synchronize_rcu_expedited()</tt>, courtesy of this function's use -of <tt>try_stop_cpus()</tt>. -(In the future, <tt>synchronize_rcu_expedited()</tt> will be -converted to use lighter-weight inter-processor interrupts (IPIs), -but this will still disturb readers, though to a much smaller degree.) +of <tt>smp_call_function_single()</tt>. <p> Although all three of these corner cases were understood in the early @@ -2154,7 +2153,8 @@ as will <tt>rcu_assign_pointer()</tt>. <p> Although <tt>call_rcu()</tt> may be invoked at any time during boot, callbacks are not guaranteed to be invoked until after -the scheduler is fully up and running. +all of RCU's kthreads have been spawned, which occurs at +<tt>early_initcall()</tt> time. This delay in callback invocation is due to the fact that RCU does not invoke callbacks until it is fully initialized, and this full initialization cannot occur until after the scheduler has initialized itself to the @@ -2167,8 +2167,10 @@ on what operations those callbacks could invoke. Perhaps surprisingly, <tt>synchronize_rcu()</tt>, <a href="#Bottom-Half Flavor"><tt>synchronize_rcu_bh()</tt></a> (<a href="#Bottom-Half Flavor">discussed below</a>), -and -<a href="#Sched Flavor"><tt>synchronize_sched()</tt></a> +<a href="#Sched Flavor"><tt>synchronize_sched()</tt></a>, +<tt>synchronize_rcu_expedited()</tt>, +<tt>synchronize_rcu_bh_expedited()</tt>, and +<tt>synchronize_sched_expedited()</tt> will all operate normally during very early boot, the reason being that there is only one CPU and preemption is disabled. @@ -2178,45 +2180,59 @@ state and thus a grace period, so the early-boot implementation can be a no-op. <p> -Both <tt>synchronize_rcu_bh()</tt> and <tt>synchronize_sched()</tt> -continue to operate normally through the remainder of boot, courtesy -of the fact that preemption is disabled across their RCU read-side -critical sections and also courtesy of the fact that there is still -only one CPU. -However, once the scheduler starts initializing, preemption is enabled. -There is still only a single CPU, but the fact that preemption is enabled -means that the no-op implementation of <tt>synchronize_rcu()</tt> no -longer works in <tt>CONFIG_PREEMPT=y</tt> kernels. -Therefore, as soon as the scheduler starts initializing, the early-boot -fastpath is disabled. -This means that <tt>synchronize_rcu()</tt> switches to its runtime -mode of operation where it posts callbacks, which in turn means that -any call to <tt>synchronize_rcu()</tt> will block until the corresponding -callback is invoked. -Unfortunately, the callback cannot be invoked until RCU's runtime -grace-period machinery is up and running, which cannot happen until -the scheduler has initialized itself sufficiently to allow RCU's -kthreads to be spawned. -Therefore, invoking <tt>synchronize_rcu()</tt> during scheduler -initialization can result in deadlock. +However, once the scheduler has spawned its first kthread, this early +boot trick fails for <tt>synchronize_rcu()</tt> (as well as for +<tt>synchronize_rcu_expedited()</tt>) in <tt>CONFIG_PREEMPT=y</tt> +kernels. +The reason is that an RCU read-side critical section might be preempted, +which means that a subsequent <tt>synchronize_rcu()</tt> really does have +to wait for something, as opposed to simply returning immediately. +Unfortunately, <tt>synchronize_rcu()</tt> can't do this until all of +its kthreads are spawned, which doesn't happen until some time during +<tt>early_initcalls()</tt> time. +But this is no excuse: RCU is nevertheless required to correctly handle +synchronous grace periods during this time period. +Once all of its kthreads are up and running, RCU starts running +normally. <table> <tr><th> </th></tr> <tr><th align="left">Quick Quiz:</th></tr> <tr><td> - So what happens with <tt>synchronize_rcu()</tt> during - scheduler initialization for <tt>CONFIG_PREEMPT=n</tt> - kernels? + How can RCU possibly handle grace periods before all of its + kthreads have been spawned??? </td></tr> <tr><th align="left">Answer:</th></tr> <tr><td bgcolor="#ffffff"><font color="ffffff"> - In <tt>CONFIG_PREEMPT=n</tt> kernel, <tt>synchronize_rcu()</tt> - maps directly to <tt>synchronize_sched()</tt>. - Therefore, <tt>synchronize_rcu()</tt> works normally throughout - boot in <tt>CONFIG_PREEMPT=n</tt> kernels. - However, your code must also work in <tt>CONFIG_PREEMPT=y</tt> kernels, - so it is still necessary to avoid invoking <tt>synchronize_rcu()</tt> - during scheduler initialization. + Very carefully! + </font> + + <p><font color="ffffff"> + During the “dead zone” between the time that the + scheduler spawns the first task and the time that all of RCU's + kthreads have been spawned, all synchronous grace periods are + handled by the expedited grace-period mechanism. + At runtime, this expedited mechanism relies on workqueues, but + during the dead zone the requesting task itself drives the + desired expedited grace period. + Because dead-zone execution takes place within task context, + everything works. + Once the dead zone ends, expedited grace periods go back to + using workqueues, as is required to avoid problems that would + otherwise occur when a user task received a POSIX signal while + driving an expedited grace period. + </font> + + <p><font color="ffffff"> + And yes, this does mean that it is unhelpful to send POSIX + signals to random tasks between the time that the scheduler + spawns its first kthread and the time that RCU's kthreads + have all been spawned. + If there ever turns out to be a good reason for sending POSIX + signals during that time, appropriate adjustments will be made. + (If it turns out that POSIX signals are sent during this time for + no good reason, other adjustments will be made, appropriate + or otherwise.) </font></td></tr> <tr><td> </td></tr> </table> @@ -2295,12 +2311,61 @@ situation, and Dipankar Sarma incorporated <tt>rcu_barrier()</tt> into RCU. The need for <tt>rcu_barrier()</tt> for module unloading became apparent later. +<p> +<b>Important note</b>: The <tt>rcu_barrier()</tt> function is not, +repeat, <i>not</i>, obligated to wait for a grace period. +It is instead only required to wait for RCU callbacks that have +already been posted. +Therefore, if there are no RCU callbacks posted anywhere in the system, +<tt>rcu_barrier()</tt> is within its rights to return immediately. +Even if there are callbacks posted, <tt>rcu_barrier()</tt> does not +necessarily need to wait for a grace period. + +<table> +<tr><th> </th></tr> +<tr><th align="left">Quick Quiz:</th></tr> +<tr><td> + Wait a minute! + Each RCU callbacks must wait for a grace period to complete, + and <tt>rcu_barrier()</tt> must wait for each pre-existing + callback to be invoked. + Doesn't <tt>rcu_barrier()</tt> therefore need to wait for + a full grace period if there is even one callback posted anywhere + in the system? +</td></tr> +<tr><th align="left">Answer:</th></tr> +<tr><td bgcolor="#ffffff"><font color="ffffff"> + Absolutely not!!! + </font> + + <p><font color="ffffff"> + Yes, each RCU callbacks must wait for a grace period to complete, + but it might well be partly (or even completely) finished waiting + by the time <tt>rcu_barrier()</tt> is invoked. + In that case, <tt>rcu_barrier()</tt> need only wait for the + remaining portion of the grace period to elapse. + So even if there are quite a few callbacks posted, + <tt>rcu_barrier()</tt> might well return quite quickly. + </font> + + <p><font color="ffffff"> + So if you need to wait for a grace period as well as for all + pre-existing callbacks, you will need to invoke both + <tt>synchronize_rcu()</tt> and <tt>rcu_barrier()</tt>. + If latency is a concern, you can always use workqueues + to invoke them concurrently. +</font></td></tr> +<tr><td> </td></tr> +</table> + <h3><a name="Hotplug CPU">Hotplug CPU</a></h3> <p> The Linux kernel supports CPU hotplug, which means that CPUs can come and go. -It is of course illegal to use any RCU API member from an offline CPU. +It is of course illegal to use any RCU API member from an offline CPU, +with the exception of <a href="#Sleepable RCU">SRCU</a> read-side +critical sections. This requirement was present from day one in DYNIX/ptx, but on the other hand, the Linux kernel's CPU-hotplug implementation is “interesting.” @@ -2310,19 +2375,18 @@ The Linux-kernel CPU-hotplug implementation has notifiers that are used to allow the various kernel subsystems (including RCU) to respond appropriately to a given CPU-hotplug operation. Most RCU operations may be invoked from CPU-hotplug notifiers, -including even normal synchronous grace-period operations -such as <tt>synchronize_rcu()</tt>. -However, expedited grace-period operations such as -<tt>synchronize_rcu_expedited()</tt> are not supported, -due to the fact that current implementations block CPU-hotplug -operations, which could result in deadlock. +including even synchronous grace-period operations such as +<tt>synchronize_rcu()</tt> and <tt>synchronize_rcu_expedited()</tt>. <p> -In addition, all-callback-wait operations such as +However, all-callback-wait operations such as <tt>rcu_barrier()</tt> are also not supported, due to the fact that there are phases of CPU-hotplug operations where the outgoing CPU's callbacks will not be invoked until after the CPU-hotplug operation ends, which could also result in deadlock. +Furthermore, <tt>rcu_barrier()</tt> blocks CPU-hotplug operations +during its execution, which results in another type of deadlock +when invoked from a CPU-hotplug notifier. <h3><a name="Scheduler and RCU">Scheduler and RCU</a></h3> @@ -2864,6 +2928,27 @@ API, which, in combination with <tt>srcu_read_unlock()</tt>, guarantees a full memory barrier. <p> +Also unlike other RCU flavors, SRCU's callbacks-wait function +<tt>srcu_barrier()</tt> may be invoked from CPU-hotplug notifiers, +though this is not necessarily a good idea. +The reason that this is possible is that SRCU is insensitive +to whether or not a CPU is online, which means that <tt>srcu_barrier()</tt> +need not exclude CPU-hotplug operations. + +<p> +As of v4.12, SRCU's callbacks are maintained per-CPU, eliminating +a locking bottleneck present in prior kernel versions. +Although this will allow users to put much heavier stress on +<tt>call_srcu()</tt>, it is important to note that SRCU does not +yet take any special steps to deal with callback flooding. +So if you are posting (say) 10,000 SRCU callbacks per second per CPU, +you are probably totally OK, but if you intend to post (say) 1,000,000 +SRCU callbacks per second per CPU, please run some tests first. +SRCU just might need a few adjustment to deal with that sort of load. +Of course, your mileage may vary based on the speed of your CPUs and +the size of your memory. + +<p> The <a href="https://lwn.net/Articles/609973/#RCU Per-Flavor API Table">SRCU API</a> includes @@ -3021,8 +3106,8 @@ to do some redesign to avoid this scalability problem. <p> RCU disables CPU hotplug in a few places, perhaps most notably in the -expedited grace-period and <tt>rcu_barrier()</tt> operations. -If there is a strong reason to use expedited grace periods in CPU-hotplug +<tt>rcu_barrier()</tt> operations. +If there is a strong reason to use <tt>rcu_barrier()</tt> in CPU-hotplug notifiers, it will be necessary to avoid disabling CPU hotplug. This would introduce some complexity, so there had better be a <i>very</i> good reason. @@ -3096,9 +3181,5 @@ Andy Lutomirski for their help in rendering this article human readable, and to Michelle Rankin for her support of this effort. Other contributions are acknowledged in the Linux kernel's git archive. -The cartoon is copyright (c) 2013 by Melissa Broussard, -and is provided -under the terms of the Creative Commons Attribution-Share Alike 3.0 -United States license. </body></html> diff --git a/Documentation/RCU/rcu_dereference.txt b/Documentation/RCU/rcu_dereference.txt index c0bf2441a2ba..b2a613f16d74 100644 --- a/Documentation/RCU/rcu_dereference.txt +++ b/Documentation/RCU/rcu_dereference.txt @@ -138,6 +138,15 @@ o Be very careful about comparing pointers obtained from This sort of comparison occurs frequently when scanning RCU-protected circular linked lists. + Note that if checks for being within an RCU read-side + critical section are not required and the pointer is never + dereferenced, rcu_access_pointer() should be used in place + of rcu_dereference(). The rcu_access_pointer() primitive + does not require an enclosing read-side critical section, + and also omits the smp_read_barrier_depends() included in + rcu_dereference(), which in turn should provide a small + performance gain in some CPUs (e.g., the DEC Alpha). + o The comparison is against a pointer that references memory that was initialized "a long time ago." The reason this is safe is that even if misordering occurs, the diff --git a/Documentation/RCU/rculist_nulls.txt b/Documentation/RCU/rculist_nulls.txt index 18f9651ff23d..8151f0195f76 100644 --- a/Documentation/RCU/rculist_nulls.txt +++ b/Documentation/RCU/rculist_nulls.txt @@ -1,5 +1,5 @@ Using hlist_nulls to protect read-mostly linked lists and -objects using SLAB_DESTROY_BY_RCU allocations. +objects using SLAB_TYPESAFE_BY_RCU allocations. Please read the basics in Documentation/RCU/listRCU.txt @@ -7,7 +7,7 @@ Using special makers (called 'nulls') is a convenient way to solve following problem : A typical RCU linked list managing objects which are -allocated with SLAB_DESTROY_BY_RCU kmem_cache can +allocated with SLAB_TYPESAFE_BY_RCU kmem_cache can use following algos : 1) Lookup algo @@ -96,7 +96,7 @@ unlock_chain(); // typically a spin_unlock() 3) Remove algo -------------- Nothing special here, we can use a standard RCU hlist deletion. -But thanks to SLAB_DESTROY_BY_RCU, beware a deleted object can be reused +But thanks to SLAB_TYPESAFE_BY_RCU, beware a deleted object can be reused very very fast (before the end of RCU grace period) if (put_last_reference_on(obj) { diff --git a/Documentation/RCU/stallwarn.txt b/Documentation/RCU/stallwarn.txt index e93d04133fe7..96a3d81837e1 100644 --- a/Documentation/RCU/stallwarn.txt +++ b/Documentation/RCU/stallwarn.txt @@ -1,9 +1,102 @@ Using RCU's CPU Stall Detector -The rcu_cpu_stall_suppress module parameter enables RCU's CPU stall -detector, which detects conditions that unduly delay RCU grace periods. -This module parameter enables CPU stall detection by default, but -may be overridden via boot-time parameter or at runtime via sysfs. +This document first discusses what sorts of issues RCU's CPU stall +detector can locate, and then discusses kernel parameters and Kconfig +options that can be used to fine-tune the detector's operation. Finally, +this document explains the stall detector's "splat" format. + + +What Causes RCU CPU Stall Warnings? + +So your kernel printed an RCU CPU stall warning. The next question is +"What caused it?" The following problems can result in RCU CPU stall +warnings: + +o A CPU looping in an RCU read-side critical section. + +o A CPU looping with interrupts disabled. + +o A CPU looping with preemption disabled. This condition can + result in RCU-sched stalls and, if ksoftirqd is in use, RCU-bh + stalls. + +o A CPU looping with bottom halves disabled. This condition can + result in RCU-sched and RCU-bh stalls. + +o For !CONFIG_PREEMPT kernels, a CPU looping anywhere in the + kernel without invoking schedule(). Note that cond_resched() + does not necessarily prevent RCU CPU stall warnings. Therefore, + if the looping in the kernel is really expected and desirable + behavior, you might need to replace some of the cond_resched() + calls with calls to cond_resched_rcu_qs(). + +o Booting Linux using a console connection that is too slow to + keep up with the boot-time console-message rate. For example, + a 115Kbaud serial console can be -way- too slow to keep up + with boot-time message rates, and will frequently result in + RCU CPU stall warning messages. Especially if you have added + debug printk()s. + +o Anything that prevents RCU's grace-period kthreads from running. + This can result in the "All QSes seen" console-log message. + This message will include information on when the kthread last + ran and how often it should be expected to run. + +o A CPU-bound real-time task in a CONFIG_PREEMPT kernel, which might + happen to preempt a low-priority task in the middle of an RCU + read-side critical section. This is especially damaging if + that low-priority task is not permitted to run on any other CPU, + in which case the next RCU grace period can never complete, which + will eventually cause the system to run out of memory and hang. + While the system is in the process of running itself out of + memory, you might see stall-warning messages. + +o A CPU-bound real-time task in a CONFIG_PREEMPT_RT kernel that + is running at a higher priority than the RCU softirq threads. + This will prevent RCU callbacks from ever being invoked, + and in a CONFIG_PREEMPT_RCU kernel will further prevent + RCU grace periods from ever completing. Either way, the + system will eventually run out of memory and hang. In the + CONFIG_PREEMPT_RCU case, you might see stall-warning + messages. + +o A hardware or software issue shuts off the scheduler-clock + interrupt on a CPU that is not in dyntick-idle mode. This + problem really has happened, and seems to be most likely to + result in RCU CPU stall warnings for CONFIG_NO_HZ_COMMON=n kernels. + +o A bug in the RCU implementation. + +o A hardware failure. This is quite unlikely, but has occurred + at least once in real life. A CPU failed in a running system, + becoming unresponsive, but not causing an immediate crash. + This resulted in a series of RCU CPU stall warnings, eventually + leading the realization that the CPU had failed. + +The RCU, RCU-sched, RCU-bh, and RCU-tasks implementations have CPU stall +warning. Note that SRCU does -not- have CPU stall warnings. Please note +that RCU only detects CPU stalls when there is a grace period in progress. +No grace period, no CPU stall warnings. + +To diagnose the cause of the stall, inspect the stack traces. +The offending function will usually be near the top of the stack. +If you have a series of stall warnings from a single extended stall, +comparing the stack traces can often help determine where the stall +is occurring, which will usually be in the function nearest the top of +that portion of the stack which remains the same from trace to trace. +If you can reliably trigger the stall, ftrace can be quite helpful. + +RCU bugs can often be debugged with the help of CONFIG_RCU_TRACE +and with RCU's event tracing. For information on RCU's event tracing, +see include/trace/events/rcu.h. + + +Fine-Tuning the RCU CPU Stall Detector + +The rcuupdate.rcu_cpu_stall_suppress module parameter disables RCU's +CPU stall detector, which detects conditions that unduly delay RCU grace +periods. This module parameter enables CPU stall detection by default, +but may be overridden via boot-time parameter or at runtime via sysfs. The stall detector's idea of what constitutes "unduly delayed" is controlled by a set of kernel configuration variables and cpp macros: @@ -56,6 +149,9 @@ rcupdate.rcu_task_stall_timeout And continues with the output of sched_show_task() for each task stalling the current RCU-tasks grace period. + +Interpreting RCU's CPU Stall-Detector "Splats" + For non-RCU-tasks flavors of RCU, when a CPU detects that it is stalling, it will print a message similar to the following: @@ -178,89 +274,3 @@ grace period is in flight. It is entirely possible to see stall warnings from normal and from expedited grace periods at about the same time from the same run. - - -What Causes RCU CPU Stall Warnings? - -So your kernel printed an RCU CPU stall warning. The next question is -"What caused it?" The following problems can result in RCU CPU stall -warnings: - -o A CPU looping in an RCU read-side critical section. - -o A CPU looping with interrupts disabled. This condition can - result in RCU-sched and RCU-bh stalls. - -o A CPU looping with preemption disabled. This condition can - result in RCU-sched stalls and, if ksoftirqd is in use, RCU-bh - stalls. - -o A CPU looping with bottom halves disabled. This condition can - result in RCU-sched and RCU-bh stalls. - -o For !CONFIG_PREEMPT kernels, a CPU looping anywhere in the - kernel without invoking schedule(). Note that cond_resched() - does not necessarily prevent RCU CPU stall warnings. Therefore, - if the looping in the kernel is really expected and desirable - behavior, you might need to replace some of the cond_resched() - calls with calls to cond_resched_rcu_qs(). - -o Booting Linux using a console connection that is too slow to - keep up with the boot-time console-message rate. For example, - a 115Kbaud serial console can be -way- too slow to keep up - with boot-time message rates, and will frequently result in - RCU CPU stall warning messages. Especially if you have added - debug printk()s. - -o Anything that prevents RCU's grace-period kthreads from running. - This can result in the "All QSes seen" console-log message. - This message will include information on when the kthread last - ran and how often it should be expected to run. - -o A CPU-bound real-time task in a CONFIG_PREEMPT kernel, which might - happen to preempt a low-priority task in the middle of an RCU - read-side critical section. This is especially damaging if - that low-priority task is not permitted to run on any other CPU, - in which case the next RCU grace period can never complete, which - will eventually cause the system to run out of memory and hang. - While the system is in the process of running itself out of - memory, you might see stall-warning messages. - -o A CPU-bound real-time task in a CONFIG_PREEMPT_RT kernel that - is running at a higher priority than the RCU softirq threads. - This will prevent RCU callbacks from ever being invoked, - and in a CONFIG_PREEMPT_RCU kernel will further prevent - RCU grace periods from ever completing. Either way, the - system will eventually run out of memory and hang. In the - CONFIG_PREEMPT_RCU case, you might see stall-warning - messages. - -o A hardware or software issue shuts off the scheduler-clock - interrupt on a CPU that is not in dyntick-idle mode. This - problem really has happened, and seems to be most likely to - result in RCU CPU stall warnings for CONFIG_NO_HZ_COMMON=n kernels. - -o A bug in the RCU implementation. - -o A hardware failure. This is quite unlikely, but has occurred - at least once in real life. A CPU failed in a running system, - becoming unresponsive, but not causing an immediate crash. - This resulted in a series of RCU CPU stall warnings, eventually - leading the realization that the CPU had failed. - -The RCU, RCU-sched, RCU-bh, and RCU-tasks implementations have CPU stall -warning. Note that SRCU does -not- have CPU stall warnings. Please note -that RCU only detects CPU stalls when there is a grace period in progress. -No grace period, no CPU stall warnings. - -To diagnose the cause of the stall, inspect the stack traces. -The offending function will usually be near the top of the stack. -If you have a series of stall warnings from a single extended stall, -comparing the stack traces can often help determine where the stall -is occurring, which will usually be in the function nearest the top of -that portion of the stack which remains the same from trace to trace. -If you can reliably trigger the stall, ftrace can be quite helpful. - -RCU bugs can often be debugged with the help of CONFIG_RCU_TRACE -and with RCU's event tracing. For information on RCU's event tracing, -see include/trace/events/rcu.h. diff --git a/Documentation/RCU/whatisRCU.txt b/Documentation/RCU/whatisRCU.txt index 5cbd8b2395b8..8ed6c9f6133c 100644 --- a/Documentation/RCU/whatisRCU.txt +++ b/Documentation/RCU/whatisRCU.txt @@ -562,7 +562,9 @@ This section presents a "toy" RCU implementation that is based on familiar locking primitives. Its overhead makes it a non-starter for real-life use, as does its lack of scalability. It is also unsuitable for realtime use, since it allows scheduling latency to "bleed" from -one read-side critical section to another. +one read-side critical section to another. It also assumes recursive +reader-writer locks: If you try this with non-recursive locks, and +you allow nested rcu_read_lock() calls, you can deadlock. However, it is probably the easiest implementation to relate to, so is a good starting point. @@ -587,20 +589,21 @@ It is extremely simple: write_unlock(&rcu_gp_mutex); } -[You can ignore rcu_assign_pointer() and rcu_dereference() without -missing much. But here they are anyway. And whatever you do, don't -forget about them when submitting patches making use of RCU!] +[You can ignore rcu_assign_pointer() and rcu_dereference() without missing +much. But here are simplified versions anyway. And whatever you do, +don't forget about them when submitting patches making use of RCU!] - #define rcu_assign_pointer(p, v) ({ \ - smp_wmb(); \ - (p) = (v); \ - }) + #define rcu_assign_pointer(p, v) \ + ({ \ + smp_store_release(&(p), (v)); \ + }) - #define rcu_dereference(p) ({ \ - typeof(p) _________p1 = p; \ - smp_read_barrier_depends(); \ - (_________p1); \ - }) + #define rcu_dereference(p) \ + ({ \ + typeof(p) _________p1 = p; \ + smp_read_barrier_depends(); \ + (_________p1); \ + }) The rcu_read_lock() and rcu_read_unlock() primitive read-acquire @@ -925,7 +928,8 @@ d. Do you need RCU grace periods to complete even in the face e. Is your workload too update-intensive for normal use of RCU, but inappropriate for other synchronization mechanisms? - If so, consider SLAB_DESTROY_BY_RCU. But please be careful! + If so, consider SLAB_TYPESAFE_BY_RCU (which was originally + named SLAB_DESTROY_BY_RCU). But please be careful! f. Do you need read-side critical sections that are respected even though they are in the middle of the idle loop, during diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 230b03caee55..15f79c27748d 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -1578,6 +1578,15 @@ extended tables themselves, and also PASID support. With this option set, extended tables will not be used even on hardware which claims to support them. + tboot_noforce [Default Off] + Do not force the Intel IOMMU enabled under tboot. + By default, tboot will force Intel IOMMU on, which + could harm performance of some high-throughput + devices like 40GBit network cards, even if identity + mapping is enabled. + Note that using this option lowers the security + provided by tboot because it makes the system + vulnerable to DMA attacks. intel_idle.max_cstate= [KNL,HW,ACPI,X86] 0 disables intel_idle and fall back on acpi_idle. @@ -1644,6 +1653,12 @@ nobypass [PPC/POWERNV] Disable IOMMU bypass, using IOMMU for PCI devices. + iommu.passthrough= + [ARM64] Configure DMA to bypass the IOMMU by default. + Format: { "0" | "1" } + 0 - Use IOMMU translation for DMA. + 1 - Bypass the IOMMU for DMA. + unset - Use IOMMU translation for DMA. io7= [HW] IO7 for Marvel based alpha systems See comment before marvel_specify_io7 in @@ -2419,12 +2434,6 @@ and gids from such clients. This is intended to ease migration from NFSv2/v3. - objlayoutdriver.osd_login_prog= - [NFS] [OBJLAYOUT] sets the pathname to the program which - is used to automatically discover and login into new - osd-targets. Please see: - Documentation/filesystems/pnfs.txt for more explanations - nmi_debug= [KNL,SH] Specify one or more actions to take when a NMI is triggered. Format: [state][,regs][,debounce][,die] @@ -3785,6 +3794,14 @@ spia_pedr= spia_peddr= + srcutree.exp_holdoff [KNL] + Specifies how many nanoseconds must elapse + since the end of the last SRCU grace period for + a given srcu_struct until the next normal SRCU + grace period will be considered for automatic + expediting. Set to zero to disable automatic + expediting. + stacktrace [FTRACE] Enabled the stack tracer on boot up. diff --git a/Documentation/arm64/tagged-pointers.txt b/Documentation/arm64/tagged-pointers.txt index d9995f1f51b3..a25a99e82bb1 100644 --- a/Documentation/arm64/tagged-pointers.txt +++ b/Documentation/arm64/tagged-pointers.txt @@ -11,24 +11,56 @@ in AArch64 Linux. The kernel configures the translation tables so that translations made via TTBR0 (i.e. userspace mappings) have the top byte (bits 63:56) of the virtual address ignored by the translation hardware. This frees up -this byte for application use, with the following caveats: +this byte for application use. - (1) The kernel requires that all user addresses passed to EL1 - are tagged with tag 0x00. This means that any syscall - parameters containing user virtual addresses *must* have - their top byte cleared before trapping to the kernel. - (2) Non-zero tags are not preserved when delivering signals. - This means that signal handlers in applications making use - of tags cannot rely on the tag information for user virtual - addresses being maintained for fields inside siginfo_t. - One exception to this rule is for signals raised in response - to watchpoint debug exceptions, where the tag information - will be preserved. +Passing tagged addresses to the kernel +-------------------------------------- - (3) Special care should be taken when using tagged pointers, - since it is likely that C compilers will not hazard two - virtual addresses differing only in the upper byte. +All interpretation of userspace memory addresses by the kernel assumes +an address tag of 0x00. + +This includes, but is not limited to, addresses found in: + + - pointer arguments to system calls, including pointers in structures + passed to system calls, + + - the stack pointer (sp), e.g. when interpreting it to deliver a + signal, + + - the frame pointer (x29) and frame records, e.g. when interpreting + them to generate a backtrace or call graph. + +Using non-zero address tags in any of these locations may result in an +error code being returned, a (fatal) signal being raised, or other modes +of failure. + +For these reasons, passing non-zero address tags to the kernel via +system calls is forbidden, and using a non-zero address tag for sp is +strongly discouraged. + +Programs maintaining a frame pointer and frame records that use non-zero +address tags may suffer impaired or inaccurate debug and profiling +visibility. + + +Preserving tags +--------------- + +Non-zero tags are not preserved when delivering signals. This means that +signal handlers in applications making use of tags cannot rely on the +tag information for user virtual addresses being maintained for fields +inside siginfo_t. One exception to this rule is for signals raised in +response to watchpoint debug exceptions, where the tag information will +be preserved. The architecture prevents the use of a tagged PC, so the upper byte will be set to a sign-extension of bit 55 on exception return. + + +Other considerations +-------------------- + +Special care should be taken when using tagged pointers, since it is +likely that C compilers will not hazard two virtual addresses differing +only in the upper byte. diff --git a/Documentation/block/bfq-iosched.txt b/Documentation/block/bfq-iosched.txt index 1b87df6cd476..05e2822a80b3 100644 --- a/Documentation/block/bfq-iosched.txt +++ b/Documentation/block/bfq-iosched.txt @@ -11,6 +11,13 @@ controllers), BFQ's main features are: groups (switching back to time distribution when needed to keep throughput high). +In its default configuration, BFQ privileges latency over +throughput. So, when needed for achieving a lower latency, BFQ builds +schedules that may lead to a lower throughput. If your main or only +goal, for a given device, is to achieve the maximum-possible +throughput at all times, then do switch off all low-latency heuristics +for that device, by setting low_latency to 0. Full details in Section 3. + On average CPUs, the current version of BFQ can handle devices performing at most ~30K IOPS; at most ~50 KIOPS on faster CPUs. As a reference, 30-50 KIOPS correspond to very high bandwidths with @@ -375,11 +382,19 @@ default, low latency mode is enabled. If enabled, interactive and soft real-time applications are privileged and experience a lower latency, as explained in more detail in the description of how BFQ works. -DO NOT enable this mode if you need full control on bandwidth +DISABLE this mode if you need full control on bandwidth distribution. In fact, if it is enabled, then BFQ automatically increases the bandwidth share of privileged applications, as the main means to guarantee a lower latency to them. +In addition, as already highlighted at the beginning of this document, +DISABLE this mode if your only goal is to achieve a high throughput. +In fact, privileging the I/O of some application over the rest may +entail a lower throughput. To achieve the highest-possible throughput +on a non-rotational device, setting slice_idle to 0 may be needed too +(at the cost of giving up any strong guarantee on fairness and low +latency). + timeout_sync ------------ diff --git a/Documentation/devicetree/bindings/arm/firmware/linaro,optee-tz.txt b/Documentation/devicetree/bindings/arm/firmware/linaro,optee-tz.txt new file mode 100644 index 000000000000..d38834c67dff --- /dev/null +++ b/Documentation/devicetree/bindings/arm/firmware/linaro,optee-tz.txt @@ -0,0 +1,31 @@ +OP-TEE Device Tree Bindings + +OP-TEE is a piece of software using hardware features to provide a Trusted +Execution Environment. The security can be provided with ARM TrustZone, but +also by virtualization or a separate chip. + +We're using "linaro" as the first part of the compatible property for +the reference implementation maintained by Linaro. + +* OP-TEE based on ARM TrustZone required properties: + +- compatible : should contain "linaro,optee-tz" + +- method : The method of calling the OP-TEE Trusted OS. Permitted + values are: + + "smc" : SMC #0, with the register assignments specified + in drivers/tee/optee/optee_smc.h + + "hvc" : HVC #0, with the register assignments specified + in drivers/tee/optee/optee_smc.h + + + +Example: + firmware { + optee { + compatible = "linaro,optee-tz"; + method = "smc"; + }; + }; diff --git a/Documentation/devicetree/bindings/arm/mediatek/mediatek,apmixedsys.txt b/Documentation/devicetree/bindings/arm/mediatek/mediatek,apmixedsys.txt index cb0054ac7121..cd977db7630c 100644 --- a/Documentation/devicetree/bindings/arm/mediatek/mediatek,apmixedsys.txt +++ b/Documentation/devicetree/bindings/arm/mediatek/mediatek,apmixedsys.txt @@ -7,6 +7,7 @@ Required Properties: - compatible: Should be one of: - "mediatek,mt2701-apmixedsys" + - "mediatek,mt6797-apmixedsys" - "mediatek,mt8135-apmixedsys" - "mediatek,mt8173-apmixedsys" - #clock-cells: Must be 1 diff --git a/Documentation/devicetree/bindings/arm/mediatek/mediatek,imgsys.txt b/Documentation/devicetree/bindings/arm/mediatek/mediatek,imgsys.txt index f6a916686f4c..047b11ae5f45 100644 --- a/Documentation/devicetree/bindings/arm/mediatek/mediatek,imgsys.txt +++ b/Documentation/devicetree/bindings/arm/mediatek/mediatek,imgsys.txt @@ -7,6 +7,7 @@ Required Properties: - compatible: Should be one of: - "mediatek,mt2701-imgsys", "syscon" + - "mediatek,mt6797-imgsys", "syscon" - "mediatek,mt8173-imgsys", "syscon" - #clock-cells: Must be 1 diff --git a/Documentation/devicetree/bindings/arm/mediatek/mediatek,infracfg.txt b/Documentation/devicetree/bindings/arm/mediatek/mediatek,infracfg.txt index 1620ec2a5a3f..58d58e2006b8 100644 --- a/Documentation/devicetree/bindings/arm/mediatek/mediatek,infracfg.txt +++ b/Documentation/devicetree/bindings/arm/mediatek/mediatek,infracfg.txt @@ -8,6 +8,7 @@ Required Properties: - compatible: Should be one of: - "mediatek,mt2701-infracfg", "syscon" + - "mediatek,mt6797-infracfg", "syscon" - "mediatek,mt8135-infracfg", "syscon" - "mediatek,mt8173-infracfg", "syscon" - #clock-cells: Must be 1 diff --git a/Documentation/devicetree/bindings/arm/mediatek/mediatek,mmsys.txt b/Documentation/devicetree/bindings/arm/mediatek/mediatek,mmsys.txt index 67dd2e473d25..70529e0b58e9 100644 --- a/Documentation/devicetree/bindings/arm/mediatek/mediatek,mmsys.txt +++ b/Documentation/devicetree/bindings/arm/mediatek/mediatek,mmsys.txt @@ -7,6 +7,7 @@ Required Properties: - compatible: Should be one of: - "mediatek,mt2701-mmsys", "syscon" + - "mediatek,mt6797-mmsys", "syscon" - "mediatek,mt8173-mmsys", "syscon" - #clock-cells: Must be 1 diff --git a/Documentation/devicetree/bindings/arm/mediatek/mediatek,topckgen.txt b/Documentation/devicetree/bindings/arm/mediatek/mediatek,topckgen.txt index 9f2fe7860114..ec93ecbb9f3c 100644 --- a/Documentation/devicetree/bindings/arm/mediatek/mediatek,topckgen.txt +++ b/Documentation/devicetree/bindings/arm/mediatek/mediatek,topckgen.txt @@ -7,6 +7,7 @@ Required Properties: - compatible: Should be one of: - "mediatek,mt2701-topckgen" + - "mediatek,mt6797-topckgen" - "mediatek,mt8135-topckgen" - "mediatek,mt8173-topckgen" - #clock-cells: Must be 1 diff --git a/Documentation/devicetree/bindings/arm/mediatek/mediatek,vdecsys.txt b/Documentation/devicetree/bindings/arm/mediatek/mediatek,vdecsys.txt index 2440f73450c3..d150104f928a 100644 --- a/Documentation/devicetree/bindings/arm/mediatek/mediatek,vdecsys.txt +++ b/Documentation/devicetree/bindings/arm/mediatek/mediatek,vdecsys.txt @@ -7,6 +7,7 @@ Required Properties: - compatible: Should be one of: - "mediatek,mt2701-vdecsys", "syscon" + - "mediatek,mt6797-vdecsys", "syscon" - "mediatek,mt8173-vdecsys", "syscon" - #clock-cells: Must be 1 diff --git a/Documentation/devicetree/bindings/arm/mediatek/mediatek,vencsys.txt b/Documentation/devicetree/bindings/arm/mediatek/mediatek,vencsys.txt index 5bb2866a2b50..8a93be643647 100644 --- a/Documentation/devicetree/bindings/arm/mediatek/mediatek,vencsys.txt +++ b/Documentation/devicetree/bindings/arm/mediatek/mediatek,vencsys.txt @@ -5,7 +5,8 @@ The Mediatek vencsys controller provides various clocks to the system. Required Properties: -- compatible: Should be: +- compatible: Should be one of: + - "mediatek,mt6797-vencsys", "syscon" - "mediatek,mt8173-vencsys", "syscon" - #clock-cells: Must be 1 diff --git a/Documentation/devicetree/bindings/clock/idt,versaclock5.txt b/Documentation/devicetree/bindings/clock/idt,versaclock5.txt index 87e9c47a89a3..53d7e50ed875 100644 --- a/Documentation/devicetree/bindings/clock/idt,versaclock5.txt +++ b/Documentation/devicetree/bindings/clock/idt,versaclock5.txt @@ -6,18 +6,21 @@ from 3 to 12 output clocks. ==I2C device node== Required properties: -- compatible: shall be one of "idt,5p49v5923" , "idt,5p49v5933". +- compatible: shall be one of "idt,5p49v5923" , "idt,5p49v5933" , + "idt,5p49v5935". - reg: i2c device address, shall be 0x68 or 0x6a. - #clock-cells: from common clock binding; shall be set to 1. - clocks: from common clock binding; list of parent clock handles, - 5p49v5923: (required) either or both of XTAL or CLKIN reference clock. - - 5p49v5933: (optional) property not present (internal + - 5p49v5933 and + - 5p49v5935: (optional) property not present (internal Xtal used) or CLKIN reference clock. - clock-names: from common clock binding; clock input names, can be - 5p49v5923: (required) either or both of "xin", "clkin". - - 5p49v5933: (optional) property not present or "clkin". + - 5p49v5933 and + - 5p49v5935: (optional) property not present or "clkin". ==Mapping between clock specifier and physical pins== @@ -34,6 +37,13 @@ clock specifier, the following mapping applies: 1 -- OUT1 2 -- OUT4 +5P49V5935: + 0 -- OUT0_SEL_I2CB + 1 -- OUT1 + 2 -- OUT2 + 3 -- OUT3 + 4 -- OUT4 + ==Example== /* 25MHz reference crystal */ diff --git a/Documentation/devicetree/bindings/clock/rockchip,rk1108-cru.txt b/Documentation/devicetree/bindings/clock/rockchip,rv1108-cru.txt index 4da126116cf0..161326a4f9c1 100644 --- a/Documentation/devicetree/bindings/clock/rockchip,rk1108-cru.txt +++ b/Documentation/devicetree/bindings/clock/rockchip,rv1108-cru.txt @@ -1,12 +1,12 @@ -* Rockchip RK1108 Clock and Reset Unit +* Rockchip RV1108 Clock and Reset Unit -The RK1108 clock controller generates and supplies clock to various +The RV1108 clock controller generates and supplies clock to various controllers within the SoC and also implements a reset controller for SoC peripherals. Required Properties: -- compatible: should be "rockchip,rk1108-cru" +- compatible: should be "rockchip,rv1108-cru" - reg: physical base address of the controller and length of memory mapped region. - #clock-cells: should be 1. @@ -19,7 +19,7 @@ Optional Properties: Each clock is assigned an identifier and client nodes can use this identifier to specify the clock which they consume. All available clocks are defined as -preprocessor macros in the dt-bindings/clock/rk1108-cru.h headers and can be +preprocessor macros in the dt-bindings/clock/rv1108-cru.h headers and can be used in device tree sources. Similar macros exist for the reset sources in these files. @@ -38,7 +38,7 @@ clock-output-names: Example: Clock controller node: cru: cru@20200000 { - compatible = "rockchip,rk1108-cru"; + compatible = "rockchip,rv1108-cru"; reg = <0x20200000 0x1000>; rockchip,grf = <&grf>; @@ -50,7 +50,7 @@ Example: UART controller node that consumes the clock generated by the clock controller: uart0: serial@10230000 { - compatible = "rockchip,rk1108-uart", "snps,dw-apb-uart"; + compatible = "rockchip,rv1108-uart", "snps,dw-apb-uart"; reg = <0x10230000 0x100>; interrupts = <GIC_SPI 44 IRQ_TYPE_LEVEL_HIGH>; reg-shift = <2>; diff --git a/Documentation/devicetree/bindings/clock/sunxi-ccu.txt b/Documentation/devicetree/bindings/clock/sunxi-ccu.txt index bae5668cf427..e9c5a1d9834a 100644 --- a/Documentation/devicetree/bindings/clock/sunxi-ccu.txt +++ b/Documentation/devicetree/bindings/clock/sunxi-ccu.txt @@ -7,9 +7,12 @@ Required properties : - "allwinner,sun8i-a23-ccu" - "allwinner,sun8i-a33-ccu" - "allwinner,sun8i-h3-ccu" + - "allwinner,sun8i-h3-r-ccu" - "allwinner,sun8i-v3s-ccu" - "allwinner,sun9i-a80-ccu" - "allwinner,sun50i-a64-ccu" + - "allwinner,sun50i-a64-r-ccu" + - "allwinner,sun50i-h5-ccu" - reg: Must contain the registers base address and length - clocks: phandle to the oscillators feeding the CCU. Two are needed: @@ -19,7 +22,10 @@ Required properties : - #clock-cells : must contain 1 - #reset-cells : must contain 1 -Example: +For the PRCM CCUs on H3/A64, one more clock is needed: +- "iosc": the SoC's internal frequency oscillator + +Example for generic CCU: ccu: clock@01c20000 { compatible = "allwinner,sun8i-h3-ccu"; reg = <0x01c20000 0x400>; @@ -28,3 +34,13 @@ ccu: clock@01c20000 { #clock-cells = <1>; #reset-cells = <1>; }; + +Example for PRCM CCU: +r_ccu: clock@01f01400 { + compatible = "allwinner,sun50i-a64-r-ccu"; + reg = <0x01f01400 0x100>; + clocks = <&osc24M>, <&osc32k>, <&iosc>; + clock-names = "hosc", "losc", "iosc"; + #clock-cells = <1>; + #reset-cells = <1>; +}; diff --git a/Documentation/devicetree/bindings/display/imx/fsl,imx-fb.txt b/Documentation/devicetree/bindings/display/imx/fsl,imx-fb.txt index 7a5c0e204c8e..e5a8b363d829 100644 --- a/Documentation/devicetree/bindings/display/imx/fsl,imx-fb.txt +++ b/Documentation/devicetree/bindings/display/imx/fsl,imx-fb.txt @@ -13,6 +13,8 @@ Required nodes: Additional, the display node has to define properties: - bits-per-pixel: Bits per pixel - fsl,pcr: LCDC PCR value + A display node may optionally define + - fsl,aus-mode: boolean to enable AUS mode (only for imx21) Optional properties: - lcd-supply: Regulator for LCD supply voltage. diff --git a/Documentation/devicetree/bindings/iommu/arm,smmu.txt b/Documentation/devicetree/bindings/iommu/arm,smmu.txt index 6cdf32d037fc..8a6ffce12af5 100644 --- a/Documentation/devicetree/bindings/iommu/arm,smmu.txt +++ b/Documentation/devicetree/bindings/iommu/arm,smmu.txt @@ -60,6 +60,17 @@ conditions. aliases of secure registers have to be used during SMMU configuration. +- stream-match-mask : For SMMUs supporting stream matching and using + #iommu-cells = <1>, specifies a mask of bits to ignore + when matching stream IDs (e.g. this may be programmed + into the SMRn.MASK field of every stream match register + used). For cases where it is desirable to ignore some + portion of every Stream ID (e.g. for certain MMU-500 + configurations given globally unique input IDs). This + property is not valid for SMMUs using stream indexing, + or using stream matching with #iommu-cells = <2>, and + may be ignored if present in such cases. + ** Deprecated properties: - mmu-masters (deprecated in favour of the generic "iommus" binding) : @@ -109,3 +120,20 @@ conditions. master3 { iommus = <&smmu2 1 0x30>; }; + + + /* ARM MMU-500 with 10-bit stream ID input configuration */ + smmu3: iommu { + compatible = "arm,mmu-500", "arm,smmu-v2"; + ... + #iommu-cells = <1>; + /* always ignore appended 5-bit TBU number */ + stream-match-mask = 0x7c00; + }; + + bus { + /* bus whose child devices emit one unique 10-bit stream + ID each, but may master through multiple SMMU TBUs */ + iommu-map = <0 &smmu3 0 0x400>; + ... + }; diff --git a/Documentation/devicetree/bindings/mtd/atmel-nand.txt b/Documentation/devicetree/bindings/mtd/atmel-nand.txt index 3e7ee99d3949..f6bee57e453a 100644 --- a/Documentation/devicetree/bindings/mtd/atmel-nand.txt +++ b/Documentation/devicetree/bindings/mtd/atmel-nand.txt @@ -1,4 +1,109 @@ -Atmel NAND flash +Atmel NAND flash controller bindings + +The NAND flash controller node should be defined under the EBI bus (see +Documentation/devicetree/bindings/memory-controllers/atmel,ebi.txt). +One or several NAND devices can be defined under this NAND controller. +The NAND controller might be connected to an ECC engine. + +* NAND controller bindings: + +Required properties: +- compatible: should be one of the following + "atmel,at91rm9200-nand-controller" + "atmel,at91sam9260-nand-controller" + "atmel,at91sam9261-nand-controller" + "atmel,at91sam9g45-nand-controller" + "atmel,sama5d3-nand-controller" +- ranges: empty ranges property to forward EBI ranges definitions. +- #address-cells: should be set to 2. +- #size-cells: should be set to 1. +- atmel,nfc-io: phandle to the NFC IO block. Only required for sama5d3 + controllers. +- atmel,nfc-sram: phandle to the NFC SRAM block. Only required for sama5d3 + controllers. + +Optional properties: +- ecc-engine: phandle to the PMECC block. Only meaningful if the SoC embeds + a PMECC engine. + +* NAND device/chip bindings: + +Required properties: +- reg: describes the CS lines assigned to the NAND device. If the NAND device + exposes multiple CS lines (multi-dies chips), your reg property will + contain X tuples of 3 entries. + 1st entry: the CS line this NAND chip is connected to + 2nd entry: the base offset of the memory region assigned to this + device (always 0) + 3rd entry: the memory region size (always 0x800000) + +Optional properties: +- rb-gpios: the GPIO(s) used to check the Ready/Busy status of the NAND. +- cs-gpios: the GPIO(s) used to control the CS line. +- det-gpios: the GPIO used to detect if a Smartmedia Card is present. +- atmel,rb: an integer identifying the native Ready/Busy pin. Only meaningful + on sama5 SoCs. + +All generic properties described in +Documentation/devicetree/bindings/mtd/{common,nand}.txt also apply to the NAND +device node, and NAND partitions should be defined under the NAND node as +described in Documentation/devicetree/bindings/mtd/partition.txt. + +* ECC engine (PMECC) bindings: + +Required properties: +- compatible: should be one of the following + "atmel,at91sam9g45-pmecc" + "atmel,sama5d4-pmecc" + "atmel,sama5d2-pmecc" +- reg: should contain 2 register ranges. The first one is pointing to the PMECC + block, and the second one to the PMECC_ERRLOC block. + +Example: + + pmecc: ecc-engine@ffffc070 { + compatible = "atmel,at91sam9g45-pmecc"; + reg = <0xffffc070 0x490>, + <0xffffc500 0x100>; + }; + + ebi: ebi@10000000 { + compatible = "atmel,sama5d3-ebi"; + #address-cells = <2>; + #size-cells = <1>; + atmel,smc = <&hsmc>; + reg = <0x10000000 0x10000000 + 0x40000000 0x30000000>; + ranges = <0x0 0x0 0x10000000 0x10000000 + 0x1 0x0 0x40000000 0x10000000 + 0x2 0x0 0x50000000 0x10000000 + 0x3 0x0 0x60000000 0x10000000>; + clocks = <&mck>; + + nand_controller: nand-controller { + compatible = "atmel,sama5d3-nand-controller"; + atmel,nfc-sram = <&nfc_sram>; + atmel,nfc-io = <&nfc_io>; + ecc-engine = <&pmecc>; + #address-cells = <2>; + #size-cells = <1>; + ranges; + + nand@3 { + reg = <0x3 0x0 0x800000>; + atmel,rb = <0>; + + /* + * Put generic NAND/MTD properties and + * subnodes here. + */ + }; + }; + }; + +----------------------------------------------------------------------- + +Deprecated bindings (should not be used in new device trees): Required properties: - compatible: The possible values are: diff --git a/Documentation/devicetree/bindings/mtd/denali-nand.txt b/Documentation/devicetree/bindings/mtd/denali-nand.txt index b04d03a1d499..e593bbeb2115 100644 --- a/Documentation/devicetree/bindings/mtd/denali-nand.txt +++ b/Documentation/devicetree/bindings/mtd/denali-nand.txt @@ -1,11 +1,11 @@ * Denali NAND controller Required properties: - - compatible : should be "denali,denali-nand-dt" + - compatible : should be one of the following: + "altr,socfpga-denali-nand" - for Altera SOCFPGA - reg : should contain registers location and length for data and reg. - reg-names: Should contain the reg names "nand_data" and "denali_reg" - interrupts : The interrupt number. - - dm-mask : DMA bit mask The device tree may optionally contain sub-nodes describing partitions of the address space. See partition.txt for more detail. @@ -15,9 +15,8 @@ Examples: nand: nand@ff900000 { #address-cells = <1>; #size-cells = <1>; - compatible = "denali,denali-nand-dt"; + compatible = "altr,socfpga-denali-nand"; reg = <0xff900000 0x100000>, <0xffb80000 0x10000>; reg-names = "nand_data", "denali_reg"; interrupts = <0 144 4>; - dma-mask = <0xffffffff>; }; diff --git a/Documentation/devicetree/bindings/mtd/gpio-control-nand.txt b/Documentation/devicetree/bindings/mtd/gpio-control-nand.txt index af8915b41ccf..486a17d533d7 100644 --- a/Documentation/devicetree/bindings/mtd/gpio-control-nand.txt +++ b/Documentation/devicetree/bindings/mtd/gpio-control-nand.txt @@ -12,7 +12,7 @@ Required properties: - #address-cells, #size-cells : Must be present if the device has sub-nodes representing partitions. - gpios : Specifies the GPIO pins to control the NAND device. The order of - GPIO references is: RDY, nCE, ALE, CLE, and an optional nWP. + GPIO references is: RDY, nCE, ALE, CLE, and nWP. nCE and nWP are optional. Optional properties: - bank-width : Width (in bytes) of the device. If not present, the width @@ -36,7 +36,7 @@ gpio-nand@1,0 { #address-cells = <1>; #size-cells = <1>; gpios = <&banka 1 0>, /* RDY */ - <&banka 2 0>, /* nCE */ + <0>, /* nCE */ <&banka 3 0>, /* ALE */ <&banka 4 0>, /* CLE */ <0>; /* nWP */ diff --git a/Documentation/devicetree/bindings/mtd/stm32-quadspi.txt b/Documentation/devicetree/bindings/mtd/stm32-quadspi.txt new file mode 100644 index 000000000000..ddd18c135148 --- /dev/null +++ b/Documentation/devicetree/bindings/mtd/stm32-quadspi.txt @@ -0,0 +1,43 @@ +* STMicroelectronics Quad Serial Peripheral Interface(QuadSPI) + +Required properties: +- compatible: should be "st,stm32f469-qspi" +- reg: the first contains the register location and length. + the second contains the memory mapping address and length +- reg-names: should contain the reg names "qspi" "qspi_mm" +- interrupts: should contain the interrupt for the device +- clocks: the phandle of the clock needed by the QSPI controller +- A pinctrl must be defined to set pins in mode of operation for QSPI transfer + +Optional properties: +- resets: must contain the phandle to the reset controller. + +A spi flash must be a child of the nor_flash node and could have some +properties. Also see jedec,spi-nor.txt. + +Required properties: +- reg: chip-Select number (QSPI controller may connect 2 nor flashes) +- spi-max-frequency: max frequency of spi bus + +Optional property: +- spi-rx-bus-width: see ../spi/spi-bus.txt for the description + +Example: + +qspi: spi@a0001000 { + compatible = "st,stm32f469-qspi"; + reg = <0xa0001000 0x1000>, <0x90000000 0x10000000>; + reg-names = "qspi", "qspi_mm"; + interrupts = <91>; + resets = <&rcc STM32F4_AHB3_RESET(QSPI)>; + clocks = <&rcc 0 STM32F4_AHB3_CLOCK(QSPI)>; + pinctrl-names = "default"; + pinctrl-0 = <&pinctrl_qspi0>; + + flash@0 { + reg = <0>; + spi-rx-bus-width = <4>; + spi-max-frequency = <108000000>; + ... + }; +}; diff --git a/Documentation/devicetree/bindings/power/power_domain.txt b/Documentation/devicetree/bindings/power/power_domain.txt index 940707d095cc..14bd9e945ff6 100644 --- a/Documentation/devicetree/bindings/power/power_domain.txt +++ b/Documentation/devicetree/bindings/power/power_domain.txt @@ -81,7 +81,7 @@ Example 3: child: power-controller@12341000 { compatible = "foo,power-controller"; reg = <0x12341000 0x1000>; - power-domains = <&parent 0>; + power-domains = <&parent>; #power-domain-cells = <0>; domain-idle-states = <&DOMAIN_PWR_DN>; }; diff --git a/Documentation/devicetree/bindings/pwm/atmel-pwm.txt b/Documentation/devicetree/bindings/pwm/atmel-pwm.txt index 02331b904d4e..c8c831d7b0d1 100644 --- a/Documentation/devicetree/bindings/pwm/atmel-pwm.txt +++ b/Documentation/devicetree/bindings/pwm/atmel-pwm.txt @@ -4,6 +4,7 @@ Required properties: - compatible: should be one of: - "atmel,at91sam9rl-pwm" - "atmel,sama5d3-pwm" + - "atmel,sama5d2-pwm" - reg: physical base address and length of the controller's registers - #pwm-cells: Should be 3. See pwm.txt in this directory for a description of the cells format. diff --git a/Documentation/devicetree/bindings/pwm/nvidia,tegra20-pwm.txt b/Documentation/devicetree/bindings/pwm/nvidia,tegra20-pwm.txt index b4e73778dda3..c57e11b8d937 100644 --- a/Documentation/devicetree/bindings/pwm/nvidia,tegra20-pwm.txt +++ b/Documentation/devicetree/bindings/pwm/nvidia,tegra20-pwm.txt @@ -19,6 +19,19 @@ Required properties: - reset-names: Must include the following entries: - pwm +Optional properties: +============================ +In some of the interface like PWM based regulator device, it is required +to configure the pins differently in different states, especially in suspend +state of the system. The configuration of pin is provided via the pinctrl +DT node as detailed in the pinctrl DT binding document + Documentation/devicetree/bindings/pinctrl/pinctrl-bindings.txt + +The PWM node will have following optional properties. +pinctrl-names: Pin state names. Must be "default" and "sleep". +pinctrl-0: phandle for the default/active state of pin configurations. +pinctrl-1: phandle for the sleep state of pin configurations. + Example: pwm: pwm@7000a000 { @@ -29,3 +42,35 @@ Example: resets = <&tegra_car 17>; reset-names = "pwm"; }; + + +Example with the pin configuration for suspend and resume: +========================================================= +Suppose pin PE7 (On Tegra210) interfaced with the regulator device and +it requires PWM output to be tristated when system enters suspend. +Following will be DT binding to achieve this: + +#include <dt-bindings/pinctrl/pinctrl-tegra.h> + + pinmux@700008d4 { + pwm_active_state: pwm_active_state { + pe7 { + nvidia,pins = "pe7"; + nvidia,tristate = <TEGRA_PIN_DISABLE>; + }; + }; + + pwm_sleep_state: pwm_sleep_state { + pe7 { + nvidia,pins = "pe7"; + nvidia,tristate = <TEGRA_PIN_ENABLE>; + }; + }; + }; + + pwm@7000a000 { + /* Mandatory PWM properties */ + pinctrl-names = "default", "sleep"; + pinctrl-0 = <&pwm_active_state>; + pinctrl-1 = <&pwm_sleep_state>; + }; diff --git a/Documentation/devicetree/bindings/pwm/pwm-mediatek.txt b/Documentation/devicetree/bindings/pwm/pwm-mediatek.txt new file mode 100644 index 000000000000..54c59b0560ad --- /dev/null +++ b/Documentation/devicetree/bindings/pwm/pwm-mediatek.txt @@ -0,0 +1,34 @@ +MediaTek PWM controller + +Required properties: + - compatible: should be "mediatek,<name>-pwm": + - "mediatek,mt7623-pwm": found on mt7623 SoC. + - reg: physical base address and length of the controller's registers. + - #pwm-cells: must be 2. See pwm.txt in this directory for a description of + the cell format. + - clocks: phandle and clock specifier of the PWM reference clock. + - clock-names: must contain the following: + - "top": the top clock generator + - "main": clock used by the PWM core + - "pwm1-5": the five per PWM clocks + - pinctrl-names: Must contain a "default" entry. + - pinctrl-0: One property must exist for each entry in pinctrl-names. + See pinctrl/pinctrl-bindings.txt for details of the property values. + +Example: + pwm0: pwm@11006000 { + compatible = "mediatek,mt7623-pwm"; + reg = <0 0x11006000 0 0x1000>; + #pwm-cells = <2>; + clocks = <&topckgen CLK_TOP_PWM_SEL>, + <&pericfg CLK_PERI_PWM>, + <&pericfg CLK_PERI_PWM1>, + <&pericfg CLK_PERI_PWM2>, + <&pericfg CLK_PERI_PWM3>, + <&pericfg CLK_PERI_PWM4>, + <&pericfg CLK_PERI_PWM5>; + clock-names = "top", "main", "pwm1", "pwm2", + "pwm3", "pwm4", "pwm5"; + pinctrl-names = "default"; + pinctrl-0 = <&pwm0_pins>; + }; diff --git a/Documentation/devicetree/bindings/rtc/cpcap-rtc.txt b/Documentation/devicetree/bindings/rtc/cpcap-rtc.txt new file mode 100644 index 000000000000..45750ff3112d --- /dev/null +++ b/Documentation/devicetree/bindings/rtc/cpcap-rtc.txt @@ -0,0 +1,18 @@ +Motorola CPCAP PMIC RTC +----------------------- + +This module is part of the CPCAP. For more details about the whole +chip see Documentation/devicetree/bindings/mfd/motorola-cpcap.txt. + +Requires node properties: +- compatible: should contain "motorola,cpcap-rtc" +- interrupts: An interrupt specifier for alarm and 1 Hz irq + +Example: + +&cpcap { + cpcap_rtc: rtc { + compatible = "motorola,cpcap-rtc"; + interrupts = <39 IRQ_TYPE_NONE>, <26 IRQ_TYPE_NONE>; + }; +}; diff --git a/Documentation/devicetree/bindings/rtc/rtc-sh.txt b/Documentation/devicetree/bindings/rtc/rtc-sh.txt new file mode 100644 index 000000000000..7676c7d28874 --- /dev/null +++ b/Documentation/devicetree/bindings/rtc/rtc-sh.txt @@ -0,0 +1,28 @@ +* Real Time Clock for Renesas SH and ARM SoCs + +Required properties: +- compatible: Should be "renesas,r7s72100-rtc" and "renesas,sh-rtc" as a + fallback. +- reg: physical base address and length of memory mapped region. +- interrupts: 3 interrupts for alarm, period, and carry. +- interrupt-names: The interrupts should be labeled as "alarm", "period", and + "carry". +- clocks: The functional clock source for the RTC controller must be listed + first (if exists). Additionally, potential clock counting sources are to be + listed. +- clock-names: The functional clock must be labeled as "fck". Other clocks + may be named in accordance to the SoC hardware manuals. + + +Example: +rtc: rtc@fcff1000 { + compatible = "renesas,r7s72100-rtc", "renesas,sh-rtc"; + reg = <0xfcff1000 0x2e>; + interrupts = <GIC_SPI 276 IRQ_TYPE_EDGE_RISING + GIC_SPI 277 IRQ_TYPE_EDGE_RISING + GIC_SPI 278 IRQ_TYPE_EDGE_RISING>; + interrupt-names = "alarm", "period", "carry"; + clocks = <&mstp6_clks R7S72100_CLK_RTC>, <&rtc_x1_clk>, + <&rtc_x3_clk>, <&extal_clk>; + clock-names = "fck", "rtc_x1", "rtc_x3", "extal"; +}; diff --git a/Documentation/devicetree/bindings/trivial-devices.txt b/Documentation/devicetree/bindings/trivial-devices.txt index ad10fbe61562..3e0a34c88e07 100644 --- a/Documentation/devicetree/bindings/trivial-devices.txt +++ b/Documentation/devicetree/bindings/trivial-devices.txt @@ -160,6 +160,7 @@ sii,s35390a 2-wire CMOS real-time clock silabs,si7020 Relative Humidity and Temperature Sensors skyworks,sky81452 Skyworks SKY81452: Six-Channel White LED Driver with Touch Panel Bias Supply st,24c256 i2c serial eeprom (24cxx) +st,m41t0 Serial real-time clock (RTC) st,m41t00 Serial real-time clock (RTC) st,m41t62 Serial real-time clock (RTC) with alarm st,m41t80 M41T80 - SERIAL ACCESS RTC WITH ALARMS diff --git a/Documentation/devicetree/bindings/usb/da8xx-usb.txt b/Documentation/devicetree/bindings/usb/da8xx-usb.txt index ccb844aba7d4..717c5f656237 100644 --- a/Documentation/devicetree/bindings/usb/da8xx-usb.txt +++ b/Documentation/devicetree/bindings/usb/da8xx-usb.txt @@ -18,10 +18,26 @@ Required properties: - phy-names: Should be "usb-phy" + - dmas: specifies the dma channels + + - dma-names: specifies the names of the channels. Use "rxN" for receive + and "txN" for transmit endpoints. N specifies the endpoint number. + Optional properties: ~~~~~~~~~~~~~~~~~~~~ - vbus-supply: Phandle to a regulator providing the USB bus power. +DMA +~~~ +- compatible: ti,da830-cppi41 +- reg: offset and length of the following register spaces: CPPI DMA Controller, + CPPI DMA Scheduler, Queue Manager +- reg-names: "controller", "scheduler", "queuemgr" +- #dma-cells: should be set to 2. The first number represents the + channel number (0 … 3 for endpoints 1 … 4). + The second number is 0 for RX and 1 for TX transfers. +- #dma-channels: should be set to 4 representing the 4 endpoints. + Example: usb_phy: usb-phy { compatible = "ti,da830-usb-phy"; @@ -30,7 +46,10 @@ Example: }; usb0: usb@200000 { compatible = "ti,da830-musb"; - reg = <0x00200000 0x10000>; + reg = <0x00200000 0x1000>; + ranges; + #address-cells = <1>; + #size-cells = <1>; interrupts = <58>; interrupt-names = "mc"; @@ -39,5 +58,25 @@ Example: phys = <&usb_phy 0>; phy-names = "usb-phy"; + dmas = <&cppi41dma 0 0 &cppi41dma 1 0 + &cppi41dma 2 0 &cppi41dma 3 0 + &cppi41dma 0 1 &cppi41dma 1 1 + &cppi41dma 2 1 &cppi41dma 3 1>; + dma-names = + "rx1", "rx2", "rx3", "rx4", + "tx1", "tx2", "tx3", "tx4"; + status = "okay"; + + cppi41dma: dma-controller@201000 { + compatible = "ti,da830-cppi41"; + reg = <0x201000 0x1000 + 0x202000 0x1000 + 0x204000 0x4000>; + reg-names = "controller", "scheduler", "queuemgr"; + interrupts = <58>; + #dma-cells = <2>; + #dma-channels = <4>; + }; + }; diff --git a/Documentation/devicetree/bindings/vendor-prefixes.txt b/Documentation/devicetree/bindings/vendor-prefixes.txt index f9fe94535b46..c03d20140366 100644 --- a/Documentation/devicetree/bindings/vendor-prefixes.txt +++ b/Documentation/devicetree/bindings/vendor-prefixes.txt @@ -173,6 +173,7 @@ lego LEGO Systems A/S lenovo Lenovo Group Ltd. lg LG Corporation licheepi Lichee Pi +linaro Linaro Limited linux Linux-specific binding lltc Linear Technology Corporation lsi LSI Corp. (LSI Logic) @@ -196,6 +197,7 @@ minix MINIX Technology Ltd. miramems MiraMEMS Sensing Technology Co., Ltd. mitsubishi Mitsubishi Electric Corporation mosaixtech Mosaix Technologies, Inc. +motorola Motorola, Inc. moxa Moxa mpl MPL AG mqmaker mqmaker Inc. diff --git a/Documentation/filesystems/nfs/pnfs.txt b/Documentation/filesystems/nfs/pnfs.txt index 8de578a98222..80dc0bdc302a 100644 --- a/Documentation/filesystems/nfs/pnfs.txt +++ b/Documentation/filesystems/nfs/pnfs.txt @@ -64,46 +64,9 @@ table which are called by the nfs-client pnfs-core to implement the different layout types. Files-layout-driver code is in: fs/nfs/filelayout/.. directory -Objects-layout-driver code is in: fs/nfs/objlayout/.. directory Blocks-layout-driver code is in: fs/nfs/blocklayout/.. directory Flexfiles-layout-driver code is in: fs/nfs/flexfilelayout/.. directory -objects-layout setup --------------------- - -As part of the full STD implementation the objlayoutdriver.ko needs, at times, -to automatically login to yet undiscovered iscsi/osd devices. For this the -driver makes up-calles to a user-mode script called *osd_login* - -The path_name of the script to use is by default: - /sbin/osd_login. -This name can be overridden by the Kernel module parameter: - objlayoutdriver.osd_login_prog - -If Kernel does not find the osd_login_prog path it will zero it out -and will not attempt farther logins. An admin can then write new value -to the objlayoutdriver.osd_login_prog Kernel parameter to re-enable it. - -The /sbin/osd_login is part of the nfs-utils package, and should usually -be installed on distributions that support this Kernel version. - -The API to the login script is as follows: - Usage: $0 -u <URI> -o <OSDNAME> -s <SYSTEMID> - Options: - -u target uri e.g. iscsi://<ip>:<port> - (always exists) - (More protocols can be defined in the future. - The client does not interpret this string it is - passed unchanged as received from the Server) - -o osdname of the requested target OSD - (Might be empty) - (A string which denotes the OSD name, there is a - limit of 64 chars on this string) - -s systemid of the requested target OSD - (Might be empty) - (This string, if not empty is always an hex - representation of the 20 bytes osd_system_id) - blocks-layout setup ------------------- diff --git a/Documentation/filesystems/overlayfs.txt b/Documentation/filesystems/overlayfs.txt index 634d03e20c2d..c9e884b52698 100644 --- a/Documentation/filesystems/overlayfs.txt +++ b/Documentation/filesystems/overlayfs.txt @@ -21,12 +21,19 @@ from accessing the corresponding object from the original filesystem. This is most obvious from the 'st_dev' field returned by stat(2). While directories will report an st_dev from the overlay-filesystem, -all non-directory objects will report an st_dev from the lower or +non-directory objects may report an st_dev from the lower filesystem or upper filesystem that is providing the object. Similarly st_ino will only be unique when combined with st_dev, and both of these can change over the lifetime of a non-directory object. Many applications and tools ignore these values and will not be affected. +In the special case of all overlay layers on the same underlying +filesystem, all objects will report an st_dev from the overlay +filesystem and st_ino from the underlying filesystem. This will +make the overlay mount more compliant with filesystem scanners and +overlay objects will be distinguishable from the corresponding +objects in the original filesystem. + Upper and Lower --------------- diff --git a/Documentation/ioctl/ioctl-number.txt b/Documentation/ioctl/ioctl-number.txt index eccb675a2852..1e9fcb4d0ec8 100644 --- a/Documentation/ioctl/ioctl-number.txt +++ b/Documentation/ioctl/ioctl-number.txt @@ -309,6 +309,7 @@ Code Seq#(hex) Include File Comments 0xA3 80-8F Port ACL in development: <mailto:tlewis@mindspring.com> 0xA3 90-9F linux/dtlk.h +0xA4 00-1F uapi/linux/tee.h Generic TEE subsystem 0xAA 00-3F linux/uapi/linux/userfaultfd.h 0xAB 00-1F linux/nbd.h 0xAC 00-1F linux/raw.h diff --git a/Documentation/kbuild/makefiles.txt b/Documentation/kbuild/makefiles.txt index 9b9c4797fc55..e18daca65ccd 100644 --- a/Documentation/kbuild/makefiles.txt +++ b/Documentation/kbuild/makefiles.txt @@ -44,11 +44,11 @@ This document describes the Linux kernel Makefiles. --- 6.11 Post-link pass === 7 Kbuild syntax for exported headers - --- 7.1 header-y + --- 7.1 no-export-headers --- 7.2 genhdr-y - --- 7.3 destination-y - --- 7.4 generic-y - --- 7.5 generated-y + --- 7.3 generic-y + --- 7.4 generated-y + --- 7.5 mandatory-y === 8 Kbuild Variables === 9 Makefile language @@ -1236,7 +1236,7 @@ When kbuild executes, the following steps are followed (roughly): that may be shared between individual architectures. The recommended approach how to use a generic header file is to list the file in the Kbuild file. - See "7.4 generic-y" for further info on syntax etc. + See "7.3 generic-y" for further info on syntax etc. --- 6.11 Post-link pass @@ -1263,53 +1263,32 @@ The pre-processing does: - drop include of compiler.h - drop all sections that are kernel internal (guarded by ifdef __KERNEL__) -Each relevant directory contains a file name "Kbuild" which specifies the -headers to be exported. -See subsequent chapter for the syntax of the Kbuild file. - - --- 7.1 header-y - - header-y specifies header files to be exported. - - Example: - #include/linux/Kbuild - header-y += usb/ - header-y += aio_abi.h +All headers under include/uapi/, include/generated/uapi/, +arch/<arch>/include/uapi/ and arch/<arch>/include/generated/uapi/ +are exported. - The convention is to list one file per line and - preferably in alphabetic order. +A Kbuild file may be defined under arch/<arch>/include/uapi/asm/ and +arch/<arch>/include/asm/ to list asm files coming from asm-generic. +See subsequent chapter for the syntax of the Kbuild file. - header-y also specifies which subdirectories to visit. - A subdirectory is identified by a trailing '/' which - can be seen in the example above for the usb subdirectory. + --- 7.1 no-export-headers - Subdirectories are visited before their parent directories. + no-export-headers is essentially used by include/uapi/linux/Kbuild to + avoid exporting specific headers (e.g. kvm.h) on architectures that do + not support it. It should be avoided as much as possible. --- 7.2 genhdr-y - genhdr-y specifies generated files to be exported. - Generated files are special as they need to be looked - up in another directory when doing 'make O=...' builds. + genhdr-y specifies asm files to be generated. Example: - #include/linux/Kbuild - genhdr-y += version.h + #arch/x86/include/uapi/asm/Kbuild + genhdr-y += unistd_32.h + genhdr-y += unistd_64.h + genhdr-y += unistd_x32.h - --- 7.3 destination-y - When an architecture has a set of exported headers that needs to be - exported to a different directory destination-y is used. - destination-y specifies the destination directory for all exported - headers in the file where it is present. - - Example: - #arch/xtensa/platforms/s6105/include/platform/Kbuild - destination-y := include/linux - - In the example above all exported headers in the Kbuild file - will be located in the directory "include/linux" when exported. - - --- 7.4 generic-y + --- 7.3 generic-y If an architecture uses a verbatim copy of a header from include/asm-generic then this is listed in the file @@ -1336,7 +1315,7 @@ See subsequent chapter for the syntax of the Kbuild file. Example: termios.h #include <asm-generic/termios.h> - --- 7.5 generated-y + --- 7.4 generated-y If an architecture generates other header files alongside generic-y wrappers, and not included in genhdr-y, then generated-y specifies @@ -1349,6 +1328,15 @@ See subsequent chapter for the syntax of the Kbuild file. #arch/x86/include/asm/Kbuild generated-y += syscalls_32.h + --- 7.5 mandatory-y + + mandatory-y is essentially used by include/uapi/asm-generic/Kbuild.asm + to define the minimun set of headers that must be exported in + include/asm. + + The convention is to list one subdir per line and + preferably in alphabetic order. + === 8 Kbuild Variables The top Makefile exports the following variables: diff --git a/Documentation/memory-barriers.txt b/Documentation/memory-barriers.txt index d323adcb7b88..732f10ea382e 100644 --- a/Documentation/memory-barriers.txt +++ b/Documentation/memory-barriers.txt @@ -768,7 +768,7 @@ equal to zero, in which case the compiler is within its rights to transform the above code into the following: q = READ_ONCE(a); - WRITE_ONCE(b, 1); + WRITE_ONCE(b, 2); do_something_else(); Given this transformation, the CPU is not required to respect the ordering diff --git a/Documentation/tee.txt b/Documentation/tee.txt new file mode 100644 index 000000000000..718599357596 --- /dev/null +++ b/Documentation/tee.txt @@ -0,0 +1,118 @@ +TEE subsystem +This document describes the TEE subsystem in Linux. + +A TEE (Trusted Execution Environment) is a trusted OS running in some +secure environment, for example, TrustZone on ARM CPUs, or a separate +secure co-processor etc. A TEE driver handles the details needed to +communicate with the TEE. + +This subsystem deals with: + +- Registration of TEE drivers + +- Managing shared memory between Linux and the TEE + +- Providing a generic API to the TEE + +The TEE interface +================= + +include/uapi/linux/tee.h defines the generic interface to a TEE. + +User space (the client) connects to the driver by opening /dev/tee[0-9]* or +/dev/teepriv[0-9]*. + +- TEE_IOC_SHM_ALLOC allocates shared memory and returns a file descriptor + which user space can mmap. When user space doesn't need the file + descriptor any more, it should be closed. When shared memory isn't needed + any longer it should be unmapped with munmap() to allow the reuse of + memory. + +- TEE_IOC_VERSION lets user space know which TEE this driver handles and + the its capabilities. + +- TEE_IOC_OPEN_SESSION opens a new session to a Trusted Application. + +- TEE_IOC_INVOKE invokes a function in a Trusted Application. + +- TEE_IOC_CANCEL may cancel an ongoing TEE_IOC_OPEN_SESSION or TEE_IOC_INVOKE. + +- TEE_IOC_CLOSE_SESSION closes a session to a Trusted Application. + +There are two classes of clients, normal clients and supplicants. The latter is +a helper process for the TEE to access resources in Linux, for example file +system access. A normal client opens /dev/tee[0-9]* and a supplicant opens +/dev/teepriv[0-9]. + +Much of the communication between clients and the TEE is opaque to the +driver. The main job for the driver is to receive requests from the +clients, forward them to the TEE and send back the results. In the case of +supplicants the communication goes in the other direction, the TEE sends +requests to the supplicant which then sends back the result. + +OP-TEE driver +============= + +The OP-TEE driver handles OP-TEE [1] based TEEs. Currently it is only the ARM +TrustZone based OP-TEE solution that is supported. + +Lowest level of communication with OP-TEE builds on ARM SMC Calling +Convention (SMCCC) [2], which is the foundation for OP-TEE's SMC interface +[3] used internally by the driver. Stacked on top of that is OP-TEE Message +Protocol [4]. + +OP-TEE SMC interface provides the basic functions required by SMCCC and some +additional functions specific for OP-TEE. The most interesting functions are: + +- OPTEE_SMC_FUNCID_CALLS_UID (part of SMCCC) returns the version information + which is then returned by TEE_IOC_VERSION + +- OPTEE_SMC_CALL_GET_OS_UUID returns the particular OP-TEE implementation, used + to tell, for instance, a TrustZone OP-TEE apart from an OP-TEE running on a + separate secure co-processor. + +- OPTEE_SMC_CALL_WITH_ARG drives the OP-TEE message protocol + +- OPTEE_SMC_GET_SHM_CONFIG lets the driver and OP-TEE agree on which memory + range to used for shared memory between Linux and OP-TEE. + +The GlobalPlatform TEE Client API [5] is implemented on top of the generic +TEE API. + +Picture of the relationship between the different components in the +OP-TEE architecture. + + User space Kernel Secure world + ~~~~~~~~~~ ~~~~~~ ~~~~~~~~~~~~ + +--------+ +-------------+ + | Client | | Trusted | + +--------+ | Application | + /\ +-------------+ + || +----------+ /\ + || |tee- | || + || |supplicant| \/ + || +----------+ +-------------+ + \/ /\ | TEE Internal| + +-------+ || | API | + + TEE | || +--------+--------+ +-------------+ + | Client| || | TEE | OP-TEE | | OP-TEE | + | API | \/ | subsys | driver | | Trusted OS | + +-------+----------------+----+-------+----+-----------+-------------+ + | Generic TEE API | | OP-TEE MSG | + | IOCTL (TEE_IOC_*) | | SMCCC (OPTEE_SMC_CALL_*) | + +-----------------------------+ +------------------------------+ + +RPC (Remote Procedure Call) are requests from secure world to kernel driver +or tee-supplicant. An RPC is identified by a special range of SMCCC return +values from OPTEE_SMC_CALL_WITH_ARG. RPC messages which are intended for the +kernel are handled by the kernel driver. Other RPC messages will be forwarded to +tee-supplicant without further involvement of the driver, except switching +shared memory buffer representation. + +References: +[1] https://github.com/OP-TEE/optee_os +[2] http://infocenter.arm.com/help/topic/com.arm.doc.den0028a/index.html +[3] drivers/tee/optee/optee_smc.h +[4] drivers/tee/optee/optee_msg.h +[5] http://www.globalplatform.org/specificationsdevice.asp look for + "TEE Client API Specification v1.0" and click download. diff --git a/Documentation/virtual/kvm/devices/arm-vgic-its.txt b/Documentation/virtual/kvm/devices/arm-vgic-its.txt index 6081a5b7fc1e..eb06beb75960 100644 --- a/Documentation/virtual/kvm/devices/arm-vgic-its.txt +++ b/Documentation/virtual/kvm/devices/arm-vgic-its.txt @@ -32,7 +32,128 @@ Groups: KVM_DEV_ARM_VGIC_CTRL_INIT request the initialization of the ITS, no additional parameter in kvm_device_attr.addr. + + KVM_DEV_ARM_ITS_SAVE_TABLES + save the ITS table data into guest RAM, at the location provisioned + by the guest in corresponding registers/table entries. + + The layout of the tables in guest memory defines an ABI. The entries + are laid out in little endian format as described in the last paragraph. + + KVM_DEV_ARM_ITS_RESTORE_TABLES + restore the ITS tables from guest RAM to ITS internal structures. + + The GICV3 must be restored before the ITS and all ITS registers but + the GITS_CTLR must be restored before restoring the ITS tables. + + The GITS_IIDR read-only register must also be restored before + calling KVM_DEV_ARM_ITS_RESTORE_TABLES as the IIDR revision field + encodes the ABI revision. + + The expected ordering when restoring the GICv3/ITS is described in section + "ITS Restore Sequence". + Errors: -ENXIO: ITS not properly configured as required prior to setting this attribute -ENOMEM: Memory shortage when allocating ITS internal data + -EINVAL: Inconsistent restored data + -EFAULT: Invalid guest ram access + -EBUSY: One or more VCPUS are running + + KVM_DEV_ARM_VGIC_GRP_ITS_REGS + Attributes: + The attr field of kvm_device_attr encodes the offset of the + ITS register, relative to the ITS control frame base address + (ITS_base). + + kvm_device_attr.addr points to a __u64 value whatever the width + of the addressed register (32/64 bits). 64 bit registers can only + be accessed with full length. + + Writes to read-only registers are ignored by the kernel except for: + - GITS_CREADR. It must be restored otherwise commands in the queue + will be re-executed after restoring CWRITER. GITS_CREADR must be + restored before restoring the GITS_CTLR which is likely to enable the + ITS. Also it must be restored after GITS_CBASER since a write to + GITS_CBASER resets GITS_CREADR. + - GITS_IIDR. The Revision field encodes the table layout ABI revision. + In the future we might implement direct injection of virtual LPIs. + This will require an upgrade of the table layout and an evolution of + the ABI. GITS_IIDR must be restored before calling + KVM_DEV_ARM_ITS_RESTORE_TABLES. + + For other registers, getting or setting a register has the same + effect as reading/writing the register on real hardware. + Errors: + -ENXIO: Offset does not correspond to any supported register + -EFAULT: Invalid user pointer for attr->addr + -EINVAL: Offset is not 64-bit aligned + -EBUSY: one or more VCPUS are running + + ITS Restore Sequence: + ------------------------- + +The following ordering must be followed when restoring the GIC and the ITS: +a) restore all guest memory and create vcpus +b) restore all redistributors +c) provide the its base address + (KVM_DEV_ARM_VGIC_GRP_ADDR) +d) restore the ITS in the following order: + 1. Restore GITS_CBASER + 2. Restore all other GITS_ registers, except GITS_CTLR! + 3. Load the ITS table data (KVM_DEV_ARM_ITS_RESTORE_TABLES) + 4. Restore GITS_CTLR + +Then vcpus can be started. + + ITS Table ABI REV0: + ------------------- + + Revision 0 of the ABI only supports the features of a virtual GICv3, and does + not support a virtual GICv4 with support for direct injection of virtual + interrupts for nested hypervisors. + + The device table and ITT are indexed by the DeviceID and EventID, + respectively. The collection table is not indexed by CollectionID, and the + entries in the collection are listed in no particular order. + All entries are 8 bytes. + + Device Table Entry (DTE): + + bits: | 63| 62 ... 49 | 48 ... 5 | 4 ... 0 | + values: | V | next | ITT_addr | Size | + + where; + - V indicates whether the entry is valid. If not, other fields + are not meaningful. + - next: equals to 0 if this entry is the last one; otherwise it + corresponds to the DeviceID offset to the next DTE, capped by + 2^14 -1. + - ITT_addr matches bits [51:8] of the ITT address (256 Byte aligned). + - Size specifies the supported number of bits for the EventID, + minus one + + Collection Table Entry (CTE): + + bits: | 63| 62 .. 52 | 51 ... 16 | 15 ... 0 | + values: | V | RES0 | RDBase | ICID | + + where: + - V indicates whether the entry is valid. If not, other fields are + not meaningful. + - RES0: reserved field with Should-Be-Zero-or-Preserved behavior. + - RDBase is the PE number (GICR_TYPER.Processor_Number semantic), + - ICID is the collection ID + + Interrupt Translation Entry (ITE): + + bits: | 63 ... 48 | 47 ... 16 | 15 ... 0 | + values: | next | pINTID | ICID | + + where: + - next: equals to 0 if this entry is the last one; otherwise it corresponds + to the EventID offset to the next ITE capped by 2^16 -1. + - pINTID is the physical LPI ID; if zero, it means the entry is not valid + and other fields are not meaningful. + - ICID is the collection ID diff --git a/Documentation/virtual/kvm/devices/arm-vgic-v3.txt b/Documentation/virtual/kvm/devices/arm-vgic-v3.txt index c1a24612c198..9293b45abdb9 100644 --- a/Documentation/virtual/kvm/devices/arm-vgic-v3.txt +++ b/Documentation/virtual/kvm/devices/arm-vgic-v3.txt @@ -167,11 +167,17 @@ Groups: KVM_DEV_ARM_VGIC_CTRL_INIT request the initialization of the VGIC, no additional parameter in kvm_device_attr.addr. + KVM_DEV_ARM_VGIC_SAVE_PENDING_TABLES + save all LPI pending bits into guest RAM pending tables. + + The first kB of the pending table is not altered by this operation. Errors: -ENXIO: VGIC not properly configured as required prior to calling this attribute -ENODEV: no online VCPU -ENOMEM: memory shortage when allocating vgic internal data + -EFAULT: Invalid guest ram access + -EBUSY: One or more VCPUS are running KVM_DEV_ARM_VGIC_GRP_LEVEL_INFO |
