summaryrefslogtreecommitdiffstats
path: root/kernel/context_tracking.c (follow)
Commit message (Collapse)AuthorAgeFilesLines
* context_tracking: Fix noinstr vs KASANPeter Zijlstra2023-01-131-6/+6
| | | | | | | | | | | | | | Low level noinstr context-tracking code is calling out to instrumented code on KASAN: vmlinux.o: warning: objtool: __ct_user_enter+0x72: call to __kasan_check_write() leaves .noinstr.text section vmlinux.o: warning: objtool: __ct_user_exit+0x47: call to __kasan_check_write() leaves .noinstr.text section Use even lower level atomic methods to avoid the instrumentation. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lore.kernel.org/r/20230112195542.458034262@infradead.org
* MAINTAINERS: Add Paul as context tracking maintainerFrederic Weisbecker2022-07-051-5/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | Since most of the bits have been imported from kernel/rcu/tree.c and now that the context tracking code is tightly linked to RCU, add Paul as a context tracking maintainer. Also update the context tracking file header accordingly. Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Neeraj Upadhyay <quic_neeraju@quicinc.com> Cc: Uladzislau Rezki <uladzislau.rezki@sony.com> Cc: Joel Fernandes <joel@joelfernandes.org> Cc: Boqun Feng <boqun.feng@gmail.com> Cc: Nicolas Saenz Julienne <nsaenz@kernel.org> Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: Xiongfeng Wang <wangxiongfeng2@huawei.com> Cc: Yu Liao <liaoyu15@huawei.com> Cc: Phil Auld <pauld@redhat.com> Cc: Paul Gortmaker<paul.gortmaker@windriver.com> Cc: Alex Belits <abelits@marvell.com> Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Reviewed-by: Nicolas Saenz Julienne <nsaenzju@redhat.com> Tested-by: Nicolas Saenz Julienne <nsaenzju@redhat.com>
* context_tracking: Convert state to atomic_tFrederic Weisbecker2022-07-051-49/+94
| | | | | | | | | | | | | | | | | | | | | | | | | | Context tracking's state and dynticks counter are going to be merged in a single field so that both updates can happen atomically and at the same time. Prepare for that with converting the state into an atomic_t. [ paulmck: Apply kernel test robot feedback. ] Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Neeraj Upadhyay <quic_neeraju@quicinc.com> Cc: Uladzislau Rezki <uladzislau.rezki@sony.com> Cc: Joel Fernandes <joel@joelfernandes.org> Cc: Boqun Feng <boqun.feng@gmail.com> Cc: Nicolas Saenz Julienne <nsaenz@kernel.org> Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: Xiongfeng Wang <wangxiongfeng2@huawei.com> Cc: Yu Liao <liaoyu15@huawei.com> Cc: Phil Auld <pauld@redhat.com> Cc: Paul Gortmaker<paul.gortmaker@windriver.com> Cc: Alex Belits <abelits@marvell.com> Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Reviewed-by: Nicolas Saenz Julienne <nsaenzju@redhat.com> Tested-by: Nicolas Saenz Julienne <nsaenzju@redhat.com>
* rcu/context-tracking: Remove unused and/or unecessary middle functionsFrederic Weisbecker2022-07-051-71/+27
| | | | | | | | | | | | | | | | | | | | | | | | | | | Some eqs functions are now only used internally by context tracking, so their public declarations can be removed. Also middle functions such as rcu_user_*() and rcu_idle_*() which now directly call to rcu_eqs_enter() and rcu_eqs_exit() can be wiped out as well. Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Neeraj Upadhyay <quic_neeraju@quicinc.com> Cc: Uladzislau Rezki <uladzislau.rezki@sony.com> Cc: Joel Fernandes <joel@joelfernandes.org> Cc: Boqun Feng <boqun.feng@gmail.com> Cc: Nicolas Saenz Julienne <nsaenz@kernel.org> Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: Xiongfeng Wang <wangxiongfeng2@huawei.com> Cc: Yu Liao <liaoyu15@huawei.com> Cc: Phil Auld <pauld@redhat.com> Cc: Paul Gortmaker<paul.gortmaker@windriver.com> Cc: Alex Belits <abelits@marvell.com> Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Reviewed-by: Nicolas Saenz Julienne <nsaenzju@redhat.com> Tested-by: Nicolas Saenz Julienne <nsaenzju@redhat.com>
* rcu/context-tracking: Move RCU-dynticks internal functions to context_trackingFrederic Weisbecker2022-07-051-0/+336
| | | | | | | | | | | | | | | | | | | | | | | | Move the core RCU eqs/dynticks functions to context tracking so that we can later merge all that code within context tracking. Acked-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Neeraj Upadhyay <quic_neeraju@quicinc.com> Cc: Uladzislau Rezki <uladzislau.rezki@sony.com> Cc: Joel Fernandes <joel@joelfernandes.org> Cc: Boqun Feng <boqun.feng@gmail.com> Cc: Nicolas Saenz Julienne <nsaenz@kernel.org> Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: Xiongfeng Wang <wangxiongfeng2@huawei.com> Cc: Yu Liao <liaoyu15@huawei.com> Cc: Phil Auld <pauld@redhat.com> Cc: Paul Gortmaker<paul.gortmaker@windriver.com> Cc: Alex Belits <abelits@marvell.com> Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Reviewed-by: Nicolas Saenz Julienne <nsaenzju@redhat.com> Tested-by: Nicolas Saenz Julienne <nsaenzju@redhat.com>
* rcu/context-tracking: Move deferred nocb resched to context trackingFrederic Weisbecker2022-07-051-0/+8
| | | | | | | | | | | | | | | | | | | | | | | | | To prepare for migrating the RCU eqs accounting code to context tracking, split the last-resort deferred nocb resched from rcu_user_enter() and move it into a separate call from context tracking. Acked-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Neeraj Upadhyay <quic_neeraju@quicinc.com> Cc: Uladzislau Rezki <uladzislau.rezki@sony.com> Cc: Joel Fernandes <joel@joelfernandes.org> Cc: Boqun Feng <boqun.feng@gmail.com> Cc: Nicolas Saenz Julienne <nsaenz@kernel.org> Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: Xiongfeng Wang <wangxiongfeng2@huawei.com> Cc: Yu Liao <liaoyu15@huawei.com> Cc: Phil Auld <pauld@redhat.com> Cc: Paul Gortmaker<paul.gortmaker@windriver.com> Cc: Alex Belits <abelits@marvell.com> Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Reviewed-by: Nicolas Saenz Julienne <nsaenzju@redhat.com> Tested-by: Nicolas Saenz Julienne <nsaenzju@redhat.com>
* rcu/context_tracking: Move dynticks_nmi_nesting to context trackingFrederic Weisbecker2022-07-051-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | The RCU eqs tracking is going to be performed by the context tracking subsystem. The related nesting counters thus need to be moved to the context tracking structure. Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Neeraj Upadhyay <quic_neeraju@quicinc.com> Cc: Uladzislau Rezki <uladzislau.rezki@sony.com> Cc: Joel Fernandes <joel@joelfernandes.org> Cc: Boqun Feng <boqun.feng@gmail.com> Cc: Nicolas Saenz Julienne <nsaenz@kernel.org> Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: Xiongfeng Wang <wangxiongfeng2@huawei.com> Cc: Yu Liao <liaoyu15@huawei.com> Cc: Phil Auld <pauld@redhat.com> Cc: Paul Gortmaker<paul.gortmaker@windriver.com> Cc: Alex Belits <abelits@marvell.com> Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Reviewed-by: Nicolas Saenz Julienne <nsaenzju@redhat.com> Tested-by: Nicolas Saenz Julienne <nsaenzju@redhat.com>
* rcu/context_tracking: Move dynticks_nesting to context trackingFrederic Weisbecker2022-07-051-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | The RCU eqs tracking is going to be performed by the context tracking subsystem. The related nesting counters thus need to be moved to the context tracking structure. Acked-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Neeraj Upadhyay <quic_neeraju@quicinc.com> Cc: Uladzislau Rezki <uladzislau.rezki@sony.com> Cc: Joel Fernandes <joel@joelfernandes.org> Cc: Boqun Feng <boqun.feng@gmail.com> Cc: Nicolas Saenz Julienne <nsaenz@kernel.org> Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: Xiongfeng Wang <wangxiongfeng2@huawei.com> Cc: Yu Liao <liaoyu15@huawei.com> Cc: Phil Auld <pauld@redhat.com> Cc: Paul Gortmaker<paul.gortmaker@windriver.com> Cc: Alex Belits <abelits@marvell.com> Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Reviewed-by: Nicolas Saenz Julienne <nsaenzju@redhat.com> Tested-by: Nicolas Saenz Julienne <nsaenzju@redhat.com>
* rcu/context_tracking: Move dynticks counter to context trackingFrederic Weisbecker2022-07-051-3/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | In order to prepare for merging RCU dynticks counter into the context tracking state, move the rcu_data's dynticks field to the context tracking structure. It will later be mixed within the context tracking state itself. [ paulmck: Move enum ctx_state into global scope. ] Acked-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Neeraj Upadhyay <quic_neeraju@quicinc.com> Cc: Uladzislau Rezki <uladzislau.rezki@sony.com> Cc: Joel Fernandes <joel@joelfernandes.org> Cc: Boqun Feng <boqun.feng@gmail.com> Cc: Nicolas Saenz Julienne <nsaenz@kernel.org> Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: Xiongfeng Wang <wangxiongfeng2@huawei.com> Cc: Yu Liao <liaoyu15@huawei.com> Cc: Phil Auld <pauld@redhat.com> Cc: Paul Gortmaker<paul.gortmaker@windriver.com> Cc: Alex Belits <abelits@marvell.com> Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Reviewed-by: Nicolas Saenz Julienne <nsaenzju@redhat.com> Tested-by: Nicolas Saenz Julienne <nsaenzju@redhat.com>
* rcu/context-tracking: Remove rcu_irq_enter/exit()Frederic Weisbecker2022-07-051-4/+67
| | | | | | | | | | | | | | | | | | | | | | | | | Now rcu_irq_enter/exit() is an unnecessary middle call between ct_irq_enter/exit() and nmi_irq_enter/exit(). Take this opportunity to remove the former functions and move the comments above them to the new entrypoints. Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Neeraj Upadhyay <quic_neeraju@quicinc.com> Cc: Uladzislau Rezki <uladzislau.rezki@sony.com> Cc: Joel Fernandes <joel@joelfernandes.org> Cc: Boqun Feng <boqun.feng@gmail.com> Cc: Nicolas Saenz Julienne <nsaenz@kernel.org> Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: Xiongfeng Wang <wangxiongfeng2@huawei.com> Cc: Yu Liao <liaoyu15@huawei.com> Cc: Phil Auld <pauld@redhat.com> Cc: Paul Gortmaker<paul.gortmaker@windriver.com> Cc: Alex Belits <abelits@marvell.com> Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Reviewed-by: Nicolas Saenz Julienne <nsaenzju@redhat.com> Tested-by: Nicolas Saenz Julienne <nsaenzju@redhat.com>
* context_tracking: Take NMI eqs entrypoints over RCUFrederic Weisbecker2022-07-051-0/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | The RCU dynticks counter is going to be merged into the context tracking subsystem. Prepare with moving the NMI extended quiescent states entrypoints to context tracking. For now those are dumb redirection to existing RCU calls. Acked-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Neeraj Upadhyay <quic_neeraju@quicinc.com> Cc: Uladzislau Rezki <uladzislau.rezki@sony.com> Cc: Joel Fernandes <joel@joelfernandes.org> Cc: Boqun Feng <boqun.feng@gmail.com> Cc: Nicolas Saenz Julienne <nsaenz@kernel.org> Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: Xiongfeng Wang <wangxiongfeng2@huawei.com> Cc: Yu Liao <liaoyu15@huawei.com> Cc: Phil Auld <pauld@redhat.com> Cc: Paul Gortmaker<paul.gortmaker@windriver.com> Cc: Alex Belits <abelits@marvell.com> Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Reviewed-by: Nicolas Saenz Julienne <nsaenzju@redhat.com> Tested-by: Nicolas Saenz Julienne <nsaenzju@redhat.com>
* context_tracking: Take IRQ eqs entrypoints over RCUFrederic Weisbecker2022-07-051-2/+22
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | The RCU dynticks counter is going to be merged into the context tracking subsystem. Prepare with moving the IRQ extended quiescent states entrypoints to context tracking. For now those are dumb redirection to existing RCU calls. [ paulmck: Apply Stephen Rothwell feedback from -next. ] [ paulmck: Apply Nathan Chancellor feedback. ] Acked-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Neeraj Upadhyay <quic_neeraju@quicinc.com> Cc: Uladzislau Rezki <uladzislau.rezki@sony.com> Cc: Joel Fernandes <joel@joelfernandes.org> Cc: Boqun Feng <boqun.feng@gmail.com> Cc: Nicolas Saenz Julienne <nsaenz@kernel.org> Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: Xiongfeng Wang <wangxiongfeng2@huawei.com> Cc: Yu Liao <liaoyu15@huawei.com> Cc: Phil Auld <pauld@redhat.com> Cc: Paul Gortmaker<paul.gortmaker@windriver.com> Cc: Alex Belits <abelits@marvell.com> Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Reviewed-by: Nicolas Saenz Julienne <nsaenzju@redhat.com> Tested-by: Nicolas Saenz Julienne <nsaenzju@redhat.com>
* context_tracking: Take idle eqs entrypoints over RCUFrederic Weisbecker2022-07-051-0/+15
| | | | | | | | | | | | | | | | | | | | | | | | | | | The RCU dynticks counter is going to be merged into the context tracking subsystem. Start with moving the idle extended quiescent states entrypoints to context tracking. For now those are dumb redirections to existing RCU calls. [ paulmck: Apply kernel test robot feedback. ] Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Neeraj Upadhyay <quic_neeraju@quicinc.com> Cc: Uladzislau Rezki <uladzislau.rezki@sony.com> Cc: Joel Fernandes <joel@joelfernandes.org> Cc: Boqun Feng <boqun.feng@gmail.com> Cc: Nicolas Saenz Julienne <nsaenz@kernel.org> Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: Xiongfeng Wang <wangxiongfeng2@huawei.com> Cc: Yu Liao <liaoyu15@huawei.com> Cc: Phil Auld <pauld@redhat.com> Cc: Paul Gortmaker<paul.gortmaker@windriver.com> Cc: Alex Belits <abelits@marvell.com> Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Reviewed-by: Nicolas Saenz Julienne <nsaenzju@redhat.com> Tested-by: Nicolas Saenz Julienne <nsaenzju@redhat.com>
* context_tracking: Split user tracking KconfigFrederic Weisbecker2022-06-301-1/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | Context tracking is going to be used not only to track user transitions but also idle/IRQs/NMIs. The user tracking part will then become a separate feature. Prepare Kconfig for that. [ frederic: Apply Max Filippov feedback. ] Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Neeraj Upadhyay <quic_neeraju@quicinc.com> Cc: Uladzislau Rezki <uladzislau.rezki@sony.com> Cc: Joel Fernandes <joel@joelfernandes.org> Cc: Boqun Feng <boqun.feng@gmail.com> Cc: Nicolas Saenz Julienne <nsaenz@kernel.org> Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: Xiongfeng Wang <wangxiongfeng2@huawei.com> Cc: Yu Liao <liaoyu15@huawei.com> Cc: Phil Auld <pauld@redhat.com> Cc: Paul Gortmaker<paul.gortmaker@windriver.com> Cc: Alex Belits <abelits@marvell.com> Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Reviewed-by: Nicolas Saenz Julienne <nsaenzju@redhat.com> Tested-by: Nicolas Saenz Julienne <nsaenzju@redhat.com>
* context_tracking: Rename context_tracking_cpu_set() to ct_cpu_track_user()Frederic Weisbecker2022-06-301-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | context_tracking_cpu_set() is called in order to tell a CPU to track user/kernel transitions. Since context tracking is going to expand in to also track transitions from/to idle/IRQ/NMIs, the scope of this function name becomes too broad and needs to be made more specific. Also shorten the prefix to align with the new namespace. Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Neeraj Upadhyay <quic_neeraju@quicinc.com> Cc: Uladzislau Rezki <uladzislau.rezki@sony.com> Cc: Joel Fernandes <joel@joelfernandes.org> Cc: Boqun Feng <boqun.feng@gmail.com> Cc: Nicolas Saenz Julienne <nsaenz@kernel.org> Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: Xiongfeng Wang <wangxiongfeng2@huawei.com> Cc: Yu Liao <liaoyu15@huawei.com> Cc: Phil Auld <pauld@redhat.com> Cc: Paul Gortmaker<paul.gortmaker@windriver.com> Cc: Alex Belits <abelits@marvell.com> Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Reviewed-by: Nicolas Saenz Julienne <nsaenzju@redhat.com> Tested-by: Nicolas Saenz Julienne <nsaenzju@redhat.com>
* context_tracking: Rename context_tracking_enter/exit() to ct_user_enter/exit()Frederic Weisbecker2022-06-301-6/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | context_tracking_enter() and context_tracking_exit() have confusing names that don't explain the fact they are referring to user/guest state. Use more self-explanatory names and shrink to the new context tracking prefix instead. Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Neeraj Upadhyay <quic_neeraju@quicinc.com> Cc: Uladzislau Rezki <uladzislau.rezki@sony.com> Cc: Joel Fernandes <joel@joelfernandes.org> Cc: Boqun Feng <boqun.feng@gmail.com> Cc: Nicolas Saenz Julienne <nsaenz@kernel.org> Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: Xiongfeng Wang <wangxiongfeng2@huawei.com> Cc: Yu Liao <liaoyu15@huawei.com> Cc: Phil Auld <pauld@redhat.com> Cc: Paul Gortmaker<paul.gortmaker@windriver.com> Cc: Alex Belits <abelits@marvell.com> Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Reviewed-by: Nicolas Saenz Julienne <nsaenzju@redhat.com> Tested-by: Nicolas Saenz Julienne <nsaenzju@redhat.com>
* context_tracking: Rename context_tracking_user_enter/exit() to ↵Frederic Weisbecker2022-06-301-11/+17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | user_enter/exit_callable() context_tracking_user_enter() and context_tracking_user_exit() are ASM callable versions of user_enter() and user_exit() for architectures that didn't manage to check the context tracking static key from ASM. Change those function names to better reflect their purpose. [ frederic: Apply Max Filippov feedback. ] Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Neeraj Upadhyay <quic_neeraju@quicinc.com> Cc: Uladzislau Rezki <uladzislau.rezki@sony.com> Cc: Joel Fernandes <joel@joelfernandes.org> Cc: Boqun Feng <boqun.feng@gmail.com> Cc: Nicolas Saenz Julienne <nsaenz@kernel.org> Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: Xiongfeng Wang <wangxiongfeng2@huawei.com> Cc: Yu Liao <liaoyu15@huawei.com> Cc: Phil Auld <pauld@redhat.com> Cc: Paul Gortmaker<paul.gortmaker@windriver.com> Cc: Alex Belits <abelits@marvell.com> Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Reviewed-by: Nicolas Saenz Julienne <nsaenzju@redhat.com> Tested-by: Nicolas Saenz Julienne <nsaenzju@redhat.com>
* context_tracking: Rename __context_tracking_enter/exit() to ↵Frederic Weisbecker2022-06-221-10/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | __ct_user_enter/exit() The context tracking namespace is going to expand and some new functions will require even longer names. Start shrinking the context_tracking prefix to "ct" as is already the case for some existing macros, this will make the introduction of new functions easier. Acked-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Neeraj Upadhyay <quic_neeraju@quicinc.com> Cc: Uladzislau Rezki <uladzislau.rezki@sony.com> Cc: Joel Fernandes <joel@joelfernandes.org> Cc: Boqun Feng <boqun.feng@gmail.com> Cc: Nicolas Saenz Julienne <nsaenz@kernel.org> Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: Xiongfeng Wang <wangxiongfeng2@huawei.com> Cc: Yu Liao <liaoyu15@huawei.com> Cc: Phil Auld <pauld@redhat.com> Cc: Paul Gortmaker<paul.gortmaker@windriver.com> Cc: Alex Belits <abelits@marvell.com> Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Reviewed-by: Nicolas Saenz Julienne <nsaenzju@redhat.com> Tested-by: Nicolas Saenz Julienne <nsaenzju@redhat.com>
* context_tracking: Add a note about noinstr VS unsafe context tracking functionsFrederic Weisbecker2022-06-201-0/+34
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Some context tracking functions enter or exit into/from RCU idle mode while using trace-able and lockdep-aware IRQs (un-)masking. As a result those functions can't get tagged as noinstr. This is unlikely to be fixed since these are obsolete APIs. Drop a note about this matter. [ paulmck: Apply Peter Zijlstra feedback. ] Reported-by: Peter Zijlstra <peterz@infradead.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Neeraj Upadhyay <quic_neeraju@quicinc.com> Cc: Uladzislau Rezki <uladzislau.rezki@sony.com> Cc: Joel Fernandes <joel@joelfernandes.org> Cc: Boqun Feng <boqun.feng@gmail.com> Cc: Nicolas Saenz Julienne <nsaenz@kernel.org> Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: Xiongfeng Wang <wangxiongfeng2@huawei.com> Cc: Yu Liao <liaoyu15@huawei.com> Cc: Phil Auld <pauld@redhat.com> Cc: Paul Gortmaker<paul.gortmaker@windriver.com> Cc: Alex Belits <abelits@marvell.com> Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Reviewed-by: Nicolas Saenz Julienne <nsaenzju@redhat.com> Tested-by: Nicolas Saenz Julienne <nsaenzju@redhat.com>
* context_tracking: Ensure that the critical path cannot be instrumentedThomas Gleixner2020-06-111-6/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | context tracking lacks a few protection mechanisms against instrumentation: - While the core functions are marked NOKPROBE they lack protection against function tracing which is required as the function entry/exit points can be utilized by BPF. - static functions invoked from the protected functions need to be marked as well as they can be instrumented otherwise. - using plain inline allows the compiler to emit traceable and probable functions. Fix this by marking the functions noinstr and converting the plain inlines to __always_inline. The NOKPROBE_SYMBOL() annotations are removed as the .noinstr.text section is already excluded from being probed. Cures the following objtool warnings: vmlinux.o: warning: objtool: enter_from_user_mode()+0x34: call to __context_tracking_exit() leaves .noinstr.text section vmlinux.o: warning: objtool: prepare_exit_to_usermode()+0x29: call to __context_tracking_enter() leaves .noinstr.text section vmlinux.o: warning: objtool: syscall_return_slowpath()+0x29: call to __context_tracking_enter() leaves .noinstr.text section vmlinux.o: warning: objtool: do_syscall_64()+0x7f: call to __context_tracking_enter() leaves .noinstr.text section vmlinux.o: warning: objtool: do_int80_syscall_32()+0x3d: call to __context_tracking_enter() leaves .noinstr.text section vmlinux.o: warning: objtool: do_fast_syscall_32()+0x9c: call to __context_tracking_enter() leaves .noinstr.text section and generates new ones... Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org> Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com> Acked-by: Peter Zijlstra <peterz@infradead.org> Link: https://lkml.kernel.org/r/20200505134340.811520478@linutronix.de
* context-tracking: Introduce CONFIG_HAVE_TIF_NOHZFrederic Weisbecker2020-02-141-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | A few archs (x86, arm, arm64) don't rely anymore on TIF_NOHZ to call into context tracking on user entry/exit but instead use static keys (or not) to optimize those calls. Ideally every arch should migrate to that behaviour in the long run. Settle a config option to let those archs remove their TIF_NOHZ definitions. Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Andy Lutomirski <luto@kernel.org> Cc: Russell King <linux@armlinux.org.uk> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will@kernel.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul Burton <paulburton@kernel.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: David S. Miller <davem@davemloft.net>
* context_tracking: Rename context_tracking_is_enabled() => ↵Frederic Weisbecker2019-10-291-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | context_tracking_enabled() Remove the superfluous "is" in the middle of the name. We want to standardize the naming so that it can be expanded through suffixes: context_tracking_enabled() context_tracking_enabled_cpu() context_tracking_enabled_this_cpu() Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Jacek Anaszewski <jacek.anaszewski@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Pavel Machek <pavel@ucw.cz> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rafael J . Wysocki <rjw@rjwysocki.net> Cc: Rik van Riel <riel@surriel.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Viresh Kumar <viresh.kumar@linaro.org> Cc: Wanpeng Li <wanpengli@tencent.com> Cc: Yauheni Kaliuta <yauheni.kaliuta@redhat.com> Link: https://lkml.kernel.org/r/20191016025700.31277-6-frederic@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* treewide: Add SPDX license identifier for missed filesThomas Gleixner2019-05-211-0/+1
| | | | | | | | | | | | | | | | | Add SPDX license identifiers to all files which: - Have no license information of any form - Have EXPORT_.*_SYMBOL_GPL inside which was used in the initial scan/conversion to ignore the file These files fall under the project license, GPL v2 only. The resulting SPDX license identifier is: GPL-2.0-only Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* context_tracking: Switch to new static_branch APIAndy Lutomirski2015-11-241-2/+2
| | | | | | | | | | | | | | | | | This is much less error-prone than the old code. Signed-off-by: Andy Lutomirski <luto@kernel.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/812df7e64f120c5c7c08481f36a8caa9f53b2199.1447361906.git.luto@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* context_tracking: avoid irq_save/irq_restore on guest entry and exitPaolo Bonzini2015-11-101-26/+38
| | | | | | | | | | | | | | | | | | | | | guest_enter and guest_exit must be called with interrupts disabled, since they take the vtime_seqlock with write_seq{lock,unlock}. Therefore, it is not necessary to check for exceptions, nor to save/restore the IRQ state, when context tracking functions are called by guest_enter and guest_exit. Split the body of context_tracking_entry and context_tracking_exit out to __-prefixed functions, and use them from KVM. Rik van Riel has measured this to speed up a tight vmentry/vmexit loop by about 2%. Cc: Andy Lutomirski <luto@kernel.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Paul McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Rik van Riel <riel@redhat.com> Tested-by: Rik van Riel <riel@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* context_tracking: remove duplicate enabled checkPaolo Bonzini2015-11-101-14/+2
| | | | | | | | | | | | | | | | | All calls to context_tracking_enter and context_tracking_exit are already checking context_tracking_is_enabled, except the context_tracking_user_enter and context_tracking_user_exit functions left in for the benefit of assembly calls. Pull the check up to those functions, by making them simple wrappers around the user_enter and user_exit inline functions. Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Paul McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Rik van Riel <riel@redhat.com> Tested-by: Rik van Riel <riel@redhat.com> Acked-by: Andy Lutomirski <luto@kernel.org> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* context_tracking: Inherit TIF_NOHZ through forks instead of context switchesFrederic Weisbecker2015-05-071-25/+19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | TIF_NOHZ is used by context_tracking to force syscall slow-path on every task in order to track userspace roundtrips. As such, it must be set on all running tasks. It's currently explicitly inherited through context switches. There is no need to do it in this fast-path though. The flag could simply be set once for all on all tasks, whether they are running or not. Lets do this by setting the flag for the init task on early boot, and let it propagate through fork inheritance. While at it, mark context_tracking_cpu_set() as init code, we only need it at early boot time. Suggested-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Chris Metcalf <cmetcalf@ezchip.com> Cc: Dave Jones <davej@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Mike Galbraith <umgwanakikbuti@gmail.com> Cc: Paul E . McKenney <paulmck@linux.vnet.ibm.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rafael J . Wysocki <rafael.j.wysocki@intel.com> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1430928266-24888-3-git-send-email-fweisbec@gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* context_tracking: Protect against recursionFrederic Weisbecker2015-05-071-0/+29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Context tracking recursion can happen when an exception triggers in the middle of a call to a context tracking probe. This special case can be caused by vmalloc faults. If an access to a memory area allocated by vmalloc happens in the middle of context_tracking_enter(), we may run into an endless fault loop because the exception in turn calls context_tracking_enter() which faults on the same vmalloc'ed memory, triggering an exception again, etc... Some rare crashes have been reported so lets protect against this with a recursion counter. Reported-by: Dave Jones <davej@redhat.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Reviewed-by: Rik van Riel <riel@redhat.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Chris Metcalf <cmetcalf@ezchip.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Mike Galbraith <umgwanakikbuti@gmail.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Rafael J . Wysocki <rafael.j.wysocki@intel.com> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1430928266-24888-2-git-send-email-fweisbec@gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* context_tracking: Export context_tracking_user_enter/exitRik van Riel2015-03-091-0/+2
| | | | | | | | | | | | | | | Export context_tracking_user_enter/exit so it can be used by KVM. Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: Rik van Riel <riel@redhat.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Will deacon <will.deacon@arm.com> Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Luiz Capitulino <lcapitulino@redhat.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
* context_tracking: Run vtime_user_enter/exit only when state == CONTEXT_USERRik van Riel2015-03-091-4/+8
| | | | | | | | | | | | | | | | | | | | | | Only run vtime_user_enter, vtime_user_exit, and the user enter & exit trace points when we are entering or exiting user state, respectively. The KVM code in guest_enter and guest_exit already take care of calling vtime_guest_enter and vtime_guest_exit, respectively. The RCU code only distinguishes between "idle" and "not idle or kernel". There should be no need to add an additional (unused) state there. Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: Rik van Riel <riel@redhat.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Will deacon <will.deacon@arm.com> Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Luiz Capitulino <lcapitulino@redhat.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
* context_tracking: Generalize context tracking APIs to support user and guestRik van Riel2015-03-091-15/+28
| | | | | | | | | | | | | | | | | | | | | | | | | | Generalize the context tracking APIs to support various nature of contexts. This is performed by splitting out the mechanism from context_tracking_user_enter and context_tracking_user_exit into context_tracking_enter and context_tracking_exit. The nature of the context we track is now detailed in a ctx_state parameter pushed to these APIs, allowing the same functions to not just track kernel <> user space switching, but also kernel <> guest transitions. But leave the old functions in order to avoid breaking ARM, which calls these functions from assembler code, and cannot easily use C enum parameters. Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: Rik van Riel <riel@redhat.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Will deacon <will.deacon@arm.com> Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Luiz Capitulino <lcapitulino@redhat.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
* context_tracking: Rename context symbols to prepare for transition stateFrederic Weisbecker2015-03-091-4/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | Current context tracking symbols are designed to express living state. As such they are prefixed with "IN_": IN_USER, IN_KERNEL. Now we are going to use these symbols to also express state transitions such as context_tracking_enter(IN_USER) or context_tracking_exit(IN_USER). But while the "IN_" prefix works well to express entering a context, it's confusing to depict a context exit: context_tracking_exit(IN_USER) could mean two things: 1) We are exiting the current context to enter user context. 2) We are exiting the user context We want 2) but the reviewer may be confused and understand 1) So lets disambiguate these symbols and rename them to CONTEXT_USER and CONTEXT_KERNEL. Acked-by: Rik van Riel <riel@redhat.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Will deacon <will.deacon@arm.com> Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Luiz Capitulino <lcapitulino@redhat.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
* sched: stop the unbound recursion in preempt_schedule_context()Oleg Nesterov2014-10-281-40/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | preempt_schedule_context() does preempt_enable_notrace() at the end and this can call the same function again; exception_exit() is heavy and it is quite possible that need-resched is true again. 1. Change this code to dec preempt_count() and check need_resched() by hand. 2. As Linus suggested, we can use the PREEMPT_ACTIVE bit and avoid the enable/disable dance around __schedule(). But in this case we need to move into sched/core.c. 3. Cosmetic, but x86 forgets to declare this function. This doesn't really matter because it is only called by asm helpers, still it make sense to add the declaration into asm/preempt.h to match preempt_schedule(). Reported-by: Sasha Levin <sasha.levin@oracle.com> Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Alexander Graf <agraf@suse.de> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Christoph Lameter <cl@linux.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Peter Anvin <hpa@zytor.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Chuck Ebbert <cebbert.lkml@gmail.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Link: http://lkml.kernel.org/r/20141005202322.GB27962@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* x86/kprobes: Fix build errors and blacklist context_track_userMasami Hiramatsu2014-06-141-0/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | This essentially reverts commit: ecd50f714c42 ("kprobes, x86: Call exception_enter after kprobes handled") since it causes build errors with CONFIG_CONTEXT_TRACKING and that has been made from misunderstandings; context_track_user_*() don't involve much in interrupt context, it just returns if in_interrupt() is true. Instead of changing the do_debug/int3(), this just adds context_track_user_*() to kprobes blacklist, since those are still can be called right before kprobes handles int3 and debug exceptions, and probing those will cause an infinite loop. Reported-by: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Borislav Petkov <bp@suse.de> Cc: Kees Cook <keescook@chromium.org> Cc: Jiri Kosina <jkosina@suse.cz> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Seiji Aguchi <seiji.aguchi@hds.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Kees Cook <keescook@chromium.org> Link: http://lkml.kernel.org/r/20140614064711.7865.45957.stgit@kbuild-fedora.novalocal Signed-off-by: Ingo Molnar <mingo@kernel.org>
* asmlinkage: Add explicit __visible to drivers/*, lib/*, kernel/*Andi Kleen2014-05-061-1/+1
| | | | | | | | | | | As requested by Linus add explicit __visible to the asmlinkage users. This marks functions visible to assembler. Tree sweep for rest of tree. Signed-off-by: Andi Kleen <ak@linux.intel.com> Link: http://lkml.kernel.org/r/1398984278-29319-4-git-send-email-andi@firstfloor.org Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
* context_tracking: Wrap static key check into more intuitive function nameFrederic Weisbecker2013-12-021-4/+4
| | | | | | | | | | | | Use a function with a meaningful name to check the global context tracking state. static_key_false() is a bit confusing for reviewers. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Steven Rostedt <rostedt@goodmis.org>
* Merge tag 'v3.12-rc4' into sched/coreIngo Molnar2013-10-091-0/+12
|\ | | | | | | | | | | | | | | | | | | Merge Linux v3.12-rc4 to fix a conflict and also to refresh the tree before applying more scheduler patches. Conflicts: arch/avr32/include/asm/Kbuild Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * arm: Fix build error with context tracking callsFrederic Weisbecker2013-09-271-0/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | ad65782fba50 (context_tracking: Optimize main APIs off case with static key) converted context tracking main APIs to inline function and left ARM asm callers behind. This can be easily fixed by making ARM calling the post static keys context tracking function. We just need to replicate the static key checks there. We'll remove these later when ARM will support the context tracking static keys. Reported-by: Guenter Roeck <linux@roeck-us.net> Reported-by: Russell King <linux@arm.linux.org.uk> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Tested-by: Kevin Hilman <khilman@linaro.org> Cc: Nicolas Pitre <nicolas.pitre@linaro.org> Cc: Anil Kumar <anilk4.v@gmail.com> Cc: Tony Lindgren <tony@atomide.com> Cc: Benoit Cousson <b-cousson@ti.com> Cc: Guenter Roeck <linux@roeck-us.net> Cc: Russell King <linux@arm.linux.org.uk> Cc: Kevin Hilman <khilman@linaro.org>
* | sched: Extract the basic add/sub preempt_count modifiersPeter Zijlstra2013-09-251-1/+1
|/ | | | | | | | | | | | | | | | | | | | | | Rewrite the preempt_count macros in order to extract the 3 basic preempt_count value modifiers: __preempt_count_add() __preempt_count_sub() and the new: __preempt_count_dec_and_test() And since we're at it anyway, replace the unconventional $op_preempt_count names with the more conventional preempt_count_$op. Since these basic operators are equivalent to the previous _notrace() variants, do away with the _notrace() versions. Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/n/tip-ewbpdbupy9xpsjhg960zwbv8@git.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* context_tracking: User/kernel broundary cross trace eventsFrederic Weisbecker2013-08-141-0/+5
| | | | | | | | | | | | | | | | This can be useful to track all kernel/user round trips. And it's also helpful to debug the context tracking subsystem. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Li Zhong <zhong@linux.vnet.ibm.com> Cc: Mike Galbraith <efault@gmx.de> Cc: Kevin Hilman <khilman@linaro.org>
* context_tracking: Optimize context switch off case with static keysFrederic Weisbecker2013-08-141-3/+3
| | | | | | | | | | | | | | | | No need for syscall slowpath if no CPU is full dynticks, rather nop this in this case. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Li Zhong <zhong@linux.vnet.ibm.com> Cc: Mike Galbraith <efault@gmx.de> Cc: Kevin Hilman <khilman@linaro.org>
* context_tracking: Optimize guest APIs off case with static keyFrederic Weisbecker2013-08-141-21/+2
| | | | | | | | | | | | | | | | | | Optimize guest entry/exit APIs with static keys. This minimize the overhead for those who enable CONFIG_NO_HZ_FULL without always using it. Having no range passed to nohz_full= should result in the probes overhead to be minimized. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Li Zhong <zhong@linux.vnet.ibm.com> Cc: Mike Galbraith <efault@gmx.de> Cc: Kevin Hilman <khilman@linaro.org>
* context_tracking: Optimize main APIs off case with static keyFrederic Weisbecker2013-08-141-6/+6
| | | | | | | | | | | | | | | | | | | | | | | Optimize user and exception entry/exit APIs with static keys. This minimize the overhead for those who enable CONFIG_NO_HZ_FULL without always using it. Having no range passed to nohz_full= should result in the probes to be nopped (at least we hope so...). If this proves not be enough in the long term, we'll need to bring an exception slow path by re-routing the exception handlers. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Li Zhong <zhong@linux.vnet.ibm.com> Cc: Mike Galbraith <efault@gmx.de> Cc: Kevin Hilman <khilman@linaro.org>
* context_tracking: Ground setup for static key useFrederic Weisbecker2013-08-141-6/+17
| | | | | | | | | | | | | | | | | | | Prepare for using a static key in the context tracking subsystem. This will help optimizing the off case on its many users: * user_enter, user_exit, exception_enter, exception_exit, guest_enter, guest_exit, vtime_*() Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Li Zhong <zhong@linux.vnet.ibm.com> Cc: Mike Galbraith <efault@gmx.de> Cc: Kevin Hilman <khilman@linaro.org>
* nohz: Only enable context tracking on full dynticks CPUsFrederic Weisbecker2013-08-131-0/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | The context tracking subsystem has the ability to selectively enable the tracking on any defined subset of CPU. This means that we can define a CPU range that doesn't run the context tracking and another range that does. Now what we want in practice is to enable the tracking on full dynticks CPUs only. In order to perform this, we just need to pass our full dynticks CPU range selection from the full dynticks subsystem to the context tracking. This way we can spare the overhead of RCU user extended quiescent state and vtime maintainance on the CPUs that are outside the full dynticks range. Just keep in mind the raw context tracking itself is still necessary everywhere. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Li Zhong <zhong@linux.vnet.ibm.com> Cc: Mike Galbraith <efault@gmx.de> Cc: Kevin Hilman <khilman@linaro.org>
* context_tracking: Fix runtime CPU off-caseFrederic Weisbecker2013-08-131-19/+33
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | As long as the context tracking is enabled on any CPU, even a single one, all other CPUs need to keep track of their user <-> kernel boundaries cross as well. This is because a task can sleep while servicing an exception that happened in the kernel or in userspace. Then when the task eventually wakes up and return from the exception, the CPU needs to know if we resume in userspace or in the kernel. exception_exit() get this information from exception_enter() that saved the previous state. If the CPU where the exception happened didn't keep track of these informations, exception_exit() doesn't know which state tracking to restore on the CPU where the task got migrated and we may return to userspace with the context tracking subsystem thinking that we are in kernel mode. This can be fixed in the long term if we move our context tracking probes on very low level arch fast path user <-> kernel boundary, although even that is worrisome as an exception can still happen in the few instructions between the probe and the actual iret. Also we are not yet ready to set these probes in the fast path given the potential overhead problem it induces. So let's fix this by always enable context tracking even on CPUs that are not in the full dynticks range. OTOH we can spare the rcu_user_*() and vtime_user_*() calls there because the tick runs on these CPUs and we can handle RCU state machine and cputime accounting through it. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Li Zhong <zhong@linux.vnet.ibm.com> Cc: Mike Galbraith <efault@gmx.de> Cc: Kevin Hilman <khilman@linaro.org>
* context_tracing: Fix guest accounting with native vtimeFrederic Weisbecker2013-08-131-2/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | 1) If context tracking is enabled with native vtime accounting (which combo is useless except for dev testing), we call vtime_guest_enter() and vtime_guest_exit() on host <-> guest switches. But those are stubs in this configurations. As a result, cputime is not correctly flushed on kvm context switches. 2) If context tracking runs but is disabled on some CPUs, those CPUs end up calling __guest_enter/__guest_exit which in turn call vtime_account_system(). We don't want to call this because we run in tick based accounting for these CPUs. Refactor the guest_enter/guest_exit code such that all combinations finally work. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Li Zhong <zhong@linux.vnet.ibm.com> Cc: Mike Galbraith <efault@gmx.de> Cc: Kevin Hilman <khilman@linaro.org>
* sched: Consolidate open coded preemptible() checksFrederic Weisbecker2013-08-131-2/+1
| | | | | | | | | | | | | | | | | | | | preempt_schedule() and preempt_schedule_context() open code their preemptability checks. Use the standard API instead for consolidation. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Li Zhong <zhong@linux.vnet.ibm.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Borislav Petkov <bp@alien8.de> Cc: Alex Shi <alex.shi@intel.com> Cc: Paul Turner <pjt@google.com> Cc: Mike Galbraith <efault@gmx.de> Cc: Vincent Guittot <vincent.guittot@linaro.org>
* Merge branch 'sched-urgent-for-linus' of ↵Linus Torvalds2013-06-201-0/+40
|\ | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull scheduler fixes from Ingo Molnar: "Two smaller fixes - plus a context tracking tracing fix that is a bit bigger" * 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: tracing/context-tracking: Add preempt_schedule_context() for tracing sched: Fix clear NOHZ_BALANCE_KICK sched/x86: Construct all sibling maps if smt
| * tracing/context-tracking: Add preempt_schedule_context() for tracingSteven Rostedt2013-06-191-0/+40
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Dave Jones hit the following bug report: =============================== [ INFO: suspicious RCU usage. ] 3.10.0-rc2+ #1 Not tainted ------------------------------- include/linux/rcupdate.h:771 rcu_read_lock() used illegally while idle! other info that might help us debug this: RCU used illegally from idle CPU! rcu_scheduler_active = 1, debug_locks = 0 RCU used illegally from extended quiescent state! 2 locks held by cc1/63645: #0: (&rq->lock){-.-.-.}, at: [<ffffffff816b39fd>] __schedule+0xed/0x9b0 #1: (rcu_read_lock){.+.+..}, at: [<ffffffff8109d645>] cpuacct_charge+0x5/0x1f0 CPU: 1 PID: 63645 Comm: cc1 Not tainted 3.10.0-rc2+ #1 [loadavg: 40.57 27.55 13.39 25/277 64369] Hardware name: Gigabyte Technology Co., Ltd. GA-MA78GM-S2H/GA-MA78GM-S2H, BIOS F12a 04/23/2010 0000000000000000 ffff88010f78fcf8 ffffffff816ae383 ffff88010f78fd28 ffffffff810b698d ffff88011c092548 000000000023d073 ffff88011c092500 0000000000000001 ffff88010f78fd60 ffffffff8109d7c5 ffffffff8109d645 Call Trace: [<ffffffff816ae383>] dump_stack+0x19/0x1b [<ffffffff810b698d>] lockdep_rcu_suspicious+0xfd/0x130 [<ffffffff8109d7c5>] cpuacct_charge+0x185/0x1f0 [<ffffffff8109d645>] ? cpuacct_charge+0x5/0x1f0 [<ffffffff8108dffc>] update_curr+0xec/0x240 [<ffffffff8108f528>] put_prev_task_fair+0x228/0x480 [<ffffffff816b3a71>] __schedule+0x161/0x9b0 [<ffffffff816b4721>] preempt_schedule+0x51/0x80 [<ffffffff816b4800>] ? __cond_resched_softirq+0x60/0x60 [<ffffffff816b6824>] ? retint_careful+0x12/0x2e [<ffffffff810ff3cc>] ftrace_ops_control_func+0x1dc/0x210 [<ffffffff816be280>] ftrace_call+0x5/0x2f [<ffffffff816b681d>] ? retint_careful+0xb/0x2e [<ffffffff816b4805>] ? schedule_user+0x5/0x70 [<ffffffff816b4805>] ? schedule_user+0x5/0x70 [<ffffffff816b6824>] ? retint_careful+0x12/0x2e ------------[ cut here ]------------ What happened was that the function tracer traced the schedule_user() code that tells RCU that the system is coming back from userspace, and to add the CPU back to the RCU monitoring. Because the function tracer does a preempt_disable/enable_notrace() calls the preempt_enable_notrace() checks the NEED_RESCHED flag. If it is set, then preempt_schedule() is called. But this is called before the user_exit() function can inform the kernel that the CPU is no longer in user mode and needs to be accounted for by RCU. The fix is to create a new preempt_schedule_context() that checks if the kernel is still in user mode and if so to switch it to kernel mode before calling schedule. It also switches back to user mode coming back from schedule in need be. The only user of this currently is the preempt_enable_notrace(), which is only used by the tracing subsystem. Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/1369423420.6828.226.camel@gandalf.local.home Signed-off-by: Ingo Molnar <mingo@kernel.org>